JP6136037B2 - Magnesium alloy cast material, magnesium alloy cast coil material, magnesium alloy wrought material, magnesium alloy joint material, method for producing magnesium alloy cast material, method for producing magnesium alloy wrought material, and method for producing magnesium alloy member - Google Patents

Description

本発明は、マグネシウム合金(以下、Mg合金と呼ぶことがある)からなる各種の部材、特にプレス加工といった塑性加工が施されたMg合金部材の素材に適したMg合金鋳造材、Mg合金鋳造コイル材、Mg合金展伸材、Mg合金接合材、及びMg合金鋳造材の製造方法、並びにMg合金部材に関するものである。特に、難燃性及び加工性に優れるMg合金鋳造材、Mg合金展伸材に関するものである。   The present invention relates to various members made of a magnesium alloy (hereinafter sometimes referred to as an Mg alloy), in particular, an Mg alloy cast material and an Mg alloy cast coil suitable for a material of an Mg alloy member subjected to plastic working such as press working. The present invention relates to a material, a Mg alloy wrought material, a Mg alloy bonding material, a method for producing a Mg alloy cast material, and a Mg alloy member. In particular, the present invention relates to an Mg alloy cast material and an Mg alloy wrought material that are excellent in flame retardancy and workability.

マグネシウム合金は、構造材用金属の中で最軽量の合金であり、資源量、リサイクル性、衝撃吸収性、耐凹み性といった様々な面で優れている。そのため、近年、携帯電話やノート型パーソナルコンピュータといった携帯用電気・電子機器類の筐体や自動車部品、鉄道車両用部品などの各種の部材の構成材料にマグネシウム合金が利用されてきている。   Magnesium alloy is the lightest alloy among structural metals and is excellent in various aspects such as resource amount, recyclability, shock absorption, and dent resistance. Therefore, in recent years, a magnesium alloy has been used as a constituent material of various members such as a casing of a portable electric / electronic device such as a mobile phone or a notebook personal computer, an automobile part, and a railway vehicle part.

マグネシウム合金からなる製品は、ダイカスト法やチクソモールド法による鋳造材が主流である。特許文献1は、連続鋳造法により製造した鋳造板に圧延加工を施すことで、プレス加工性に優れるマグネシウム合金板が得られる旨を開示している。   The products made of magnesium alloys are mainly cast materials by die casting or thixomolding. Patent Document 1 discloses that a magnesium alloy plate excellent in press workability can be obtained by rolling a cast plate manufactured by a continuous casting method.

国際公開第2006/003899号International Publication No. 2006/003899

マグネシウム合金は、非常に活性で燃え易い。マグネシウム合金の難燃性を高めるためには、特許文献1に記載されるようにCaの添加が効果的である。しかし、Caを添加すると加工性が低下する。具体的には、鋳造材に圧延といった展伸加工を施したり、展伸加工が施された展伸材にプレス加工といった塑性加工を施したりすると割れが生じ易く、展伸材や塑性加工材の生産性の低下を招く。   Magnesium alloys are very active and flammable. In order to increase the flame retardancy of the magnesium alloy, as described in Patent Document 1, addition of Ca is effective. However, when Ca is added, the workability decreases. Specifically, if the cast material is subjected to wrench processing such as rolling, or plastic processing such as press processing is applied to the wrought material that has been wrought, cracking is likely to occur. This leads to a decrease in productivity.

従って、圧延材といった展伸材やプレス加工材といった塑性加工材を生産性よく製造するために、その素材となる鋳造材自体が加工性に優れることが望まれる。   Therefore, in order to manufacture a wrought material such as a rolled material and a plastic material such as a press-worked material with high productivity, it is desired that the cast material itself as the material is excellent in workability.

そこで、本発明の目的の一つは、難燃性に優れる上に、加工性にも優れるマグネシウム合金鋳造材を提供することにある。また、本発明の他の目的は、難燃性及び加工性の双方に優れるマグネシウム合金鋳造材を製造可能なマグネシウム合金鋳造材の製造方法を提供することにある。   Accordingly, one of the objects of the present invention is to provide a magnesium alloy cast material that is excellent in flame retardancy and excellent in workability. Another object of the present invention is to provide a method for producing a magnesium alloy cast material capable of producing a magnesium alloy cast material excellent in both flame retardancy and workability.

更に、本発明の他の目的は、難燃性及び加工性の双方に優れるマグネシウム合金展伸材、この展伸材の素材に適したマグネシウム合金鋳造コイル材を提供することにある。   Another object of the present invention is to provide a magnesium alloy wrought material excellent in both flame retardancy and workability, and a magnesium alloy cast coil material suitable for the material of the wrought material.

更に、本発明の他の目的は、難燃性及び機械的特性の双方に優れるマグネシウム合金部材、このマグネシウム合金部材の素材に適したマグネシウム合金接合材を提供することにある。   Another object of the present invention is to provide a magnesium alloy member excellent in both flame retardancy and mechanical properties, and a magnesium alloy bonding material suitable for the material of the magnesium alloy member.

本発明者らは、難燃性を向上するためにCaを比較的多く添加すると共に、強度といった機械的特性や耐食性も向上するためにAlも添加したマグネシウム合金を対象として、種々の条件で鋳造材を作製した。その結果、連続鋳造法を利用すると共に、鋳造時の冷却速度を非常に速くして急冷することでCaを含有するマグネシウム合金であっても、圧延といった展伸加工性に優れる鋳造材が得られること、この鋳造材を素材とすることでプレス加工といった塑性加工性に優れる展伸材が得られるとの知見を得た。また、展伸加工性に優れる鋳造材の組織を調べたところ、特定の鋳造組織を有していた。本発明は、上記知見に基づくものである。   The inventors of the present invention cast a magnesium alloy under various conditions for adding a relatively large amount of Ca in order to improve flame retardancy, and for a magnesium alloy in which Al is also added to improve mechanical properties such as strength and corrosion resistance. A material was prepared. As a result, it is possible to obtain a cast material that is excellent in stretch workability such as rolling, even if it is a magnesium alloy containing Ca by using a continuous casting method and quenching rapidly by cooling at the time of casting. In addition, the present inventors have found that a wrought material having excellent plastic workability such as press working can be obtained by using this cast material as a raw material. Moreover, when the structure of the cast material excellent in stretch workability was examined, it had a specific cast structure. The present invention is based on the above findings.

本発明のマグネシウム合金鋳造材は、Alを含有するマグネシウム合金からなる鋳造材であり、上記マグネシウム合金は、Alを2質量％以上11質量％以下、かつCaを0.1質量％以上10質量％以下含有する。そして、この鋳造材は、DAS(dendrite arm spacing)が4.5μm未満である。   The magnesium alloy cast material of the present invention is a cast material made of a magnesium alloy containing Al. The magnesium alloy contains Al in an amount of 2 to 11% by mass and Ca in an amount of 0.1 to 10% by mass. To do. The cast material has a DAS (dendrite arm spacing) of less than 4.5 μm.

上記本発明鋳造材は、以下の本発明製造方法により製造することができる。本発明のマグネシウム合金鋳造材の製造方法は、Alを含有するマグネシウム合金からなる鋳造材を製造する方法であり、以下の準備工程と鋳造工程とを具える。
準備工程:Alを2質量％以上11質量％以下、かつCaを0.1質量％以上10質量％以下含有するマグネシウム合金の溶湯を準備する工程。
鋳造工程:一対の鋳造ロールを具える双ロール連続鋳造機により上記溶湯を連続鋳造して鋳造材を製造する工程。
そして、上記鋳造時の冷却速度を650℃/秒以上とする。 The said casting material of this invention can be manufactured with the following this invention manufacturing method. The method for producing a magnesium alloy cast material of the present invention is a method for producing a cast material made of a magnesium alloy containing Al, and includes the following preparation process and casting process.
Preparation step: a step of preparing a molten magnesium alloy containing Al in a range of 2 mass% to 11 mass% and Ca in a range of 0.1 mass% to 10 mass%.
Casting step: A step of producing a cast material by continuously casting the molten metal with a twin roll continuous casting machine having a pair of casting rolls.
And the cooling rate at the time of the said casting shall be 650 degrees C / sec or more.

Caの含有量を多くするほど合金の液相線温度及び固相線温度が低下して合金溶湯が凝固し難くなり、完全に凝固するまでの時間が長くなる。即ち、Caを比較的多く含む、特に0.1質量％以上含むMg合金溶湯では、未凝固の状態が長くなり易く、その結果、DASが大きくなるなどして加工性の低下を招く、と考えられる。本発明製造方法は、冷却速度を非常に速めることでDASを非常に小さくすることができ、DASが4.5μm未満の本発明鋳造材を製造することができる。DASが十分に小さいことで本発明鋳造材は、圧延などの展伸加工を施した際に割れが生じ難く、加工性に優れる上に、Caを特定の範囲で含有することで、難燃性にも優れる。   As the Ca content increases, the liquidus temperature and solidus temperature of the alloy decrease, and the molten alloy becomes difficult to solidify, and the time until complete solidification increases. That is, it is considered that the Mg alloy melt containing a relatively large amount of Ca, particularly 0.1% by mass or more, tends to be long in an unsolidified state, and as a result, the DAS becomes large and the workability is lowered. In the production method of the present invention, the DAS can be made very small by greatly increasing the cooling rate, and the cast material of the present invention having a DAS of less than 4.5 μm can be produced. Since the DAS is sufficiently small, the cast material of the present invention is less prone to cracking when subjected to extension processing such as rolling, and is excellent in workability, and also contains Ca in a specific range, thus being flame retardant. Also excellent.

本発明製造方法の一形態として、上記一対の鋳造ロール間のギャップをg_r、上記鋳造ロールに向かって上記溶湯を排出するノズルの開口部の間隔をg_nとするとき、g_n＜g_rとなるように、上記鋳造ロール間のギャップ及び上記ノズルの開口部の間隔の少なくとも一方を調整する形態が挙げられる。 As one form of the manufacturing method of the present invention, when the gap between the pair of casting rolls is g _r and the gap between the nozzle openings for discharging the molten metal toward the casting roll is g _n , g _n <g _r The form which adjusts at least one of the gap between the said casting rolls and the space | interval of the opening part of the said nozzle so that it may become may be mentioned.

本発明者らは、冷却速度を速めるためには、溶湯をできるだけ速やかに鋳造ロールにより冷却することが好ましい、との知見を得た。上記形態は、ノズルの開口部の間隔が鋳造ロール間のギャップよりも小さいことで、ノズルの開口部を鋳造ロールに近づけたり、ノズル本体の厚さを厚くして断熱性を高めたりすることができる。従って、上記形態は、高温状態の溶湯を鋳造ロールに接触できることから、鋳造時の冷却速度を十分に大きくでき、DASが十分に小さい鋳造材を製造することができる。   The present inventors have found that it is preferable to cool the molten metal with a casting roll as quickly as possible in order to increase the cooling rate. In the above embodiment, the gap between the nozzle openings is smaller than the gap between the casting rolls, and the nozzle openings can be brought closer to the casting roll, or the thickness of the nozzle body can be increased to increase the heat insulation. it can. Therefore, since the high temperature state molten metal can contact a casting roll, the said form can fully increase the cooling rate at the time of casting, and can manufacture the casting material whose DAS is small enough.

本発明製造方法の一形態として、上記準備工程では、所定量のうちの一部のCaを含有するCa含有溶湯を作製してから、残部のCaを添加して上記マグネシウム合金の溶湯を作製する形態が挙げられる。   As one form of the manufacturing method of the present invention, in the preparation step, a Ca-containing molten metal containing a predetermined amount of Ca is produced, and then the remaining Ca is added to produce the molten magnesium alloy. A form is mentioned.

本発明者らは、Caを上記特定の範囲で含有する鋳造材を製造する場合、多段階に分けてCaを混合させることが好ましい、との知見を得た。上記形態は、Ca含有溶湯に更にCaを添加することでCaを均一的に混合できるため、Caの偏在を抑制できる。従って、上記形態は、Caが偏在して凝固し難い箇所が存在し、DASが大きな箇所が局所的に形成され、その結果加工性が低下する、といった不具合の発生を効果的に防止できる。   The inventors of the present invention have found that it is preferable to mix Ca in multiple stages when producing a cast material containing Ca in the above specific range. Since the said form can mix Ca uniformly by adding Ca further to Ca containing molten metal, it can suppress uneven distribution of Ca. Therefore, the said form can prevent effectively generation | occurrence | production of the malfunction that the location where Ca is unevenly distributed and there exists a location which is hard to solidify, a location where a DAS is large is formed locally, and as a result workability falls.

本発明鋳造材の一形態として、上記マグネシウム合金がAlとCaとを含む第一の金属間化合物を含有し、上記第一の金属間化合物の最大径が5μm以下である形態が挙げられる。   As one form of the cast material of the present invention, there is a form in which the magnesium alloy contains a first intermetallic compound containing Al and Ca, and the maximum diameter of the first intermetallic compound is 5 μm or less.

Caを多く含有するほど難燃性を高められるものの、上述のように凝固し難くなることで鋳造材に粗大な金属間化合物が形成され易い。ここで、添加元素にAlを含有するMg合金は、高強度で耐食性に優れる。しかし、AlとCaとの双方を上記範囲で含有するMg合金では、AlとCaとを含有する金属間化合物が粗大な粒子となって晶出し易い。粗大な金属間化合物は、鋳造材に圧延などの展伸加工を施す際に割れの起点となり易く、鋳造材の加工性の低下を招く。上記粗大な金属間化合物を圧延などの展伸加工時の負荷により微細にしようとすると、展伸加工装置に過大な負荷が加えられる上に、素材が不均一に加工される。また、上記粗大な金属間化合物が展伸材に残存すると、この展伸材にプレス加工などの塑性加工を施す際、上記粗大な金属間化合物が割れの起点となり、展伸材の加工性の低下を招く。上記形態は、AlとCaとを含む金属間化合物が十分に小さいことで、割れの起点になり難く、展伸加工の加工性に優れる。また、本発明鋳造材に展伸加工を施してなる展伸材(本発明展伸材)には、鋳造材中のAlとCaとを含む金属間化合物が残存するものの、当該金属間化合物は、上述のような非常に微細な粒子であることから、当該展伸材にプレス加工などの塑性加工を施す際にも割れの起点になり難く、この展伸材も加工性に優れる。上記金属間化合物が微細に晶出した上記形態の鋳造材は、上述した連続鋳造時の冷却速度を非常に大きくする本発明製造方法により製造できる。   Although the flame retardance is enhanced as the Ca content increases, a coarse intermetallic compound is likely to be formed in the cast material due to difficulty in solidification as described above. Here, the Mg alloy containing Al as an additive element has high strength and excellent corrosion resistance. However, in an Mg alloy containing both Al and Ca in the above range, an intermetallic compound containing Al and Ca is likely to be crystallized as coarse particles. A coarse intermetallic compound tends to be a starting point of cracking when the cast material is subjected to a stretching process such as rolling, and causes a decrease in the workability of the cast material. If the coarse intermetallic compound is to be made finer by the load during the stretching process such as rolling, an excessive load is applied to the stretching apparatus and the material is processed unevenly. Also, if the coarse intermetallic compound remains in the wrought material, the coarse intermetallic compound becomes a starting point of cracking when the wrought material is subjected to plastic working such as press working, and the workability of the wrought material is reduced. Incurs a decline. In the above-mentioned form, since the intermetallic compound containing Al and Ca is sufficiently small, it is difficult to become a starting point of cracking and is excellent in workability of the drawing process. Moreover, although the intermetallic compound containing Al and Ca in the cast material remains in the expanded material obtained by subjecting the cast material of the present invention to the extension processing (present invention expanded material), the intermetallic compound is Since the particles are very fine as described above, they are unlikely to become a starting point of cracking when the wrought material is subjected to plastic working such as press working, and this wrought material is also excellent in workability. The cast material having the above-described form in which the intermetallic compound is finely crystallized can be produced by the production method of the present invention in which the cooling rate during the continuous casting described above is extremely increased.

本発明鋳造材の一形態として、上記マグネシウム合金がAlとCaとを含む第一の金属間化合物を含有し、上記DASと上記第一の金属間化合物の最大径との差の絶対値が2.5μm以下である形態が挙げられる。   As one form of the cast material of the present invention, the magnesium alloy contains a first intermetallic compound containing Al and Ca, the absolute value of the difference between the maximum diameter of the DAS and the first intermetallic compound is 2.5. The form which is below μm can be mentioned.

本発明鋳造材は、DASが小さいことから、上記差が小さい上記形態は、AlとCaとを含む金属間化合物も小さく、かつ、この金属間化合物はDASと同程度な大きさであるといえる。また、上記形態は、上記差が小さいことから、微細な鋳造組織中に、同様に微細な金属間化合物が存在した均一的な組織といえる。このような微細で均一的な組織であることから、上記形態は、上記金属間化合物が割れの起点となり難く、加工性により優れる。   Since the cast material of the present invention has a small DAS, it can be said that the above-mentioned form with the small difference is also a small intermetallic compound containing Al and Ca, and this intermetallic compound is about the same size as the DAS. . Moreover, since the said difference is small, it can be said that the said form is a uniform structure | tissue in which the fine intermetallic compound existed similarly in the fine cast structure. Since it is such a fine and uniform structure, the above-described form is less likely to cause cracking of the intermetallic compound and is more excellent in workability.

本発明鋳造材の一形態として、上記マグネシウム合金がAlとCaとを含む第一の金属間化合物を含有し、上記DASと上記AlとCaとを含む第一の金属間化合物の最大径との和が5μm以下である形態が挙げられる。   As one form of the cast material of the present invention, the magnesium alloy contains a first intermetallic compound containing Al and Ca, and the maximum diameter of the first intermetallic compound containing DAS and the Al and Ca. The form whose sum is 5 micrometers or less is mentioned.

本発明鋳造材は、DASが小さいことから、上記和が小さい上記形態は、AlとCaとを含む金属間化合物も十分に小さいといえる。従って、上記形態は、微細な鋳造組織中に非常に微細な金属間化合物が存在した均一的な組織といえる。このような微細で均一的な組織であることから、上記形態は、上記金属間化合物が割れの起点となり難く、加工性により優れる。上記和が小さい上に、上述した差も小さい形態であると、加工性に更に優れる。   Since the cast material of the present invention has a small DAS, it can be said that the above-mentioned form having a small sum also has a sufficiently small intermetallic compound containing Al and Ca. Therefore, the above form can be said to be a uniform structure in which a very fine intermetallic compound is present in a fine cast structure. Since it is such a fine and uniform structure, the above-described form is less likely to cause cracking of the intermetallic compound and is more excellent in workability. When the sum is small and the above-described difference is small, the workability is further improved.

本発明鋳造材の一形態として、上記マグネシウム合金がAlとCaとを含む第一の金属間化合物と、AlとMgとを含む第二の金属間化合物とを含有しており、上記第一の金属間化合物と上記第二の金属間化合物との両金属間化合物が隣り合って存在する箇所を具える形態が挙げられる。また、上記形態の鋳造材を素材として、圧延などの展伸加工を施すことで、本発明展伸材が得られる。本発明のマグネシウム合金展伸材は、Alを2質量％以上11質量％以下、かつCaを0.1質量％以上10質量％以下含有するマグネシウム合金からなる展伸材であり、上記マグネシウム合金は、更に、AlとCaとを含む第一の金属間化合物と、AlとMgとを含む第二の金属間化合物とを含有する。そして、この展伸材では、上記第一の金属間化合物と上記第二の金属間化合物との両金属間化合物の粒子が隣り合った粒子群を含む。   As one form of the cast material of the present invention, the magnesium alloy contains a first intermetallic compound containing Al and Ca, and a second intermetallic compound containing Al and Mg. The form which provides the location where both the intermetallic compounds of an intermetallic compound and said 2nd intermetallic compound exist adjacently is mentioned. Moreover, this invention extended material is obtained by performing the extending | stretching process, such as rolling, using the cast material of the said form as a raw material. The magnesium alloy wrought material of the present invention is a wrought material composed of a magnesium alloy containing Al in an amount of 2% by mass to 11% by mass and Ca in an amount of 0.1% by mass to 10% by mass. And a first intermetallic compound containing Al and Ca, and a second intermetallic compound containing Al and Mg. The wrought material includes a particle group in which particles of both intermetallic compounds of the first intermetallic compound and the second intermetallic compound are adjacent to each other.

本発明者らが調べたところ、Ca及びAlを上記特定の範囲で含有するMg合金を上記特定の冷却速度で連続鋳造して得られた鋳造材は、上記両金属間化合物が隣り合った状態でデンドライト組織のアーム間に晶出し、両金属間化合物が網目状に存在する組織を有する、との知見を得た。また、この組織を有する鋳造材に圧延といった展伸加工を施すと、得られた展伸材(本発明展伸材)も、上記両金属間化合物の粒子が隣り合ってなる微細な粒子群が分散して存在する組織を有する、との知見を得た。更に、上記微細な粒子群が分散した組織を有する展伸材は、プレス加工といった塑性加工を施した際、割れなどが生じ難く、加工性に優れる、との知見を得た。従って、上記形態の鋳造材は、圧延などの展伸加工の加工性に優れる上に、プレス加工といった塑性加工の加工性に優れる展伸材が得られる。上記本発明展伸材は、プレス加工といった塑性加工の加工性に優れる上に、Caを特定の範囲で含有することで難燃性にも優れる。   When the present inventors investigated, the casting material obtained by continuously casting Mg alloy containing Ca and Al in the above specific range at the above specific cooling rate is a state where the above-mentioned intermetallic compounds are adjacent to each other. Thus, crystallization occurred between the arms of the dendrite structure, and it was found that the intermetallic compound has a structure in a network form. In addition, when the cast material having this structure is subjected to a stretching process such as rolling, the obtained stretched material (the present stretched material) is also a fine particle group in which the particles of the two intermetallic compounds are adjacent to each other. The knowledge that it has the structure | tissue which exists in a dispersion | distribution was acquired. Furthermore, it has been found that the wrought material having a structure in which the fine particle groups are dispersed is not easily cracked and has excellent workability when subjected to plastic working such as press working. Therefore, the cast material having the above-described form is excellent in the workability of the extending process such as rolling, and the expanded material is excellent in the workability of plastic working such as press working. The above-mentioned wrought material of the present invention is excellent in workability of plastic working such as press working, and also has excellent flame retardancy by containing Ca in a specific range.

本発明鋳造材の一形態として、上記マグネシウム合金がAlとCaとを含む第一の金属間化合物を含有し、この金属間化合物の平均粒径が2μm以下である形態が挙げられる。   As one form of the cast material of the present invention, there may be mentioned a form in which the magnesium alloy contains a first intermetallic compound containing Al and Ca, and the average particle size of the intermetallic compound is 2 μm or less.

上記形態は、AlとCaとを含む金属間化合物の平均粒径が小さいことで、上記Mg合金中に存在する金属間化合物はいずれも微細といえる。従って、上記形態は、上記金属間化合物が割れの起点となり難く、加工性により優れる。特に、上記形態において、上記金属間化合物の最大径が5μm以下であると、更に割れ難く、加工性に更に優れる。この鋳造材に圧延加工などの展伸加工を施すことで得られた展伸材(本発明展伸材の一形態)もAlとCaとを含む金属間化合物の最大径が5μm以下で、かつ平均粒径が2μm以下となる。この展伸材も、上記金属間化合物がいずれも微細であって割れの起点になり難く、プレス加工などの塑性加工の加工性に優れる。また、この展伸材は、微細で均一的な大きさの金属間化合物が分散した組織を有することで分散強化による強度の向上も期待できる。この展伸材を素材としてプレス加工といった塑性加工を施した塑性加工材も、上記分散強化された組織を維持することで、強度、耐衝撃性、剛性に優れる。   The said form is that the average particle diameter of the intermetallic compound containing Al and Ca is small, and it can be said that all the intermetallic compounds which exist in the said Mg alloy are fine. Therefore, the said form does not become the starting point of a crack of the said intermetallic compound, and is excellent by workability. In particular, in the above embodiment, when the maximum diameter of the intermetallic compound is 5 μm or less, it is further difficult to break and the workability is further improved. The wrought material (one form of the wrought material of the present invention) obtained by performing a wrought process such as rolling on the cast material also has a maximum diameter of an intermetallic compound containing Al and Ca of 5 μm or less, and The average particle size is 2 μm or less. This wrought material is also excellent in workability of plastic working such as press working because the intermetallic compounds are all fine and hardly start a crack. In addition, since the wrought material has a structure in which fine and uniform intermetallic compounds are dispersed, the strength can be improved by dispersion strengthening. A plastic working material subjected to plastic working such as press working using the stretched material as a raw material also has excellent strength, impact resistance, and rigidity by maintaining the above-described dispersion strengthened structure.

本発明鋳造材又は本発明展伸材の一形態として、マグネシウム合金鋳造材又はマグネシウム合金展伸材において、当該鋳造材又は当該展伸材の厚さ方向の表層領域及び中央領域に存在するAlとCaとを含む第一の金属間化合物が微細で、均一的な大きさである形態が挙げられる。上記表層領域とは、上記鋳造材又は上記展伸材の表面から厚さ方向に当該鋳造材又は当該展伸材の厚さの20％までの領域とする。上記中央領域とは、上記鋳造材又は上記展伸材の厚さ方向の中心から表面側に向かって当該鋳造材又は当該展伸材の厚さの10％までの領域とする。そして、上記鋳造材又は上記展伸材はいずれも、上記表層領域及び上記中央領域の各領域における上記AlとCaとを含む第一の金属間化合物の最大径が5μm以下、かつ平均粒径が2μm以下であり、更に、上記表層領域における上記平均粒径と、上記中央領域における上記平均粒径との差が20％以内である。   As one form of the cast material of the present invention or the stretched material of the present invention, in the magnesium alloy cast material or the magnesium alloy stretched material, Al present in the surface region and the central region in the thickness direction of the cast material or the stretched material; Examples include a form in which the first intermetallic compound containing Ca is fine and has a uniform size. The surface layer region is a region up to 20% of the thickness of the cast material or the wrought material in the thickness direction from the surface of the cast material or the wrought material. The central region is a region up to 10% of the thickness of the cast material or the stretched material from the center in the thickness direction of the cast material or the stretched material toward the surface side. And as for the said cast material or the said wrought material, the maximum diameter of the 1st intermetallic compound containing the said Al and Ca in each area | region of the said surface layer area | region and the said center area | region is 5 micrometers or less, and an average particle diameter is Further, the difference between the average particle size in the surface layer region and the average particle size in the central region is within 20%.

上記形態は、表面領域と中央領域とに存在する上記金属間化合物の大きさの差が小さいことから、鋳造材の全体又は展伸材の全体に亘って、上記金属間化合物の大きさが均一的で微細である、といえる。従って、上記形態は、圧延などの展伸加工やプレス加工などの塑性加工時に割れなどが生じ難く、加工性に優れる。   In the above embodiment, since the difference in the size of the intermetallic compound existing in the surface region and the central region is small, the size of the intermetallic compound is uniform over the entire cast material or the entire stretched material. It can be said that the target is fine. Therefore, the said form does not produce a crack etc. easily at the time of plastic processing, such as extension processing, such as rolling, and press processing, and is excellent in workability.

本発明鋳造材又は本発明展伸材の一形態として、上記マグネシウム合金がAlとMgとを含む第二の金属間化合物及びAlとMnとを含む第三の金属間化合物の少なくとも一方を含有し、上記第二の金属間化合物及び上記第三の金属間化合物の少なくとも一方の金属間化合物の平均粒径が2μm以下である形態が挙げられる。   As one form of the cast material of the present invention or the expanded material of the present invention, the magnesium alloy contains at least one of a second intermetallic compound containing Al and Mg and a third intermetallic compound containing Al and Mn. An example in which the average particle size of at least one of the second intermetallic compound and the third intermetallic compound is 2 μm or less is included.

本発明鋳造材や本発明展伸材は、上述のAlとCaとを含有する金属間化合物だけでなく、上記形態のようにAlとMgとを含有する金属間化合物やAlとMnとを含有する金属間化合物を含有する形態が有り得る。本発明鋳造材では、上述のように連続鋳造時の冷却速度を大きくして急冷することで、上述の金属間化合物のいずれもが小さく均一的であり、これら金属間化合物が割れの起点となり難い。従って、上記形態の鋳造材は、圧延などの展伸加工性に優れる。また、この鋳造材を素材として得られた本発明展伸材も、素材(上記形態の鋳造材)と同様に上述の金属間化合物がいずれも小さく均一的である。従って、上記形態の展伸材は、プレス加工などの塑性加工性に優れる。   The cast material of the present invention and the expanded material of the present invention contain not only the above-described intermetallic compound containing Al and Ca, but also an intermetallic compound containing Al and Mg as in the above form, and Al and Mn. There may be a form containing an intermetallic compound. In the cast material of the present invention, the above-mentioned intermetallic compounds are all small and uniform by increasing the cooling rate at the time of continuous casting and quenching as described above, and these intermetallic compounds are unlikely to become the starting point of cracking. . Therefore, the cast material of the above form is excellent in the stretch workability such as rolling. Further, the wrought material of the present invention obtained using this cast material as a raw material also has the above-mentioned intermetallic compounds small and uniform in the same manner as the raw material (the cast material of the above form). Therefore, the wrought material of the above form is excellent in plastic workability such as press working.

本発明鋳造材又は本発明展伸材の一形態として、上記マグネシウム合金が、更に、Zn,Mn,Si,Sr,Y,Cu,Ag,Ce,Sn,Li,Zr,Be,Ni,Au及び希土類元素(Y,Ceを除く)から選択される少なくとも1種の元素を、Alとの合計で7.3質量％以上含有し、残部がMg及び不純物からなる形態が挙げられる。   As one form of the cast material of the present invention or the expanded material of the present invention, the magnesium alloy further includes Zn, Mn, Si, Sr, Y, Cu, Ag, Ce, Sn, Li, Zr, Be, Ni, Au and Examples include a form in which at least one element selected from rare earth elements (excluding Y and Ce) is contained in a total of 7.3% by mass or more with Al, and the balance is Mg and impurities.

上記形態は、種々の元素を含有することで、強度、耐塑性変形性、耐食性、耐熱性などの種々の特性に優れる。   The said form is excellent in various characteristics, such as intensity | strength, plastic deformation resistance, corrosion resistance, and heat resistance, by containing various elements.

上記本発明鋳造材は種々の形状を取り得る。例えば、上記本発明鋳造材からなる長さが100m以上の板状材を巻き取ってなる本発明マグネシウム合金鋳造コイル材が挙げられる。   The cast material of the present invention can take various shapes. For example, the magnesium alloy cast coil material of the present invention obtained by winding a plate-like material having a length of 100 m or more made of the cast material of the present invention.

本発明鋳造材は、上述のように連続鋳造で製造されるため、100m以上といった長尺な板状材を容易に製造でき、この板状材を巻き取ることで本発明コイル材が得られる。本発明コイル材は、圧延などの展伸加工の素材に利用する場合、展伸加工装置に素材を連続的に供給可能であるため、展伸材の生産性の向上に寄与することができる。得られた展伸材を巻き取ることで展伸コイル材を製造できる。そして、この展伸コイル材は、プレス加工などの塑性加工の素材に利用する場合、塑性加工装置に素材を連続的に供給可能であるため、塑性加工材(本発明マグネシウム合金部材の一形態)の生産性の向上に寄与することができる。   Since the cast material of the present invention is manufactured by continuous casting as described above, a long plate material of 100 m or more can be easily manufactured, and the coil material of the present invention can be obtained by winding up the plate material. When the coil material of the present invention is used as a material for an extension process such as rolling, the material can be continuously supplied to an extension processing apparatus, which can contribute to an improvement in the productivity of the extension material. A rolled coil material can be manufactured by winding up the obtained stretched material. And, when this stretched coil material is used as a material for plastic working such as press working, since the material can be continuously supplied to the plastic working device, the plastic working material (one form of the magnesium alloy member of the present invention) It can contribute to the improvement of productivity.

本発明展伸材の一形態として、上記AlとCaとを含む第一の金属間化合物の最大径と上記AlとMgとを含む第二の金属間化合物の最大径との差の絶対値が2μm下である形態が挙げられる。   As one aspect of the present invention, the absolute value of the difference between the maximum diameter of the first intermetallic compound containing Al and Ca and the maximum diameter of the second intermetallic compound containing Al and Mg is The form which is 2 micrometers below is mentioned.

上記形態は、上記第一の金属間化合物と上記第二の金属間化合物との両金属間化合物の差が小さいことから、これら両金属間化合物の大きさのばらつきが小さく、均一的な組織といえる。従って、上記形態は、上記両金属間化合物が割れの起点となり難く、加工性により優れる。   Since the difference between the two intermetallic compounds between the first intermetallic compound and the second intermetallic compound is small, the variation in the size of these two intermetallic compounds is small, and the uniform structure I can say that. Therefore, the said form is more excellent in workability than the said intermetallic compound being a starting point of a crack.

本発明展伸材の一形態として、上記マグネシウム合金展伸材の発火温度が600℃以上、引張強さが300MPa以上である形態が挙げられる。   As one form of the wrought material of the present invention, there is a form in which the ignition temperature of the magnesium alloy wrought material is 600 ° C. or higher and the tensile strength is 300 MPa or higher.

上記形態は、上述のように加工性に優れる上に、発火温度が十分に高いことで耐熱性に優れ、引張強さが十分に高いことで高強度である。そのため、上記形態は、耐熱性及び高強度が望まれる種々の分野の部材であって、プレス加工といった塑性加工が施されてなる部材の素材に好適に利用することができる。   In addition to being excellent in workability as described above, the above form is excellent in heat resistance because the ignition temperature is sufficiently high, and high in strength because the tensile strength is sufficiently high. Therefore, the said form is a member of the various field | areas where heat resistance and high intensity | strength are desired, Comprising: It can utilize suitably for the raw material of the member in which plastic processing, such as press work, is given.

上記本発明展伸材を素材とした本発明マグネシウム合金部材を提案する。本発明のマグネシウム合金部材は、上記本発明展伸材に室温以上500℃以下の加熱温度でプレス加工を施してなる。   The magnesium alloy member of the present invention made of the above-described expanded material of the present invention is proposed. The magnesium alloy member of the present invention is obtained by subjecting the above-mentioned expanded material of the present invention to press working at a heating temperature of room temperature to 500 ° C.

上述のように本発明展伸材は、加工性に優れることから、プレス加工を良好に行えて、生産性よく本発明マグネシウム合金部材を製造することができる。複雑な形状や加工度が高いプレス加工を行う場合には、加熱温度を高めるほど塑性加工性を高められ、高精度に成形することができる。また、本発明展伸材は、上述のように発火温度が高く、高強度であることから、本発明展伸材を素材とする本発明マグネシウム合金部材も発火温度が高く、高強度である。   As described above, the wrought material of the present invention is excellent in workability, so that the press working can be performed well and the magnesium alloy member of the present invention can be manufactured with high productivity. In the case of performing press working with a complicated shape and a high degree of processing, the plastic workability can be improved as the heating temperature is increased, and the molding can be performed with high accuracy. In addition, since the wrought material of the present invention has a high ignition temperature and high strength as described above, the magnesium alloy member of the present invention made from the wrought material of the present invention also has a high ignition temperature and high strength.

上記本発明展伸材を複数用意して接合し、大型材とした本発明マグネシウム合金接合材を提案する。本発明のマグネシウム合金接合材は、複数の上記本発明展伸材と、上記本発明展伸材同士が摩擦撹拌接合により接合された接合領域とを具える。   A magnesium alloy bonding material of the present invention is proposed in which a plurality of the above-mentioned expanded materials of the present invention are prepared and bonded to form a large material. The magnesium alloy bonding material of the present invention includes a plurality of the above-described expanded materials of the present invention and a bonding region in which the expanded materials of the present invention are bonded together by friction stir welding.

本発明者らが調べたところ、板状の本発明展伸材を摩擦撹拌接合により接合して一体化された接合材は、プレス加工といった塑性加工を施した場合でも、接合領域で破断せず、接合領域を有していない一様な素材と同様に扱える、との知見を得た。複数の本発明展伸材を摩擦撹拌接合により接合することで、任意の大きさや任意の平面形状にすることができ、本発明接合材は、大型な塑性加工材の素材や所望の形状の塑性加工材の素材に好適に利用することができる。   As a result of investigations by the present inventors, a joint material obtained by joining plate-like expanded materials of the present invention by friction stir welding does not break in the joining region even when subjected to plastic working such as press working. They obtained knowledge that they can be treated in the same way as a uniform material that does not have a bonding region. By joining a plurality of the wrought materials of the present invention by friction stir welding, they can be made into an arbitrary size or an arbitrary planar shape. The inventive bonding material is a material of a large plastic work material or a plastic material of a desired shape. It can utilize suitably for the raw material of a processed material.

本発明マグネシウム合金鋳造材、鋳造コイル材、展伸材、及び接合材は、難燃性及び加工性の双方に優れる。本発明マグネシウム合金部材は、難燃性に優れる上に、高強度である。本発明マグネシウム合金鋳造材の製造方法は、本発明鋳造材を製造することができる。   The magnesium alloy cast material, cast coil material, wrought material, and bonding material of the present invention are excellent in both flame retardancy and workability. The magnesium alloy member of the present invention is excellent in flame retardancy and high strength. The manufacturing method of this invention magnesium alloy casting material can manufacture this invention casting material.

図1(A)は、試料No.1-22の鋳造材の顕微鏡写真(5000倍)、図1(B)は、試料No.1-22の展伸材の顕微鏡写真(5000倍)である。Fig. 1 (A) is a micrograph (5000 times) of the cast material of sample No. 1-22, and Fig. 1 (B) is a micrograph (5000 times) of the stretched material of sample No. 1-22. . 図2は、試料No.1-22の鋳造材のFE-EPMAによる組成マッピング像であり、図2(A)はCaの濃度分布、図2(B)はAlの濃度分布を示す。2 is a composition mapping image by FE-EPMA of the cast material of sample No. 1-22, FIG. 2 (A) shows the Ca concentration distribution, and FIG. 2 (B) shows the Al concentration distribution. 図3(A)は、試料No.100の鋳造材の顕微鏡写真(5000倍)、図3(B)は、試料No.100の展伸材の顕微鏡写真(5000倍)である。3A is a micrograph (5000 times) of the cast material of sample No. 100, and FIG. 3B is a micrograph (5000 times) of the stretched material of sample No. 100. 図4は、鋳造ロールのギャップとノズルの開口部の間隔との関係を説明する説明図である。FIG. 4 is an explanatory view illustrating the relationship between the gap of the casting roll and the interval between the openings of the nozzle.

以下、本発明をより詳細に説明する。
[組成]
本発明マグネシウム合金鋳造材、鋳造コイル材、展伸材(接合材を構成する素材である場合を含む)、マグネシウム合金部材を構成するマグネシウム合金はいずれも、Ca及びAlを必須の添加元素とし、残部がMg(50質量％以上)及び不純物からなる。 Hereinafter, the present invention will be described in more detail.
[composition]
Magnesium alloy cast material, cast coil material, wrought material (including the case of a material constituting the bonding material), magnesium alloy constituting the magnesium alloy member, both Ca and Al as essential additive elements, The balance consists of Mg (50% by mass or more) and impurities.

Caを0.1質量％以上含有することで難燃性に優れ、発火温度を向上できる。Caの含有量が多いほど発火温度を高められ、難燃性を考慮すると、0.5質量％以上、更に1質量％以上が好ましい。但し、Caが多過ぎると加工性の低下を招くため、上限を10質量％とする。加工性を考慮すると、Caの含有量は3質量％以下がより好ましい。   By containing at least 0.1% by mass of Ca, it has excellent flame retardancy and can improve the ignition temperature. The higher the Ca content, the higher the ignition temperature. In view of flame retardancy, 0.5% by mass or more, preferably 1% by mass or more is preferable. However, if Ca is too much, workability is lowered, so the upper limit is made 10 mass%. In consideration of workability, the Ca content is more preferably 3% by mass or less.

Alを2質量％以上含有するマグネシウム合金は、強度及び耐食性に優れる。Alの含有量は、多いほど強度及び耐食性に優れるマグネシウム合金となることから、強度及び耐食性を考慮すると、2.5質量％以上、更に4.5質量％以上が好ましい。但し、Alが多過ぎると加工性の低下を招くことから、Alの含有量の上限を11質量％とする。Alの含有量が7.3質量％以上、特に8.3質量％〜9.5質量％であるMg-Al系合金は、強度や硬度といった機械的特性、耐食性、塑性加工性に優れて好ましい。   A magnesium alloy containing 2% by mass or more of Al is excellent in strength and corrosion resistance. The higher the Al content, the more excellent the strength and corrosion resistance of the magnesium alloy. Therefore, considering the strength and corrosion resistance, it is preferably 2.5% by mass or more, and more preferably 4.5% by mass or more. However, if there is too much Al, workability will be reduced, so the upper limit of the Al content is 11% by mass. An Mg-Al alloy having an Al content of 7.3% by mass or more, particularly 8.3% by mass to 9.5% by mass is preferable because of excellent mechanical properties such as strength and hardness, corrosion resistance, and plastic workability.

Ca及びAl以外の添加元素は、Zn,Mn,Si,Sr,Y,Cu,Ag,Ce,Sn,Li,Zr,Be,Ni,Au及び希土類元素(Y,Ceを除く)から選択される1種以上の元素が挙げられる。これらの元素を含む場合、各元素の含有量は、0.01質量％以上10質量％以下、好ましくは0.1質量％以上5質量％以下が挙げられる。上記Ca及びAl以外の添加元素と、Alとの合計の含有量が7.3質量％以上であることが好ましい。Alに加えて上記添加元素を含有することで、元素の種類にもよるが、強度や硬度、靭性、耐衝撃性、耐凹み性といった機械的特性、制振性、耐食性、耐熱性などの種々の特性を向上することができる。上記添加元素のうち、Si,Sn,Y,Ce及び希土類元素(Y,Ceを除く)から選択される1種以上の元素を合計0.001質量％以上、好ましくは合計0.1質量％以上5質量％以下含有すると、耐熱性、難燃性をより向上することができる。希土類元素を含有する場合、その合計含有量は0.1質量％以上が好ましく、特に、Yを含有する場合、その含有量は0.5質量％以上が好ましい。不純物は、例えば、Feなどが挙げられる。   Additive elements other than Ca and Al are selected from Zn, Mn, Si, Sr, Y, Cu, Ag, Ce, Sn, Li, Zr, Be, Ni, Au, and rare earth elements (excluding Y and Ce) One or more elements are listed. When these elements are contained, the content of each element is 0.01 mass% or more and 10 mass% or less, preferably 0.1 mass% or more and 5 mass% or less. The total content of additive elements other than Ca and Al and Al is preferably 7.3% by mass or more. By including the above additive elements in addition to Al, depending on the type of element, various mechanical properties such as strength, hardness, toughness, impact resistance, and dent resistance, vibration damping, corrosion resistance, heat resistance, etc. The characteristics can be improved. Among the above additive elements, one or more elements selected from Si, Sn, Y, Ce and rare earth elements (excluding Y and Ce) are in total 0.001% by mass or more, preferably in total 0.1% by mass or more and 5% by mass or less When it contains, heat resistance and a flame retardance can be improved more. When the rare earth element is contained, the total content is preferably 0.1% by mass or more, and particularly when Y is contained, the content is preferably 0.5% by mass or more. Examples of the impurity include Fe.

Mg-Al系合金のより具体的な組成は、例えば、ASTM規格におけるAZ系合金(Mg-Al-Zn系合金、Zn:0.2質量％〜1.5質量％)、AM系合金(Mg-Al-Mn系合金、Mn:0.15質量％〜0.5質量％)、Mg-Al-RE系合金(RE:希土類元素)、AJ系合金(Mg-Al-Sr系合金、Sr:0.2質量％〜7.0質量％)などが挙げられる。特に、Alを8.3質量％〜9.5質量％、Znを0.5質量％〜1.5質量％含有するMg-Al系合金、代表的にはAZ91合金をベース合金とすると、耐食性、機械的特性に優れて好ましい。   More specific compositions of Mg-Al alloys include, for example, AZ alloys (Mg-Al-Zn alloys, Zn: 0.2% to 1.5% by mass), AM alloys (Mg-Al-Mn) according to ASTM standards. Alloy, Mn: 0.15 mass% to 0.5 mass%), Mg-Al-RE alloy (RE: rare earth element), AJ alloy (Mg-Al-Sr alloy, Sr: 0.2 mass% to 7.0 mass%) Etc. In particular, a Mg-Al alloy containing 8.3 mass% to 9.5 mass% Al and 0.5 mass% to 1.5 mass% Zn, typically AZ91 alloy, is preferable because of its excellent corrosion resistance and mechanical properties. .

[DAS]
本発明鋳造材は、DASが4.5μm未満と非常に小さい。鋳造時の冷却速度を大きくする(速める)ことでDASを更に小さくすることができ、DASが4μm以下、更に3μm以下の鋳造材とすることができる。DASが小さいほど、加工性に優れる傾向にあり、特に下限を設けない。DASの測定方法は後述する。 [DAS]
The cast material of the present invention has a very small DAS of less than 4.5 μm. By increasing (accelerating) the cooling rate at the time of casting, the DAS can be further reduced, and a cast material having a DAS of 4 μm or less and further 3 μm or less can be obtained. The smaller the DAS, the better the workability, and there is no particular lower limit. The method for measuring DAS will be described later.

[Al-Ca金属間化合物]
(鋳造材、鋳造コイル材)
本発明鋳造材(鋳造コイル材を構成する板状材を含む)の代表的な組織では、AlとCaとを含む金属間化合物(例えば、Al₂Caなど)が存在し、当該金属間化合物が微細である。AlとCaとを含む金属間化合物は、主として晶出物であり、鋳造時に生成された大きさが、鋳造以降の工程においても実質的に維持される、或いは加工によって更に微細になる。本発明製造方法では、鋳造時の冷却速度を特定の大きさにして急冷することで、AlとCaとを含む金属間化合物の最大径を5μm以下にできる。鋳造時の冷却速度を大きくすることで、上記最大径を更に小さくすることができ、当該最大径が3μm以下、更に1.5μm以下の鋳造材とすることができる。Caの含有量などによっては、上記最大径が1μm以下という上記金属間化合物が非常に微細な形態とすることができる。上記金属間化合物は、微細であるほど割れの起点になり難く、上記最大径の下限は特に設けない。上記金属間化合物、及び後述する金属間化合物の最大径、平均粒径などの測定方法は後述する。 [Al-Ca intermetallic compound]
(Casting material, Casting coil material)
In a typical structure of the cast material of the present invention (including a plate material constituting a cast coil material), an intermetallic compound containing Al and Ca (for example, Al ₂ Ca) exists, and the intermetallic compound is present. It is fine. The intermetallic compound containing Al and Ca is mainly a crystallized product, and the size generated at the time of casting is substantially maintained in the processes after casting or becomes finer by processing. In the production method of the present invention, the maximum diameter of the intermetallic compound containing Al and Ca can be reduced to 5 μm or less by rapidly cooling the casting at a specific cooling rate. By increasing the cooling rate during casting, the maximum diameter can be further reduced, and the maximum diameter can be 3 μm or less, further 1.5 μm or less. Depending on the Ca content and the like, the intermetallic compound having the maximum diameter of 1 μm or less can be in a very fine form. The finer the intermetallic compound, the harder it becomes to be the starting point of cracking, and there is no particular lower limit on the maximum diameter. The measuring method of the said intermetallic compound and the maximum diameter of an intermetallic compound mentioned later, an average particle diameter, etc. is mentioned later.

本発明鋳造材の代表的な組織では、AlとCaとを含む金属間化合物がいずれも微細で均一的な大きさである。具体的には、上記金属間化合物の平均粒径が2μm以下である。この形態は、DASが小さく微細な鋳造組織中に、微細で均一的な金属間化合物が存在するという微細で均一的な組織を有することから、粗大な金属間化合物の粒子が局所的に存在して、この粗大な粒子が割れの起点になる、といった不具合が生じ難く、加工性に優れる。鋳造条件や組成などによっては、上記金属間化合物の平均粒径が1.5μm以下、更に1.0μm以下の鋳造材とすることができる。   In the typical structure of the cast material of the present invention, the intermetallic compounds containing Al and Ca are all fine and uniform in size. Specifically, the average particle size of the intermetallic compound is 2 μm or less. Since this form has a fine and uniform structure in which a fine and uniform intermetallic compound exists in a fine cast structure with a small DAS, coarse intermetallic particles are locally present. Thus, the problem that the coarse particles are the starting point of cracking hardly occurs and the processability is excellent. Depending on casting conditions, composition, etc., a cast material having an average particle size of the intermetallic compound of 1.5 μm or less, and further 1.0 μm or less can be obtained.

本発明鋳造材の代表的な組織では、当該鋳造材の厚さ方向の全体に亘って、AlとCaとを含む金属間化合物のばらつきが小さく、或いは実質的にばらつきがなく、均一的な大きさである。具体的には、上述した表層領域及び中央領域の両領域において上記金属間化合物の最大径及び平均粒径が小さく、かつ両領域の平均粒径の差が小さい(20％以内)。鋳造条件や組成などによっては、上記両領域の平均粒径の差が15％以下の鋳造材とすることができる。   In the typical structure of the cast material of the present invention, the variation in the intermetallic compound containing Al and Ca is small or substantially uniform throughout the entire thickness direction of the cast material, and has a uniform size. That's it. Specifically, the maximum diameter and average particle size of the intermetallic compound are small in both the surface layer region and the central region described above, and the difference in average particle size between the two regions is small (within 20%). Depending on the casting conditions, composition, etc., it is possible to obtain a cast material in which the difference in average particle size between the two regions is 15% or less.

(展伸材)
本発明鋳造材中に存在するAlとCaとを含む金属間化合物は、上述のように微細であることで、当該鋳造材に圧延といった展伸加工を施す際、過度に負荷を与えることなく圧延を行える。そのため、得られた展伸材中に存在する上記金属間化合物の大きさは、鋳造材のときの大きさが実質的に維持される、或いは、展伸加工により更に小さい。従って、本発明展伸材の代表的な組織では、AlとCaとを含む金属間化合物(例えば、Al₂Caなど)が存在し、当該金属間化合物が微細である。例えば、上記金属間化合物の最大径が5μm以下、更に3.0μm以下、特に1.5μm以下を満たす形態や、平均粒径が2μm以下、更に1μm以下、特に0.5μm以下を満たす形態が挙げられる。また、上述した表層領域及び中央領域の両領域において上記金属間化合物の最大径及び平均粒径が小さく、かつ両領域の平均粒径の差が20％以下、更に15％以下の展伸材とすることができる。 (Spread)
The intermetallic compound containing Al and Ca present in the cast material of the present invention is fine as described above, and is rolled without applying an excessive load when the cast material is subjected to extension processing such as rolling. Can be done. Therefore, the size of the intermetallic compound present in the obtained wrought material is substantially maintained as the size of the cast material, or is further reduced by the wrench processing. Therefore, in a typical structure of the wrought material of the present invention, an intermetallic compound containing Al and Ca (for example, Al ₂ Ca) is present, and the intermetallic compound is fine. For example, a form in which the maximum diameter of the intermetallic compound satisfies 5 μm or less, further 3.0 μm or less, especially 1.5 μm or less, or an average particle diameter of 2 μm or less, further 1 μm or less, particularly 0.5 μm or less can be mentioned. Further, in both the surface layer region and the central region described above, the maximum diameter and the average particle size of the intermetallic compound are small, and the difference between the average particle sizes of the two regions is 20% or less, and further, 15% or less can do.

(接合材)
上記本発明展伸材を複数用意して接合した本発明接合材において接合領域を除く箇所は、上記本発明展伸材の組織(例えば、AlとCaとを含む金属間化合物の最大径:5μm以下、平均粒径:2μm以下、表層領域と中央領域とにおける平均粒径の差:20％以内)を実質的に維持する。 (Bonding material)
In the present invention bonding material prepared by joining a plurality of the present invention stretched material, the portion excluding the bonding region is the structure of the present invention stretched material (for example, the maximum diameter of the intermetallic compound containing Al and Ca: 5 μm Hereinafter, the average particle size: 2 μm or less and the difference in average particle size between the surface layer region and the central region: within 20% are substantially maintained.

(マグネシウム合金部材)
上記本発明展伸材や本発明接合材にプレス加工などの塑性加工を施した本発明マグネシウム合金部材において、塑性加工が実質的に施されなかった箇所(代表的には平坦な箇所)や加工度が小さい塑性加工が施された場合は、上記本発明展伸材の組織(例えば、AlとCaとを含む金属間化合物の最大径:5μm以下、平均粒径:2μm以下、表層領域と中央領域とにおける平均粒径の差:20％以内)を実質的に維持する。 (Magnesium alloy member)
In the magnesium alloy member of the present invention in which the present invention expanded material or the present invention bonding material is subjected to plastic working such as press working, a place where the plastic working is not substantially performed (typically a flat place) or processing When plastic working is performed at a low degree, the structure of the wrought material of the present invention (for example, the maximum diameter of intermetallic compounds including Al and Ca: 5 μm or less, average particle diameter: 2 μm or less, surface layer region and center The difference in the average particle diameter from the region: within 20%) is substantially maintained.

[DASとAl-Ca金属間化合物との関係]
上述のようにDASが小さく、かつAlとCaとを含む金属間化合物も小さいことで、本発明鋳造材(鋳造コイル材を構成する板状材を含む)の代表的な組織では、DASと上記金属間化合物との差も小さい(絶対値で2.5μm以下)。即ち、この組織は、DASが小さく微細な鋳造組織中に、微細で均一的な大きさで、かつDASと同様な大きさの上記金属間化合物が分散して存在する組織といえる。このような特有の微細・分散組織を有することで、上記金属間化合物が割れの起点になり難く、加工性により優れる。鋳造条件や組成などによっては、上記差の絶対値が2μm以下といった鋳造材とすることができる。 [Relationship between DAS and Al-Ca intermetallic compound]
As described above, the DAS is small, and the intermetallic compound containing Al and Ca is also small, so in the typical structure of the cast material of the present invention (including the plate-like material constituting the cast coil material), the DAS and the above The difference from the intermetallic compound is also small (absolute value is 2.5 μm or less). That is, this structure can be said to be a structure in which the above-mentioned intermetallic compound having a fine and uniform size and the same size as DAS is dispersed in a fine cast structure with a small DAS. By having such a specific fine and dispersed structure, the intermetallic compound is less likely to be a starting point of cracking, and is excellent in workability. Depending on casting conditions, composition, etc., a casting material having an absolute value of the difference of 2 μm or less can be obtained.

上述のようにDASが小さく、かつAlとCaとを含む金属間化合物も小さいことで、本発明鋳造材(鋳造コイル材を構成する板状材を含む)の代表的な組織では、DASと上記金属間化合物との和も小さい(5μm以下)。上記和が小さいことで、DAS及び上記金属間化合物の双方が十分に小さく、加工性に優れる。鋳造条件や組成などによっては、上記和が5μm以下、更に4μm以下、特に3.5μm以下といった鋳造材としたり、更に、上述の差の絶対値が2.5μm以下、かつ上記和が5μm以下の双方を満たす鋳造材としたりすることができる。   As described above, the DAS is small, and the intermetallic compound containing Al and Ca is also small, so in the typical structure of the cast material of the present invention (including the plate-like material constituting the cast coil material), the DAS and the above The sum with the intermetallic compound is also small (5 μm or less). Since the sum is small, both DAS and the intermetallic compound are sufficiently small, and processability is excellent. Depending on the casting conditions and composition, the sum is 5 μm or less, further 4 μm or less, particularly 3.5 μm or less, or the absolute value of the above difference is 2.5 μm or less, and the sum is 5 μm or less. It can be a cast material that fills.

[Al-Mg金属間化合物]
(鋳造材、鋳造コイル材)
本発明鋳造材(鋳造コイル材を構成する板状材を含む)は、Alを含有することから、当該鋳造材の代表的な組織では、AlとMgとを含む金属間化合物(例えば、Al₁₂Mg₁₇)が、主として、AlとCaとを含む金属間化合物に隣接して存在する。本発明者らが調べたところ、AlとCaとを含む金属間化合物は、AlとMgとを含む金属間化合物よりも優先的に結晶相を形成する傾向にある、との知見を得た。従って、本発明では、DASと共に、加工性の阻害要因となり易いAlとCaとを含む金属間化合物の大きさを特定の範囲にすることを提案する。 [Al-Mg intermetallic compound]
(Casting material, Casting coil material)
Since the cast material of the present invention (including the plate material constituting the cast coil material) contains Al, in a typical structure of the cast material, an intermetallic compound containing Al and Mg (for example, Al ₁₂ Mg ₁₇ ) exists mainly adjacent to an intermetallic compound containing Al and Ca. As a result of investigations by the present inventors, it was found that an intermetallic compound containing Al and Ca tends to form a crystalline phase preferentially over an intermetallic compound containing Al and Mg. Therefore, in the present invention, it is proposed that the size of an intermetallic compound containing Al and Ca, which easily becomes a hindrance to workability, is set within a specific range together with DAS.

上述のように鋳造時の冷却速度を特定の大きさにして急冷することで、AlとMgとを含む金属間化合物も微細にすることができ、例えば、平均粒径を2μm以下とすることができる。この場合、AlとMgとを含む金属間化合物及び上述したAlとCaとを含む金属間化合物のいずれもが微細であるため、これら二種の金属間化合物が隣接して存在していても、各金属間化合物が割れの起点になり難く、加工性を阻害し難い。   As mentioned above, the cooling rate during casting is set to a specific size and rapidly cooled, so that an intermetallic compound containing Al and Mg can also be made fine, for example, the average particle size can be 2 μm or less. it can. In this case, since both the intermetallic compound containing Al and Mg and the above-described intermetallic compound containing Al and Ca are fine, even if these two types of intermetallic compounds exist adjacently, Each intermetallic compound is unlikely to become a starting point of cracking, and workability is hardly hindered.

(展伸材)
上記二種の金属間化合物が隣接した状態で含有する本発明鋳造材に展伸加工を施してなる本発明展伸材も、上記二種類の金属間化合物からなる粒子が隣接して存在する、という特有の組織を有する。展伸材が、上記二種類の金属間化合物が隣接して存在する組織を有することは、鋳造材においても上記二種類の金属間化合物が隣接して存在していたことを示す指標の一つとなる。 (Spread)
The present expanded material obtained by subjecting the present cast material, which contains the two types of intermetallic compounds to be adjacent to each other, also has particles adjacent to the two types of intermetallic compounds, It has a unique organization. The fact that the wrought material has a structure in which the two types of intermetallic compounds are present adjacent to each other is one of the indicators indicating that the two types of intermetallic compounds were also present in the cast material. Become.

AlとMgとを含む金属間化合物は、晶出物もあるものの、主として析出物である。析出物は、鋳造以降の製造工程の熱履歴により成長することがあるものの、鋳造材中に存在するときに微細であると、展伸材中においても微細な状態で存在し易い。例えば、AlとMgとを含む金属間化合物の平均粒径が2μm以下である展伸材とすることができる。また、展伸加工時の負荷により、AlとMgとを含む金属間化合物をより微細にすることもでき、当該金属間化合物の平均粒径が1μm以下、更に0.5μm以下といった展伸材とすることができる。   Intermetallic compounds containing Al and Mg are mainly precipitates, although there are crystallized substances. Although the precipitate may grow due to the thermal history of the manufacturing process after casting, if it is fine when present in the cast material, it is likely to be present in a fine state in the wrought material. For example, a wrought material having an average particle diameter of an intermetallic compound containing Al and Mg of 2 μm or less can be obtained. In addition, the intermetallic compound containing Al and Mg can be made finer due to the load during the stretching process, and the average particle size of the intermetallic compound is 1 μm or less, and further, the expanded material is 0.5 μm or less. be able to.

AlとMgとを含む金属間化合物が微細である場合、上述のようにAlとCaとを含む金属間化合物が微細であることから、これら二種類の金属間化合物が均一的な大きさである展伸材とすることができる。例えば、上記二種類の金属間化合物の最大径の差(絶対値)が2μm以下、製造条件などによっては、更に1.5μm以下である展伸材とすることができ、割れの起点になり難い。   When the intermetallic compound containing Al and Mg is fine, since the intermetallic compound containing Al and Ca is fine as described above, these two types of intermetallic compounds have a uniform size. Can be wrought material. For example, a wrought material in which the difference (absolute value) of the maximum diameters of the two types of intermetallic compounds is 2 μm or less and, depending on manufacturing conditions, can be further 1.5 μm or less, and is unlikely to become a starting point of cracking.

[Al-Mn金属間化合物]
本発明鋳造材(鋳造コイル材を構成する板状材を含む)は、組成によっては、更に別の金属間化合物を含有する形態、即ち、3種以上の複数種の金属間化合物を含有する形態になり得る。例えば、添加元素に更にMnを含有する場合、AlとMnとを含む金属間化合物(例えば、MnAl₄など)を含有する形態が挙げられる。上述のように鋳造時の冷却速度を特定の大きさにして急冷することから、上記AlとMnとを含む金属間化合物も微細であり、例えば、平均粒径が2μm以下を満たす。従って、この金属間化合物自体も割れの起点になり難い。 [Al-Mn intermetallic compound]
The cast material of the present invention (including the plate material constituting the cast coil material), depending on the composition, further contains another intermetallic compound, that is, a form containing three or more types of intermetallic compounds. Can be. For example, when the additive element further contains Mn, a form containing an intermetallic compound containing Al and Mn (for example, MnAl ₄ etc.) can be mentioned. As described above, the cooling rate at the time of casting is set to a specific size for rapid cooling, so the intermetallic compound containing Al and Mn is also fine, and for example, the average particle size satisfies 2 μm or less. Therefore, this intermetallic compound itself is also unlikely to become a starting point of cracking.

AlとMnとを含む金属間化合物が存在する鋳造材を素材として得られた本発明展伸材も、当該金属間化合物が存在する形態となり得る。AlとMnとを含む金属間化合物も主として晶出物であることから、鋳造以降の製造工程の熱履歴により成長することがあるものの、上述のように鋳造材のときに微細であると、展伸材中においても微細にし易い。例えば、AlとMnとを含む金属間化合物の平均粒径が2μm以下である展伸材とすることができる。また、上述のように展伸加工時の負荷により、AlとMnとを含む金属間化合物をより微細にすることもでき、当該金属間化合物の平均粒径が0.5μm以下、更に0.3μm以下といった展伸材とすることができる。   The wrought material of the present invention obtained using a cast material containing an intermetallic compound containing Al and Mn as a raw material can also be in a form in which the intermetallic compound is present. Since intermetallic compounds containing Al and Mn are also mainly crystallized products, they may grow due to the thermal history of the manufacturing process after casting. It is easy to make it fine even during drawing. For example, a wrought material in which the average particle size of the intermetallic compound containing Al and Mn is 2 μm or less can be obtained. In addition, as described above, the intermetallic compound containing Al and Mn can be made finer due to the load during the stretching process, and the average particle size of the intermetallic compound is 0.5 μm or less, further 0.3 μm or less. Can be wrought material.

AlとMgとを含む金属間化合物やAlとMnとを含む金属間化合物が存在する展伸材を用いた本発明接合材において接合領域以外の箇所や、本発明マグネシウム合金部材においてプレス加工が実質的に施されていない箇所などは、展伸材と同様の組織を実質的に維持することから、上述のように微細で均一的な大きさの上記金属間化合物が存在する組織を有する。   In the bonding material of the present invention using an expanded material in which an intermetallic compound containing Al and Mg or an intermetallic compound containing Al and Mn is present, the press work is substantially performed in a portion other than the bonding region, or in the magnesium alloy member of the present invention. The part which is not applied to the surface substantially maintains the same structure as the wrought material, and therefore has a structure in which the intermetallic compound having a fine and uniform size exists as described above.

[特性]
本発明鋳造材、鋳造コイル材、展伸材、接合材、及びマグネシウム合金部材(以下、まとめて本発明材と呼ぶことがある)は、Caを特定量含有することで、いずれも発火温度が高い。Caの含有量が多いほど発火温度も高く、例えば、600℃以上、更に650℃以上である。 [Characteristic]
The present cast material, cast coil material, wrought material, bonding material, and magnesium alloy member (hereinafter sometimes collectively referred to as the present invention material) contain a specific amount of Ca, all of which have an ignition temperature. high. The higher the Ca content, the higher the ignition temperature, for example, 600 ° C or higher, and further 650 ° C or higher.

本発明材は、連続鋳造を行っていること、また、この連続鋳造材を素材に用いていることに加えて、Alを特定量含有することで機械的特性にも優れ、例えば、引張強さが大きい。特に、連続鋳造材に展伸加工を施した本発明展伸材は、引張強さが更に高く、組成にもよるが、例えば、300MPa以上を満たす形態とすることができる。   The material of the present invention is continuously cast, and in addition to using this continuous cast material as a material, it also has excellent mechanical properties by containing a specific amount of Al, for example, tensile strength Is big. In particular, the wrought material of the present invention obtained by subjecting a continuous cast material to a drawing process has a higher tensile strength and can have a form satisfying, for example, 300 MPa or more, depending on the composition.

[形状]
(鋳造材、鋳造コイル材)
本発明鋳造材の代表的な形状は、平面が矩形状の板状材が挙げられる。連続鋳造後に適宜切断することで、比較的長さが短い鋳造シート材としたり、切断せず、例えば、長さが10m以上、更に50m以上、特に100m以上の長尺材とすることもできる。長尺材を巻き取ることで本発明鋳造コイル材が得られる。 [shape]
(Casting material, Casting coil material)
A typical shape of the cast material of the present invention is a plate-like material having a rectangular plane. By appropriately cutting after continuous casting, it is possible to obtain a cast sheet material having a relatively short length, or without cutting, for example, a long material having a length of 10 m or more, further 50 m or more, particularly 100 m or more. The cast coil material of the present invention is obtained by winding the long material.

本発明鋳造材の厚さは、10mm以下、更に7mm以下、特に5mm以下であると、厚さ方向に均一的な速度で急冷し易く、DASや金属間化合物を十分に小さくし易い。また、鋳造コイル材の場合、板状材の厚さが10mm以下であることで巻き取り易い。   When the thickness of the cast material of the present invention is 10 mm or less, more preferably 7 mm or less, particularly 5 mm or less, it is easy to rapidly cool at a uniform rate in the thickness direction, and DAS and intermetallic compounds can be made sufficiently small. Moreover, in the case of a cast coil material, it is easy to wind up because the thickness of a plate-shaped material is 10 mm or less.

本発明鋳造材の幅は、適宜選択することができる。上述のように接合材とすることで容易に広幅の展伸材を製造できるため、幅が狭いものでもよい。本発明鋳造材の幅は、100mm〜300mm程度とすると製造し易いと期待される。   The width of the cast material of the present invention can be appropriately selected. Since a wide expanded material can be easily manufactured by using a bonding material as described above, a material having a small width may be used. When the width of the cast material of the present invention is about 100 mm to 300 mm, it is expected to be easy to manufacture.

(展伸材)
本発明展伸材の代表的な形状は、平面が矩形状の板状材が挙げられる。上述の鋳造シート材を素材とした場合、比較的長さが短い展伸シート材が得られ、鋳造コイル材を素材とした場合、展伸コイル材や適宜切断して展伸シート材が得られる。また、所望の形状に打ち抜きなどを行うことで、所望の平面形状の展伸材とすることができる。 (Spread)
A typical shape of the wrought material of the present invention is a plate-like material having a rectangular plane. When the above-mentioned cast sheet material is used as a raw material, a relatively short stretched sheet material is obtained. When a cast coil material is used as a raw material, a stretched coil material or a stretched sheet material is obtained by appropriate cutting. . Moreover, it can be set as the wrought material of a desired planar shape by stamping etc. to a desired shape.

本発明展伸材の厚さは、5mm以下、更に3mm以下、特に1mm以下であると、薄型で軽量な塑性加工材(代表的には、プレス加工材)を製造できる。また、このように薄くすることで摩擦撹拌接合により接合し易く、接合材の生産性の向上に寄与することができる。   When the thickness of the wrought material of the present invention is 5 mm or less, further 3 mm or less, particularly 1 mm or less, a thin and light plastic work material (typically, a press work material) can be produced. Moreover, by making it thin in this way, it is easy to join by friction stir welding, and it can contribute to the improvement of productivity of a joining material.

本発明展伸材の幅は、適宜選択することができる。幅が細い展伸材を複数用意して摩擦撹拌接合により広幅(例えば、1000mm以上、更に2000mm以上)の展伸材とすることができる。   The width of the wrought material of the present invention can be appropriately selected. A plurality of wrought materials having a small width are prepared, and a wrought material having a wide width (for example, 1000 mm or more, further 2000 mm or more) can be obtained by friction stir welding.

(マグネシウム合金部材)
本発明マグネシウム合金部材は、少なくとも一部にプレス加工が施された塑性加工材であり、加工形態により種々の形状を取り得る。 (Magnesium alloy member)
The magnesium alloy member of the present invention is a plastically processed material that is at least partially pressed, and can take various shapes depending on the processing form.

[製造方法]
(準備工程)
まず、Alを2質量％以上11質量％以下、かつCaを0.1質量％以上10質量％以下含有し、残部Mg及び不純物からなるマグネシウム合金、又はAl,Caに加えて上述の添加元素を所望の量含有し、残部Mg及び不純物からなるマグネシウム合金の溶湯を用意する。代表的には、ベース組成のインゴットを溶解したベース溶湯に、所望の添加元素を溶解することで、所望の組成の溶湯を作製できる。特に、本発明のようにCaを特定の範囲で含有する鋳造材を作製する場合には、上記ベース溶湯に対して所望の量のCaを一度に溶解するのではなく、多段階に分けて溶解すると、所望の量のCaを均一的に混合でき、Caの偏在を防止できる。その結果、溶湯を均一的に急冷することができ、DASや金属間化合物を十分に小さくすることができる。 [Production method]
(Preparation process)
First, Al is contained in an amount of 2% by mass to 11% by mass and Ca is contained in an amount of 0.1% by mass to 10% by mass. Prepare a magnesium alloy melt containing the remaining amount of Mg and impurities. Typically, a melt having a desired composition can be produced by dissolving a desired additive element in a base melt obtained by dissolving an ingot having a base composition. In particular, when producing a cast material containing Ca in a specific range as in the present invention, a desired amount of Ca is not dissolved at once in the base molten metal, but is dissolved in multiple stages. Then, a desired amount of Ca can be uniformly mixed, and uneven distribution of Ca can be prevented. As a result, the molten metal can be cooled rapidly and DAS and intermetallic compounds can be made sufficiently small.

具体的には、所定量の一部のCaを含むCa含有溶湯を作製し、この溶湯に残部のCaを更に追加して所望の量のCaを含有する溶湯を作製する。上記Ca含有溶湯は、例えば、ベース組成のインゴットとして、例えば、所定量の全量の1質量％〜90質量％のCaを含むものを用意して溶解したり、ベース組成のインゴットとしてCaを含有しないものを用意し(当該インゴット中のCaの含有量は予め測定しておく)、このインゴットの溶解時に所望の量となるようにCaを同時に溶解して作製したりすることが挙げられる。Ca含有溶湯を利用することで、溶湯から不純物を除去する際や成分調整の際などで溶湯の燃焼を防止でき、酸化物の生成の低減といった効果も奏する。また、Caを多段階で混合することで、(1)正確な成分調整が行い易い、(2)品質の安定などといった効果も奏する。上記Ca含有溶湯に残部のCaを混合する場合、1度に混合してもよいが、更に多段階に分けて混合してもよい。上記Ca含有溶湯に対しても複数回に分けて残部のCaを混合することで、成分調整をより正確に行い易い。この場合、各回のCaの混合量を均等な量としてもよいし、異ならせてもよい。   Specifically, a Ca-containing molten metal containing a predetermined amount of a part of Ca is prepared, and the remaining Ca is further added to the molten metal to prepare a molten metal containing a desired amount of Ca. The Ca-containing molten metal is prepared, for example, as an ingot of a base composition, for example, by preparing and melting one containing 1% by mass to 90% by mass of Ca of a predetermined amount, or does not contain Ca as an ingot of a base composition It may be prepared by preparing a product (the Ca content in the ingot is measured in advance) and dissolving Ca simultaneously so as to obtain a desired amount when the ingot is dissolved. By using the Ca-containing molten metal, combustion of the molten metal can be prevented when impurities are removed from the molten metal or when components are adjusted, and the effect of reducing the formation of oxides is also achieved. Further, by mixing Ca in multiple stages, there are effects such as (1) easy accurate component adjustment and (2) stable quality. When the remainder of Ca is mixed with the Ca-containing molten metal, it may be mixed at once, but may be further divided into multiple stages. It is easy to adjust the component more accurately by mixing the remaining Ca with the Ca-containing molten metal in a plurality of times. In this case, the mixing amount of Ca at each time may be equal or different.

上記溶解は、酸化物の生成を低減するために、酸素濃度が低い雰囲気(5体積％以下)、或いは酸素を実質的に含有しない雰囲気、例えば、窒素やアルゴンといった不活性ガス雰囲気、二酸化炭素雰囲気、不活性ガスと二酸化炭素との混合雰囲気などで行うことが好ましい。   In order to reduce the formation of oxides, the above-mentioned dissolution is performed in an atmosphere with a low oxygen concentration (5% by volume or less), or an atmosphere that does not substantially contain oxygen, for example, an inert gas atmosphere such as nitrogen or argon, a carbon dioxide atmosphere It is preferable to carry out in a mixed atmosphere of an inert gas and carbon dioxide.

(鋳造工程)
本発明製造方法では、急冷凝固が可能な連続鋳造法を利用する。また、本発明鋳造材は、代表的には板状材とすることから、連続鋳造法として、板状材の鋳造に適した双ロール鋳造法や双ベルト鋳造法などを利用する。特に、可動鋳型として一対の鋳造ロールを具える双ロール鋳造法は、剛性及び熱伝導性に優れ、熱容量が大きい鋳型を用いることで急冷凝固が可能で、冷却速度を大きくし易い上に、偏析が少なく、従来のダイカスト材やチクソモールド材と比較して高強度・高硬度な鋳造材を形成できて好ましい。 (Casting process)
In the manufacturing method of the present invention, a continuous casting method capable of rapid solidification is used. Further, since the cast material of the present invention is typically a plate-like material, a twin roll casting method or a twin belt casting method suitable for casting of the plate-like material is used as a continuous casting method. In particular, the twin roll casting method, which has a pair of casting rolls as a movable mold, is excellent in rigidity and thermal conductivity, can be rapidly solidified by using a mold having a large heat capacity, can easily increase the cooling rate, and is segregated. Therefore, it is preferable because it can form a cast material having a high strength and a high hardness as compared with conventional die casting materials and thixo mold materials.

そして、本発明製造方法では、鋳造時の冷却速度を650℃/秒以上とすることを最大の特徴とする。上記冷却速度が大きいほどDASや種々の金属間化合物の成長を抑制して、微細にし易い。従って、冷却速度は、1000℃/秒以上、更に1500℃/秒以上、特に2000℃/秒以上が好ましく、上限は特に設けないが、量産体制では1000℃/秒〜5000℃/秒程度が利用し易い。冷却速度は、例えば、AZ系合金については、一般的なMg-Al-Zn系合金において成立する以下の式を利用して決定する。種々の組成や仕様(厚さ、幅など)のテストピースを用いて、DAS:dと冷却速度:Vとの関係を予め求めて、相関データを作成しておき、この相関データを参照して、所望のDASとなるように冷却速度を調整すると、作業性に優れる。
dをDAS(μm)、冷却速度(℃/秒)をVとするとき、d＝35.5×V^-0.31。
なお、AZ系合金以外の組成のマグネシウム合金については、α,βを組成(合金種)による定数、d'をDAS(μm)とするとき、d'＝α×V’^-βで表わされる式により冷却速度:V’を求めるとよい。 The production method of the present invention is characterized in that the cooling rate during casting is 650 ° C./second or more. The higher the cooling rate, the more easily the growth can be achieved by suppressing the growth of DAS and various intermetallic compounds. Accordingly, the cooling rate is 1000 ° C./second or more, more preferably 1500 ° C./second or more, particularly 2000 ° C./second or more, and there is no particular upper limit, but the mass production system uses about 1000 ° C./second to 5000 ° C./second. Easy to do. For example, for the AZ alloy, the cooling rate is determined by using the following equation that holds in a general Mg—Al—Zn alloy. Using test pieces with various compositions and specifications (thickness, width, etc.), obtain the relationship between DAS: d and cooling rate: V in advance, create correlation data, and refer to this correlation data. If the cooling rate is adjusted to achieve the desired DAS, the workability is excellent.
When d is DAS (μm) and the cooling rate (° C./sec) is V, d = 35.5 × V ^−0.31 .
For magnesium alloys with compositions other than AZ alloys, α and β are constants depending on the composition (alloy type), and d ′ is DAS (μm), and d ′ = α × ^V′−β The cooling rate: V ′ may be obtained by

冷却速度を上記特定の範囲とするには、例えば、鋳造ロールの温度を低くしたり、鋳造ロールの周速を遅くしたり、ロール荷重を大きくしたりすることが挙げられる。つまり、鋳造ロール自体の脱熱能力を高めたり、溶湯と鋳造ロールとの接触時間を長くしたり、溶湯が鋳造ロールに十分に接触できるようにしたりして、ノズルから排出された溶湯が鋳造ロールにより十分に冷却されるようにすることが挙げられる。   In order to set the cooling rate within the specific range, for example, the temperature of the casting roll is lowered, the peripheral speed of the casting roll is lowered, or the roll load is increased. In other words, the heat discharged from the nozzle is increased by increasing the heat removal capacity of the casting roll itself, increasing the contact time between the molten metal and the casting roll, or allowing the molten metal to sufficiently contact the casting roll. To be sufficiently cooled.

特に、図4に示すように、一対の鋳造ロール100間のギャップ(一対の鋳造ロール100間が最も近接した箇所:ギャップ位置p_gの間隔)をg_r、鋳造ロール100に向かって溶湯を排出するノズル200の開口部220の間隔をg_nとするとき、g_n＜g_rとなるように、ノズル200の間隔g_n及び鋳造ロール100のギャップg_rの少なくとも一方を調整すると冷却速度を大きく(速く)し易い。 In particular, as shown in FIG. 4, a pair of casting between rolls 100 Gap: discharging the molten metal towards the (portion between the pair of casting rolls 100 closest spacing gap position p _g) g _r, the casting rolls 100 to when the distance between the opening 220 of the nozzle 200 and g _n, such that the g _n <g _r, increasing the cooling rate adjusting at least one of the spacing g _n and gap g _r of the casting roll 100 of the nozzle 200 Easy to (fast).

図4(A)に示すように、ノズル200を構成する一対のノズル本体210の外表面間の間隔が大きい場合(ノズル200の全体厚さが厚い場合)、g_n＜g_rを満たすようにノズル200の間隔g_nを調整すると、ノズル本体210の厚さを厚くできる。そのため、ノズル本体210の断熱性を高められることから、ノズル200の開口部220から排出される溶湯は、鋳造ロール100の近傍まで高温に維持されて、鋳造ロール100に接触して冷却される。従って、ギャップ位置p_gの溶湯の温度を高められることから、冷却速度を大きくすることができる。ノズル本体210は、公知の材料により構成することができる。 4 as shown in (A), (if the overall thickness of the nozzle 200 is thick) when the interval between the outer surfaces of the pair of the nozzle body 210 constituting the nozzle 200 is large, so as to satisfy g _n <g _r By adjusting the interval g _{n of the} nozzles 200, the thickness of the nozzle body 210 can be increased. Therefore, since the heat insulation of the nozzle body 210 can be improved, the molten metal discharged from the opening 220 of the nozzle 200 is maintained at a high temperature up to the vicinity of the casting roll 100 and is cooled by contacting the casting roll 100. Therefore, since the temperature of the molten metal at the gap position p _g can be increased, the cooling rate can be increased. The nozzle body 210 can be made of a known material.

或いは、図4(B)に示すようにノズル200を構成する一対のノズル本体210の外表面間の間隔が狭い場合(ノズル200の全体厚さが薄い場合)、鋳造ロール100のギャップ位置p_gにノズル200自体を近接して配置できる。そのため、ノズル200の開口部220から排出された溶湯は、鋳造ロール100に接触するまでの距離が短いことから、鋳造ロール100に直ちに接触して冷却される。従って、ギャップ位置p_gの溶湯の温度を高められることから、冷却速度を大きくすることができる。 Alternatively, as shown in FIG. 4B, when the distance between the outer surfaces of the pair of nozzle bodies 210 constituting the nozzle 200 is narrow (when the overall thickness of the nozzle 200 is thin), the gap position p _{g of the} casting roll 100 The nozzle 200 itself can be arranged close to the nozzle. Therefore, since the molten metal discharged from the opening 220 of the nozzle 200 has a short distance until it contacts the casting roll 100, it immediately contacts the casting roll 100 and is cooled. Therefore, since the temperature of the molten metal at the gap position p _g can be increased, the cooling rate can be increased.

具体的なノズル200の間隔g_nは、g_n＝0.8×g_r〜0.95×g_rが挙げられる。なお、鋳造ロール間のギャップは、鋳造材の厚さを決定する因子となるため、調整には限界があるが、ノズルの間隔は比較的変化させ易い。 Specific examples of the gap g _n between the nozzles 200 include g _n = 0.8 × g _{r to} 0.95 × g _r . Since the gap between the casting rolls is a factor that determines the thickness of the cast material, there is a limit to the adjustment, but the interval between the nozzles is relatively easy to change.

鋳造ロールから排出された鋳造材は、適宜な長さに切断することで鋳造シート材を製造でき、切断せずに長尺材を巻き取ることで鋳造コイル材を製造できる。長尺材を巻き取るにあたり、鋳造材において巻き取り直前の箇所を加熱したり保温したりなどして150℃以上となるようにして巻き取ることで、コイルの内径(巻き取り径)が小さい場合などでも、割れなどを生じることなく巻き取れる。   The cast material discharged from the casting roll can be cut into an appropriate length to produce a cast sheet material, and the cast coil material can be produced by winding the long material without cutting. When winding the long material, the inner diameter (winding diameter) of the coil is small by winding the cast material to 150 ° C or higher by heating or keeping the part immediately before winding. Can be wound without cracking.

(溶体化工程)
本発明鋳造材を素材として、圧延などの展伸加工を施して本発明展伸材を製造する場合、展伸加工前に溶体化処理を施すと、組成を均質化したり、Alといった元素を固溶させることができて好ましい。溶体化処理は、添加元素の種類や含有量にもよるが、保持温度:350℃以上、特に、保持温度:380℃〜420℃、保持時間:60分〜2400分(1時間〜40時間)とすることが好ましい。保持時間は、Alといった添加元素の含有量が多いほど長くすることが好ましい。上記保持時間からの冷却工程において、水冷や衝風といった強制冷却などを利用して、冷却速度を速めると(好ましくは1℃/min以上、より好ましくは50℃/min以上)、粗大な析出物(代表的には金属間化合物)の析出を抑制することができて好ましい。 (Solution process)
When manufacturing the wrought product of the present invention by subjecting the cast material of the present invention to a rolling process such as rolling, if a solution treatment is performed before the stretching process, the composition is homogenized or an element such as Al is fixed. It is preferable because it can be dissolved. Solution treatment depends on the type and content of the additive element, but holding temperature: 350 ° C or higher, especially holding temperature: 380 ° C to 420 ° C, holding time: 60 minutes to 2400 minutes (1 hour to 40 hours) It is preferable that The holding time is preferably increased as the content of additive elements such as Al increases. In the cooling process from the above holding time, if the cooling rate is increased by using forced cooling such as water cooling or blast (preferably 1 ° C / min or more, more preferably 50 ° C / min or more), coarse precipitates This is preferable because precipitation of (typically intermetallic compounds) can be suppressed.

(展伸工程)
本発明鋳造材や、上記溶体化処理を施した処理材に圧延、押出、鍛造などの展伸加工を施すにあたり、素材(圧延途中のものを含む)を加熱することで加工性を高められるため、少なくとも1回(1パス)は温間加工とする。特に、本発明鋳造材は、Caを含有することで加工性に劣ることから、複数回(多パス)を温間加工とすることが好ましい。但し、素材の加熱温度が高過ぎると、析出物の過度な成長や過度の析出を招いたり、素材の焼き付きが発生したり、素材の結晶粒が粗大化して得られた展伸材の機械的特性が低下したりする。そのため、温間展伸加工における素材の加熱温度は、400℃以下、更に350℃以下が好ましい。特に、素材の加熱温度が300℃超の加工と、300℃以下の加工とを組み合せて行い、300℃超の加工をできるだけ少なくすること(好ましくは、溶体化処理以降、素材が300℃超に保持される時間の総合計が6時間以下、より好ましくは1時間程度にすること)が好ましい。300℃以下の加工は、素材の加熱温度を100℃以上280℃以下とすることがより好ましい。 (Stretching process)
In performing the extension processing such as rolling, extrusion, forging and the like to the cast material of the present invention and the above-mentioned solution-treated material, workability can be improved by heating the raw materials (including those in the middle of rolling). At least once (1 pass) is warm working. In particular, since the cast material of the present invention is inferior in workability due to containing Ca, it is preferable to perform warm processing multiple times (multiple passes). However, if the heating temperature of the material is too high, it will cause excessive growth and precipitation of precipitates, seizure of the material, and the mechanical properties of the wrought material obtained by coarsening the crystal grains of the material. The characteristics are degraded. Therefore, the heating temperature of the raw material in the warm extension processing is preferably 400 ° C. or lower, and more preferably 350 ° C. or lower. In particular, processing with a heating temperature of the material exceeding 300 ° C and processing at 300 ° C or less should be combined to minimize the processing above 300 ° C (preferably, after the solution treatment, the material will exceed 300 ° C. It is preferable that the total time of the retention time is 6 hours or less, more preferably about 1 hour). In the processing at 300 ° C. or lower, it is more preferable that the heating temperature of the material is 100 ° C. or higher and 280 ° C. or lower.

展伸加工が例えば圧延の場合、多パスの圧延を施すことで、所望の板厚にできると共に、素材の平均結晶粒径を小さくしたり(例えば、30μm以下、更に20μm以下、特に10μm以下、好ましくは5μm以下)、圧延やプレス加工といった塑性加工性を高められる。圧延は、公知の条件を利用できる。例えば、素材だけでなく圧延ロールも加熱すると、加工性をより高められる。また、仕上げ圧延などで圧下率が小さい圧延では、冷間で圧延を施してもよい。圧延のパス数、1パスあたりの加工度、総加工度、後述する圧延途中や圧延後の熱処理などの条件は、所望の厚さや所望の特性(引張強さなど)を有する展伸材(圧延材)が得られるように適宜選択することができる。圧延材の幅も適宜選択することができ、広幅のものを作製して適宜切断して、所望の幅としてもよいし、摩擦撹拌接合により接合することで広幅材にできるため、細幅の圧延材としてもよい。   In the case of rolling, for example, rolling, by applying multi-pass rolling, it is possible to achieve a desired plate thickness and reduce the average crystal grain size of the material (for example, 30 μm or less, further 20 μm or less, especially 10 μm or less, Preferably, the plastic workability such as rolling or pressing is improved. For the rolling, known conditions can be used. For example, when not only a raw material but a rolling roll is heated, workability can be improved more. In rolling with a small rolling reduction such as finish rolling, the rolling may be performed cold. Conditions such as number of rolling passes, degree of processing per pass, total degree of processing, heat treatment after rolling or after rolling, which will be described later, have a desired thickness and desired properties (such as tensile strength). Material) can be selected as appropriate. The width of the rolled material can also be selected as appropriate. A wide width can be produced and cut as appropriate to obtain a desired width, or a wide width material can be obtained by joining by friction stir welding. It is good also as a material.

多パスの圧延を行う場合、パス間に中間熱処理を行ってもよい。中間熱処理を行うことで、当該熱処理までの圧延により加工対象である素材に導入された歪みや残留応力、集合組織などを除去、軽減できる。その結果、当該熱処理後の圧延で不用意な割れや歪み、変形を防止でき、より円滑に圧延を行える。中間熱処理の保持温度も、350℃以下、更に300℃以下、特に250℃以上280℃以下とすると、上記析出物の成長や結晶粒の粗大化などを防止できて好ましい。保持時間は、20分〜60分が挙げられる。   When performing multi-pass rolling, intermediate heat treatment may be performed between passes. By performing the intermediate heat treatment, it is possible to remove or reduce strain, residual stress, texture, and the like introduced into the material to be processed by rolling up to the heat treatment. As a result, inadvertent cracking, distortion, and deformation can be prevented by rolling after the heat treatment, and rolling can be performed more smoothly. The holding temperature of the intermediate heat treatment is preferably 350 ° C. or lower, more preferably 300 ° C. or lower, and particularly preferably 250 ° C. or higher and 280 ° C. or lower. This is preferable because growth of the precipitates and coarsening of crystal grains can be prevented. Examples of the retention time include 20 minutes to 60 minutes.

(展伸加工後の加工・処理)
上記展伸材に、加工により導入された歪みの除去などを目的として最終熱処理(最終焼鈍)を施すことができる。或いは、展伸材が圧延材である場合、最終熱処理を施さず矯正加工を施すことができる。矯正加工が施された矯正材にプレス加工といった塑性加工を施す場合、塑性加工時に動的再結晶化が生じることで塑性加工性に優れる。矯正加工は、圧延材を100℃〜300℃、好ましくは150℃以上280℃以下に加熱して行う温間矯正が挙げられる。温間矯正には、圧延材を加熱可能な加熱炉と、加熱された圧延材に連続的に曲げ(歪)を付与するために複数のロールが上下に対向して千鳥状に配置されたロール部とを具えるロールレベラ装置を好適に利用できる。上記ロールレベラ装置により、圧延材は上記加熱炉内に導入されて加熱されながら上記ロール部に送られ、ロール部の上下のロール間を通過するごとに、これらのロールにより順次曲げが付与される。 (Processing / processing after stencil processing)
The wrought material can be subjected to a final heat treatment (final annealing) for the purpose of removing strain introduced by processing. Alternatively, when the wrought material is a rolled material, it can be straightened without being subjected to final heat treatment. When plastic processing such as press processing is performed on the straightened material that has been subjected to straightening processing, dynamic recrystallization occurs during the plastic working, and thus the plastic workability is excellent. The straightening process includes warm straightening performed by heating the rolled material to 100 ° C to 300 ° C, preferably 150 ° C to 280 ° C. For warm correction, a heating furnace that can heat the rolled material, and a roll in which a plurality of rolls are arranged in a staggered manner facing each other in order to continuously bend (strain) the heated rolled material A roll leveler device comprising a portion can be suitably used. The rolled material is introduced into the heating furnace by the roll leveler device and is sent to the roll part while being heated. Each time the rolled material passes between the upper and lower rolls of the roll part, the rolls are sequentially bent.

その他、上記圧延材や最終熱処理が施された熱処理材、矯正材に研磨を施してもよい。研磨は、研磨粉の飛散防止のため、湿式研磨が好ましい。特に、ベルト研磨は、板状材に対して連続的に研磨を施すことができ、作業性に優れる。   In addition, the rolled material, the heat-treated material subjected to the final heat treatment, and the straightening material may be polished. The polishing is preferably wet polishing in order to prevent scattering of the polishing powder. In particular, belt polishing can continuously polish a plate-like material, and is excellent in workability.

(接合)
素材として上記本発明展伸材(代表的には圧延材。その他、圧延材に上述した最終熱処理や矯正、研磨を施したものでもよい)を複数用意し、これら展伸材を摩擦撹拌接合により接合することで、摩擦撹拌接合による接合領域を有する本発明接合材が得られる。 (Joining)
Prepare a plurality of the above-mentioned wrought materials of the present invention (typically rolled materials. In addition, the rolled materials may be subjected to the above-mentioned final heat treatment, correction, and polishing), and these wrought materials are prepared by friction stir welding. By joining, this invention joining material which has the joining area | region by friction stir welding is obtained.

接合にあたり、接合する素材の端面にそれぞれにエッジ加工を施して、当該素材の表面と端面とがなす角が直角となるようにする。このようなエッジ加工を施すことで、接合する素材の端面同士を精度良く接触でき、良好に接合することができる。摩擦撹拌接合には、工具鋼や超硬合金といった硬質材から構成され、撹拌に利用される小径部と装置本体に取り付けられる大径部とを具える接合用プローブを利用する。特に、厚さ3mm以下、更に1mm以下といった薄い板状材同士を接合する場合、接合用プローブの小径部の先端径:3mm〜6mm、小径部の高さ:接合する板状材の厚さの60％〜100％、大径部における小径部側の径:8mm〜15mm、小径部及び大径部において先端面と側面とがなす角:90°〜150°といったプローブが好適に利用できる。接合条件は、プローブの回転数:500r.p.m〜5000r.p.m、送り速度:0.1m/min〜1.0m/min、押込量:接合する板状材の厚さの60％〜100％、プローブの角度:プローブ送り方向とプローブ中心軸とのなす角が90°〜96°、隣り合う一対の板状材の並列方向(板状材同士を接触することで形成される境界線に対して直交方向)とプローブの中心軸とがなす角が90°が挙げられる。   At the time of joining, edge processing is performed on the end surfaces of the materials to be joined so that the angle formed by the surface of the materials and the end surfaces becomes a right angle. By performing such edge processing, the end surfaces of the materials to be joined can be brought into contact with each other with high accuracy and can be joined well. The friction stir welding uses a joining probe that is made of a hard material such as tool steel or cemented carbide and has a small-diameter portion used for stirring and a large-diameter portion attached to the apparatus main body. In particular, when joining thin plate-like materials with a thickness of 3 mm or less, further 1 mm or less, the tip diameter of the small diameter part of the probe for bonding: 3 mm to 6 mm, the height of the small diameter part: the thickness of the plate material to be joined Probes such as 60% to 100%, the diameter on the small diameter part side in the large diameter part: 8 mm to 15 mm, and the angle between the tip surface and the side surface in the small diameter part and the large diameter part: 90 ° to 150 ° can be suitably used. Joining conditions are: probe rotation speed: 500 rpm to 5000 rpm, feed speed: 0.1 m / min to 1.0 m / min, pushing amount: 60% to 100% of the thickness of the plate to be joined, Angle: Angle between the probe feed direction and the center axis of the probe is 90 ° to 96 °, parallel direction of a pair of adjacent plate materials (perpendicular to the boundary line formed by contacting the plate materials) ) And the central axis of the probe is 90 °.

複数の素材を接合する場合、上記接合用プローブを複数用意して、同時に複数箇所の接合を行うと接合時間が短く接合作業性に優れ、一つの接合用プローブで行う場合、設備を簡素化できる。   When joining a plurality of materials, preparing a plurality of the above-mentioned joining probes and joining them at a plurality of locations at the same time shortens the joining time and excels in workability. When using a single joining probe, the equipment can be simplified. .

(塑性加工)
素材として上記本発明展伸材や上記本発明接合材を用意し、これら素材にプレス加工、曲げ加工、鍛造などといった塑性加工を施すことで、塑性加工材が得られる。プレス加工を施した場合、本発明マグネシウム合金部材が得られる。塑性加工を施す場合も、素材を加熱すると塑性加工性を高められるが、高過ぎると焼付きなどの問題があるため、素材の加熱温度は500℃以下が好ましい。加工度によっては室温としてもよい。特に、素材の加熱温度を200℃〜300℃とすると、素材の塑性加工性を十分に高められる上に、焼き付などを防止し易い。上記塑性加工後に更に熱処理を施して、塑性加工により導入された歪みや残留応力の除去、機械的特性の向上を図ることができる。この熱処理条件は、加熱温度:100℃〜300℃、加熱時間:5分〜60分程度が挙げられる。 (Plastic processing)
The above stretched material of the present invention or the above bonded material of the present invention is prepared as a material, and a plastically worked material is obtained by subjecting these materials to plastic working such as pressing, bending, forging, and the like. When the press working is performed, the magnesium alloy member of the present invention is obtained. Even when plastic working is performed, the plastic workability can be improved by heating the raw material, but if it is too high, there is a problem such as seizure, so the heating temperature of the raw material is preferably 500 ° C. or lower. It may be room temperature depending on the degree of processing. In particular, when the heating temperature of the raw material is set to 200 ° C. to 300 ° C., the plastic workability of the raw material can be sufficiently improved and seizure can be easily prevented. Further heat treatment can be performed after the plastic working to remove strain and residual stress introduced by the plastic working and improve the mechanical characteristics. Examples of the heat treatment conditions include a heating temperature: 100 ° C. to 300 ° C. and a heating time: about 5 minutes to 60 minutes.

(その他の加工・処理)
その他、上記展伸材や塑性加工材に防食処理(陽極酸化処理、化成処理)、塗装などを施すことで、耐食性の向上、美観・商品価値の向上などを図ることができる。防食処理を施した展伸材に塑性加工を施すこともできる。 (Other processing / processing)
In addition, by applying anticorrosion treatment (anodic oxidation treatment, chemical conversion treatment), coating, etc. to the wrought material or plastic work material, it is possible to improve corrosion resistance, aesthetics, and commercial value. It is also possible to perform plastic working on the wrought material subjected to anticorrosion treatment.

以下、本発明のより具体的な実施の形態を説明する。
[試験例1]
種々の組成のマグネシウム合金からなる鋳造材を作製し、その金属組織を調べた。 Hereinafter, more specific embodiments of the present invention will be described.
[Test Example 1]
Cast materials made of magnesium alloys of various compositions were prepared and their metal structures were examined.

AZ91合金相当のAlを含有する組成(Mg-9.0％Al-1.0％Zn-0.23％Mn(全て質量％))のマグネシウム合金をベース合金とし、表1に示す量のCaを含有する鋳造材を作製した。Caを含有する鋳造材は、ベース合金のインゴットの溶解時、表1に示す量の一部のCaも同時に溶解してCa含有溶湯を作製し、得られたCa含有溶湯に残部のCaを添加して、所望の組成の溶湯を用意した。Caを含有していない鋳造材は、ベース合金のインゴットを溶解した溶湯を用意した。   A cast material containing a magnesium alloy with a composition equivalent to AZ91 alloy (Mg-9.0% Al-1.0% Zn-0.23% Mn (all mass%)) and containing Ca in the amount shown in Table 1. Produced. When the base alloy ingot is melted, the Ca-containing cast material also dissolves a part of the amount of Ca shown in Table 1 to produce a Ca-containing molten metal, and the remaining Ca is added to the obtained Ca-containing molten metal. Thus, a molten metal having a desired composition was prepared. For the cast material containing no Ca, a molten metal in which a base alloy ingot was melted was prepared.

用意した各溶湯を双ロール連続鋳造機により連続鋳造して厚さ:4.1mm〜4.2mm、幅:290mm鋳造材(鋳造板)を作製し、この鋳造材を巻き取って、鋳造コイル材を作製した。鋳造時の冷却速度を表1に示す。冷却速度は、ロール周速や鋳造ロールの温度を調整することで変化させた。ロール周速が遅いほど、又は鋳造ロールの温度が低いほど、冷却速度を大きく(速く)することができる。また、この試験ではいずれの試料についても、鋳造ロール間のギャップをg_r、ノズルの開口部の間隔をg_nとするとき、ノズルの間隔g_nがギャップg_rよりも小さくなるようにノズルの間隔g_nを調整した(ここではg_n≒0.9g_r)。 Each prepared molten metal is continuously cast by a twin roll continuous casting machine to produce a cast material (thickness: 4.1mm to 4.2mm, width: 290mm), and this cast material is wound to produce a cast coil material. did. Table 1 shows the cooling rate during casting. The cooling rate was changed by adjusting the roll peripheral speed and the temperature of the casting roll. The slower the roll peripheral speed or the lower the temperature of the casting roll, the greater (faster) the cooling rate. Also, in this test, for any sample, when the gap between the casting rolls is g _r and the gap between the nozzle openings is g _n , the nozzle gap g _n is smaller than the gap g _r . The interval g _n was adjusted (here, g _n ≈0.9 g _r ).

得られた各鋳造コイル材を巻き戻して、適宜な長さに切断した試験片を作製した。各試験片の横断面(上記コイル材の長手方向と直交方向の断面)をSEM-EDX(走査型電子顕微鏡-エネルギー分散型X線分光法)を用いて観察及び分析した。SEM観察像(5000倍)を図1(A),図3(A)に示す。図3(A)に示すようにCaを含有していないAZ91合金相当の鋳造材:試料No.100は、組織全体に亘って微細な金属間化合物が分散して存在することが分かる。一方、図1(A)に示すようにCaを含有する鋳造材:試料No.1-22は、網目状に繋がって金属間化合物が存在していることが分かる。また、この網目は、図1(A)に示すように色が異なる金属間化合物、具体的には白みがかったものと灰色がかったものという、異種の金属間化合物同士が隣接して形成されていることが分かる。この断面をX線回折したところ、Al₂CaといったAlとCaとを含む金属間化合物と、Al₁₂Mg₁₇といったAlとMgとを含む金属間化合物とを含有すること、即ち、異種の金属間化合物が存在することを確認した。また、これらの金属間化合物は、デンドライト組織のアーム間に実質的に晶出していることを確認した。 Each of the obtained cast coil materials was rewound to prepare a test piece cut to an appropriate length. The cross section of each test piece (the cross section in the direction perpendicular to the longitudinal direction of the coil material) was observed and analyzed using SEM-EDX (scanning electron microscope-energy dispersive X-ray spectroscopy). SEM observation images (5000 times) are shown in FIGS. 1 (A) and 3 (A). As shown in FIG. 3 (A), it can be seen that in the cast material corresponding to the AZ91 alloy not containing Ca: sample No. 100, fine intermetallic compounds are dispersed throughout the entire structure. On the other hand, as shown in FIG. 1 (A), it can be seen that the cast material containing Ca: Sample No. 1-22 is connected in a network and an intermetallic compound is present. In addition, as shown in FIG. 1 (A), this mesh is formed by adjacent intermetallic compounds of different colors, specifically, whitish and grayish ones. I understand that X-ray diffraction of this cross section shows that it contains an intermetallic compound containing Al and Ca, such as Al ₂ Ca, and an intermetallic compound containing Al and Mg, such as Al ₁₂ Mg ₁₇ , that is, between different metals. The presence of the compound was confirmed. Further, it was confirmed that these intermetallic compounds were substantially crystallized between the arms of the dendrite structure.

上述のように断面(横断面)をとり、この断面を光学顕微鏡(400倍)により観察し、この観察像を用いてDASを測定した。ここでは、3個の断面をとって、断面ごとに一つの観察像をとり、3個の観察像においてDASを求め、その平均を表1に示す。   A cross section (transverse section) was taken as described above, this cross section was observed with an optical microscope (400 times), and DAS was measured using this observation image. Here, three cross sections are taken, one observation image is taken for each cross section, DAS is obtained from the three observation images, and the average is shown in Table 1.

上述のように断面(横断面)をとり、この断面のSEM観察像(5000倍)のFE-EPMA(電界放出型電子線マイクロアナライザ)による組成マッピングを行い、Caの濃度分布及びAlの濃度分布を調べた。図2(A)にCaの濃度分布、図2(B)にAlの濃度分布を示す。市販のEPMA装置によりカラーマッピングを行うと、CaやAlといった元素の含有量の大小を色別表示できる。なお、顕微鏡の観察倍率は適宜選択することができる。   Take a cross-section (transverse cross section) as described above, perform composition mapping with FE-EPMA (Field Emission Electron Microanalyzer) of SEM observation image (5000 times) of this cross section, Ca concentration distribution and Al concentration distribution I investigated. FIG. 2 (A) shows the Ca concentration distribution, and FIG. 2 (B) shows the Al concentration distribution. When color mapping is performed with a commercially available EPMA device, the content of elements such as Ca and Al can be displayed in different colors. The observation magnification of the microscope can be selected as appropriate.

図2に示すように、CaやAlは、デンドライト組織のアーム間に高濃度に存在すること、また、Caの高濃度部分とAlの高濃度部分とが概ね一致していることが分かる。上述したX線回折の結果を考慮しても、このCaの高濃度部分とAlの高濃度部分とは、Al₂CaといったAlとCaとを含む金属間化合物の結晶相である、と考えられる。 As shown in FIG. 2, it can be seen that Ca and Al are present in a high concentration between the arms of the dendrite structure, and that the high concentration portion of Ca and the high concentration portion of Al are substantially the same. Considering the above-mentioned X-ray diffraction results, the high-concentration portion of Ca and the high-concentration portion of Al are considered to be crystal phases of an intermetallic compound containing Al and Ca such as Al ₂ Ca. .

各試験片(鋳造材)について、AlとCaとを含む金属間化合物の最大径、AlとCaとを含む金属間化合物の最大径とDASとの差(絶対値)、AlとCaとを含む金属間化合物の最大径とDASとの和、AlとCaとを含む金属間化合物の平均粒径を調べた。その結果を表1に示す。上記金属間化合物の抽出は、走査型電子顕微鏡:SEMの反射電子像、エネルギー分散型X線分光法:EDXを利用することができる。抽出した各金属間化合物の輪郭内の面積から、この面積と等しい面積を有する当該金属間化合物の円相当径を求め、この円相当径を金属間化合物の粒径とする。ここでは、各試験片について、3個の断面(横断面)をとり、断面ごとに一つの観察像をとり、3個の観察像中に存在する全てのAlとCaとを含む金属間化合物の粒径を求め、3個の観察像中の粒径の最大値を最大径とした。平均粒径は、上述のように3個の観察像中に存在する全てのAlとCaとを含む金属間化合物の粒径を求め、その平均とした。但し、粒径が0.05μm以下の金属間化合物は、粒径の測定が困難であり、除外した(この点は、後述する試験例も同様である)。そのため、実質的な平均粒径は、表1に示す値よりも小さい。   For each test piece (cast material), the maximum diameter of the intermetallic compound containing Al and Ca, the difference between the maximum diameter of the intermetallic compound containing Al and Ca and DAS (absolute value), including Al and Ca The sum of the maximum intermetallic compound diameter and DAS, and the average particle diameter of intermetallic compounds containing Al and Ca were examined. The results are shown in Table 1. For the extraction of the intermetallic compound, a scanning electron microscope: SEM reflected electron image, energy dispersive X-ray spectroscopy: EDX can be used. From the area within the contour of each extracted intermetallic compound, the equivalent circle diameter of the intermetallic compound having an area equal to this area is obtained, and this equivalent circle diameter is defined as the particle diameter of the intermetallic compound. Here, for each test piece, take three cross-sections (transverse cross-section), take one observation image for each cross-section, of the intermetallic compound containing all Al and Ca present in the three observation images The particle diameter was determined, and the maximum value of the particle diameters in the three observation images was taken as the maximum diameter. As described above, the average particle size was obtained by calculating the particle size of an intermetallic compound containing all Al and Ca present in the three observed images. However, intermetallic compounds having a particle size of 0.05 μm or less were excluded because it was difficult to measure the particle size (this is the same in the test examples described later). Therefore, the substantial average particle diameter is smaller than the values shown in Table 1.

また、上記試験片の断面(横断面)において、表層領域及び中央領域の両領域から観察像をとり、各領域におけるAlとCaとを含む金属間化合物の最大径、平均粒径、両領域の平均粒径の差を求めた。表層領域は、上記試験片の表面からその厚さ方向に当該試験片の厚さ(4.1mm〜4.2mm)の20％までの領域、つまり表面から厚さ方向に0.82mm〜0.84mmまでの領域とし、中央領域は、当該試験片の厚さ方向の中心から表面に向かって当該試験片の厚さの±10％までの領域、つまり厚さ方向の中心を含む0.82mm〜0.84mmの領域とする。最大径及び平均粒径は、上述と同様にして求めた。但し、中央領域の観察像は、中心線偏析部を除く領域からとった。   In addition, in the cross section (cross section) of the test piece, take an observation image from both the surface layer region and the central region, the maximum diameter of the intermetallic compound containing Al and Ca in each region, the average particle size, The difference in average particle size was determined. The surface layer area is the area up to 20% of the thickness (4.1 mm to 4.2 mm) of the test piece in the thickness direction from the surface of the test piece, that is, the area from 0.82 mm to 0.84 mm in the thickness direction from the surface. The central region is a region up to ± 10% of the thickness of the test piece from the center in the thickness direction of the test piece toward the surface, that is, a region of 0.82 mm to 0.84 mm including the center in the thickness direction. To do. The maximum diameter and average particle diameter were determined in the same manner as described above. However, the observation image of the central region was taken from the region excluding the center line segregation part.

更に、AlとMgとを含む金属間化合物の平均粒径を測定した。この金属間化合物の平均粒径は、上述したAlとCaとを含む金属間化合物の平均粒径と同様にして測定した。その結果を表1に示す。   Furthermore, the average particle diameter of the intermetallic compound containing Al and Mg was measured. The average particle size of the intermetallic compound was measured in the same manner as the average particle size of the intermetallic compound containing Al and Ca described above. The results are shown in Table 1.

その他、上記鋳造コイル材を巻き戻して適宜切断して、JIS 13B号の板状試験片(JIS Z 2201(1998)))を作製し、JIS Z 2241(1998)の金属材料引張試験方法に基づいて、室温(20℃〜25℃程度)で鋳造方向に沿って引張試験(標点距離GL=50mm、引張速度:5mm/min)を行い、引張強さ(MPa)及び伸び(％)を測定した。その結果を表1に示す(n＝5の最小値)。   In addition, the above cast coil material is rewound and cut appropriately to produce a JIS 13B plate test piece (JIS Z 2201 (1998))), based on the metal material tensile test method of JIS Z 2241 (1998). Then, perform a tensile test (mark distance GL = 50mm, tensile speed: 5mm / min) along the casting direction at room temperature (about 20 ° C to 25 ° C), and measure tensile strength (MPa) and elongation (%) did. The results are shown in Table 1 (minimum value of n = 5).

表1に示すように、Caを特定の範囲で含有する鋳造材を製造するに当たり、鋳造時の冷却速度を十分に大きくすることで、DASが小さい鋳造材が得られることが分かる。また、得られた鋳造材は、AlとCaとを含む金属間化合物が微細で、そのサイズのばらつきも小さいことが分かる。更に、得られた鋳造材の厚さ方向に亘ってAlとCaとを含む金属間化合物のサイズのばらつきが小さいこと、AlとCaとを含む金属間化合物とDASとの差や和が小さいこと、AlとCaとを含む金属間化合物だけでなくその他の金属間化合物(AlとMgとを含む金属間化合物など)も微細でばらつきが小さいこと、が分かる。従って、得られた鋳造材は、微細な鋳造組織中に微細で均一的な大きさの金属間化合物が分散した組織を有することが分かる。なお、得られた鋳造材を調べたところ、AlとMnとを含む金属間化合物も存在しており、いずれも微細な粒子であった。上述と同様にしてAlとMnとを含む金属間化合物の最大径を調べたところ、0.3μm程度であり、当該金属間化合物の平均粒径は、0.3μm以下であることを確認した。   As shown in Table 1, it can be seen that, in producing a cast material containing Ca in a specific range, a cast material having a small DAS can be obtained by sufficiently increasing the cooling rate during casting. Further, it can be seen that the obtained cast material has a fine intermetallic compound containing Al and Ca, and its size variation is small. Furthermore, the variation in the size of the intermetallic compound containing Al and Ca over the thickness direction of the obtained cast material is small, and the difference or sum between the intermetallic compound containing Al and Ca and DAS is small. It can be seen that not only intermetallic compounds containing Al and Ca but also other intermetallic compounds (such as intermetallic compounds containing Al and Mg) are fine and have little variation. Therefore, it can be seen that the obtained cast material has a structure in which fine and uniform intermetallic compounds are dispersed in a fine cast structure. In addition, when the obtained cast material was investigated, the intermetallic compound containing Al and Mn also existed, and all were fine particles. When the maximum diameter of the intermetallic compound containing Al and Mn was examined in the same manner as described above, it was about 0.3 μm, and it was confirmed that the average particle diameter of the intermetallic compound was 0.3 μm or less.

[試験例2]
上記鋳造材の発火温度を調べた。 [Test Example 2]
The ignition temperature of the cast material was examined.

発火試験は、以下のように行った。上述した鋳造コイル材を巻き戻して、適宜な長さに切断して試験片(質量:3g、n＝3)を作製し、小型の溶解炉中にステンレス製のボードを配置し、このボード内に試験片を配置した。溶解炉内の雰囲気温度を段階的に上昇し、各温度を10分ずつ保持して、試験片の状態を確認する。雰囲気温度は、溶解炉内に配置した熱電対により確認し、溶解炉に内蔵するヒータを調整することで、当該温度を変化させた。各温度で確認したとき、燃焼していなかった場合を○、燃焼した場合は「燃焼」と評価した。その結果を表2に示す。   The ignition test was performed as follows. The above-described cast coil material was rewound and cut to an appropriate length to prepare a test piece (mass: 3 g, n = 3), and a stainless steel board was placed in a small melting furnace. A test piece was placed in Raise the ambient temperature in the melting furnace step by step, hold each temperature for 10 minutes, and check the condition of the test piece. The ambient temperature was confirmed by a thermocouple disposed in the melting furnace, and the temperature was changed by adjusting a heater built in the melting furnace. When confirmed at each temperature, the case where it was not burned was evaluated as “good”, and the case where it was burned was evaluated as “burned”. The results are shown in Table 2.

表2に示すようにCaの含有量が多くなるほど燃焼し難くなり、発火温度が600℃以上、更に650℃以上であることが分かる。また、Caを含有する試料は、Caを含有していない試料と比較して、発火温度を100℃以上、更には150℃以上高められ、難燃性を向上できることが分かる。   As shown in Table 2, as the Ca content increases, it becomes difficult to burn, and it can be seen that the ignition temperature is 600 ° C. or higher, and further 650 ° C. or higher. Further, it can be seen that the sample containing Ca has an ignition temperature increased by 100 ° C. or more, and further 150 ° C. or more, compared with the sample not containing Ca, thereby improving the flame retardancy.

[試験例3]
試験例1で作製した鋳造材に圧延を施して展伸材(圧延材)を作製し、その金属組織を調べた。 [Test Example 3]
The cast material produced in Test Example 1 was rolled to produce a wrought material (rolled material), and the metal structure was examined.

ここでは、各鋳造コイル材に溶体化処理:405℃×17時間(窒素雰囲気、酸素濃度:50質量ppm以下、水冷により冷却)を施して溶体化コイル材を作製した。この溶体化コイル材を巻き戻して温間圧延を施し、厚さ0.62mmの圧延板を作製した。ここでは、上記圧延板を巻き取って圧延コイル材とした。温間圧延は、加工度(圧下率):5％/パス〜40％/パス、素材板の加熱温度:200℃〜350℃、ロール温度:100℃〜250℃とし、複数パス行った。得られた圧延コイル材を巻き戻して温間矯正、研磨処理を順に施し、研磨板(厚さ:0.6mm)を作製した。温間矯正は、上述したロールレベラ装置を用いて行った(温度:300℃)。上記研磨処理は、＃600の研磨ベルトを用いて湿式ベルト式研磨を施した(研磨量:各面0.01mm)。これら温間矯正や研磨処理は省略してもよい。   Here, each cast coil material was subjected to a solution treatment: 405 ° C. × 17 hours (nitrogen atmosphere, oxygen concentration: 50 mass ppm or less, cooled by water cooling) to produce a solution coil material. The solution coil material was rewound and warm-rolled to produce a rolled plate having a thickness of 0.62 mm. Here, the rolled plate was wound up to obtain a rolled coil material. The warm rolling was performed in a plurality of passes at a working degree (rolling rate): 5% / pass to 40% / pass, a heating temperature of the material plate: 200 ° C. to 350 ° C., and a roll temperature: 100 ° C. to 250 ° C. The obtained rolled coil material was rewound and subjected to warm correction and polishing treatment in order to prepare a polishing plate (thickness: 0.6 mm). Warm correction was performed using the roll leveler apparatus described above (temperature: 300 ° C.). In the above polishing treatment, wet belt type polishing was performed using a # 600 polishing belt (polishing amount: 0.01 mm on each surface). These warm correction and polishing treatments may be omitted.

得られた研磨板は、適宜な長さに切断して試験片を作製し、この試験片において圧延方向と直交方向の横断面をSEM-EDXを用いて観察、分析した。SEM観察像(5000倍)を図1(B),図3(B)に示す。図1(B),図3(B)に示すようにいずれの試験片も、組織全体に亘って、微細で、かつ丸みを帯びた金属間化合物が均一的に分散していることが分かる。特に、Caを含有した鋳造材を素材として得られた展伸材:試料No.1-22は、図1(B)に示すように色が異なる金属間化合物、具体的には灰色が濃い粒子と灰色が薄い粒子という、異種の金属間化合物の粒子同士が隣接して粒子群となって分散していることが分かる。この断面をX線回折したところ、粒子群をつくる各金属間化合物のは、Al₂CaといったAlとCaとを含む金属間化合物と、Al₁₂Mg₁₇といったAlとMgとを含む金属間化合物とであることを確認した。このことから、図1(A)に示す鋳造材において網目状に繋がっていた金属間化合物がそのまま繋がった状態で分断されて上記粒子群が形成された、と考えられる。 The obtained polishing plate was cut into an appropriate length to produce a test piece, and the cross section in the direction perpendicular to the rolling direction was observed and analyzed in this test piece using SEM-EDX. SEM observation images (5000 times) are shown in FIGS. 1 (B) and 3 (B). As shown in FIG. 1 (B) and FIG. 3 (B), it can be seen that the fine and round intermetallic compound is uniformly dispersed throughout the entire structure of each test piece. In particular, wrought material obtained using a cast material containing Ca: Sample No. 1-22 is an intermetallic compound with different colors as shown in FIG. It can be seen that particles of different types of intermetallic compounds, such as particles having a light gray color, are adjacently dispersed as a particle group. As a result of X-ray diffraction of this cross section, each intermetallic compound forming the particle group is composed of an intermetallic compound containing Al and Ca such as Al ₂ Ca and an intermetallic compound containing Al and Mg such as Al ₁₂ Mg _17. It was confirmed that. From this, it is considered that the above-mentioned particle group was formed by dividing the intermetallic compound that was connected in a mesh form in the cast material shown in FIG.

各試験片(研磨板)について、AlとCaとを含む金属間化合物の最大径及び平均粒径、AlとMgとを含む金属間化合物の平均粒径、両金属間化合物の最大径の差(絶対値)、表層領域及び中央領域におけるAlとCaとを含む金属間化合物の最大径及び平均粒径、両領域における平均粒径の差を調べた。その結果を表3に示す。AlとCaとを含む金属間化合物と、AlとMgとを含む金属間化合物との抽出は、上記SEM観察像を画像処理して行い、試験例1と同様に観察像中に存在する各金属間化合物の円相当径を求め、この円相当径を粒径とする。そして、3個の観察像中の各金属間化合物の粒径のうち、最も大きい粒径をAlとCaとを含む金属間化合物の最大径、AlとMgとを含む金属間化合物の最大径とした。また、3個の観察像中に存在する各組成の金属間化合物の粒径の平均をAlとCaとを含む金属間化合物の平均粒径、AlとMgとを含む金属間化合物の平均粒径とした。表層領域は、上記各試験片の表面からその厚さ方向に当該試験片の厚さ(0.6mm)の20％までの領域、つまり表面から厚さ方向に0.12mmまでの領域とし、中央領域は、当該試験片の厚さ方向の中心から表面に向かって当該試験片の厚さの±10％までの領域、つまり厚さ方向の中心を含む0.12mmの領域とする。表層領域及び中央領域の最大径及び平均粒径は、上記断面のうち、表層領域、中央領域からそれぞれ上述のようにSEM観察像(5000倍)をとり、画像処理を施して上述のように円相当径を求めて粒径を算出し、各領域における3個の観察像の最大値及び平均値を用いた。また、試験例2と同様に燃焼試験を行い、燃焼した温度を発火温度として、発火温度を調べた。その結果も表3に示す(n＝3のうちの最低温度)。   For each test piece (polishing plate), the maximum diameter and average particle diameter of the intermetallic compound containing Al and Ca, the average particle diameter of the intermetallic compound containing Al and Mg, the difference in the maximum diameter of both intermetallic compounds ( (Absolute value), the maximum diameter and average particle diameter of the intermetallic compound containing Al and Ca in the surface layer region and the central region, and the difference in average particle size in both regions were examined. The results are shown in Table 3. Extraction of an intermetallic compound containing Al and Ca and an intermetallic compound containing Al and Mg is performed by image processing the SEM observation image, and each metal present in the observation image is the same as in Test Example 1. The equivalent circle diameter of the intermetallic compound is determined, and this equivalent circle diameter is defined as the particle diameter. And among the particle sizes of each intermetallic compound in the three observed images, the largest particle size is the maximum diameter of the intermetallic compound containing Al and Ca, the maximum diameter of the intermetallic compound containing Al and Mg, did. In addition, the average particle size of the intermetallic compound of each composition existing in the three observed images is the average particle size of the intermetallic compound containing Al and Ca, the average particle size of the intermetallic compound containing Al and Mg It was. The surface layer area is the area up to 20% of the thickness of the test piece (0.6 mm) in the thickness direction from the surface of each test piece, that is, the area from the surface to 0.12 mm in the thickness direction, and the central area is A region from the center in the thickness direction of the test piece toward the surface up to ± 10% of the thickness of the test piece, that is, a region of 0.12 mm including the center in the thickness direction. The maximum diameter and average particle diameter of the surface layer region and the central region are obtained by taking SEM observation images (5000 times) from the surface layer region and the central region, respectively, in the cross section, and applying image processing to the circle as described above. The equivalent diameter was obtained to calculate the particle diameter, and the maximum value and the average value of the three observation images in each region were used. Further, a combustion test was conducted in the same manner as in Test Example 2, and the ignition temperature was examined using the combustion temperature as the ignition temperature. The results are also shown in Table 3 (the lowest temperature among n = 3).

その他、上記研磨板を適宜切断して、試験例1と同様に板状試験片を作製し、試験例1と同様に、室温(20℃〜25℃程度)で引張試験(標点距離GL=50mm、引張速度:5mm/min)を行い、引張強さ(MPa)及び伸び(％)を測定した(評価数:いずれもn＝5)。その結果を表3に示す(n＝5の最小値)。   In addition, the above polishing plate was appropriately cut to produce a plate-like test piece as in Test Example 1, and as in Test Example 1, a tensile test at room temperature (about 20 ° C. to 25 ° C.) (marking distance GL = The tensile strength (MPa) and the elongation (%) were measured (50 mm, tensile speed: 5 mm / min) (number of evaluations: both n = 5). The results are shown in Table 3 (minimum value of n = 5).

表3に示すように、DASが小さい鋳造材を素材とすることで、Caを特定の範囲で含有したマグネシウム合金であっても、割れなどが生じることなく、展伸加工を良好に施すことができることが分かる。また、得られた展伸材は、引張強さが300MPa以上で発火温度が600℃以上といった、高強度で難燃性に優れることが分かる。従って、試験例1〜3から、Caを特定の範囲で含有したマグネシウム合金から構成され、DASが小さい連続鋳造材は、圧延といった展伸加工性に優れる上に、難燃性にも優れることが分かる。   As shown in Table 3, by using a casting material with a small DAS as a raw material, even if it is a magnesium alloy containing Ca in a specific range, it can be satisfactorily applied without cracking etc. I understand that I can do it. It can also be seen that the obtained wrought material has high strength and excellent flame retardancy, such as a tensile strength of 300 MPa or more and an ignition temperature of 600 ° C. or more. Therefore, from Test Examples 1 to 3, a continuous cast material composed of a magnesium alloy containing Ca in a specific range and having a small DAS is excellent in stretch workability such as rolling, and also excellent in flame retardancy. I understand.

また、得られた展伸材は、AlとCaとを含む金属間化合物やAlとMgとを含む金属間化合物が隣接して存在する他、これら両金属間化合物が微細でばらつきが小さいこと、展伸材の厚さ方向に亘ってAlとCaとを含む金属間化合物のばらつきが小さいこと、上記両金属間化合物の大きさの差も小さいことも分かる。なお、得られた展伸材を調べたところ、AlとMnとを含む金属間化合物も存在しており、鋳造材と同様に最大径が0.3μm程度であった。従って、展伸材についても、当該金属間化合物の平均粒径が0.3μm以下であるといえる。   In addition, the obtained wrought material has an intermetallic compound containing Al and Ca and an intermetallic compound containing Al and Mg adjacent to each other, and these two intermetallic compounds are fine and have little variation. It can also be seen that there is little variation in the intermetallic compound containing Al and Ca across the thickness direction of the wrought material, and that the difference in size between the two intermetallic compounds is also small. When the obtained wrought material was examined, an intermetallic compound containing Al and Mn was also present, and the maximum diameter was about 0.3 μm like the cast material. Therefore, it can be said that the average particle size of the intermetallic compound is 0.3 μm or less for the wrought material.

[試験例4]
試験例3で作製した展伸材(研磨板)に温間プレス加工を施して、マグネシウム合金部材を作製した。 [Test Example 4]
The wrought material (polishing plate) produced in Test Example 3 was warm-pressed to produce a magnesium alloy member.

ここでは、所定の長さに切断した研磨板を用意し、各研磨板を250℃に加熱した状態で円筒深絞り加工(パンチ肩R＝2.0mm)を行い、割れの発生度合いを調べた。具体的には、ブランク径:φ100mm、絞り比2.0、n＝10の試験を行ったところ、いずれの試料も割れなどが生じることなく、深絞り加工を行うことができた。従って、試験例1〜4から、Caを特定の範囲で含有したマグネシウム合金から構成され、DASが小さい連続鋳造材を素材として得られた展伸材は、プレス加工といった塑性加工性に優れることが分かる。   Here, polishing plates cut to a predetermined length were prepared, and cylindrical deep drawing (punch shoulder R = 2.0 mm) was performed in a state where each polishing plate was heated to 250 ° C., and the degree of occurrence of cracks was examined. Specifically, when a blank diameter: φ100 mm, a drawing ratio of 2.0, and n = 10 were tested, all samples could be deep drawn without cracking. Therefore, from Test Examples 1 to 4, a wrought material made of a magnesium alloy containing Ca in a specific range and obtained from a continuously cast material having a small DAS is excellent in plastic workability such as press working. I understand.

[試験例5]
試験例3で作製した展伸材(研磨板)を複数用意して、摩擦撹拌接合により接合して接合材を作製し、この接合材に温間プレス加工を施してマグネシウム合金部材を作製した。 [Test Example 5]
A plurality of wrought materials (polishing plates) prepared in Test Example 3 were prepared, joined by friction stir welding to produce a joining material, and this joining material was subjected to warm press working to produce a magnesium alloy member.

各研磨板の周縁部を切断し、この切断した面の精度が中心線平均粗さRaの標準数列(JIS B 0601(2001年)):6.3μm以下(三角表示による仕上げ記号:▽2つ以上)となるようにエッジを形成し、このエッジを形成した素材(幅:210mm、厚さ:0.6mm)を摩擦撹拌接合により接合した(プローブの先端径:6mm)。得られた接合材に温間プレス加工(素材の加熱温度:250℃)を施し、底面と、底面に立設する側壁とを具える断面]状の筐体(マグネシウム合金部材)を作製した(300mm×300mm×50mm)。   Cut the peripheral edge of each polishing plate, and the accuracy of the cut surface is a standard number sequence with centerline average roughness Ra (JIS B 0601 (2001)): 6.3 μm or less (finished symbol with triangle display: ▽ 2 or more ), And the material (width: 210 mm, thickness: 0.6 mm) on which the edge was formed was joined by friction stir welding (probe tip diameter: 6 mm). The obtained bonding material was subjected to warm press processing (heating temperature of the material: 250 ° C.) to produce a cross-sectional casing (magnesium alloy member) having a bottom surface and side walls standing on the bottom surface ( 300mm x 300mm x 50mm).

その結果、接合領域の一部にも曲げを加えたが、割れなどが生じることなく、また、接合領域で破断することなく、プレス加工を施すことができた。従って、試験例5から、上記展伸材を素材とした接合材も、プレス加工といった塑性加工性に優れることが分かる。   As a result, although a part of the joining region was also bent, it was possible to perform press working without causing cracks and fractures in the joining region. Therefore, it can be seen from Test Example 5 that the bonding material made of the wrought material is also excellent in plastic workability such as press working.

なお、本発明は、上述した実施形態に限定されるものではなく、本発明の要旨を逸脱しない範囲で適宜変更することが可能である。例えば、マグネシウム合金の組成(含有される元素の種類、含有量)、鋳造条件(冷却速度、鋳造ロール間のギャップとノズルの開口部の間隔との関係など)、圧延条件(素材温度、ロール温度など)を適宜変更することができる。   In addition, this invention is not limited to embodiment mentioned above, It can change suitably in the range which does not deviate from the summary of this invention. For example, magnesium alloy composition (type of element contained, content), casting conditions (cooling rate, relationship between gap between casting rolls and gap between nozzle openings, etc.), rolling conditions (material temperature, roll temperature) Etc.) can be changed as appropriate.

本発明マグネシウム合金展伸材や本発明マグネシウム合金接合材は、高強度・高硬度、軽量、耐衝撃性などの特性が望まれる種々の分野の部材、例えば、自動車などの車両、電車、航空機などの飛行機といった輸送機器の構成部材(例えば、ボディー、骨組み、バンパー部品など)、その他、各種の電気・電子機器類の構成部材(筐体など)、カバンや収納ケースなどの各種の収納部材の素材に好適に利用することができる。本発明マグネシウム合金鋳造材や本発明マグネシウム合金鋳造コイル材は、当該鋳造材に圧延、押出、鍛造などの展伸加工が施されてなる上記本発明マグネシウム合金展伸材の素材に好適に利用することができる。本発明マグネシウム合金部材は、上記種々の分野の部材に好適に利用することができる。本発明マグネシウム合金鋳造材の製造方法は、上記マグネシウム合金鋳造材の製造に好適に利用することができる。   The magnesium alloy wrought material and the magnesium alloy bonding material of the present invention are members of various fields where characteristics such as high strength, high hardness, light weight, and impact resistance are desired, for example, vehicles such as automobiles, trains, airplanes, etc. Components of transport equipment such as airplanes (for example, bodies, frames, bumper parts, etc.), other components of various electrical and electronic equipment (cases, etc.), materials for various storage members such as bags and storage cases Can be suitably used. The magnesium alloy cast material of the present invention and the magnesium alloy cast coil material of the present invention are suitably used as the material of the magnesium alloy stretched material of the present invention, which is obtained by subjecting the cast material to a stretching process such as rolling, extrusion, and forging. be able to. The magnesium alloy member of the present invention can be suitably used for members in the various fields described above. The manufacturing method of the magnesium alloy casting material of the present invention can be suitably used for manufacturing the magnesium alloy casting material.

100 鋳造ロール 200 ノズル 210 ノズル本体 220 開口部   100 Casting roll 200 Nozzle 210 Nozzle body 220 Opening

Claims (20)

Alを含有するマグネシウム合金からなるマグネシウム合金鋳造材であって、
前記マグネシウム合金は、
ASTM規格におけるAZ91合金をベース合金とし、更にCaを0.5質量％以上3質量％以下（但し、0.7質量％以上1.8質量％以下を除く）含有し、残部がMg及び不可避不純物であり、
DASが4.5μm未満であり、
AlとCaとを含む第一の金属間化合物と、AlとMgとを含む第二の金属間化合物とを含有し、
前記第一の金属間化合物と前記第二の金属間化合物との両金属間化合物が隣り合って存在する箇所を具え、
前記第一の金属間化合物の平均粒径が2μm以下であるマグネシウム合金鋳造材。 A magnesium alloy casting material made of a magnesium alloy containing Al,
The magnesium alloy is
AZ91 alloy in ASTM standard is used as a base alloy, and Ca is further contained in an amount of 0.5% by mass to 3% by mass (excluding 0.7% by mass to 1.8% by mass), with the balance being Mg and inevitable impurities.
DAS is less than 4.5μm,
Containing a first intermetallic compound containing Al and Ca, and a second intermetallic compound containing Al and Mg,
Comprising a location where both intermetallic compounds of the first intermetallic compound and the second intermetallic compound are present next to each other;
A magnesium alloy casting material in which the average particle size of the first intermetallic compound is 2 µm or less. 前記第一の金属間化合物の最大径が5μm以下である請求項1に記載のマグネシウム合金鋳造材。   2. The magnesium alloy cast material according to claim 1, wherein the maximum diameter of the first intermetallic compound is 5 μm or less. 前記DASと前記第一の金属間化合物の最大径との差の絶対値が2.5μm以下である請求項1又は請求項2に記載のマグネシウム合金鋳造材。   3. The magnesium alloy cast material according to claim 1, wherein an absolute value of a difference between the DAS and the maximum diameter of the first intermetallic compound is 2.5 μm or less. 前記DASと前記第一の金属間化合物の最大径との和が5μm以下である請求項1〜請求項3のいずれか1項に記載のマグネシウム合金鋳造材。   4. The magnesium alloy cast material according to claim 1, wherein the sum of the DAS and the maximum diameter of the first intermetallic compound is 5 μm or less. 前記第二の金属間化合物の平均粒径が2μm以下である請求項1〜請求項4のいずれか1項に記載のマグネシウム合金鋳造材。   5. The magnesium alloy cast material according to claim 1, wherein an average particle diameter of the second intermetallic compound is 2 μm or less. 前記マグネシウム合金鋳造材において、その表面から厚さ方向に当該鋳造材の厚さの20％までの領域を表層領域とし、当該鋳造材の厚さ方向の中心から表面側に向かって当該鋳造材の厚さの10％までの領域を中央領域とするとき、前記表層領域及び前記中央領域の各領域における前記第一の金属間化合物の最大径がいずれも5μm以下、かつ平均粒径がいずれも2μm以下であり、更に、前記表層領域における前記平均粒径と、前記中央領域における前記平均粒径との差が20％以内である請求項1〜請求項5のいずれか1項に記載のマグネシウム合金鋳造材。   In the magnesium alloy cast material, a region up to 20% of the thickness of the cast material in the thickness direction from the surface is defined as a surface layer region, and the cast material When the region up to 10% of the thickness is a central region, the maximum diameter of the first intermetallic compound in each of the surface layer region and the central region is 5 μm or less, and the average particle size is 2 μm. 6. The magnesium alloy according to claim 1, further comprising a difference of 20% or less between the average particle size in the surface region and the average particle size in the central region. Cast material. 前記マグネシウム合金は、AlとMnとを含む第三の金属間化合物を含有し、
前記第三の金属間化合物の平均粒径が2μm以下である請求項1〜請求項6のいずれか1項に記載のマグネシウム合金鋳造材。 The magnesium alloy contains a third intermetallic compound containing Al and Mn,
7. The magnesium alloy cast material according to claim 1, wherein an average particle size of the third intermetallic compound is 2 μm or less. 請求項1〜請求項7のいずれか1項に記載のマグネシウム合金鋳造材であり、長さ100m以上の板状材が巻き取られてなるマグネシウム合金鋳造コイル材。   8. A magnesium alloy cast coil material according to claim 1, which is a magnesium alloy cast material according to any one of claims 1 to 7, wherein a plate material having a length of 100 m or more is wound. Alを含有するマグネシウム合金からなる鋳造材を製造するマグネシウム合金鋳造材の製造方法であって、
ASTM規格におけるAZ91合金をベース合金とし、更にCaを0.5質量％以上3質量％以下（但し、0.7質量％以上1.8質量％以下を除く）含有し、残部がMg及び不可避不純物であるマグネシウム合金の溶湯を準備する準備工程と、
一対の鋳造ロールを具える双ロール連続鋳造機により前記溶湯を連続鋳造して鋳造材を製造する鋳造工程とを具え、
前記準備工程では、所定量のうちの一部のCaを含有するCa含有溶湯を作製してから、残部のCaを添加して前記溶湯を作製し、
前記鋳造工程では、前記鋳造時の冷却速度を1000℃/秒以上5000℃/秒以下とするマグネシウム合金鋳造材の製造方法。 A method for producing a magnesium alloy casting material for producing a casting material comprising a magnesium alloy containing Al,
A molten alloy of magnesium alloy containing AZ91 alloy in the ASTM standard as a base alloy, and further containing Ca 0.5 mass% to 3 mass% (excluding 0.7 mass% to 1.8 mass%) , the balance being Mg and inevitable impurities A preparation process to prepare,
A casting process for producing a cast material by continuously casting the molten metal by a twin roll continuous casting machine comprising a pair of casting rolls,
In the preparation step, after preparing a Ca-containing molten metal containing a part of Ca in a predetermined amount, the remaining Ca is added to prepare the molten metal,
In the casting step, a magnesium alloy cast material manufacturing method in which a cooling rate during casting is 1000 ° C./second or more and 5000 ° C./second or less. 前記一対の鋳造ロール間のギャップをgr、前記鋳造ロールに向かって前記溶湯を排出するノズルの開口部の間隔をgnとするとき、gn＜grとなるように、前記鋳造ロール間のギャップ及び前記ノズルの開口部の間隔の少なくとも一方を調整する請求項9に記載のマグネシウム合金鋳造材の製造方法。   When the gap between the pair of casting rolls is gr, and the gap between the nozzle openings for discharging the molten metal toward the casting roll is gn, the gap between the casting rolls and the 10. The method for producing a magnesium alloy cast material according to claim 9, wherein at least one of the intervals between the nozzle openings is adjusted. Alを含有するマグネシウム合金からなるマグネシウム合金展伸材であって、
前記マグネシウム合金は、
ASTM規格におけるAZ91合金をベース合金とし、更にCaを0.5質量％以上3質量％以下（但し、0.7質量％以上1.8質量％以下を除く）含有し、残部がMg及び不可避不純物であり、
更に、AlとCaとを含む第一の金属間化合物と、AlとMgとを含む第二の金属間化合物とを含有し、
前記第一の金属間化合物と前記第二の金属間化合物との両金属間化合物の粒子が隣り合った粒子群が存在し、
前記第一の金属間化合物の平均粒径が2μm以下であるマグネシウム合金展伸材。
A magnesium alloy wrought material composed of a magnesium alloy containing Al,
The magnesium alloy is
AZ91 alloy in ASTM standard is used as a base alloy, and Ca is further contained in an amount of 0.5% by mass to 3% by mass (excluding 0.7% by mass to 1.8% by mass), with the balance being Mg and inevitable impurities.
Furthermore, containing a first intermetallic compound containing Al and Ca, and a second intermetallic compound containing Al and Mg,
There is a particle group in which particles of both intermetallic compounds of the first intermetallic compound and the second intermetallic compound are adjacent to each other,
A magnesium alloy wrought material, wherein the average particle size of the first intermetallic compound is 2 µm or less.
前記第一の金属間化合物の最大径と前記第二の金属間化合物の最大径との差の絶対値が2μm以下である請求項11に記載のマグネシウム合金展伸材。   12. The expanded magnesium alloy material according to claim 11, wherein an absolute value of a difference between the maximum diameter of the first intermetallic compound and the maximum diameter of the second intermetallic compound is 2 μm or less. 前記第一の金属間化合物の最大径が5μm以下である請求項11又は請求項12に記載のマグネシウム合金展伸材。   13. The expanded magnesium alloy material according to claim 11, wherein the maximum diameter of the first intermetallic compound is 5 μm or less. 前記第二の金属間化合物の平均粒径が2μm以下である請求項11〜請求項13のいずれか1項に記載のマグネシウム合金展伸材。   14. The magnesium alloy wrought material according to claim 11, wherein an average particle diameter of the second intermetallic compound is 2 μm or less. 前記マグネシウム合金展伸材において、その表面から厚さ方向に当該展伸材の厚さの20％までの領域を表層領域とし、当該展伸材の厚さ方向の中心から表面側に向かって当該展伸材の厚さの10％までの領域を中央領域とするとき、前記表層領域及び前記中央領域の各領域における前記第一の金属間化合物の最大径がいずれも5μm以下、かつ平均粒径がいずれも2μm以下であり、更に、前記表層領域における前記平均粒径と、前記中央領域における前記平均粒径との差が20％以内である請求項11〜請求項14のいずれか1項に記載のマグネシウム合金展伸材。   In the magnesium alloy wrought material, a region up to 20% of the thickness of the wrought material in the thickness direction from the surface is defined as a surface layer region, and the region from the center in the thickness direction of the wrought material toward the surface side When a region up to 10% of the thickness of the wrought material is a central region, the maximum diameter of the first intermetallic compound in each of the surface layer region and the central region is 5 μm or less, and the average particle size Either is 2 μm or less, and further, the difference between the average particle size in the surface region and the average particle size in the central region is within 20%. The magnesium alloy wrought material described. 前記マグネシウム合金は、AlとMnとを含む第三の金属間化合物を含有し、
前記第三の金属間化合物の平均粒径が2μm以下である請求項11〜請求項15のいずれか1項に記載のマグネシウム合金展伸材。 The magnesium alloy contains a third intermetallic compound containing Al and Mn,
16. The magnesium alloy wrought material according to claim 11, wherein an average particle size of the third intermetallic compound is 2 μm or less. 前記マグネシウム合金展伸材の発火温度が600℃以上、引張強さが300MPa以上である請求項11〜請求項16のいずれか1項に記載のマグネシウム合金展伸材。   17. The magnesium alloy wrought material according to claim 11, wherein the magnesium alloy wrought material has an ignition temperature of 600 ° C. or higher and a tensile strength of 300 MPa or higher. 請求項1〜請求項7のいずれか1項に記載のマグネシウム合金鋳造材に展伸加工を施すマグネシウム合金展伸材の製造方法。   8. A method for producing a magnesium alloy wrought material, wherein the magnesium alloy cast material according to any one of claims 1 to 7 is drawn. 請求項11〜請求項17のいずれか1項に記載のマグネシウム合金展伸材に、室温以上500℃以下の加熱温度でプレス加工を施してなるマグネシウム合金部材の製造方法。   18. A method for producing a magnesium alloy member obtained by subjecting the magnesium alloy wrought material according to claim 11 to press working at a heating temperature of room temperature to 500 ° C. 請求項11〜請求項17のいずれか1項に記載の複数のマグネシウム合金展伸材と、
前記マグネシウム合金展伸材同士が摩擦撹拌接合により接合された接合領域とを具えるマグネシウム合金接合材。 A plurality of magnesium alloy wrought materials according to any one of claims 11 to 17,
A magnesium alloy bonding material comprising a bonding region in which the magnesium alloy wrought materials are bonded by friction stir welding.