JP4693028B2

JP4693028B2 - Manufacturing method of aluminum alloy material with excellent machinability

Info

Publication number: JP4693028B2
Application number: JP2004263501A
Authority: JP
Inventors: 秀周八太; 寿和田中; 眞一松田; 直樹家田
Original assignee: 株式会社住軽テクノ
Priority date: 2004-09-10
Filing date: 2004-09-10
Publication date: 2011-06-01
Anticipated expiration: 2024-09-10
Also published as: JP2006077298A

Description

本発明は、切削性に優れたアルミニウム合金材、詳しくは、切削加工時に切り屑が細かく分断され、重切削しても割れが生じ難い切削加工性に優れたＡｌ−Ｃｕ−Ｓｎ−Ｂｉ合金材の製造方法に関する。 The present invention relates to an aluminum alloy material excellent in machinability, and more specifically, an Al-Cu-Sn-Bi alloy material excellent in machinability, in which chips are finely divided at the time of cutting and cracking hardly occurs even when heavy cutting is performed. It relates to the manufacturing method .

従来、切削用高強度アルミニウム合金として広く使用されているＡｌ−Ｃｕ系の２０１１合金には、切削性を向上させる目的で、低融点元素のＰｂ、Ｂｉが添加されているが、近年、Ｐｂによる公害問題が採り上げられ、地球環境問題の観点から、有害物質とされるＰｂを含有しない切削用アルミニウム合金の開発が要請され、Ｐｂに代えてＳｎを添加し、ＳｎとＢｉを共存させたＡｌ−Ｃｕ系の切削用アルミニウム合金が提案されている（特許文献１、特許文献２参照）。 Conventionally, low melting point elements Pb and Bi have been added to Al-Cu-based 2011 alloys widely used as high-strength aluminum alloys for cutting in order to improve machinability. From the viewpoint of global environmental problems, the development of an aluminum alloy for cutting that does not contain Pb, which is considered a hazardous substance, is requested. In place of Pb, Sn is added and Al and Sn and Bi coexist. Cu-based aluminum alloys for cutting have been proposed (see Patent Document 1 and Patent Document 2).

これらのアルミニウム合金は、押出加工、引き抜き加工により棒材、管材、線材とし、通常、溶体化処理、焼入れ後、冷間引き抜き加工などの冷間加工を行い、ついで、例えば１５５〜１６５℃で１〜１５時間の時効処理を施したＴ８調質材として使用されており、従来の２０１１合金に相当する強度と、切削性において２０１１合金と同等の切り屑の分断性をそなえている。 These aluminum alloys are made into rods, pipes, and wires by extrusion and drawing, and are usually subjected to cold processing such as cold drawing after solution treatment, quenching, and then, for example, 1 at 155 to 165 ° C. It is used as a T8 tempered material that has been subjected to aging treatment for ˜15 hours, and has a strength equivalent to that of a conventional 2011 alloy and a chip breaking property equivalent to that of the 2011 alloy.

しかしながら、重切削、とくに切削時に被削材の温度が上昇したり、大きな切削応力が負荷される切削条件の場合に、被削材に割れが生じ易いという問題があり、割れの発生を防止するために、切削時のバイトの送り速度を遅くしたり、被削材の冷却を多くしたり、切削条件を調整するなどの対応策を講じている。また、ＳｎとＢｉを共存させたアルミニウム合金の切削性をさらに高めるために、押出加工の押出比を規定し、溶体化処理前に２０％以上の冷間加工を行い、溶体化処理後１０％以上の冷間加工を行い、ついで時効処理を施す手法も提案されている（特許文献３参照）。
アメリカ特許第５，８０３，９９４号明細書アメリカ特許第６，１１３，８５０号明細書特許第２，７２６，４４４号公報 However, there is a problem that cracking is likely to occur in the cutting material under heavy cutting conditions, especially when the cutting material temperature rises during cutting or a large cutting stress is applied, thus preventing the occurrence of cracking. Therefore, measures are taken such as slowing the feed rate of the cutting tool during cutting, increasing the cooling of the work material, and adjusting the cutting conditions. Further, in order to further improve the machinability of the aluminum alloy in which Sn and Bi coexist, the extrusion ratio of the extrusion process is defined, and cold working of 20% or more is performed before the solution treatment, and 10% after the solution treatment. There has also been proposed a technique of performing the above cold working and then performing an aging treatment (see Patent Document 3).
US Patent No. 5,803,994 US Patent No. 6,113,850 Japanese Patent No. 2,726,444

発明者らは、ＳｎとＢｉを共存させたＡｌ−Ｃｕ系合金の成分組成、製造条件を見直し、切削性との関係についてさらに検討を加えた結果としてなされたものであり、その目的は、一層優れた切削性が与えられ、過酷な切削条件を負荷する重切削時においても割れを生じることなく、良好な切削性を得ることを可能とする切削性に優れたアルミニウム合金材の製造方法を提供することにある。 The inventors have been made as a result of reviewing the component composition and manufacturing conditions of an Al—Cu based alloy in which Sn and Bi coexist and further studying the relationship with the machinability, and the purpose is further Provides excellent machinability and provides a method for producing an aluminum alloy material with excellent machinability that can obtain good machinability without causing cracks even during heavy cutting under severe conditions. There is to do.

上記の目的を達成するための請求項１による切削性に優れたアルミニウム合金材の製造方法は、Ｃｕ：３．５〜６．０％、Ｓｎ：０．０５〜１．０％、Ｂｉ：０．０５〜１．５％を含有し、さらにＭｇ：１．０％以下、Ｚｎ：０．６％以下、Ｔｉ：０．３％以下、Ｍｎ：０．３％以下、Ｃｒ：０．３％以下、Ｚｒ：０．３％以下、Ｖ：０．３％以下のうちの１種または２種以上を含有し、残部Ａｌおよび不可避的不純物からなり、該不可避的不純物中のＦｅが０．７０％以下、Ｓｉが０．４０％以下に制限されているＡｌ−Ｃｕ−Ｓｎ−Ｂｉ系合金の押出加工材または引き抜き加工材を、５００〜５４０℃の温度で溶体化処理、水焼入れ後、加工度５〜３０％の冷間引き抜き加工を行い、ついで１７０〜２４０℃で１〜１５時間の時効処理を施すことにより耐力１９０〜３１５ＭＰａのＡｌ−Ｃｕ−Ｓｎ−Ｂｉ系合金材を得ることを特徴とする。 The manufacturing method of the aluminum alloy material excellent in machinability according to claim 1 for achieving the above object is as follows: Cu: 3.5 to 6.0%, Sn: 0.05 to 1.0%, Bi: 0 0.05 to 1.5% , Mg: 1.0% or less, Zn: 0.6% or less, Ti: 0.3% or less, Mn: 0.3% or less, Cr: 0.3% Hereinafter, it contains one or more of Zr: 0.3% or less and V: 0.3% or less, and consists of the balance Al and unavoidable impurities, and Fe in the unavoidable impurities is 0.70. % Or less, Al—Cu—Sn—Bi alloy extruded material or drawn material whose Si is limited to 0.40% or less is processed at a temperature of 500 to 540 ° C. after solution treatment and water quenching. Cold-drawing at 5-30% degree, then aging treatment at 170-240 ° C for 1-15 hours Characterized in that to obtain a Al-Cu-Sn-Bi-based alloy material of the yield strength 190~315MPa by Succoth.

本発明によれば、ＳｎとＢｉを共存させたＡｌ−Ｃｕ系合金材、とくに棒材、管材または線材において、さらに優れた切削性をそなえ、過酷な切削条件を負荷する重切削時においても割れを生じることなく、良好な切削性を得ることを可能とする切削性に優れたアルミニウム合金材の製造方法が提供される。 According to the present invention, Sn—Bi coexisting Al—Cu-based alloy materials, particularly rods, pipes, or wires, have even better cutting properties and cracks even during heavy cutting under severe conditions. Thus, there is provided a method for producing an aluminum alloy material excellent in machinability, which makes it possible to obtain good machinability.

本発明における合金成分の意義および限定理由について説明すると、Ｃｕは、合金マトリックス中に固溶あるいは析出することによって、強度を高め、それによって切削性を向上させるよう機能する。Ｃｕの好ましい含有量は３．５〜６．０％の範囲であり、３．５％未満では過時効処理の効果が小さく、６．０％を超えて含有すると、析出が多くなるため過度の過時効処理が必要となる。 The significance and reasons for limitation of the alloy components in the present invention will be explained. Cu functions as a solid solution or precipitate in the alloy matrix, thereby increasing the strength and thereby improving the machinability. The preferable content of Cu is in the range of 3.5 to 6.0%. If the content is less than 3.5%, the effect of the overaging treatment is small. If the content exceeds 6.0%, the amount of precipitation increases. Overaging treatment is required.

ＳｎおよびＢｉは、ＳｎとＢｉの低融点化合物を形成し、切削性を向上させるよう機能する。ＳｎおよびＢｉの好ましい含有量は、それぞれＳｎ：０．０５〜１．０％、Ｂｉ：０．０５〜１．５％の範囲であり、それぞれ下限値未満では切削時の切り屑の分断性が劣り、上限値を超えると、割れ感受性が高くなって過時効処理の効果が得難くなる。 Sn and Bi function to form a low melting point compound of Sn and Bi and improve machinability. The preferable contents of Sn and Bi are Sn: 0.05 to 1.0% and Bi: 0.05 to 1.5%, respectively. If it is inferior and exceeds the upper limit, the cracking susceptibility becomes high and the effect of the overaging treatment becomes difficult to obtain.

選択成分としてのＴｉは鋳塊組織を微細化するよう作用する。Ｔｉの好ましい含有量は０．３％以下の範囲であり、０．３％を超えると粗大な化合物を生成し易くなり、靱性が低下する。下限値は０．００５％とするが好ましい。 Ti as a selective component acts to refine the ingot structure. The preferable content of Ti is in the range of 0.3% or less, and when it exceeds 0.3%, it becomes easy to produce a coarse compound and the toughness is lowered. The lower limit is preferably 0.005%.

Ｍｎ、Ｃｒ、Ｚｒ、Ｖは、均質化処理時に合金マトリックス中に金属間化合物として析出し、熱間加工時の再結晶粒を微細化し、切削性を向上させるよう機能する。好ましい含有量はそれぞれ０．３％以下の範囲であり、０．３％を超えると粗大な化合物を生成し易くなり、靱性が低下する。 Mn, Cr, Zr, and V precipitate as an intermetallic compound in the alloy matrix during the homogenization process, and function to refine recrystallized grains during hot working and improve machinability. The preferred contents are each in the range of 0.3% or less, and if it exceeds 0.3%, it becomes easy to produce a coarse compound and the toughness is lowered.

Ｚｎ、Ｍｇは、合金マトリックス中に固溶して強度を高め、それによって切削性を向上させるよう機能する。ＺｎおよびＭｇの好ましい含有量は、それぞれＺｎ：０．６％以下、Ｍｇ：１．０％以下の範囲であり、Ｚｎ：０．６％、Ｍｇ：１．０％を超えると、押出性が低下する。 Zn and Mg function in a solid solution in the alloy matrix to increase strength and thereby improve machinability. The preferable contents of Zn and Mg are in the ranges of Zn: 0.6% or less and Mg: 1.0% or less, respectively, and when Zn: 0.6% and Mg: 1.0% are exceeded, the extrudability is descend.

本発明のアルミニウム合金材において、切削性の観点から、不可避的不純物のうち、Ｆｅは０．７０％以下、Ｓｉは０．４０％以下、その他の不可避的不純物はそれぞれ０．０５％以下の範囲に制限することが必要である。 In the aluminum alloy material of the present invention, from the viewpoint of machinability, among the inevitable impurities, Fe is 0.70% or less, Si is 0.40% or less, and other inevitable impurities are 0.05% or less, respectively. It is necessary to limit to

本発明の好ましい形態において、アルミニウム合金材は、押出加工、引き抜き加工により、棒材、管材または線材として供給され、５００〜５４０℃の温度で溶体化処理し、焼入れ（水冷）後、加工度５〜３０％、好ましくは加工度１０〜２０％の冷間引き抜き加工を行い、ついで１７０〜２４０℃の温度で１〜１５時間、好ましくは１〜１０時間の時効処理を施す。 In a preferred embodiment of the present invention, the aluminum alloy material is supplied as a rod, tube or wire by extrusion or drawing, and is subjected to a solution treatment at a temperature of 500 to 540 ° C., and after quenching (water cooling), a processing degree of 5 Cold drawing is performed at -30%, preferably 10-20%, followed by aging at 170-240 ° C. for 1-15 hours, preferably 1-10 hours.

上記の時効処理により、Ａｌ_２Ｃｕ相が微細に析出した後、この相が粗大に成長して、通常の熱処理条件（５１５℃で溶体化処理後、水焼入れし、加工度１５％の冷間引き抜き加工を行い、ついで１６０℃で４時間の時効処理を施す）で得られる最高強度に比べて強度低下が生じ、その耐力は最高強度における耐力の９５〜６０％（１９０〜３１５ＭＰａ程度の耐力）となる。以下、前記１７０〜２４０℃の温度で１〜１５時間の時効処理を過時効処理と言う。 After the Al ₂ Cu phase is finely precipitated by the above-mentioned aging treatment, this phase grows coarsely and is subjected to normal heat treatment conditions (solution treatment at 515 ° C., water quenching, cold working degree 15% The strength is reduced compared to the maximum strength obtained by drawing and then aging treatment at 160 ° C. for 4 hours, and the proof strength is 95 to 60% of the proof strength at the maximum strength (proof strength of about 190 to 315 MPa). It becomes. Hereinafter, the aging treatment for 1 to 15 hours at the temperature of 170 to 240 ° C. is referred to as overaging treatment.

上記の強度低下により重切削時に割れが生じなくなる理由は、従来の熱処理条件で得られる最高強度材は、合金マトリックスの結晶粒内も結晶粒界も共に硬化状態となるから、重切削した場合、結晶粒界に応力が集中して結晶粒界から割れが発生するが、過時効処理により結晶粒内の硬度を低下させることによって、切削時の負荷応力は結晶粒内でも吸収され割れが防止されるものと推定される。耐力を最高強度における耐力の９５〜６０％とすることにより、割れを防止するとともに、十分な強度を与えることができる。 The reason why cracking does not occur at the time of heavy cutting due to the above strength reduction is because the highest strength material obtained under conventional heat treatment conditions is in a cured state in both the crystal grains of the alloy matrix and the crystal grain boundaries, Stress concentrates at the grain boundary and cracks occur from the grain boundary, but by reducing the hardness in the crystal grain by overaging treatment, the load stress at the time of cutting is absorbed even in the crystal grain and cracking is prevented. It is estimated that. By setting the proof stress to 95 to 60% of the maximum proof strength, it is possible to prevent cracking and to provide sufficient strength.

過時効処理の温度が１７０℃未満では過時効となって強度低下が生じるまでに長時間を要するため生産能率の点で好ましくない。過時効処理の温度が２４０℃を超えると、短時間で耐力低下が生じるため強度が安定せず、工業生産上好ましくない。過時効処理の時間が１時間未満では、工業生産において熱処理温度の均一性が劣るため得られる強度が安定せず、１５時間を超えると生産能率が低下し、工業生産上好ましくない。 If the temperature of the overaging treatment is less than 170 ° C., it takes a long time until the strength is lowered due to overaging, which is not preferable in terms of production efficiency. When the temperature of the overaging treatment exceeds 240 ° C., the yield strength is reduced in a short time, so that the strength is not stable, which is not preferable for industrial production. If the overaging time is less than 1 hour, the strength of the heat treatment temperature is inferior in industrial production and the strength obtained is not stable. If it exceeds 15 hours, the production efficiency is lowered, which is not preferable for industrial production.

以下、本発明の実施例を説明する。この実施例は、本発明の一実施態様であり、本発明はこれに限定されるものではない。 Examples of the present invention will be described below. This example is one embodiment of the present invention, and the present invention is not limited to this example.

実施例１、比較例１
連続鋳造により、表１に示す組成を有するアルミニウム合金を押出用ビレット（直径：９０ｍｍ）に造塊し、常法に従って均質化処理を施した後、熱間押出加工を行って、直径２０ｍｍの押出棒を作製した。 Example 1 and Comparative Example 1
By continuous casting, an aluminum alloy having the composition shown in Table 1 is agglomerated into a billet for extrusion (diameter: 90 mm), homogenized according to a conventional method, and then subjected to hot extrusion to produce an extrusion having a diameter of 20 mm. A rod was made.

この押出棒について、５１５℃の温度で溶体化処理、水焼入れ後、直径１８．４ｍｍまで冷間引き抜き加工を行い、ついで表２に示す条件で時効処理（過時効処理を含む）を施し、この時効処理材を試験材として、以下の方法で切削性（切り屑の分断性、切削割れの有無）を評価した。結果を表２に示す。 The extruded bar was subjected to a solution treatment at a temperature of 515 ° C., water quenching, cold drawing to a diameter of 18.4 mm, and then an aging treatment ( including an overaging treatment) under the conditions shown in Table 2. Using the aging treatment material as a test material, the machinability (cutability of chips, presence of cutting cracks) was evaluated by the following method. The results are shown in Table 2.

切削性の評価：長さ５０ｍｍに切断した試験材を、直径１６ｍｍの汎用ドリル（先端角：１２０°）で回転数１２００ｒｐｍ、送り速度１６０ｍｍ／分の条件で、切削油無しで、押出方向と平行な方向に穴あけ加工し、切り屑の分断性を評価し、切削割れの有無を観察した。切り屑の分断性は、切り屑がすべて２０ｍｍ未満のものは良好（○）、２０ｍｍを超える切り屑が生じたものは不良（×）とし、切削割れが認められなかったものは○、切削割れが認められたものは×とした。 Evaluation of machinability: A test material cut to a length of 50 mm was parallel to the extrusion direction without cutting oil under the conditions of a general-purpose drill of 16 mm in diameter (tip angle: 120 °) with a rotation speed of 1200 rpm and a feed rate of 160 mm / min. Drilling was performed in various directions, the chip breaking property was evaluated, and the presence or absence of cutting cracks was observed. The chip breaking property is good (◯) when all the chips are less than 20 mm, bad (×) when chips exceeding 20 mm are produced, and ○ or cutting cracks when no cutting cracks are observed. The case where was recognized as x.

表２にみられるように、本発明に従う試験材Ｎｏ．１〜１１はいずれも、切削試験において、切り屑が微細に分断され、切削割れも認められなかった。これに対して、試験材Ｎｏ．１２は従来の時効処理を施した最高耐力材、試験材Ｎｏ．１３は亜時効材であるため、切り屑が微細に分断されたが、いずれも切削割れが認められた。試験材Ｎｏ．１４は過時効処理の温度が高いため、耐力の低化が大きく切り屑の分断性が劣っている。 As can be seen in Table 2, the test material No. In all of Nos. 1 to 11, chips were finely divided and no cutting cracks were observed in the cutting test. In contrast, test material No. No. 12 is the highest strength material with the conventional aging treatment, test material No. 12. Since 13 is a sub-aged material, the chips were finely divided, but in all cases, cutting cracks were observed. Test material No. No. 14 has a high temperature of the overaging treatment, so that the yield strength is greatly reduced and the chip breaking property is inferior.

Claims

Ｃｕ：３．５〜６．０％（質量％、以下同じ）、Ｓｎ：０．０５〜１．０％、Ｂｉ：０．０５〜１．５％を含有し、さらにＭｇ：１．０％以下、Ｚｎ：０．６％以下、Ｔｉ：０．３％以下、Ｍｎ：０．３％以下、Ｃｒ：０．３％以下、Ｚｒ：０．３％以下、Ｖ：０．３％以下のうちの１種または２種以上を含有し、残部Ａｌおよび不可避的不純物からなり、該不可避的不純物中のＦｅが０．７０％以下、Ｓｉが０．４０％以下に制限されているＡｌ−Ｃｕ−Ｓｎ−Ｂｉ系合金の押出加工材または引き抜き加工材を、５００〜５４０℃の温度で溶体化処理、水焼入れ後、加工度５〜３０％の冷間引き抜き加工を行い、ついで１７０〜２４０℃で１〜１５時間の時効処理を施すことにより耐力１９０〜３１５ＭＰａのＡｌ−Ｃｕ−Ｓｎ−Ｂｉ系合金材を得ることを特徴とする切削性に優れたアルミニウム合金材の製造方法。 Cu: 3.5 to 6.0% (mass%, the same applies hereinafter), Sn: 0.05 to 1.0%, Bi: 0.05 to 1.5% , and Mg: 1.0% Zn: 0.6% or less, Ti: 0.3% or less, Mn: 0.3% or less, Cr: 0.3% or less, Zr: 0.3% or less, V: 0.3% or less Al-Cu containing one or more of them, the balance being Al and inevitable impurities, Fe in the inevitable impurities being limited to 0.70% or less and Si being limited to 0.40% or less -Extruded or drawn material of Sn-Bi alloy is subjected to solution treatment at a temperature of 500 to 540 ° C, water quenching, followed by cold drawing with a working degree of 5 to 30%, and then 170 to 240 ° C. Al-Cu-Sn-Bi composite with a proof stress of 190 to 315 MPa by performing an aging treatment for 1 to 15 hours at Method of manufacturing an aluminum alloy material excellent in machinability, characterized in that to obtain the wood.