JP2016089217A - Tube with internal groove for heat exchanger and manufacturing method therefor - Google Patents
Tube with internal groove for heat exchanger and manufacturing method therefor Download PDFInfo
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
- B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
- B21C37/06—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of tubes or metal hoses; Combined procedures for making tubes, e.g. for making multi-wall tubes
- B21C37/15—Making tubes of special shape; Making tube fittings
- B21C37/20—Making helical or similar guides in or on tubes without removing material, e.g. by drawing same over mandrels, by pushing same through dies ; Making tubes with angled walls, ribbed tubes and tubes with decorated walls
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D53/00—Making other particular articles
- B21D53/02—Making other particular articles heat exchangers or parts thereof, e.g. radiators, condensers fins, headers
- B21D53/06—Making other particular articles heat exchangers or parts thereof, e.g. radiators, condensers fins, headers of metal tubes
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C9/00—Alloys based on copper
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C9/00—Alloys based on copper
- C22C9/05—Alloys based on copper with manganese as the next major constituent
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/08—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of copper or alloys based thereon
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F21/00—Constructions of heat-exchange apparatus characterised by the selection of particular materials
- F28F21/08—Constructions of heat-exchange apparatus characterised by the selection of particular materials of metal
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
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Abstract
Description
本発明は、エアコン、エコキュートなどのクロスフィン型熱交換器の伝熱管用として、加工性に優れる内面溝付管に関する。 The present invention relates to an internally grooved tube excellent in workability as a heat transfer tube of a cross fin type heat exchanger such as an air conditioner or an ecocute.
従来より、ルームエアコン、パッケージエアコンなどの空調機用熱交換器の伝熱管又は冷媒配管には、銅継目無管が多く採用されており、強度や加工性、伝熱性等の諸物性、並びに材料及び加工コストにバランスの取れたりん脱酸銅管（ＪＩＳ Ｈ３３００ Ｃ１２２０Ｔ）が使用されてきた。 Conventionally, many copper seamless pipes have been used for heat transfer pipes or refrigerant pipes of heat exchangers for air conditioners such as room air conditioners and packaged air conditioners. Various physical properties such as strength, workability and heat transfer, and materials In addition, a phosphorus-deoxidized copper pipe (JIS H3300 C1220T) balanced in processing cost has been used.
これらの熱交換器では、主として、内面にらせん状の溝加工を施した銅管（以下、内面溝付管）と、アルミニウム又はアルミニウム合金板からなるフィン（以下、アルミニウムフィン）から構成される。具体的には、熱交換器の伝熱部は、Ｕ字形に曲げ加工（以下、ヘアピン曲げ加工）した銅管をアルミニウムフィンの貫通孔に通し、ヘアピン曲げ加工した銅管内に治具を挿入して拡管することにより、内面溝付管とアルミニウムフィンとを密着させる。そして、更に、このヘアピン曲げ銅管の開放端を拡管して、この拡管開放端部に、同じくＵ字形に曲げ加工したベンド銅管を挿入し、りん銅ろう等のろう材により、ベンド銅管を内面溝付管の拡管開放端部にろう付けすることにより接続して、熱交換器とされる。 These heat exchangers are mainly composed of a copper tube (hereinafter referred to as an internally grooved tube) having an inner surface provided with a spiral groove and a fin made of aluminum or an aluminum alloy plate (hereinafter referred to as an aluminum fin). Specifically, the heat transfer part of the heat exchanger passes a copper pipe bent into a U shape (hereinafter, hairpin bending process) through the through hole of the aluminum fin, and a jig is inserted into the copper pipe subjected to the hairpin bending process. By expanding the tube, the inner grooved tube and the aluminum fin are brought into close contact with each other. Further, the open end of the hairpin bent copper tube is expanded, and a bend copper tube bent into a U shape is inserted into the expanded open end, and the bend copper tube is brazed with a brazing material such as phosphor copper braze. Are connected to the open end of the inner grooved tube by brazing to form a heat exchanger.
近年、伝熱管として用いられる銅管では、伝熱性能の向上やコストダウンの要求により重量の低減、すなわち細径化及び薄肉化が必要となってきており、ヘアピン曲げ加工条件においてもヘアピン曲げピッチが小さく厳しくなる傾向にある。具体的には、外径に対する肉厚の比（ｔ／Ｄ）が０．０４以下まで薄肉化がなされ、ヘアピン曲げピッチが小さく厳しいヘアピン曲げ条件で行われる場合には、ヘアピン曲げの内側部分にしわが発生したり、曲げ部分が偏平したり、外観品質上の価値を著しく損ない、極端な場合、破断が生じるという課題があった。 In recent years, copper pipes used as heat transfer pipes have been required to reduce weight, that is, to have a smaller diameter and thinner wall due to demands for improved heat transfer performance and cost reduction, and hairpin bending pitch even under hairpin bending processing conditions. Tend to be smaller and more severe. Specifically, when the thickness ratio to the outer diameter (t / D) is reduced to 0.04 or less and the hairpin bending pitch is small and the hairpin bending is performed under severe hairpin bending conditions, the inner portion of the hairpin bending is set. There is a problem that wrinkles are generated, bent portions are flattened, the quality in appearance quality is remarkably impaired, and in extreme cases, breakage occurs.
このような曲げ加工性の改善を検討した銅管としては、０．１〜３．０質量%のＳｎ、０．００５〜０．１質量％のＰを含む銅合金において、平均結晶粒径を３０μｍ以下に安定して制御することで加工性に優れることが見出されている（特許文献１）。 As a copper tube for which improvement of such bending workability was studied, an average crystal grain size was determined in a copper alloy containing 0.1 to 3.0% by mass of Sn and 0.005 to 0.1% by mass of P. It has been found that the processability is excellent by stably controlling to 30 μm or less (Patent Document 1).
また、集合組織に着目し、圧延集合組織のβファイバーに属するＣｕ方位、Ｓ方位、Ｂｒａｓｓ方位の各方位の平均面積率の和を１０〜２５％の範囲とすることで、銅管の破壊強度と曲げ加工性を改善できることが提案されている（特許文献２）。 In addition, focusing on the texture, the sum of the average area ratios of the Cu, S, and Brass orientations belonging to the β fiber of the rolled texture is in the range of 10 to 25%, so that the fracture strength of the copper tube It has been proposed that bending workability can be improved (Patent Document 2).
しかし、上記の従来技術は、平滑管においては、大きな効果が期待できるものの、伝熱管として多く用いられる内面溝付管では、平滑管の製造工程である熱間押出、冷間圧延、冷間抽伸に加え、更に中間焼鈍、冷間抽伸、仕上焼鈍が行なわれており、内面溝付銅管において未だ十分な対策ができているとは言えない。 However, although the above-mentioned conventional techniques can be expected to have a great effect in smooth tubes, in the case of internally grooved tubes that are often used as heat transfer tubes, hot extrusion, cold rolling, cold drawing, which are smooth tube manufacturing processes, are used. In addition, intermediate annealing, cold drawing, and finish annealing are performed, and it cannot be said that sufficient countermeasures have been taken for the internally grooved copper pipe.
従って、本発明の目的は、かかる従来の問題点を解決することであり、優れた曲げ加工性を有する熱交換器用内面溝付銅管を提供することにある。 Accordingly, an object of the present invention is to solve such a conventional problem, and to provide an internally grooved copper tube for a heat exchanger having excellent bending workability.
本発明者らは、上記課題を解決すべく鋭意検討を重ねた結果、銅合金の組成を特定の組成とし、その組成を有する銅合金を用いて内面溝付管を製造するときに、中間熱処理から最終熱処理までの間の加工において、外径減少率を６〜１６％として、再結晶集合組織のＧｏｓｓ方位の方位密度を３．２以下に制御することにより、加工性に優れた内面溝付管が得られることを見出し、本発明を完成させるに至った。 As a result of intensive studies to solve the above problems, the present inventors have made the composition of the copper alloy a specific composition, and when producing an internally grooved tube using the copper alloy having the composition, an intermediate heat treatment is performed. In the processing from the initial heat treatment to the final heat treatment, the inner diameter groove with excellent workability is achieved by controlling the orientation density of the Goss orientation of the recrystallized texture to 3.2 or less by setting the outer diameter reduction rate to 6 to 16%. It has been found that a tube can be obtained, and the present invention has been completed.
すなわち、本発明（１）は、銅合金製の熱交換器用内面溝付管であり、
該銅合金は、０．００４〜０．０４０質量％のＰを含有し、残部がＣｕ及び不可避的不純物からなり、
該銅合金の再結晶集合組織のＧｏｓｓ方位の方位密度が、０より大きく且つ３．２以下であること、
を特徴とする熱交換器用内面溝付管を提供するものである。
That is, the present invention (1) is a copper alloy inner grooved tube for a heat exchanger,
The copper alloy contains 0.004 to 0.040% by mass of P, with the balance being Cu and inevitable impurities,
The Goss orientation density of the recrystallized texture of the copper alloy is greater than 0 and less than or equal to 3.2;
An internally grooved tube for a heat exchanger is provided.
また、本発明（２）は、前記銅合金が、更に、Ｆｅ、Ｍｎ、Ｍｇ、Ｃｒ、Ｔｉ及びＺｒからなる群から選択される１種又は２種以上の元素を、合計で０．０７質量％以下含有することを特徴とする（１）記載の熱交換器用内面溝付管を提供するものである。 In the present invention (2), the copper alloy further contains one or more elements selected from the group consisting of Fe, Mn, Mg, Cr, Ti and Zr in a total amount of 0.07 mass. % Or less is provided, and the inner grooved tube for a heat exchanger according to (1) is provided.
また、本発明（３）は、鋳造工程と、熱間押出加工と、冷間加工と、中間熱処理と、転造加工と、最終熱処理と、を順に行う、あるいは、鋳造工程と、冷間加工と、中間熱処理と、転造加工と、最終熱処理と、を順に行う熱交換器用内面溝付管の製造方法であり、
該鋳造工程で、０．００４〜０．０４０質量％のＰを含有し、残部がＣｕ及び不可避的不純物からなる銅合金を鋳造すること、
該中間熱処理から該最終熱処理までの間の加工での外径減少率が６〜１６％であること、
を特徴とする熱交換器用内面溝付管の製造方法を提供するものである。
Moreover, this invention (3) performs a casting process, a hot extrusion process, a cold work, an intermediate heat treatment, a rolling process, and a final heat treatment in order, or a casting process and a cold work. And an intermediate heat treatment, a rolling process, and a final heat treatment in order, a method for producing an internally grooved tube for a heat exchanger,
In the casting step, casting a copper alloy containing 0.004 to 0.040 mass% of P, with the balance being Cu and inevitable impurities,
The outer diameter reduction rate in the processing from the intermediate heat treatment to the final heat treatment is 6 to 16%,
The manufacturing method of the inner surface grooved pipe | tube for heat exchangers characterized by these is provided.
また、本発明（４）は、前記銅合金が、更に、Ｆｅ、Ｍｎ、Ｍｇ、Ｃｒ、Ｔｉ及びＺｒからなる群から選択される１種又は２種以上の元素を、合計で０．０７質量％以下含有することを特徴とする（３）記載の熱交換器用内面溝付管の製造方法を提供するものである。 In the present invention (4), the copper alloy further contains one or more elements selected from the group consisting of Fe, Mn, Mg, Cr, Ti, and Zr in a total amount of 0.07 mass. The method for producing an internally grooved tube for a heat exchanger according to (3) is provided.
本発明によれば、優れた曲げ加工性を有する熱交換器用内面溝付管を提供することができる。 ADVANTAGE OF THE INVENTION According to this invention, the internal grooved pipe | tube for heat exchangers which has the outstanding bending workability can be provided.
本発明の熱交換器用内面溝付管は、銅合金製の熱交換器用内面溝付管であり、
該銅合金は、０．００４〜０．０４０質量％のＰを含有し、残部がＣｕ及び不可避的不純物からなり、
該銅合金の再結晶集合組織のＧｏｓｓ方位の方位密度が、０より大きく且つ３．２以下であること、
を特徴とする熱交換器用内面溝付管である。
The inner grooved tube for heat exchanger of the present invention is an inner grooved tube for heat exchanger made of copper alloy,
The copper alloy contains 0.004 to 0.040% by mass of P, with the balance being Cu and inevitable impurities,
The Goss orientation density of the recrystallized texture of the copper alloy is greater than 0 and less than or equal to 3.2;
An internally grooved tube for a heat exchanger.
先ず、本発明の熱交換器用内面溝付管を形成している銅合金の集合組織及び特性について説明する。 First, the texture and characteristics of the copper alloy forming the inner grooved tube for a heat exchanger of the present invention will be described.
本発明の熱交換器用内面溝付管を形成している銅合金は、その再結晶集合組織において、結晶粒が微細に一様に存在しており、Ｇｏｓｓ方位への方位密度が３．２以下と低い。 In the copper alloy forming the inner grooved tube for heat exchanger of the present invention, the crystal grains are finely and uniformly present in the recrystallized texture, and the orientation density in the Goss orientation is 3.2 or less. And low.
ここで、銅材料の集合組織について説明する。銅等の多結晶材料は、いくつかの特定方位に結晶粒が配向した組織、すなわち集合組織を持つことが多い。上記方位としては、Ｃｕｂｅ方位、Ｇｏｓｓ方位、Ｂｒａｓｓ方位、Ｓ方位、Ｃｏｐｐｅｒ方位等がある。また、結晶方位が均一に分散して集積がないとき、集合組織はランダムであるという。また、集合組織の体積分率が変化すると、塑性異方性が変化することが知られている。 Here, the texture of the copper material will be described. A polycrystalline material such as copper often has a texture in which crystal grains are oriented in some specific orientation, that is, a texture. Examples of the orientation include a Cube orientation, a Goss orientation, a Brass orientation, an S orientation, and a Copper orientation. Also, when the crystal orientation is uniformly dispersed and there is no accumulation, the texture is said to be random. It is also known that the plastic anisotropy changes as the volume fraction of the texture changes.
上記の集合組織は、同一の結晶系であっても加工方法によって異なる。銅管は、一般的に押出によって製造されるが、押出による銅管の集合組織の場合も、圧延による板材の集合組織の場合と同様に、押出素管の押出面と押出方向（押出素管を圧延加工する場合は圧延面と圧延方向）で表される。押出面は面を表すミラー指数（ｈ ｋ ｌ）で表現され、押出方向は方向を表すミラー指数[ｕ ｖ ｗ]で表現される（ｈ、ｋ、ｌ、ｕ、ｖ及びｗは整数）。そして、ｈｕ＋ｋｖ＋ｌｗ＝０の条件を満たすように、ｈ、ｋ及びｌとｕ、ｖ及びｗの順番を入れ替えて得られる２４通りの等価な方位群を取りまとめて、{ｈ，ｋ，ｌ}＜ｕ，ｖ，ｗ＞と表し，方位の一般的表示としている。 The above texture varies depending on the processing method even in the same crystal system. Copper pipes are generally manufactured by extrusion. In the case of a copper tube texture by extrusion, the extrusion surface of the extruded element tube and the direction of extrusion (extrusion element tube) are the same as in the case of a texture of sheet material by rolling. In the case of rolling, the rolling surface and rolling direction). The extrusion surface is represented by a Miller index (h k l) representing a surface, and the extrusion direction is represented by a Miller index [u v w] representing a direction (h, k, l, u, v and w are integers). Then, 24 equivalent azimuth groups obtained by changing the order of h, k, and l and u, v, and w so as to satisfy the condition of hu + kv + lw = 0 are collected, and {h, k, l} <u , V, w>, which is a general indication of the orientation.
かかる表現方法に基づいて、上記各方位は以下のように示される。
Ｃｕｂｅ方位：｛００１｝＜１００＞
Ｇｏｓｓ方位：｛０１１｝＜１００＞
Ｂｒａｓｓ方位：｛０１１｝＜２１１＞
Ｃｏｐｐｅｒ方位：｛１１２｝＜１１１＞
Ｓ方位：｛１２３｝＜６３４＞
Based on such a representation method, each of the above directions is indicated as follows.
Cube orientation: {001} <100>
Goss orientation: {011} <100>
Brass orientation: {011} <211>
Copper orientation: {112} <111>
S orientation: {123} <634>
上記集合組織の方位密度とは、ランダムな方位に対する各方位の強度を比率で示したものである。本発明ではこれらの方位から±１０度以内の方位のずれは同一の方位であると定義する。ただし、Ｃｏｐｐｅｒ方位及びＳ方位に関しては、±９度以内の方位のずれを同一の方位であると定義する。 The orientation density of the texture is the ratio of the strength of each orientation relative to a random orientation. In the present invention, azimuth deviations within ± 10 degrees from these azimuths are defined as the same azimuth. However, regarding the Copper azimuth and the S azimuth, the deviation of the azimuth within ± 9 degrees is defined as the same azimuth.
上記方位密度の分布は、例えば、Ｘ線回折法を用いて、結晶方位分布関数（ＯＤＦ）を求めることにより測定される。具体的には、Ｘ線回折装置で測定した極点図から、３次元方位解析によりＯＤＦを求めることで、各結晶方位の方位密度を求める。ＯＤＦではＢｕｎｇｅの提唱した級数展開法により偶数項の展開次数を２２次、奇数項の展開次数を１９次として計算する。なお、方位密度は、特定方位の方位密度とランダム方位を有する試料の方位密度との比で示し、ランダム比と表記する。ランダム強度Ｉｒについては、検体試料強度Ｉｃから次式により算出する。 The orientation density distribution is measured, for example, by obtaining a crystal orientation distribution function (ODF) using an X-ray diffraction method. Specifically, the orientation density of each crystal orientation is obtained by obtaining ODF by three-dimensional orientation analysis from the pole figure measured by the X-ray diffractometer. In ODF, the expansion order of even terms is calculated as 22nd and the expansion order of odd terms is calculated as 19th by the series expansion method proposed by Bunge. The azimuth density is indicated by a ratio between the azimuth density of a specific azimuth and the azimuth density of a sample having a random azimuth, and is expressed as a random ratio. The random intensity Ir is calculated from the specimen sample intensity Ic by the following formula.
上記数式中、α，βは測定角度，Δsはステップ角度である． In the above formula, α and β are measurement angles, and Δs is a step angle.
本発明の熱交換器用内面溝付管では、曲げ加工性向上の観点から、内面溝付管を形成している銅合金の「ランダムな集合組織」における、Ｇｏｓｓ方位の方位密度の許容量を３．２以下とし、できるだけＧｏｓｓ方位の方位密度を低くする。なお、内面溝付管を形成している銅合金のランダムな集合組織におけるＧｏｓｓ方位を無くす（方位密度を０とする）ことは、製造上困難であるので、本発明の熱交換器用内面溝付管では、内面溝付管を形成している銅合金のＧｏｓｓ方位の方位密度は０より大きくなる。 In the inner grooved tube for heat exchanger of the present invention, from the viewpoint of improving the bending workability, an allowable amount of Goss orientation density in the “random texture” of the copper alloy forming the inner grooved tube is 3 .2 or less, and the orientation density of the Goss orientation as low as possible. In addition, since it is difficult in manufacture to eliminate the Goss orientation in the random texture of the copper alloy forming the inner surface grooved tube (the orientation density is 0), the inner surface grooved for the heat exchanger of the present invention. In the tube, the orientation density of the Goss orientation of the copper alloy forming the inner grooved tube is greater than zero.
そして、本発明の熱交換器用内面溝付管では、内面溝付管のヘアピン曲げ加工性を低下させるＧｏｓｓ方位の方位密度を３．２以下とすれば、ｒ値が１以上となり、ヘアピン曲げ加工における曲げ部内側での座屈、曲げ部での扁平を抑制することができる。つまり、本発明の熱交換器用内面溝付管は、内面溝付管を形成する銅合金のＧｏｓｓ方位の方位密度が０より大きく且つ３．２以下であることにより、ヘアピン曲げ加工における曲げ部内側での座屈、曲げ部での扁平を抑制することができるので、優れた加工性を有する。 In the internally grooved tube for heat exchanger of the present invention, if the Goss orientation density that reduces the hairpin bending workability of the internally grooved tube is 3.2 or less, the r value becomes 1 or more, and the hairpin bending process is performed. It is possible to suppress buckling inside the bent portion and flatness at the bent portion. That is, the inner grooved tube for a heat exchanger of the present invention has a bend inner side in a hairpin bending process because the orientation density of the Goss orientation of the copper alloy forming the inner grooved tube is larger than 0 and 3.2 or less. Since it can suppress buckling and flatness at the bent part, it has excellent workability.
これに対して、内面溝付管を形成している銅合金のＧｏｓｓ方位の方位密度が３．２を超えると、銅管の集合組織におけるＧｏｓｓ方位を有した結晶粒が多過ぎることとなるため、銅管のｒ値が著しく小さくなり、ヘアピン曲げ加工において内面溝付管をバランスよく変形させることができなくなる。この結果、内面溝付管の曲げ部内側での座屈や、曲げ部での扁平化、極端な場合、割れが生じてしまう。 On the other hand, if the Goss orientation density of the copper alloy forming the inner grooved tube exceeds 3.2, there are too many crystal grains having Goss orientation in the texture of the copper tube. The r value of the copper tube is remarkably reduced, and the inner grooved tube cannot be deformed in a balanced manner in the hairpin bending process. As a result, buckling occurs inside the bent portion of the internally grooved tube, flattening at the bent portion, and in extreme cases, cracking occurs.
ランダムな集合組織を構成するＧｏｓｓ方位以外の上記各方位の方位密度は、通常の内面溝付管の製造条件又は製造方法であれば、各々１０以内となり、例えば１０を超えて大きくなることはほとんどない。そして、本発明の熱交換器用内面溝付管では、内面溝付管を形成している銅合金のＧｏｓｓ方位以外の上記各方位の方位密度は、各々１０以内であり、内面溝付管の製造工程上、大きな変化は生じ難く、内面溝付管のヘアピン曲げ加工性には、大きく影響しない。 The orientation density in each of the above-mentioned orientations other than the Goss orientation constituting the random texture is within 10 for each of the normal inner grooved tube manufacturing conditions or manufacturing method, for example, it is almost larger than 10, for example. Absent. And in the internal grooved tube for heat exchangers of this invention, the orientation density of each said direction other than the Goss direction of the copper alloy which forms the internal grooved tube is 10 or less, respectively, and manufacture of an internal grooved tube In the process, a large change hardly occurs and does not greatly affect the hairpin bending workability of the internally grooved tube.
また、本発明の熱交換器用内面溝付管では、内面溝付管を形成している銅合金の平均結晶粒径が３０μｍ以下であることが好ましい。内面溝付管の厚みが比較的厚い場合にはあまり影響ないが、軽量化、薄肉化の要求により、内面溝付管の厚みが特に２００μｍ以下に薄肉化される場合には、この結晶粒径の大きさの影響が著しく大きくなる。すなわち、銅合金の平均結晶粒径が大き過ぎると、内面溝付管の円周方向に加わる引張力によって亀裂が発生する際の「ひずみの集中」を避けることができず、ヘアピン曲げ加工において良好な変形を行うことができない。この結果、上記Ｇｏｓｓ方位の方位密度を制御しても、良好なヘアピン曲げ加工性を維持することが困難となる場合がある。 In the inner grooved tube for heat exchanger of the present invention, it is preferable that the average crystal grain size of the copper alloy forming the inner grooved tube is 30 μm or less. When the thickness of the inner grooved tube is relatively large, there is not much influence, but when the thickness of the inner grooved tube is reduced to 200 μm or less due to the demand for weight reduction and thinning, this crystal grain size The effect of the size of the is significantly increased. In other words, if the average crystal grain size of the copper alloy is too large, it cannot avoid “strain concentration” when cracking occurs due to the tensile force applied in the circumferential direction of the inner grooved tube, which is good for hairpin bending Cannot be transformed. As a result, even if the orientation density of the Goss orientation is controlled, it may be difficult to maintain good hairpin bending workability.
銅合金の平均結晶粒径は、内面溝付管の軸方向に平行の面について、ＪＩＳＨ０５０１に定められた切断法により、内面溝付管の肉厚方向の平均結晶粒径を測定して、これを内面溝付管の軸方向の任意の１０箇所で測定した結果を平均し、平均結晶粒径（μｍ）とする。 The average crystal grain size of the copper alloy is determined by measuring the average crystal grain size in the thickness direction of the inner grooved tube on the surface parallel to the axial direction of the inner grooved tube by the cutting method defined in JISH0501. Are averaged to obtain an average crystal grain size (μm).
次に、本発明の熱交換器用内面溝付管を形成している銅合金の成分組成について説明する。本発明の熱交換器用内面溝付管を形成している銅合金は、０．００４〜０．０４０質量％のＰを含有し、残部がＣｕ及び不可避的不純物からなる。 Next, the component composition of the copper alloy forming the inner grooved tube for a heat exchanger of the present invention will be described. The copper alloy forming the inner grooved tube for a heat exchanger of the present invention contains 0.004 to 0.040% by mass of P, with the balance being Cu and inevitable impurities.
また、本発明の熱交換器用内面溝付管を形成している銅合金は、Ｐに加え、更に、Ｆｅ、Ｍｎ、Ｍｇ、Ｃｒ、Ｔｉ及びＺｒからなる群から選択された１種又は２種以上の元素を合計で０．０７質量％以下含有することができる。つまり、本発明の熱交換器用内面溝付管を形成している銅合金は、０．００４〜０．０４０質量％のＰと、合計で０．０７質量％以下のＦｅ、Ｍｎ、Ｍｇ、Ｃｒ、Ｔｉ及びＺｒからなる群から選択された１種又は２種以上の元素と、を含有し、残部がＣｕ及び不可避的不純物からなる。 In addition to P, the copper alloy forming the inner grooved tube for heat exchanger of the present invention is one or two selected from the group consisting of Fe, Mn, Mg, Cr, Ti and Zr. The total amount of the above elements can be 0.07% by mass or less. That is, the copper alloy forming the inner grooved tube for heat exchanger of the present invention has 0.004 to 0.040 mass% P and a total of 0.07 mass% or less of Fe, Mn, Mg, Cr. And one or more elements selected from the group consisting of Ti and Zr, with the balance being Cu and inevitable impurities.
銅合金中のＰの含有量が０．０４質量％を超えると、応力腐食割れ感受性が高くなると共に、熱伝導率が大きく低下し、また、Ｐの含有量が０．００４質量％未満であると、脱酸不足により酸素量が増加して水素脆化の感受性が高まり、鋳塊の健全性が低下する。よって、本発明の熱交換器用内面溝付管を形成している銅合金のＰ含有量は、０．００４〜０．０４０質量％である。 When the content of P in the copper alloy exceeds 0.04% by mass, the stress corrosion cracking susceptibility becomes high, the thermal conductivity is greatly reduced, and the P content is less than 0.004% by mass. Insufficient deoxidation increases the amount of oxygen, increases the sensitivity to hydrogen embrittlement, and decreases the soundness of the ingot. Therefore, the P content of the copper alloy forming the inner grooved tube for a heat exchanger of the present invention is 0.004 to 0.040% by mass.
Ｆｅ、Ｍｎ、Ｍｇ、Ｃｒ、Ｔｉ及びＺｒはいずれも、銅合金の強度、耐圧破壊強度及び耐熱性を向上させ、結晶粒を微細化して、内面溝付管の曲げ加工性を向上させる。ただし、銅合金がＦｅ、Ｍｎ、Ｍｇ、Ｃｒ、Ｔｉ及びＺｒからなる群から選択される１種又は２種以上の元素を含有する場合、これらの元素の合計含有量が０．０７質量％を超えると、押出圧力が上昇するため、これらの元素を添加しないものと同一の押出力で押出を行おうとすると、熱間押出温度を上げることが必要になり、このことにより、押出材の表面酸化が多くなるので、内面溝付管において表面欠陥が多発してしまう。また、銅合金中のＦｅ、Ｍｎ、Ｍｇ、Ｃｒ、Ｔｉ及びＺｒからなる群から選択される１種又は２種以上の元素の合計含有量が０．０７質量％を超えると、Ｇｏｓｓ方位の方位密度が３．２を超えてしまう。よって、本発明の熱交換器用内面溝付管を形成している銅合金が、Ｆｅ、Ｍｎ、Ｍｇ、Ｃｒ、Ｔｉ及びＺｒからなる群から選択される１種又は２種以上の元素を含有する場合、銅合金中に含有されるこれらの元素の含有量の合計は、０．０７質量％以下、好ましくは０．０１〜０．０７質量％である。 Fe, Mn, Mg, Cr, Ti and Zr all improve the strength, pressure breakdown strength and heat resistance of the copper alloy, refine the crystal grains, and improve the bending workability of the internally grooved tube. However, when the copper alloy contains one or more elements selected from the group consisting of Fe, Mn, Mg, Cr, Ti and Zr, the total content of these elements is 0.07% by mass. Exceeding this will increase the extrusion pressure, so if you want to perform extrusion with the same pushing force as those without adding these elements, it will be necessary to increase the hot extrusion temperature, which will cause surface oxidation of the extruded material. Therefore, surface defects frequently occur in the internally grooved tube. When the total content of one or more elements selected from the group consisting of Fe, Mn, Mg, Cr, Ti and Zr in the copper alloy exceeds 0.07% by mass, the orientation of the Goss orientation Density will exceed 3.2. Therefore, the copper alloy forming the inner grooved tube for a heat exchanger of the present invention contains one or more elements selected from the group consisting of Fe, Mn, Mg, Cr, Ti and Zr. In this case, the total content of these elements contained in the copper alloy is 0.07% by mass or less, preferably 0.01 to 0.07% by mass.
本発明の熱交換器用内面溝付管の外径に対する肉厚の比（ｔ／Ｄ）は、好ましくは０．０２０〜０．０５０、特に好ましくは０．０２５〜０．０５０である。 The thickness ratio (t / D) to the outer diameter of the inner grooved tube for heat exchanger of the present invention is preferably 0.020 to 0.050, and particularly preferably 0.025 to 0.050.
本発明の熱交換器用内面溝付管の製造方法は、鋳造工程と、熱間押出加工と、冷間加工と、中間熱処理と、転造加工と、最終熱処理と、を順に行う、あるいは、鋳造工程と、冷間加工と、中間熱処理と、転造加工と、最終熱処理と、を順に行う熱交換器用内面溝付管の製造方法であり、
該鋳造工程で、０．００４〜０．０４０質量％のＰを含有し、残部がＣｕ及び不可避的不純物からなる銅合金を鋳造すること、
該中間熱処理から該最終熱処理までの間の加工での外径減少率が６〜１６％であること、
を特徴とする熱交換器用内面溝付管の製造方法である。
The method for producing an internally grooved tube for a heat exchanger according to the present invention includes a casting process, a hot extrusion process, a cold process, an intermediate heat treatment, a rolling process, and a final heat treatment in order, or a casting process. It is a manufacturing method of an internally grooved tube for a heat exchanger that performs a process, a cold working, an intermediate heat treatment, a rolling process, and a final heat treatment in order.
In the casting step, casting a copper alloy containing 0.004 to 0.040 mass% of P, with the balance being Cu and inevitable impurities,
The outer diameter reduction rate in the processing from the intermediate heat treatment to the final heat treatment is 6 to 16%,
Is a manufacturing method of an internally grooved tube for a heat exchanger.
また、本発明の熱交換器用内面溝付管の製造方法は、鋳造工程と、熱間押出加工と、冷間加工と、中間熱処理と、転造加工と、最終熱処理と、を順に行う、あるいは、鋳造工程と、冷間加工と、中間熱処理と、転造加工と、最終熱処理と、を順に行う熱交換器用内面溝付管の製造方法であり、
該鋳造工程で、０．００４〜０．０４０質量％のＰと、合計で０．０７質量％のＦｅ、Ｍｎ、Ｍｇ、Ｃｒ、Ｔｉ及びＺｒからなる群から選択される１種又は２種以上の元素と、を含有し、残部がＣｕ及び不可避的不純物からなる銅合金を鋳造すること、
該中間熱処理から該最終熱処理までの間の加工での外径減少率が６〜１６％であること、
を特徴とする熱交換器用内面溝付管の製造方法である。
Further, the method for producing an internally grooved tube for a heat exchanger according to the present invention includes a casting process, a hot extrusion process, a cold process, an intermediate heat treatment, a rolling process, and a final heat treatment in order, or A method for producing an internally grooved tube for a heat exchanger, in which a casting process, cold working, intermediate heat treatment, rolling process, and final heat treatment are sequentially performed,
In the casting step, one or more selected from the group consisting of 0.004 to 0.040 mass% P and a total of 0.07 mass% Fe, Mn, Mg, Cr, Ti and Zr A copper alloy that contains Cu and unavoidable impurities,
The outer diameter reduction rate in the processing from the intermediate heat treatment to the final heat treatment is 6 to 16%,
Is a manufacturing method of an internally grooved tube for a heat exchanger.
本発明の熱交換器用内面溝付管の製造方法では、鋳造工程と、熱間押出加工と、冷間加工と、中間熱処理と、転造加工と、最終熱処理とを順に行うか、あるいは、鋳造工程と、冷間加工と、中間熱処理と、転造加工と、最終熱処理とを順に行う。なお、これら工程を順に行っているのであれば、これらの工程間に必要に応じて、本発明の効果を損なわない範囲で、種々の加工又は熱処理を行うことができる。 In the method for producing an internally grooved tube for a heat exchanger according to the present invention, a casting process, a hot extrusion process, a cold process, an intermediate heat treatment, a rolling process, and a final heat treatment are sequentially performed, or casting A process, a cold working, an intermediate heat treatment, a rolling process, and a final heat treatment are sequentially performed. In addition, if these processes are performed in order, various processes or heat treatments can be performed between these processes as needed within a range not impairing the effects of the present invention.
鋳造工程では、所定の化学成分が所定量含有されている銅合金の鋳塊を鋳造し、所定の寸法のビレットを作製する。例えば、鋳造工程では、原料の電気銅を木炭被覆の状態で溶解し、銅が溶解した後、脱酸を兼ねてＣｕ−１５質量％Ｐ中間合金としてＰを添加する。成分調整が終了した後、半連続鋳造により所定の寸法のビレットを作製する。 In the casting process, a copper alloy ingot containing a predetermined amount of a predetermined chemical component is cast to produce a billet having a predetermined size. For example, in the casting process, the raw electrolytic copper is dissolved in a charcoal-coated state, and after the copper is dissolved, P is added as a Cu-15 mass% P intermediate alloy also serving as deoxidation. After the component adjustment is completed, a billet having a predetermined size is produced by semi-continuous casting.
熱間押出加工では、先ず、熱間押出加工前に上記ビレットを加熱炉にて所定の温度に加熱し、均質化処理を行なう。そして、熱間押出は、マンドレル押出により行われ、すなわち、加工前に冷間で予め穿孔したビレット、あるいは、押出前に熱間で穿孔したビレットに、マンドレルを挿入した状態で、熱間押出を行って、継目無熱間押出素管を得る。 In the hot extrusion process, first, before the hot extrusion process, the billet is heated to a predetermined temperature in a heating furnace and homogenized. The hot extrusion is performed by mandrel extrusion, i.e., hot extrusion is performed with the mandrel inserted into a billet that has been previously perforated cold before processing, or a billet that has been perforated hot before extrusion. To obtain a seamless hot extruded tube.
熱間押出加工を行うことにより得られた継目無熱間押出素管を、熱間押出後、速やかに冷却する。冷却は、継目無熱間押出素管を水中へ押し出すこと又は熱間押出後の継目無熱間押出素管を水中へ投入することによって行われる。 The seamless hot-extrusion element tube obtained by performing the hot extrusion process is rapidly cooled after the hot extrusion. Cooling is performed by extruding the seamless hot-extrusion element tube into water or by introducing the seamless hot-extrusion element tube after hot extrusion into water.
冷間加工では、押出素管に圧延加工及び抽伸加工を行ない、外径と肉厚を低減させる。圧延加工では、加工率を断面減少率で９２％以下とすることにより、圧延時の製品不良を低減できる。抽伸加工は、通常、複数回の加工により行われるが、1回の抽伸における加工率（断面減少率）を３５％以下にすることにより、素管における表面欠陥及び内部割れを低減できる。 In the cold working, rolling and drawing are performed on the extruded raw tube to reduce the outer diameter and the wall thickness. In the rolling process, product defects during rolling can be reduced by setting the processing rate to 92% or less in terms of the cross-sectional reduction rate. Drawing is usually performed by a plurality of times of processing, but surface defects and internal cracks in the raw pipe can be reduced by setting the processing rate (cross-sectional reduction rate) in one drawing to 35% or less.
中間熱処理では、保持温度４００〜７００℃で加熱することにより、転造加工工程での転造加工をし易くする。中間熱処理の昇温速度は、２０℃／分以上、好ましくは４０℃／分以上である。中間熱処理での保持温度が、４００℃未満だと、Ｇｏｓｓ方位の集合組織が発達し過ぎるため、Ｇｏｓｓ方位の方位密度が３．２を超えてしまい、良好なヘアピン曲げ加工性が得られず、また、７００℃を超えると、結晶粒が粗大化されて、転造加工での外観不良の原因となる。 In the intermediate heat treatment, heating at a holding temperature of 400 to 700 ° C. facilitates the rolling process in the rolling process. The temperature increase rate of the intermediate heat treatment is 20 ° C./min or more, preferably 40 ° C./min or more. When the holding temperature in the intermediate heat treatment is less than 400 ° C., the texture structure of the Goss orientation develops too much, the orientation density of the Goss orientation exceeds 3.2, and good hairpin bending workability cannot be obtained. Moreover, when it exceeds 700 degreeC, a crystal grain will coarsen and it will cause the external appearance defect by a rolling process.
転造加工は、管材料の内面に、内面溝を形成させる転造加工を行う工程であり、中間熱処理後の継目無管内に、外面にらせん状の溝加工を施した転造プラグを配置して、高速回転する複数の転造ボールによって、管の外径から押圧して、管の内面に転造プラグの溝を転写することにより行われる。また、通常、中間熱処理を行った後、銅管の径を減ずる縮径加工とあわせて転造加工を行う。 Rolling is a process that forms a groove on the inner surface of the pipe material, and a rolling plug with a spiral groove on the outer surface is placed in the seamless pipe after the intermediate heat treatment. In this way, a plurality of rolling balls rotating at high speed are pressed from the outer diameter of the tube to transfer the groove of the rolling plug to the inner surface of the tube. Moreover, usually, after performing the intermediate heat treatment, the rolling process is performed together with the diameter reducing process for reducing the diameter of the copper pipe.
本発明の熱交換器用内面溝付管の製造方法において、中間熱処理を行った後、最終熱処理を行う前までの間の加工についてであるが、本発明の熱交換器用内面溝付管の製造方法では、中間熱処理を行った後、最終熱処理を行う前までの間に、縮径加工をあわせた転造加工を行う。そして、中間熱処理を行った後から最終熱処理を行う前までの間の加工での外径加工度は、再結晶集合組織の形成に大きく影響を与える。そこで、本発明の熱交換器用内面溝付管の製造方法では、中間熱処理から最終熱処理までの間の加工での外径減少率を１６％以下とすることで、再結晶集合組織におけるＧｏｓｓ方位の方位密度を３．２以下とすることができる。しかし、転造加工での外径減少率を６％未満としようとしても、内面に溝付け加工を行うためのプラグを保持できずに転造加工を行うことができない。よって、本発明の熱交換器用内面溝付管の製造方法では、中間熱処理から最終熱処理までの間の加工での外径減少率を６〜１６％とする。なお、中間熱処理から最終熱処理までの間の加工での外径減少率とは、「（（加工前の外径−加工後の外径）／加工前の外径）×１００」の式で算出され、縮径加工と転造加工とを行う本発明の熱交換器用内面溝付管の製造方法では、縮径及び転造加工前の管の外径に対する縮径及び転造加工後の管の外径の減少率である。 In the method for producing an internally grooved tube for a heat exchanger according to the present invention, the intermediate heat treatment is performed before the final heat treatment, but the method for producing an internally grooved tube for a heat exchanger according to the present invention. Then, after performing the intermediate heat treatment, before the final heat treatment is performed, the rolling process is performed in accordance with the diameter reduction process. The degree of outer diameter processing in the processing after performing the intermediate heat treatment and before performing the final heat treatment greatly affects the formation of the recrystallized texture. Therefore, in the method for manufacturing an internally grooved tube for a heat exchanger according to the present invention, the reduction rate of the outer diameter in the processing from the intermediate heat treatment to the final heat treatment is 16% or less, so that the Goss orientation in the recrystallized texture is reduced. The orientation density can be 3.2 or less. However, even if the outer diameter reduction rate in the rolling process is set to be less than 6%, the rolling process cannot be performed because the plug for grooving cannot be held on the inner surface. Therefore, in the manufacturing method of the internally grooved tube for a heat exchanger of the present invention, the outer diameter reduction rate in the processing from the intermediate heat treatment to the final heat treatment is 6 to 16%. The outer diameter reduction rate in the processing from the intermediate heat treatment to the final heat treatment is calculated by the formula “((outer diameter before processing−outer diameter after processing) / outer diameter before processing) × 100”. In the manufacturing method of the inner grooved tube for a heat exchanger according to the present invention, in which the diameter reduction process and the rolling process are performed, the diameter of the pipe after the diameter reduction and the rolling process is reduced relative to the outer diameter of the pipe before the diameter reduction and the rolling process. This is the decrease rate of the outer diameter.
最終熱処理では、保持温度を４００〜６００℃とすることが好ましい。また、最終熱処理の処理時間は、内面溝付管の引張強さ、０．２％耐力及び伸びが所定の範囲となるように、適宜選択される。 In the final heat treatment, the holding temperature is preferably 400 to 600 ° C. Further, the treatment time for the final heat treatment is appropriately selected so that the tensile strength, 0.2% proof stress and elongation of the internally grooved tube are within a predetermined range.
ここで、最終熱処理での冷却速度が遅いと、冷却過程でＧｏｓｓ方位が発達し易くなり、内面溝付管の集合組織におけるＧｏｓｓ方位の方位密度を３．２以下とすることが難しくなり、また、冷却過程で結晶粒が粗大化し易くなる。このため、最終熱処理の冷却速度は、１．０℃／分以上、好ましくは５．０℃／分以上、特に好ましくは２０．０℃／分以上である。また、結晶粒を粗大化させないためには、最終熱処理での室温から所定温度までの平均昇温速度も速いほうが好ましい。最終熱処理での昇温速度が、５℃／分より遅いと、同じ温度に加熱しても結晶粒が粗大化し易く、耐圧破壊強度及びヘアピン曲げ加工性が低くなり易く、また、生産性を阻害することになる。そのため、最終熱処理での室温から所定温度までの平均昇温速度は５℃／分以上が好ましい。 Here, if the cooling rate in the final heat treatment is slow, the Goss orientation is likely to develop during the cooling process, and it is difficult to reduce the orientation density of the Goss orientation in the texture of the internally grooved tube to 3.2 or less. In the cooling process, the crystal grains are easily coarsened. For this reason, the cooling rate of the final heat treatment is 1.0 ° C./min or more, preferably 5.0 ° C./min or more, and particularly preferably 20.0 ° C./min or more. Moreover, in order not to make the crystal grains coarse, it is preferable that the average temperature increase rate from room temperature to a predetermined temperature in the final heat treatment is also high. If the rate of temperature increase in the final heat treatment is slower than 5 ° C / min, the crystal grains are likely to be coarsened even when heated to the same temperature, the pressure fracture strength and hairpin bending workability are likely to be low, and the productivity is hindered. Will do. Therefore, the average rate of temperature increase from room temperature to a predetermined temperature in the final heat treatment is preferably 5 ° C./min or more.
次に、実施例を挙げて本発明を更に具体的に説明するが、これは単に例示であって、本発明を制限するものではない。 EXAMPLES Next, although an Example is given and this invention is demonstrated more concretely, this is only an illustration and does not restrict | limit this invention.
以下に，内面溝付銅管の実施例を示す。
（１）表１に示す化学成分の鋳塊を溶解及び鋳造し、熱間押出用のビレットを作製した。
（２）上記ビレットを加熱し、８５０℃にて熱間押出を行い、押出素管を得た。次いで、熱間押出した押出素管を、水中に押出して急冷した。
・押出前に熱間で内径約７５ｍｍ穿孔した。
・押出素管の外径は１０２ｍｍ，内径は７５ｍｍであった。
（３）上記押出素管を、ビルガーミル圧延機によって冷間圧延し、圧延素管を得た。
・圧延素管の外径は４６ｍｍ、内径は３９．８ｍｍであった。
・冷間圧延での加工度（断面減少率）は、８８．９％であった。
断面減少率（％）＝（（加工前の断面積−加工後の断面積）／加工前の断面積）×１００
（４）上記の圧延素管を、冷間にて抽伸を複数回行い、抽伸素管を得た。
・抽伸素管の外径は７．８〜１０．０ｍｍ、底肉厚は０．１９〜０．２５ｍｍであった。
・冷間抽伸全体での加工度は、断面減少率で９７．１〜９８．３％であった。
・冷間圧延及び冷間抽伸の総加工度、すなわち、冷間加工の総加工度は、断面減少率で９９．８〜９９．９％であった。
（５）上記の抽伸素管を中間熱処理し、転造加工に供するための原管を得た。
・中間熱処理は保持温度５３０℃で実施した。
（６）上記の原管を、ボール転造加工して、内面溝付管を得た。
＜内面溝付管の寸法諸元＞
・外径：７．０ｍｍ
・肉厚（図２中、符号ｔ）：０．１７ｍｍ
・フィン高さ（図２中、符号ｈ）：０．１６ｍｍ
・フィン頂角（図２中、符号γ）：１０°
・溝条数：４５条
・リード角α（図３中、符号α）：３０°
・転造加工での加工度は、次式により算出した。
断面積減少率（％）＝（（加工前の断面積−加工後の断面積）／加工前の断面積）×１００
外径減少率（％）＝（（加工前の外径−加工後の外径）／加工前の外径）×１００
肉厚減少率（％）＝（（加工前の底肉厚−加工後の底肉厚）／加工前の肉厚）×１００
（７）上記の内面溝付管を、円筒状の整列多層巻きに巻き取り、内面側から巻き解かれる方式のＬＷＣを作製した。その後，下記の条件の最終熱処理を行い、内面溝付管（レベルワウンドコイル（ＬＷＣ））を得た。
・熱処理方法：ローラーハース連続焼鈍炉にて行った。
・条件：保持温度は５００℃で実施した。
An example of an internally grooved copper tube is shown below.
(1) Ingots of chemical components shown in Table 1 were melted and cast to produce billets for hot extrusion.
(2) The billet was heated and subjected to hot extrusion at 850 ° C. to obtain an extruded tube. Next, the extruded extruded tube was extruded into water and quenched.
-The inner diameter was about 75 mm perforated before extrusion.
-The outer diameter of the extruded element tube was 102 mm, and the inner diameter was 75 mm.
(3) The extruded blank was cold-rolled with a Birger mill to obtain a rolled blank.
-The rolling tube had an outer diameter of 46 mm and an inner diameter of 39.8 mm.
-The degree of work in cold rolling (cross-sectional reduction rate) was 88.9%.
Cross-sectional reduction rate (%) = ((cross-sectional area before processing−cross-sectional area after processing) / cross-sectional area before processing) × 100
(4) The above-mentioned rolled blank was cold drawn a plurality of times to obtain a drawn blank.
-The outer diameter of the drawing element tube was 7.8 to 10.0 mm, and the bottom wall thickness was 0.19 to 0.25 mm.
-The workability in the entire cold drawing was 97.1 to 98.3% in terms of the cross-sectional reduction rate.
-The total working degree of cold rolling and cold drawing, that is, the total working degree of cold working was 99.8 to 99.9% in terms of the cross-section reduction rate.
(5) The above drawn element pipe was subjected to intermediate heat treatment to obtain an original pipe for use in rolling.
-The intermediate heat treatment was performed at a holding temperature of 530 ° C.
(6) The above raw pipe was subjected to ball rolling to obtain an internally grooved pipe.
<Dimensions of inner grooved tube>
・ Outer diameter: 7.0mm
-Wall thickness (in FIG. 2, symbol t): 0.17 mm
-Fin height (symbol h in FIG. 2): 0.16 mm
-Fin apex angle (symbol γ in FIG. 2): 10 °
-Number of grooves: 45-Lead angle α (symbol α in Fig. 3): 30 °
-The degree of processing in the rolling process was calculated by the following formula.
Cross-sectional area reduction rate (%) = ((cross-sectional area before processing−cross-sectional area after processing) / cross-sectional area before processing) × 100
Outer diameter reduction rate (%) = ((outer diameter before processing−outer diameter after processing) / outer diameter before processing) × 100
Thickness reduction rate (%) = ((bottom thickness before processing−bottom thickness after processing) / thickness before processing) × 100
(7) The above-inner grooved tube was wound around a cylindrical aligned multilayer winding to produce an LWC of the type that was unwound from the inner surface side. Thereafter, a final heat treatment was performed under the following conditions to obtain an internally grooved tube (level-wound coil (LWC)).
-Heat treatment method: performed in a roller hearth continuous annealing furnace.
-Conditions: The holding temperature was 500 ° C.
製造した内面溝付管に関して、以下の方法で平均結晶粒径、結晶方位分布関数（ＯＤＦ）、引張特性、ヘアピン曲げ加工性を評価した。その結果を表２に記載する。 With respect to the manufactured internally grooved tube, the average crystal grain size, crystal orientation distribution function (ODF), tensile properties, and hairpin bending workability were evaluated by the following methods. The results are listed in Table 2.
＜平均結晶粒径＞
銅管の軸方向に平行の面について、ＪＩＳＨ０５０１に定められた切断法により、銅管の肉厚方向の平均結晶粒径を測定して、これを銅管の軸方向の任意の１０箇所で測定した結果を平均し、平均結晶粒径（μｍ）とした。
<Average crystal grain size>
For the plane parallel to the axial direction of the copper tube, the average crystal grain size in the thickness direction of the copper tube is measured by the cutting method defined in JISH0501, and this is measured at any 10 locations in the axial direction of the copper tube. The results were averaged to obtain an average crystal grain size (μm).
＜結晶方位分布関数（ＯＤＦ）＞
Ｘ線回折装置（株式会社リガク製ＲＩＮＴ２０００）で測定した極点図から、３次元方位解析によりＯＤＦを求めることで、各結晶方位の方位密度を求めた。ＯＤＦについてはＢｕｎｇｅの提唱した級数展開法により偶数項の展開次数を２２次、奇数項の展開次数を１９次として計算した。なお、方位密度は、特定方位の方位密度とランダム方位を有する試料の方位密度との比で示し、ランダム比と表記した。ランダム強度Ｉｒについては検体試料強度Ｉｃから次式により算出した。
<Crystal orientation distribution function (ODF)>
The orientation density of each crystal orientation was obtained by obtaining ODF by three-dimensional orientation analysis from the pole figure measured with an X-ray diffractometer (RINT2000 manufactured by Rigaku Corporation). The ODF was calculated by the series expansion method proposed by Bunge with the expansion order of even terms as 22nd order and the expansion order of odd terms as 19th order. The azimuth density is indicated by a ratio between the azimuth density of a specific azimuth and the azimuth density of a sample having a random azimuth and is expressed as a random ratio. The random intensity Ir was calculated from the specimen sample intensity Ic by the following formula.
＜引張特性＞
引張試験によりｒ値を測定した。試験片は、ＪＩＳ Ｚ２２０１の１１号試験片とし、つかみ部はつち打ちして平片とした。その試験片をインストロン型精密万能試験機にて２０％のひずみを加えて、銅管の外径変化量、肉厚変化量を測定し、ｒ値を算出した。
<Tensile properties>
The r value was measured by a tensile test. The test piece was a JIS Z2201 No. 11 test piece, and the grip portion was punched into a flat piece. The test piece was strained by 20% with an Instron precision universal testing machine, the amount of change in the outer diameter and thickness of the copper tube was measured, and the r value was calculated.
＜ヘアピン曲げ加工性＞
芯金の外径を６．１５ｍｍ、曲げピッチを１６ｍｍとして、ヘアピン加工性の評価を行った。各実施例及び比較例の内面溝付管について，２０本ずつ試験を行った。評価は以下の通りとした。
（Ｉ）しわ発生
ヘアピン曲げの内側部分にしわが発生している内面溝付管の数を数え、下記式にて、しわ発生率を求めた。しわ発生率が０％の場合を合格（○）とした。
しわ発生率（％）＝（しわが発生した管の本数／試験した管の本数）×１００
（ＩＩ）扁平率
ヘアピン曲げ後の曲げ部の扁平率を下記にて算出した。
扁平率（％）＝（（最大外径−最小外径）／呼称外径）×１００
なお，測定位置は、ヘアピン曲げ部の４５°、９０°、１３５°位置であり、呼称外径は、本例では７．０ｍｍである。なお、ヘアピン曲げ部の４５°、９０°、１３５°とは、図１に示すように、内面溝付管を４５°曲げた位置（符号ａ）、９０°曲げた位置（符号ｂ）、１３５°曲げた位置（符号ｃ）である。試験した各内面溝付管の扁平率を求め、扁平率の平均値が１５％以下の場合を合格（○）とした。
<Hairpin bending workability>
The hairpin processability was evaluated by setting the outer diameter of the cored bar to 6.15 mm and the bending pitch to 16 mm. Tests were performed on 20 inner grooved pipes of each example and comparative example. Evaluation was as follows.
(I) Wrinkle generation The number of internally grooved tubes in which wrinkles are generated in the inner part of the hairpin bend was counted, and the wrinkle generation rate was determined by the following formula. The case where the wrinkle occurrence rate was 0% was regarded as acceptable (◯).
Wrinkle generation rate (%) = (number of tubes with wrinkles / number of tubes tested) × 100
(II) Flatness The flatness of the bent part after hairpin bending was calculated as follows.
Flatness (%) = ((maximum outer diameter−minimum outer diameter) / nominal outer diameter) × 100
The measurement positions are 45 °, 90 °, and 135 ° positions of the hairpin bending portion, and the nominal outer diameter is 7.0 mm in this example. In addition, as shown in FIG. 1, 45 °, 90 °, and 135 ° of the hairpin bending portion are a position where the inner grooved tube is bent by 45 ° (symbol a), a position where 90 ° is bent (symbol b), and 135. ° Bent position (reference c). The flatness of each inner grooved tube tested was determined, and the case where the average value of the flatness was 15% or less was determined to be acceptable (◯).
実施例Ｅ１〜Ｅ６では、表１に示すように転造工程での外径減少率を６〜１６％とすることで、表２に示される再結晶集合組織におけるＧｏｓｓ方位の方位密度が３．２以下となり、ｒ値は１以上と高い。また、Ｅ７〜Ｅ１２においても、外径減少率を６〜１６％とすることで、Ｇｏｓｓ方位の方位密度が３．２以下となり、ｒ値は１以上と高い。これらのことにより、実施例Ｅ１〜Ｅ１２では、良好なヘアピン曲げ加工性が得られている。 In Examples E1 to E6, by setting the outer diameter reduction rate in the rolling process to 6 to 16% as shown in Table 1, the orientation density of Goss orientation in the recrystallized texture shown in Table 2 is 3. The r value is as high as 1 or more. Also in E7 to E12, by setting the outer diameter reduction rate to 6 to 16%, the orientation density of the Goss orientation becomes 3.2 or less, and the r value is as high as 1 or more. By these things, in Examples E1-E12, favorable hairpin bending workability is obtained.
比較例Ｃ１、Ｃ２については、転造加工での外径減少率が６％未満であるために内面に溝付け加工を行うためのプラグを保持できずに転造加工を行うことができなかった。 Regarding Comparative Examples C1 and C2, since the outer diameter reduction rate in the rolling process was less than 6%, the rolling process could not be performed without holding the plug for grooving on the inner surface. .
比較例Ｃ３〜Ｃ５では，転造加工を行うことができたものの，外径減少率が１６％を超えたためにＧｏｓｓ方位の方位密度が３．２よりも高くなり、ｒ値が１未満に下がり、必要なヘアピン曲げ加工性が得られなかった。 In Comparative Examples C3 to C5, although the rolling process could be performed, since the outer diameter reduction rate exceeded 16%, the orientation density of the Goss orientation became higher than 3.2, and the r value decreased to less than 1. The necessary hairpin bending workability could not be obtained.
比較例Ｃ６〜Ｃ１２では、成分組成が規定量を越えているために、外径減少率を６〜１６％としても、Ｇｏｓｓ方位の方位密度が高くなり、ヘアピン曲げ加工性が低くなった。 In Comparative Examples C6 to C12, since the component composition exceeded the specified amount, even when the outer diameter reduction rate was 6 to 16%, the orientation density of the Goss orientation was high, and the hairpin bending workability was low.
ｌ 管軸
Ｐ 曲げピッチ
ｔ 肉厚（底肉厚）
ｈ フィン高さ
ｓ 内面溝の最も深い位置
γ フィン頂角
α リード角
l Pipe axis P Bending pitch t Thickness (bottom thickness)
h Fin height s Deepest position of inner groove γ Fin apex angle α Lead angle
Claims (4)
該銅合金は、０．００４〜０．０４０質量％のＰを含有し、残部がＣｕ及び不可避的不純物からなり、
該銅合金の再結晶集合組織のＧｏｓｓ方位の方位密度が、０より大きく且つ３．２以下であること、
を特徴とする熱交換器用内面溝付管。 It is an internally grooved tube for a heat exchanger made of copper alloy,
The copper alloy contains 0.004 to 0.040% by mass of P, with the balance being Cu and inevitable impurities,
The Goss orientation density of the recrystallized texture of the copper alloy is greater than 0 and less than or equal to 3.2;
An internally grooved tube for heat exchangers.
該鋳造工程で、０．００４〜０．０４０質量％のＰを含有し、残部がＣｕ及び不可避的不純物からなる銅合金を鋳造すること、
該中間熱処理から該最終熱処理までの間の加工での外径減少率が６〜１６％であること、
を特徴とする熱交換器用内面溝付管の製造方法。 A casting process, a hot extrusion process, a cold process, an intermediate heat treatment, a rolling process, and a final heat treatment are sequentially performed. Alternatively, a casting process, a cold process, an intermediate heat treatment, and a rolling process are performed. And a final heat treatment in order, a method for producing an internally grooved tube for a heat exchanger,
In the casting step, casting a copper alloy containing 0.004 to 0.040 mass% of P, with the balance being Cu and inevitable impurities,
The outer diameter reduction rate in the processing from the intermediate heat treatment to the final heat treatment is 6 to 16%,
A method for producing an internally grooved tube for a heat exchanger.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
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| JP2014225010A JP6388398B2 (en) | 2014-11-05 | 2014-11-05 | Internal grooved tube for heat exchanger and its manufacturing method |
| MYPI2017701517A MY181594A (en) | 2014-11-05 | 2015-10-29 | Pipe with grooved inner surface for heat exchanger, and process for producing same |
| CN201580060474.8A CN107109531A (en) | 2014-11-05 | 2015-10-29 | Heat exchanger inner face grooved pipe and its manufacture method |
| PCT/JP2015/080495 WO2016072339A1 (en) | 2014-11-05 | 2015-10-29 | Pipe with grooved inner surface for heat exchanger, and process for producing same |
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| JP2014225010A JP6388398B2 (en) | 2014-11-05 | 2014-11-05 | Internal grooved tube for heat exchanger and its manufacturing method |
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| JP (1) | JP6388398B2 (en) |
| CN (1) | CN107109531A (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2018091611A (en) * | 2016-11-30 | 2018-06-14 | 三菱アルミニウム株式会社 | Inner surface spiral grooved pipe, heat exchanger, method of manufacturing inner surface spiral grooved pipe |
| WO2022224940A1 (en) * | 2021-04-19 | 2022-10-27 | 株式会社 Kmct | Corrosion-resistant copper alloy, copper alloy pipe and heat exchanger |
| JP2022165385A (en) * | 2021-04-19 | 2022-10-31 | 株式会社Kmct | Corrosion resistant copper alloy, copper alloy pipe, and heat exchanger |
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| JP2024055690A (en) * | 2022-10-07 | 2024-04-18 | 株式会社Kmct | Corrosion-resistant copper alloys, copper alloy tubes and heat exchangers |
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| JP2009102690A (en) * | 2007-10-23 | 2009-05-14 | Kobelco & Materials Copper Tube Inc | Copper alloy tube for heat exchanger having excellent fracture strength |
| JP2011168846A (en) * | 2010-02-19 | 2011-09-01 | Kobe Steel Ltd | Copper tube for heat exchanger having excellent fracture strength and bending workability |
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| JP6244588B2 (en) * | 2013-03-11 | 2017-12-13 | 株式会社Uacj | Copper alloy seamless pipe for heat transfer tubes |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009102690A (en) * | 2007-10-23 | 2009-05-14 | Kobelco & Materials Copper Tube Inc | Copper alloy tube for heat exchanger having excellent fracture strength |
| JP2011168846A (en) * | 2010-02-19 | 2011-09-01 | Kobe Steel Ltd | Copper tube for heat exchanger having excellent fracture strength and bending workability |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2018091611A (en) * | 2016-11-30 | 2018-06-14 | 三菱アルミニウム株式会社 | Inner surface spiral grooved pipe, heat exchanger, method of manufacturing inner surface spiral grooved pipe |
| WO2022224940A1 (en) * | 2021-04-19 | 2022-10-27 | 株式会社 Kmct | Corrosion-resistant copper alloy, copper alloy pipe and heat exchanger |
| JP2022165385A (en) * | 2021-04-19 | 2022-10-31 | 株式会社Kmct | Corrosion resistant copper alloy, copper alloy pipe, and heat exchanger |
| JP7491960B2 (en) | 2021-04-19 | 2024-05-28 | 株式会社Kmct | Corrosion-resistant copper alloys, copper alloy tubes and heat exchangers |
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| Publication number | Publication date |
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| JP6388398B2 (en) | 2018-09-12 |
| WO2016072339A1 (en) | 2016-05-12 |
| CN107109531A (en) | 2017-08-29 |
| MY181594A (en) | 2020-12-29 |
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