JP2011094176A - Copper alloy seamless tube - Google Patents
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本発明は、空調機用熱交換器、冷凍機等の伝熱管又は冷媒配管に使用される銅合金製の継目無管に関する。 The present invention relates to a copper alloy seamless pipe used for heat transfer pipes or refrigerant pipes of air conditioner heat exchangers, refrigerators and the like.
従来より、ルームエアコン、パッケージエアコン等の空調機用熱交換器、冷凍機等の伝熱管又は冷媒配管には、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 Ｃ１２２０Ｔ）が使用されてきた。 Conventionally, heat pipes for air conditioners such as room air conditioners and packaged air conditioners, and heat transfer pipes or refrigerant pipes for refrigerators, etc., have been adopted with many seamless pipes, and various physical properties such as strength, workability, and heat transfer properties. As well as phosphorus-deoxidized copper tubes (JIS C1220T), which are balanced in material and processing costs have been used.
近年、これらの熱交換器では、重量の低減又はコストダウンの要求により、継目無管の薄肉化が必要となってきており、従来のりん脱酸銅管では強度が低いため、薄肉化は難しく、これに替わる銅合金製の継目無管の開発が求められている。 In recent years, in these heat exchangers, it has become necessary to reduce the thickness of seamless pipes due to demands for weight reduction or cost reduction, and it is difficult to reduce the thickness of conventional phosphorous deoxidized copper pipes because the strength is low. Therefore, there is a demand for the development of a copper alloy seamless pipe that replaces this.
このような銅合金製の継目無管として、国際公開第２００８／０４１７７７号公報（特許文献１）には、加工性に優れ、強度が高く、ロウ付けによる強度低下が少ない、銅合金製の継目無管が開示されている。 As a seamless pipe made of such a copper alloy, International Publication No. 2008/041777 (Patent Document 1) describes a joint made of a copper alloy having excellent workability, high strength, and low strength reduction due to brazing. No pipe is disclosed.
特許文献１によれば、加工性に優れ、強度が高く、ロウ付けによる強度低下が少ない、銅合金製の継目無管が得られるものの、更なる性能向上が求められている。特に、熱交換器等の耐圧強度設計においては、ロウ付け熱影響部の材料強度を元に肉厚を決めるため、ロウ付けによる熱強度低下が少ないことが、熱交換器の作製時の加工性を良好に保ちつつ、伝熱管、冷媒管の薄肉化を可能とするため、更に強度が高く且つロウ付けによる強度低下が少ない銅合金継目無管が要求されている。 According to Patent Document 1, although a copper alloy seamless pipe is obtained that has excellent workability, high strength, and little strength reduction due to brazing, further improvement in performance is required. In particular, in the pressure strength design of heat exchangers, etc., the thickness is determined based on the material strength of the brazed heat-affected zone. In order to make it possible to reduce the thickness of the heat transfer tube and the refrigerant tube while maintaining good, there is a demand for a copper alloy seamless tube having higher strength and less strength reduction due to brazing.
従って、本発明は、強度が高く且つ加工性に優れる銅合金継目無管を提供することにある。更には、本発明は、強度が高く且つロウ付けによる強度低下が少ない銅合金継目無管を提供することにある。 Accordingly, an object of the present invention is to provide a copper alloy seamless pipe having high strength and excellent workability. Furthermore, this invention is providing the copper alloy seamless pipe with high intensity | strength and few intensity | strength fall by brazing.
本発明者らは、上記従来技術における課題を解決すべく、鋭意研究を重ねた結果、銅合金に、特定の元素を特定の含有量で含有させることにより銅合金継目無管の強度を高く且つ加工性に優れる銅合金継目無管が得られること、更に、銅合金の結晶粒度、Ｚｒ系析出物の大きさ及び分布密度を適切にすることにより、強度が高く且つロウ付けによる強度低下が少ない銅合金継目無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-described problems in the prior art, the present inventors have increased the strength of a copper alloy seamless pipe by adding a specific element to a copper alloy with a specific content. A copper alloy seamless pipe excellent in workability can be obtained, and furthermore, by adjusting the crystal grain size of the copper alloy, the size and distribution density of the Zr-based precipitates, the strength is high and the strength reduction due to brazing is small. The inventors have found that a copper alloy seamless pipe can be obtained, and have completed the present invention.
すなわち、本発明（１）は、銅合金を加工して得られる銅合金製の継目無管であり、
該銅合金は、Ｚｎと、０．０１〜０．０８質量％のＺｒと、を含有し、残部Ｃｕ及び不可避不純物からなり、
該銅合金中のＺｎ及びＺｒの含有量が、下記式（１）：
（１）０．４≦Ａ＋２Ｂ≦１．０
（式中、ＡはＺｎの含有量（質量％）を示し、ＢはＺｒの含有量（質量％）を示す。）
を満たすこと、
を特徴とする銅合金継目無管を提供するものである。
That is, the present invention (1) is a copper alloy seamless pipe obtained by processing a copper alloy,
The copper alloy contains Zn and 0.01 to 0.08% by mass of Zr, and consists of the balance Cu and inevitable impurities,
The content of Zn and Zr in the copper alloy is represented by the following formula (1):
(1) 0.4 ≦ A + 2B ≦ 1.0
(In the formula, A represents the Zn content (mass%), and B represents the Zr content (mass%).)
Meeting,
The copper alloy seamless pipe characterized by this is provided.
本発明によれば、強度が高く且つ加工性に優れる銅合金継目無管を提供することができる。更に、本発明によれば、強度が高く且つロウ付けによる強度低下が少ない銅合金継目無管を提供することができる。 According to the present invention, a copper alloy seamless pipe having high strength and excellent workability can be provided. Furthermore, according to the present invention, it is possible to provide a copper alloy seamless pipe having high strength and less strength reduction due to brazing.
本発明の銅合金継目無管は、銅合金を加工して得られる銅合金製の継目無管であり、
該銅合金は、Ｚｎと、０．０１〜０．０８質量％のＺｒと、を含有し、残部Ｃｕ及び不可避不純物からなり、
該銅合金中のＺｎ及びＺｒの含有量が、下記式（１）：
（１）０．４≦Ａ＋２Ｂ≦１．０
（式中、ＡはＺｎの含有量（質量％）を示し、ＢはＺｒの含有量（質量％）を示す。）
を満たす銅合金継目無管である。
The copper alloy seamless pipe of the present invention is a copper alloy seamless pipe obtained by processing a copper alloy,
The copper alloy contains Zn and 0.01 to 0.08% by mass of Zr, and consists of the balance Cu and inevitable impurities,
The content of Zn and Zr in the copper alloy is represented by the following formula (1):
(1) 0.4 ≦ A + 2B ≦ 1.0
(In the formula, A represents the Zn content (mass%), and B represents the Zr content (mass%).)
It is a copper alloy seamless pipe that satisfies
本発明の銅合金継目無管に係る該銅合金は、Ｚｎと、０．０１〜０．０８質量％のＺｒと、を含有し、残部Ｃｕ及び不可避不純物からなる銅合金であり、
該銅合金中のＺｎ及びＺｒの含有量が、下記式（１）：
（１）０．４≦Ａ＋２Ｂ≦１．０
（式中、ＡはＺｎの含有量（質量％）を示し、ＢはＺｒの含有量（質量％）を示す。）
を満たす継目無管用の銅合金である。
そして、本発明の銅合金継目無管に係る該銅合金は、好ましくは、更に下記式（２）：
（２）０．４０≦Ａ
（式中、Ａは、前記と同義である。）
を満たし、且つ、Ｚｒの含有量が０．０６質量％以下である継目無管用の銅合金である。
The copper alloy according to the copper alloy seamless pipe of the present invention is a copper alloy containing Zn and 0.01 to 0.08% by mass of Zr, the balance being Cu and inevitable impurities,
The content of Zn and Zr in the copper alloy is represented by the following formula (1):
(1) 0.4 ≦ A + 2B ≦ 1.0
(In the formula, A represents the Zn content (mass%), and B represents the Zr content (mass%).)
It is a copper alloy for seamless pipes that satisfies
And the copper alloy according to the copper alloy seamless pipe of the present invention is preferably further represented by the following formula (2):
(2) 0.40 ≦ A
(In the formula, A is as defined above.)
And the Zr content is 0.06% by mass or less and is a copper alloy for seamless pipes.
本発明の銅合金継目無管に係る該銅合金は、Ｚｎ及びＺｒを必須元素として含有し、残部Ｃｕ及び不可避不純物からなる銅合金である。 The copper alloy according to the copper alloy seamless pipe of the present invention is a copper alloy containing Zn and Zr as essential elements and comprising the balance Cu and inevitable impurities.
本発明の銅合金継目無管において、Ｚｎには、固溶強化により銅合金の強度を向上させる効果及び常温での延性を向上させる効果がある。また、これらの元素の場合、比較的低温で合金化できるので、製造上有利である。 In the copper alloy seamless pipe of the present invention, Zn has an effect of improving the strength of the copper alloy by solid solution strengthening and an effect of improving ductility at room temperature. In addition, these elements are advantageous in production because they can be alloyed at a relatively low temperature.
本発明の銅合金継目無管において、Ｚｒには、析出強化により銅合金の強度を向上させる効果がある。また、Ｚｒには、ロウ付け温度が過剰に高くならない前提では、Ｚｒ析出物が残存し、結晶粒の粗大化を抑制することにより、強度低下を小さくする効果がある。 In the copper alloy seamless pipe of the present invention, Zr has the effect of improving the strength of the copper alloy by precipitation strengthening. Further, in Zr, on the premise that the brazing temperature does not become excessively high, Zr precipitates remain, and there is an effect of reducing the strength reduction by suppressing the coarsening of crystal grains.
本発明の銅合金継目無管に係る該銅合金中、Ｚｒの含有量は、０．０１〜０．０８質量％である。銅合金中のＺｒの含有量が、０．０１質量％未満だと、結晶粒粗大化を抑制する効果が小さく、ロウ付けによる強度低下が大きくなり、また、Ｚｎによる固溶強化とＺｒによる析出強化を合わせても銅合金の強化が不十分となる。一方、銅合金中のＺｒの含有量が、０．０８質量％を超えると、過剰な析出硬化が起こり、加工性を低下させる原因となる。例えば、厳しい曲げ条件によるヘアピン曲げ加工や、管端の拡管加工の加工性が低下する、などの問題が生じる。 In the copper alloy according to the copper alloy seamless pipe of the present invention, the content of Zr is 0.01 to 0.08 mass%. When the content of Zr in the copper alloy is less than 0.01% by mass, the effect of suppressing the coarsening of the crystal grains is small, the strength is reduced by brazing, and the solid solution strengthening by Zn and the precipitation by Zr. Even if strengthening is combined, the strengthening of the copper alloy becomes insufficient. On the other hand, when the content of Zr in the copper alloy exceeds 0.08% by mass, excessive precipitation hardening occurs, which causes a decrease in workability. For example, problems such as a hairpin bending process under severe bending conditions and a decrease in workability of the pipe end pipe expansion process occur.
本発明の銅合金継目無管に係る該銅合金では、Ａ＋２Ｂは０．４〜１．０であること、すなわち、下記式（１）：
（１）０．４≦Ａ＋２Ｂ≦１．０
を満たす。
銅合金中のＺｒの含有量が０．０８質量％以下であっても、Ｚｎの含有量が多過ぎると、加工硬化が著しくなり、加工性、特に、冷間での引き抜き加工性が悪くなり、中間焼鈍工程を追加する必要が生じ、コスト増大を招くとともに、時効析出によって微細で均一な析出状態を得るための、冷間加工による十分な加工度が確保できなくなる。このため、Ａ＋２Ｂを１．０以下とする必要がある。
また、Ａ＋２Ｂを０．４以上とし、且つ、Ｚｒの含有量を０．０１質量％以上とすることにより、厳しい加工性が必要となる場合でも、銅合金継目無管の強度を最低限維持することができる。一方、Ａ＋２Ｂが０．４未満だと、銅合金継目無管の強度が不足する。
In the copper alloy according to the copper alloy seamless pipe of the present invention, A + 2B is 0.4 to 1.0, that is, the following formula (1):
(1) 0.4 ≦ A + 2B ≦ 1.0
Meet.
Even if the Zr content in the copper alloy is 0.08% by mass or less, if the Zn content is too high, the work hardening becomes remarkable, and the workability, in particular, the cold drawability becomes worse. Further, it becomes necessary to add an intermediate annealing step, resulting in an increase in cost, and it becomes impossible to secure a sufficient workability by cold working for obtaining a fine and uniform precipitation state by aging precipitation. For this reason, A + 2B needs to be 1.0 or less.
Moreover, even when severe workability is required by setting A + 2B to 0.4 or more and the Zr content to 0.01 mass% or more, the strength of the copper alloy seamless pipe is kept to a minimum. be able to. On the other hand, if A + 2B is less than 0.4, the strength of the copper alloy seamless pipe is insufficient.
本発明の銅合金継目無管に係る該銅合金では、好ましくはＡが０．４０以上であること、すなわち、下記式（２）：
（２）０．４０≦Ａ
を満たし、且つ、Ｚｒの含有量が０．０６質量％以下であり、
特に好ましくはＡが０．４３以上であること、すなわち、下記式（２ａ）：
（２ａ）０．４３≦Ａ
を満たし、且つ、Ｚｒの含有量が０．０６質量％以下である。本発明の銅合金継目無管に係る該銅合金のように、Ｚｒ等の析出強化元素を含む銅合金の場合、時効析出によって強度が向上する一方、延性低下を引き起こす。本発明の銅合金継目無管に係る該銅合金では、延性の低下による加工性の阻害を抑えるべく、Ｚｒの含有量の上限を０．０８質量％としてはいるが、厳しい加工性が必要となる場合、例えば、厳しい曲げ条件によるヘアピン曲げ加工や、管端の拡管加工や、高性能化の要求により難加工の内面溝形状を転造加工によって作製する場合などにおいては、十分な加工性を維持するために、Ｚｎを積極的に添加することが望ましい。Ｚｎは、前記のように、常温での延性を向上させる効果があり、Ｚｒの含有量が０．０１〜０．０６質量％の場合、Ｚｒの含有量を０．０６質量％以下とし、且つ、Ｚｎの合計量を０．４０質量％以上とすることにより、加工性改善効果を奏する。
In the copper alloy according to the copper alloy seamless pipe of the present invention, preferably A is 0.40 or more, that is, the following formula (2):
(2) 0.40 ≦ A
And the Zr content is 0.06% by mass or less,
Particularly preferably, A is 0.43 or more, that is, the following formula (2a):
(2a) 0.43 ≦ A
And the Zr content is 0.06% by mass or less. In the case of a copper alloy containing a precipitation strengthening element such as Zr, like the copper alloy according to the copper alloy seamless pipe of the present invention, the strength is improved by aging precipitation, but the ductility is lowered. In the copper alloy according to the copper alloy seamless pipe of the present invention, the upper limit of the Zr content is set to 0.08% by mass in order to suppress the obstruction of workability due to the decrease in ductility, but severe workability is required. In such a case, for example, when a hairpin bending process under severe bending conditions, a pipe end pipe expanding process, or a difficult-to-process inner surface groove shape is produced by a rolling process due to a demand for higher performance, sufficient workability is achieved. In order to maintain, it is desirable to add Zn positively. As described above, Zn has an effect of improving ductility at normal temperature. When the Zr content is 0.01 to 0.06 mass%, the Zr content is 0.06 mass% or less, and When the total amount of Zn is 0.40% by mass or more, the effect of improving workability is exhibited.
本発明の銅合金継目無管に係る該銅合金中のＰの含有量は、０．００４〜０．０４０質量％であることが好ましく、０．０１５〜０．０３０質量％であることが特に好ましい。銅合金が、Ｐ元素を０．００４質量％以上含有することにより、材料中の脱酸が十分であることが示される。そして、銅合金中のＰの含有量が、多すぎると、銅合金の熱伝導性が低くなるので、伝熱管用の場合は特に、銅合金中のＰの含有量は、０．０４０質量％以下が好ましい。 The content of P in the copper alloy according to the copper alloy seamless pipe of the present invention is preferably 0.004 to 0.040 mass%, particularly 0.015 to 0.030 mass%. preferable. It is shown that the deoxidation in the material is sufficient when the copper alloy contains 0.004% by mass or more of the P element. And when there is too much content of P in a copper alloy, since the thermal conductivity of a copper alloy will become low, especially in the case of a heat exchanger tube, content of P in a copper alloy is 0.040 mass%. The following is preferred.
本発明の銅合金継目無管では、該銅合金の平均結晶粒度は３０μｍ以下であり、且つ、大きさが０．５〜８０ｎｍのＺｒ系析出物の分布密度が１０〜６００個／μｍ２であることが好ましい。本発明の銅合金継目無管は、熱交換器等の製造において、ロウ付けに供される継目無管である。このロウ付けの方法としては、炉中ロウ付け、手ロウ付けが挙げられるが、いずれも、ロウ付けに供される継目無管は極部的に、７５０〜９００℃の温度に、最長９００秒間曝されることになる。このロウ付けの間に、微細なＺｒ系析出物の再固溶が起こるため、銅合金の結晶粒は粗大化し、ロウ付けにより継目無管の強度低下が起こる。 In the copper alloy seamless pipe of the present invention, the average grain size of the copper alloy is 30 μm or less, and the distribution density of Zr-based precipitates having a size of 0.5 to 80 nm is 10 to 600 / μm 2 . Preferably there is. The copper alloy seamless pipe of the present invention is a seamless pipe used for brazing in the manufacture of a heat exchanger or the like. Examples of the brazing method include in-furnace brazing and hand brazing. In either case, the seamless pipe used for brazing is locally at a temperature of 750 to 900 ° C. for a maximum of 900 seconds. Will be exposed. During this brazing, fine Zr-based precipitates are re-dissolved, so that the crystal grains of the copper alloy become coarse, and the strength of the seamless pipe is reduced by brazing.
そこで、本発明の銅合金継目無管では、ロウ付け前の平均結晶粒度と、Ｚｒ系析出物の大きさ及び分布密度とを、適切な範囲、すなわち、銅合金の平均結晶粒度は３０μｍ以下とし、且つ、大きさが０．５〜８０ｎｍのＺｒ系析出物の分布密度を１０〜６００個／μｍ２にすることにより、ロウ付けによる銅合金継目無管の強度低下を抑制することができる。微細なＺｒ系析出物が分散していることによって、結晶粒界の移動をピン止め効果で抑制し、結晶粒の粗大化を抑制する効果がある。微細なＺｒ系析出物は、ロウ付け加熱中に部分的に固溶していくために、ピン止め効果は低減し、結晶粒成長を招くものの、本発明の銅合金継目無管では、ロウ付け加熱前のＺｒ系析出物の大きさ及び分布密度を適切な範囲にすることにより、ロウ付け加熱によるピン止め効果の減少を少なくすることができる。そのため、本発明の銅合金継目無管では、銅合金の平均結晶粒度は３０μｍ以下とし、且つ、大きさが０．５〜８０ｎｍのＺｒ系析出物の分布密度を１０〜６００個／μｍ２にすることにより、ロウ付けにより高温で保持された後でも、結晶粒は微細なまま保持されるとともに、強度に寄与するＺｒ系析出物の分散状態も維持される。 Therefore, in the copper alloy seamless pipe of the present invention, the average crystal grain size before brazing and the size and distribution density of the Zr-based precipitates are within an appropriate range, that is, the average crystal grain size of the copper alloy is 30 μm or less. Moreover, by setting the distribution density of the Zr-based precipitates having a size of 0.5 to 80 nm to 10 to 600 / μm 2 , it is possible to suppress the strength reduction of the copper alloy seamless pipe due to brazing. Dispersion of fine Zr-based precipitates has an effect of suppressing movement of crystal grain boundaries by a pinning effect and suppressing coarsening of crystal grains. Since the fine Zr-based precipitates partially dissolve during brazing heating, the pinning effect is reduced, leading to crystal grain growth. However, in the copper alloy seamless pipe of the present invention, brazing is performed. By setting the size and distribution density of the Zr-based precipitates before heating within an appropriate range, the reduction in the pinning effect due to brazing heating can be reduced. Therefore, in the copper alloy seamless pipe of the present invention, the average crystal grain size of the copper alloy is 30 μm or less, and the distribution density of Zr-based precipitates having a size of 0.5 to 80 nm is 10 to 600 / μm 2 . As a result, even after being held at a high temperature by brazing, the crystal grains are kept fine and the dispersed state of the Zr-based precipitates contributing to the strength is also maintained.
本発明の銅合金継目無管に係る該銅合金の平均結晶粒度は、３０μｍ以下であることが好ましい。前述したように、本発明の銅合金継目無管は、ロウ付けに供されるので、時効処理後且つロウ付け前の該銅合金の平均結晶粒度が、３０μｍ以下であることが好ましい。銅合金の平均結晶粒度が上記範囲であることにより、ロウ付け後の結晶粒径が大きくなり過ぎるのを防ぐことができる。 The average grain size of the copper alloy according to the copper alloy seamless pipe of the present invention is preferably 30 μm or less. As described above, since the copper alloy seamless pipe of the present invention is subjected to brazing, the average crystal grain size of the copper alloy after aging treatment and before brazing is preferably 30 μm or less. When the average crystal grain size of the copper alloy is in the above range, the crystal grain size after brazing can be prevented from becoming too large.
本発明の銅合金継目無管に係る該銅合金のＺｒ系析出物は、Ｃｕ３Ｚｒ、ＣｕＺｒ等のＺｒとＣｕとによって構成される析出物又はＺｒとＣｕと他の１種以上の金属元素によって構成される析出物である。 The Zr-based precipitate of the copper alloy according to the copper alloy seamless pipe of the present invention is a precipitate composed of Zr and Cu such as Cu 3 Zr and CuZr, or Zr, Cu and one or more other metal elements It is the deposit comprised by.
本発明の銅合金継目無管において、ロウ付け加熱後もピン止め効果を発揮する該Ｚｒ系析出物の大きさは、０．５〜８０ｎｍである。該Ｚｒ系析出物の大きさが上記範囲未満だと、ロウ付け加熱時に再固溶し消失してしまう、もしくは強度向上に寄与しない大きさまで小さくなってしまう。また、該Ｚｒ系析出物の大きさが上記範囲を超えると、ロウ付け加熱時の結晶粒界のピン止め効果が十分に得られない。 In the copper alloy seamless pipe of the present invention, the size of the Zr-based precipitate that exhibits a pinning effect even after brazing heating is 0.5 to 80 nm. If the size of the Zr-based precipitate is less than the above range, it will be dissolved again and disappear during brazing heating, or it will be reduced to a size that does not contribute to strength improvement. Further, if the size of the Zr-based precipitate exceeds the above range, the crystal grain boundary pinning effect during brazing heating cannot be sufficiently obtained.
本発明の銅合金継目無管に係る該銅合金では、大きさが０．５〜８０ｎｍの該Ｚｒ系析出物の分布密度は、１０〜６００個／μｍ２であることが好ましい。大きさが０．５〜８０ｎｍの該Ｚｒ系析出物の分布密度が上記範囲にあることにより、ロウ付け加熱時に結晶粒の粗大化が起こり難くなり、ロウ付け後の強度低下を少なくでき、加工性も良好となる。特に結晶粒界ピン止め効果に効果的なのは、大きさが０．５〜１０ｎｍの該Ｚｒ系析出物の分布密度が１００〜６００個／μｍ２である。 In the copper alloy according to the copper alloy seamless pipe of the present invention, the distribution density of the Zr-based precipitates having a size of 0.5 to 80 nm is preferably 10 to 600 / μm 2 . When the distribution density of the Zr-based precipitates having a size of 0.5 to 80 nm is in the above range, the coarsening of crystal grains hardly occurs during brazing heating, and the strength reduction after brazing can be reduced. The property is also good. Particularly effective for the grain boundary pinning effect is a distribution density of the Zr-based precipitates having a size of 0.5 to 10 nm of 100 to 600 / μm 2 .
本発明の銅合金継目無管に係る該銅合金では、上記範囲未満の大きさのＺｒ系析出物又は上記範囲を超える大きさのＺｒ系析出物が存在していてもよい。つまり、銅合金中に、上記範囲未満の大きさのＺｒ系析出物又は上記範囲を超える大きさのＺｒ系析出物が存在していても、上記範囲内の大きさのＺｒ系析出物の分布密度が上記範囲内であれば、効果が得られる。 In the copper alloy according to the copper alloy seamless pipe of the present invention, a Zr-based precipitate having a size less than the above range or a Zr-based precipitate having a size exceeding the above range may exist. That is, even if a Zr-based precipitate having a size less than the above range or a Zr-based precipitate having a size exceeding the above range is present in the copper alloy, the distribution of the Zr-based precipitate having a size within the above range is present. An effect is acquired if a density is in the said range.
本発明の銅合金継目無管は、該銅合金の平均結晶粒度が３０μｍ以下であり、且つ、大きさが０．５〜８０ｎｍのＺｒ系析出物の分布密度が１０〜６００個／μｍ２であることにより、Ｚｒ系析出物の大きさ及び分散状態が適切化されているために、ロウ付けによる強度の低下を小さくすることができる。 The copper alloy seamless pipe of the present invention has an average grain size of 30 μm or less and a distribution density of Zr-based precipitates having a size of 0.5 to 80 nm of 10 to 600 / μm 2 . As a result, since the size and dispersion state of the Zr-based precipitates are appropriate, the decrease in strength due to brazing can be reduced.
本発明の銅合金継目無管は、下記式（３）に示す強度低下率が、８００℃で３０秒間の加熱後において、５％以下であることが好ましい。８００℃で３０秒間の加熱後において、強度低下率が５％以下であることが、従来のものに比べ薄肉化を可能とするための指標となる。
強度低下率（％）＝（（ロウ付け前の強度−ロウ付け後の強度）／ロウ付け前の強度）×１００ （３）
（式（３）中、強度は、引張強さ（単位：ＭＰａ）である。）
また、ロウ付け前及びロウ付け後の引張強さは２４５ＭＰａ以上であることが好ましい。
The copper alloy seamless pipe of the present invention preferably has a strength reduction rate of the following formula (3) of 5% or less after heating at 800 ° C. for 30 seconds. An intensity reduction rate of 5% or less after heating at 800 ° C. for 30 seconds is an index for enabling thinning compared to the conventional one.
Strength reduction rate (%) = ((strength before brazing−strength after brazing) / strength before brazing) × 100 (3)
(In formula (3), the strength is the tensile strength (unit: MPa).)
Moreover, it is preferable that the tensile strength before brazing and after brazing is 245 MPa or more.
また、本発明の銅合金継目無管は、Ｚｎ及びＺｒの含有量が適切化されているため、加工性が良好である。 The copper alloy seamless pipe of the present invention has good workability because the contents of Zn and Zr are appropriate.
本発明の銅合金継目無管の形態例としては、内面溝が形成されていない内面平滑管（ベアー管）及び内面溝が形成されている内面溝付管がある。 Examples of forms of the copper alloy seamless pipe of the present invention include an inner surface smooth pipe (bearing pipe) in which no inner groove is formed and an inner grooved pipe in which an inner groove is formed.
該内面平滑管を製造する方法としては、常法に従って、溶解、鋳造し、本発明の銅合金継目無管の所定の元素が所定の含有量で配合されているビレットを得る鋳造工程を行った後、常法に従い、熱間押出工程と、冷間加工工程と、時効処理と、を順に行うことにより製造される。また、該内面溝付管は、常法に従って、溶解、鋳造し、本発明の銅合金継目無管の所定の元素が所定の含有量で配合されているビレットを得る鋳造工程を行った後、常法に従い、熱間押出工程と、冷間加工工程と、転造加工工程と、時効処理と、を順に行うことにより製造される。該鋳造工程については後述する本発明の第一の形態の銅合金継目無管の製造方法及び本発明の第二の形態の銅合金継目無管の製造方法に係る鋳造工程と同様である。なお、該熱間押出工程、該冷間加工工程、該転造加工工程及び該時効処理の条件は、適宜選択される。 As a method for producing the inner smooth tube, a casting process was performed in accordance with a conventional method to obtain a billet in which predetermined elements of the copper alloy seamless pipe of the present invention were blended in a predetermined content by melting and casting. Then, it manufactures by performing a hot extrusion process, a cold working process, and an aging treatment in order according to a conventional method. Further, the inner grooved tube is melted and cast according to a conventional method, and after performing a casting process to obtain a billet in which a predetermined element of the copper alloy seamless pipe of the present invention is blended in a predetermined content, According to a conventional method, it is manufactured by sequentially performing a hot extrusion process, a cold working process, a rolling process process, and an aging treatment. The casting process is the same as the casting process according to the method for manufacturing the copper alloy seamless pipe of the first aspect of the present invention and the method for manufacturing the copper alloy seamless pipe of the second aspect of the present invention. The conditions for the hot extrusion step, the cold working step, the rolling step, and the aging treatment are appropriately selected.
本発明の銅合金継目無管のうち、該銅合金の平均結晶粒度が３０μｍ以下であり、且つ、大きさが０．５〜８０ｎｍのＺｒ系析出物の分布密度が１０〜６００個／μｍ２である銅合金継目無管の製造方法（本発明の第一の形態の銅合金継目無管の製造方法及び本発明の第二の形態の銅合金継目無管の製造方法）について述べる。本発明の第一の形態の銅合金継目無管の製造方法は、銅合金継目無管が内面平滑管である場合の製造方法である。また、本発明の第二の形態の銅合金継目無管の製造方法は、銅合金継目無管が内面溝付管である場合の製造方法である。 Among the copper alloy seamless pipes of the present invention, the average crystal grain size of the copper alloy is 30 μm or less, and the distribution density of Zr-based precipitates having a size of 0.5 to 80 nm is 10 to 600 / μm 2. A method for producing a copper alloy seamless pipe (a method for producing a copper alloy seamless pipe according to the first aspect of the present invention and a method for producing a copper alloy seamless pipe according to the second aspect of the present invention) will be described. The manufacturing method of the copper alloy seamless pipe of the first aspect of the present invention is a manufacturing method in the case where the copper alloy seamless pipe is an inner surface smooth pipe. Moreover, the manufacturing method of the copper alloy seamless pipe of the 2nd form of this invention is a manufacturing method in case a copper alloy seamless pipe is an internal grooved pipe.
本発明の第一の形態の銅合金継目無管の製造方法は、鋳造工程と、熱間押出工程と、冷間加工工程と、時効処理と、を順に行い、
該熱間押出工程と該時効処理との間には中間焼鈍処理を行わず、
該冷間加工工程の総加工度が９０％以上である、
銅合金継目無管の製造方法である。
The method for producing a copper alloy seamless pipe according to the first aspect of the present invention includes a casting process, a hot extrusion process, a cold working process, and an aging treatment in order.
No intermediate annealing treatment is performed between the hot extrusion step and the aging treatment,
The total working degree of the cold working step is 90% or more,
It is a manufacturing method of a copper alloy seamless pipe.
本発明の第一の形態の銅合金継目無管の製造方法では、該鋳造工程と、該熱間押出工程と、該冷間加工工程と、該時効処理と、を順に行う。なお、これらを順に行うとは、該鋳造工程の直後に該熱間押出工程を、該熱間押出工程の直後に該冷間加工工程を、該冷間加工工程の直後に該時効処理を行うということではなく、該鋳造工程より後に該熱間押出工程を、該熱間押出工程より後に該冷間加工工程を、該冷間加工工程より後に該時効処理を行うということ指す。 In the method for producing a copper alloy seamless pipe according to the first aspect of the present invention, the casting step, the hot extrusion step, the cold working step, and the aging treatment are sequentially performed. In order to perform these in order, the hot extrusion process is performed immediately after the casting process, the cold working process is performed immediately after the hot extrusion process, and the aging treatment is performed immediately after the cold working process. Instead, it means that the hot extrusion process is performed after the casting process, the cold working process is performed after the hot extrusion process, and the aging treatment is performed after the cold working process.
また、本発明の第二の形態の銅合金継目無管の製造方法は、鋳造工程と、熱間押出工程と、冷間加工工程と、中間焼鈍処理（Ａ）と、転造加工工程と、時効処理と、を順に行い、
該熱間押出工程と該中間焼鈍処理（Ａ）との間には中間焼鈍処理を行わず、
該冷間加工工程の総加工度が、９０％以上である、
銅合金継目無管の製造方法である。
Moreover, the manufacturing method of the copper alloy seamless pipe of the second aspect of the present invention includes a casting process, a hot extrusion process, a cold working process, an intermediate annealing process (A), a rolling process process, Aging treatment, in order,
No intermediate annealing treatment is performed between the hot extrusion step and the intermediate annealing treatment (A),
The total degree of processing of the cold working step is 90% or more,
It is a manufacturing method of a copper alloy seamless pipe.
本発明の第二の形態の銅合金継目無管の製造方法では、該鋳造工程と、該熱間押出工程と、該冷間加工工程と、該中間焼鈍処理（Ａ）と、該転造加工工程と、該時効処理と、を順に行う。なお、これらを順に行うとは、該鋳造工程の直後に該熱間押出工程を、該熱間押出工程の直後に該冷間加工工程を、該冷間加工工程の直後に該中間焼鈍処理（Ａ）を、該中間焼鈍処理（Ａ）の直後に該転造加工工程を、該転造加工工程の直後に該時効処理を行うということではなく、該鋳造工程より後に該熱間押出工程を、該熱間押出工程より後に該冷間加工工程を、該冷間加工工程より後に該中間焼鈍処理（Ａ）を、該中間焼鈍処理（Ａ）より後に該転造加工工程を、該転造加工工程より後に該時効処理を行うということ指す。 In the method for producing a copper alloy seamless pipe according to the second aspect of the present invention, the casting process, the hot extrusion process, the cold working process, the intermediate annealing process (A), and the rolling process. A process and this aging treatment are performed in order. Note that performing these in order means that the hot extrusion process is performed immediately after the casting process, the cold working process is performed immediately after the hot extrusion process, and the intermediate annealing treatment ( A) does not mean that the rolling process is performed immediately after the intermediate annealing process (A), and the aging process is performed immediately after the rolling process, but the hot extrusion process is performed after the casting process. The cold working step after the hot extrusion step, the intermediate annealing treatment (A) after the cold working step, the rolling step after the intermediate annealing treatment (A), the rolling step. This means that the aging treatment is performed after the processing step.
本発明の第一の形態の銅合金継目無管の製造方法の該鋳造工程から該冷間加工工程までと、本発明の第二の形態の銅合金継目無管の製造方法の該鋳造工程から該冷間加工工程までとは、同様である。 From the casting step to the cold working step of the method for producing a copper alloy seamless pipe according to the first aspect of the present invention, and from the casting step of the method for producing a copper alloy seamless pipe according to the second aspect of the present invention. The process up to the cold working process is the same.
本発明の第一の形態の銅合金継目無管の製造方法及び本発明の第二の形態の銅合金継目無管の製造方法に係る該鋳造工程は、常法に従って、溶解、鋳造し、所定の元素が所定の含有量で配合されているビレットを得る工程である。該鋳造工程では、例えば、銅の地金及び本発明の銅合金継目無管に係る該銅合金の含有元素の地金又は該含有元素と銅の合金を、本発明の銅合金継目無管の銅合金中の含有量が、所定の含有量となるように配合して、成分調整を行い、次いで、高周波溶解炉等を用いて、ビレットを鋳造する。 The casting process according to the method for producing a copper alloy seamless pipe according to the first aspect of the present invention and the method for producing the copper alloy seamless pipe according to the second aspect of the present invention comprises melting, casting, and This is a step of obtaining a billet in which the above elements are blended in a predetermined content. In the casting process, for example, the ingot of the element contained in the copper alloy and the alloy of the copper alloy according to the copper alloy seamless pipe of the present invention or the alloy of the element and copper is used for the copper alloy seamless pipe of the present invention. It mix | blends so that content in a copper alloy may become predetermined content, a component adjustment is performed, and then a billet is cast using a high frequency melting furnace etc. FIG.
Ｚｒは活性な金属なので、溶解時の酸化ロスが多くなるため、成分調整においては、Ｚｒの溶解時の酸化ロスを考慮した配合が必要である。 Since Zr is an active metal, the oxidation loss at the time of dissolution increases. Therefore, in adjusting the components, it is necessary to blend in consideration of the oxidation loss at the time of dissolution of Zr.
また、該鋳造工程では、Ｐを配合することにより、溶湯の流動性が高くなるので、鋳造性が高くなり、ガス孔等の鋳造欠陥の発生が抑制され、また、脱酸効果が得られるので、上記Ｚｒの溶解時の酸化ロスを少なくすることができる。そして、Ｐの配合量が多くなりすぎると、銅合金中のＰ元素の含有量が多くなりすぎるため、熱伝導性が低くなる。そのため、該鋳造工程では、銅合金中のＰ含有量が、０．００４〜０．０４０質量％となるようにＰを配合することが好ましく、０．０１５〜０．０３０質量％となるようにＰを配合することが特に好ましい。 Further, in the casting process, by adding P, the fluidity of the molten metal is increased, so that the castability is improved, the occurrence of casting defects such as gas holes is suppressed, and the deoxidation effect is obtained. The oxidation loss during the dissolution of Zr can be reduced. And when the compounding quantity of P increases too much, since content of P element in a copper alloy will increase too much, thermal conductivity will become low. Therefore, in this casting process, it is preferable to mix | blend P so that P content in a copper alloy may be 0.004-0.040 mass%, and it may become 0.015-0.030 mass%. It is particularly preferable to blend P.
詳細には、該鋳造工程では、最終の工程である該時効処理を行うことにより得られる銅合金継目無管の化学組成が、本発明の銅合金継目無管の化学組成となるように、該鋳造工程を行うことにより得られる該ビレットの化学組成を調節する。該ビレットは、Ｚｎと、０．０１〜０．０８質量％のＺｒと、を含有し、残部Ｃｕ及び不可避不純物からなり、Ｚｎ及びＺｒの含有量が、下記式（１）：
（１）０．４≦Ａ＋２Ｂ≦１．０
（式中、ＡはＺｎの含有量（質量％）を示し、ＢはＺｒの含有量（質量％）を示す。）
を満たす。好ましくは、該ビレット中のＺｎ及びＺｒの含有量が、更に、下記式（２）：
（２）０．４０≦Ａ
（式中、Ａは、前記と同義である。）
を満たし、且つ、Ｚｒの含有量が０．０６質量％以下である。また、該ビレットは、Ｐを含有することもでき、その場合のＰの含有量は０．００４〜０．０４質量％である。
Specifically, in the casting process, the chemical composition of the copper alloy seamless pipe obtained by performing the aging treatment as the final process becomes the chemical composition of the copper alloy seamless pipe of the present invention. The chemical composition of the billet obtained by performing the casting process is adjusted. The billet contains Zn and 0.01 to 0.08% by mass of Zr, and consists of the balance Cu and inevitable impurities. The content of Zn and Zr is represented by the following formula (1):
(1) 0.4 ≦ A + 2B ≦ 1.0
(In the formula, A represents the Zn content (mass%), and B represents the Zr content (mass%).)
Meet. Preferably, the contents of Zn and Zr in the billet are further represented by the following formula (2):
(2) 0.40 ≦ A
(In the formula, A is as defined above.)
And the Zr content is 0.06% by mass or less. Moreover, this billet can also contain P and the content of P in that case is 0.004-0.04 mass%.
本発明の第一の形態の銅合金継目無管の製造方法及び本発明の第二の形態の銅合金継目無管の製造方法では、次いで、該鋳造工程を行うことにより得られたビレットを熱間押出加工する該熱間押出工程を行う。該熱間押出工程では、該熱間押出加工前に該ビレットを所定の温度で加熱した後、該熱間押出加工を行う。該熱間押出加工は、マンドレル押出によって行われる。すなわち、加熱前に、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、熱間押出を行なって、継目無熱間押出素管を得る。 In the method for producing a copper alloy seamless pipe according to the first aspect of the present invention and the method for producing a copper alloy seamless pipe according to the second aspect of the present invention, the billet obtained by performing the casting step is then heated. The hot extrusion step of performing an intermediate extrusion process is performed. In the hot extrusion step, the billet is heated at a predetermined temperature before the hot extrusion, and then the hot extrusion is performed. The hot extrusion process is performed by mandrel extrusion. That is, hot extruding is performed with a mandrel inserted into a billet that has been previously perforated cold before heating, or a billet that has been perforated hot before extrusion to obtain a seamless hot extruded element tube. .
該熱間押出工程の前に、均質化処理を行うことができる。また、該熱間押出加工前のビレットの加熱に、均質化処理を兼ねさせることもできる。 A homogenization treatment can be performed before the hot extrusion step. Further, the heating of the billet before the hot extrusion can be combined with a homogenization treatment.
該熱間押出工程を行うことにより得られた該継目無熱間押出素管を、該熱間押出工程後、速やかに冷却する。該冷却は、該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該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。該熱間押出工程での押出完了時から冷却開始までの時間、すなわち、該ビレットが押出ダイスを通過してから、押し出された該継目無熱間押出素管が最初に冷却水に接触するまでの時間が長過ぎると、この間にＺｒの析出が起こる。そして、このときの析出物は、該時効処理後に析出する析出物に比べ、大きく且つ分散状態もまばらであって、あとのロウ付け加熱時の結晶粒界の移動を阻止する効果はなく、また、あとの時効処理によって微細に析出するためのＺｒを消費してしまうことになり、このような析出を極力避けるべきである。そのため、押出完了時から冷却開始まで時間を極力短くすることが好ましい。具体的には、押出完了時から冷却開始まで時間は、２秒以下が好ましい。 The seamless hot-extrusion tube obtained by performing the hot extrusion step is quickly cooled after the hot extrusion step. The 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. The time from the completion of extrusion in the hot extrusion process to the start of cooling, that is, from when the billet passes through the extrusion die until the extruded seamless hot extrusion tube first comes into contact with the cooling water. If the time is too long, Zr deposition occurs during this time. The precipitates at this time are larger and sparsely dispersed than the precipitates precipitated after the aging treatment, and have no effect of preventing the movement of the grain boundaries during the subsequent brazing heating. Then, Zr for fine precipitation is consumed by the subsequent aging treatment, and such precipitation should be avoided as much as possible. Therefore, it is preferable to shorten the time from the completion of extrusion to the start of cooling as much as possible. Specifically, the time from the completion of extrusion to the start of cooling is preferably 2 seconds or less.
本発明の第一の形態の銅合金継目無管の製造方法及び本発明の第二の形態の銅合金継目無管の製造方法では、次いで、冷却後の継目無押出素管の冷間加工を行い、管の外径及び肉厚を減じていく該冷間加工工程を行う。該冷間加工は、圧延加工や抽伸加工等の冷間加工である。また、該冷間加工工程では、該圧延加工や該抽伸加工等の冷間加工を、複数回行うことができる。なお、本発明の第一の形態の銅合金継目無管の製造方法及び本発明の第二の形態の銅合金継目無管の製造方法では、該冷間加工工程とは、冷間で行う加工の全てを指す。 In the method for manufacturing a copper alloy seamless pipe according to the first aspect of the present invention and the method for manufacturing a copper alloy seamless pipe according to the second aspect of the present invention, cold working of the seamless extruded element pipe after cooling is then performed. And performing the cold working step of reducing the outer diameter and thickness of the tube. The cold working is cold working such as rolling or drawing. In the cold working step, cold working such as rolling and drawing can be performed a plurality of times. In addition, in the manufacturing method of the copper alloy seamless pipe according to the first aspect of the present invention and the manufacturing method of the copper alloy seamless pipe according to the second aspect of the present invention, the cold working step is processing performed cold. Points to all.
該冷間加工工程より後は、本発明の第一の形態の銅合金継目無管の製造方法と、本発明の第二の形態の銅合金継目無管の製造方法とでは、異なるので、それぞれ説明する。 After the cold working step, the first embodiment of the copper alloy seamless pipe manufacturing method of the present invention and the second embodiment of the copper alloy seamless pipe manufacturing method of the present invention are different from each other. explain.
本発明の第一の形態の銅合金継目無管の製造方法では、該冷間加工工程に次いで、該冷間加工工程を行うことにより得られた冷間加工後の継目無素管の時効処理を行う。該時効処理の処理温度は、４００〜６５０℃の温度であり、４００〜６５０℃の処理温度で時効処理を行うことにより、適切なＺｒ系析出物の大きさ及び分布密度や、適切な銅合金の結晶粒度を有する本発明の銅合金継目無管を得る。該時効処理で、該時効処理の処理温度及び処理時間を適宜選択することにより、適切なＺｒ系析出物の大きさ及び分布密度や、適切な銅合金の結晶粒度となるように、調節することができる。 In the method for producing a copper alloy seamless pipe according to the first aspect of the present invention, the aging treatment of the seamless element pipe after the cold working obtained by performing the cold working process subsequent to the cold working process. I do. The treatment temperature of the aging treatment is a temperature of 400 to 650 ° C. By performing an aging treatment at a treatment temperature of 400 to 650 ° C., an appropriate size and distribution density of Zr-based precipitates, an appropriate copper alloy A copper alloy seamless pipe of the present invention having a crystal grain size of In the aging treatment, by appropriately selecting the treatment temperature and treatment time of the aging treatment, the size and distribution density of the appropriate Zr-based precipitates and the appropriate crystal grain size of the copper alloy are adjusted. Can do.
なお、該時効処理を行うためには、該時効処理を行う前に、Ｚｒを銅マトリックスに固溶させるための溶体化処理を行う必要があるが、本発明の第一の形態の銅合金継目無管の製造方法では、該熱間押出工程前の加熱に、該溶解化処理を兼ねさせる。 In order to perform the aging treatment, it is necessary to perform a solution treatment for dissolving Zr in the copper matrix before performing the aging treatment, but the copper alloy joint according to the first aspect of the present invention. In the tubeless manufacturing method, heating before the hot extrusion step is combined with the solubilization treatment.
そして、本発明の第一の形態の銅合金継目無管の製造方法では、該熱間押出工程と該時効処理との間には、中間焼鈍処理を行わず、この間の該冷間加工工程の総加工度（断面減少率）を９０％以上とする。なお、該冷間加工工程の総加工度とは、該冷間加工工程で最初に行う冷間加工前の継目無素管に対する該冷間加工工程で行う最後の冷間加工後の継目無素管の加工度を指し、下記式（４）に示す断面減少率で表す。
断面減少率（％）＝（（管の加工前の断面積−管の加工後の断面積）／（管の加工前の断面積））×１００ （４）
And in the manufacturing method of the copper alloy seamless pipe of the first aspect of the present invention, no intermediate annealing treatment is performed between the hot extrusion step and the aging treatment, and the cold working step in the meantime. The total processing degree (cross-sectional reduction rate) is 90% or more. The total degree of work in the cold working step is the seamless element after the last cold working performed in the cold working step with respect to the seamless pipe before the cold working first performed in the cold working step. It indicates the degree of processing of the tube, and is represented by the cross-sectional reduction rate shown in the following formula (4).
Cross-sectional reduction rate (%) = ((cross-sectional area before processing of pipe−cross-sectional area after processing of pipe) / (cross-sectional area before processing of pipe)) × 100 (4)
本発明の第一の銅合金継目無管の製造方法では、該熱間押出工程を行った後、該時効処理を行う前までの間には、中間焼鈍処理を行わず、且つ、該冷間加工工程の総加工度を上記範囲とすることにより、大きさが０．５〜８０ｎｍの該Ｚｒ系析出物を、分布密度が１０〜６００個／μｍ２で、好ましくは、大きさが０．５〜１０ｎｍの該Ｚｒ系析出物を、分布密度が１００〜６００個／μｍ２で分布させることができ、また、該時効処理後の結晶粒を微細にすること、つまり、該銅合金の平均結晶粒度を３０μｍ以下にすることができる。冷間加工により導入される加工歪は、該時効処理でのＺｒ系析出物の析出場所となるので、該冷間加工の加工度を大きくすることにより、導入される加工歪が均一且つ微細になり、微細で均一なＺｒ系析出物が析出する。 In the first method for producing a copper alloy seamless pipe of the present invention, after the hot extrusion step and before the aging treatment, no intermediate annealing treatment is performed, and the cold treatment is performed. By setting the total degree of processing in the processing step within the above range, the Zr-based precipitates having a size of 0.5 to 80 nm have a distribution density of 10 to 600 / μm 2 , and preferably a size of 0.8. The Zr-based precipitates of 5 to 10 nm can be distributed at a distribution density of 100 to 600 / μm 2 , and the crystal grains after the aging treatment are made fine, that is, the average of the copper alloy The crystal grain size can be 30 μm or less. The processing strain introduced by cold working becomes the precipitation site of Zr-based precipitates in the aging treatment, so that the working strain introduced can be made uniform and fine by increasing the working degree of the cold working. Thus, a fine and uniform Zr-based precipitate is deposited.
このように、本発明の第一の形態の銅合金継目無管の製造方法を行うことにより、該銅合金の平均結晶粒度が３０μｍ以下であり、且つ、大きさが０．５〜８０ｎｍのＺｒ系析出物の分布密度が１０〜６００個／μｍ２である本発明の銅合金継目無管を得ることができる。 Thus, by performing the manufacturing method of the copper alloy seamless pipe of the first aspect of the present invention, the average grain size of the copper alloy is 30 μm or less, and the size is 0.5 to 80 nm. The copper alloy seamless pipe of the present invention in which the distribution density of the system precipitates is 10 to 600 / μm 2 can be obtained.
本発明の第二の形態の銅合金継目無管の製造方法では、該冷間加工工程に次いで、該冷間加工工程を行うことにより得られた冷間加工後の継目無素管を、５００〜８５０℃に加熱する該中間焼鈍処理（Ａ）を行う。該中間焼鈍処理（Ａ）を行うことにより、該転造加工工程での転造加工をし易くする。該中間焼鈍処理（Ａ）における保持温度及び保持時間は、該転造加工工程によって所定の内面溝形成の加工が可能となる最低限の条件、すなわち、できるだけ温度を低く、できるだけ時間を短くすることが好ましい。本発明の第二の形態の銅合金継目無管の製造方法では、該中間焼鈍処理（Ａ）を行った後、該転造加工工程を行うまでは、他の熱処理を行わない。つまり、該中間焼鈍処理（Ａ）は、該転造加工工程の前の熱処理である。 In the method for producing a copper alloy seamless pipe according to the second aspect of the present invention, the cold-worked seamless pipe obtained by performing the cold-working process subsequent to the cold-working process is obtained by This intermediate annealing process (A) heated to 850 degreeC is performed. By performing the intermediate annealing process (A), the rolling process in the rolling process is facilitated. The holding temperature and holding time in the intermediate annealing process (A) are the minimum conditions that allow the predetermined inner surface groove formation by the rolling process, that is, the temperature is as low as possible and the time is as short as possible. Is preferred. In the method for producing a copper alloy seamless pipe according to the second aspect of the present invention, after the intermediate annealing process (A) is performed, no other heat treatment is performed until the rolling process step is performed. That is, the intermediate annealing process (A) is a heat treatment before the rolling process.
本発明の第二の形態の銅合金継目無管の製造方法では、次いで、該中間焼鈍処理（Ａ）後の継目無素管を転造加工する該転造加工工程を行う。該転造加工は、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、該中間焼鈍処理（Ａ）後の継目無素管内に、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、管の外側から押圧して、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（特開２００３−１９１００６号公報参照）。また、通常、該中間焼鈍処理（Ａ）を行った後、縮径加工を行ってから、該転造加工工程を行う。 In the method for manufacturing a copper alloy seamless pipe according to the second aspect of the present invention, the rolling process step of rolling the seamless element pipe after the intermediate annealing treatment (A) is then performed. The rolling process is a process of forming a groove on the inner surface of the pipe material, and a spiral groove is formed on the outer surface of the seamless pipe after the intermediate annealing (A). The rolled plug is placed and pressed from the outside of the tube by a plurality of rolling balls rotating at high speed, and the groove of the rolled plug is transferred to the inner surface of the tube (Japanese Patent Laid-Open No. 2003-191006). See the official gazette). Moreover, after performing this intermediate annealing process (A), after performing a diameter reduction process, this rolling process process is performed.
本発明の第二の形態の銅合金継目無管の製造方法では、次いで、該転造加工工程を行うことにより得られた転造加工後の内面溝付管の時効処理を行う。該時効処理の処理温度は、４００〜６５０℃の温度であり、４００〜６５０℃の処理温度で時効処理を行うことにより、適切なＺｒ系析出物の大きさ及び分布密度や、適切な銅合金の結晶粒度を有する本発明の銅合金継目無管を得る。該時効処理で、該時効処理の処理温度及び処理時間を適宜選択することにより、適切なＺｒ系析出物の大きさ及び分布密度や、適切な銅合金の結晶粒度となるように、調節することができる。 In the method for producing a copper alloy seamless pipe according to the second aspect of the present invention, the inner grooved pipe after the rolling process obtained by performing the rolling process step is then subjected to an aging treatment. The treatment temperature of the aging treatment is a temperature of 400 to 650 ° C. By performing an aging treatment at a treatment temperature of 400 to 650 ° C., an appropriate size and distribution density of Zr-based precipitates, an appropriate copper alloy A copper alloy seamless pipe of the present invention having a crystal grain size of In the aging treatment, by appropriately selecting the treatment temperature and treatment time of the aging treatment, the size and distribution density of the appropriate Zr-based precipitates and the appropriate crystal grain size of the copper alloy are adjusted. Can do.
なお、該時効処理を行うためには、該時効処理を行う前に、Ｚｒを銅マトリックスに固溶させるための溶体化処理を行う必要があるが、本発明の第二の形態の銅合金継目無管の製造方法では、該熱間押出工程前の加熱に、該溶解化処理を兼ねさせる。 In order to perform the aging treatment, it is necessary to perform a solution treatment for dissolving Zr in the copper matrix before performing the aging treatment. However, the copper alloy joint according to the second aspect of the present invention is used. In the tubeless manufacturing method, heating before the hot extrusion step is combined with the solubilization treatment.
そして、本発明の第二の形態の銅合金継目無管の製造方法では、該熱間押出工程と該中間焼鈍処理（Ａ）との間には中間焼鈍処理を行わず、この間の該冷間加工工程の総加工度（断面減少率）を９０％以上とする。なお、該冷間加工工程の総加工度とは、該冷間加工工程で最初に行う冷間加工前の継目無素管に対する該冷間加工工程で最後に行う冷間加工後の継目無素管の加工度を指す。 And in the manufacturing method of the copper alloy seamless pipe of the 2nd form of this invention, an intermediate annealing process is not performed between this hot extrusion process and this intermediate annealing process (A), but this cold between these The total processing degree (section reduction rate) of the processing process is set to 90% or more. The total degree of processing in the cold working step is the seamless element after the cold working performed last in the cold working step with respect to the seamless tube before the cold working performed first in the cold working step. Refers to the degree of processing of the pipe.
本発明の第二の形態の銅合金継目無管の製造方法では、該熱間押出工程を行った後、該中間焼鈍処理（Ａ）を行う前までの間には、中間焼鈍処理を行わず、且つ、該冷間加工工程の総加工度を上記範囲とすることにより、大きさが０．５〜８０ｎｍの該Ｚｒ系析出物を、分布密度が１０〜６００個／μｍ２で、好ましくは、大きさが０．５〜１０ｎｍの該Ｚｒ系析出物を、分布密度が１００〜６００個／μｍ２で分布させることができ、また、該時効処理後の結晶粒を微細にすること、つまり、該銅合金の平均結晶粒度を３０μｍ以下にすることができる。冷間加工により導入される加工歪は、該時効処理でのＺｒ系析出物の析出場所となるので、該冷間加工の加工度を大きくすることにより、導入される加工歪が均一且つ微細になり、微細で均一なＺｒ系析出物が析出する。また、該中間焼鈍処理（Ａ）を行うことにより、銅合金は再結晶するが、その再結晶粒をできるだけ微細な状態にしておくためには、このような均一且つ微細な加工歪をできる限り保持させるために、該熱間押出工程を行った後、該中間焼鈍処理（Ａ）を行う前までの間には中間焼鈍処理を行わない。 In the method for producing a copper alloy seamless pipe according to the second aspect of the present invention, the intermediate annealing treatment is not performed after the hot extrusion step and before the intermediate annealing treatment (A). And, by setting the total degree of processing in the cold working step within the above range, the Zr-based precipitates having a size of 0.5 to 80 nm, preferably having a distribution density of 10 to 600 / μm 2 , The Zr-based precipitates having a size of 0.5 to 10 nm can be distributed at a distribution density of 100 to 600 / μm 2 , and the crystal grains after the aging treatment are made fine, The average grain size of the copper alloy can be 30 μm or less. The processing strain introduced by cold working becomes the precipitation site of Zr-based precipitates in the aging treatment, so that the working strain introduced can be made uniform and fine by increasing the working degree of the cold working. Thus, a fine and uniform Zr-based precipitate is deposited. In addition, the copper alloy is recrystallized by performing the intermediate annealing treatment (A), but in order to keep the recrystallized grains as fine as possible, such uniform and fine processing strain is possible as much as possible. In order to hold, after performing this hot extrusion process, it does not perform an intermediate annealing process before performing this intermediate annealing process (A).
このように、本発明の第二の形態の銅合金継目無管の製造方法に行うことにより、該銅合金の平均結晶粒度が３０μｍ以下であり、且つ、大きさが０．５〜８０ｎｍのＺｒ系析出物の分布密度が１０〜６００個／μｍ２である本発明の銅合金継目無管を得ることができる。 Thus, by carrying out to the method for producing a copper alloy seamless pipe according to the second aspect of the present invention, the copper alloy has an average crystal grain size of 30 μm or less and a Zr of 0.5 to 80 nm in size. The copper alloy seamless pipe of the present invention in which the distribution density of the system precipitates is 10 to 600 / μm 2 can be obtained.
本発明の銅合金継目無管のうち内面平滑管は、コイル状に巻き取られ、主として、冷媒配管用に供される。また、本発明の銅合金継目無管のうち内面溝付管は、コイル形状に巻き取られ、熱交換器用の伝熱管としてクロスフィンチューブ型熱交換器の作製に供される。 Among the copper alloy seamless pipes of the present invention, the inner smooth pipe is wound in a coil shape and is mainly used for refrigerant piping. In addition, the inner grooved tube of the copper alloy seamless tube of the present invention is wound into a coil shape and used for the production of a cross fin tube type heat exchanger as a heat transfer tube for a heat exchanger.
＜本発明の銅合金継目無管が、クロスフィンチューブ型熱交換器用の伝熱管に供される場合＞
該クロスフィンチューブ型熱交換器は、空気側のアルミニウムプレートフィンと冷媒側の伝熱管が、一体に組付けられて構成されている。
該クロスフィンチューブ型熱交換器の製造工程について説明する。該クロスフィンチューブ型熱交換器の製造工程では、先ず、プレス加工等により、所定の組付け孔が複数形成されたアルミニウムプレートフィンを作製する。
次いで、得られたアルミニウムプレートフィンを積層した後、該組付け孔の内部に、伝熱管を挿通する。該伝熱管は、該転造加工工程によって内面に溝が形成された本発明の銅合金継目無管を、定尺切断及びヘアピン曲げを加工して作製される。
次いで、該伝熱管を、該アルミニウムプレートフィンに拡管固着し、ヘアピン曲げ加工を施した側とは反対側の伝熱管端部を拡管加工して、Ｕベンド管を挿通後、ロウ付けして、熱交換器を作製する。
<When the copper alloy seamless pipe of the present invention is used in a heat transfer tube for a cross fin tube type heat exchanger>
The cross fin tube type heat exchanger is configured by integrally assembling an air side aluminum plate fin and a refrigerant side heat transfer tube.
A manufacturing process of the cross fin tube heat exchanger will be described. In the manufacturing process of the cross fin tube type heat exchanger, first, an aluminum plate fin in which a plurality of predetermined assembly holes are formed is produced by pressing or the like.
Next, after stacking the obtained aluminum plate fins, a heat transfer tube is inserted into the assembly hole. The heat transfer tube is produced by subjecting the copper alloy seamless tube of the present invention in which grooves are formed on the inner surface by the rolling process, to a regular cutting and hairpin bending.
Next, the heat transfer tube is expanded and fixed to the aluminum plate fin, the end of the heat transfer tube opposite to the side subjected to the hairpin bending process is expanded, the U-bend tube is inserted, brazed, Make a heat exchanger.
このような製造工程中で、継目無管は、ヘアピン曲げ加工や管端拡管加工という強加工が施されるため、加工性が良好であることが必要である。加工性が良好であることの裏返しとして、強度が高過ぎないことが望まれる。このためには、継目無管には、ロウ付けによる強度低下が極力小さいことが好ましい。特に、本発明の銅合金継目無管のうち、該銅合金の平均結晶粒度が３０μｍ以下であり、且つ、大きさが０．５〜８０ｎｍのＺｒ系析出物の分布密度が１０〜６００個／μｍ２である銅合金継目無管によれば、上述したように、Ｚｒ系析出物の大きさ及び分散密度が適切化されているために、ロウ付けによる強度低下が小さい。 In such a manufacturing process, the seamless tube is subjected to strong processing such as hairpin bending processing and tube end tube expansion processing, and therefore, it is necessary that the workability is good. As a flip side of good workability, it is desirable that the strength is not too high. For this purpose, it is preferable that the strength reduction due to brazing is as small as possible in the seamless pipe. Particularly, in the copper alloy seamless pipe of the present invention, the average grain size of the copper alloy is 30 μm or less and the distribution density of Zr-based precipitates having a size of 0.5 to 80 nm is 10 to 600 / According to the copper alloy seamless pipe of μm 2 , as described above, since the size and dispersion density of the Zr-based precipitates are appropriate, the strength reduction due to brazing is small.
＜本発明の銅合金継目無管が、冷媒配管用に供される場合＞
冷媒配管としては、例えば、二酸化炭素冷媒を用いた給湯機においては、ヒートポンプサイクルを構成する圧縮機、蒸発器、膨張弁、放熱器を接続する配管に用いられる。このような配管接続部においては、一方の管端を拡管し、もう一方の管端をこの拡管部に挿入した後、ロウ付けを行うことによって作製される。この場合も、伝熱管として使用される場合と同様に、管端拡管加工という強加工が
施されるため、加工性が良好であることが必要である。
<When the copper alloy seamless pipe of the present invention is used for refrigerant piping>
As a refrigerant pipe, for example, in a water heater using a carbon dioxide refrigerant, it is used as a pipe connecting a compressor, an evaporator, an expansion valve, and a radiator that constitute a heat pump cycle. Such a pipe connection part is produced by expanding one pipe end and inserting the other pipe end into the expanded pipe part, followed by brazing. Also in this case, as in the case of being used as a heat transfer tube, it is necessary to have good workability because it is subjected to strong processing called tube end tube expansion processing.
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.
本発明の継目無管のうち、内面平滑管の例について説明する。
実施例１（Ｎｏ．１〜８、１４、１５）及び比較例１（Ｎｏ．９〜１３）
Ｃｕ、Ｚｎの地金又はスクラップ、並びにＣｕ−Ｚｒ母合金及びＣｕ−Ｐ母合金を用いて、表１に示す成分に配合し、高周波溶解炉を用いて径２５４ｍｍの鋳塊を製造した。
次いで、該鋳塊を９３０℃に加熱した後、この温度で、熱間押出を行い、外径８１ｍｍ×肉厚８ｍｍ管（押出素管）とした。なお、熱間押出を、水中押出にて行った。また、熱間押出前の加熱にて溶体化処理を兼ねた。
次いで、冷間圧延及び冷間抽伸を行い、外径９．５２ｍｍ×肉厚０．８ｍｍ管（冷間抽伸管）を得た。
次いで、バッチ炉内にて、非酸化性雰囲気中で、６００℃で３０分間の時効処理を行い、継目無管を得た。
なお、熱間押出と時効処理との間には、中間焼鈍を行っていない。また、このとき、冷間圧延及び冷間抽伸の合計の冷間加工度、すなわち、冷間加工工程の総加工度（断面減少率）は９８．８％であった。
Among the seamless pipes of the present invention, an example of the inner smooth pipe will be described.
Example 1 (No. 1-8, 14, 15) and Comparative Example 1 (No. 9-13)
An ingot having a diameter of 254 mm was manufactured using a high frequency melting furnace using Cu, Zn ingots or scraps, and a Cu-Zr master alloy and a Cu-P master alloy and blending them into the components shown in Table 1.
Next, the ingot was heated to 930 ° C., and then hot extrusion was performed at this temperature to obtain a tube having an outer diameter of 81 mm × a wall thickness of 8 mm (extrusion element tube). In addition, hot extrusion was performed by underwater extrusion. Moreover, it also served as a solution treatment by heating before hot extrusion.
Subsequently, cold rolling and cold drawing were performed to obtain a tube having an outer diameter of 9.52 mm and a wall thickness of 0.8 mm (cold drawing tube).
Next, an aging treatment was performed at 600 ° C. for 30 minutes in a non-oxidizing atmosphere in a batch furnace to obtain a seamless tube.
In addition, intermediate annealing is not performed between hot extrusion and aging treatment. At this time, the total cold working degree of cold rolling and cold drawing, that is, the total working degree (cross section reduction rate) of the cold working step was 98.8%.
（評価）
１．ロウ付け前の継目無管の組織
＜平均結晶粒度＞
実施例１及び比較例１の継目無管について、管の円周方向断面において、ＪＩＳ Ｈ０５０１に定められた比較法を用いて結晶粒度を測定し、任意の１０ヶ所の平均した値を平均結晶粒度とした。その結果を表２に示す。
(Evaluation)
1. Seamless tube structure before brazing <average grain size>
For the seamless pipes of Example 1 and Comparative Example 1, the crystal grain size was measured using the comparison method defined in JIS H0501 in the circumferential cross section of the pipe, and the average grain size was obtained by averaging 10 arbitrary values. It was. The results are shown in Table 2.
＜Ｚｒ系析出物の分布密度＞
透過型電子顕微鏡観察により、Ｚｒ系析出物の分布密度の評価を行った。
電子顕微鏡観察用の試料の調整は、前記実施例１及び比較例１の継目無管より切り出した試料を、まずエメリー紙を用いた湿式研磨により厚さ０．２ｍｍとし、その後、リン酸とメタノールを体積比１：３の割合で混合した溶液を用いて電解研磨を行って薄膜とした。
そして、得られた薄膜を、加速電圧２００ｋＶにて透過型電子顕微鏡観察を行った。
透過型電子顕微鏡観察では、倍率２００００倍で撮影した電子顕微鏡写真の、０．５μｍ×０．４μｍの視野から、大きさ０．５〜８０ｎｍの析出物の数及び大きさ０．５〜１０ｎｍの析出物の数をカウントした。析出物のカウントの際には、等厚干渉縞を用いた膜厚測定法により、膜厚変化が線形との仮定のもと、平均膜厚を求め、体積率を面積率に換算した。
なお、Ｚｒ系析出物は円盤状の形態を示すものがあり、電子顕微鏡写真では、細長い形状に撮影されることがある。このため、１個の析出物像にて一番長い径（長径）をその析出物の大きさとした。
また、析出物の数をカウントするに際し、数が２００個を超えるようなものについては、０．５μｍ×０．４μｍの視野の中から、倍率１０万倍で撮影した、さらに狭い視野０．１μｍ×０．０８μｍを３箇所、任意に選んで、その視野にて析出物のカウントを行い、その平均値にて評価した。
析出物の密度を下記ランクにて評価した。
ランク１：１０個／μｍ2未満
ランク２：１０〜１００個／μｍ2
ランク３：１００〜６００個／μｍ2
ランク４：６００個／μｍ2超え
なお、大きさ０．５〜８０ｎｍの析出物の密度は、ランク２、ランク３が本発明の範囲に該当する。その結果を表２に示す。
<Distribution density of Zr-based precipitates>
The distribution density of the Zr-based precipitates was evaluated by observation with a transmission electron microscope.
Preparation of the sample for electron microscope observation was carried out by first cutting the sample cut from the seamless tube of Example 1 and Comparative Example 1 to a thickness of 0.2 mm by wet polishing using emery paper, and then phosphoric acid and methanol. Was subjected to electropolishing using a solution in which the volume ratio of 1: 3 was mixed to form a thin film.
The obtained thin film was observed with a transmission electron microscope at an acceleration voltage of 200 kV.
In the transmission electron microscope observation, the number of precipitates having a size of 0.5 to 80 nm and the number of precipitates having a size of 0.5 to 10 nm from the field of view of 0.5 μm × 0.4 μm of an electron micrograph taken at a magnification of 20000 times. Counted. When counting the precipitates, an average film thickness was determined by a film thickness measurement method using equal thickness interference fringes under the assumption that the film thickness change was linear, and the volume ratio was converted into an area ratio.
Note that some Zr-based precipitates have a disk shape, and may be photographed in an elongated shape in an electron micrograph. For this reason, the longest diameter (major axis) in one precipitate image is the size of the precipitate.
Further, when counting the number of precipitates, those with a number exceeding 200 were photographed at a magnification of 100,000 times from a field of view of 0.5 μm × 0.4 μm, and a narrow field of view of 0.1 μm × 0. .08 μm was arbitrarily selected at three locations, the precipitates were counted in the field of view, and the average value was evaluated.
The density of the precipitate was evaluated according to the following rank.
Rank 1: Less than 10 / μm 2 Rank 2: 10-100 / μm 2
Rank 3: 100-600 / μm 2
Rank 4: Over 600 / μm 2 Note that the density of precipitates having a size of 0.5 to 80 nm corresponds to the scope of the present invention in ranks 2 and 3. The results are shown in Table 2.
２．加工性
ロウ付け前の継目無管を、円錐状のプラグによる拡管試験により、加工性試験を行った。管端の外径を拡管前の外径の３倍まで拡管した後も、割れが生じなかったものを合格「○」とし、割れが生じたものを不合格「×」とした。その結果を表２に示す。
2. Processability A seamless pipe before brazing was subjected to a workability test by a pipe expansion test using a conical plug. Even when the outer diameter of the pipe end was expanded to 3 times the outer diameter before the expansion, the case where no crack occurred was regarded as a pass “◯”, and the case where the crack occurred was regarded as a disqualification “x”. The results are shown in Table 2.
３．ロウ付け前後の機械的性質
ロウ付け時の管の温度上昇と同等の条件として、８００℃で３０秒間の加熱を行い、その加熱前後の機械的性質（引張強さと伸び）を評価した。
引張試験により機械的性質を評価し、ＪＩＳ Ｚ２２４１に準じ、引張強さと伸びを測定した。その結果を、表２に示す。
3. Mechanical properties before and after brazing As conditions equivalent to the temperature rise of the tube during brazing, heating was performed at 800 ° C. for 30 seconds, and mechanical properties (tensile strength and elongation) before and after the heating were evaluated.
Mechanical properties were evaluated by a tensile test, and tensile strength and elongation were measured according to JIS Z2241. The results are shown in Table 2.
実施例２（Ｎｏ．１６〜１８）
表３に示す化学成分の鋳塊を用い、次いで、該鋳塊を９３０℃の適宜の温度に加熱した後、この温度で、熱間押出を行い、外径８１ｍｍ×肉厚８ｍｍ管（押出素管）とした。なお、熱間押出を、水中押出にて行った。また、熱間押出前の加熱にて溶体化処理を兼ねた。
次いで、冷間圧延及び冷間抽伸を行い、外径９．５２ｍｍ×肉厚０．８ｍｍ管（冷間抽伸管）を得た。
次いで、バッチ炉内にて、非酸化性雰囲気中で、表３に示す処理条件で時効処理を行い、継目無管を得た。
なお、Ｎｏ．１６〜１８では、熱間押出と時効処理との間には、中間焼鈍を行っていない。
また、このとき、冷間圧延及び冷間抽伸の合計の冷間加工度、すなわち、冷間加工工程の総加工度（断面減少率）を、表３に示す。
Example 2 (No. 16-18)
Using the ingots of chemical components shown in Table 3, the ingot was then heated to an appropriate temperature of 930 ° C., and then hot extrusion was carried out at this temperature to obtain an outer diameter 81 mm × thickness 8 mm tube (extruded element). Tube). In addition, hot extrusion was performed by underwater extrusion. Moreover, it also served as a solution treatment by heating before hot extrusion.
Subsequently, cold rolling and cold drawing were performed to obtain a tube having an outer diameter of 9.52 mm and a wall thickness of 0.8 mm (cold drawing tube).
Next, an aging treatment was performed in a batch furnace in a non-oxidizing atmosphere under the treatment conditions shown in Table 3 to obtain a seamless tube.
In addition, No. In 16-18, intermediate annealing is not performed between hot extrusion and aging treatment.
Further, at this time, the total cold working degree of cold rolling and cold drawing, that is, the total working degree (cross section reduction rate) of the cold working step is shown in Table 3.
（評価）
ロウ付け前の継目無管の組織（平均結晶粒度、Ｚｒ系析出物の分布密度）、加工性及びロウ付け前後の継目無管の機械的性質については、実施例１及び比較例１と同様に評価を行った。その結果を表４に示す。
(Evaluation)
The seamless pipe structure before brazing (average grain size, Zr-based precipitate distribution density), workability, and mechanical properties of the seamless pipe before and after brazing are the same as in Example 1 and Comparative Example 1. Evaluation was performed. The results are shown in Table 4.
本発明の銅合金継目無管のうち、内面溝付管について説明する。
実施例３（Ｎｏ．１９、２０）
Ｃｕ、Ｚｎの地金又はスクラップ、並びにＣｕ−Ｚｒ母合金及びＣｕ−Ｐ母合金を用いて、表５に示す化学成分の鋳塊を用い、次いで、該鋳塊を９３０℃に加熱した後、この温度で、熱間押出を行い、外径８１ｍｍ×肉厚８ｍｍ管（押出素管）とした。なお、熱間押出を、水中押出にて行った。また、熱間押出前の加熱にて溶体化処理を兼ねた。
次いで、冷間圧延及び冷間抽伸を行い、外径９．５ｍｍ×肉厚０．５ｍｍ管（冷間抽伸管）を得た。
次いで、下記条件で中間焼鈍（Ａ）を行った。
＜中間焼鈍（Ａ）の条件＞
５００℃から７３０℃までの最小昇温速度：１０℃／秒
最高到達温度：８００℃
７５０℃〜８００℃での保持時間：２秒
７３０℃から５００℃までの最小冷却速度：１０℃／秒
次いで、転造加工を行い、外径７ｍｍの内面溝付管を得た。得られた内面溝付管の寸法諸元を表７に示す。
Of the copper alloy seamless pipe of the present invention, an inner grooved pipe will be described.
Example 3 (No. 19, 20)
Using ingots of chemical components shown in Table 5 using Cu, Zn bullion or scrap, and Cu-Zr master alloy and Cu-P master alloy, and then heating the ingot to 930 ° C, At this temperature, hot extrusion was performed to obtain an outer diameter 81 mm × thickness 8 mm tube (extrusion tube). In addition, hot extrusion was performed by underwater extrusion. Moreover, it also served as a solution treatment by heating before hot extrusion.
Subsequently, cold rolling and cold drawing were performed to obtain a tube having an outer diameter of 9.5 mm and a wall thickness of 0.5 mm (cold drawing tube).
Next, intermediate annealing (A) was performed under the following conditions.
<Conditions for intermediate annealing (A)>
Minimum heating rate from 500 ° C to 730 ° C: 10 ° C / second Maximum temperature reached: 800 ° C
Holding time at 750 ° C. to 800 ° C .: 2 seconds Minimum cooling rate from 730 ° C. to 500 ° C .: 10 ° C./second Subsequently, a rolling process was performed to obtain an internally grooved tube having an outer diameter of 7 mm. Table 7 shows the dimensions of the obtained internally grooved tube.
次いで、バッチ炉内にて、非酸化性雰囲気中で、６００℃で３０分間の時効処理を行い、継目無管を得た。
なお、熱間押出と中間焼鈍（Ａ）との間には、中間焼鈍を行っていない。また、このとき、冷間圧延及び冷間抽伸の合計の冷間加工度、すなわち、冷間加工工程の総加工度（断面減少率）は９９．２％であった。
Next, an aging treatment was performed at 600 ° C. for 30 minutes in a non-oxidizing atmosphere in a batch furnace to obtain a seamless tube.
In addition, intermediate annealing is not performed between hot extrusion and intermediate annealing (A). At this time, the total cold working degree of cold rolling and cold drawing, that is, the total working degree (cross-sectional reduction rate) of the cold working step was 99.2%.
（評価）
ロウ付け前の継目無管の組織（平均結晶粒度、Ｚｒ系析出物の分布密度）、加工性及びロウ付け前後の継目無管の機械的性質については、実施例１及び比較例１と同様に評価を行った。その結果を表６に示す。
(Evaluation)
The seamless pipe structure before brazing (average grain size, Zr-based precipitate distribution density), workability, and mechanical properties of the seamless pipe before and after brazing are the same as in Example 1 and Comparative Example 1. Evaluation was performed. The results are shown in Table 6.
熱交換器等の耐圧強度設計においては、ロウ付け熱影響部の材料強度を元に管の肉厚を決める。そして、本発明の銅合金継目無管は、強度が高く且つロウ付けによる強度低下が少ないので、本発明によれば、伝熱管、冷媒管の薄肉化が可能となるとともに、ロウ付け熱影響のない部分で、不必要な強度向上がなく、その裏返しとしての加工性低下が抑制されることによって、良好な加工性を確保することが可能となる。 In the pressure strength design of a heat exchanger or the like, the thickness of the pipe is determined based on the material strength of the brazed heat-affected zone. Since the copper alloy seamless pipe of the present invention has high strength and little strength reduction due to brazing, according to the present invention, it is possible to reduce the thickness of the heat transfer pipe and the refrigerant pipe, and to reduce the influence of brazing heat. It is possible to ensure good workability by preventing unnecessary improvement in strength at a portion where there is not, and suppressing deterioration of workability as the reverse.
ｔ 肉厚
ｈ フィン高さ
α フィン頂角
t Thickness h Fin height α Fin apex angle
Claims (4)
該銅合金は、Ｚｎと、０．０１〜０．０８質量％のＺｒと、を含有し、残部Ｃｕ及び不可避不純物からなり、
該銅合金中のＺｎ及びＺｒの含有量が、下記式（１）：
（１）０．４≦Ａ＋２Ｂ≦１．０
（式中、ＡはＺｎの含有量（質量％）を示し、ＢはＺｒの含有量（質量％）を示す。）
を満たすこと、
を特徴とする銅合金継目無管。 It is a copper alloy seamless pipe obtained by processing a copper alloy,
The copper alloy contains Zn and 0.01 to 0.08% by mass of Zr, and consists of the balance Cu and inevitable impurities,
The content of Zn and Zr in the copper alloy is represented by the following formula (1):
(1) 0.4 ≦ A + 2B ≦ 1.0
(In the formula, A represents the Zn content (mass%), and B represents the Zr content (mass%).)
Meeting,
Copper alloy seamless pipe characterized by
（２）０．４０≦Ａ
（式中、Ａは、前記と同義である。）
を満たし、且つ、Ｚｒの含有量が０．０６質量％以下であることを特徴とする請求項１記載の銅合金継目無管。 The content of Zn and Zr in the copper alloy is further reduced to the following formula (2):
(2) 0.40 ≦ A
(In the formula, A is as defined above.)
The copper alloy seamless pipe according to claim 1, wherein the Zr content is 0.06% by mass or less.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013221172A (en) * | 2012-04-16 | 2013-10-28 | Sumitomo Light Metal Ind Ltd | Level wound coil, method for manufacturing the level wound coil, cross fin tube type heat exchanger, and method for manufacturing the cross fin tube type heat exchanger |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2013221172A (en) * | 2012-04-16 | 2013-10-28 | Sumitomo Light Metal Ind Ltd | Level wound coil, method for manufacturing the level wound coil, cross fin tube type heat exchanger, and method for manufacturing the cross fin tube type heat exchanger |
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