COPPER ALLOY TUBE EXCELLENT IN HIGH TEMPERATURE BRAZABILITY AND MANUFACTURING METHOD THEREFOR

PROBLEM TO BE SOLVED: To provide a copper alloy tube excellent in high temperature brazability by suppressing deterioration of mechanical strength even in a temperature zone of a solution treatment, especially coarsening of crystal particles in a drawing processed tube of a CuCrZr alloy.SOLUTION: There is provided a manufacturing method of a copper alloy tube including a main processing consisting of a solution process for water hardening by heating and holding a tubular extrusion material of a CrZrCu alloy containing, by mass%, Cr of 0.5 to 1.5%, Zr of 0.02 to 0.20% and the balance Cu with inevitable impurities at a solution temperature of 900°C or more, drawing processing process for drawing processing and an intermediate annealing process for annealing the same and water hardening, and an adjustment processing for making average crystal particle diameter of 50 μm or less on a longitudinal section along an axis line of the drawing processing and a transverse section vertical to the axis line respectively, and average crystal particle diameters of the longitudinal section and the transverse section respectively after solution process respectively are 100 μm or more and average crystal particle diameters of the longitudinal section and the transverse section are 100 μm or less respectively even when an annealing temperature is 900°C or more and the tubular extrusion material is cooled after heating at least 980°C for 30 min. after a second processing process.SELECTED DRAWING: Figure 2 【課題】ＣｕＣｒＺｒ合金の引抜加工管で、溶体化処理の温度帯でも機械強度の劣化、特に結晶粒の粗大化を抑制し、高温ロウ付け性に優れる銅合金管及びその製造方法の提供。【解決手段】質量％で、Ｃｒを０．５〜１．５％、Ｚｒを０．０２〜０．２０％、残部を不可避的不純物及びＣｕとするＣｒＺｒＣｕ合金の管状押出材を９００℃以上の溶体化温度で加熱保持して水焼き入れする溶体化工程、引抜加工する引抜加工工程及びこれを焼鈍して水焼き入れする中間焼鈍工程からなる主加工と、引抜加工の軸線に沿った縦断面及び軸線に垂直な横断面の夫々での平均結晶粒径を５０μｍ以下とする調整加工とを含み、溶体化工程後に縦断面及び横断面の各平均結晶粒径を１００μｍ以上とし、焼鈍温度を９００℃以上として、二次加工工程後に、少なくとも９８０℃で３０分間の加熱後空冷しても縦断面及び横断面での平均結晶粒径が１００μｍ以下である銅合金管の製造方法。【選択図】図２