大规格铜镍合金无缝管材成品退火工艺研究

Study on Annealing Process of Large Size Copper Nickel Alloy Tube

选用6个典型规格的铜镍合金无缝管材经拉拔生产后,按拟定的退火试验方案进行退火试验,退火后取样进行性能测试。通过检测拉伸强度、屈服强度和伸长率,以及布什硬度和洛氏硬度,并进行金相试验,观察合金是否由加工态组织变为单相再结晶α组织。结果表明:小于等于700℃的退火温度无法保证获得完全再结晶的单相α组织。退火温度大于730℃只会让晶粒持续长大;退火保温时间小于等于30 min无法实现全部再结晶,大于40 min,只会让晶粒持续长大。(720±10)℃保温40 min是比较适宜的铜镍合金无缝管材退火工艺制度。

The annealing process of copper nickel alloy seamless pipe was studied. Six typical copper nickel alloy seamless tubes were selected and produced by drawing. The annealing test was carried out according to the proposed annealing test scheme. After annealing, samples were taken for performance test. By testing tensile strength, yield strength and elongation, as well as Bush hardness and Rockwell hardness, and carrying out metallographic test, that whether the microstructure change from processed state to single-phase recrystallized α structure was observed. When the annealing temperature was less than or equal to 700 ℃, it was impossible to obtain single-phase α structure with complete recrystallization. When the annealing temperature was higher than 730 ℃, the grains would grow continuously. Annealing holding time less than or equal to 30 minutes could not achieve all recrystallization, and more than 40 minutes could make the grain continue to grow. The optimal annealing process for seamless copper nickel alloy pipe was holding at(720±10) ℃ for 40 minutes.