铜管弯曲缺陷分析及退火工艺优化

Bending defects analysis and annealing process optimization of air-conditioner copper tube

内皱是薄壁铜管弯曲过程中的一种常见缺陷。采用有限元软件并结合内皱样品微观组织分析了铜管产生内皱原因。对不同退火工艺条件下铜管的微观组织进行了表征,优化了铜管的退火工艺。研究结果表明:在弯曲变形的起始阶段,铜管内侧质点发生螺旋运动,铜管内皱处可见粗大晶粒,质点的螺旋运动和粗大晶粒易导致铜管弯曲时产生内皱,这与实际变形结果较为一致。在500℃、33 min退火时铜管微观组织细小均匀,对其进行现场弯曲试验,没有内皱缺陷,并获得了优良的小弯头管。

The inner wrinkle is a kind of frequent defects during the bending of thin-wall copper tube.The causing reason of copper tube inner wrinkle defects was analyzed by finite element software and inner wrinkle sample microstructure.The microstructure was characterized at different annealing process and then the annealing process was optimized.These research results showed that the spiral motion of particle occurred at medial tube at the beginning of bending.The coarse grain obviously appeared at the wrinkle.The spiral motion of particle and the coarse grain would easily cause the wrinkle of tube,it meets with the actual bending results.The copper with fine and uniform structure was obtained by annealing at 500℃,33 min and was bended at site,and the excellent elbow tubes were obtained without the defect of inside wrinkle.