成形工艺对冷弯方管残余应力及焊接微观组织的影响  

Effect of Forming Processes on Residual Stresses and Weld Microstructure of Roll-Formed Square Tube

作　　者：李茜[1] 韩飞[1] 杨河[1] 

机构地区：[1]北方工业大学机电工程学院,北京100144

出　　处：《钢铁研究学报》2014年第1期37-42,共6页Journal of Iron and Steel Research

摘　　要：冷弯方管成形有"直接成方"和"圆成方"两种方式。为了研究成形工艺对于产品的不同影响,以规格为100mm×100mm×6mm,材料为Q235的两种成形工艺的方管为研究对象,采用钻孔法对方管各个部位的残余应力进行了测量,并观测了焊缝处的显微组织。研究结果表明,不同成形工艺对纵向残余应力的分布影响较大,焊缝处的残余应力最大。"圆成方"过程中施加较大的焊接压力使得其焊接热影响区宽度小于"直接成方"工艺条件下焊接热影响区的宽度,且抑制了奥氏体晶粒长大,冷却后获得较为细小均匀的晶粒。There are two forming methods to produce roll formed square tube in general, namely Flat-strip-to- Square Forming （FRF） and Circle-to-Square Forming （CRF）. To observe the different effects of forming method on their production, a hole-drilling residual stress test was carried out to obtain the residual stresses in the two kinds of Q235 square tube with dimensions of 100 mm ×100 mm× 6 mm. The distribution of residual stresses at different positions were then measured and studied. In addition, the microstructure of their welding area was ana- lyzed. The results show that forming process has a significant effect on the distribution of longitudinal residual stresses. Residual stresses in welding area are found to be the largest through the section in both kinds of tube. Due to welding pressure applied in the forming process of CRF tube, heat-affected area of CRF tube is smaller than that of FRF tube. The pressure restrains the growth of austenite when welding, which in turn fines crystal- line grain after cooling.

关 键 词：方管 成形工艺 残余应力 微观组织 

分 类 号：TG457.6[金属学及工艺—焊接] TG115