球形阀芯缩口工件的焊接三维数值模拟

3-D numerical simulation of welding spherical valve core

在采用圆管缩口-压装-焊接-磨削的方法加工球形阀芯时,焊接是关键的一环.因缩口工件焊接前塑性加工产生了应力场,且焊后还要进行机械加工,故如何优化焊接工艺参数以保证在焊透的前提下控制焊后残余应力成为有待解决的问题.文中以MSC MARC为平台,对球形阀芯缩口工件的焊接进行了实时动态的三维数值模拟,通过比较不同工艺参数下的焊缝尺寸及焊后残余应力优化了焊接工艺参数.结果表明,模拟的可靠性;对于焊接前塑性加工过的工件,其焊后的残余应力场是多个塑性加工工序应力场的叠加.

Welding is the key course in manufacturing the spherical valve core through steel tube's necking,assembling,welding and grinding.Because the necked workpiece is under stress before welding and is to be prepared for grinding after welding,how to choose sound welding parameters so as to control residual stress with the precondition of excellent weld quality becomes the focus of this paper.A series of numerical simulations which show the real-time dynamic changes under different welding parameters for necked workpiece are demonstrated,and the optimization parameters are obtained through comparing the welding size and residual stress after welding.Analysis and illustrations on the accumulated results show that the residual stress after welding is overlapped in the former procedures.