外加横向磁场对304不锈钢焊接熔池影响机理分析

Analysis of influence mechanism of external transverse magnetic field on welding pool of 304 stainless steel

为了改善焊缝成形及提高焊接零件组织和性能,文中采用有限元法对外加磁场作用下的304不锈钢焊接熔池进行电磁场和热流场之间的耦合分析,得到了有无外加横向磁场作用下熔池内液态金属流动的速度矢量分布.结果表明,外加磁场使熔池横截面最大流速分布由单一的熔池中心中部改为熔池中心上表面略靠下和熔池底部;熔池纵截面最大流速由首尾端漩涡交汇处改为沿两个漩涡流动方向较均匀分布,这是由于电磁压力抵消了部分表面张力,使表面张力的作用位置更靠近熔池中心位置.在304不锈钢上进行堆焊试验,焊道横截面组织形貌证实了上述模拟结果.

In order to improve the weld forming and the performance of welded parts,the coupling analysis between electromagnetic field and thermal flow field of 304 stainless steel weld pool under external magnetic field is carried out by finite element method in this paper,and the velocity vector distribution of liquid metal flow in weld pool under magnetic field and without magnetic field is obtained.The results show that the maximum velocity distribution in the cross section of the molten pool is changed from a single central part to a slightly lower upper surface and the bottom of the molten pool,and the maximum velocity distribution on longitudinal section is not only located at the vortex junction of the front molten pool and the tail molten pool but along two vortex flow direction more uniformly distributed.This is because the electromagnetic pressure offset part of the effect of surface tension,and the electromagnetic pressure makes the acting position of the surface tension is more close to the center of the molten pool and away from the edge of workpiece.The building-up welding test on 304 stainless steel is carried out,and the phase diagram of cross section of the welding confirms the above simulation results.