磁场作用下铝/钢CMT焊接温度场及熔池流动行为

Effect of Magnetic Field on the Weld Temperature Field and Flow Behavior of Molten Pool in Al/Steel CMT Welding Process

为探究纵向磁场在铝/钢冷金属过渡(Cold metal transfer,CMT)焊接过程中的作用机理,采用ANSYS软件对纵向磁场作用下电弧形态、温度分布和熔池流动行为进行数值模拟,重点研究不同线圈励磁电流对焊接温度场和熔池流动行为的影响。结果表明,外加磁场可以改变电弧等离子体的运动行为,进而影响了焊接电弧在基板表面和熔池内部的热量传导行为。施加磁场后,熔池中的峰值温度发生下降,峰值温度区域由熔池中心转向熔池外围,铝/钢界面处的高温停留时间和温度也随之下降。此外,外加磁场改变了铝液熔池内部的流动行为。熔池内部的流动特征由无磁场时的单一环流,转变为有磁场作用时的双环流流动特征。随着励磁电流的增加,熔池内部的流速和流动范围有增大的趋势。

In order to investigate the effect mechanism of longitudinal magnetic field on the Al/Steel cold metal transfer(CMT) welding process,the morphology and temperature distribution of weld arc and the flow behavior of molten pool are simulated by ANSYS software in present work.The results show that the external magnetic field(EMF) could change the movement of arc plasma,and ultimately affected the arc shape as well as the heat conduction behavior from weld arc to the molten pool and base plate.With application of EMF,the peak temperature of molten pool decreases,and the high-temperature zone moves from the center of molten pool to the lateral,which decreases the reaction temperature and retention time of high-temperature at the front interface of Al/steel joint.Besides that,the application of EMF also changes the flow behavior of molten pool.The flow behavior inside the molten pool changes from the single circulation into a double circulation flow characteristics by application of EMF.With the increase of core exciting current,the flow rate of inside molten pool is increase.