电阻点焊电磁力的试验分析

由于电阻点焊使用的是高电流,因此在焊接过程中产生强磁场.文中以固定式点焊机为例,将电极臂及电极等效为一段通电导体,对电阻点焊过程中产生的电磁力作了理论分析,研究了电阻点焊电磁力的测试方法,并在一台中频直流焊机上对电磁力进行了测试.理论分析和试验结果均表明,电磁力的作用是使得电极力减小,即电磁力有抵消电极力的作用;电磁力的大小主要与焊接电流及电极臂的开口高度有关,与焊接电流的平方成正比,与电极臂的开口高度成反比.因此,在实际焊接中,在设定或测试电极力时,应充分考虑电磁力的影响.

Analysis on electromagnetic force in resistance spot welding

In resistance spot welding,a strong magnetic field is generated due to a high current applied.A theoretical analysis on electromagnetic force caused in the process of resistance spot welding was carried out based on stationary machines by simplifying the electrode arms and electrodes as electric conductors,and the electromagnetic force was measured by means of a middle-frequency DC machine.The results indicate that the electromagnetic force has an effect on reduction of the electrode force,i.e. counteracting the electrode force.The electromagnetic force is mainly affected by the welding current and electrode-arm open depth.It is direct proportional to the square of the welding current and inverse proportional to the electrode-arm open depth.Therefore,the effect of electromagnetic force must be considered when the electrode force is set or measured in the real production.