CP780复相高强钢工频与中频电阻点焊接头性能对比分析

Comparison and Analysis of Performance of Power Frequency and Intermediate Frequency Resistance Spot Welding Joints of CP780 Steel

使用工频和中频两种不同电流波形焊机对CP780复相钢进行电阻点焊,通过调整焊接电流、焊接时间和电极压力,研究了电流波形和焊接工艺参数对接头性能的影响。结果表明:两种焊机点焊接头最大剪切力均随着焊接电流和焊接时间的增加而增加,随着焊接压力的增加而降低。在相同工艺参数下,中频焊机所获焊点尺寸大于工频焊机,焊点剪切力始终高于工频焊机;点焊接头由熔核区、热影响区和母材区构成,熔核区为粗大的板条状马氏体,中频焊机点焊接头熔核区和热影响区的硬度低于工频焊机。中频焊机的最佳焊接工艺参数为:焊接电流10 kA,焊接时间400 ms,电极压力5 kN,剪切力可达28 245 N。

Two kinds of current waveform welders with power frequency and intermediate frequency were used to carry out resistance spot welding on CP780 multiphase steel. By adjusting welding current, welding time and electrode pressure, the influence of current waveform welder and welding process parameters on joint performance was studied. The results show that the maximum shear force of spot welded joint increases with the increase of welding current and welding time, and decreases with the increase of welding pressure. Under the same process parameters, the solder joint size obtained by the intermediate frequency welder is larger than that of the power frequency welder, and the solder joint shear force is always higher than that of the power frequency welder. The spot welding joint is composed of core zone, heat affected zone and base metal zone. The core zone is a thick strip martensite. The hardness of the core zone and heat affected zone of the spot welding joint is lower than that of the industrial frequency welding machine. The optimal welding process parameters are intermediate frequency welding machine, welding current 10 kA, welding time 400 ms, electrode pressure 5 kN, shear force up to 28 245 N,which provides a reference for CP780 high-strength steel welding process parameters and welding machine selection.