短路过渡CO_2焊接短路历程分析与控制

在剖析短路历程对短路过渡CO2焊接的焊接过程稳定性、焊接工艺性能和焊接质量影响的基础上,首先对短路历程不同阶段熔滴液桥的受力分析可知,短路初期较大的焊接电流将阻碍熔滴在熔池中的顺利铺展,而短路中后期的脉冲大电流将强化电磁力对液桥缩颈的形成;进而在依据短路期间电源输出回路电阻变化曲线对短路进程进行判断的基础上,采用在短路初期施加小电流、在中后期施加脉冲大电流、在缩颈破断前降低焊接电流的短路电流控制方法,对短路历程的控制进行了实验研究。结果表明,短路历程的一致性得到有效控制,短路过渡CO2焊接的焊接工艺性能得到显著改善。

Analysis and Control of Short-circuit Experience in Short-circuit CO_2 Welding

The influence of short-circuit experience on the welding process stability,process behavior and welding quality in short-circuit CO_2 welding was anatomized.After that,the analysis of mechanics on the liquid bridge of molten droplet during the different phase of short-circuit was carried out,which shows the results that a larger current at the prophase will block the molten droplet to well spread into the molten pool,but a large pulse current at the metaphase will strengthen the function of electromagnetic force on the formation of liquid bridge neck.Furthermore,the experimental research on the control of short-circuit experience was accomplished,in which the short-circuit course was judged according to the welding loop resistance curve during short-circuit period,and then a smaller welding current was adopted at the prophase,a large pulse current was added to the metaphase and the current was decreased again just before the rupture of liquid bridge neck.The experimental results show that the accordance of short-circuit experience is controlled effectively and the process behavior of short-circuit CO_2 welding is improved evidently.