电阻焊填补匙孔技术机理

Essence of the technology of filling keyhole based on resistance welding

电阻焊填补匙孔技术(FKBRW)是最近提出的一种基于电阻焊原理的搅拌摩擦焊匙孔填补技术,不但可以实现去除匙孔的目的,对接头承载能力也有着积极的作用.为了深入研究FKBRW机理,以三相次级整流电阻点焊机为试验设备,2024-T4铝合金1.5 mm+1.5 mm的搅拌摩擦点焊匙孔为填补对象,搭建了填补压力动态行为监测平台,研究了塞棒与匙孔壁的冶金结合形式及塞棒压入匙孔过程的动态行为.结果表明,塞棒与匙孔壁冶金结合有熔化连接和固相连接两种形式,熔化连接区在接头中部,固相连接区在接头上部和下部;FKBRW技术机理是塞棒在填补压力及电阻热的联合作用下,经历了软化-下压的反复过程,最终与匙孔壁完全结合的焊补技术.

The technology of filling keyhole based on resistance welding(FKBRW)is a new filling technology for friction stir welding(FSW)keyhole,which can not only achieve the purpose of removing the keyhole but also has a positive effect on the load bearing capacity of the FSW joint.For studying the mechanism of FKBRW,the keyholes of 2024-T4 aluminum alloy friction stir spot welding of 1.5 mm+1.5 mm were filled on a three-phase secondary rectification resistance spot welding machine for test equipment,and a device monitoring the filling force dynamic behavior was built up.The results showed that there exits two boding forms between the plug and wall of keyhole.The melting connection zone is in the middle of the joints,and the solid phase connection zone is on the both upper and bottom of the joints.The FKBRW technology is a kind of composite welding process that the filling force from upper electrode presses the plug into the keyhole,and the plug goes through the process of softening and pushing and metallurgical combines fully with the wall of keyhole in the last time.