细丝大电流MAG焊的熔滴过渡机制

Mechanics of drop transfer for high-current density MAG welding process

借助高速摄像分析了两种常规混合气体(80%Ar+20%CO2和98%Ar+2%O2)保护的细丝大电流MAG焊的基本特点,研究了焊丝伸出长度和保护气体成分对第二临界电流的影响规律,揭示了细丝大电流MAG焊的熔滴过渡机制.同时详细地分析了离心破断过渡、混合过渡和旋转短路过渡的产生条件和形成过程.并指出了80%Ar+20%CO2气体保护的细丝大电流MAG焊之所以无法应用的根本所在,从而确立了98%Ar+2%O2气体保护的细丝大电流MAG焊实现高效化焊接的可行性.

With the help of high-speed camera,the fundamental character of high current density MAG welding process with two types of conventional shielded gas is analyzed.The influence of wire extension and shielded gas component on the second critical current is researched.So the mechanics of drop transfer of high-current density MAG welding process is disclosed,which is centrifugally breaking transfer,mixed transfer and rotating short transfer.Moreover,the reason of why high-current density MAG welding process with the shielded gas of 80%Ar and 20% CO2 cannot be used is found.The application practicability of high effective welding for high-current density MAG welding process with the shielded gas of 98%Ar and 2% O2 is built.