自保护药芯焊丝立向下焊接熔滴过渡观察与分析

Observation and Analysis of Metal Transfer of Self-shielded Flux Cored Wire for Vertical Down Welding Condition

采用高速摄像方法对自保护药芯焊丝的熔滴过渡进行了观察分析发现,自保护药芯焊丝立向下焊接时的熔滴过渡模式为短路过渡、弧桥并存过渡、爆炸过渡和颗粒过渡,弧桥并存过渡是其主要过渡形态.弧桥并存过渡形态包含弧桥并存爆炸过渡和弧桥并存表面张力过渡,前者的主要特征是桥的爆炸,后者则是液相桥和熔池接触,熔滴金属通过表面张力的作用进入熔池.随着电流增加,熔滴尺寸减小,过渡频率增大,弧桥并存过渡和爆炸过渡增加,短路过渡减少.

Metal transfer of self-shielded flux cored for vertical down welding condition is studied by using high speed photographic method. The results show that the modes of metal transfer are short circuit transfer, bridging transfer without arc interruption, explosive transfer, and globular transfer. Bridging transfer without arc interruption is the main mode and it also contains two kinds of modes, explosive transfer and surface tension transfer. The characteristic of the former is the explosion of the bridge and the later is that the molten droplet, contacting with molten pool, transferring into the pool by the action of surface tension. As the welding current grows, the droplet becomes small, the frequencies of metal transfer increases, the amount of bridging transfer without arc interruption and explosive transfer increases, and the amount of short circuit transfer decreases.