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等离子弧粉末堆焊,在焊道搭接处往往形成凹坑或疏松现象。这种现象,是由于电弧在衰减过程中,衰减速度太快或太慢造成的。如果衰减太快,即电弧在很短的时间内突然熄灭,等离子焰流对焊道有冲击作用,熔化的合金来不及填充焊道,形成凹坑。同时,在熔化过程中渗入的气体来不及排出,而被迫封在里面形成气孔。衰减过慢,即延时时间过长,这样不仅降低生产效率,并且由于那些未熔透的合金粉末被夹入焊层里,形成疏松,形成蜘蛛状或蜂窝状小孔。凹坑影响焊道的几何尺寸,
Plasma arc welding powder, weld lap often formed at the pit or loose phenomenon. This phenomenon is due to the arc in the attenuation process, the attenuation speed too fast or too slow. If the attenuation is too fast, that is, the arc suddenly extinguishes within a short period of time, the plasma flame has an impact on the weld bead, and the melted alloy is too late to fill the weld bead to form a dimple. At the same time, the gas infiltrated in the melting process was too late to be expelled and was forced to seal inside to form pores. Attenuation is too slow, ie, the delay time is too long, which not only reduces production efficiency but also forms loose, spider-like or honeycomb-shaped pores due to the unfinished alloy powder being trapped in the solder layer. Depression affects the weld bead geometry,