TIG焊接过程中熔池对流形式的示踪分析
Tracer investigation of convection in weld pool under TIG welding process
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摘要: 为验证传统钨极惰性气体保护焊接过程和双层气流保护焊接过程的熔池表面对流形式,确定双层气流保护焊接方法的熔池深度增加机理,试验研究以钨颗粒为示踪相,焊前将300~500μm的钨颗粒均匀涂覆于焊件表面,同时在熔池底部两侧插入钨板,将焊接熔池中心区域和边缘区域阻隔开.传统钨极惰性气体保护焊接方法在熔池表面产生外向对流,钨颗粒随对流集中于熔池边缘;双层气流保护焊接方法在熔池表面产生内向对流,钨颗粒随内对流集中于熔池中心.结果表明,示踪试验确定了熔池流动方向,为活性组元改变熔池表面对流方向提供了试验验证.Abstract: Tungsten particles were chosen as the trace-element to investigate the pattern of the Marangoni convection on the pool surfaces of conventional TIG and double shielded TIG weld and to study the mechanism of the TIG weld shape variation. Before welding, the 300-500 micron size tungsten particles were uniformly smeared on the surface of work piece which were inserted two tungsten plates at the pool bottom to separate the weld pool center area and the edge region. For conventional TIG welding process, outward Marangoni flow existed on the pool surface and the tungsten particles concentrated in the two edges at the pool bottom. For double shielded TIG process, an inward Marangoni convection on the molten pool surface and tungsten particles located on the pool center between the two tungsten plates. Tracer test proved the flow direction of the weld pool in the TIG process and verified the active element could change the direction of the Marangnon convection.
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Keywords:
- TIG welding /
- tracer test /
- Marangoni convection /
- tungsten particles
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