镁合金的活性电弧焊接

在不同的电流条件下,研究了9种常见氧化物、氟化物、氯化物活性剂在镁合金交流氩弧焊及变极性等离子焊弧中的行为.结果表明:活性剂TiO2、Cr2O3、AlF3、NiCl2、CdCl2、ZnCl2、MgCl2使镁合金交流氩弧焊焊缝熔深增加;MgF2、SiO2使镁合金交流氩弧焊焊缝熔深减小;TiO2、SiO2、Cr2O3、AlF3、NiCl2、CdCl2使镁合金变极性等离子弧焊焊缝熔深增加;MgF2、ZnCl2、MgCl2使镁合金变极性等离子弧焊焊缝熔深减小;活性剂对镁合金交流氩弧焊焊缝熔深增加的作用大于对镁合金变极性等离子弧焊的;电弧收缩是活性剂使得镁合金电弧焊焊缝熔深增加的原因之一;活性剂的加入使得焊缝的晶粒比未涂敷活性剂时粗大.

Activating flux for arc welding of magnesium alloy

The behavior of nine kinds of familiar fluxes including oxide, chloride, fluoride in the AC-TIG and variable polarity plasma arc(VPPA) welding of magnesium were studied under the condition of different welding currents and arc stiffness. The results show that in the magnesium AC-TIG welding, the fluxes as TiO_2, Cr_2O_3, AlF_3, NiCl_2, CdCl_2, ZnCl_2, MgCl_2 all increase weld penetration, MgF_2, SiO_2 fluxes reduce the weld penetration, while in the VPPA welding, TiO_2, SiO_2, Cr_2O_3, AlF_3, NiCl_2, CdCl_2 fluxes increase the weld penetration, MgF_2, ZnCl_2, MgCl_2 fluxes reduce the weld penetration. However, the increase of weld penetration is not obvious for VPPA welding comparing with AC-TIG welding. Besides, the contraction of the arc is one of the reasons increasing the weld penetration, and the crystal grain size of the weld with flux is bigger than that without flux.