变形镁合金填丝TIG焊接工艺及组织性能分析

董长富; 刘黎明; 赵旭

变形镁合金填丝TIG焊接工艺及组织性能分析

Welding technology and microstructure of tungsten inert-gas welded magnesium alloy

摘要

摘要: 采用自动填丝TIG焊接工艺连接变形镁合金AZ31B板材,研究填丝TIG焊接与非填丝TIG焊接的异同点,并分析不同成分的焊丝对焊接接头的影响,探索出了合理的焊接工艺参数,分析了焊缝微观组织及拉伸断口。结果表明,与非填丝TIG焊相比,填丝TIG焊的焊接工艺更加复杂,接头强度有了较大的提高,组织更均匀。针对不同焊丝的焊接接头分析表明,随着填丝TIG焊接中焊丝含铝量的增加,热影响区及焊缝区的白色共晶相逐渐增多并有呈连续分布的趋势,同时晶粒趋于细小。该共晶体的增多对接头性能影响较为复杂,一方面由于脆性相Mg₁₇Al₁₂的增多而降低了接头强度,另一方面又因晶粒的细化以及铝元素的固溶而提高接头强度。拉伸结果显示采用AZ61焊丝的接头强度最高,断口分析表明,为混合断口。

Abstract: Tungsten inert-gas(TIG) welding was used to weld deforming magnesium alloy AZ31B.The difference between TIG welding with filler metal and without filler metal was studied.Microstmcture,tensile and fatigue strength of the weld with different filler metal were investigated.The result showed that compare with TIG welding without filler metal TIG welding with filler metal has improved tensile strength.For different filler metal,the eutectic phase will increase with increase of aluminum content in filler metal.The increasing of eutectic will reduce the joint strength because of the increasing of Mg₁₇Al₁₂,and on the other hand it will improve the strength for the solution of aluminum into α-Mg.From the study of fracture,the mixed fracture is observed.

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