Cu基钎料电弧钎焊接头强度及断口分析

研究用钨极氩弧焊作为热源，用Cu3Si1Mn钎料、56Cu8Mn26Zn钎料分别钎焊A3钢板及1Cr18Ni9Ti不锈钢板。试验结果表明，在钎料/母材界面分别存在Si、Mn富集带，经XRD分析表明，Si是以Fe2Si相形式存在，而Mn是以固溶体形式存在；用Cu3Si1Mn、56Cu8Mn26Zn钎料钎焊A3钢板接头抗拉强度试样均断在母材，抗拉强度为308.2～308.7MPa，钎焊1Cr18Ni9Ti不锈钢板，拉伸均断在钎缝，其抗拉强度分别是331.5 MPa、382.9 MPa；拉伸断口分析发现，断裂起裂点在搭接钎缝的根部，主要是母材成分与少量的钎料成分混合、溶解而成，是脆性断口；止裂点在钎缝金属中（Cu3Si1Mn钎料）或在近界面上（Cu3Si1Mn钎料），是塑性断口。

JOINT STRENGTH AND FRACTURE ANALYSIS OF ARC BRAZING WITH Cu BASED FILLER METALS

TIG brazing for joining A3 steel sheets and 1Cr18Ni9Ti stainless steel with Cu3Si1Mn and 56Cu8Mn26Zn brazing filler metal is investigated. The experiment results indicate the Si and Mn rich band is produced at the interface of filler metal and base metal. XRD analysis shows that Si existed as Fe2Si and Mn in the form of solid solution. Tensile testing specimens using Cu3Si1Mn and 56Cu8Mn 26Zn as filler metal fractured at the base metal with the joint strength of 308.2 MPa to 308.7 MPa. The joint specimens of stainless steel 1Cr18Ni9Ti fractured in the brazing seam with the strength of 331.5 MPa and 382.9 MPa. Tensile fracture analysis shows that the fracture area is originated at the bottom of lap brazing seam, which is brittle fracture composed of the components of base metal and filler metal, and ended in the brazing seam(Cu3Si1Mn filler metal) or at the vicinity of interface(Cu3Si1Mn filler metal), which is ductile fracture.