Cu基钎料MIG钎焊接头断裂行为分析

Fracture Behavior Analysis of MIG-brazed Joint with Cu-based Filler Metals

研究用Cu3Si1Mn钎料、Cu10Mn6Ni钎料分别MIG钎焊镀锌Q2 35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Si是以Fe2 Si相形式存在 ,而Mn是以固溶体形式存在 ;用Cu3Si1Mn、Cu10Mn6Ni钎料钎焊镀锌Q2 35钢板接头抗拉强度试样均断在母材 ,抗拉强度为 30 8.2～ 30 8.7MPa ,钎焊 1Cr18Ni9Ti不锈钢板 ,拉伸均断在钎缝 ,其抗拉强度分别是 331.5MPa、42 3 .6MPa ;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(Cu10Mn6Ni钎料 ) 。

MIG brazing for joining galvanized Q235 steel sheets and 1Cr18Ni9Ti stainless steel with Cu3Si1Mn and Cu10Mn6Ni brazing filler metal is investigated.The experiment results indicate the Si and Mn rich band is produced at the interface between filler metal and base metal.XRD analysis shows that Si existed as Fe 2Si and Mn in the form of solid solution.Tensile testing specimens using Cu3Si1Mn and Cu10Mn6Ni as filler metal fractured at the base metal galvanized Q235 steel sheets with the joint strength of 308.2 MPa to 308.7 MPa.The joint specimens of stainless steel 1Cr18Ni9Ti fractured in the brazed seam with the strength of 331.5 MPa and 423.6 MPa.Tensile fracture analysis shows that the fracture area was originated at the bottom of lap brazing seam,which was 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(Cu10Mn6Ni filler metal),which was ductile fracture.