10Ni5CrMoV钢厚板MIG焊接接头组织研究

Structure of 10Ni5CrMoV steel MIG welding joint

用光学显微镜和电子显微镜对 10Ni5CrMoV船用钢厚板的MIG焊接接头进行了组织分析和断口分析 ;用能谱分析仪 (EDS)对焊缝及熔合线处的氧化物作了定点谱成分析 ,根据组织分析和氧化物成分分析结果对针状铁素体的形成及韧化机理进行了探讨 .研究结果表明 :焊缝组织为针状铁素体 +氧化物 +少量板条马氏体 ,熔合线附近组织为板条马氏体 +针状铁素体 +氧化物 ,粗晶区组织为板条马氏体 ;焊缝及熔合线附近的氧化物是针状铁素体的形核剂 ,针状铁素体可以在一个氧化物上实现多维形核 .

Structure of 10Ni5CrMoV steel MIG welding joint was studied with OM, TEM and SEM. The element of oxides in weld metal and fusion line was measured with EDS. The mechanism of nucleation of the acicular ferrite and that of toughening of the acicular ferrite was discussed. The results showed: the structure in weld metal is acicular ferrite+oxides+lath martensite; the structure in fusion line is lath martensite+acicular ferrite+oxides; the structure in coarse-grained HAZ is lath martensite; the oxides are the particles that cause nucleation of acicular ferrite to occur and a lot of acicular ferrite in weld metal and fusion line should be one of the important reasons for an excellent low temperature toughness of weld metal and fusion line.