采用钛钙型药皮堆焊焊条D172,以手工电弧焊工艺在45钢上堆焊一定厚度的堆焊层,仅堆焊1层时,得到的堆焊金属厚度约3 mm,堆焊3层后,堆焊层厚度可达到8 mm左右;通过显微组织观察、硬度测试和能谱分析等对不同堆焊条件下的热影响区和过渡区的组织和硬度、熔合区附近碳的迁移过程进行了分析.结果表明:随焊接线能量增大,熔合区奥氏体组织减少,铁素体组织增多;熔合区附近基体侧铁素体和珠光体组织变得细小,堆焊层侧马氏体组织变得粗大,其硬度值降低;堆焊3层时,熔合区附近堆焊层侧碳化物明显析出、聚集,马氏体组织较粗大.

Bead welding process was conducted by shielded metal arc welding process on 45 steel substrate using electrode D172.When single layer metal was deposited on the substrate,the thickness of deposited metals is about 3 mm,and the 3rd deposited metal was put on the pre-deposited metals,the total thickness of deposited metals is about 8 mm.The microstructure was observed,and the hardness and ES analysis were made.The microstructure and hardness of heat-affected zone and transition zone in different weld conditions,and migration of carbon in the vicinity of fusion area were analyzed.The results show that the higher the heat input,the less the austenite and the more the ferrite in fusion area,the smaller the pearlite and ferrite of base material in the vicinity of fusion area,the coarser the martensite and the lower the hardness value of deposited metals in the vicinity of fusion area.If the three layer metals were deposited on the substrate,the carbides of deposited metals in the vicinity of fusion area were precipitated and gathered,and relatively coarse martensite was formed.