高耐磨药芯焊丝堆焊组织及基体选择

Microstructure of hardfacing metal and matrix materials with high abrasive flux-cored wire

制备了高铬铸铁型自保护药芯焊丝,并采用此焊丝分别在Y-Ni4铸铁、65Mn钢、40Cr钢和灰口铸铁基体上进行堆焊.对不同堆焊试样进行硬度测试,对堆焊金属及其结合部位进行显微组织及断口形貌观察.结果表明,堆焊金属硬度在60HRC以上,断裂方式均为解理断裂.65Mn钢堆焊试样熔合较好,且基本无裂纹,可在受冲击载荷较大的条件下使用;Y-Ni4铸铁堆焊试样熔合良好,但在热影响区存在裂纹,应在冲击载荷较小或不受冲击载荷条件下使用;40Cr和灰铸铁堆焊试样熔合不好,熔合区存在许多缺陷,不宜作为耐磨堆焊基体材料.

Four matrix materials,Y-Ni4 cast iron,65Mn steel,40Cr steel and grey cast iron,were hardfaced by the high chromium cast iron of self-shielded flux-cored wire separately.The hardness of different hardfacing specimens was measured,and the microstructures,fracture morphologies and the binding sites of different hardfacing specimens were observed.The results show that the hardness of the hardfacing metal is over 60 HRC and the fracture is of cleavage type.The fusion zones of 65Mn and Y-Ni4 hardfacing metal are good ones.However,the cracks can be observed in the heat-affected zone of Y-Ni4 hardfacing specimen.Therefore,the hardfacing metal of 65Mn steel is suitable for the condition of high stress wear and Y-Ni4 cast iron is suitable for the lower one.Besides,there are many defects in the fusion zone of 40Cr and grey cast iron hardfacing specimens,which are not suitable for the wear resistant matrix materials.