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为研究失效的6542高速钢挤压模具的修复工艺,利用5 kW光纤激光器,以预置粉末的方式在其表面熔覆Fe基合金粉末。利用光学显微镜和X射线衍射仪器研究了熔覆层的组织和物相;用摩擦磨损试验机测试熔覆层的耐磨性。结果表明:熔覆层与基体冶金结合良好,内部无气孔、裂纹;凝固组织变成平面晶后呈树枝晶生长;相比于基体,熔覆层的耐磨性有较大提高,这与熔覆层中存在的Fe-Cr、Fe_3Ni_2等细小树枝晶有关。
In order to study the repairing process of the failed 6542 high speed steel extrusion die, 5kW fiber laser was used to pretreat the Fe-based alloy powder on its surface. The microstructure and phase of the coating were studied by optical microscope and X-ray diffraction. The wear resistance of the coating was tested by friction and wear tester. The results show that the cladding layer has a good metallurgical bond with the matrix without internal pores and cracks. The solidified structure turns into a dendrite and grows dendrites. Compared with the matrix, the wear resistance of the cladding increases greatly. The presence of Fe-Cr, Fe3Ni2 and other fine dendrites in the coating are related.