激光功率对27SiMn钢熔覆层组织与性能的影响

为了探寻激光功率对熔覆层组织与性能的影响,设计4种不同激光功率在27SiMn钢表面进行Fe-Cr-Ni熔覆层制备,利用超景深显微仪、显微硬度计、摩擦磨损试验机对熔覆层的显微组织、硬度、磨损量及摩擦因数进行了研究。结果表明,4种激光功率下的试件熔覆层均无气孔裂纹等缺陷,激光功率为1800 W时所制备试件的枝晶生长方向较为一致,激光功率为2400 W时所制备试件熔覆层中部的胞状晶和二次枝晶晶胞较为细小致密;随着激光功率增加,熔覆层的熔宽、熔深和稀释率逐渐增大,而熔高则先增大后减小;熔覆层硬度受激光功率影响较小,但增大激光功率可以提高热影响区硬度;激光功率为2400 W时所制备试件的平均摩擦因数最小、磨损量最少、磨损深度最小,其耐磨性能优良。

Effect of laser power on microstructure and properties of clad layer on 27SiMn steel

In order to explore the influence of laser power on microstructure and properties of the clad layer, four different laser powers were designed to perform Fe-Cr-Ni clad layer preparation on the surface of 27SiMn steel. The microstructure, hardness, wear loss, and friction coefficient of the clad layers were studied by means of super depth of field microscope, microhardness tester and friction and wear tester. The results show that the clad layer of the specimens under four different laser powers has no defect such as pore and crack, and the dendrite growth directions of the specimen prepared under the laser power of 1800 W are relatively consistent. The cellular crystal and the secondary dendrite in the middle part of the clad layer prepared under the laser power of 2400 W are smaller and denser. As the laser power increases, the melting width, melting depth and dilution rate of the clad layer gradually increase, while the melting height first increases and then decreases. The laser power has little effect on hardness of the clad layer, but the increase of laser power can raise the hardness of the heat affected zone. The specimen prepared under the laser power of 2400 W has the minimum average friction coefficient, the least wear loss, the minimum wear depth, and its wear resistance is excellent.