【摘要】 针对H13模具钢失效而产生的磨损以及腐蚀等表面问题,采用镍基碳化硅粉末,对H13模具钢的修复层进行参数优化.为了探究激光熔覆中激光参数对修复层的影响,采用不同的激光电流、离焦量为优化工艺参数进行激光熔覆试验,发现改变激光电流、离焦量的大小对修复层的熔覆尺寸、微观组织以及力学性能均有不同程度影响;熔覆层的几何稀释率随着激光电流的增大而增大,熔覆层的晶粒尺寸变粗;熔覆层的几何稀释率随着离焦量的增大而减小,熔覆层的晶粒尺寸变细.通过金相显微镜、SEM和显微硬度仪分析得到优化结果为:激光电流115 A、离焦量51 mm,熔覆层显微硬度值达到最高,约为基材硬度的2.6倍.上述研究成果为提高模具失效表面激光熔覆修复层质量提供理论和技术依据.更多还原

【Abstract】 In view of surface problems such as wear and corrosion caused by the failure of H13 die steel, nickelbased silicon carbide powder was used to optimize the parameters of the repair layer of H13 die steel. In order to explore the effect of laser parameters on the repair layer in laser cladding, laser cladding experiments were carried out using different laser currents and defocus amounts as optimized process parameters. It was found that changing the size of the laser current and the amount of defocusing had different degrees of influence on the cladding size, microstructure and mechanical properties of the repair layer. The geometric dilution rate of the cladding layer increases as the laser current increases, and the grain size of the cladding layer becomes coarse; The geometric dilution rate of the cladding layer decreases as the amount of defocus increases, and the grain size of the cladding layer becomes finer. The optimized results obtained through the analysis of metallographic microscope,SEM and micro hardness tester showed that the laser current is 115A, the defocus amount is 51 mm, and the microhardness value of the cladding layer reaches the highest value, which is about 2.6 times the hardness of the substrate. The above research results provide theoretical and technical basis for improving the quality of the laser cladding repair layer on the failure surface of the mold.更多还原