热处理对SLM H13钢组织和摩擦磨损性能的影响

Effects of heat treatment on microstructure and friction wear performance of SLM H13 steel

系统探讨了热处理对选区激光熔化(selective laser melting,SLM)技术制备的H13工具钢的微观组织和摩擦磨损性能的影响。基于780℃和830℃2种热处理温度,通过改变热处理条件来研究其对SLM-H13钢微观结构和摩擦磨损性能的影响。试验采用电子背散射衍射(EBSD)、显微硬度测试及摩擦磨损试验等方法进行材料表征。研究发现,热处理显著改变了材料的微观组织,780℃和830℃热处理的样品展示了不同的组织演变,组织变化导致磨损性能也有所不同。在室温下,未经热处理的SLM-H13钢表现出细小的细胞状网格和柱状晶体结构,这些特征是SLM工艺快速凝固过程的典型结果,同时显示出最优的摩擦磨损性能,具有较低的摩擦系数和磨损率,其磨损机制主要为磨粒磨损。对经过780℃和830℃热处理的样品进行了系统分析,结果表明热处理显著改变了SLH-H13钢的微观结构,主要表现为熔池边界逐渐消失、晶粒出现粗化、晶界开始均匀重组,此外,残余奥氏体和马氏体的晶体取向也发生了演变,这些微观结构的变化对摩擦磨损性能有直接影响,表现为780℃和830℃的磨损率都较打印态样品的磨损率出现了增加,其磨损机制为磨粒磨损与疲劳磨损,随着热处理温度升高还表现出氧化磨损的特征。研究表明,适当的热处理可以调整SLM-H13钢的微观结构,但对其磨损性能的提升作用有限,这一发现对于SLM H13钢在苛刻工况下的应用提供了重要的微观机制理解和指导。

The impact of heat treatment on the microstructure and tribological performance of H13 tool steel fabricated via selective laser melting(SLM)technology is systematically investigated.Research was conducted focusing on two heat treatment temperatures,780℃and 830℃,to study their effects on the microstructure and tribological properties of SLM-H13 steel.Material characterization was conducted using Electron Backscatter Diffraction(EBSD),microhardness testing,and friction wear tests.The findings indicate that heat treatment significantly alters the material's microstructure,with samples treated at 780℃and 830℃displaying different structural evolutions,leading to varied wear performances.At room temperature,untreated SLM-H13 steel exhibits fine cellular grids and columnar crystal structures,typical of the rapid solidification process in SLM,and shows superior tribological performance with a lower coefficient of friction and wear rate,primarily through abrasive wear mechanisms.Systematic analysis of samples treated at 780℃and 830℃revealed that heat treatment markedly changes the microstructure of SLM-H13 steel,primarily evident as the gradual disappearance of melt pool boundaries,grain coarsening,and uniform reorganization of grain boundaries.Additionally,there was a transformation in the crystal orientations of residual austenite and martensite.These microstructural changes directly impact the tribological performance,manifested by increased wear rates at 780℃and 830℃compared to the untreated samples,with wear mechanisms including abrasive and fatigue wear,and characteristics of oxidative wear becoming apparent with increased treatment tem-perature.While appropriate heat treatment can modify the microstructure of SLM-H13 steel,its effect on enhancing wear performance is limited,providing critical insights into the micro-mechanisms for the application of SLM H13steel under harsh operating conditions.