H13钢低温离子氮化组织与性能的研究

Study on the microstructure and properties of low temperature ion nitriding (LTPN) H13 steel

采用空心阴极辅助离子渗氮设备对H13模具钢分别进行了纯氮气以及氮氢混合气的低温离子渗氮，用金相显微镜（OM）、X射线衍射仪（XRD）、扫描电子显微镜（SEM）及3D形貌仪，对样品组织与形貌进行表征，用显微硬度计、CSM纳米压痕仪、洛氏硬度计及球盘式摩擦磨损仪，对样品的机械性能进行表征．研究结果表明：氢气在渗氮过程中起到很好的还原作用且能增加表面的活性点密度，渗氮后样品表面抵抗塑性变形的能力增强并优于反应气体为纯氮气的．在10N载荷下渗氮钢的磨损形式主要为粘着磨损与氧化磨损，同时伴随着轻微的磨粒磨损，低温渗氮后模具钢的耐磨性提升了12～14倍．

A new type of hollow cathode auxiliary nitriding equipment was used to do low temperature ion nitriding in our present work. The H13 steel were treated in the different atmosphere, i.e. pure nitrogen and mixed nitrogen and hydrogen gas. Optical microscope, X-ray diffraction（XRD）, scanning electron microscopy （SEM）,3 d profilometer were used to characterize the constituent phases and microstructure. Microhardness tester, Rockwell apparatus, CSM Nanoindentor, ball on disk friction-abrasion testing machine were used to characterize the mechanical properties. The resutlts show that hydrogen can be effective to increase the surface active point density in the process of nitriding because of its reducibility. After nitriding, the surface resistance to plastic deformation ability is enhanced, and the surface resistance to plastic deformation ability of the compound layer is better than that without compound layer. Under 10N loading, the wear mechanism of the nitrided steel is mainly adhesive wear and oxidation wear, accompanied by a slight abrasivewear. The wear resistance of the die steel has been improved by 12-14 times after low temperature nitriding.