渗扩时间比对AISI 316不锈钢渗氮层组织与性能的影响  

Effect of nitriding and diffusion time ratio on microstructure and properties of nitrided layer on AISI 316 stainless steel

作　　者：沈统 杨丽[1] 李振 冯凌宵 Shen Tong;Yang Li;Li Zhen;Feng Lingxiao(School of Equipment Engineering,Shenyang University of Technology,Shenyang Liaoning 110000,China)

机构地区：[1]沈阳理工大学装备工程学院,辽宁沈阳110000

出　　处：《金属热处理》2022年第5期183-188,共6页Heat Treatment of Metals

基　　金：辽宁省高等学校创新人才支持计划(LR2019060)。

摘　　要：采用真空两段渗氮工艺,在不同的强渗、扩散时间下对AISI 316不锈钢进行渗氮处理,通过X射线衍射(XRD)、扫描电镜(SEM)、光学显微镜(OM)、显微硬度测试和摩擦磨损试验等分析了渗氮层的组织和性能。结果表明,经过12 h的真空渗氮后,AISI 316不锈钢表面形成了一层由γ′-Fe_(4)N、ε-Fe_(2-3)N和CrN等相组成的渗氮层,其表面硬度和耐磨性能相较于基体均有明显的提高。其中,渗扩时间比为1∶1(强渗6 h、扩散6 h)时的渗层厚度约为96μm,表面硬度约为1069 HV0.5,是基体表面硬度的4.5倍,在20 N载荷下的磨损量约为基体的1/3;渗扩时间比为1∶2(强渗4 h、扩散8 h)时的渗层厚度约为120μm,ε-Fe_(2-3)N相衍射峰增强,在20 N载荷下的磨损量约为基体的1/30。延长扩散时间能增加渗氮层厚度,改善表面形貌,进一步提高不锈钢的耐磨性。AISI 316 stainless steel was nitrided by two-stage vacuum nitriding process under different strong nitriding and diffusion time. The microstructure and properties of the nitrided layers were analyzed by means of X-ray diffraction(XRD), scanning electron microscope(SEM), optical microscope(OM), microhardness test and friction and wear test. The results show that after vacuum nitriding for 12 h, the nitrided layer consisting of γ′-Fe_(4)N, ε-Fe_(2-3)N and CrN phases is formed on the surface of AISI 316 stainless steel. The surface hardness and wear resistance of the nitrided AISI 316 stainless steel are significantly improved compared with those of substrate. Among them, when the nitriding and diffusion time ratio is 1∶1(strong nitriding for 6 h and diffusion for 6 h), the thickness of the nitrided layer is about 96 μm, the surface hardness is about 1069 HV0.5, which is 4.5 times of the surface hardness of the substrate, and the wear loss under the load of 20 N is about 1/3 of that of the substrate. When the nitriding and diffusion time ratio is 1∶2(strong nitriding for 4 h and diffusion for 8 h), the nitrided layer thickness is about 120 μm, the diffraction peak of ε-Fe_(2-3)N phase is enhanced, and the wear loss under the load of 20 N is about 1/30 of that of the substrate. The prolonging of diffusion time can increase the thickness of nitrided layer, improve the surface morphology, and further improve the wear resistance of the AISI 316 stainless steel.

关 键 词：真空渗氮 AISI 316不锈钢 渗扩时间比 显微组织 耐磨性能 

分 类 号：TG156.8[金属学及工艺—热处理]