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选用42CrMo钢为实验材料,分别进行普通离子渗氮处理、活性屏离子渗氮处理及预氧化+离子渗氮处理。利用金相显微镜观察离子渗氮层的显微组织;利用XRD分析离子渗氮层中的各种物相;在试验结果的基础上,分析不同的离子渗氮方式及不同的渗氮工艺参数对渗层组织和性能的影响。结果表明:42CrMo钢经离子渗氮处理后由表及里形成明显的白亮层和扩散层;渗层由Fe2-3N和Fe4N组成;离子渗氮后试样的表面硬度得到明显提高;在不同的离子渗氮方式下,渗氮工艺参数对化合物层厚度及扩散层厚度的影响规律存在一定的差异。活性屏对离子渗氮起到一定的促进作用,低温时尤为显著。离子渗氮前进行预氧化处理,可以加速渗氮过程的进行,其中在300℃下预氧化30 min效果最佳。
42CrMo steel was selected as the experimental material, respectively, ordinary ion nitriding, active screen ion nitriding and pre-oxidation + ion nitriding. The microstructure of the ion nitriding layer was observed with a metallographic microscope. The phases in the ion nitriding layer were analyzed by XRD. Based on the experimental results, the different ion nitriding methods and different nitriding process parameters were analyzed Penetration layer organization and performance. The results show that: 42CrMo steel by ion nitriding from the table and the formation of a clear white layer and diffusion layer; diffusion layer composed of Fe2-3N and Fe4N; ion nitriding sample surface hardness was significantly improved; in different Ion nitriding mode, nitriding process parameters on the thickness of the compound layer and diffusion layer thickness of the law there are some differences. Active screen on the ion nitriding play a role in promoting, especially at low temperatures. Pre-oxidation of ions before nitriding can accelerate the process of nitriding, in which the pre-oxidation at 300 ℃ for 30 min is the best.