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采用X射线衍射、扫描电镜及显微硬度等技术,综合比较和分析了H13模具钢在不同热处理状态下经相同气体渗氮处理后表层的组织结构和硬度。结果表明,经淬火+二次回火和淬火+三次回火的试样渗氮后,渗氮层厚度均达到约0.24 mm,致密化合物层厚度达到10μm以上,表面硬度HV达到950(约为HRC 67)。这两种热处理状态下渗层中化合物层均由ε相(Fe2N)、γ′相和Fe3O4构成,扩散层均由-αFe相、ε相(Fe3N)、CrN相和γ′相构成,但各相含量有差别。而淬火态和淬火+一次回火态的渗氮试样未能获得具有足够好综合性能的渗层组织。
Using X-ray diffraction, scanning electron microscopy and microhardness techniques, the surface structure and hardness of the H13 die steel were compared and analyzed after the same gas nitriding under different heat treatment conditions. The results show that the nitrided layer has a thickness of about 0.24 mm, the thickness of the dense compound layer reaches more than 10 μm and the surface hardness HV reaches 950 (about HRC 67) after nitriding by quenching + secondary tempering and quenching + tertiary tempering. ). In both of these heat treatment conditions, the compound layers in the diffusion layer are composed of ε phase (Fe2N), γ ’phase and Fe3O4, and the diffusion layers are composed of -αFe phase, ε phase (Fe3N), CrN phase and γ’ phase, Phase content is different. However, the nitrided samples quenched and quenched + once tempered failed to obtain the infiltrated tissue with sufficiently good overall properties.