表面形变处理对32Cr3MoVA钢渗氮层组织和性能的影响

测定了32Cr3MoVA钢渗氮层的硬度分布、渗层深度和表面的相组成，对比了表面层形变后渗氮和表面未形变直接渗氮试样的组织和力学性能。结果表明，表面层形变后再渗氮可使渗氮层深度从0．34mm增加到0．61mm，表面层的显微硬度从730HV增加到840HV；X射线衍射分析表明，表面层形变后渗氮层表面的组织主要为体积分数72．6％的Fe3N和27．4％的Fe4N，而表面未形变直接渗氮试样的表面组织为体积分数为17．4％的Fe3N和82．6％的Fe24N10。

Influence of Surface Straining on Microstructure and Mechanical Property of 32Cr3MoV Steel

The hardness gradient or hardness distribution and phas es in the surface layer of the nitrided 32Cr3MoV steel were determ ined. By comparing microstructure and mechanical property of nitrided specimens with that of surface strained following nitrided specimens, it is found that the depth and microhardness of the nitrided layer increase by surface straining. T he depth of nitrided layer increases from 0.34mm to 0.61mm and the surface hard ness increases from HV730 to HV840 for the specimens after shot peening followi ng nitriding. X-ray diffraction technique was employed to determine the phases of the nitrided layer. The experimental results show that the microstructures of the nitrided layer consist of 72.6% Fe 3N and 27.4% Fe 4N in volume,for surface strained following nitrided specimen and,17.4% Fe 3N and 82.6% Fe 24N 10 in volume for nitrided specimen,respectively.