表面形变处理对32Cr3MoVA钢渗氮层组织和性能的影响

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

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 .6 1mm ,表面层的显微硬度从 730HV增加到 84 0HV ;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 2 7.4 %的Fe4 N ,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Fe2 4 N1 0 。

The hardness gradient or hardness distribution and phases in the surface layer of the nitrided 32Cr3MoV steel were determined. 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. The depth of nitrided layer increases from 0.34 mm to 0.61 mm and the surface hardness increases from HV730 to HV840 for the specimens after shot peening following 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% Fe3N and 27.4% Fe4N in volume, for surface strained following nitrided specimen and, 17.4% Fe3N and 82.6% Fe24N10 in volume for nitrided specimen, respectively.