原始组织对40Cr钢磨削硬化层的影响研究

Effect of Original Structure on the Grind-Hardened Layer of 40Cr Steel

在平面磨床上 ,采用刚玉砂轮和干磨削方式对 4 0Cr钢进行了表面磨削硬化处理 ,研究了原始组织对磨削硬化层组织与性能的影响。结果表明 ,在磨削温度和应力的综合作用下 ,完全硬化区马氏体均呈现“细 -粗 -细”的变化规律 ,且相对粗大马氏体相出现在次表层 ,而过渡区组织的形成因原始组织而异。此外 ,原始组织对完全硬化区显微硬度无显著影响 ,硬度值均在 6 30～ 70 0HV之间 ,原始组织越均匀 。

The surface grind-hardening of 40Cr steel was carried out with alumina grinding wheel and dry grinding method. The effect of original structure on the microstructures and properties of grind-hardened layer was studied. The results show that the martensite microstructure of the hardened layer varies from fine to coarse and then backs to fine in the completely hardened zone, due to the combined action of temperature and stress during grinding. The coarse martensite formed in the subsurface of the hardened layer. Microstructure of the transition zone varies with original structure. Furthermore, the micro hardness in the completed hardened zone is 630～700HV in different original structure. With increasing of the uniformity of original structure, the depth of hardened layer and completely hardened zone increases.