40Cr钢磨削淬硬层组织形成机理的研究

以单程切入式平面磨削淬硬加工试验为基础，利用X射线衍射仪和透射电镜对40Cr钢磨削淬硬层组织的形成及其变化进行了研究，进而阐明了磨削淬硬层组织的形成机理。结果表明，40Cr钢磨削淬硬层由板条马氏体和少量微细孪晶组成；在磨削温度场和应力．应变场的耦合作用下，磨削淬硬层中的马氏体含量以及板条马氏体特征尺寸沿层深呈现不同的变化趋势，马氏体内部的位错密度及孪晶数则随层深的增加而逐渐降低。

Study on forming mechanism of microstructure on the grind-hardened layer of 40Cr steel

On the basis of the one-pass plunge surface grinding-hardening test, the microstructure and its variations of the grind-hardened layer of 40Cr Steel were studied by using the X-ray diffractometer and TEM, which further explaining the forming mechanism of microstructure of the grind-hardened layer. The result shows that the microstructure of hardened layer consists of the lath martensite and a few fine micro-twins. Under the coupling actions of the grinding temperature field and stress-strain field, the martensite content and characteristic size of the lath martensite of the hardened layer have a tendency to different changes along the depth direction. The dislocation density and the amount of twin inside the martensite gradually decreases with the increasing of the depth in the hardened layer.