Quenching Optimization and Microstructure–Hardness Analysis of 20CrMo Sliders

To determine appropriate quenching parameters for the Z45 slider, finite element simulation was combined with experimental characterization. A thermal–structural coupled model and an L9(33) orthogonal array were used to examine the effects of quenching temperature, holding time and cooling intensity on residual stress at the raceway corner. The results show that the optimal scheme is 850 °C with a holding time of 2400 s under medium cooling intensity, yielding the lowest residual stress. Based on this scheme, the slider was carburized, quenched and tempered, and its microstructure and properties were analyzed by optical microscopy, electron backscatter diffraction (EBSD) and hardness testing. The microstructure transformed from ferrite–pearlite to tempered martensite with small amounts of bainite and retained austenite. EBSD results show that the original deformation texture was clearly weakened with a marked decrease in texture intensity. Surface hardness reached 63 HRC (808 ± 19 HV), with an effective hardened case depth of 1.21 mm. These results demonstrate that the simulation-optimized quenching process produces surface microstructure and hardness meeting service requirements, providing a combined simulation–experiment reference for heat treatment optimization of 20CrMo sliders.