Effect of Gradient Microstructure on Wear Properties of 23CrNi3Mo Steel

The sliding wear performance of 23CrNi3Mo steel is intimately correlated with a surface gradient microstructure. This study utilized ultrasonic surface rolling processing (USRP) to generate the gradient microstructure on the material surface through severe plastic deformation. The results of the study show that the lath martensitic refinement, the average grain size is refined to 2.671 μm, with a weakened initial <111> grain orientation and a significantly escalated proportion of <101> oriented grains. The maximum pole density reached 4.2, accompanied by an increased fraction of small‐angle grain boundaries and a kernel average misorientation value of 0.8172°. After 25 USRP passes, the surface residual compressive stress and Vickers microhardness (HV0.5) of the sample reached 1583 MPa and 831 HV0.5, respectively. The wear test results demonstrate that the coefficient of friction is reduced by 10.2% (from 0.59 to 0.50), while the wear rate decreases by an order of magnitude to 7.62 × 10 −7 mm −3 /(N m). The improved wear resistance primarily stems from the synergistic contributions of grain refinement strengthening, dislocation hardening, and strain‐induced work hardening. The gradient microstructure not only enhances the surface integrity but also optimizes tribological performance through multi‐scale microstructural regulation.