Study on the enhancement of surface integrity and wear resistance of iron-based coatings by ultrasonic surface rolling process

This study explores the fabrication of iron-based coatings on 45CrNiMoVA steel using laser cladding technology. Laser cladding offers advantages such as a low dilution rate and a dense microstructure but is hindered by drawbacks like poor surface finish and residual tensile stress. To address these limitations, ultrasonic surface rolling processing (USRP) was applied with varying cycles (0, 1, 3, 5) to enhance the coating's properties. Results show that USRP promotes the transformation of the FCC phase to the BCC phase on the coating surface. As the number of USRP cycles increases, the depth of the fine-grained zone, the proportion of low-angle grain boundaries (LAGBs), and the presence of deformed grains all increase progressively. The application of USRP significantly impacts the surface integrity and mechanical properties of the coating. The USRP3 coating achieved the lowest surface roughness (0.506 μm) and the highest residual compressive stress (−1140.08 MPa). Under the combined effects of reduced surface roughness, grain refinement, dislocation strengthening, work hardening, and residual compressive stress, the USRP3 coating demonstrated superior corrosion resistance and wear performance.