Comparative Analysis of Shot-Peened CrMoV Steels: Microstructural, Residual Stress, Surface Roughness, and Hardness Investigations

The study investigates the impact of shot peening on various CrMoV steels—base, annealed, and cryogenically treated—focusing on changes in microstructure, mechanical properties, and surface residual stresses. It employs various experimental methods, including annealing cycles, cryogenic treatments, shot peening procedures, microstructural analysis, surface roughness measurement, residual stress evaluation, and hardness testing. The results reveal significant effects of shot peening, such as grain refinement, surface imperfections, and increased compressive residual stresses. The effectiveness of shot peening is influenced by the treatment history, with cryogenic treatment, in contrast to traditional annealing, leading to a greater increase in compressive residual stresses. Cryogenically treated samples exhibit more pronounced hardness improvements due to better microstructure and higher dislocation density. Surface roughness analysis indicates that while shot peening increases roughness in both cryo-treated and annealed steels, it enhances the surface finish of the base material.