Ultrasonic rolling of 42CrMo Steel: Simulation-Based process optimization for high-efficiency and sustainable...

Ultrasonic rolling has emerged as a highly promising surface strengthening technique due to its ability to enhance surface properties under low energy consumption conditions. In this study, a thermo-mechanically coupled simulation model was developed to investigate the ultrasonic rolling process of 42CrMo steel, aiming to achieve a balance between high surface performance and low carbon emissions through process optimization. An orthogonal array of 25 simulation experiments were designed and conducted to analyze the effects of process parameters-including workpiece rotational speed, static pressure, feed rate, and ultrasonic amplitude-on surface properties and thermal behavior. Based on the simulation data, a response surface methodology (RSM) was employed to establish predictive models for surface performance. To address the conflicting objectives among various surface performance indicators and significantly improve both surface quality and processing efficiency, a novel hybrid optimization algorithm, the Particle Swarm Simulated Annealing Optimization (PSSAO), was proposed. Multi-objective optimization was performed to determine an optimal parameter domain that enables effective strengthening in a single-pass rolling process. The optimal processing window obtained from PSSAO was experimentally validated, and the results confirmed the reliability of the simulation model and the feasibility of this sustainable manufacturing strategy. The findings demonstrate that ultrasonic rolling of 42CrMo steel, when optimized through thermo-mechanical simulations and advanced parameter design, can effectively enhance surface properties, reduce energy consumption, shorten processing time, and lower carbon emissions-providing a viable pathway toward sustainable manufacturing. The PSSAO algorithm identified the optimal processing parameter ranges as a feed rate of 0.05-0.07 mm/r, static pressure of 520-700 N, ultrasonic amplitude of 7-9 μm, and spindle speed of 50-180 r/min. Under these conditions, the maximum residual compressive stress reaches -1283 to -1296 MPa, average surface roughness (Ra) is reduced to 0.120-0.156 μm, and surface hardness increases to 60.9-61.6 HRC.