Influence of Low-Temperature Assisted Ultrasonic Surface Rolling Process on the Friction and Wear Properties of Cr12MoV Die Steel

To address the issues of wear and surface cracking during mold service, prolong the service life of molds, and improve the processing quality and efficiency of workpieces, a low-temperature-assisted ultrasonic rolling process was employed to strengthen the surface of Cr12MoV die steel. Experimental results indicate that the surface integrity and wear resistance of Cr12MoV die steel are significantly enhanced through low-temperature-assisted ultrasonic surface rolling process treatment. This technology generates plastic deformation, smooths the material surface, reduces defects and stress concentration points, and subsequently decreases the friction coefficient and wear volume. At a feed rate of 1400mm/min, the friction coefficient reaches its minimum, and the wear volume is significantly reduced. Additionally, although the low-temperature condition does not significantly improve surface roughness compared to room-temperature ultrasonic rolling, it achieves higher residual compressive stress in the surface layer, significantly enhancing the wear resistance of the material. The samples treated with room-temperature ultrasonic rolling are more prone to adhesion by the counter ball, leading to severe surface damage and spalling, forming larger spalling pits, and a large number of abrasive particles are present at the wear scar. In contrast, the samples treated with low-temperature-assisted ultrasonic rolling exhibit less material spalling and shallower wear depth, with numerous furrows and primarily abrasive wear. This study provides new ideas and methods for presetting high residual compressive stress on mold steel surfaces and improving their wear resistance.