Microstructures and fatigue behaviors of 25CrNi2MoV steel under electropulsing-assisted ultrasonic surface rolling

In this paper, the surface modification of 25CrNi2MoV steel was carried out by using electropulsing-assisted ultrasonic surface rolling (EUSR) process. Nano-gradient structures were prepared on the surface and subsurface of the material. The surface roughness was remarkably reduced. The surface hardness, the surface residual compressive stress and the fatigue resistance of the shaft steel are improved by EUSR treatment. The effect of EUSR treatment on the surface properties and fatigue properties of 25CrNi2MoV steel was systematically studied. The fatigue crack growth mechanism of the specimens after EUSR treatment was mainly discussed. It was concluded that the depth of the hardened and residual stress layers was significantly increased by the EUSR treatment. The fatigue life of the specimens was obviously increased by EUSR treatment. The misorientation of adjacent grains is an important indicator that affects fatigue crack growth.

Automated summary

This paper investigates the effect of electropulsing-assisted ultrasonic surface rolling (EUSR) on 25CrNi2MoV steel. The EUSR process results in the formation of nano-gradient structures, reduction in surface roughness and improvement in surface hardness, residual compressive stress, and fatigue resistance. Furthermore, EUSR treatment significantly increases the depth of hardened and residual stress layers, prolongs the fatigue life of the specimens, and identifies the misorientation of adjacent grains as an important indicator affecting fatigue crack growth.