Improvement in frictional and fatigue performances of AISI 4150H steel by dual ultrasonic nanocrystal surface modification for ball screw applications

Abstract The importance of a newly developed dual UNSM (ultrasonic nanocrystal surface modification) technology on rolling friction (RF) and rotary bending fatigue (RBF) of a ball screw made of AISI 4150H steel was investigated. RF tests against AISI 52100 steel were performed under grease-lubricated conditions. The results revealed that the RF and RBF were improved after dual UNSM technology, where an improvement in surface integrity and an introduction of compressive residual stress played an influential role, respectively. Based on these results, it can be assured to achieve a smooth motion, a low noise, small torque fluctuations and an extended service life of ball screws.