Mechanism research on eliminating voids in bearing steel ball by floating-pressure method (FPM)

Abstract

To eliminate internal void and improve the mechanical properties of steel balls formed by skew rolling, the floatingpressure method (FPM) using high-pressure gas to compact void is applied in this paper. By establishing void closure mechanical model, effects of various factors on void closure are obtained. The change rule of microstructures and outline of steel ball is investigated using DEFORM-3D Finite element software, and results show that when void is entirely closed, steel ball diameter decreases by less than 2 %, and its dimensional accuracy is guaranteed; the dynamic recrystallization of the metal around void promotes the healing of micro-cracks. The FPM experiments are performed, which verify the accuracy of the finite element model.

Keywords

• bearing steel ball
• skew rolling
• voids
• strain
• FPM