The Effect of Cryogenic Treatment on the Punch Wear and the Hole Edge Geometry

Abstract

The ball joint parts made of forged steel are quite important in the suspension system. The quality of production of ball joint parts is very important because of their role. Some basic defects can be found in the hole edge form. These defects affect the hole quality of ball joint parts. In this study, the effects of cryogenic processing on the wear of AISI D2 punches and the effects of punch wear on the hole edge geometry of hot forged AISI 1040 steel ball joint parts were investigated. The hole geometry changes are generally associated with punch wear and process parameters. For the purpose of investigation, piercing was carried out using an eccentric press with AISI D2 tool steel punches on 6.0 mm-thick ball joint pieces. The punches were traditionally heat treated. Some of the punches were cryogenic-treated at -145 °C in addition to the conventional heat treatment. Weight loss values were measured to assess the punch wear, and SEM and OM images were analysed. At the end of the industrial piercing process, it was found that the D2 tool steel punch wear decreased with cryogenic process applied and the size changes in the hole edge geometry of the punched 1040 hot forged steel parts turned out to be less marked.