Forming Technology for Cold Forging Processes of Ball Stud Using Non-Heat-Treated Cold Forging Materials
A microalloyed (MA) forging steel is non-heat-treated materials that have been replacing for conventional quenched and tempered (Q/T) structural steels since the MA forging steels are very cost-effective compared with Q/T steels for the production of automotive parts. However, due to a high strength and low elongation, it has been difficult to apply the MA cold forging steel to the ball stud for automobile. In this study, finite element analyses were carried out to investigate the forming loads, the stress and strain distributions of the workpiece in the cold forging processes of the ball stud using the MA cold forging steel. Compression test at room temperature and fatigue test were also performed to obtain the flow stress and fatigue life, respectively. From these results, it was found that the fatigue life was greatly affected by the strength in the neck region of the ball stud and the cold forging processes should be designed to improve the fatigue life of the ball stud used the MA cold forging steel.
Z.Y. Zhong, H. Saka, T.H. Kim, E.A. Holm, Y.F. Han and X.S. Xie
G. A. Lee et al., "Forming Technology for Cold Forging Processes of Ball Stud Using Non-Heat-Treated Cold Forging Materials", Materials Science Forum, Vols. 475-479, pp. 3247-3250, 2005