High Strength Formable Steels for Automobile Applications

Interstitial free steel sheets are extensively being used for making outer and inner automobile body panels due to their excellent drawability and stretchability. Conven-tional grades of steels such as titanium/niobium/titanium-niobium stabilized generally possess high formability and low strength being suitable only for inner body panels, whereas outer body panels require high strength high formable steel sheets. The strength of IF steel can be increased through solid solution hardening as well as precipitation hardening elements. So far the steel stren-gthened by solid solution hardening element phosplhorus was considered the most promising, attaining strength upto 350-400 MPa and r-value around 1.8.