A New Generation of Surface-Treated Car Body Steel with Improved Tensile Strength and High Stretch Forming Ability 1999-01-3199

High-tensile steel grades are being used to an increasing extent in the construction of car bodies with a minimum weight. A special importance must be placed on a particularly high stretch forming ability, since stretch forming is that forming strain to which car body closures are most frequently exposed. In an effort to meet those requirements ThyssenKrupp Stahl AG (TKS) has developed a new generation of steel grades with moderately enhanced yield strengths of up to 350 MPa and tensile strengths of up to 450 MPa. These new grades which have an excellent stretch formability are mainly characterized by a high hardening ability which can be further enhanced by an additional bake-hardening effect. Moreover, they are excellently suited for surface treatment including hot-dip coating. The new steel grades close the gap between the high-strength IF and the multiphase steel, thus completing to the product range of high-strength grades at TKS.