Search Results

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.

The quality of a final product in particular made from hot-rolled sheet metal, is dependent upon the initial blanking, applied prior to forming the part. The material thickness and strength are the most important factors influencing the shearing parameters to be chosen. High-strength grades offer certain specific advantages when combined to consolidated blanks. Those type of tailored blanks requires a special practice and knowledge to shear the material independent of the grade and thickness used. The shearing in particular, guillotine shearing of various materials and thicknesses were studied in order to carry out a high quality cut for laser-beam welding purposes. In addition, the stamping of those materials, with special regard to high-strength and mild steel grades mostly used to stamp complex parts for automotive applications, are discussed as well.