Development of Cold-stamped Door Impact Beams Made of 1180 MPa Grade High Strength Steel Sheet

Abstract

Cold-stamped door impact beams made of TS1180 MPa grade cold-rolled high strength steel have been developed. The newly developed parts achieved both weight and cost reductions compared to former hot-stamped parts. Cold-stamping was successfully performed by using a newly developed high strength steel sheet with high ductility. To avoid delayed fracture, conditions (applied stress, strain and hydrogen) in which hydrogen cracking of the steel occur were drawn up on a map and then applied conditions of the parts were set accordingly at safe levels far from the hydrogen cracking regions indicated on the map.