Martensitic Steel Sheets of 1300 and 1500MPa Grades

Super-high strength steel sheets of a strength exceeding 980 MPa have been used in reinforcement parts for automotive bumpers and door to meet strengthened collision safety standards and to decrease weight for the sake of emission reduction. A study has been conducted to improve the bending workability, resistance weldability, and delayed-fracture immunity required for the steel sheets used in parts produced through cold forming, such as bumper reinforcements. The study then led to the development of martensitic steel sheets of 1300 MPa and 1500 MPa grades. The newly developed steel has enabled the production of bumpers of 1300 MPa grade and 1500 MPa grade, the world's highest grades for cold worked bumper reinforcements, while also enabling 10 to 15% less weight compared with conventional bumper reinforcements.