High Strength Steel Sheets for Automobile Suspension and Chassis Use--High Strength Hot-Rolled Steel Sheets with Excellent Press Formability and Durability for Critical Safety Parts

摘要

JFE Steel has developed two new high strength hot-rolled steel sheets which provide excellent performance in automobile suspension and chassis parts: (1) "NANO-HITEN," a new precipitation-hardened high strength hot-rolled steel sheet in which precipitates are refined to a size of several nanometers, giving the material an excellent balance of elongation and the hole-expansion ratio, and (2) "BHT steel sheet (bake-hardenable steel with tensile strength increase)," a new strain-aging type high strength hot-rolled steel sheet which features low strength and high formability during forming and a large increase in tensile strength after paint baking, resulting in a higher fatigue limit and improved crash-worthiness. This paper describes the features and properties of these new products.