Formable Hot-Rolled Steel with Increased Strength
Abstract:
HOT-ROLLED STEELS WITH GOOD FORMABILITY are normally available up to the 550 MPa (80 ksi) yield strength level. For higher strength the quenched and tempered steels are predominant. At Svenskt Stal AB, Domnarvet a new hot-rolled formable strip steel with increased strength has been developed, DOMEX 640 XP. The minimum yield strength is 640 MPa (92 ksi) and the steel is commercially available in thicknesses 3 to 8 mm. The steel can be classified as a carbon manganese steel microalloyed with 0.035%niobium and 0.14% vanadium. The high strength is achieved through controlled processing in a wide hot strip mill. Despite the high yield strength the steel shows very good bending properties as a result of (1) low carbon content (2) small amounts of non-metallic inclusions and (3) sulfide-shape control (calcium-treated). The formability has also been characterized by drawability and stretchability tests together with forming-limit diagram curves. The new steel can be welded easily with all conventional methods. Properties as impact toughness, fatigue strength and dent resistance have also been tested and are discussed. Typical applications are in areas where low weight is of importance e.g. mobile cranes and earth-moving rquipments.
Author:
T. Nilsson
Affiiation
Svenskt StaI Aktiebolag, Domnarvet, Borlange, Sweden.
PDF:
Source:
Vanadium Structural Steels - Reprint of papers on vanadium steel from the proceedings of “ASM HSLA Steels Technology and Applications Conference, Philadelphia, USA, Oct., 1983, pp.133-120
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