Development of a Formable Low Carbon Columbium Bearing High Strength Hot Rolled Sheet Steel

The purpose of this paper is to show the approach used by automotive and line pipe steel producers to develop a higher strength sheet steel with improved formability, toughness, and welding characteristics. Also covered are the appropriate stages of steelmaking and hot rolling leading to the development of a columbium-bearing steel with a minimum yield strength of 50 ksi. Typical mechanical properties and forming capabilities are presented, together with a discussion of the strengthening mechanisms and ductility factors utilized to achieve this formable 50 ksi product.