Properties of thermomechanically rolled Nb/Ti microalloyed steel sheets

Structure and mechanical properties of a Nb/Ti microalloyed steel, thermomechanically rolled on a strip‐production facility, are evaluated. Small (0.02%) titanium addition to niobium‐containing steel is found to increase precipitation while reducing grain‐refining potential of niobium. This effect increases with increasing finish‐rolling temperature, and is also reflected in an increased charpy energy transition temperature. A reduced tendency for precipitation in a nitrogen‐free austenite together with the short interpass times in the finishing train, is assumed to reduce the tendency for pancaking, which is prerequisite for an effective grain refining.