Effects of some variations in composition on mechanical properties of controlled-rolled and normalized vanadium steel 12mm plates

Abstract

In this paper the results are given of tensile and Charpy V-notch impact tests on 12 mm plates from a series of vanadium and vanadium-niobium steels made from laboratory melts, in which the effects of variations in carbon, manganese, vanadium, nitrogen, and aluminium, with and without niobium, have been studied. Properties from plates in the controlled-rolled condition and after normalizing are reported. Each of the elements, except aluminium, raised the yield strength, and their effect on the major parameters governing yield strength has been examined by using the Hall-Petch analysis. Grain refinement provided the greatest strengthening in most of the steels but the largest variation in strength was due to precipitation strengthening in the normalized steels, whereas retained substructure probably made a considerable contribution to strengthening in the controlled-rolled steels. Improvements in yield strengths were not always accompanied by a loss in toughness; in some steels additions of vanadium, with nitrogen and niobium, tended to increase the yield strength and lower the transition temperature in the controlled-rolled condition.