Mechanical properties and microstructure of 0·06C–2·0Mn–0·14V steel

Abstract

The mechanical properties and microstructure have been studied of an experimental 0·06C–2·0Mn–0·14V steel, controlled rolled to 13mm plate using soaking temperatures of 1000°−1300°C, finish-rolling temperatures of 660°−800°C, and rolling reductions of 63, 74, and 80%. The optimum combinations of strength and impact toughness were obtained with a soaking temperature of 1100°C. Plates reduced by 74 and 80% to finish at 660° and 750°C had yield stresses of 654−682 MN m⁻², impact transition temperatures of −30° to −78°C, and transverse shelf energies of 74−108J. Plates that were reduced by 63% to finish at 660°−800°C had yield stresses of 449−525 MN m⁻², impact transition temperatures of −140° to 15°C, and transverse shelf energies of 130−235J. Raising the soaking temperature to 1200° and 1300°C produced yield stresses of 511−658MN m⁻² but increased the impact transition temperature to −30° and 65°C. Details are given of the processing conditions that promote grain refinement, various forms of ferrite, split fracture-surfaces, and continuous stress–strain curves. The mechanical properties are explained in terms of the effect of the various processing parameters on the contributions to strength from precipitation, grain refinement, and dislocation substructure.