Ausforging, in which quenching is performed direct from the high finishing temperature of forging, is one of the energy saving heat treatments. A disadvantage is that it results in degradation of impact toughness especially in low-alloy steels of relatively high Mn content.
Ti treatment, which consists of controlling the amounts of Ti and N addition, solidifying in continuous casting process, and breaking down the blooms at appropriate temperatures, was found to improve the impact toughness of ausforged and tempered specimens through both preventing grain growth at forging temperatures and accommodating grain boundary segregation.
Ti treatment was also applied to vanadium-containing steel subjected to air-quenching (air-cooling from the finishing temperature of forging), and a higher level of impact toughness was successfully achieved by air-quenching.
