Development of Microalloyed Medium-Carbon Steel with Improved Toughness

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Development of Microalloyed Medium-Carbon Steel with Improved Toughness

The application of the hot-rolled microalloyed medium-carbon steel is limited due to its lower toughness compared with quenched and tempered steels. A high strength microalloyed medium-carbon steel has been developed to meet the increasing demand for eliminating heat treatment.The effects of chemical compositions, hot-deforming temperatures and cooling rates after hot-de forming on mechanical Properties of the steel were investigated. Attention was given to the steel toughness above the required value for safety components in application. The basic microstructural variables controlling the properties were discussed. It is demonstrated that toughness and machinability can be improved through the addition of 0.5% Si, 0.5% S and 0.01% Ti.Toughness can be further improved by controlling hot-deforming temperature and subsequent cooling rate.