Research and Development of Microalloyed Medium Carbon Steels

The hardness of microalloyed medium carbon steels is affected significantly by chemical compositions and the conditions in hot forging. Authors investigated first the effect of chemical compositions on the strength of medium carbon steels and introduced “Hardness Equivalent Parameter”, H_eq. By this parameter, it becomes possible to design the steels for automobile components with various strength. Then authors examined the effect of hot working conditions on the mechanical properties of the microalloyed steels and obtained the proper processing conditions for them. After the research programs authors carried out the running test of engine and suspension components built in a passenger car and certified that the microalloyed steels possess satisfactory properties as forged.