Search Results

Forged components to be used in high strength applications have traditionally been heat treated after forging. This processing route unfortunately suffers from many technical and economical shortcomings. The first attempt to overcome these difficulties led to the development of medium carbon microalloyed steels for bar applications in the early 1970's. While these steels did not require heat treatment, their strengths were limited. Furthermore, the notch toughness of these steels was rather poor. The limitation on strength and toughness have hindered their acceptance as a substitute for the conventional QT steels, especially in safety critical components. In addition, these shortcomings eliminate the possibility of downsizing through redesign. Since the tempered martensite and the microalloyed ferrite-pearlite steels have obvious limitations, an alternative microstructure had to be developed.