Production and Heat Treatment of Fully Dense Pressed and Sintered PM Tool Steels

Abstract

The key steps of a PM technique for manufacturing fully dense near net shape tool steel parts are described. The main production steps are powder preparation, compaction, and sintering. The pre- alloyed powders used in the process are annealed to soften them, making compacting to fairly high green densities possible. Sintering to full density is accomplished at a closely controlled temperature near the solidus of the material. The heat treatment response of sintered high-speed steel parts is similar to that of conventionally produced steels. A model for the calculation of the necessary carbon content to achieve full hardness during the heat treatment of high-speed steels was developed. The model is based on predicting the amount and approximate chemical composition of the carbides present after quenching from the austenitizing temperature and the subsequent calculation of the carbon tied up within the carbides. PM/0207