Abstract
We have beeen investigating the nitrogen penetration mechanism of high carbon chromium bearing steel JIS-SUJ2 (SAE52100 equivalent) in the carbonitriding process. Our previous research results exhibited that partial H2 pressures and residual NH3, and carbon activity in an ambient furnace atmosphere were the rate-detemining factors of nitrogen penetration. In this study, an atmospheric imbalance of partial NH3 pressure was experimentally analyzed. In addition, distribution map of the partial NH3 pressure was calculated by CFD analysis in which the decomposition reaction rate was take into account. The extrapolated data obtained from CFD analysis corresponds well with the experimental data. Hence, we believe that the CFD analysis is effective in order to control carbonitriding quality and to devise heat treatment furnace structures.
