炭素鋼のオーステナイト温度域における変形抵抗に及ぼす炭素量の影響

抄録

Deformation resistance of carbon steels with carbon content from 0.05 to 0.80wt% is examined in the austenite temperature range and at the strain rates ranging from 10^-3 to 200/s with special respect to its dependence of carbon content. Hot deformation resistance during work hardnening stage increases with increasing carbon content at lower temperature of austenite range and at higher strain rate. On the contrary, it decreases with increasing carbon content at higher temperature range and at lower strain rate. In early work hardening stage, work hardening is promoted with increase of carbon content. Work hardening rate decreases with increase of carbon content at all conditions of strain, strain rate and temperature. Such phenomena are discussed with respect to the dependence of the stacking fault energy on carbon content. The deformation resistance in second deformation stage after interruption of deformation comes close to the deformation resistance without interruption of deformation as strain increases. The precise mathematical model of resistance is obtained by a quadratic formula of regression with strain, strain rate, temperature and carbon content.