Stabilization and destabilization of austenite in Cr−Ni−Co−Mo maraging steel

1. For the Cr−Ni−Co−Mo steels investigated the character of the martensitic transformation changes with decreasing MS (induced by slight changes in chemical composition) — the isothermal transformation is superposed on the athermal transformation. 2. The rate of the isothermal transformation increases with decreasing MS and evidently for this reason the susceptibility of austenite to thermal stabilization increases in the process of cooling and during repeated heating after quenching. 3. For steels with>15% retained austenite after the original quenching the cooling conditions after austenitizing must be strictly controlled (cooling with compressed air, for example), since the amount of retained austenite may be affected by stabilization and destabilization processes and also stresses that occur in the process of cooling during quenching. 4. Steels of the transition class investigated cannot be heated in the temperature range of 200–500° (welding, cutting, et al.) before the cold treatment.