After normal quenching of high-speed steels, 25%-35% retained austenite(rR). If rR is not stable, it would turn into martensite. During martensitic transformation, when stress is lower than yield strength, plastic deformation will occur. This phenomenon is named martensitic transformation plasticity.
For many years, heat correction of quenched parts is believed can achieve remarkable results. Although it contains factors that will cause thermoplasticity and contribution to good rR plasticity, the most important one is phase transformation superplasticity’s effect. The superplasticity effect of phase transformation occurs in the whole process of R → M phase transition, but this effect is transient. When phase transformation is most intense, the superplasticity effect of phase transformation is the most significant, so the frequency curve of the plastic variable should demonstrate a peak value.