Short‐term heat treatment of the high‐alloy cold‐work tool steel X153CrMoV12: Calculation of metastable microstructural states

The influence of short-time heat treatment on the widely used and commercially available ledeburitic cold-work tool steel 1.2379 (X153CrMoV12; AISI D2) is examined herein. Starting from a soft annealed initial condition, the influence of different austenitizing temperatures and holding times on the metastable microstructural states after heat treatment/hardening is investigated. The experimental implementation of the heat treatment is used in a quenching dilatometer, and a microstructural simulation model is built using these results. As validation of the model, on the one hand, the martensite start temperature (M-s) is used, measured experimentally by dilatometry. Additionally, the carbide content and distribution, as determined by quantitative image analysis, are compared with the simulated data and used as an indicator of the model accuracy. Through the developed simulation model, arbitrary heat treatment-induced metastable microstructural states can be calculated. As a possible application of this model, the live-adaption of the industrial heat treatment process in dependence on the batch chemical composition is discussed.