The occurrence of quenching cracks in high-carbon tool steel depending on the austenitizing temperature

The aims of the research were to determine the cause of the cracks in high‑carbon tool steel and to analyze the influence of the austenitizing temperature on the occurrence and propagation of quenching cracks. The results show that the main cause of quenching cracks is a too high austenitizing temperature caused by poor temperature control. A temperature that is too high leads to excessive austenite grain growth, distinctive grain boundaries with coarser martensite and the presence of retained austenite. On the other hand, the best properties and the absence of quenching cracks occur when C85S steel is quenched from a temperature below the Acm temperature.