The Effect of Hot-Mounting on the Microstructure of an As-Quenched Auto-Tempered Low-Carbon Martensitic Steel

The effect of hot-mounting for metallographic studies of as-quenched low-carbon martensitic steels has been studied. Hot-mounting is typically carried out at 150-200 degrees C, i.e., a low-temperature tempering regime. Cold- and hot-mounted specimens from an as-quenched low-carbon auto-tempered steel were examined using a scanning electron microscope and their hardness levels were also compared. It was found that hot-mounting causes additional tempering that manifests as the appearance of new precipitates in those regions that are free of auto-tempered cementite. The observations were rationalized using DICTRA simulations to calculate the potential growth of cementite. Hot-mounting was also shown to cause a small but statistically significant increase in the hardness of the martensite.