Surface temperature and heat transfer coefficient determination during quenching for martensite fraction prediction using a parabolic heat transfer model

A simplified method is presented to predict the transient temperature distributions in a cylinder during quenching. The model is based on the assumption that the radial temperature distribution follow a parabolic-type behavior. To validate the model, AISI 304 stainless steel cylindrical samples (08 mm) were instrumented with thermocouples for temperature data acquisition during quenching. The samples were heated to 900°C followed by quenching in water-base salt solutions. Based on the results of the model, in conjunction with the transformation diagrams of the alloy, it was possible to predict the martensite fraction formation in the radial direction. A practical example of the use of the predicted transient temperature distributions and martensite fraction at various radial depths is presented in this paper for a partially decarburized AISI 5160 steel.