Analysis of temperature and microstructure in the quenching of steel cylinders

A finite-element procedure has been developed for temperature and microstru ctural analyses of quenching problems involving nonisothermal phase transfo rmations. The finite-element analysis incorporates temperature-dependent ma terial properties, time-temperature-transformation (TTT) diagrams to descri be the microstructural evolution in steels, and the latent heat released du ring a phase change. The procedure is applied to calculate temperature, mic rostructure, and hardness distributions in 1080 steel cylinders quenched in water and in two polymeric quenchants. The calculated values for the three quantities are found to be in good agreement with corresponding measuremen ts made in quenched 1080 steel cylinders, The effect of latent heat release d during a phase change on the temperature and microstructural evolution is studied computationally. It is found that, when the latent heat is not inc luded in the calculations, the resulting volume fractions of pearlite and m artensite present in the quenched steel are nearly one order of magnitude d ifferent from the corresponding values calculated by including the latent h eat in the formulation. Finally, the quenching of a large-diameter 1080 ste el cylinder in water is analyzed to show the nonlinear effect of cylinder d iameter on the temperatures and microstructures.