Effect of quench probe material and section size on cooling severity

Abstract

In the present work simulation of heat transfer during quenching was carried out using finite difference heat transfer based SolidCast software. Simulation experiments were aimed to assess the effect of boundary heat transfer coefficient, quench probe material and its size on the cooling curve of the quench probe at geometric centre. Simulation results show that all these parameters had a significant effect on the simulated cooling curve of the probe. For a material, there is a critical diameter above which increase in cooling rate at the centre of the probe is negligible and this critical diameter depends on the thermal conductivity of the material used for quenching. A quenching system with a D/h ratio value of greater 0.000075m3K/W has no significant effect on the cooling rate at the centre of the probe. A simple quantitative model which correlates average cooling rate, probe material, section size and cooling severity of quench media was proposed. The results of the model is independent of characteristics of quench probe used in assessment of cooling severity and could be used effectively for selection of quenchants during heat treatment. Copyright � 2012 ASM International� All rights reserved.