Abstract
An accurate evaluation of transient heat transfer coefficients during quenching is quite important to estimate the thermal shock resistance of ceramics, especially for the quenching medium which makes phase change. In this paper, transient heat transfer coefficients for typical quenching media are obtained from experiments and calculations, and then Biot's numbers are estimated under various quench conditions. Thermal shock stresses in specimens during quench tests are also analyzed numerically by a finite element method. Results show that Biot's numbers vary with the initial temperature of the specimen and the variations of thermal stress with time in the case of cooling by boiling heat transfer differ from those of cooling by convection heat transfer. It is also mentioned that thermal shock stresses do not always increase in spite of the increase in the quenching temperature difference under the heat transfer of the transition boiling and the film boiling regions.
