Characteristics of the surface heat transfer coefficient for Al ₂O ₃ ceramic in water quench

In this paper, we determined the surface heat transfer coefficient of Al ₂O ₃ ceramics quenched from different initial temperatures into a water bath at room temperature. By using the multipoint temperature measurement technique and the inverse heat conduction method, this coefficient was measured as function of surface temperature of the ceramics during the water quench. The obtained results indicate that the surface heat transfer coefficient largely depends not only on the initial quenching temperature and their evolution in quenching media but also on the sizes of tested specimens. In addition, brief discussion was completed on the rationality of the traditionally used approach, which considers the surface heat transfer coefficient as a joint constant of materials and quenching media, in previous studies on heat transfer and thermal stresses.