2019 Volume 27 Issue 1 Pages 17-23
In steel manufacturing processes such as hot strip, a hot-steel at a temperature higher than the Leidenfrost temperature is quenched with water to improve mechanical properties. The quenching process is governed by transient transition boiling, which includes inherently complicated intermittent wetting coupled with transient heat conduction in the hot workpiece. Existing experimental studies on quenching generally applied an exact solution of heat conduction problem during sudden contact of semi-infinite liquid and solid to assess very earlier liquid-solid interface temperature and whether the hot surface is able to be wetted or not. The prediction of liquid-solid interface at a very early stage before the inception of homogeneous or boiling nucleation is governed by the pure transient heat conduction between the liquid and solid. However, a thin porous oxide layer with poor thermal conductivity deposited on the surface may have a major effect on the earlier heat transfer. Recent progress in research on thermal properties of oxide layers enables more accurate assessment of the interface temperature characteristics. In this study, we attempted to derive an exact solution of liquid-solid interface temperature on the oxidized surface. Besides, the effects of oxide layer thickness as well as the interfacial thermal resistance between layer and base metal have been evaluated analytically.
