An experimental and numerical study of heat transfer coefficient in deformation zone during hot rolling of aluminum alloy

Of the total heat lost by aluminum strip during the hot rolling process, three quarters or more can be lost to rolls. Accurate characterization of the roll-gap heat transfer coefficients (HTC) is the most important for precise prediction of the strip temperature during hot rolling. A series of pilot mill hot rolling tests have been performed. These rolling experiments encompassed a range of rolling pressures, rolling speeds, reductions and temperatures. In these tests, the temperatures of specimens and the rolling pressure were recorded during rolling using a data acquisition system. The numerical simulation was used to study the heat transfer and temperature distribution of the strip during hot rolling. The corresponding heat transfer coefficients in the roll bite were back-calculated by a trial-and-error method using this model. The results show that the HTC is linearly related to roll pressure, but it is not strongly dependent on the other rolling parameters. An approximate linear computation formula is also provided.