Hot-rolling mills are generally divided into the following zones:furnace area(for heat supply prior to deformation),rolling area,and finishing area.Rolling stocks will be homogeneously preheated to defined temperature by socking pits in the furnace area.THe rolling area completes the rolling process.Rolling trains are normally adapted to the products to be rolled.Hence,there are very many many defferent types of train,such as roughing trains,intermediate and finishing trains.