Hot galvanized sheet is hot rolled galvanized sheet, cold galvanized sheet is cold rolled galvanized sheet. From the material point of view, the composition of the two galvanized sheets are basically similar, the difference is that the cold galvanized sheet is thinner than the hot galvanized sheet, the surface quality is better, the process is more complex, and the price is higher. From the process point of view, the steel is rolled by hot rolling, rolled into a certain thickness of the plate, such as the thickness of 10mm or so, if the user has no higher requirements for the surface of the plate, thickness, mechanical strength, it can be processed as a finished product, such as galvanized, sold directly, is a hot plate. If there are higher requirements for the plate, then the hot-rolled plate is sent to the cold rolling line for re-processing, after pickling, annealing, re-rolling and other processes, to get a thinner, smooth surface and better mechanical properties of the cold-rolled plate.