Alloy thin steel plates are less than 4 mm thick (minimum 0.2 mm), thick steel plates are 4-60 mm thick, and extra-thick steel plates are 60-115 mm thick. Thin steel plates have a width of 500-1500 mm; thick steel plates have a width of 600-3000 mm. The types of steel used in thick steel plates are largely the same as those used in thin steel plates. In terms of product categories, besides pure thick steel plates such as bridge steel plates, boiler steel plates, automobile manufacturing steel plates, pressure vessel steel plates, and multi-layer high-pressure vessel steel plates, some steel plates, such as automobile beam steel plates (2.5-10 mm thick), patterned steel plates (2.5-8 mm thick), stainless steel plates, and heat-resistant steel plates, also overlap with thin steel plates. 2. Steel plates are divided into hot-rolled steel plates and cold-rolled steel plates.