Plate products have flat shape, large width thickness ratio, and large surface area per unit volume (10 pieces). This shape feature brings the characteristics of its use: (1) large surface area, so it has a strong capacity to contain and cover, and is widely used in chemical industry, containers, buildings, metal products, metal structures and other aspects; (2) It can be cut, bent, stamped, welded and made into various product components, which is flexible and convenient to use, and plays an extremely important role in automobile, aviation, shipbuilding, tractor manufacturing and other sectors; (3) Structural members such as section steel, steel pipe, large I-beam and channel steel that can be bent and welded into various complex sections are called "universal steel". Production characteristics (1) The plate is rolled by flat roll, so it is easy to change the product specification, adjust and operate conveniently, and realize comprehensive computer control and automatic production easily. (2) The shape of the plate is simple, it can be produced in coils, and its consumption is the largest in the national economy, so it must and can achieve high-speed continuous rolling production. (3) Due to the large width thickness ratio and surface area, the rolling pressure in production is large, which can reach millions to tens of millions of Newton. Therefore, the rolling equipment is complex and huge, and the control of product width, thickness dimension accuracy, shape and surface quality becomes very difficult and complex.