Middle board is a flat steel with a large width-to-thickness ratio and a large surface area. The materials are Q235, Q345, 20#, 16MN, 304, 316 and other specifications. In actual work, steel plates with a thickness of <=25 mm are often referred to as medium plates. The middle board have great coverage and tolerance and can be used as houses. Panels, cover materials and manufacturing containers, oil storage tanks, packing boxes, train boxes, automobile shells, industrial furnace shells, etc.; can be cut and combined according to the requirements of use to make various structural parts and mechanical parts. It can be made into welded steel to further expand the use range of steel plate; it can be bent and stamped to make boilers, containers, punched car shells, civil utensils, appliances, and can also be used as blanks for welded steel pipes and cold-formed steel.