Steel is one of the four major varieties of steel (type, line, plate, tube), is a widely used steel. According to the cross-section shape, the section steel is divided into simple section steel and complex or special section steel (special-shaped steel). The former is characterized by crossing any point on the periphery of its cross-sectional tangents generally do not pay in the section. Such as: square steel, round steel, flat steel, angle steel, hexagonal steel, etc .; common profiled steel with hot-rolled window frame steel, plowshare steel, hot-rolled steel wheel ring with steel, track plate with hot-rolled steel, car wheel rim Hot-rolled steel, rail, shipbuilding ball flat steel, cable tray steel, scraper steel and so on.

Shaped steel because of its uniqueness and unity of use, often more accurate than the simple profile section of the steel, which has a higher capacity of the equipment requirements. Because of its complex cross-sectional shape, especially for many special-shaped special-shaped steel occasions, even with little experience to learn, making the hole design and production more difficult than the simple profile section steel. Therefore, the production cost of shaped steel is higher than the simple section steel. Shaped steel because of the size of their large differences, many of which are specific to an industry or specific occasions, so a single species of the market demand is often not large. Therefore, the scale of special-shaped steel production system is often not very big.