Round steel is divided into three types: hot-rolled, forged and cold-drawn. The specifications of hot-rolled round steel are 5.5-250 mm. Among them: 5.5-25 mm small round steel is mostly supplied in bundles of straight bars, and is often used as steel bars, bolts and various mechanical parts; round steel larger than 25 mm is mainly used to manufacture mechanical parts, seamless steel pipe blanks, etc.