Round steel is categorized into three types: hot-rolled, forged, and cold-drawn. The specifications for hot-rolled round steel range from 5.5 to 250 millimeters. Among them: round steel with a diameter of 5.5 to 25 millimeters is usually supplied in bundles as straight bars, commonly used as reinforcement bars, bolts, and various mechanical components; round steel larger than 25 millimeters is primarily used for manufacturing mechanical parts and billets for seamless steel pipes.

By application, they can further be categorized as:Carbon structural steel、Carbon Tool Steel。

Carbon tool steel with carbon content ranging from 0.65% to 1.35%, after heat treatment, it achieves high hardness and excellent wear resistance. Primarily used in the manufacturing of various tools, cutting tools, molds, and gauges (see tool steel).

Carbon structural steel is divided into 5 grades according to the yield strength of the steel:

Q195、Q215、Q235、Q255、Q275

Each brand is divided into grades A, B, C, and D due to varying quality, with some having up to four grades while others have only one. Additionally, there are differences in deoxidation methods for steel smelting.

Material of round steel: Q195, Q235, 10#, 20#, 35#, 45#, Q215, Q235, Q345, 12Cr1Mov, 15CrMo, 304, 316, 20Cr, 40Cr, 20CrMo, 35CrMo, 42CrMo, 40CrNiMo, GCr15, 65Mn, 50Mn, 50Cr, 3Cr2W8V, 20CrMnTi, 5CrMnMo, etc.