Carbon steel bar is a solid long strip of steel, the common ones are round steel, square steel, hexagonal steel, octagonal steel and so on. Round steel is often used to make steel bars, bolts and various mechanical parts, as well as tube blanks for seamless steel pipes.

According to the process, round steel is divided into three types: hot-rolled round steel, forged round steel and cold-drawn round steel. According to chemical composition (that is, carbon content), it can be divided into low carbon steel round steel, medium carbon steel round steel and high carbon steel round steel. According to the quality of steel, it can be divided into ordinary carbon steel round bar and high-quality carbon steel round bar. According to the application, it can be divided into carbon structural steel and carbon tool steel.

Square steel refers to steel rolled or processed into a square cross-section, which can be divided into hot-rolled and cold-rolled.

Carbon steel classification:

1. According to the mass percentage of carbon: low carbon steel (C:≤0.25%); medium carbon steel (C:0.25≤C≤0.6%); high carbon steel (C:>0.6%)

2. According to the quality of steel (mainly the content of impurities sulfur and phosphorus):

Ordinary carbon steel (S≤0.055%, P≤0.045%)

High-quality carbon steel (S≤0.040%, P≤0.040%)

High quality carbon steel (S≤0.030%, P≤0.035%)

3. By use

Carbon structural steel: mainly used for bridges, ships, building components, machine parts, etc.;

Carbon tool steel: mainly used for tools, molds, measuring tools, etc.;