Carbon steel round bar is a solid long steel bar with a circular cross-section. Its specifications are expressed in diameter in millimeters (mm). Round bars are divided into three types: hot rolled round bars, forged round bars and cold drawn round bars according to the process section. According to the chemical composition (ie 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 steel and high-quality carbon steel round steel. According to the use, it can be divided into carbon structural steel and carbon tool steel.

1. Carbon structural steel

Carbon structural steel is generally not heat-treated, and is used directly in the supplied state. Usually Q195, Q215, Q235 steel has low carbon mass fraction, good welding performance, good plasticity and toughness, and certain strength. It is often rolled into thin plate, steel bar, welded steel pipe, etc.

Used in bridges, buildings and other structures and in the manufacture of ordinary rivets, screws, nuts and other parts. The mass fraction of carbon in Q255 and Q275 steel is slightly higher, the strength is higher, the plasticity and toughness are better, and it can be welded. It is usually rolled into section steel, bar steel and steel plate as structural parts and to manufacture connecting rods, gears and couplings of simple machinery. Sections, pins and other parts.

2. High-quality structural steel

High-quality carbon structural steel is mainly used in the manufacture of machine parts. Generally, heat treatment is required to improve the mechanical properties. Depending on the carbon mass fraction, there are different uses.

3. Carbon tool steel

Carbon tool steel is a high-carbon steel that basically does not contain alloy elements. The carbon content is in the range of 0.65%-1.35%. Its production cost is low, the source of raw materials is easy to obtain, and it has good machinability. High wear resistance, so it is widely used in the manufacture of various cutting tools, molds, measuring tools.

4. Free-cutting structural steel

Free-cutting structural steel is to add some elements that make the steel brittle to the steel, which is beneficial to increase the cutting speed and prolong the tool life. The element that makes steel brittle is mainly sulfur, and elements such as lead, tellurium, and bismuth are used in ordinary low-alloy free-cutting structural steel.