Ordinary carbon steel is also known as ordinary carbon structural steel, also known as ordinary carbon steel. The carbon content is 0.06-0.22%, and less than 0.25% is commonly used. Belonging to low carbon steel, each metal grade represents the low yield point of the steel when the thickness is less than 16mm. Compared with high-quality carbon steel, there are wider restrictions on carbon content, property range and content of phosphorus, sulfur and other residual elements. According to the guarantee conditions of delivery, my country and some countries divide ordinary carbon steel into three categories: Class A steel (Class A steel), which only guarantees mechanical properties and does not guarantee chemical composition, Class B steel (Class B steel), Only the chemical composition is guaranteed, but the mechanical properties are not guaranteed; the special steel (C-type steel) guarantees both the chemical composition and the mechanical properties. Special steel is often used to manufacture more important structural parts.

Element:

It is mainly used to make carbon structural steel for engineering structural parts. It is generally used in the state of supply, and the content of sulfur and phosphorus in steel is relatively high, which are allowed to reach 0.050% and 0.045% respectively. This type of steel accounts for a large proportion of the total production of steel.

Application:

This type of steel can be smelted by oxygen converter, open hearth or electric furnace, and is generally hot rolled into sheets, strips, profiles and bars. Steel sheets are generally delivered in hot rolled (including controlled rolling) or normalized state. The chemical composition, tensile properties, impact energy and cold bending properties of the steel shall comply with relevant regulations.

In the Chinese national standard GB700-88, this kind of steel is divided into 5 grades according to the yield point value, and is divided into 4 grades according to the quality. Its grade is composed of four parts in sequence, including the letter Q representing the yield point, the yield point value, the quality grade symbol, and the deoxidation method symbol.

This type of steel has a wide range of applications, most of which are used as welded, riveted or bolted structural steel parts, and a few are used to make various machine parts. The lower strength Q195 and Q215 steels are used to make low carbon steel wires, steel wire meshes, roof panels, welded steel pipes, anchor bolts and rivets. Q235 steel is moderately strong, has good ductility and toughness, and is easy to form and weld. This kind of steel is mostly used as steel bars and steel structural parts, and also used as rivets, railway spikes and various mechanical parts, such as bolts, tie rods, connecting rods, etc. High-strength Q255 and Q275 steels are used to make various agricultural machinery, and can also be used as steel bars and railway fishplates.

According to the special performance requirements of some industrial steels, the composition of ordinary carbon structural steel is slightly adjusted to form a series of professional steels, such as riveting screw steel, bridge steel, pressure vessel steel, hull steel, boiler steel. In addition to strictly controlling chemical composition and ensuring conventional performance, professional steels also stipulate some special inspection items, such as low temperature impact toughness, aging sensitivity, gas in steel, inclusions and fractures.