Types of steel used in construction carbon structural steel

Types of steel used in construction

China's construction steel mainly consists of carbon structural steel and low alloy high strength structural steel. High-quality carbon structural steel is also used in cold-drawn carbon steel wires and fasteners for connection. In addition, thickness directional performance steel plates, weathering steel for welded structures, cast steel, etc., are also used in some cases.

Carbon structural steel

According to the national standard "carbon Structural steel" (GB/T700) production of steel Q195, 0215, 0235, Q255 and Q275 a total of 5 brands, sheet thickness is not more than 16mm, plasticity, toughness are good. This grade of steel is divided into A, B, C, D and 4 quality grades according to the different chemical composition and impact toughness, from A to D in alphabetical order, indicating that the quality grade is from low to high. In addition to grade A, the carbon content of the other three grades is below 0.20%, and the welding performance is also very good. Therefore, the steel with the Q235 grade is selected as the steel for load-bearing structure. The chemical composition and deoxidation method of Q235 steel, tensile and impact tests and cold bending test results shall comply with the provisions of Tables 2.1, 2.2 and 2.3.

"F" stands for boiling steel, "b" stands for semi-killed steel, and the symbols "Z" and "TZ" stand for killed and special killed steel, respectively. "Z" and "TZ" can be omitted when specified. For example, Q235B stands for Class B killed steel with a yield point of 235N/mm2.

In the design of cold-formed thin-wall steel structure, if the stiffness condition rather than the strength condition is controlled, it is also allowed to use Q215 steel.