Chinas structural steel number
The structural steels used in China are mainly Q235 and Q345. The Q represents the yield point. 235 refers to the value of yield strength of steel, which is 235; 346 represents the value of yield strength of steel, which is 346 MPa. Structural steels with strength values higher than 345MPa are called high-strength steels.
Q235 is carbon structural steel, which is the most commonly used in construction and engineering structures. Steel plate with a thickness of 16-40mm can be processed into various types of welding parts suchas steel beams, bridges, ships, vehicles, boilers, containers, oil pipelines, large tanks, etc. Structural parts and components used in engineering structures, such as rivets and bolts due to their strength are commonly made of Q235 materials. It can also be used for parts in railway and mechanical engineering, such as load-bearing members, rivets, bolts and nuts, etc.
Q345 is a low-alloy, high-strength structural steel. It is widely used as welding, riveting and components in engineering structures because of its good comprehensive mechanical properties. It is also used to make machine parts and containers, which require good processing performance and plasticity. Q345 can also be used to make large tanks, which are suitable for use in cold conditions.
The classification of structural steel is mainly divided into hot rolled and cold rolled steels. Hot rolled steel is formed at high temperature and the product has an irregular shape, but it is strong and durable. Cold-rolled steel is formed at low temperature and has good surface properties, but the stress value is low. Structural steel also has grades A, B, C, D and so on, and different strength grades have different requirements on steel plate thickness and impact temperature values.
Structural steel has the advantages of high ductility, toughness and weldability, but it has low corrosion resistance. In order to improve its corrosion resistance and weather resistance, structural steels are often coated with rust-proof paint and oil. In addition, the use of structural steel must be reasonable and scientific, to reduce the risk of failure caused by improper use.
Structural steel plays an important role in many industries, such as construction and engineering, and contributes a lot to the society. In order to meet the needs of production, China has made a lot of efforts in the development and application of structural steels, and has formed a relatively perfect system of structural steel production and use.
