The q235b steel plate consists of Q+number+quality grade symbol+deoxidation method symbol.
The steel number of the q235b steel plate is prefixed with "Q", which represents the yield point of the steel, and the following number represents the yield point value in MPa. For example, Q235 represents a carbon structural steel with a yield point (σs) of 235 MPa. When necessary, symbols indicating quality grade and deoxidation method can be marked after the steel number. The quality grade symbols are A, B, C, D, respectively.
Symbol of deoxidation method: F means boiling steel; b means semi-killed steel; Z means killed steel; TZ means special killed steel, and killed steel may not be marked with symbols, that is, Z and TZ may not be marked. For example Q235-AF means A-grade boiling steel.
Carbon steel for special purposes of carbon structural steel, such as bridge steel, marine steel, etc., basically adopts the representation method of carbon structural steel, but the letter indicating the purpose is added at the end of the steel number.
High quality carbon structural steel
The two digits at the beginning of the steel number indicate the carbon content of the steel, expressed in ten thousandths of the average carbon content. For example, for steel with an average carbon content of 0.45%, the steel number is "45", which is not a sequence number, so it cannot be read as 45 No. steel.
For high-quality carbon structural steel with high manganese content, the manganese element should be marked, such as 50Mn.
Boiling steel, semi-killed steel and high-quality carbon structural steel for special purposes should be specially marked at the end of the steel grade. For example, semi-killed steel with an average carbon content of 0.1% has a steel grade of 10b.
High-quality carbon structural steel is supplied by chemical composition and mechanical properties. The content of sulfur, phosphorus and non-metallic inclusions in the steel is small, indicating that the quality and uniformity of the structure are better, and it is often used in various important mechanical structural parts that require heat treatment.
According to the difference of chemical composition, high-quality carbon structural steel is divided into two types: ordinary manganese content steel and higher manganese content steel.
