China's steel grade classification of representation

Carbon structural steel (1) by Q + number + quality grades of symbol + deoxidizing method symbol. Its steel grade dubbed 'Q', on behalf of the steel yield point, behind the figures show that the yield point value, the unit is MPa for example Q235 said the yield point ( σs） Carbon structural steel is 235 MPa. (2) can mark ShiGang number behind necessary said symbol of quality grade and deoxidation method. Quality grade symbol of A, B, C, D respectively. Deoxidizing method symbol: F rimming steel; B said half killed steel: Z said killed steel; TZ said special killed steel, killed steel standard symbols, namely, Z and TZ are not standard. For example Q235 - AF says a-class rimming steel. (3) special use of carbon steel, such as steel, Marine steel Bridges, basically use the representation method of carbon structural steel, but at the end of the steel grade of additional said use letters. High quality carbon structural steel (1) steel grade at the beginning of the two figures show that the carbon content of steel, with the average carbon content per few said, such as the average carbon content is 0. 45% of the steel, steel grade as '45', it is not a serial number, so I can't read into 45 # steel. (2) high quality carbon structural steel, manganese content shall be marked to manganese element, such as 50 mn. (3) the steel, half killed steel and special use of high quality carbon structural steel shall be marked on the last special steel grade, such as the average carbon content is 0. 1% of the half killed steel, the steel grade for 10 b. Carbon tool steel (1) steel grade dubbed the 'T', so as not to mix with other steel. (2) figures show that the carbon content of steel grade, with an average carbon content of a few parts per thousand. Such as 'T8' said average carbon content is 0. 8%. (3) high manganese content, in the final mark 'Mn' steel grade, such as 'T8Mn'. (4) high quality carbon tool steel of phosphorus, sulfur content, than the general high quality low carbon tool steel, filling at the end of the steel grade letter 'A', to show the difference, such as 'T8MnA'. Free cutting steel (1) steel grade as 'Y', to distinguish it from high quality carbon structural steel. (2) after the letter 'Y' figures show that the carbon content, with an average carbon content per few said, such as the average carbon content is 0. 3% of free cutting steel, the steel grade for 'Y30'. (3) high manganese content, also mark 'Mn' after the steel grade, such as 'Y40Mn'. Alloy structural steel (1) steel grade at the beginning of the two figures show that the carbon content of steel, with the average carbon content per few said, such as 40 cr. (2) main alloy element in steel, in addition to the individual microalloy element, usually expressed as a percentage. When the average alloy content < 1. 5%, generally only mark symbol in the steel grade, and not indicate content, but in special cases, easy to cause confusion, after the element symbol can be labeled with Numbers '1', such as steel grade 12 'crmov' and '12 cr1mov', the former chromium content is 0. 4 - 0. 6%, and the latter is 0. 9 - 1. 2%, all the rest of the ingredients are the same. When the average content of alloy element 1 or more. 5%、≥2. 5%、≥3. And so on. For example, 18 cr2ni4wa. (3) of the steel vanadium V, Ti, aluminum, titanium, boron, rare earth and alloy elements such as RE B, micro alloying elements, although the content is very low, still should be in steel grade drawings. 20 MNVB steel, for example. Vanadium is 0. 07 - 0. 12%, boron is 0. 001 - 0. 005%. (4) advanced high-quality steel should be in the steel grade