3. Carbon tool steel ① steel dubbed "T", so as not to be confused with other types of steel. ② The numbers indicate the carbon content of steel, with an average carbon content of a few thousandths of representation. For example "T8" represents the average carbon content of 0.8%. ③ higher manganese content in the steel last marked "Mn", for example "T8Mn". Phosphorus, sulfur ④ High quality carbon tool steel, than low-quality carbon tool steel, the steel final endorsement letter "A" in Linyi stainless steel rivets to distinguish, for example, "T8MnA". Stainless steel screws stainless steel screws 304 316 5 bolts. Alloy structural steel ① steel beginning of the two figures that the carbon content of steel, the average carbon content of the very few that, as 40Cr. ② major alloying elements in steel, in addition to individual micro-alloying elements, generally a few percent. When the average alloy content <1.5% Linyi stainless steel rings, screws, steel elements generally marked only symbols, not marked content Linyi stainless steel micro screw, but in exceptional circumstances prone to cause confusion, after the element symbol can also be marked with the The number "1", such as steel, "12CrMoV" and "12Cr1MoV", the former chromium content of 0.4-0.7% of Linyi, which is 0.9-1.2%, the remaining ingredients are all the same. When the average content of alloying elements ≥1.5%, ≥2.5%, while ≥3.5% ......, in the back of the element symbols should be marked content, can be expressed as the corresponding 2,3,4 ...... and so on. For example 18Cr2Ni4WA. Linyi 304 screws, Linyi, Jinan Road ground is provided by Jinan Daoqin Trading Company. Jinan Daoqin Trading Company (www.daoqinshangmao.com) (www.daoqinshangmao.com) strong, credible, in Jinan, Shandong hardware accessories industry has accumulated a large number of loyal customers. The company better work attitude and constantly improving innovative ideas will lead Jinan Road ground into the brilliant and you work for a better future!