Material knowledge of screws

At present, the standard parts on the market mainly include carbon steel, stainless steel and copper.
- carbon steel. We distinguish low carbon steel, medium carbon steel, high carbon steel and alloy steel according to the carbon content in carbon steel.
1 Low carbon steel C% ≤ 0.25% is generally called A3 steel in China. It is basically called 1008101510181022 in foreign countries. It is mainly used for grade 4.8 bolts, grade 4 nuts, small screws and other products without hardness requirements. (Note: The drilling tail nail is mainly made of 1022 material.)
2 carbon steel 0.25%
3 High carbon steel C%>0.45%. Basically not used in the market
4. Alloy steel: add alloy elements to ordinary carbon steel to increase some special properties of steel, such as 35, 40 CrMo, SCM435, 10B38. The aromatic screw is mainly made of SCM435 chrome-molybdenum alloy steel, with the main components of C, Si, Mn, P, S, Cr and Mo.
2. Stainless steel. Performance grade: 45, 50, 60, 70, 80
1. Main austenite (18% Cr, 8% Ni) has good heat resistance, corrosion resistance and weldability. A1，A2，A4
2 Martensite and 13% Cr have poor corrosion resistance, high strength and good wear resistance. C1, C2, C4 ferritic stainless steel. 18% Cr has good upsetting property and better corrosion resistance than martensite. The imported materials on the market are mainly from Japan. It is mainly divided into SUS302, SUS304 and SUS316 by level.
Three copper. Common materials are brass... zinc copper alloy. H62, H65 and H68 copper are mainly used as standard parts in the market.