Custom countersunk head carbon steel cross drive black zinc plating screw

Industry knowledge：

Screw Material Knowledge

At present, the standard parts on the market mainly include carbon steel, stainless steel and copper.
1. Carbon steel. We distinguish low carbon steel, medium carbon steel and high carbon steel and alloy steel by the content of carbon in carbon steel material.
1.1. Low carbon steel C%≤0.25% is usually called A3 steel in China. Foreign countries are basically called 1008, 1015, 1018, 1022, etc. Mainly used for grade 4.8 bolts, grade 4 nuts, small screws and other products without hardness requirements. (Note: The drill tail screw is mainly made of 1022 material.)
1.2. Medium carbon steel 0.25%
1.3. High carbon steel C%>0.45%. Basically not used in the market.
1.4. Alloy steel: Add alloying elements to ordinary carbon steel to increase some special properties of steel: such as 35, 40 chromium molybdenum, SCM435, 10B38. Fangsheng screws mainly use SCM435 chromium molybdenum alloy steel, the main components are C, Si, Mn, P, S, Cr, Mo.
2.stainless steel. Performance grades: 45, 50, 60, 70, 80.
2.1. Mainly divided into austenite (18%Cr, 8%Ni) with good heat resistance, good corrosion resistance and good weldability. A1, A2, A4.
2.2. Martensite and 13%Cr have poor corrosion resistance, high strength and good wear resistance. C1, C2, C4 ferritic stainless steels. 18%Cr has better upsetting and corrosion resistance than martensite. The imported materials on the market are mainly Japan. According to the level, it is mainly divided into SUS302, SUS304 and SUS316.
3. copper. Commonly used materials are brass…zinc-copper alloys. The market mainly uses H62, H65, H68 copper as standard part.