Material of Locking Nut

Locking nut is a kind of nut widely used in machinery and other industries. Its working principle is self-locking by friction between nut and bolt. But the reliability of this self-locking will be reduced in dynamic load. On some important occasions, we will take some measures to prevent loosening to ensure the reliability of nut locking.
At present, there are mainly three kinds of locking nuts on the market: carbon steel, stainless steel and copper.
(1) Carbon steel. We distinguish low-carbon steel, medium-carbon steel, high-carbon steel and alloy steel by carbon content in carbon steel.
1. Low carbon steel C%<0.25% is commonly referred to as A3 steel in China. Foreign countries are basically called 1008, 1015, 1018, 1022, etc. Mainly used for 4.8 grade bolts and 4 grade nuts, small screws and other products without hardness requirements. (Note: Drilling tail nails are mainly made of 1022 materials.)
2. Medium carbon steel 0.25%<C%<0.45% is commonly referred to as No. 35 and No. 45 steel in China, while abroad it is basically referred to as No. 1035, CH38F, 1039 and 40ACR. It is mainly used for Grade 8 nuts, grade 8.8 bolts and grade 8.8 hexagonal products. 3. High carbon steel C%>0.45%. At present, there is little use in the market.
4. Alloy steel: Alloy elements are added to ordinary carbon steel to increase some special properties of steel, such as 35, 40 chromium-molybdenum, SCM435, 10B38. The aromatic screw mainly uses SCM435 chromium-molybdenum alloy steel, the main components are C, Si, Mn, P, S, Cr, Mo.

(2) Stainless steel. Performance Level: 45, 50, 60, 70, 80
Austenite (18% Cr, 8% Ni) has good heat resistance, corrosion resistance and weld ability. A1, A2, A4 martensite and 13% Cr have poor corrosion resistance, high strength and good wear resistance. C1, C2, C4 ferritic stainless steel. 18% Cr upsetting forging has better corrosion resistance than martensite. At present, the main imported materials in the market are Japanese products. According to the level, they are SUS302, SUS304 and SUS316.
(3) Copper. Commonly used material is brass. Zinc-copper alloy. In the market, H62, H65 and H68 copper are mainly used as locking nuts.