The lock nut is a kind of nut widely used in machinery […]
The lock nut is a kind of nut widely used in machinery and other industries. Its working principle is to use the friction between the nut and the bolt for self-locking. However, the reliability of this self-locking under dynamic load will be reduced. In some important occasions, we will take some anti-loose measures to ensure the reliability of the nut locking.
At present, the lock nuts on the market mainly include carbon steel, stainless steel, and copper.
(1) Carbon steel. We distinguish low-carbon steel, medium-carbon steel, high-carbon steel, and alloy steel based on the carbon content of carbon steel materials.
1. Low carbon steel C%≤0.25% is usually called A3 steel in China. It is basically called 1008, 1015, 1018, 1022, etc. abroad. Mainly used for grade 4.8 bolts, grade 4 nuts, small screws and other products without hardness requirements. (Note: 1022 material is mainly used for drill tail nails.)
2, medium carbon steel 0.25%<c%≤0.45%, usually called No. 35 and No. 45 steel in China, and basically called 1035, ch38f, 1039, 40acr, etc. abroad. Mainly used for grade 8 nuts, grade 8.8 bolts and grade 8.8 inner hexagon products. <="" p="" style="margin: 0px; padding: 0px;">
3, high carbon steel C%>0.45%. Basically not used in the market at present
4. Alloy steel: Add alloy elements to ordinary carbon steel to increase some special properties of the 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.
Stainless steel. Performance level: 45, 50, 60, 70, 80
Is mainly divided into austenite (18%Cr, 8%Ni) with good heat resistance, good corrosion resistance and good weldability. 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 has better upsetting and corrosion resistance than martensite. Currently imported materials on the market are mainly Japanese products. According to the level, it is mainly divided into SUS302, SUS304, and SUS316.
(three) copper. Commonly used materials are brass...zinc-copper alloy. On the market, H62, H65, and H68 copper are mainly used as lock nuts.