The role and material of non-standard screws

Update:06 May 2020
Summary:

Non-standard screws are often used in daily life. They […]

Non-standard screws are often used in daily life. They are widely used in watches and glasses, train trains, and space shuttles. Screw is an invention in people's production. According to the application field, it is also the pride of human beings. So what are the ways to pay attention to the use of screws:
The role of non-standard screws:
The main role of non-standard screws is to link the tools to fasten the machine parts, which can also be called special-shaped screws. There are many screws that do not need nuts when connecting. Of course, the non-standard screws are basically non-standard screws, which play a key role in the link mechanism.


Non-standard screw material:
Generally speaking, the materials for manufacturing non-standard screws are high carbon steel, medium carbon steel, low carbon steel and other materials. The carbon content of carbon steel materials is divided into low carbon steel, medium carbon steel, high carbon steel and alloy steel. Low carbon steel C% ≤ 0.25% is commonly referred to as A3 steel in China. It is basically called 1008, 1015, 1018, 1022, etc. abroad. It is mainly used for products with no hardness requirements such as grade 4.8 bolts, grade 4 nuts and small screws. (Note: The 1022 material is mainly used for drilling screws.) Medium carbon steel 0.25% <C% ≤0.45% Usually referred to as No. 35 and No. 45 steel in China, and basically called 1035, CH38F, 1039, 40ACR etc. Mainly used for 8-level nuts, 8.8-level bolts and 8.8-level hexagonal products. High carbon steel C%> 0.45%. At present, alloy steel is basically not used in the market: alloy elements are added 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.