Non-standard screws are often used in daily life

Non-standard screws are often used in daily life, and they are widely used in watch glasses, large trains, and space shuttles. Screws are an invention in people’s production. According to the field of application, it is also the pride of mankind. So what are the ways to use the screws:
The role of non-standard screws:
The main function of non-standard screws is to link the tools that fasten the parts, which can also be called special-shaped screws. There are a lot of screws that can be used without the nuts when connecting. Of course, the basic non-standard screws that do not use the nut play a key role in the link mechanism.
Non-standard screw material:
In general, the material for manufacturing non-standard screws is high carbon steel, medium carbon steel, low carbon steel and other materials. The carbon content of carbon steel is distinguished from low carbon steel, medium carbon steel, high carbon steel and alloy steel. Low carbon steel C% ≤ 0.25% Domestically known as A3 steel. Foreign countries are basically called 1008, 1015, 1018, 1022 and so on. Mainly used for 4.8-class bolts, 4-level nuts, small screws and other products without hardness requirements. (Note: The drill tail nail is mainly made of 1022 material.) Medium carbon steel 0.25% 0.45%