There are many kinds of screw materials, and the general use can be divided into performance levels: carbon steel is used for grades below 6.8, low-carbon alloy steel is used for 8.8-10.9, medium carbon alloy steel is used for 10.9, and alloy steel is used for 12.9. , Grade 8.8 and above have been heat treated.
1, the screw is the use of the object bevel circular rotation and friction of physics and mathematics, step by step to tighten the tool parts. Screw is a general term for fastener.
2, screws for daily life indispensable industrial necessities: such as cameras, glasses, clocks, electronics, such as the use of small screws; General screws for TV sets, electrical products, Musical Instruments, furniture, etc. As for engineering, construction, bridge use large screws, nuts; Transportation equipment, aircraft, tram, car and so on are both large and small screws.
