What are the selection requirements of shaft processing?

The shaft is usually made of rolled round steel or forgings machined. Shaft diameter is smaller, can be made of round steel rod; Forgings are often used for important shafts with large diameter or large step diameter variation. To save metal and improve workability, shafts with large diameters can also be made of hollow shafts with welded or forged flanges. For shafts of complex shape (such as camshaft, crankshaft) can be cast.

1. Selection of shaft blank

For self-locking nut optical shaft or shaft segment diameter changes little, not too important shaft, can choose rolling rod as the shaft of the blank, can directly use cold drawn round steel; As for the important shaft bearing load, the shaft with large bearing load, and the stepped shaft with large change in diameter, the forging potter is generally adopted. For shafts with complex shapes, cast blanks are available.

2. Choose the material of the shaft according to the usage conditions

Many axes bear both torque and bending moment, and work under the condition of variable stress. Therefore, the material of the shaft should have better strength and toughness, and have better wear resistance when used for sliding bearing. Among them, high quality carbon structural steel is widely used, and 45 steel is the most commonly used. Less important shaft can also be used Q235, Q275 and other ordinary carbon structural steel. High speed, heavy load of the shaft, the larger force and require small size of the shaft and have special requirements of the shaft, to use alloy structural steel, such as chromium steel, chromium nickel steel, silicon manganese steel, etc.. Alloy steel has little sensitivity to stress concentration and is increasingly used in mechanical industry.

3. Heat treatment and surface treatment improve the mechanical properties of materials

Cold hardening is a mechanical surface treatment process, which can also be used to improve the surface quality of shafts and improve fatigue strength. The shot peening surface produces thin layer plastic deformation, and greatly reduces the surface roughness, hardening the surface, also can eliminate the micro crack, causes the surface to produce the residual compression stress.