1. Appearance: The surface is smooth and flat, coated with anti-rust oil, the chamfer is smooth and no burrs. The surface must be free of defects such as black skin, cracks, folds, and inclusions.
2. Size: Check according to the drawings or sealed samples.
3. Surface roughness: The surface roughness is not greater than 3.2.
4. Hardness: Inspect according to the drawings or sealed samples.
5. Thread: The threaded end of the shaft with a nut should be tight.
6. Anti-rust test: 10% brine test does not rust.