1. Standards for fastener product size: specify the basic dimensions of the product; threaded products, including basic thread size, thread finish, shoulder distance, undercut and chamfer, external thread The end size of the part and so on.

2. Standards for technical conditions of fastener products. It mainly includes product tolerances, mechanical properties, surface defects, surface treatment, product testing standards and corresponding specific provisions.

3. Standards for inspection, marking and packaging of screw products: specify the quality level and sampling plan of the project, and the product marking method and packaging requirements.