Fasteners are also called standard parts in the market, and are a general term for a class of mechanical parts used when two or more parts (or components) are fastened and connected to form a whole. It is characterized by a wide variety of specifications, different performance and use, and a high degree of standardization, serialization, and generalization. Fasteners are the most widely used mechanical base parts and are in great demand.
1. Dimensional standards for fastener products: specify the basic dimensions of the product; products with threads also include the basic dimensions of the threads, thread end, shoulder distance, undercuts and chamfers, and the ends of external threaded parts Dimensions and more.
2. Standards for technical conditions of fastener products. Specifically includes the following standards:
a) Standards for fastener product tolerances: specify the content of product size tolerances and shape and position tolerances.
b) Standards for mechanical properties of fastener products: specify the marking methods of mechanical performance grades of products and the contents of mechanical performance items and requirements; some fastener products change this content to product material performance or working performance Aspect.
c) Standards for surface defects of fastener products: specify the types and specific requirements of product surface defects.
d) Standards for surface treatment of fastener products: specify the surface treatment types and specific requirements of the product.
e) Standards for testing of fastener products: specify the content of the above various performance requirements testing.
3. Standards for the inspection, marking and packaging of fastener products: Specifically specify the quality level and sampling plan of sampling inspection items during the factory acceptance inspection, as well as the content of product marking methods and packaging requirements.
4. Standards for marking methods of fastener products: specify the content of complete marking methods and simplified marking methods of products.
5. Standards for other aspects of fasteners: such as standards for terms of fasteners, standards for weight of fastener products, etc.