Each fastener product involves several criteria for several aspects:
1) Standards for the dimensions of fastener products: specify the basic dimensions of the product; threaded products, including the basic dimensions of the thread, thread finish, shoulder distance, undercut and chamfer, end of externally threaded parts Dimensions and other aspects.
2) Standards for technical conditions of fastener products. Specifically, it includes the following standards:
a) Standards for fastener product tolerances: specify tolerances and shape tolerances for product dimensions.
b) Standards for mechanical properties of fastener products: specific marking methods for mechanical performance grades of products and mechanical performance items and requirements; some fastener products change this content to product material properties or work performance Aspect of the content.
c) Standards for surface defects of fastener products: specify the types of surface defects and specific requirements of the product.
d) Standards for surface treatment of fastener products: specify the types of surface treatment and specific requirements of the product.
e) Standards for the testing of fastener products: specify the test aspects of the above various performance requirements.
3) Standards for acceptance inspection, marking and packaging of fastener products: specify the quality level and sampling plan of the project, and the content of the product marking method and packaging requirements.
4) Standards for marking methods for fastener products: specific provisions for the complete labeling method and simplified marking method.
5) Standards for other aspects of fasteners: standards for fastener terminology, standards for fastener product weight, etc.
