Standard is to two or more than two parts (or components) fastening connection as a whole when adopted by a kind of general machinery parts, it is the most widely the application scope of national economic sectors, using the largest number of mechanical components, known as the "industrial meters," said, in a variety of machinery and equipment, vehicles ships, aircraft, satellites, railway Bridges, buildings, tools, equipment, instruments and articles for daily use such as above, use a variety of, considerable number of fasteners, such as a car on there are thousands of fasteners.
Fasteners is the feature of variety specification is various, performance different purposes, and high degree of standardization, seriation, generalization, so others called the existing national standards of fasteners, standard fasteners, or standard parts for short.
Fasteners are usually divided into bolt, stud, screws, nuts, self tapping screw, wood screw, washer, ring, pin, rivets, assembly and connection vice, welding and other 12 categories, at the same time some categories can also be based on its use, use material, strength grade, shape, and the way of surface treatment for a variety of different classification.
Fasteners are currently used in the automotive, electronics, construction and maintenance industries worldwide. Among them, the automobile industry is the largest user, accounting for 23.2% of the total sales volume of fasteners. The second is the maintenance industry market and the construction industry, accounting for about 20% of the total fastener sales. The third sector is the electronics industry, accounting for about 16.6 per cent of total fastener sales.