Fastener is a kind of mechanical part which is used for fastening connection and widely used. Fasteners, widely used in industry, including energy, electronics, electrical appliances, machinery, chemical, metallurgy, mold, hydraulic and other industries, in a variety of machinery, equipment, vehicles, ships, railways, bridges, buildings, structures, tools, instruments, chemicals, instruments and supplies, all kinds of fasteners can be seen,
Is the most widely used mechanical base piece. It is characterized by a variety of specifications, the performance of different uses, and standardization, serialization, the degree of generalization is also very high. Therefore, some people have the national standards of a class of fasteners known as standard fasteners, or simply referred to as standard pieces.