Fasteners are a type of mechanical part used for fastening connections and are extremely widely used. Fasteners are used in a wide range of industries, including energy, electronics, electrical appliances, machinery, chemicals, metallurgy, molds, hydraulics, and many others. Various types of fasteners can be found in all kinds of machinery, equipment, vehicles, ships, railways, bridges, buildings, structures, tools, instruments, chemical equipment, meters, and supplies, making them the most widely used basic mechanical components.
Their characteristics include a wide variety of types and specifications, diverse performance and uses, and a very high degree of standardization, serialization, and generalization. Therefore, some people refer to a class of fasteners that have existing national standards as standard fasteners, or simply standard parts.