Fasteners include: bolts, studs, screws, nuts, washers, pin fasteners, also known as standard parts in the market. It is a kind of mechanical parts used for fastening connection, which is widely used. The characteristics of fasteners: : a wide variety of specifications, performance and use of different, and standardization, serialization, high degree of generalization. Therefore, some people have national (industry) standards of a class of fasteners called standard fasteners, referred to as standard parts.

As the specifications, dimensions, tolerances, weight, properties, surface conditions, marking methods, as well as the specific requirements for acceptance inspection, marking and packaging of each specific fastener product are specified separately in several national (industry) standards, such as British, German and American.

Fasteners are the most widely used mechanical base parts. Joined WTO along with our country 2001 and entered international trade big country cavalcade. A large number of Chinese fastener products are exported to other countries, and the fastener products from other countries are also pouring into the Chinese market. As one of the products with a large export volume, the realization of fastener is in line with international standards. It is of great significance and strategic significance to promote Chinese fastener enterprises to participate in international cooperation and competition.

Fastener is a general term for a class of mechanical parts used when two or more parts (or components) are fastened together into a whole. Also known as standard parts in the market.

It usually includes the following 12 types of parts: 1. Bolt: A type of fastener consisting of a head and a screw (a cylinder with an external thread). It needs to be fitted with a nut to fasten and connect two parts with a through hole. This form of connection is called bolt connection. If the nut is unscrewed from the bolt, the two parts can be separated, so the bolt connection is a detachable connection.

2. Stud: a type of fastener with no head and only external threads at both ends. When connected, one end of it must be screwed into the part with an internal threaded hole, the other end through the part with a through hole, and then screw on the nut, even if the two parts are fastened together into a single body. This form of connection is called stud connection, which is also a detachable connection. It is mainly used in the occasions where one of the connected parts has a large thickness, requires a compact structure, or is not suitable for bolted connection due to frequent disassembly.

3. Screw: It is also a kind of fastener composed of two parts: head and screw. According to the purpose, it can be divided into three categories: machine screw, set screw and special purpose screw. Machine screws are mainly used for the fastening connection between a part with a tight threaded hole and a part with a through hole, without nut fit (this connection form is called screw connection, also belongs to the removable connection; Can also be fitted with a nut for a tight connection between two parts with a through hole. The setting screw is mainly used to fix the relative position between two parts. Special purpose screws such as lifting ring screws are used for lifting parts.

4. Nuts: with internal threaded holes, the shape is generally shown as a flat hexagonal column, there are also flat square column or flat cylindrical, with bolts, studs or machine screws, used to fasten and connect the two parts, so that it becomes a whole.

5. Tapping screw: similar to machine screw, but the thread on the screw is for special tapping screw thread. Used for fastening and connecting two thin metal components, so that they become a whole, the component needs to make a small hole in advance, because this screw has high hardness, can be directly screwed into the hole of the component, so that the component of the formation of a response to the internal thread. This form of connection is also a detachable connection.

6. Wood screw: It is similar to machine screw, but the thread on the screw is special wood screw rib, can be directly screwed into the wood component (or part), used to fasten a metal (or non-metal) part with a through hole and a wood component together. This connection is also a removable connection.