Stainless steel Fastenings is a kind of mechanical parts used for fastening connections and is widely used. Fastenings are characterized by diverse varieties, different functions and uses, and a high degree of standardization, serialization and generalization. Therefore, some people call a kind of Fastenings in the existing national (professional) specifications as standard Fastenings, or standard Fastenings for short.
Each detailed Fastenings product specifications, scale, service, weight, function, appearance condition, symbol method, and detailed requirements for inspection, marking and packaging are stipulated in some national (professional) specifications.
Fastenings are the most widely used mechanical basic parts. With China's accession to the WTO in 2001, it has entered the ranks of the world's major trading nations. China's Fastenings products are exported to many countries in the world, and Fastenings products from all over the world have also poured into the Chinese market. Fastenings is one of China's largest import and export products. It is of great strategic significance to promote Chinese Fastenings companies to go global and to promote Fastenings companies to fully participate in world cooperation and competition.
Fastenings is a general term for mechanical parts used when two or more parts (or components) are fixed and connected into a whole. Also known as the normative part in the market. It usually includes the following 12 types of parts:
1. Bolt: A kind of Fastenings consisting of a head and a screw (cylinder with external thread), which needs to be matched with a nut to fasten and connect the two parts through a through hole. This connection is called a bolted connection. If the nut is unscrewed from the bolt, the two parts can be separated, so the bolt connection is a detachable connection.
2. Bolt: a kind of Fastenings without a head and with external threads at both ends. When connecting, even if the two parts are tightly connected into a whole, one end must be screwed into the part with the internal threaded hole, the other end must be passed through the part with the through hole, and then the nut must be tightened. This kind of connection is called a stud connection, and it is also a separable connection. It is mainly used when one of the parts to be connected is thick, requires a compact structure or is not suitable for bolt connection due to frequent disassembly.
3. Screw: This is also a kind of Fastenings composed of heads and screws. According to the purpose, it can be divided into three categories: machine screws, set screws and special screws. Machine screws are mainly used for the fastening connection between parts with fixed threaded holes and parts with through holes, and no nut is required (this connection method is called screw connection, which is also a detachable connection; it can) tighten the screw It is mainly used to fix the relative direction between two parts, and special screws such as eye bolts are used to lift the parts.
4. Nut: with internal threaded hole, the shape is usually flat hexagonal column shape, it can also be flat square column shape or flat cylindrical shape. Use bolts, stud bolts or machine screws to fix and connect the two parts together to make them integral.
5. Self-tapping screw: similar to machine screws, but the thread on the screw is a special self-tapping screw thread. It is used to fix and connect two thin metal parts to form a whole. Need to punch holes in the component in advance. Due to the high hardness of the screw, the screw can be directly screwed into the hole of the component to form a corresponding internal thread. This connection is also a detachable connection.
6. Wood screws: also similar to machine screws, but the threads on the screws are special ribs for wood screws, which can be screwed directly into wood components (or parts) for fixing and connecting metal (or non-metal) with through holes Parts with wooden parts. This cohesion is also attributed to the ability to separate cohesion.
7. Washer: a flat round Fastenings. It is placed between the support surface of the bolt, screw or nut and the outer surface of the connecting part, which can increase the volume of the contact surface of the connecting part, reduce the pressure per unit area, and protect the surface of the connecting part from damage; another elastic washer It can also prevent the nut from loosening.
8. Retaining ring: It can be installed in the shaft groove or hole groove of the machine and equipment to prevent the parts from moving left and right on the shaft or hole.
9. Pin: Mainly used for positioning parts.