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Popularization of valve fastener product knowledge
Source: | Author:pmt76469a | Published time: 2020-05-13 | 1014 Views | Share:
Valve fasteners are indispensable for valve products. Fasteners are a kind of mechanical parts used for fastening and connection, which are widely used. The characteristics of fasteners are various in variety, specification, performance and use, and the degree of standardization, serialization and generalization is very high. Therefore, some people also call the class I fastener of national (industry) standard as standard fastener, which is called standard fastener for short.
Valve fasteners are indispensable for valve products. Fasteners are a kind of mechanical parts used for fastening and connection, which are widely used. The characteristics of fasteners are various in variety, specification, performance and use, and the degree of standardization, serialization and generalization is very high. Therefore, some people also call the class I fastener of national (industry) standard as standard fastener, which is called standard fastener for short.
Due to the specification, dimension, tolerance, weight, performance, surface condition, marking method of each specific fastener product, as well as the specific requirements of acceptance inspection, marking and packaging, etc., they are respectively specified in several national (industry) standards, such as British system, German system and American system.
Fastener is the most widely used mechanical foundation. With China's accession to the WTO in 2001, China has entered the ranks of a great power in international trade. China's fastener products are exported to many countries all over the world, and the fastener products from all over the world are also pouring into the Chinese market. As one of the products with a large import and export volume in China, the realization of fasteners in line with international standards is of great significance and strategic significance to promote Chinese fastener enterprises to go to the world and to promote fastener enterprises to participate in international cooperation and competition in an all-round way.
Fastener is the general name of a kind of mechanical parts used when two or more parts (or components) are fastened and connected as a whole. Also known as standard parts on the market.
It usually includes the following 12 categories of parts:
1. Bolt: a kind of fastener composed of head and screw (cylinder with external thread), which needs to be matched with nut to fasten and connect two parts with through hole. This kind of connection is called bolt connection. If the nut is unscrewed from the bolt, the two parts can be separated, so the bolt connection belongs to the detachable connection.
2. Stud: a type of fastener without head, only with thread on both ends. When connecting, one end of it must be screwed into the part with the internal thread hole, the other end must be threaded into the part with the through hole, and then screw on the nut, even if the two parts are firmly connected as a whole. This kind of connection is called stud connection, and it also belongs to detachable connection. It is mainly used in the occasion where one of the connected parts is thick, requires compact structure, or is not suitable for bolt connection due to frequent disassembly.
3. Screw: it is also a kind of fastener composed of head and screw. It can be divided into three types according to the purpose: machine screw, set screw and special purpose screw. The machine screw is mainly used for the fastening connection between a part with a set screw hole and a part with a through hole, without nut matching (this connection form is called screw connection, which is also a detachable connection; it can also be used for the fastening connection between two parts with a through hole) Set screw is mainly used to fix the relative position between two parts. Special purpose screws such as eyebolts are used for lifting parts.
4. Nut: with internal thread hole, the shape is generally in the form of flat hexagon column, but also in the form of flat square column or flat cylinder. It is used to fasten and connect two parts with bolt, stud or machine screw, so as to make them become a whole.
5. Self tapping screw: similar to the machine screw, but the thread on the screw is the special thread for self tapping screw. It is used to fasten and connect two thin metal components to form a whole. Small holes need to be made on the components in advance. Because of the high hardness of this screw, it can be directly screwed into the holes of the components to form a responsive internal thread in the components. This kind of connection also belongs to detachable connection.
6. Wood screw: it is also similar to the machine screw, but the screw thread on the screw is a special wood screw with rib, which can be directly screwed into the wood components (or parts) for fastening and connecting a metal (or non-metal) part with a through hole with a wood component. This connection is also a detachable connection.
7. Washer: a kind of fastener with flat circular shape. It is placed between the support surface of bolt, screw or nut and the surface of the connecting part to increase the contact surface area of the connected part, reduce the pressure per unit area and protect the surface of the connected part from damage; another type of elastic washer can also prevent the nut from loosening.
8. Retaining ring: it is installed in the shaft groove or hole groove of the machine and equipment, and plays the role of preventing the parts on the shaft or hole from moving left and right.
9. Pin: it is mainly used for parts positioning, and some can also be used for parts connecting, fixing parts, transferring power or locking other fasteners.
10. Rivet: a kind of fastener composed of head and pin rod, which is used to fasten and connect two parts (or components) with through holes to make them become a whole. This kind of connection is called rivet connection, which is short for riveting. It is connected with non detachable. Because in order to separate the two parts connected together, the rivets on the parts must be broken.
11. Assembly and connection pair: assembly refers to a kind of fastener supplied by combination, such as the combination of a certain machine screw (or bolt, self supplied screw) and flat washer (or spring washer, lock washer); connection pair refers to a kind of fastener supplied by combination of a certain special bolt, nut and washer, such as high-strength large hexagon head bolt connection pair for steel structure.
12. Welding pin: due to the different fastener composed of light energy and nail head (or without nail head), it is fixed on one part (or component) by welding method, so as to connect with other parts.
Each fastener product