It usually includes the following 12 categories of parts:

1. Bolt: A type of fastener consisting of a head and a screw (a cylinder with an external thread), which needs to be matched with a nut to fasten and connect two parts with through holes. This form of 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. Stud: a type of fastener without a head, only with external threads on both ends. When connecting, one end of it must be screwed into the part with the internal threaded hole, the other end must pass through the part with the through hole, and then the nut must be screwed on, even if the two parts are tightly connected as a whole. This form of connection is called a stud connection, which is also a detachable connection. It is mainly used for occasions where one of the connected parts is thick, requires a compact structure, or is not suitable for bolt connection due to frequent disassembly.


3. Screws: It is also a type of fastener composed of two parts: the head and the screw. According to the purpose, it can be divided into three categories: machine screws, set screws and special-purpose screws. Machine screws are mainly used for a fastened connection between a part with a fixed threaded hole and a part with a through hole, without the need for nut matching (this connection form is called screw connection, which is also a detachable connection; it can also be Cooperate with the nut, it is used for the fast connection between two parts with through holes.) The set screw is mainly used to fix the relative position between the two parts. Special purpose screws, such as eyebolts, are used for hoisting parts.


4. Nut: with internal threaded holes, the shape is generally flat hexagonal cylindrical shape, but also flat square cylindrical or flat cylindrical shape, with bolts, studs or machine screws, used to fasten and connect two parts, so that become a whole.


Special categories of nuts


High strength self-locking nut


It is a classification of self-locking nuts with high strength and reliability. It is mainly based on the introduction of European technology, which is used for road construction machinery, mining machinery, vibration machinery and equipment, etc. At present, there are very few domestic manufacturers of such products.


Nylon self-locking nut


Nylon self-locking nut is a new type of high anti-vibration and anti-loosening fastening parts, which can be used in various mechanical and electrical products with a temperature of -50 to 100 °C. At present, the demand for nylon self-locking nuts in aerospace, aviation, tanks, mining machinery, automobile transportation machinery, agricultural machinery, textile machinery, electrical products and various types of machinery has increased sharply, because its anti-vibration and anti-loosening performance is greatly improved. in various other


Anti-loose device, and the vibration life is several times or even dozens of times higher. At present, more than 80% of the accidents of mechanical equipment are caused by loose fasteners, especially in mining machinery, and the use of nylon self-locking nuts can prevent major accidents caused by loose fasteners.


5. Self-tapping screw: similar to machine screw, but the thread on the screw is a special self-tapping screw thread. It is used to fasten and connect two thin metal components to make them a whole. Small holes need to be made in advance on the components. Due to the high hardness of this kind of screw, it can be directly screwed into the hole of the component to make the component A responsive internal thread is formed in it. This form of connection is also a detachable connection.


6. Wood screw: It is also similar to machine screw, but the thread on the screw is a special rib for wood screw, which can be directly screwed into the wooden component (or part) to connect a metal (or non-metal) with a through hole. The parts are fastened together with a wooden element. This connection is also a detachable connection.


7. Washers: a type of fastener with an oblate ring shape. It is placed between the supporting surface of the bolt, screw or nut and the surface of the connecting part, which increases the contact surface area of the connected parts, reduces the pressure per unit area and protects the surface of the connected parts from damage; another type of elastic washer, It can also play a role in preventing 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 the hole from moving left and right.


9. Pins: mainly used for parts positioning, and some can also be used to connect parts, fix parts, transmit power or lock other fasteners.


10. Rivet: A type of fastener consisting of a head and a shank, which is used to fasten and connect two parts (or components) with through holes to make them a whole. This form of connection is called rivet connection, or riveting for short. It belongs to the non-detachable connection. Because to separate the two parts that are joined together, the rivets on the parts must be broken.


11. Assemblies and connection pairs: Assemblies refer to a type of fasteners supplied in combination, such as a combination supply of certain machine screws (or bolts, self-supplied screws) and flat washers (or spring washers, lock washers); connection Auxiliary refers to a type of fasteners supplied by a combination of special bolts, nuts and washers, such as high-strength hexagon head bolts for steel structures.


12. Welding nails: Due to the heterogeneous fasteners composed of light energy and nail heads (or no nail heads), they are fixed and connected to a part (or component) by welding so as to be connected with other parts.