Spring pin High strength elastic cylindrical pin Spring pin M10 M12

Round head three combination screw, also known as pan head three combination screw, can be divided into large pan head three combination screw and small pan head three combination screw, also known as round head machine wire spring flat pad three combination screw. The materials are divided into stainless steel and iron. The round head triple screw of stainless steel includes stainless steel small pan head triple screw and stainless steel large pan head triple screw. Represented as GB9074.8 and GB9074.4 in national standards.

"1. Material strain hardening
During cyclic loading, materials may experience "cyclic strain hardening" or "cyclic strain softening", meaning that under constant amplitude cyclic strain, the stress amplitude will increase or decrease with the increase of the number of cycles. After several cycles, the stress amplitude enters a cyclic stable state. The Low-cycle fatigue of the lock nut is carried out under the condition that the strain is constant, and the strain hardening or softening of the thread piece will affect the maximum screw out torque. The alloy steel used for manufacturing lock nuts belongs to the cyclic strain hardening material. Material hardening will increase the elastic recovery force FN of the threaded piece and increase the tightening torque"

Cylindrical pins are generally used for connecting, locking parts, or for assembly positioning, and can also be used as parts of safety devices. The cylindrical pin is fixed in the pin hole through an interference fit with the pin hole, used to fix parts, transmit power, or serve as a positioning component. The existing technology of cylindrical pin press fitting is shown in Figure 1. This type of cylindrical pin prevents the cylindrical pin from exiting by the locking force and axial friction force brought by the interference fit between the cylindrical pin body and the pin hole. However, during use, the interference amount of the cylindrical pin body will gradually decrease, resulting in a gradual decrease in the firmness and positioning accuracy of the connection. Therefore, this type of cylindrical pin is easy to exit during use, resulting in safety hazards.

1. Ordinary outer hexagonal wrench - widely used, characterized by a relatively large tightening force. The disadvantage is that there must be sufficient operating space during installation, and adjustable wrenches, open-end wrenches, or eyeglass wrenches can be used during installation. All of these wrenches require a large amount of operating space. 2. Cylindrical head hexagon socket is the most widely used screw among all screws. Because of its large tightening force, it can be operated by using a Hex key. It is very convenient to install, almost used in various structures, and has a beautiful and tidy appearance. The disadvantage is that the tightening force is slightly lower than the outer hexagon. In addition, repeated use is easy to damage the inner hexagon socket, which can not be removed. 3. Pan head inner hexagon - rarely used mechanically, with the same mechanical properties as before, mostly used in furniture. Its main function is to increase the contact surface with wooden materials and enhance the aesthetic appearance. 4. Headless hexagonal socket - must be used on certain structures, such as top wire structures that require significant tightening force or places where cylindrical heads need to be hidden. 5. Countersunk hexagonal socket - mostly used in power machinery, its main function is the same as that of hexagonal socket. 6. Nylon lock nut - a structure with nylon rubber rings embedded in the hexagonal surface to prevent thread loosening, used in powerful machinery. 7. Flange nut - mainly plays the role of increasing the contact surface with the workpiece, mostly used in pipes, fasteners and some stamping and casting parts. 8. Ordinary hex nuts - the most versatile and commonly used fasteners.

"Drill tail screws have been a new invention by people in recent years. Screws are a common term for fasteners, commonly used in everyday language.
The tail of the drill tail screw is in the shape of a drill tail or pointed tail, without the need for auxiliary processing. It can be directly drilled, tapped, and locked on the setting material and foundation material, greatly saving construction time. Compared to ordinary screws, they have high toughness and maintenance force, and will not loosen after being combined for a long time. It is easy to use safe drilling and tapping to complete the operation in one go.
Drill tail screw
Drill tail screw
Usage: It is a type of screw, mainly used for fixing colored steel tiles in steel structures, and can also be used for fixing thin plates in simple buildings. It cannot be used for metal to metal bonding fixation. Material and model
There are two types of materials: iron and stainless steel, among which stainless steel is divided into various materials.
The models include: Φ 4.2/ Φ 4.8/ Φ 5.5/ Φ 6.3mm, specific length can be agreed upon according to requirements.
According to different drilling tails, they can be further divided into:
Round head rice/cross/plum blossom, countersunk head (flat head)/rice/cross/plum blossom, hexagonal Huasi, round head Huasi (large flat head), trumpet head, etc"