Service HotlineSemi-round head plastic screws have high-quality characteristics such as insulation, non-magnetic, corrosion resistance, beautiful appearance, and never rust, and modified engineering plastics, its strength and impact resistance are comparable to those of metals. The plastic screws we often say are commonly known as nylon. After adding 30% glass fiber to the screw, its mechanical properties are far superior to ordinary nylon. The materials used for the dome head plastic screws are becoming more and more diverse, the performance is constantly improving, and the application fields are becoming wider and wider. 1. Medical equipment industry (insulation, non-magnetic, environmental protection, anti-interference, make medical equipment safer to use) 2. Wind power industry (isolation and insulation of chassis circuit PCB boards) 3. Aerospace industry (electronic equipment Insulation, anti-interference) 4. Office equipment industry (never rust, beautiful and practical) 5. Petrochemical industry (high temperature resistance, chemical resistance, corrosion resistance, prolong equipment life) 6. Electronics industry (insulation, anti-interference) , light weight) 7. Communication industry (insulation, non-magnetic, safety) 8. Ship industry (acid resistance, alkali resistance, corrosion resistance, extended service life), etc... .
Several concepts about high-strength bolts 1. According to the specified performance level of bolts above 8.8, they are called high-strength bolts. The current national standard only lists M39. For large-size specifications, especially those with a length greater than 10 to 15 times High-strength bolts, domestic production is still short-term. The difference between high-strength bolts and ordinary bolts: High-strength bolts can withstand larger loads than ordinary bolts of the same specification. High-strength outer hexagon bolts High-strength outer hexagon bolts are made of Q235 (ie A3). The material of high-strength bolts is 35# steel or other high-quality materials, which are heat-treated after being made to improve the strength. The difference between the two is the difference in material strength. From raw materials: High-strength bolts are made of high-strength materials. The screws, nuts and washers of high-strength bolts are all made of high-strength steel, such as No. 45 steel, 40 boron steel, 20 manganese titanium boron steel, 35CrMoA, etc. Ordinary bolts are usually made of Q235 (equivalent to A3 in the past) steel. In terms of strength grades: high-strength bolts are increasingly used. Two strength grades are commonly used, 8.8s and 10.9s, of which 10.9 is the majority. The strength level of ordinary bolts is lower, generally 4.4, 4.8, 5.6 and 8.8. High-strength bolts High-strength bolts are viewed from the force characteristics: high-strength bolts apply pretension and transmit external forces by friction. Ordinary bolt connection relies on the shear resistance of the bolt and the bearing of the hole wall to transmit the shear force. When the nut is tightened, the pre-pressure is very small, and its influence can be ignored. In addition to its high material strength, high-strength bolts also exert a large amount of pressure on the bolts. The pre-pressure generates extrusion force between the connecting components, so that there is a large friction force perpendicular to the direction of the screw, and the pre-pressure, anti-slip coefficient and steel type directly affect the bearing capacity of high-strength bolts. According to the force characteristics, it is divided into pressure type and friction type. The calculation methods of the two are different. The minimum specification of high-strength bolts is M12, and M16~M30 are commonly used. The performance of super-large bolts is unstable and should be used with caution in design.
With the development of science and technology, the advancement of technology, the rapid change of automotive products, also put forward higher requirements for fastener products, and automotive fastener-related products, especially in the process of assembling auto parts, in order to effectively improve the bolts The fastening strength is mostly made of combined gaskets (flat gaskets, cone gaskets) and riveted nuts to meet the assembly requirements.
There are many types of rivets, including dome head, flat head, blind rivet and so on. When riveting parts, they will have uneven force and affect the quality of riveting. Some rivet caps are too thin to easily affect the quality of riveting. Some rivets have poor tightness of riveted parts when riveting. Therefore, both the structure of the rivet and the tightness of the riveting need to be considered, so as to enhance the quality of the rivet fastening.
High-strength bolt connection has the advantages of simple construction, good mechanical performance, disassembly and replacement, fatigue resistance, and no loosening under dynamic load. It is a promising connection method. High-strength bolts use a special wrench to tighten the nut, so that the bolt generates a huge and controlled pre-tension. Under the action of pre-pressure, a large frictional force will be generated along the surface of the connected parts. Obviously, as long as the axial force is less than this frictional force, the components will not slip and the connection will not be damaged. This is the high-strength bolt connection. principle. High-strength bolted connections rely on the friction between the contact surfaces of the connectors to prevent them from sliding each other. In order to make the contact surfaces have sufficient friction, it is necessary to increase the clamping force of the components and increase the friction coefficient of the contact surfaces of the components. The clamping force between the components is achieved by applying pretension to the bolts, so the bolts must be made of high-strength steel, which is why it is called high-strength bolted connections. In high-strength bolted connections, the friction coefficient has a great influence on the bearing capacity. Tests show that the coefficient of friction is mainly affected by the form of the contact surface and the material of the components. In order to increase the friction coefficient of the contact surface, methods such as sandblasting and wire brush cleaning are often used to treat the contact surface of the components within the connection range during construction.
We have many years of experience in the production and sales of screws, nuts, flat washers, etc. The main products are: 12.9 high-strength screws, GB1339 hexagonal self-locking nuts, extra-large washers, galvanized countersunk nuts and other products, we can provide you with suitable for your products. Fastener Solutions.
