Service HotlineHigh-strength fastener materials mainly include ML35, 35K, ML40Cr, ML35CrMo steel, etc., of which 75ML35CrMo steel is imported. The main problems of the material are box segregation, decarburization, cracks and so on. The material needs to be spheroidized and annealed before cold forming, and the annealing is carried out in an oil furnace. There is no protective atmosphere in the furnace, and there is a decarburization phenomenon. 1.2 The high-strength fasteners, mainly grade 12.9, are quenched and tempered on the chain casting furnace production line. The temperature and atmosphere in the furnace are controlled by computer, and Rx gas is used as a protective atmosphere. Heating and anti-oxidation and decarburization can be effectively controlled, and the quality of the fasteners is intact during the heating process. The high-strength fasteners mainly of grade 8.8 are quenched and tempered on the vibrating hearth furnace. Affected by the structure of the vibrating hearth furnace, the sealing performance of the furnace is poor, the Rx atmosphere is not easy to control, the temperature difference of the furnace is large, and the parts are heated in the furnace. The collision and the length of time are inconsistent, and the quality of the fasteners during the heating process is poor, and there are phenomena such as decarburization, bumps, and uneven heating.
Screws are commonly found in machinery, electrical appliances and buildings. They are generally made of metal or plastic, cylindrical in shape, and grooves engraved on the surface are called screw threads. The main function of the screw is to join two objects, or to fix the position of an object. Screws can often be removed or re-tightened at will without compromising their efficiency. Generally, the diameter of the top of the screw is larger, and the common ones are round, square or regular hexagon. If the top is regular hexagon, you can turn the screw with a wrench. If the top is round, there will also be grooves on the front of the top, which is convenient for use screwdriver to turn the screw. *The common grooves are one-shaped, cross-shaped and square, and there are other shapes. The grooves of the existing screws are often easy to wear, which makes the screws inconvenient to use and causes the screws to be scrapped. In addition, because the screws have no chip removal The structure makes it difficult for the screw to penetrate other objects, which affects the efficiency of the screw.
In industrial production, some products need to remove the fixing screws; or in the assembly line, the screws that fix the product on the fixture also need to be removed when the product is unloaded. At present, the dismantling of the screws is mainly completed by the manual operation of the operator. However, this method of manually dismantling the screws has low work efficiency and high production cost.
When people use a screwdriver and other tools to screw a screw into an object, they need one hand to hold the screw and the other to hold the screwdriver and other tools, which brings some inconvenience to the user; especially when the screw is not correctly set, it will cause work and time delays, affecting work efficiency. .
The difference between high-strength bolt friction type and pressure-bearing type connection: High-strength bolt high-strength bolt connection is to clamp the plate of the connecting plate through a large tightening pre-pressure in the bolt rod, which is enough to generate a large friction force, thereby improving the connection. The integrity and stiffness of the bolt can be divided into two types: high-strength bolt friction type connection and high-strength bolt pressure type connection according to different design and force requirements when subjected to shear force. The essential difference between the two is that the limit state is different, although It is the same kind of bolt, but it is very different in terms of calculation method, requirements, and scope of application. In the shear design, the friction type connection of high-strength bolts is the limit state when the external shear force reaches the possible maximum friction force provided by the bolt tightening force between the contact surfaces of the plates, that is, the internal and external shear force of the connection is guaranteed not to exceed maximum friction. The plate will not undergo relative slip deformation (the original gap between the screw and the hole wall is always maintained), and the connected plate will be elastically stressed as a whole. In the design of shear resistance, the external shear force is allowed to exceed the maximum friction force in the high-strength bolt-bearing connection. At this time, relative slip deformation occurs between the connected plates until the bolt rod contacts the hole wall, and then the connection depends on the bolt rod. The shearing of the body and the bearing of the hole wall and the friction between the contact surfaces of the plates jointly transmit the force, and finally the shearing of the shaft or the bearing of the hole wall is regarded as the limit state of the connection shearing. In a word, friction type high-strength bolts and pressure-bearing high-strength bolts are actually the same type of bolts, but whether the design considers slippage. Friction type high-strength bolts can never slide, and the bolts do not bear shear force. Once slipped, the design is considered to reach a state of failure, which is technically mature; pressure-bearing high-strength bolts can slide, and the bolts also bear shear force, and the final damage is equivalent to ordinary Bolt failure (bolt shearing or steel plate crushing).
We have many years of experience in the production and sales of screws, nuts, flat washers, etc. The main products are: thickened square washers, cross recessed round head screws, national color screws, plum blossom countersunk head screws and bolts and other products, we can provide you with suitable products for you. Fastener Solutions.
