A kind of screw provided by Yueluo, the rod body of the screw rod has a thread segment, and the two ends of the thread segment are respectively provided with annular and two convex rings. The nominal size of the thread segment, and the distance from the convex ring at the rear end of the screw in the screwing direction to the rod core is greater than the nominal size of the thread segment.
When the countersunk head screws and hexagon socket head bolts are produced by the cold heading process, the original structure of the steel will directly affect the forming ability of the cold heading process. In the process of cold heading, the plastic deformation of the local area can reach 60%-80%, so the steel must have good plasticity. When the chemical composition of the steel is constant, the metallographic structure is the key factor to determine the plasticity. It is generally believed that the coarse flaky pearlite is not conducive to cold heading forming, while the fine spherical pearlite can significantly improve the plastic deformation ability of the steel. For medium carbon steel and medium carbon alloy steel with a large amount of high-strength bolts, spheroidizing (softening) annealing is performed before cold heading, so as to obtain uniform and fine spheroidized pearlite to better meet the actual production needs. For the softening annealing of medium carbon steel wire rods, the heating temperature should be kept above and below the critical point of the steel, and the heating temperature should not be too high, otherwise tertiary cementite will precipitate along the grain boundary, resulting in cold heading cracking. The wire rod of medium carbon alloy steel is annealed by isothermal spheroidization. After heating at AC1+ (20-30%), the furnace is cooled to slightly lower than Ar1, the temperature is about 700 degrees Celsius for an isothermal period, and then the furnace is cooled to about 500 degrees Celsius and air-cooled. The metallographic structure of the steel changes from coarse to fine, from flake to spherical, and the cracking rate of cold heading will be greatly reduced. The general area of softening annealing temperature for 35\45\ML35\SWRCH35K steel is 715-735 degrees Celsius; while the general heating temperature for spheroidizing annealing of SCM435\40Cr\SCR435 steel is 740-770 degrees Celsius, and the isothermal temperature is 680-700 degrees Celsius.
The technical problem to be solved by Guangdong Yueluo Hardware Industry Co., Ltd. is to overcome the deficiencies of the existing rivets. The purpose of this utility model is to provide a special rivet for railway freight cars, which can be reused and increase the safety factor. , to limit the movement of the collar in the circumferential direction.
The circlip is a common limiting element in the mechanical field, which is mainly used to limit the axial limit of mechanical parts. At present, the common circlips on the market are all circular rings with an opening. The circular ring has a certain elastic deformation capacity. When in use, the circlip can be detachably assembled to the mechanical on the part. However, the defect of the circlip adopting the one-piece ring is that the circlip is easily broken when frequently disassembled and used, and the service life is short.
screw is a common connecting piece, a tool that uses the physical and mathematical principles of the circular rotation and friction of an object to fasten the parts of the object step by step. Screws are indispensable industrial necessities in daily life: tiny screws used in cameras, glasses, clocks, electronics, etc.; general screws in televisions, electrical products, musical instruments, furniture, etc.; as for engineering, construction, and bridges, large screws are used. Screws and nuts; transportation equipment, airplanes, trams, automobiles, etc. are used together with large and small screws. Screws have important tasks in industry. As long as there is industry on earth, the function of screws will always be important. The screw is a common invention in people's production and life for thousands of years. According to the application field, it is a great invention of human beings. A traditional screw is generally set as a screw head at one end and a screw rod at the other end, which cooperates with an external nut to fasten the connector between the screw head and the nut. However, such as some home appliance modules, chassis and other electrical appliances, the modules and boxes fixed by traditional screws often fasten many parts together by screws. During maintenance, it is necessary to disassemble all parts of the maintenance part, which is very troublesome. Therefore, a new type of screw structure that can be connected at both ends and can realize layered installation is required. During maintenance, only the connecting layer of the maintenance part needs to be disassembled, and neither the exterior nor the interior needs to be disassembled.
We have many years of experience in the production and sales of screws, nuts, flat washers, etc. The main products are: GB6173 flat nuts with small teeth, six-star bakelite machine handle screws, gypsum board expansion bolts, GB37 pressure plate bolts and other products, we can provide you with suitable products. Your fastener solution.