What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Welding stud is also called welding screw, which belongs to a kind of fastener connected with high strength and rigidity. Welding stud is the abbreviation of cylindrical head welding stud for arc stud welding. Industrial plant construction, highways, railways, bridges, towers, automobiles, energy, transportation facilities, airports, stations, power stations, pipeline supports, lifting machinery and other types of steel structures and other projects.
screw with a gasket aims to provide a screw with a gasket that improves installation efficiency. The technical solution of the screw is that after the screw cap, the connecting rod and the screw rod are processed, the gasket with the installation through hole is processed. The installation through hole is drilled through the connecting rod, and then the end of the screw rod opposite to the connecting rod is processed to form a convex tooth structure by extrusion. At the same time, the outer diameter of the tooth peak of the convex tooth is larger than the inner diameter of the installation through hole, so that the gasket is not easy to be installed. Falling off, the step of manually wearing the gasket is reduced, that is, the workload of the staff is reduced, and the installation efficiency is relatively high. The flange increases the contact area between the screw cap and the gasket, and enhances the friction between the screw cap and the gasket, which can prevent the screw from loosening easily after being fastened and installed, thereby improving the connection stability of the screw. When installing the screw, the fixing part can be snapped into the fixing groove on the installation plane, so as to avoid the washer from rotating with the rotation of the screw when the screw is tightened, which is convenient for the tightening and installation of the screw.
The grooved embedded parts are pre-embedded in concrete, and then placed in the groove with T-bolts. After adjusting the fixed position, the fixed object is locked with a nut to achieve the fixing effect. When the grooved embedded parts are embedded vertically in the concrete or at a certain angle to the horizontal line, the T-bolts are likely to move in position before they are tightened. In particular, when fixing heavy equipment, multiple T-bolts are required, and multiple groups of workers are required to help and positioning is difficult, and the installation process is complicated.
High-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.
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