What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
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.
A nut is a nut, a part that is screwed together with a bolt or screw for fastening. A component that must be used in all production and manufacturing machinery is divided into carbon steel, stainless steel, non-ferrous metals (such as copper), etc. several types.
An anti-falling nut, comprising a lock buckle 1, a lock plate 2, a nut body 3, a lock ring 4 and a lock claw 5, the lock ring 4 and the nut body 3 are used together, the lock ring 4 is a circular ring, and the lock ring 4 is a ring. The inner diameter of the ring 4 is larger than the inner diameter of the circumscribed circle of the nut body 3, the outer diameter of the lock ring 4 is smaller than the inner diameter of the lock 1, the lock plate 2 is an arc-shaped metal plate, and the number of the lock plates 2 is greater than or equal to three. One end of the short side is connected to the nut body 3, the other end of the lock plate 2 is connected to the lock pawl 5, the lock plate 2 is inclined to the outside of the nut body 3, and the lock buckle 1 is provided at the connection end of the lock pawl 5 and the lock plate 2. The outer side of the lock buckle 1 is a concave arc.
Today's advanced manufacturing represented by large aircraft, large power generation equipment, automobiles, high-speed trains, large ships, and large complete sets of equipment has entered an important development direction. As a result, fasteners will enter an important stage of development. High-strength bolts are used for the connection of important machinery, and repeated disassembly or various installation torque methods require extremely high-strength bolts. Therefore, the quality of its surface condition and thread accuracy will directly affect the service life and safety of the host. In order to improve the friction coefficient and avoid corrosion, seizure or sticking during use, the technical requirements stipulate that the surface should be treated with nickel phosphorus plating. The thickness of the coating is guaranteed to be within the range of 0.02 to 0.03 mm, and the coating is uniform, dense, and free of pinholes.
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