What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The gasket side of the above-mentioned nut assembly is in contact with the mounting surface. When the nut is tightened, the gasket squeezes the outer cone surface to make it shrink, and the cone tip faces the same direction as the nut, thereby preventing the nut from tightening, so that the nut fixing effect is not good, and at the same time When multiple nuts need to be superimposed and fixed, two adjacent nuts cannot interact with each other, resulting in poor fixing effect.
In the process of mechanical assembly, we often use pins to connect two parts, and the positioning pins are usually sunk into the pin installation holes on the mechanical parts. During the assembly process or after the assembly is completed, we often need to pull out the pins to assemble, revise or repair the parts. The existing method of pulling out the positioning pins is generally to use tools such as pliers, hand hammers, and blades to pull out the positioning pins, but This method is easy to damage the pin holes and pins, which will directly lead to the scrapping of the original parts. The positioning pin can be pulled out by pulling the pull rod, but in order to ensure the assembly accuracy between the parts, the matching between the positioning pin and the pin hole on the part is tight and the number of pins is large, so this method is inconvenient to operate. And time consuming.
Advantages of anti-loose washers 1. Ensure that the clamping force of the connection is still maintained under strong vibration, which is better than fasteners that rely on friction to come from the lock; 2. Prevent the loosening of bolts caused by vibration, which no longer occurs due to fasteners related problems caused by loosening; 3. No special installation work is required, and it is easy to install and disassemble; 4. The temperature changes will not make the connector loose; 5. Durable; 6. Reusable.
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.
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