Machining Nickel Plated Chamfered Socket Head Flat Head Screws Bolts Furniture Screws 3/4

As shown in Figures 1 and 2, Yueluo is an automatic locking screw. From bottom to top, there are screw head 1 with external thread, screw rod and nut 3. The screw rod is a hollow screw rod 2, and the hollow screw There are long holes 7 on both sides of the rod 2, the width of the long hole 7 is smaller than the inner diameter of the hollow screw rod 2, and a spring 4 is arranged in the inner cavity of the hollow screw rod 2, and the spring 4 is not smaller than the hollow screw rod 2 in the free extension state. The upper end of the spring 4 is provided with a plug 5, the distance between the two wings 6 of the plug 5 is greater than the diameter of the nut 3, and the two wings 6 of the plug 5 protrude out of the hollow screw rod 2 through the long hole 7. When using the Yueluo, you only need to compress the spring through the two wings, insert the U-shaped clip after the neutral position is exposed, and then release the two wings, the spring will automatically return and compress the U-shaped clip, which is easy to use, safe and reliable. Claim 7. A self-locking screw, from bottom to top, is a screw head, a screw rod and a nut provided with an external thread, characterized in that the screw rod is a hollow screw rod, and both sides of the hollow screw rod are respectively provided with Long hole, the width of the long hole is smaller than the inner diameter of the hollow screw rod, the inner cavity of the hollow screw rod is provided with a spring, the upper end of the spring is provided with a plug, and the two wings of the plug protrude out of the hollow screw rod through the long hole.

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.

flat washer is a part that is placed between the connected part and the bolt to protect the surface of the connected part from being scratched by the nut and to disperse the pressure of the nut on the connected part. At present, a flat washer in the prior art generally includes a washer body; the washer body has a bolt hole in the middle for a bolt to pass through. Although the flat washer of the above structure has a simple structure, it still has a disadvantage. When the flat washer is cushioned between the connected part and the bolt, the bolt head is usually exposed outside the connection part, so the bolt head is easy to It is damaged under the impact of external force, thus affecting its fixing effect.

Nuts and washers are both small and medium-sized components of the tension reinforcement system, and they are easily lost on the construction site when used separately, which is not conducive to the storage management of turnover materials; 3) During the process of formwork support and removal, they must be installed individually And demolition, thus adding a construction process, affecting the efficiency of construction.

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