What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Bolt material: 18Cr2Ni4W, 25Cr2MoV steel; bolt specification: M27～M48. Because this kind of steel is easy to form a passivation film on the surface, and this passivation film will make the bolt unable to obtain a good adhesion chemical nickel phosphorus layer, so special pretreatment measures must be taken to remove the film first, and measures should be taken To prevent its regeneration, it is possible to ensure a good bonding force between the plated coating and the substrate. At the same time, due to the large geometric size of the bolt, it increases the difficulty of nickel-phosphorus plating treatment and quality inspection of the process.
Guangdong Yueluo Hardware Industry Co., Ltd. discloses a through-hole mounting nut, which includes a hexagonal portion and a cylindrical portion, a threaded hole is arranged between the hexagonal portion and the cylindrical portion, and the cylindrical portion is provided with a threaded hole. Two grooves, each of the two sides of the groove has a convex side, and the upper surface of the side is provided with a convex point; the advantage is that the two sides are squeezed by the bolt, Or after the hammer is struck, it will bend to both sides, and it can be fastened to both sides of the screw hole of the sheet metal without welding.
Gaskets are primarily used to protect the bearing surfaces of the coupled pieces. Bolts, nuts, etc. are mostly made of medium carbon steel, and alloy steel is also used. When there are requirements for anti-corrosion or electrical conductivity, copper, copper alloy and other non-ferrous metals can also be used. The standards of China and many countries stipulate that threaded joints are graded according to their mechanical properties, and the grade code is marked on the fastener. The rivet is made of steel, aluminum alloy or copper alloy, etc., and the head has various shapes to meet the needs of different rivet seams.
Countersunk head, half countersunk head, 1200 countersunk head, half countersunk head rivets are mainly used for riveting occasions where the surface needs to be smooth and the load is not large. Flat head rivets are used for riveting occasions subject to general loads. Flat head and flat head rivets are mainly used for riveting of metal sheets or non-metallic materials such as leather, canvas and wood. Large flat head rivets are mainly used for riveting of non-metallic materials. Semi-hollow rivets are mainly used for riveting occasions with little load. Headless rivets are mainly used for riveting of non-metallic materials. Hollow rivets are light in weight and weak in head, and are used for riveting of non-metallic materials with little load. Tubular rivets are used for unloaded riveting of non-metallic materials. Nameplate rivets are mainly used for riveting nameplates on machines and equipment.
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