What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The process of removing iron oxide plate from cold heading steel wire rod is stripping and dephosphorization. There are two methods: mechanical dephosphorization and chemical pickling. Replacing the chemical pickling process of wire rod with mechanical phosphorus removal not only improves productivity, but also reduces environmental pollution. This phosphorus removal process includes bending method (the round wheel with triangular grooves is commonly used to repeatedly bend the wire rod), spray nine method, etc. The phosphorus removal effect is good, but the residual iron and phosphorus cannot be removed (the removal rate of iron oxide scale is 97%) ), especially when the iron oxide scale is very sticky, therefore, mechanical phosphorus removal is affected by iron scale thickness, structure and stress state. Carbon steel wire rods used for low strength fasteners (less than or equal to 6.8) High-strength bolts (greater than or equal to grade 8.8) use wire rods to remove all iron oxide scales after mechanical dephosphorization, and then go through a chemical pickling process for compound dephosphorization. For low carbon steel wire rods, the iron sheets left by mechanical dephosphorization are likely to cause uneven wear of grain draft. When the grain draft hole adheres to the iron sheet when the wire rod rubs against the external temperature, the surface of the wire rod produces longitudinal grain marks. More than 95% are caused by scratches on the surface of the steel wire during the drawing process. Therefore, the mechanical phosphorus removal method is not suitable for high-speed drawing.
Screw, some people call it screw [Screw] (screw), screw (screw rod). In fact, the screw is a general term, and the screw and the screw rod are different from each other. Screws are generally called wood screws to fasten wooden and plastic parts. The screw rod is a machine screw (machine screw), which is the kind of flat head at the front end. The pitch is small and uniform. It is generally used to fasten metal and machine parts. With the development of society, the materials for making screws are also various, and the functions of screws are becoming more and more diverse.
Gears, mechanical components with teeth on the rim that can continuously mesh to transmit motion and power, are mechanical parts with teeth that can mesh with each other. The gears used in industry are generally made of steel. The commonly used steels are quenched and tempered steel, hardened steel, carburized and quenched steel and nitrided steel. The strength of cast steel is slightly lower than that of forged steel, and it is often used in Larger-sized gears; gray cast iron has poor mechanical properties and can be used in light-load open gear transmissions; ductile iron can partially replace steel gears; plastic gears are mostly used in places where light loads and low noise are required, and are matched with them The gears are generally made of steel gears with good thermal conductivity.
In order to achieve the above purpose, Guangdong Yueluo Hardware Industry Co., Ltd. provides the following technical solution: a square nut, including a nut body, the nut body is in the shape of a cube, the side length is 7.6mm, the height is 2.4mm, and the nut body is up and down. Both ends are respectively provided with a circular protrusion and a circular protrusion with a height of 0.25mm, the circular protrusion and the circular protrusion are respectively tangent to the upper and lower surfaces of the nut body which are square, and the circular protrusion and the circular protrusion are respectively tangent to the square upper and lower surfaces of the nut body. The protrusion and the circular protrusion are provided with a through hole in the middle and penetrate through the nut body. The opening of the through hole is provided with a chamfer of 30°, and the inner wall of the through hole is provided with a thread. There are several strip-shaped protrusions from the circumference inward to the opening of the through hole, and a number of strip-shaped grooves are arranged from the opening of the through hole outward to the circumference of the circular protrusion. There is a chamfer of 15° extending outward to the prism of the nut body.
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