What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The drawing process has two purposes, one is to modify the size of the raw materials; the other is to obtain basic mechanical properties of the fasteners through deformation and strengthening. For medium carbon steel, medium carbon alloy steel also has another purpose, that is, to make the wire rod. The flaky cementite obtained after controlled cooling is cracked as much as possible during the drawing process to prepare for the subsequent spheroidization (softening) annealing to obtain granular cementite. However, some manufacturers arbitrarily reduce the drawing in order to reduce costs. The excessive reduction rate increases the work hardening tendency of the wire rod, which directly affects the cold heading performance of the wire rod. If the distribution of the reduction ratio of each pass is not appropriate, it will also cause torsional cracks in the wire rod during the drawing process. In addition, if the lubrication is not good during the drawing process, it can also cause regular transverse cracks in the cold drawn wire rod. The tangential direction of the wire rod and the wire drawing die is not concentric at the same time when the wire rod is rolled out of the die, which will cause the wear of the unilateral hole pattern of the wire drawing die to aggravate, make the inner hole out of round, and cause uneven drawing deformation in the circumferential direction of the wire. The roundness of the steel wire is out of tolerance, and the cross-sectional stress of the steel wire is not uniform during the cold heading process, which affects the cold heading pass rate. During the drawing process of the wire rod, the excessive surface reduction ratio will deteriorate the surface quality of the steel wire, while the too low surface reduction ratio is not conducive to the crushing of the flaky cementite, and it is difficult to obtain as much granular cementite as possible. , that is, the spheroidization rate of cementite is low, which is extremely unfavorable to the cold heading performance of the steel wire. For the bar and wire rod produced by the drawing method, the partial surface reduction rate is directly controlled within the range of 10%-15%.
As the most common hardware, screws and nuts are widely used in construction and machinery fields. However, existing screws and nuts are easily corroded to varying degrees in the natural environment, especially the threads on screws and nuts are corroded After that, the whole screw and nut are useless, and people have to discard them, which will inevitably lead to a lot of waste of resources.
Generally, we have to divide the fine thread nut and the coarse thread nut first, but in fact, no matter what kind of fine thread, coarse thread, their specifications are the same, their specifications are M3, M4, M5, M6, M8, M10, etc. . But there is another kind of hexagonal nut, which is divided into English and American, which is only a different national standard. Made in China, it is called the national standard hexagon nut
pressure riveting nut pressure riveting tool Yueluo relates to a tool, specifically a pressure riveting nut pressure riveting tool. [Background Art] In order to quickly press riveting nuts, and to quickly switch press rivet nuts of different specifications and properties, and to ensure the press riveting strength between the press riveting nut and the piece during the press riveting process, a kind of Press riveting tooling. In order to overcome the deficiencies of the prior art, Yueluo provides a pressure riveting tool that can improve the strength of the pressure riveting and can switch the pressure riveting nut of different specifications and properties.
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