What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Large, countersunk, and thin rivet nuts can be produced according to different die angles. Then the cold forged rivet nut is degreasing, cleaned and annealed, and then extruded and tapped and surface electroplated. Since the rivet nut is formed by cold extrusion of low carbon steel, it has high mechanical properties. Specifically, the tensile strength of M3 is 250Kg, the shear strength is 140Kg; the tensile strength of M4 is 700Kg, the shear strength is 220Kg; the tensile strength of M5 1100Kg, shear force 380Kg; M6 tensile force 1750Kg, shear force 450Kg; M8 tensile force 2650Kg, shear force 660Kg.
Although there are many types of self-tapping locking screws, they all have the following main characteristics: (1) Generally, they are made of carburized steel (accounting for 99% of the total products). Also available in stainless steel or non-ferrous metals. (2) The product must be heat treated. Carbon steel self-tapping screws must be carburized, and stainless steel self-tapping screws must be solution hardened. In order to make the self-tapping screw meet the mechanical properties and performance required by the standard. (3) The product has high surface hardness and good core toughness. That is, inner softness and outer rigidity. This is a major feature of the performance requirements of self-tapping screws. If the surface hardness is low, it cannot be screwed into the matrix; if the toughness of the core is poor, it will break as soon as it is screwed, and it cannot be used. Therefore, inner softness and outer rigidity are the requirements for self-tapping screws to meet the performance requirements. (4) The surface of the product needs surface protection treatment, generally electroplating treatment. Some product surfaces require phosphate treatment (phosphating). Such as: wall panel self-tapping screws are mostly phosphating. (5) It is produced by cold heading process. It is recommended to use high-speed cold heading machine and high-speed thread rolling machine or high-speed planetary thread rolling machine to ensure product quality. The self-tapping screw produced in this way has a well formed head and high thread quality.
In the fastening connection parts and parts assembly of various equipment and tooling, if the screw and nut anti-loosening treatment is required, there is a contradiction between anti-loosening and tightening or tightening and loosening. For example, the resistance is large when tightening. , or the resistance is large when loosening, or the anti-loosening effect is not good, or the service life is short, and it will be scrapped after 2 to 3 times of use. In a word, all kinds of anti-loosening nuts have the above problems at present. Therefore, it is necessary to utilise a new type of anti-loosening nut with low resistance when tightening or loosening, but with better anti-loosening effect and long service life.
Welding stud is also called welding screw, which belongs to a kind of fastener connected with high strength and rigidity. Welding stud is the abbreviation of cylindrical head welding stud for arc stud welding. Industrial plant construction, highways, railways, bridges, towers, automobiles, energy, transportation facilities, airports, stations, power stations, pipeline supports, lifting machinery and other types of steel structures and other projects.
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