What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
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 order to solve the above-mentioned technical problems, the technical solution adopted by Guangdong Yueluo Hardware Industry Co., Ltd. is: shear rivets, including a mandrel and a deformation sleeve ring sleeved on the mandrel, one end of the deformation sleeve ring is a boss structure, and the It includes an adhesive collar sleeved on the deformation collar, the adhesive collar is a hollow annular sleeve and is filled with adhesive material; one end of the mandrel is a hemispherical head, and the spherical surface of the hemispherical head is outward, The connection between the hemispherical head and the mandrel is a conical connecting section, and the diameter of the conical connecting section gradually decreases from the hemispherical head inward; the mandrel is provided with a stress concentration groove, and the position of the stress concentration groove is close to the deformation The boss structure of the collar.
Stud bolts generally need to be surface treated. There are many types of bolt surface treatments. Generally, electroplating, blackening, oxidation, phosphating, and electroless zinc flake coating are commonly used. However, electroplated fasteners account for a large proportion of the actual use of fasteners. Especially in automobiles, tractors, home appliances, instrumentation, aerospace, communications and other industries and fields are more widely used. However, for threaded fasteners, not only a certain anti-corrosion capability is required in use, but also the interchangeability of threads must be ensured, which can also be called screwability here. In order to meet the dual-use performance of anti-corrosion and interchangeability required by threaded fasteners in use, it is very necessary to formulate special plating standards. GB/T5267.1-2002 [Threaded fastener electroplating layer] standard is one of the national standards fastener surface treatment series of standards, the standard includes: GB/T5267.1-2002 [fastener electroplating layer]; GB/T5267.2-2002 [Electrolytic zinc flake coating for fasteners] Two standards. This standard is equivalent to the international standard ISO4042; 1999 [Threaded fastener electroplating layer]. This standard replaces the GB/T5267-1985 [Threaded Fastener Electroplating Coating] standard.
Convex washers are mainly punched out of iron plates. The shape is generally a flat washer with a hole in the middle. Flat washers are usually thin pieces of various shapes to reduce friction, prevent leakage, isolate, prevent loosening or Dispersing pressure, the rationality of its design structure and the safety during use are very important.
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