What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Stainless steel nuts generally have or become loose during use, which mainly depends on the thread. As for the threaded sleeve, it is a new type of threaded fastener, which is a spring-shaped inner and outer thread concentric body precisely machined from stainless steel wire with high-precision diamond cross-section. Of course its performance is also very good. The following are the following methods of loosening stainless steel nuts: 1. On the mechanical parts loaded with metal or non-metallic materials (such as aluminum, magnesium and other light alloy engineering materials), it can form high strength, wear resistance, high precision standard internal thread. Such as applications: high-voltage switchgear, hydraulic machinery, welding equipment |, tobacco machinery, microwave communications, auto parts, air separation equipment, coal machinery, power machinery, textile and chemical fiber machinery, etc.
Classification broadcast product series Product detailed classification Hexagon bolts (1) Hexagon bolts (1) Hexagon full teeth: GB5783/DIN933 (2) Hexagon half teeth; GB5782/DIN931 (3) Class B flange hexagon bolts: GB5787 (4) Joint bolts: GB798/DIN444 (5) Welding bolts for manual welding: GB902 square neck bolts (1) Half round head square neck bolts: GB14/DIN603 (2) Small half round head square neck bolts: GB12 (3) Half round head low square neck bolts: GB801 Remarks: Square neck bolts and carriage bolts Hexagon socket head cap screws (1) Hexagon socket head cap screws: GB70/DIN912 (2) Hexagon socket flat end set screws: BG70/DIN913 (3) Hexagon socket head set screws: GB78/DIN914 ( 4) Countersunk head socket head socket head set screw: GB79/DIN915 (5) Hexagon socket socket head set screw: GB80/DIN916 (6) Hexagon socket head countersunk head screw: DIN7991 (7) Hexagon socket head thin head screw: DIN7984 ( 8) Plug screw: ISO7379 machine screw (1) Slotted cylinder head screw: GB65/DIN84 (2) Slotted pan head screw: GB67/DIN85 (3) Slotted countersunk head screw: GB68/DIN963 (4) Slotted Large flat head screw (5) Cross recessed small pan head screw: GB823 (6) Cross recessed large flat head screw (7) Cross recessed pan head screw: GB818/DIN7985 (8) Cross recessed countersunk head screw: GB819/DIN965 (9 ) Cross recessed countersunk head screw: GB820/DIN966 thread and stud (2) Stud bolt-bm=1d: GB897/DIN938 (3) Stud bolt-bm=1.25d: GB898/DIN939 (4) Stud head Bolt-bm=1.5d: GB899 (5) Stud bolt-bm=2d: GB900 (1) Tooth bar: GB15389/DIN976 (6) Equal length stud: GB901/DIN976
In the prior art, the hardware and the handle are generally assembled and connected by means of rivet riveting; in the process of assembling the hardware and the handle, the prior art adopts manual operation to realize the riveting and assembling process, which is time-consuming and labor-intensive. and low productivity.
Material and process requirements The self-tapping locking screw should be made of high-quality carburized steel cold heading, generally no larger than M12. The finished material should be drawn with a high total reduction rate before cold heading, so that the cold heading must be spheroidized. Annealing, in order to enhance the surface hardness and the toughness of the core, most of them are made of medium and low carbon steel. The chemical composition of the material in the standard is only for guidance. The C content is 0.13%~0.37%, the Mn content is 0.64%~1.71%, and the B content can reach 0.005%. The elements of S, P, Mn and Si in the commonly used steel are generally lower than those of the ordinary bolt steel of the same grade. And the surface quality of the material is strictly controlled to reduce deformation resistance and prevent deformation and cracking. Commonly used grades are 20Mn, 15MnB, SWRCH22A, 1022A and medium carbon steel, medium carbon alloy steel SWRCH35K, SCM435, SCR435, etc. Self-tapping locking screws are threads with an arc-shaped triangular cross-section, so the formulation of cold heading and wire rolling processes, as well as the design and manufacture of cold heading dies and special rolling plates are very important. Self-tapping locking screws require a high-hard surface for cutting and extruding capabilities due to the need for self-tapping low carbon steel. At the same time, there must be sufficient core strength and toughness to prevent twisting and breaking during work. The heat treatment process of this type of screw belongs to shallow carburizing. Regardless of whether it is made of low carbon steel or medium carbon or medium carbon alloy steel, its core hardness must be guaranteed to be within the range of 28~38HRC (9.8 grade) 33~39HRC (10.9 grade) and not less than the minimum tensile load of 930MPa (9.8 grade), 1040MPa (grade 10.9), depending on the material, the minimum tempering temperature is 420℃. In order to ensure that the self-tapping locking screw can be smoothly screwed into the prefabricated cylindrical hole, the end of the screw should be hardened by high-frequency quenching to ensure that at least one to three thread teeth are hardened, and the minimum surface hardness is 45HRC.
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