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.
In the past production, gaskets were generally obtained from two channels: first, standard gaskets were mostly purchased from the market, and the cost was high; non-standard gaskets, due to the small demand, required separate tooling and molds, which were expensive and long production cycle. It is difficult to purchase; Second, the plate is purchased by the enterprise, and then the washer is formed by the automatic cutting machine. Because the cut nodules and cut marks produced by flame cutting do not meet the requirements for use, the inner and outer diameters need to be reserved 2 ~3mm machining allowance, and then finish the outer diameter and inner diameter by lathe.
Copper nuts, also known as embedded nuts and embedded copper nuts or plastic embedded nuts, are divided into hot melt copper nuts, hot pressed copper nuts, embedded copper nuts and ultrasonic copper nuts according to different methods of use. This product is widely used in mobile phones. Shell / Pen meter shell / injection molding / insert of plastic parts, used as an internal thread. Generally embossed on the outer circle. To prevent sliding.
Swimming self-locking nut GJB 125.1~125.6-86 The double-ear sealing swimming self-locking nut is composed of four parts: sealing cover, self-locking nut, pressure ring and sealing ring. It has compact structure and reliable sealing, and is suitable for products whose working pressure is not more than 2atm, working medium is gasoline, kerosene, water or air, and the operating temperature is -50~100℃. However, it has certain difficulties in the manufacturing process and air tightness test.
An elastic cylindrical pin assembling device, the assembling device includes an adapter handle, a punching needle, an elastic piece, a fixed sleeve and a telescopic sleeve, the adapter handle and the fixed sleeve are fixedly connected, and the punching needle is inserted into the adapter handle and fixed Inside the sleeve and its upper end is pressed against the adapter handle, the lower end of the punch needle is also inserted into the fixed sleeve and moves relative to the fixed sleeve in the up and down direction when the adapter handle pushes it to move up and down, the fixed sleeve A reset spring is also set between the punch and the punch, the lower end of the fixing sleeve has an insertion hole for the elastic cylinder pin, that is, a working cavity, and the lower end of the punch needle is also provided with a push fit for the upper end of the elastic cylinder pin. the positioning boss. When the elastic cylindrical pin assembling device is used, after assembling an elastic cylindrical pin, the elastic cylindrical pin needs to be re-installed into the fixed sleeve, which cannot realize continuous assembly and has low assembly efficiency.
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