Production of stainless steel large flat head screw large flat head cross machine screw mushroom head 1/2-13

At present, in the power industry, for the fixing of terminals, most of the terminals are directly locked to the fixing screws using U-shaped clips. However, since the contact surface often cannot reach the level of flatness, it will cause difficulties in locking, and it will take a long time. Easy to loose and fall off. Although the use of spring clips is effective, due to the influence of its own width, the use of spring clips is not very extensive. Contents of the utility model The purpose of Yueluo Guangdong Yueluo Hardware Industry Co., Ltd. is to provide an automatic locking screw for fixing the U-shaped clip. In order to achieve the above purpose, Yueluo adopts the following technical solutions: an automatic locking screw. From bottom to top, there are screw head, screw rod and nut with external thread. The screw rod is a hollow screw rod, and the hollow screw rod is on both sides. Long holes are respectively provided, the width of the long holes is smaller than the inner diameter of the hollow screw rod, a spring is arranged in the inner cavity of the hollow screw rod, the upper end of the spring is provided with a plug, and the two wings of the plug protrude out of the hollow screw rod through the long hole. The spring described by Yueluo is not less than the length of the hollow screw rod in the free extension state. The distance between the two wings of the plug described by Yueluo is greater than the diameter of the nut. Yueluo adopts Guangdong Yueluo Hardware Industry Co., Ltd., which can easily realize the automatic locking of the U-shaped clamp, and can be adjusted according to the thickness of the U-shaped clamp to ensure the close contact between the U-shaped clamp and the connecting screw.

High-strength fasteners must be quenched and tempered according to technical requirements. The purpose of heat treatment and tempering is to improve the comprehensive mechanical properties of fasteners to meet the specified tensile strength value and yield ratio of the product. The heat treatment process has a crucial impact on high-strength fasteners, especially its intrinsic quality. Therefore, in order to produce high-quality high-strength fasteners, advanced heat treatment technology and equipment must be available. Due to the large production volume and low price of high-strength bolts, and the threaded part is a relatively fine and relatively precise structure, the heat treatment equipment is required to have large production capacity, high degree of automation, and good heat treatment quality. Since the 1990s, the continuous heat treatment production line with protective atmosphere has dominated, and the shock bottom type and mesh belt furnace are especially suitable for heat treatment and tempering of small and medium-sized fasteners. In addition to the good sealing performance of the furnace, the quenching and tempering line also has advanced computer control of atmosphere, temperature and process parameters, equipment failure alarm and display functions. High-strength fasteners are automatically controlled and operated from feeding-cleaning-heating-quenching-cleaning-tempering-coloring to offline, which effectively ensures the quality of heat treatment. The decarburization of the thread will cause the fastener to trip before the resistance required by the mechanical properties is reached, which will cause the failure of the threaded fastener and shorten the service life. Due to the decarburization of the raw material, if the annealing is improper, the decarburized layer of the raw material will be deepened. In the process of quenching and tempering heat treatment, some oxidizing gas is generally brought in from outside the furnace. The rust of the bar wire or the residue on the surface of the wire rod after cold drawing will also decompose after being heated in the furnace, and some oxidizing gases will be generated by the reaction. For example, the surface rust of steel wire, which is composed of iron carbonate and hydroxide, will be decomposed into CO₂ and H₂O after heating, thus aggravating decarburization. Studies have shown that the degree of decarburization of medium carbon alloy steel is more serious than that of carbon steel, and the fastest decarburization temperature is between 700 and 800 degrees Celsius. Because the attachments on the surface of the steel wire decompose and synthesize carbon dioxide and water very quickly under certain conditions, if the furnace gas of the continuous mesh belt furnace is not properly controlled, it will also cause excessive decarburization of the screw. When the high-strength bolt is formed by cold heading, the raw material and the annealed decarburized layer not only still exist, but also are extruded to the top of the thread. For the surface of the fastener that needs to be quenched, the required hardness cannot be obtained. Its mechanical properties (especially strength and wear resistance) decreased. In addition, the surface of the steel wire is decarburized, and the surface layer and the internal structure have different expansion coefficients, and surface cracks may occur during quenching. For this reason, during quenching and heating, the top of the thread should be protected from decarburization, and the fasteners whose raw materials have been decarburized should be properly carbonized, and the advantages of the protective atmosphere in the mesh belt furnace should be adjusted to the original carbon-coated parts. The carbon content is basically the same, so that the decarburized fasteners are slowly restored to the original carbon content. The carbon potential is preferably set at 0.42% - 0.48%. The carbon coating temperature is the same as the quenching heating, and cannot be carried out at high temperatures , so as to avoid coarse grains and affect mechanical properties. The quality problems that may occur in the process of quenching and tempering of fasteners mainly include: insufficient hardness in the quenched state; uneven hardness in the quenched state; excessive quenching deformation; quenching cracking. Such problems in the field are often related to raw materials, quenching heating and quenching cooling. Correctly formulating the heat treatment process and standardizing the production operation process can often avoid such quality accidents.

Hexagon socket head cap screws are indispensable industrial necessities in daily life and have important tasks in industry. But ordinary hexagon socket head cap screws must be installed and disassembled with special tools. For ordinary users, some simple disassembly and maintenance work are often unable to be handled due to lack of tools.

hand screw is a screw with a plastic head, and the user fixes the hand screw by turning the plastic head by hand. At present, a hand-tight screw is disclosed in the market publication number CN202203253U, which includes a plastic head and a screw rod, the plastic head and the screw rod are connected together, and the height of the plastic head is higher than that of an ordinary screw, and the height is 7cm. The screw of the hand screw is fixed in the plastic head by glue. After a period of use, the aging of the glue leads to the loosening of the screw and the plastic head. When the plastic head is stressed, the screw rod comes out of the plastic head, which affects the normal use of the hand screw.

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