Supply nickel-plated cross recessed large flat head screw umbrella head screw big head screw flat tail machine screw

When the countersunk head screws and hexagon socket head bolts are produced by the cold heading process, the original structure of the steel will directly affect the forming ability of the cold heading process. In the process of cold heading, the plastic deformation of the local area can reach 60%-80%, so the steel must have good plasticity. When the chemical composition of the steel is constant, the metallographic structure is the key factor to determine the plasticity. It is generally believed that the coarse flaky pearlite is not conducive to cold heading forming, while the fine spherical pearlite can significantly improve the plastic deformation ability of the steel. For medium carbon steel and medium carbon alloy steel with a large amount of high-strength bolts, spheroidizing (softening) annealing is performed before cold heading, so as to obtain uniform and fine spheroidized pearlite to better meet the actual production needs. For the softening annealing of medium carbon steel wire rods, the heating temperature should be kept above and below the critical point of the steel, and the heating temperature should not be too high, otherwise tertiary cementite will precipitate along the grain boundary, resulting in cold heading cracking. The wire rod of medium carbon alloy steel is annealed by isothermal spheroidization. After heating at AC1+ (20-30%), the furnace is cooled to slightly lower than Ar1, the temperature is about 700 degrees Celsius for an isothermal period, and then the furnace is cooled to about 500 degrees Celsius and air-cooled. The metallographic structure of the steel changes from coarse to fine, from flake to spherical, and the cracking rate of cold heading will be greatly reduced. The general area of softening annealing temperature for 35\45\ML35\SWRCH35K steel is 715-735 degrees Celsius; while the general heating temperature for spheroidizing annealing of SCM435\40Cr\SCR435 steel is 740-770 degrees Celsius, and the isothermal temperature is 680-700 degrees Celsius.

A nut is a nut, a part that is screwed together with a bolt or screw for fastening. A component that must be used in all production and manufacturing machinery is divided into carbon steel, stainless steel, non-ferrous metals (such as copper), etc. several types.

At present, with the development of my country's railway industry, many railway fastener systems involve T-bolts. The structure is shown in Figure 1. The dimensions that need to be inspected are head width A, head length B, and head straight table height. C. The height of the head slope D, the total length of the bolt E, and the major diameter of the bolt F. Due to the irregular shape of these places to be inspected, the measurement is difficult. The measurement of general measuring tools is not only slow, but also difficult to control human errors, resulting in some extreme upper limits and There are disputes and misjudgments about the size of the extreme lower limit when judging qualified and unqualified.

The circlip extrusion and positioning mechanism includes a vertically installed circlip sleeve rod and a linear module controlled by a positioning motor; a plurality of circlips to be installed are sleeved on the surface of the circlip sleeve rod; the surface of the linear module can be Mobile installation quick clamp; the clamping mouth of the quick clamp is a tight top plate; the tight top plate is in contact with the upper circlip and moves up and down with the up and down movement of the circlip sleeve;

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