For a long time, the rivets used in general riveting, especially the ordinary rivets and bolts and other fasteners commonly used in steel structures such as vehicles and bridges, have low connection reliability, especially under alternating load and impact conditions. Looseness is easy to occur, the maintenance cycle is short, and the maintenance cost is high in the later period, which cannot meet the requirements of railway freight.
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.
Welding stud is also called welding screw, which belongs to a kind of fastener connected with high strength and rigidity. Welding stud is the abbreviation of cylindrical head welding stud for arc stud welding. Industrial plant construction, highways, railways, bridges, towers, automobiles, energy, transportation facilities, airports, stations, power stations, pipeline supports, lifting machinery and other types of steel structures and other projects.
The classification of the second combination screw is divided according to the material of the screw wire and the hardness index of the screw wire. Generally, the two combination screws are divided into stainless steel and iron, and stainless steel is divided into stainless steel 201, stainless steel 304 and stainless steel 316. Iron is divided into three types: low carbon steel, medium carbon steel, and high carbon steel. Carbon steel combination screws refer to iron combination screws. Generally, iron combination screws are classified into grades 4.8, 8.8, 10.9, and 12.9. But in the market, the combination screws of grade 10.9 and grade 12.9 are rarely used, so we won't talk about it here. And the two combination screws on the market are more commonly used combination screws of grade 4.8 and 8.8. 4.8 grade combination screws are generally made of 1010A screw wire rods. After the screw wire rods are beaten into screws, they are combined with spring flat washers. After production, this 4.8 grade combination screw does not need to be hardened. Its hardness can reach 4.8. The 8.8 grade combination screw is generally made of 10B21 screw wire. After the screw wire is punched into a screw, it is equipped with a spring washer and a flat washer, and the three pieces can be combined and rubbed by an automatic spring-flat washer machine. Fasten the spring-flat washer combination on the screw, and the spring-flat washer will not fall off. After the combination screw is produced, it needs to be hardened to make the hardness reach 8.8. After the hardness reaches 8.8, we need to take it for electroplating. In order to prevent hydrogen embrittlement of the spring washer in the 8.8-level combination screw with added hardness, it is easy to break. In this way, it is necessary to carry out hydrogen removal treatment on the hardened combined screws, and the electroplating can only be done after the hydrogen removal.
It can be seen that the above processing method can only be used to process a relatively simple retaining ring (that is, only a ring body, which cannot be cut or punched), and the outer surface of the processed retaining ring still cannot be guaranteed to be completely flat.
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