What is the Important Process of Fastener Bolt Manufacturing?

 As a Railway Fastening System Exporter, let me share with you. In the manufacturing process of fastener bolts, process technology is a very important link. For example, the order of fastener bolt process technology will affect the manufacturing quality of fastener bolts. The following Zhongyu standard parts network is based on fasteners The understanding of bolt knowledge, to share the important process analysis of fastener bolt manufacturing.

Rail Anchor Bolt

Rail Anchor Bolt

1. Upsetting bolt head

The cold heading process is the preferred process for the head forming of fasteners. The cold heading process has the characteristics of high productivity, high material utilization, high surface quality and high internal quality. When the steel rod is cut to the required length, the head can be headed. , The head can be cold formed or hot formed. Generally, the smaller bolts are formed by cold heading, and the larger bolts are formed by hot heading.

The forged bolt head has continuous metal fiber, high strength and better fatigue resistance.

2. Heat treatment process

Heat treatment is one of the important processes in the manufacture of high-strength bolts. Its purpose is to improve the comprehensive mechanical properties of fasteners. The heat treatment process has a very important influence on the internal quality of fasteners, especially high-strength bolts.

With the development of the times, the continuous heat treatment production line with protective effect after the 1990s has occupied a dominant position. In addition to its excellent sealing performance, the device can also accurately control temperature and process parameters through a computer, and has equipment failure alarm and display functions. During the whole process of quenching and tempering heat treatment, some oxidizing gas will be generated outside the furnace. Through a series of chemical changes and corrosion on the surface of high-strength bolts, high-strength bolt materials will decarburize themselves. According to technical personnel, the decarburization of medium-carbon alloy steel is more serious than that of carbon steel, and the fastest decarburization temperature is between 700 and 800 ℃.

Decarburization is a failure factor that needs to be prevented in the heat-care stage of bolts. Decarburization will cause local strength reduction. When the bolt is stressed, it is easy to produce micro-cracks and then develop into fatigue failure.

Increasing carbon on the thread surface will increase the strength and decrease the plasticity, leading to delayed cracks or fractures. To

Poor gas control will also cause the screw to decarbonize very poorly. In the process of cold heading of high-strength bolts, the annealing decarburization layer of the raw material not only exists, but also is extruded to the top of the threads of the high-strength bolts. At this time, the surface of the high-strength bolt that needs to be quenched does not need the pre-designed hardness, and the mechanical properties of the high-strength bolt will be greatly reduced.

Our company also has Rail Anchor Bolt on sale, welcome to contact us.


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