The surface treatment of shield segment bolts is an important part to ensure good corrosion resistance and extend service life during use. Common surface treatment methods for shield segment bolts are mainly as follows:
Hot-dip galvanizing (hot-dip galvanizing):
This is one of the most commonly used surface treatment methods. By immersing the bolt in molten zinc liquid, a layer of zinc is attached to the surface of the bolt. This zinc layer can effectively isolate the bolt from the contact with the corrosive medium, thereby playing an anti-corrosion role. Bolts treated with hot-dip galvanizing not only have good corrosion resistance, but also have beautiful appearance and moderate cost.
Dacromet (zinc-based chromate):
Dacromet treatment is a metal surface treatment technology that achieves anti-corrosion by coating a layer of zinc-based chromate film on the surface of the bolt. This treatment method has higher corrosion resistance than hot-dip galvanizing, especially in harsh environments (such as high humidity, high salt spray, etc.). However, the cost of Dacromet treatment is also relatively high.
Powder sherardizing:
Powder sherardizing is a method of combining zinc powder with the surface of the bolt using powder metallurgy technology. Through high temperature treatment, zinc powder and the bolt surface form a dense zinc-iron alloy layer, thereby improving the corrosion resistance of the bolt. Powder shearing treatment has the advantages of environmental protection and high efficiency, but its application range may be limited compared with the first two treatment methods.
Multi-component composite powder shearing:
This is an upgrade or variant of powder shearing technology. By adding other elements (such as aluminum, chromium, etc.) during the shearing process, a multi-component composite alloy layer is formed to further improve the corrosion resistance and comprehensive performance of the bolt. This treatment method has significant advantages in specific applications.
In summary, there are many ways to treat the surface of shield segment bolts, each of which has its own unique advantages and scope of application. When choosing a surface treatment method, it is necessary to comprehensively consider factors such as specific engineering requirements, environmental conditions and costs. At the same time, it is also necessary to pay attention to selecting manufacturers with corresponding qualifications and experience for surface treatment processing to ensure the quality and effect of the treatment.
