Heat Dip Galvanizing for Bolt Fasteners Surface Treatment

Bolts play a crucial role as fasteners in various engineering applications, and their surface treatment directly affects their corrosion resistance and overall performance. Among them, hot-dip galvanizing is a common and effective treatment method, providing good corrosion protection for fasteners.

Hot-dip galvanizing bolts' unique characteristics

Hot-dip galvanizing is a surface treatment method that involves immersing bolts in a liquid metal zinc or other alloy with a lower melting point. This method is not only cost-effective, but also forms a good corrosion-resistant coating on the fasteners. Widely used in electronic and electrical products, its advantages are mainly reflected in the following aspects:

• Good corrosion resistance: Hot-dip galvanizing provides bolts with a thicker coating, effectively improving corrosion resistance and enabling them to perform well in harsh environments.

• Superior coating adhesion: The good adhesion of the coating allows the bolts to undergo appropriate forming, welding, painting, and other processing after hot-dip galvanizing, increasing their versatility and flexibility.

Therefore, the bolt fastener industry still uses the hot-dip galvanizing process for production.

Differences and similarities between zinc plating and hot-dip galvanizing bolts

Hot-dip galvanizing and zinc plating are two common bolt surface treatment methods, and they have some differences in corrosion resistance and applicable environments. Zinc plating involves electrochemically depositing a thin layer of zinc on the surface of the bolt, while hot-dip galvanizing involves immersing the bolt in liquid metal zinc to form a thicker coating.

In principle, the hot-dip galvanized layer is formed by zinc in the liquid state, with three steps: the formation of a zinc-iron alloy phase layer, a zinc-iron interdiffusion layer, and the outer zinc layer. This gives it the characteristics of a thick and dense pure zinc layer and a zinc-iron alloy layer.

Processing characteristics of hot-dip galvanizing bolts

• Good corrosion protection: With a thick and dense pure zinc layer, it avoids direct contact between the steel substrate and the corrosive solution, providing effective protection.

• Strong corrosion resistance: With a zinc-iron alloy layer, it performs well in marine salt spray and industrial atmospheres, demonstrating excellent corrosion resistance.

• Strong wear resistance: The alloy layer is tightly combined, exhibiting strong wear resistance and suitable for various complex environments.

• Good cold working performance: The fasteners after hot-dip galvanizing can undergo various forming processes such as cold stamping, rolling, drawing, and bending without damaging the coating.

• Improved mechanical properties: Similar to annealing, it helps improve the mechanical properties of the steel substrate and reduce stress during welding.

In practical applications, the bright and aesthetic appearance of hot-dip galvanizing makes it an ideal choice for fastener surface treatment, and its pure zinc layer has good ductility, increasing its applicability.

Overall, the surface treatment of hot-dip galvanized bolts not only enhances the appearance quality of the fasteners but also ensures their long-term stability in various harsh environments.