Common Surface Treatments for Fully Threaded Studs

2025-12-04 10:53:49

Electro-galvanizing is a method of coating the surface of fully threaded studs with a layer of zinc. Its main advantage lies in its good corrosion resistance. Zinc has strong antioxidation capability and can form a protective film on the stud surface to block moisture and corrosive media. This treatment is relatively low-cost and suitable for general indoor environments, but it is not recommended for highly corrosive environments such as marine environments or areas with high humidity.

Compared with electro-galvanizing, hot-dip galvanizing is a process in which studs are immersed in molten zinc to form a zinc layer. As a result, the zinc layer is typically 5–10 times thicker than that of electro-galvanizing, providing longer-lasting and more reliable corrosion protection. Hot-dip galvanized studs are commonly used in outdoor and harsh environments, such as bridges, docks, and construction sites under highly corrosive conditions.

Oxidation treatment is a technique that forms an oxide film on the metal surface through chemical or electrolytic methods. For steel fully threaded studs, black oxide treatment (also known as blackening) is commonly used to enhance corrosion resistance. This treatment improves surface wear resistance and visual appearance while providing a certain level of corrosion protection. However, its protection capability is inferior to galvanizing and is only suitable for mildly corrosive environments.

Phosphating is a chemical treatment that produces an insoluble phosphate protective film on the metal surface. After phosphating, the surface layer of fully threaded studs effectively improves corrosion and wear resistance. Phosphating is widely used in the automotive industry and machinery manufacturing. It can also serve as a base layer for subsequent painting or coating, improving adhesion and overall coating performance.

Chrome plating provides a more advanced surface treatment solution for fully threaded studs. The chromium layer offers strong corrosion resistance, excellent wear resistance, and an attractive mirror-like appearance. Although chrome plating is more costly, it is widely used in high-end products and mechanical structures with special requirements due to its combination of decorative and functional benefits.