A Comprehensive Guide to Surface Treatments for Metal Construction Accessories: Process Analysis and Industry Insights

The surface treatment of metal construction accessories not only determines the aesthetic appearance of the products but directly impacts their anti-corrosion performance and service life under various working conditions. Based on industry standards and project practices, Zhengzhou Duorui Enterprise provides an in-depth analysis of mainstream surface treatment technologies, offering parameter-driven selection guidance for engineering procurement and design.

Core Galvanizing Process Parameters

Zinc-based coatings serve as the fundamental anti-corrosion barrier for construction hardware. The process selection depends strictly on the required zinc thickness and assembly tolerances.

• Hot-Dip Galvanizing (HDG): Zinc thickness generally ranges from 35-200μm, complying with ISO 1461 or ASTM A153 standards. It forms a metallurgical bond with the substrate, providing exceptional physical wear resistance. It is highly suitable for heavy-corrosion outdoor environments, such as scaffold jacks, formwork nuts, and large structural steel components.

  

• Electro-Galvanizing (EG): The zinc layer is precisely controlled within 5-15μm. The primary advantage of this process is its high coating uniformity, ensuring that precise thread tolerances are not compromised. It is widely used for high-precision assembly parts like formwork tie nuts and scaffold couplers.

• Mechanical Galvanizing: With a standard thickness of 5-25μm (complying with ASTM B695), this room-temperature process inherently eliminates the risk of “hydrogen embrittlement” in high-strength steel. It performs exceptionally well for construction nails and high-strength fasteners.

• Sherardizing: Yielding a thickness of approximately 100μm (per BS EN 13811), this thermal diffusion process creates a dense uniform coating without edge build-up. It is particularly suitable for complex-shaped workpieces, pipe locks, and embedded metal parts.

  

High-Performance Anti-Corrosion and Coating Technologies

For severe industrial or marine environments, advanced alloy coatings and electrochemical processes offer reliable solutions.

• Dacromet (Zinc Flake Coating): Despite a very thin coating layer (typically 5-10μm), Dacromet can withstand 500 to 1000 hours in Neutral Salt Spray (NSS) testing. Featuring zero hydrogen embrittlement risk, it is ideal for high-strength bolts and connectors requiring tight dimensional tolerances.

• Electrophoresis (E-coating): Providing a uniformly controlled film thickness (usually 15-25μm), E-coating boasts excellent edge coverage and adhesion. It is often utilized as a high-performance primer for complex structural hardware.

  

Aesthetic and Barrier Protections: Painting and Powder Coating

When projects mandate specific color identification or UV resistance, organic barrier coatings become essential.

• Powder Coating (Plastic Spraying): Coating thickness typically ranges between 60-120μm. Applied electrostatically and cured under high heat, it delivers excellent weathering and UV resistance, making it optimal for outdoor architectural decorative accessories.

• Painting and Spraying: Suitable for oversized components. By combining epoxy zinc-rich primers with polyurethane topcoats, customized film thicknesses (100-300μm+) can be achieved to combat heavy industrial corrosion.

  

Zhengzhou Duorui Enterprise Selection Recommendations

In practical applications, the choice of surface treatment must balance the environmental corrosivity category, mechanical property preservation, and cost-effectiveness. Zhengzhou Duorui Enterprise advises clients to explicitly specify the required coating thickness and target international standards during the design phase.

For more detailed product specifications and standardized metal construction accessories, please visit duoruimaterials.com. Relying on our extensive manufacturing experience, we are committed to providing highly reliable, parameter-backed surface treatment solutions for your projects.