Surface treatment method of angle steel

Angle steel, also known as angle iron due to its distinct "L"-shaped cross-section, is an essential steel material used in various industries. However, angle steel is susceptible to erosion during use. In humid environments, it is prone to rust, while in industrial settings with numerous chemicals, corrosion can occur. These issues not only affect its appearance but also weaken its performance, shortening its service life. To ensure angle steel maintains its performance in different environments and prolongs its lifespan, surface treatment is crucial. Below are several common and practical surface treatment methods for angle steel.

Union Steel Industry Co., Ltd is professional angle steel manufacturer, for more details, please contact:sales@union-steels.com

1. Hot-Dip Galvanizing

Principle: The angle steel is immersed in molten zinc to form a zinc-iron alloy layer and a pure zinc layer on the surface, providing corrosion protection.
Advantages: The hot-dip galvanized layer offers excellent corrosion resistance, effectively protecting the angle steel from rust in atmospheric conditions, water, and other media, and provides a long service life. The zinc layer has strong adhesion and is not easily detached.
Disadvantages: The hot-dip galvanizing process may affect the size and surface flatness of the angle steel, and it is more expensive.
Application Scenarios: Commonly used in construction, electricity, transportation, and other fields, such as angle steel brackets in building structures, iron towers in transmission lines, etc.

2. Electrogalvanizing

Principle: Electrolytic deposition of a zinc layer is applied to the surface of the angle steel.
Advantages: The electrogalvanized layer is smooth and uniform, and the thinner zinc layer is ideal for applications with high appearance requirements. The electrogalvanizing process is efficient and cost-effective.
Disadvantages: The corrosion resistance of the electrogalvanized layer is inferior to that of hot-dip galvanizing, and it does not perform as well in harsh environments.
Application Scenarios: Typically used in applications where appearance is more important than corrosion resistance, such as in furniture, decoration, and other industries.

3. Painting

Principle: A layer of paint is applied to the surface of the angle steel, creating a protective film that prevents contact with corrosive elements such as air and water.
Advantages: Paint is available in a wide range of colors and can be customized according to needs, providing good aesthetic qualities. The painting process is simple and cost-effective.
Disadvantages: The adhesion and corrosion resistance of paint layers are relatively poor, requiring regular maintenance and reapplication. Paint is prone to peeling and aging when exposed to harsh environments.
Application Scenarios: Suitable for applications with aesthetic requirements but less emphasis on corrosion resistance, such as interior decoration and general mechanical enclosures.

4. Plastic Spraying

Principle: Plastic powder is applied to the angle steel using electrostatic spraying, then baked at high temperatures to form a solid plastic coating.
Advantages: The plastic coating offers good corrosion resistance, wear resistance, and decorative properties. The coating is uniform and resistant to defects like sagging and blistering.
Disadvantages: The plastic spraying process requires high-quality surface preparation and is more expensive. In high-temperature environments, the plastic coating may deform or age.
Application Scenarios: Commonly used for building doors and windows, guardrails, and other applications where both protective performance and aesthetics are important.

5. Phosphating

Principle: A phosphate conversion film is formed on the surface of the angle steel through a chemical reaction to enhance corrosion resistance and improve paint adhesion.
Advantages: The phosphate film improves corrosion resistance, lubricity, wear resistance, and anti-adhesion properties. It also enhances the adhesion of subsequent coatings, extending their durability.
Disadvantages: Phosphated angle steel has a darker appearance, generally gray or black, which may affect the aesthetics. The phosphating process generates wastewater and waste residue, requiring environmental treatment.
Application Scenarios: Commonly used as a pretreatment process in machinery manufacturing, the automotive industry, and other fields before painting or plastic coating to improve coating quality and durability.

Conclusion

There are numerous surface treatment methods for angle steel, each offering distinct advantages. In practical applications, it is essential to consider factors such as the intended use environment, budget, and aesthetic preferences to choose the most suitable treatment method. By doing so, we can maximize the performance, durability, and appearance of angle steel, ensuring it reaches its full potential in various engineering projects.