Surface Treatment Process and Corrosion Resistance of Spring Clips
- What are the common surface treatment processes for elastic clips?
They mainly include galvanizing treatment, including hot-dip galvanizing (zinc layer thickness 80-120μm) and electro-galvanizing (zinc layer thickness 10-30μm), with hot-dip galvanizing having better anti-corrosion effect; phosphating treatment, forming a phosphate film on the surface to enhance coating adhesion, often used as pre-treatment before painting; Dacromet treatment, forming a protective film through zinc-chromium coating, with salt spray resistance of more than 500 hours, suitable for humid environments.
- What are the differences in anti-corrosion effects of different surface treatment processes?
Hot-dip galvanized elastic clips can be used for 15-20 years in ordinary atmospheric environments and 10-15 years in coastal humid environments; electro-galvanized elastic clips have a shorter service life, 5-8 years in ordinary environments and 3-5 years in humid environments; Dacromet-treated elastic clips have a service life 1.5-2 times that of hot-dip galvanized ones in salt spray environments, suitable for high-corrosion areas such as chemical industry zones and coastal areas.
- Does surface treatment have an impact on the mechanical properties of elastic clips?
Hot-dip galvanizing will slightly reduce the surface hardness of elastic clips (about 5%-10%), but has little impact on overall elasticity, with the clamping force change not exceeding 3%; phosphating treatment has no obvious impact on mechanical properties, but can reduce wear when elastic clips contact rails; Dacromet treatment will form a 0.01-0.03mm coating on the surface of elastic clips, which has minimal impact on dimensional accuracy and does not affect assembly.
- How to evaluate the quality of elastic clip surface treatment?
Conduct salt spray tests. Hot-dip galvanized elastic clips must pass 480 hours of salt spray testing without red rust, and Dacromet-treated ones must pass 1000 hours of testing; check the coating thickness. The thickness deviation of hot-dip galvanized layers does not exceed ±10μm, and that of electro-galvanized layers does not exceed ±5μm; observe the surface state, with no missing plating, blistering, or peeling, and the coating is uniform and smooth.
- How to select surface treatment processes for elastic clips in different environments?
In dry inland areas, electro-galvanizing or phosphating + painting can be selected to balance cost and anti-corrosion needs; in humid and rainy areas, hot-dip galvanizing is preferred; in high-corrosion environments such as coastal areas and chemical industry zones, Dacromet treatment or hot-dip galvanizing + sealing paint must be used to ensure the service life of elastic clips in harsh environments.