Prevention Guide Of Galvanic Corrosion For Self-clinching Fasteners, Material Matching Specification Between Clinch Parts And Different Sheet Metals

Prevention Guide Of Galvanic Corrosion For Self-clinching Fasteners, Material Matching Specification Between Clinch Parts And Different Sheet Metals

Many sheet metal engineers ignore contact corrosion of dissimilar metals. Carbon steel clinch parts pressed into aluminum plates or stainless clinch nuts installed on galvanized carbon steel cabinets form galvanic cell reaction under humid and rainy conditions, leading to sheet perforation. Coastal outdoor energy storage cabinets and 5G communication enclosures frequently suffer such failures. Ordinary painting cannot eliminate corrosion fundamentally.

1. Matching Table Of Clinch Fastener Material For Common Sheet Metals

2. Three Effective Measures Against Galvanic Corrosion

1. Same-material priority: Select clinch parts made of identical material as base sheet to minimize potential difference; 2. Insulation isolation: If material replacement is impossible, install insulating gaskets on flange surface to cut galvanic cell circuit; 3. Surface passivation sealing: Strengthen passivation for stainless clinch parts, adopt thick coating for carbon steel parts to reduce surface conductivity and slow corrosion.

3. Common Design Mistakes And Rectification Plans

1. Carbon steel clinch nuts on aluminum sheets: No obvious defects at the beginning, aluminum pitting perforation appears within 6~12 months in coastal areas. Replace with CLA aluminum clinch parts; 2. Carbon steel clinch parts for stainless steel cabinets: Carbon steel rust quickly and pollute stainless surface, switch to CLS stainless series; 3. Only rely on cabinet painting for anti-rust: Paint film cracks at pressed position, moisture penetrates and triggers corrosion. Material matching is mandatory; 4. Finished clinching without replacement option: Fill anti-corrosion sealant on nut flange to isolate moisture and salt.