Troubleshooting Common Issues with Structural Aluminum

Structural aluminum, renowned for its strength, lightweight, and corrosion resistance, serves as the backbone of countless architectural marvels. However, like any material, it is not immune to occasional glitches. Identifying and addressing these issues swiftly ensures the longevity and integrity of your aluminum structures.

1. Galvanic Corrosion

When dissimilar metals, such as aluminum and steel, are in direct contact in the presence of an electrolyte (e.g., water), galvanic corrosion may occur. This electrochemical process leads to the preferential corrosion of aluminum. To prevent this, use non-conductive materials (e.g., plastic sleeves) as barriers between the metals.

2. Stress Corrosion Cracking

Stress corrosion cracking (SCC) occurs when aluminum is exposed to both tensile stress and a corrosive environment. Factors contributing to SCC include residual stresses during fabrication, high operating temperatures, and chloride ions. To mitigate SCC, minimize residual stresses, avoid sustained tensile loads, and implement protective coatings.

3. Pitting Corrosion

Pitting corrosion, a localized form of corrosion, manifests as small, deep pits on the aluminum surface. It primarily occurs in environments with high chloride concentrations. To prevent pitting, use corrosion-resistant alloys, apply protective coatings, and optimize drainage to minimize exposure to moisture.

4. Intergranular Corrosion

In certain alloys, intergranular corrosion (IGC) can occur when the material is exposed to elevated temperatures for extended periods. This corrosion attacks grain boundaries, weakening the metal. To prevent IGC, use alloys with low susceptibility, ensure proper heat treatment, and maintain operating temperatures below critical thresholds.

5. Fretting Corrosion

Fretting corrosion occurs when two aluminum surfaces experience minimal relative motion under load. This wear-related corrosion can lead to material loss and surface damage. To mitigate fretting, use surface treatments (e.g., anodizing), apply lubricants, and design components to minimize contact pressure.

By understanding and addressing these common issues with structural aluminum, you can ensure the reliability and longevity of your structures. Proactive maintenance, early detection, and swift corrective actions will safeguard your investments and prevent potential failures.