# Aluminum vs Steel rivets/fasteners in a high vibration environment

What are the relative pros and cons between aluminum and steel fasteners when riveting together sheet aluminum (50XX or 60XX) when high amounts of vibration are anticipated? Assuming that the usual guidelines for sheet thickness, hole size and separation are followed, which metal would be the better choice? I don't anticipate atmospheric corrosion to be an issue.

• You will experience galvanic corrosion between a steel rivet and aluminum sheet. Consider stainless steel rivets if aluminum rivets cannot handle the loads. May 11 '16 at 1:54
• @GisMofx I found this link of galvanic corrosion: engineersedge.com/galvanic_capatability.htm May 11 '16 at 11:21
• here's a discussion on a related topic finishing.com/271/67.shtml if you're worried about corrosion at all, use aluminum. Remember, plenty of aircraft are riveted together with aluminum rivets. May 11 '16 at 11:26

Steel is better than stainless steel, with the same kind of aluminum being even better; as far as corrosion is concerned. The difference between steel and stainless for strength won't matter as much for rivets as the potential for corrosion.

See Wikipedia's anodic index:

"The compatibility of two different metals may be predicted by consideration of their anodic index. This parameter is a measure of the electrochemical voltage that will be developed between the metal[s] and gold. To find the relative voltage of a pair of metals it is only required to subtract their anodic indices.

For normal environments, such as storage in warehouses or non-temperature and humidity controlled environments, there should not be more than 0.25 V difference in the anodic index. For controlled environments, in which temperature and humidity are controlled, 0.50 V can be tolerated. For harsh environments, such as outdoors, high humidity, and salt environments, there should not be more than 0.15 V difference in the anodic index.".

$\begin{array}{lc} \\ \text{Metal} & \text{Index (V)} \\ \hline \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \quad \text{Most Cathodic} & \\ \hline \text{18% chromium type corrosion-resistant steels} & −0.50 \\ \text{Chromium plated; tin plated; 12% chromium type corrosion-resistant steels} & −0.60 \\ \text{Tin-plate; tin-lead solder} & −0.65 \\ \text{Lead, solid or plated; high lead alloys} & −0.70 \\ \text{2000 series wrought aluminum} & −0.75 \\ \text{Iron, wrought, gray or malleable, plain carbon and low alloy steels} & −0.85 \\ \text{Aluminum, wrought other than 2000 series, or cast alloys (silicon type)} & -0.90 \\ \text{Aluminum, cast other than silicon type, cadmium, plated and chromate} & −0.95 \\ \hline \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \qquad \text{Most Anodic} & \\ \hline \end{array}$

Note: The difference between stainless and aluminum.