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Have you ever wondered if stainless steel and aluminum can be used together in your projects? If you’re in the fastener industry, this question might have crossed your mind more than once.
Yes, you can use aluminum and stainless together, but the combination of aluminum and stainless steel can cause galvanic corrosion, so you need to take corrosion prevention measures. such as, you can place a rubber gasket or washer between the two metals or use insulation, coating and other barrier measures to prevent galvanic corrosion.
It’s not that simple to combine those two metals, but it definitely can be done with a little more care. So let’s get into the details of using stainless steel and aluminum together.
What is Galvanic Corrosion?
Galvanic corrosion happens when two different metals are in contact with one another in an electrolyte, such as water, seawater, etc. In the case of stainless steel and aluminum, the aluminum will be the anode (active) and the stainless the cathode (inert). Electrons will flow from the aluminum to the stainless steel, accelerating the corrosion of the aluminum.
Think about how this works in the real world. In maritime environments, aluminum hulls in contact with stainless steel props are prone to galvanic corrosion problems. Aluminum window frames with stainless steel screws also corrode at the points of contact. In air and space applications, aluminum aircraft bodies with stainless steel fasteners are also susceptible.
A few things you can do to prevent it: insulate materials to keep the different metals separate, use metals with similar potential, and use sacrificial anodes. All of these different ways are essential when you design structures and utilize both metals.
Steel and aluminum reaction: Examples of Safe Usage
We often get asked if it’s safe to use stainless steel fasteners with aluminum. The short answer is yes, it’s possible, but nevertheless, it’s not always the best idea. You’ll need to take some precautions if you want your project to be successful. Let’s look at some situations.
- Road or Bridge Railings: Stainless steel fasteners are used to secure aluminum railings on roads or bridges. This combination leverages the lightweight, corrosion-resistant properties of aluminum and the strength of stainless steel. Insulating spacers and anodized coatings on aluminum can further enhance corrosion resistance. This setup is durable and visually appealing, suitable for outdoor environments. Regular inspections ensure there are no signs of corrosion, making it a reliable choice for infrastructure projects.
- Marine Environments: Stainless steel bolts and aluminum components can coexist safely in marine environments. For instance, stainless steel bolts are used to secure aluminum structures on boats. Marine-grade stainless steel (like 316) and anodized aluminum alloys (like 5052 or 6061-T6) are selected for their superior corrosion resistance. Insulating gaskets or coatings are applied to prevent direct metal contact, and maintenance routines include regular inspections and cleaning to prolong their lifespan. This combination is effective even in harsh saltwater conditions.
How to prevent galvanic corrosion between aluminum and stainless steel?
To prevent galvanic corrosion between stainless steel and aluminum, you can:
- Add insulation: Place plastic or rubber washers, or use well nuts between the two metals.
- Use materials with similar potential: Use metals with the same corrosion resistance as much as possible.
- Prevent electrolyte contact: Keep materials dry or use corrosion-resistant coatings.
- Coat to protect: Coat or paint components completely to prevent electrolyte contact.
- Choose the right materials for the environment: Select materials based on their use in certain environments.
- Use corrosion-resistant materials: Use anti-seize compounds or washer under nuts and bolts.
It’s relatively safe to use stainless steel fastener on big aluminum surfaces, but I wouldn’t recommend doing it the other way around. If you’re attaching steel to aluminum, go for carbon steel fasteners and use non-absorbent insulation like rubber or plastic where they make contact.
Conclusion
Yes, as stated in the beginning of this post, you can use them together, just take the right precautions to prevent galvanic corrosion. By understanding what causes galvanic corrosion and taking precocious measures to prevent it, the two can be happily married together in a variety of applications. Whether it’s at a home, at sea, or in the air, taking care in the design phase and then maintaining that structure, will help you perform to ensure long life and great performance.
Following these practices will help you get the advantages of both metals without falling into the corrosion trap. As the leading industrial fastener supplier, our team at Hengrui is here to provide quality solutions and expert advice to help you achieve your goals.
For further information on our products and services, please visit our website or contact us at info@hrfastener.com.
