While looking for corrosion resistance, you have probably heard of the phrase “stainless or galvanized steel”, as if these were interchangeable options. In fact, they are not at all.
Galvanization – Zinc Dip as Paint Job
Galvanized steel is corrosion-resistant because it has been hot-dipped, typically in zinc. In essence, this process jackets the steel in a relatively impervious layer. This gives it essentially the same mechanical properties as a paint job. And just like a paint job, if you scratch galvanized steel (or drill through it, or cut through it), you expose the inner layer which is very susceptible to corrosion.
Stainless – Self-healing and Permanent
The physical properties of stainless steel are quite different. It is corrosion-resistant because of a molecular effect called passivation, in which chromium oxide molecules immediately “heal over” any scratch or cut to the metal, no matter how deep. It is possible to break down stainless steel in, say, certain marine applications. Or otherwise in the presence of very strong acids. But archaeologists often consider it to be one of the few permanent materials that humans can create. If you leave a stainless beam or channel sitting in the woods, you can come back in a million years and it will still be just fine.
Working the Metals
Stainless steel is becoming more and more popular and most fabricators are comfortable working with stainless. Stainless Structurals makes the availability of stainless shapes a non-issue. It is relatively easy and safe to weld. By contrast, galvanized steel produces highly toxic fumes when a welder works on or even cuts it. However, it requires considerably more attention to ventilation and respiration safety.
Aesthetics and Maintenance
Stainless Structurals can provide steel members in a variety of formats. The intrinsic elegance of the metal allows you more flexibility in design, whereas galvanized steel (outside of highway infrastructure) is usually hidden. Moreover, there are several possible mill finishes for stainless steel, since there is no danger of injuring a corrosion-resistant coating. We can texture it with a wire brush or sander. In addition, we can polish it to a mirror finish, or leave it matte. Stainless does not corrode, ever, and it can be cleaned with alcohol or custom products.
Strength of Stainless and Galanized Steel
Ultimately, any metal construction has to consider the question of strength. The mechanical properties of stainless steel (specifically, its stress-strain curve) is considerably different from the usual steels that go into galvanized construction members. Compared to most carbon steels, stainless steel has a higher yield point. It resists deformation for longer than other steels. It also does not fail all at once, as most carbon steels do.
Conclusion
Imagine yourself choosing the materials for a project in the design phase of a job. One must consider the longevity and durability. Furthermore, one should think about future replacement costs. While galvanized may seem cheaper initially, in the end it can cost much more with replacement, re-finishing, and cleaning costs. Stainless steel is the best choice and eliminates these extra costs. Call Stainless Structurals today for help with material selection on your next project.
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