SS316L Grade Welded Stainless Steel Square Pipe Railing BS 1000MM

Does Stainless Steel Rust?

Best practices in rust prevention from design to maintenance

Will stainless steel rust?

Stainless steel is armed with built-in corrosion resistance but it can and will rust in certain conditions—although not as quickly or severely as conventional steels. Stainless steels corrode when exposed to damaging chemicals, saline, grease, moisture, or heat for prolonged periods of time.

Stainless steel’s protection against corrosion is largely dependent on the amount of chromium present. If there is not enough chromium content near the surface of the stainless steel, a new chromium oxide layer cannot be formed when the top layer is scratched off. This leaves the material very vulnerable to several types of corrosion.

Stainless steel basics

To understand why stainless steel is rust-resistant, and how this resistance breaks down, it is helpful to understand how these alloys are different than other steels.

Stainless contains a minimum of 10.5% chromium. This chromium reacts quickly with surrounding oxygen to form a thin oxide layer on the steel’s surface. Unlike iron oxide, which often is in the form of flaky and corrosive rust, the chromium oxide clings to the steel. It therefore acts as a protective barrier. The chromium oxide is known as a passive film which seals the iron in the alloy away from the air and water in the environment. This film gives stainless its rust-resistance.

Stainless Steel Square Pipe Specification