Rust-Back (Rerusting)

What Does Rust-Back (Rerusting) Mean?

Rust-back is a process of oxidation that occurs on bare carbon steel. When a steel is cleaned through mechanical or chemical means, then it can be completely exposed to the atmosphere. Rust-back will occur if it is exposed long enough and rust will form on the surface.

Rust-back is a major concern when it comes to ensuring the integrity of carbon steel. If carbon steel is cleaned and rust-back is allowed to occur, then the entire cleaning process was performed for no gain. Furthermore, if the rust-back occurred before a coating is applied, then the coating, once applied, could be subject to failure. If the coating fails then the oxidation of the steel could increase at an even greater rate.

Rust-back is also known as rerusting.

Corrosionpedia Explains Rust-Back (Rerusting)

Carbon steels are commonly cleaned either mechanically or chemically to eliminate any surface rust that is present on its surface. When the rust is removed the underlying unoxidized steel is exposed to the atmosphere. This atmospheric exposure can cause the unoxidized steel to oxidize, which results in a new rust layer forming on the cleaned steel. This cycle of rusting, cleaning and rusting again is why rust-back is also commonly referred to as rerust.