While stainless steel is a corrosion resistant material compared to mild or tool steel, it is truly stain-“less” steel rather than stainproof steel. Unfortunately in many situations even stainless steel can develop corrosion which can range from mild tea staining discoloration to thick, flaky rust. This can cause some understandable panic for owners of stainless steel equipment, tanks, railings, appliances, sinks, grills, boat hardware, sculptures, and other objects which go from beautiful to ugly due to the appearance of rust. The good news is that rust on stainless steel can be removed and prevented from rapid recurrence if the right steps are taken.
One of the most frequent causes for rusting on stainless steel are surface iron contamination that was deposited during or after manufacturing, and the alloy structure change along the heat affected zone of welds. These are corrosion situations that should be prevented with proper passivation, but are sometimes overlooked. Additionally, even stainless steel that has been passivated well can rust due to chloride attack from harsh chemicals such as muriatic acid, as well as long term exposure in highly corrosive environments such as swimming pools, marine areas, winter ice-melting salts, or frequent cleaning with bleach-based cleaners. In these circumstances, regular rinsing with clean water is helpful to remove the chlorides from the surface, but periodic repassivation is also recommended in order to keep the stainless looking nice.
If corrosion does appear, be it minor “tea staining” discoloration or full blown rust, it is important to deal with it as soon as possible. The longer the corrosion is allowed to persist, the worse it will become, and may even progress to very severe pit corrosion.
Removing rust from stainless steel is easy and can be achieved through the use of any number of different chemicals, abrasives, grinding, blasting, etc. However, using these methods does not address the vital issue of passivation to help protect the stainless steel from future corrosion. This is the most important part of remedying the rust issue because removal efforts seem wasted if the rust comes back again too quickly.
We offer several environmentally friendly, citric acid based CitriSurf® products that simplify the process by performing both tasks in one treatment so that the stainless surface stays clean and beautiful for as long as possible. Removing rust from and passivating stainless steel with CitriSurf products is quick, easy, safe and inexpensive.
CitriSurf 77 Plus and CitriSurf 2310 are the main rust removal and passivation products for on-site and large item jobs. The CitriSurf 77 Plus is a liquid for easy spray application, and the CitriSurf 2310 is a thicker gel version for brush or spray application that clings well to vertical surfaces and pipe/tubing exteriors, and is also great for weld joints.
We also offer CitriSurf 2325 for removal of rust from bulk quantities of parts in a bath or the inside of large tanks and piping systems using CIP operations.
The Rust Rescue™ products are not a surface sealant or coating, but a material that flows into any pits, pores, crevices, and other deep surface features to help protect them from corrosion-inducing air and moisture. This is especially helpful in highly corrosive environments and where pit corrosion has occurred, to keep new rust from bleeding out of the pits onto the surface.
The stainless should be cleaned and passivated with CitriSurf first, and after the surface is completely dry, Rust Rescue can be applied. Rust Rescue 200 is for general use, and Rust Rescue 100 is a food-surface safe version for FDA-regulated stainless surfaces.
Your stainless steel sink, fridge, oven, dishwasher, or railing is an investment that is well worth protecting. Proper maintenance of your stainless steel with CitriSurf and Rust Rescue is a great way to ensure that this investment stays in great condition for years to come.