Can Stainless Steel Rust?

Monday, October 22, 2018

Tags: stainless steelcan stainless steel rustcorrosion

Stainless Steel is the most popular choice for sinks worldwide, one of the reasons being its ressitance to corrosion.

Yet the Warranty Centre at Franke South Africa does receive the occasional call that starts with “My sink is rusting!” So how is this possible?


How do Stainless Steel sinks corrode?

Stainless steels, because of their resistance to corrosion, are often used in highly aggressive conditions, which will cause most alternative materials to fail rapidly. However if given the opportunity Stainless Steel can corrode or 'rust'.  Stainless steel is being protected from a corrosive environment by a very thin, but tenacious surface layer which is formed when the chrome in the material reacts to the oxygen in the surrounding air. The layer does get damaged by handling and work being done on it. But should the material be cleaned and again exposed to oxygen, it will naturally reform itself. When the layer is damaged and exposed to corrosive chemicals or conditions, discolouration can appear and if not treated it can lead to “rusting”.

Franke’s premium chrome-nickel stainless steel sinks will not stain under normal conditions, but may corrode if exposed to harsh chemicals. The most common culprit of chemical pitting corrosion in kitchen sinks is chloride containing  solutions such as salt and certain bleaches.

Another substance that can cause rust-like eruptions if left in contact for an extended period of time is Triclosan, an organic chemical found in many anti-bacterial soaps and popular toothpastes. This chemical has come under scrutiny in recent years on whether it is safe for use and one should consider avoiding products with this ingredient until the research is clearer.

Even leaving something as seemingly harmless as salt, vinegar, citric fruit juices, mustard, mayonnaise or pickles on the surface of your sink for a lengthy time can cause pitting and corrosion. Franke therefor recommends simple daily cleaning routine of your sink to remove contaminants and keep your sink looking like new.


How to remove rust?

Any rust that appears on stainless steel is the result of mechanical or chemical damage to the protective layer as caused by metallic scouring pads and harmful chemicals. The good news is you can remove it easily if it starts to appear!

We recommend using a use mild dishwashing soap with clean warm water. Apply it with a soft cloth to the sink and clean it in a circular motion. Thoroughly rinse away any cleaning product once finished and dry the sink thoroughly after cleaning. And lastly when cleaning your stainless steel, NEVER USE STEEL WOOL PADS. We, and our stainless steel sinks, thank you in advance!


Cleaning products to avoid using on your sink:

  • Abrasive cleaners like bleaches containing hypochlorite
  • Silver dip cleaners
  • Strong acids like photo developing liquids or denture cleanser. If they come in contact with your sink, they should be washed away immediately with clean water
  • Using steel wool pads


Storage of cleaning products:

The space under your kitchen sink is often the most common choice for storing cleaning products. This area is not only dangerously accessible for children and pets but storing these harsh chemicals can cause even the highest grade of stainless steel sink to corrode!

Consider storing your cleaning products on the top shelf of a laundry room, in your garage or in a locked closet. If storing your cleaning products under the kitchen sink is your only option – ensure all bottles are tightly sealed closed and add a shelf below your sink to separate and protect the underneath of your sink from prolonged exposure to these chemicals.

What not to store under your sink:

Harsh Chemicals like…

  • Toilet cleaner
  • Caustic Soda e.g. Drain Cleaner
  • Pool Acids
  • HTH and Products containing Chlorine


Stainless Steel is a truly remarkable metal that that will not rust under normal atmospheric conditions or in water based environments. Simply being aware of and avoiding those specific aggressive conditions which are conducive for corrosion in stainless steel will help keep your Franke sink corrosion free for many years and often for generations of use!


More technical information can be found on the Franke website as well as through the Southern African Stainless Steel Development Association or SASSDA (+27(0)11 883 0119) who offer assistance and education on Stainless Steel.



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