Stainless steel corrosion or rust formation

Stainless Steel Corrosion or Rust Formation

Although stainless steel is chosen for its corrosion-resistant properties, it is not completely rust-free. Alinco has years of experience in stainless steel processing, and we rarely encounter corrosion problems. However, having sufficient knowledge and being aware of potential issues can help prevent corrosion as much as possible from the design stage.

Important: Rust Formation on Stainless Steel is Not Always a Problem Rust formation on stainless steel is not always a problem; sometimes it is, of course.

A Few Important Guidelines:

  • Chlorine is the Enemy of Stainless Steel. Stainless steel and chlorine do not mix. Chlorine and chlorine products are one of the biggest enemies of stainless steel, especially the most used grade AISI 304.
  • Using chlorine causes rust formation.

External Contaminations

Despite the correct material choice, external contaminations can cause the piece to 'rust.' Classic examples are iron particles in the air that settle on the stainless steel. For example, in stainless steel facade cladding next to a railway line or if someone has been grinding iron near a stainless steel piece.

Choose the Right Stainless Steel Grade

  • Aggressive products pose a risk of corrosion. The customer generally determines the material grade, and incorrect material grade selection sometimes occurs. Therefore, it is crucial for non-experts to mention the potential application (indoor, outdoor, aggressive environment, or swimming pool) when requesting a quote to ensure the correct material grade is offered. You do not simply order a 'ground or brushed stainless steel pipe,' but rather a 'ground stainless steel pipe for outdoor use.'
  • Ensure the Right Material Grade Using Corrosion Tables. The most commonly used grades are AISI 304 and AISI 316; here is some extra info on the choice between AISI 304/316.

What to Do If Stainless Steel Starts to Rust?

Correct material grade choice means rusting stainless steel is not a disaster. Often this has explainable causes (usually external contaminants); remove these, and the corrosion problem is solved.

Some logical steps:

  • Maintenance: Clean the stainless steel thoroughly with chlorine-free products. Often thorough cleaning or re-pickling can solve the problem.
  • Pickling: This removes iron-like contaminants and helps the material form a self-healing layer.
  • Electropolishing: Can provide a solution but can change the aesthetic appearance.
  • Special Cleaners: Use specialized rust removers if necessary.