Why Do Stainless Steel Kitchen Equipment Pieces Rust?

After buying stainless steel kitchen equipment, some users see rust after a period of service. Why? CHINENG explains the common causes.

Why stainless steel kitchen equipment rusts

1. Construction residues: alkaline water, lime water, and oil left on the surface during fit-out will cause local corrosion if not cleaned promptly.

2. Iron contact: long use of nails, wire, or other iron tools on a stainless sink can leave rust spots.

3. Process and material issues

1) Cutting/heating: flame-affected zones change composition and microstructure, form galvanic cells with corrosive media, and corrode electrochemically.

2) Welding: physical defects (undercut, porosity, cracks, incomplete fusion/penetration) and chemical issues (coarse grain, chromium depletion at grain boundaries, segregation) also form galvanic cells.

3) Passivation: poor acid pickling and passivation leaves an uneven or thin film that corrodes easily.

4) Material: chemical nonuniformity (S, P impurities) and surface defects (porosity, sand holes, cracks) favor galvanic attack.

5) Cleaning: residual pickling solution reacts with stainless steel and can start electrochemical corrosion.

4. Metal dust: mineral, acid, or alkali metal dust from decoration, plus humidity and condensate, can create electrochemical spotting and rust.

5. Pipe debris: iron filings and rusty water in new buildings leave rust marks if left on stainless surfaces without rinsing.

6. Fit-out materials: stainless steel is corrosion-resistant but not immune. Residue water, cement, lime oil, paint, and metal dust can all attack sink and equipment surfaces.

In summary: those are the main reasons stainless steel kitchen equipment rusts. For CHINENG commercial kitchen equipment, contact our online technical team. We will keep publishing related guidance.