Stainless steel is often chosen for its corrosion resistance and ease of cleaning, making it widely used in medical, home, and industrial applications. However, improper cleaning methods can lead to scratches or corrosion on the surface, affecting both aesthetics and longevity. Therefore, it is essential to maintain the surface's smoothness.

Does Stainless Steel Tarnish?

Stainless steel does not tarnish in the traditional sense, but in certain circumstances, it can lose its shine or change color:

• Exposure to Harsh Chemicals
  Prolonged contact with strong acids, bleach, or saltwater environments can damage the protective chromium oxide layer, leading to rust or discoloration.
• Improper Maintenance
  If stainless steel is not cleaned regularly, dirt, oil, and other residues can accumulate, causing the surface to appear dull.
• High Humidity or Chlorine Exposure
  In high humidity or chlorine-rich environments (such as swimming pools), stainless steel may show signs of pitting or staining over time.

Cleaning Stainless Steel Surfaces

• Electrolytic Polishing
  Also known as electrochemical polishing, this process uses the metal as an anode in an electrolyte solution. Under the influence of applied direct current, it selectively dissolves the raised microscopic parts of the surface, resulting in a smooth, shiny, clean, and corrosion-resistant finish. Electrolytic polishing is an efficient and environmentally friendly surface treatment technique that not only enhances the appearance of the metal but also significantly improves its performance, making it widely applicable in scenarios requiring high gloss and corrosion resistance.
• Passivation (Chemical Cleaning)
  Typically, stainless steel is immersed in a nitric or citric acid solution and then rinsed with clear deionized water and dried. If immersion is not feasible due to the size of the stainless steel part, a suitable cotton swab can be used to apply the acid solution, followed by rinsing with water. Nitric acid is recommended as it can dissolve all iron particles without affecting the stainless steel itself. For chemical cleaning to be effective, the stainless steel surface must be free of scale, heavy grease, and oil.

Cleaning Recommendations for Special Scenarios

• Medical and Food-Grade Stainless Steel
  316L stainless steel can withstand high-pressure steam sterilization (121°C) and gamma radiation disinfection, making it suitable for reusable instruments. However, remember to rinse with pure water after cleaning to avoid chemical residues that could affect safety.
• Industrial Processing Stains
  For industrial degreasing of stainless steel, ultrasonic cleaners with alkaline degreasers should be used, heated to 50-60°C to enhance cleaning efficiency. Acidic cleaners (such as mixtures of nitric acid or hydrofluoric acid) can quickly dissolve oxides, but strict protective gear must be worn.

Maintenance and Protection Tips

• Regular Care
  Every month, apply a thin layer of olive oil or a specialized stainless steel maintenance product to the surface to form a protective film, reducing the adherence of fingerprints and stains.
• Dry Environment Maintenance
  After cleaning, promptly dry the surface, as it is prone to pitting in humid environments (especially with 304 stainless steel).
• Avoid Contact with Corrosive Substances
  When the surface of stainless steel is exposed to salt, bleach, or chloride ions (such as pool water), it should be cleaned immediately to prevent localized corrosion.

Sunning Steel Limited possesses professional knowledge and services to provide you with stainless steel products suitable for various applications. Consult us to achieve your desired appearance for finished components.