Polishing Technologies and Quality Requirements for Stainless Steel Reactors

The Role of Polishing in Reactors

• Enhanced Corrosion Resistance: A polished surface promotes the formation of a robust passivation layer made of chromium oxide, shielding the metal from chemical attacks.
• Improved Hygiene: Smooth surfaces reduce media adhesion, making reactors easier to clean and sanitize, which is vital in pharmaceutical and food sectors.
• Efficient Fluid Flow: High - 光洁度内表面 minimizes liquid resistance and stagnant areas, ensuring consistent reactions.

Main Polishing Techniques

1. Mechanical Polishing

• Rotational Polishing:
  Equipment includes a power - driven disc, abrasive belts, and polishing compounds. The disc rotates against the surface, refining it with different grits. It's cost - effective for small - to - medium production but can leave scratches if not done carefully.
• Linear Polishing:
  Ideal for long, cylindrical tubes, it uses abrasive pads or brushes moving along the inner surface to remove irregularities.

2. Electrolytic Polishing (Electrochemical Polishing)

• The reactor (anode) is placed in an electrolytic solution (e.g., phosphoric and sulfuric acid mixture).
• With a low - voltage, high - current supply, two reactions occur: passivation (oxide layer formation) and dissolution (metal ion removal).
• Micro - level differences in the surface cause the 凸起部分 to dissolve faster, resulting in a high gloss finish with a surface roughness of Ra 0.2–0.4μm. This method boosts corrosion resistance and works well on complex shapes, though it requires precise control of process parameters.

Quality Requirements

1. Surface Roughness

• Pharmaceutical Industry: Demands Ra ≤ 0.4μm for internal surfaces to comply with GMP, reducing microbial adhesion.
• Food and Beverage Industry: Typically requires Ra ≤ 0.8μm, balancing hygiene and cost.

2. Passivation Layer

3. Visual and Hygiene Checks

Conclusion