Типы коррозии труб и как их предотвратить

Коррозия трубопровода очень распространена в реальном рабочем процессе. Тогда сколько вы знаете об этом? Что вы должны сделать, чтобы предотвратить это? В этой статье рассказывается о 10 типах коррозии труб и рассказывает о способе профилактики для каждого из них.

1. Electrochemical corrosion
   Reason: metal and electrolyte contact REDOX reaction.
   
   Prevention methods:
   Cathodic protection (sacrificial anode or impressed current).
   Use anti-corrosion coatings (e.g., epoxy resin, polyethylene coating).

2. Chemical corrosion
   Reason: Metals react directly with chemicals such as strong acids and bases.
   
   Prevention method:
   Choose corrosion resistant materials (such as titanium alloy, Hastelloy).
   Control the composition of the medium (e.g., adjust pH to reduce corrosive substances).

3. Pitting (pitting)
   Cause: Local chloride ions or sulfides cause small holes to form on the metal surface.
   
   Prevention methods:
   Use pitting resistant materials (such as 316L stainless steel, duplex steel).
   Add corrosion inhibitors (such as molybdate, nitrate).

4. Microbial Corrosion (MIC)
   Reason: sulfate-reducing bacteria and other microorganisms metabolize acid or sulfide.
   
   Prevention methods:
   Clean pipes regularly and use fungicides or bioinhibitors.
   Keep the pipe dry or control the temperature to inhibit microbial growth.

5. Stress Corrosion Cracking (SCC)
   Cause: Tensile stress and corrosive environment (such as chloride ions, high temperature).
   
   Prevention methods:
   Remove residual stress (annealing treatment).
   Avoid using sensitive materials (such as austenitic stainless steel in chlorine environments).

6. Uniform corrosion
   Reason: The surface of the metal is uniformly eroded by the corrosive medium.
   
   Prevention methods:
   Increase wall thickness to reserve corrosion margin.
   Use a coating or lining (such as a rubber lining).

7. Crack corrosion
   Reason: The concentration battery is formed by the retained corrosion medium in the gap of the pipeline.
   
   Prevention methods:
   Optimized design to avoid gaps (e.g. welded instead of bolted).
   Fill gaps with sealant.

8. Hydrogen brittle
   Cause: Hydrogen atoms penetrate into the metal causing brittle fracture.
   
   Prevention methods:
   Control the hydrogen sulfide content in the medium.
   Low strength steel or hydrogen trap alloy.

9. Erosion corrosion
   Cause: high-speed fluid impact damage the surface protective film.
   
   Prevention methods:
   Reduce flow rate or change direction design.
   Use wear-resistant materials (such as silicon carbide coatings).

10. Stray current corrosion
    Cause: An external current (such as a tram track) triggers an electrolytic reaction.
    
    Prevention methods:
    Install drain device or insulation flange.
    Strengthen insulation protection between pipeline and soil.