A corrosão do pipeline é muito comum no processo de trabalho real. Então, quanto você sabe sobre isso? O que você deve fazer para evitá -lo? Este artigo fala sobre 10 tipos de corrosão de tubos e conta o caminho de prevenção para cada um deles.
- 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).
- 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).
- 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).
- 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.
- 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).
- 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).
- 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.
- 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.
- 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).
- 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.