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Pipeline corrosion by salt or seawater

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mjdy615

Mechanical
Joined
Jul 12, 2007
Messages
1
Location
KR
Hi,
I am working to transport refined oil through pipeline and searching the corrosion caused by the salt or seawater.
Can anyone give me the data for below?
- Mechanism of corrosion by salt or seawater(Feature, Shapes, etc.)
- Case of pipeline corrosion(External, Internal) caused by salt or seawater
Thanks.
 
Look at API RP 571, which addresses mechanisms in detail.
 
salts are ionic solids : they have various properties depending on composition

chloride ions may be involved in the salt formula, but I believe chloride ions has little influence on the corrosion of carbon steel, in oposition with austenitic stainless steels that are sensitive to chlorides.

the risk on carbon steel material is most probably due to corrosion by dissolved oxygen
 
sea water is "normal corrosion" - there is oxygen in the water. The ions in the water helps. You protect the pipeline with anodes
 
1% Ni weld fillers are often used, which make the WM cathodic relative to the BM. In salt water (i.e. conductive electrolyte), this tends to protect the WM from preferential weld corrosion. Care must be taken if the water is diluted with fresh water and becomes less conductive, as Ni also increases the metal's intrinsic corrosion rate.
 
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