Hi,
The company Force technology have developed a resistor controlled cathodic protection system (RCP) for handling such problems www.forcetechnology.com
Regards,
Mekanikeren
http://www.forecetechnology.com
The trend here in Norway is that most companies that earlier were using mineral wool is now using cellular glass in areas where the piping may be subject to humidity either from deluge testing or from marine atmisphere. I feel that the temperature in question 85C together with the exposure is so...
For crevice corrosion in seawater, the use of AISI 316 in the gasket may act as a "kickstarter for starting crevice corrosion even at the higher alloyed flange (since the environment inside the crevice keep souring from the creation of HCL from corrosion of AISI 316). AISI 316 is thus not...
Hi 180,
Previos safe limits for SCC on 22Cr duplex has been 90 deg.C. This is now raised to 100 deg.C in the NORSOK specifications. This imply that you can leave SAF 2205 bare.
If you want even more resistance to SCC you should evaluate to use 6MO as (254SMO or AL6XN or 1925HMo).
Nevertheless...
DouglasD,
YES 0,25 to 0,4 mm/year means 0.25 to 0.4 mm/year (These are ball park fiures)
Note that I agree with lauri to keep an eye on the development as corrosion rates may be much higher, all dependent on temperature and the amount of seawater changeout.
Also note at some point of coating...
DouglasD,
It sounds like you have a condition equal to a "splash zone" for an offshore structure where the surface is constantly wetted without the anodes working. In such cases the corrosion rate may increase to typical 0,25 to 0,4 mm/year /Ref. Fontana and N.D.Greene: Corrosion...
Hi,
I have been inspecting corrosion under insulation for a number of years and found a lot of corrosion on non cellglass systems.
DO NOT USE ROCKWOOL OR ANY FIBER AS IT KEEPS MOISTURE AND WATER.
It is Cellular glass (Foamglas) you need ref. MGP's reference!
Foamglas with it's open cell...
Hi,
Rust surface attacks often occur on AISI 316 in marine athmosphere in heat affected zones at field welds or at areas where the surface have been in contact with carbon steeel as e.g. wire rope slings.
From a number of companies as e.g. Avesta-polarit you may purchase a jar of...
Hi DouglasD,
Corrosion in seawater is at approx 0,1 to 0,2 mm/year with a good access to oxygen as if the ballast water is changed out frequently. (This is also dependent on temperature).
If there is a lot of dirt at the bottom and no working cathodic protection system (sacrificial anodes), it...
If the problem is on the brine side, cathodic protection may be an answer. Check out the January number of NACE Materials Performance on Cathodic Protection.
