Chloride Concentration on Pitting Resistance
2

Question

Chloride Concentration on Pitting Resistance

knowkeys (Marine/Ocean)

(OP)

16 Sep 03 08:45

I was wondering if anyone has had any experience or can provide guidelines on an acceptable level of chloride.

I have an application where a "super duplex" pipe (25Cr) with a pitting resistance number > 40 is exposed to seawater (not flowing) . The concentration of NaCl can be reduced, however, I need guidance on the minimum acceptable level to prevent pitting.

Thanks

mcguire (Materials) · Answer 1 · 2003-09-16 10:29:31

This has been well researched. One needs to know the temperature, however. Also, what is the surface condition? And has it been welded?

knowkeys (Marine/Ocean) · Answer 2 · 2003-09-16 10:59:40

Thanks for the prompt response

The temperature will be between 5 and 15 deg C.
The pipe is welded but has been coated. The surface should be in good condition. This will be the worst case.

Can you provide a link or reference to the research.

mcguire (Materials) · Answer 3 · 2003-09-17 16:10:59

There is a great collection of papers on this topic in "Applications of Stainless Steels '92". I would also recommend the the AvestaPolarit website. You can enquire there dirctly. They pioneered these grades and are the most expert company in their use. (The best advice is right here)

knowkeys (Marine/Ocean) · Answer 4 · 2003-09-18 07:03:11

That is an excellent website and I was able to make use of the information provided. Thanks very much.

Metalguy (Materials) · Answer 5 · 2003-09-18 14:21:51

Knowkeys,

So give him a red star if he helped you!

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Chloride Concentration on Pitting Resistance
2