Geoff,
I think you missed the intent of the question from Thomas. He is asking about
Galvanic corrosion. I'll put my 2 cents in.
Galvanic corrosion - between two dissimilar metals will result in accelerated
corrosion of the more reactive metal and less corrosion of the more stable
metal. This situation is most severe in the more opposite type metals or those
farther apart in galvanic series. Copper and steel would be an example of two
metals that would have a problem. An insulated joint or galvanic coupling would
be neccesary. This joint would electrically insulate the two different metals.
In my limited experience I would guess that steel and stainless steel would not
be a problem but thats where my knowledge drops off. Also undergound systems
would add a level of concern too.
Pete
Thomas,
In a dry environment there will not be corrosion. In a wet or moist environment
there will be. Generally where it rains and then dries out the corrosion will be minimal. In a salt water environment the corrosion would be severe.
Sydney Water go to the extreme of requiring insulating gaskets and washers under bolt heads in such environments where dissimilar metals occcur.
I do not know of any code requirement covering this matter. Generally the requirement is set out in company standards.
I would have thought someone employed by Nalco would know these facts! The discussion appears in the books published on corrosion by Nalco. So the question sounds a bit of a "Dorothy Dixer" to me. (for those not familiar with the colloquial expressions of the English and Australian parliaments the latter
term covers the questions put by one's own side. The intent being to allow a colleague to spruke on about a matter that would in the normal course of events
never have been raised.)
Geoff Stone
Gentlemen:
involved with installation of carbon steel and stainless steel piping. piping is 150# class, and line sizes are 4 thru 10 inches. is there a need for galvanic isolation between dissimilar spools?
thank you for your help.
Thomas G Laupa PE
Senior Engineer - Ondeo Nalco Applied Services
Office Address: One Ondeo Nalco Center, Naperville, IL, 60563
Courier Address: 1003 Remington, Fort Collins, CO, 80524
970-227-5127
800-493-5009 fax
Yahoo! Groups Sponsor ADVERTISEMENT
Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
Overseas tel 61 2 402 35 2313 fax 61 2 8850 2313 mobile 0402 35 2313 Mail Address PO Box 1351 Castle Hill NSW 1765 Australia
Yahoo! Groups Sponsor
Research, and Software, Ltd.
Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
[Non-text portions of this message have been removed] Received on Sun Jun 01 22:53:00 2003
This archive was generated by hypermail 2.1.8 : Tue Mar 09 2010 - 00:20:44 EST