Standard for peening to prevent stress corrosion cracking
Standard for peening to prevent stress corrosion cracking
(OP)
Is there an industry standard that I can quote for peening of stainless steel to minimize/prevent stress corrosion cracking.
I would like to use this for mitigating Cl SCC on a solid stainless steel lube oil cooler that occassionally has to be sprayed with water to help with additional cooling.
(lube oil must be in contact with stainless for product cleanliness) I can paint, but it is likely to deteriorate. Duplex is cost prohibitive.
Any help would be appreciated.
I would like to use this for mitigating Cl SCC on a solid stainless steel lube oil cooler that occassionally has to be sprayed with water to help with additional cooling.
(lube oil must be in contact with stainless for product cleanliness) I can paint, but it is likely to deteriorate. Duplex is cost prohibitive.
Any help would be appreciated.





RE: Standard for peening to prevent stress corrosion cracking
Peening is indeed allowed under UW-39 and AF-234. However, it is common practice to ban the peening on the Stainless Steel pressure equipment and particularly on welds (including the Austenitic Stainless Steel pressure parts), as the peening could be an initiator for SCC. In fact, most of the O&G major specifications (Shell, BHP, etc) are simply banning the peening altogether, to avoid the risk of misinterpretation and potential damage to the pressure equipment.
As the standard for the peening process, I could help only with an Australian reference, if it is of any use to you.
Also, I would think that you should have many more replies, perhaps better ones (hey, boys!!)
Cheers,
gr2vessels
RE: Standard for peening to prevent stress corrosion cracking
The problem is that the entire surface needs to be shot peened to be effective, not just the weld or base metal HAZ. This can be very costly, and is not really practical for vessels.
RE: Standard for peening to prevent stress corrosion cracking
Mike Halloran
Pembroke Pines, FL, USA
RE: Standard for peening to prevent stress corrosion cracking
Is a lean duplex really more expensive than unit fialures? Don't only look at 2205, LDX2101 might be a good alternative. Ifyou look at duplex make sure that you also look at making the walls thinner, since the alloy is so much stronger.
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RE: Standard for peening to prevent stress corrosion cracking
My results in migrating Cl/SCC were quite varied. Laboratory work went very well while the field test left a lot to be desired except in a few cases. Tests in salt water were inconclusive.
h
Go to this page and type in SCC.
http://www.shotpeener.com/library/index.html
Laser Peening:
Just before I left I had procured some Laser Peened samples of 304L that were showing excellent results in mitigating Cl/SCC in the lab. I had a few centrifuge parts Laser peened but have since learned that they were never installed.