Metal to metal contact for stainless steel
Metal to metal contact for stainless steel
(OP)
Hi all, I just graduated and join a company on O&G industry. We deal with pipe for casing and tubing in a oil well.
Sometimes the pipes are made of stainless steel (13Cr, 22Cr, inconel etc). I was told that metal-to-metal contact for such material should be prevented as it will cause corrosion.
I don't understand how corrosion would start if stainless steels are in contact with or impact against each other. I'm also not sure whether this rule applies to all stainless steels or only certain grades.
Can somebody please help me clear the doubt, or recommend a reference book?
Thanks in advance.
Sometimes the pipes are made of stainless steel (13Cr, 22Cr, inconel etc). I was told that metal-to-metal contact for such material should be prevented as it will cause corrosion.
I don't understand how corrosion would start if stainless steels are in contact with or impact against each other. I'm also not sure whether this rule applies to all stainless steels or only certain grades.
Can somebody please help me clear the doubt, or recommend a reference book?
Thanks in advance.





RE: Metal to metal contact for stainless steel
Mike Halloran
Pembroke Pines, FL, USA
RE: Metal to metal contact for stainless steel
= = = = = = = = = = = = = = = = = = = =
Plymouth Tube
RE: Metal to metal contact for stainless steel
To make it clearer, I was talking about m-t-m contact during manufacturing and handling. Galvanic corrosion is not a concern as pipes for a particular job are usually of same material.
We use plastic rings (bumper rings) or pipe cradles or wooden blocks to separate stainless pipes/products.
Another benefit of doing so is prevent them hitting against each other and cause damage. But that is not what I'm interested in.
RE: Metal to metal contact for stainless steel
Chemical treatment exist to avoid any problem after fabrication, it is called passivation.
Look that up:
http://www.stainlessfoundry.com/FreeIron.asp
RE: Metal to metal contact for stainless steel
Very helpful article.
One question:
will free iron contamination, if left untreated, damage the passive chromium oxide film at the surface, and accelerate metal corrosion?
RE: Metal to metal contact for stainless steel
When the iron rusts it interferes with the formation of a coherent chrome oxide surface layer and it leaves a porous corrosion product. You now have the perfect site for initiation of crevice corrosion.
In many cases this happens in the field because of equipment and tools making contact. No advanced prep will offset this. All you can do is move to a more corrosion resistant alloy if it becomes a problem.
= = = = = = = = = = = = = = = = = = = =
Plymouth Tube
RE: Metal to metal contact for stainless steel
As Mike H says the potential problem with alloy casing and tubing is GALLING. I never saw a dissimilar metal problem in a well , not even with aluminum drill pipe ( which has steel connectors).
RE: Metal to metal contact for stainless steel
RE: Metal to metal contact for stainless steel
There might be some liturature but I suspect no absolute answer as to why Q & T steels in the lower strength ranges, like L-80, tend to gall.
RE: Metal to metal contact for stainless steel
RE: Metal to metal contact for stainless steel