Galvanic effect of brasses on various steels
Galvanic effect of brasses on various steels
(OP)
I am looking for information (websites or literature) on the cathodic effect that brass has on plain carbon steels as well as galvanized steels. I am aware that copper and copper based alloys are more noble than many of the cheaper steels which comprise black pipe and galvanized pipe. I am trying to determine the extent I have to worry about this form of corrosion on some of our products.





RE: Galvanic effect of brasses on various steels
If you have some sort of closed loop heating or cooling system, add corrosion inhibitors.
There is so much info: h
RE: Galvanic effect of brasses on various steels
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Rust never sleeps
Neither should your protection
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RE: Galvanic effect of brasses on various steels
Here are some decent tables:
http://www.assda.asn.au/asp/index.asp?pgid=18533
http:/
This one gives a good description of corrosion potential (volts) and material selection based on that potential:
htt
RE: Galvanic effect of brasses on various steels
(more info from previous site)
RE: Galvanic effect of brasses on various steels
Eventually I think some folks quite early on also discovered that at least in some applications they would not get near as drastic localized corrosion (and maybe even reasonable service life in many applications?) when the coupled galvanic areas/relationships were the other way around. I have noticed the fastener site at ht
I think some consensus standards, e.g. ANSI/AWWA C111/A21.11, I suspect based on a great deal of experience and testing over decades, also appear to sort of take many of these factors into account (as well as common bolting stress) when they require special alloy steel bolting e.g. to be used for buried mechanical joint fasteners with ductile iron piping systems. The alloy steel, while of course at least some dissimilar, metal is specially compounded with at least a small amount of nickel, copper, and chrome so as to service (remain pretty much at least slightly cathodic over time) pretty well in most normal soil environments, at least when bolted firmly to the ductile iron. I understand other compositions of bolted assemblies (I suspect with many piping materials)have not fared as well.
All that being said, I understand it is possible that even injudicious couples/area ratios might provide suitable service in even aggressive conditions when provided with coating applications and/or life-extending cathodic protection currents, with suitable potential designed and maintained to overrride deleterious galvanic effects.
While I am talking about electrical currents, I would make one other comment – another poster has referred to a plumbing code for “dielectric unions”. The Ductile Iron Pipe Research Association (DIPRA) website at http://www.dipra.org/ and in the document “DIRECT TAPPING OF DUCTILE IRON PIPE ENCASED IN POLYETHYLENE” provides special precautions/procedures most applicable in some aggressive soil environments for tapping ductile iron pipes and also suggests insulation of the (often copper) service line from the piping system in some circumstances, and particularly when stray DC currents might be imparted to the ductile iron piping by grounding of some electrical devices. This I suspect does not mean there would necessarily be any significant problem at least with a direct couple of the small surface area service etc. to iron pipes in other environments/conditions due to galvanic conditions, but that higher “stray” currents getting onto and then off of the pipes into the soil could exacerbate the conditions (by carrying much more pipe metal with them).