Metallurgy in Oil & Gas Service - Brass and Ductile Iron

[ChEMatt]

Forgive my ignorance here. I got asked a question that I had not considered before so I don't have a good answer at the moment. Hope y'all can help.

Why is it we generally don't see brass or ductile iron in oil and gas (upstream or midstream) service? My first answer was that ductile iron probably has a tendency to rust and corrode a lot easier than carbon steel, but I am admittedly talking out of my behind, so to speak.

For sour, and non-sour services, why don't we see more of this metal in oil, water, and gas gathering, wellhead, well pad facility, separators, treaters, tankage, and midstream processing? Or do we and I never noticed?

Thanks folks,

-Matt

 

[chicopee]

For what is it worth, brass fittings on ammonia storage tanks is inadvisable so I suspect that brass fittings may be incompatible with whatever ever contaminants in oil and gas service.