Steam pipe

JM_2

What are the types of pipe found on a steam system?
I hear the term "Iron Pipe" is this realy iron or did it used to be iron and now it is steel?
Is "Black Pipe steel or iron" and whatr is maleable pipe?

Thanks

Tony Conner

There Used To Be..

...wrought iron pipe, but they haven't made it for decades. Carbon steel pipe is what is available now, but there's no ASME designation for it as "black". That's a wholesaler's term to distinguish between carbon steel pipe and galvanized carbon steel pipe. The 3 main grades that are stocked are A53F which is furnace or continuous weld. It's made by taking a flat strip of steel, heating it up, then running it through rollers to make a tube, and the hot edges are pressed together. It's really a pretty crappy grade of pipe. A53B ERW is made pretty much the same way, except that the seam is electric resistance welded. It's a much better grade of pipe. Galvanized pipe will be one or the other, but it's just been dipped is all. It's exactly the same pipe. The best normally stocked grade is A106B. This is seamless pipe, and is made by drawing a solid round bar over a mandrel or billet. When you buy pipe nipples, they'll almost always be A53F, unless you specifically ask for A106B. The A106B jobbies will have that designation stamped right into them.

There is no malleable pipe. There are 150# and 300# malleable iron fittings though. They're a lot like cast iron fittings, only less brittle, so they have a higher pressure rating. Galvanized fittings are 150# malleable that have been dipped.

JM_2

thank you