any pipe fitter/welders

[chuck172]

40+years as a union pipefitter/certified nuclear welder.I would Tig the first pass and hot pass with Tig and 7018 out.You could Tig all the way if you chose.Maybe four or five passes.No need to purge on carbon steel.

Same background and experience as you. Your procedure is for a powerhouse, not someones basement boiler.

 

[Jorville]

I realize this is for your own system but I see a potential problem. You're asking questions about purging mild steel and thinking the caps are cast steel. Are you using seamless pipe suitable for welding a pressure sytem? This is a pressurized boiler system so I have to ask, are you a certified pressure welder? I believe anything over 7 psi requires a pressure ticket(s). 12 psi cold is certainly going to be higher when heated. If something went wrong you could be in a lot of trouble. Not trying to discourage you, just asking. If you roll the welds, get some wheels to roll the pipe. Trying to roll it on a piece of angle iron isn't going to roll smooth enough.

Arc Weld, I am not sure if the pipe is seamless, it is domestic, U.S. made. The pipe has beveled ends for welding. I had to buy 21 feet to get the piece I needed. The couplings and caps are domestic, U.S. made. The threaded pipe fittings that I will be using I hope will be U.S. made. Any pipe that I need that has to be threaded I will have to have ACE hardware thread it, they are the only ones with a pipe threader that can thread short nipples I can't buy.

 

[nybirdman]

Same background and experience as you. Your procedure is for a powerhouse, not someones basement boiler.

How would you suggest he weld it then?

 

[chuck172]

6010 all the way out. As long as there is no cast involved.

 

[kencunningham]

If the pipe is welded it should be marked A53 grade A or B. If it is seamless it will be marked A106B, this is for carbon pipe only. The beveled end weld caps are made to welded on the pipe so no worries there, they are stamped from flat stock and not cast.

 

[Arc weld]

I was just making sure it wasn't the pipe you buy at Home Depot.

 

[Tractor Seabee]

Welded seam pipe is okay to use for the low pressures of the OP's project. FYI- A53 seamed pipe is identified as grade A or B and Class F. A53 is also made in seamless and is Class S. A106 is only made in seamless. This data comes out of ASME B31b Code for power piping. Standard practice today is to use socket weld forged fittings for 2" and smaller and butt fittings on larger. All SMAW. OA is pretty much a thing of the past.

Interesting side issue: I once worked for an industrial refrigeration contractor that was always cutting corners on materials. Big ammonia cold storage plant he bought a batch of Italian made seamed pipe (sold as A53 but no markings). We put the hydro test of 300 PSI on it and most of the seams opened up, not even fused all the way through. There went his savings plus his profit on that job.

Ron

 

[Jorville]

I was just making sure it wasn't the pipe you buy at Home Depot.

Arc Weld, No home Depot This is A53 grade B domestic, American made. I could have bought Turkey made pipe for $17.00 less from a steel yard. The pipe I bought came from Columbia pipe.