Welding 3" Thick 347 SS to Carbon Steel
Welding 3" Thick 347 SS to Carbon Steel
(OP)
Hi Guys,
I have a job coming up that requires us to weld 3" thick SA182-347 to SA106 Gr. C Pipe. I am no metallurgist but I have read enough in here to scare me a little with regards to Re-Heat Cracking on thick sections. I am not sure if this is a major factor but the design temp for this joint is 550°F
My Plan at the moment is to butter the CS weld bevel with ERNiCr-3 and then PWHT the CS pipe. I then plan to weld the joint with ER347 in a similar manner to a standard 316 or 304 joint.

Is my plan flawed and doomed to failure?
If so, can some kind sole please suggest a better approach.
Many Thanks
I have a job coming up that requires us to weld 3" thick SA182-347 to SA106 Gr. C Pipe. I am no metallurgist but I have read enough in here to scare me a little with regards to Re-Heat Cracking on thick sections. I am not sure if this is a major factor but the design temp for this joint is 550°F
My Plan at the moment is to butter the CS weld bevel with ERNiCr-3 and then PWHT the CS pipe. I then plan to weld the joint with ER347 in a similar manner to a standard 316 or 304 joint.

Is my plan flawed and doomed to failure?
If so, can some kind sole please suggest a better approach.
Many Thanks





RE: Welding 3" Thick 347 SS to Carbon Steel
That is the correct basic approach.
But the risk is in the details.
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P.E. Metallurgy, Plymouth Tube
RE: Welding 3" Thick 347 SS to Carbon Steel
I was planning on putting a minimum of 1/4" overlay/butter on the CS weld prep.
Do you think that is adequate?
Thanks
RE: Welding 3" Thick 347 SS to Carbon Steel
RE: Welding 3" Thick 347 SS to Carbon Steel
I am afraid I have already purchased 160lb of 347 weld wire.
Is there anything I can do during welding that will reduce the risk of cracking if I use the 347 weld wire?
Thanks again.
RE: Welding 3" Thick 347 SS to Carbon Steel
If the pipe was supplied in a fully solution annealed condition or had a stabilization treatment, welding should not be a problem after the butter layer and PWHT have been performed on the carbon steel side of the weld joint, as long as the delta ferrite level is acceptable to avoid hot cracking.
I would hope you are qualifying a welding procedure specification for this project.
RE: Welding 3" Thick 347 SS to Carbon Steel
Checking your FN on your filler is a first step.
Watching heat input and temperatures is critical.
You are doing a full thickness qualification, right?
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P.E. Metallurgy, Plymouth Tube
RE: Welding 3" Thick 347 SS to Carbon Steel
Metengr/Ed,
I will be qualifying the WPS next week. The actual material that will be used for the job is a forging and not pipe so I am hoping that it will be supplied in a fully solution annealed condition.
Due to the very short lead time on this I have had to make do with 1 1/2" thk plate for the PQR.
Guys, I really do appreciate the time and thought you put into your answers.
Many Thanks
RE: Welding 3" Thick 347 SS to Carbon Steel
RE: Welding 3" Thick 347 SS to Carbon Steel
RE: Welding 3" Thick 347 SS to Carbon Steel
Watch this when you do your qual, you need a pass schedule that minimizes the dilution of the 347 by the Ni.
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P.E. Metallurgy, Plymouth Tube
RE: Welding 3" Thick 347 SS to Carbon Steel
Now I am more confused (not that difficult to do). Would it be better to use a 309 wire for the buttered layer?
Thanks
RE: Welding 3" Thick 347 SS to Carbon Steel
RE: Welding 3" Thick 347 SS to Carbon Steel
I just wish I had started this post before buying the consumables.
If anyone is interested, I will post the results of the testing after completion.
Thanks again to all for the contributions.
RE: Welding 3" Thick 347 SS to Carbon Steel
A recent example of welding ER347 into a ENiCrMo-3 weld overlay to weld 347 internals to the heavy wall carbon steel overlayed vessel. The ER347 was specified by either the manufacturer's Welding Engineer or the Engineering Company. Regardless or who specified it, the welds could not be completed without cracking after numerous repair attempts. For this weld, I would have recommended the use of ERNiCrMo-10 or ERNiCrMo-3. While I had no involvement with this vessel, I did casually mention the improper choice of filler metal and they finally made the welds correctly - after 5 months of failure.
RE: Welding 3" Thick 347 SS to Carbon Steel
I am not really sure about the mechanism of the cracks that I could possibly encounter. Is the concern with cracking in the Weld Metal or will it be along the HAZ or Base Metal?
Thanks
RE: Welding 3" Thick 347 SS to Carbon Steel
RE: Welding 3" Thick 347 SS to Carbon Steel
I presented my preWPS to our customer, 309 butter on the carbon steel and 347 fill and cap to complete the joint. Their response was that they want the full joint welded with 309. They explained to me that this is how their last spool was welded by a previous supplier and they want to keep consistency.
As I mentioned before, I'm not a metallurgist so I am not sure if there is any metallurgical reason to avoid this.
Ed, Stan and Metengr, do you know of any reason why 309 filler would be a poor choice for this complete joint.
Thanks
RE: Welding 3" Thick 347 SS to Carbon Steel
RE: Welding 3" Thick 347 SS to Carbon Steel
I really do owe you a beer for all your help. :)
RE: Welding 3" Thick 347 SS to Carbon Steel
If this was something that saw rapid temperature cycling then I might worry (difference in thermal expansion) .
Watch the temps and you will be fine.
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P.E. Metallurgy, Plymouth Tube
RE: Welding 3" Thick 347 SS to Carbon Steel
Your help is appreciated.
RE: Welding 3" Thick 347 SS to Carbon Steel