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Up Topic Welding Industry / General Welding Discussion / Welding inconnel and hastelloy pipe?
- - By Irv Ayers (*) Date 02-06-2011 02:48
I've been welding for 10yrs. now and recently landed a fitting job welding with GTAW, SMAW welding process on stainless, carbon, and aluminum pipe. I am certified on carbon pipe and stainless pipe but never welded hastelloy or inconnel. There's going to be a pipe job coming up welding hastelloy and inconnel and just wondering if either of them weld anything like stainless steel or not? I heard different opinoins from people I've talked to. Can someone give me some advice? Never touched the stuff when I was in welding school.  Thanks.
Parent - - By JeremyW83 (***) Date 02-06-2011 03:09
Both are nichol based and have to be purged like stainless steel.  but the wire feeding technique that I use is different than with SS.  I do a wierd dabbing method that I learned from an older welder.  plus the heat is a little higher.
Parent - By Irv Ayers (*) Date 02-06-2011 14:06
Thanks, I will try that wire feeding technique.
Parent - - By Irv Ayers (*) Date 02-06-2011 17:45
Another question that I forgot to ask. Do either of these have to be post heat treated to relieve any stress?  Thanks for your input..
Parent - - By Tommyjoking (****) Date 02-06-2011 18:11
Never done any SMAW on Hastalloy.  Inconel is not much diff from stainless welding, if you can run a few beads on some drop pieces you will master it easily.  Hastalloy on the other hand has some very sluggish puddle qualities to it, seams to weld "dirty".  You will have to use a care full preheat/cooldown process with it as well, full purging is very important.  Contamination is an issue as well, completely new and separate brushes etc. are a MUST.  Hopefully this will be fully engineered work and have a solid WPS for you to work from.  I have not done much of it, always had a WPS in a controlled shop, but there are quite a few experts on the alloy here, hopefully they will throw in some good advice.
Parent - - By Irv Ayers (*) Date 02-06-2011 18:38
Thanks. I do know that the weld process will be done with GTAW all the way out. All of the info I have gotten from here is going to be very useful.
Parent - - By js55 (*****) Date 02-07-2011 16:14
Open the bevel. Use feather edges and watch them closely for good fusion with GTAW. The puddles are viscous.
Don't try to get better puddle characterisitics by increasing amps. It doesn't work. Don't carry a puddle with SMAW. Run it with stringers.
Parent - By 803056 (*****) Date 02-07-2011 21:49
Nickel is one alloy family where weave beads are a definite "no-no." Look who’s saying not use weave beads!

The oxide on the surface is very tenacious and must be removed by abrading each bead with a grinding disk, clean file, or carbide rotary file before depositing weld over the previous weld bead.

Do not use preheat and maintain a low interpass temperature. Surfaces should be dry, but allow to cool until warm to the touch if you need to warm the surfaces to dry moisture before welding. 

Clean the inside of the pipe to remove oxides (use an abrasive wheel or carbide rotary file) and wipe down with solvent soaked rags. Cleaning should extend at least 1 inch from the toe of the weld. Tape all joints until you are ready to weld and then peel the tape just before welding. Don’t leave the tape on small diameter pipe (4 inch or less).  Scorched tape will produce CO and CO2 that will contaminate the weld pool. The purge gas should be argon and the flow sufficient to reduce the oxygen and nitrogen to less than ½ percent. The system must be free of moisture as well. Heavy oxide deposits on the root surfaces are a sure indication of insufficient purge. The root surfaces should be silver if the purge is performed properly.

Use clean rags and clean acetone or MEK (you can still get MEK, right?) to wipe the joints before welding. Sulfur, phosphorus, lead, zirconium, and boron will result in cracking problems. Do not use “rent- a-rags” for cleaning. The solvents used by the cleaning company may contain harmful chemicals that will cause the nickel alloys to crack.

The weld pool is very sluggish and does not wet in. It can be described as like welding with toothpaste. You have to put the weld where you want it.

Best regards - Al
Parent - - By Jenn (***) Date 02-09-2011 15:04
I weld Inconel and Hast X daily. Al's advice is dead on. Purge purge purge, make sure everything is clean (ground, and chemical/residue free). I would also recomend letting it cool between passes, both of these metals start to act real funky if you get it too hot. Your puddle just goes awry on you.

To me, a puddle is a puddle. I don't see the huge difference really between this and stainless besides it being just a bit more sensitive.

Regards

Jenn
Parent - By Metarinka (****) Date 02-13-2011 18:22
everyone had good advice, hastelloy and inconnel are very sluggish, a little more sensitive to cleanliness and oxidation and can't be made wetter by increasing the heat input.  The penetration power is a little less so it's usually wise to open up bevels use smaller lands or wider roots, but it doesn't run too different from stainless steel.

That being said if the material is clean and the prep is right, it's very easy to weld.
- By Irv Ayers (*) Date 02-14-2011 01:27
Hey all of your guys advice really helped. I cleaned the pipe well, used knife edge with 33-35degree bevels and got great root penetration. It does have simularities as stainless steel (inconnel that is.) Cleaned each weld pass and let it cool as well. And I purged, purged, and, purged. Don't know when I will be doing the hastelloy though but I did some weld beads on a piece of scrap pipe and the puddle is very different. Just something I will have to get use to when the time comes.  Thanks for everyones help on this.
Up Topic Welding Industry / General Welding Discussion / Welding inconnel and hastelloy pipe?

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