Welding Lean Duplex Stainless Steel AL 2003

Date 04-19-2008 07:59

Rick,
Cut and paste this link below.
http://www.alleghenyludlum.com/ludlum/search/queryresults.asp
If it doesn't work go to www.alleghenyludlum.com and type welding procedures in the search.

Not sure about GTAW but have spent the last 6 months working with this material (SMAW, FCAW & SAW) and the contractor I was supervising has sworn they will never bid on another lean duplex job again.
We had huge nightmares but that was more to do with the contractors performance than the actual material.
Regards,
Shane

By js55

Date 04-21-2008 14:29

Shane,
What problems were they haveing. The whole idea to lean grades is to have an alloy that is easier to weld in services where more highly alloyed duplex's are not necessary.
I have seen situation where lean grades were spec't where a higher alloy probably should have been used and then to save money (or as so often happens materials guys dump problems on welding guys and then pat themselves on the back for saving money) more robust welding specs were imposed to make up for it.

By Shane Feder (****)

Date 04-22-2008 07:54

Hi Jeff,
If you have a look at "Welding Lean Duplex" in the Search Engine there is a very detailed discussion between yourself, Chuck Meadows and John Baxter regarding Duplex FN numbers. John is my boss and I was sent to the Philippines for 5 months to try and sort out the welding problems on the AL2003 panels. We had 6 off 70 metre diameter sulphuric acid storage tanks to build so there was a huge amount of welding involved.
FCAW using E2209T1-4 gave us quite consistently low FN numbers, late 20s to early 30s when the project minimum requirement was 35 so where it was in contact with the product the cap was removed and replaced with SMAW or SAW.
Regards,
Shane

By js55

Date 04-22-2008 14:15

Shane,
Let me go back and reference that thread to refresh my memory which isn't near what it used to be.
If you don't mind my asking, what levels of FN did you get on your PQR quals. And did you use the same FCAW wire?
Did you do any corrosion testing for your PQR?
And I just wonder if you would see any difference at all in mechanicals or corrosion test results with 7 or 8 FN difference (say 35 down to 27). Sometimes specifications lose sight of what the FN is really all about. Not always, but sometimes.
It does almost sound like a 'save on materials let the weld guys work a little harder' scenario. Which I believe is very common in duplexes. Understandable given the cost of materials and the economy of welding.

By Shane Feder (****)

Date 04-22-2008 14:59

Jeff,
We (the client) didn't witness the PQRs, they were done in the USA but apparently they recorded 40FN on Side 1 and 44.2 FN on Side 2.The wire used for the PQR was ESAB 2209T1-4 and Alloy Rods 2209T1-4 was used in fabrication. It was a while ago but if I remember correctly ESAB bought out Alloy Rods (or they amalgamated) so it was supposedly exactly the same wire, just in a different box.
Tests performed were bends, tensiles,impacts,vickers hardness,brinell hardness, FN Point Count (E562-95) and corrosion x 2 (ASTM G48 A).
Everything supposedly passed fine (all the testing was in-house) but when we tried to reproduce in production (and when we tried to run a couple of repair procedures in the Philippines) we had totally different results.
Regards,
Shane

By js55

Date 04-22-2008 15:13

Shane,
I am assuming your repair procedure results were more consistent with what you experienced in the field?
Did you do a G48 on your repair PQR?
Did you run an E562 on your repair PQR or the same method used in the field?
I know this has been awhile for you and we certainly ain't gonna solve it here but its a good discussion.
Do you remember any noticable heat input differences between the PQR data and the field?
You said these were tanks. So, the field welds were vertical/horizontal? The PQR coupon flat?

By Shane Feder (****)

Date 04-22-2008 15:40

Jeff,
Don't remember all the technical info (John Baxter looks after that side of things) but I do remember that repair coupon after repair coupon failed for one reason or another.
The original PQR was done in the 3G position, the only difference was they ran the first pass vertical down in the PQR and we were running the first pass vertical up.
We had a huge amount of repairs on the SAW that were repaired with FCAW and failed ferrite testing.We put that down to excessive interpass temps because they had inadequate supervision and they were doing run after run in the 2G position without letting it cool down between runs.
80% of the defective welding had been done before I arrived and trying to get answers out of the contractor was like getting blood from a stone, we just had to guess what they had been up to.
Definitely an eye opener for me and the client, maybe next time they will put an inspector there from the start and avoid all the costly rework.
Regards,
Shane

By js55

Date 04-22-2008 16:35

Shane,
Actually, I think you've hit the nail on the head with the cause. In light of no WPS controls then high heat input and excessive interpass temps (get it done-get it done), allowing for more time for transformation to austenite (since duplex solifdifies as ferrite) would reduce FN. A typical 'lack of production control' problem.
Blood out of a stone. :) I hear ya.

By Kix

Date 04-25-2008 14:30

All I know is that stuff is a pain to purge with that 95/5 argon/nitrogen mix. You'd get the O2 level on your meter way down almost to 0 and fire up in the joint and when you checked it, sugar was what you saw. Sometimes the roots went in good and sometimes they sugared and I never could find out why. I even welded the procedure test coupon and it wouldn't hold a purge for sit either. I'd get a good root going and out of say 5 inches of root you'd have about an inche in the middle that was sugar. Out of everyone welding this stuff on the job not one person went trouble free. A lot of guys were busting x-ray because of sugaring probs. I had to check every inche of my roots to make sure they didn't sugar through the little window left at the top. Never busted out so I guess that last part always went in good.

By js55

Date 04-25-2008 15:00

Just an anecdote. I was working the Geothermals in the California desert many many moons ago. We were runnin a ton of SS. Everyone was having purge problems. We'd all do the displacement calcs, O2 measurments etc., runnin the gas slow and form the bottom, double check the integrity of our dams, and then some. It helped but not elimitated. 1 hr, two hours we'd purge, dams as close as you could get em, and still fight the miserable thing for the rest of the day. Most of it being 12" or larger.
Then one old boy that had seen a thing or two I suppose, did it different. He purged for almost 10 hours. Stood around for most of the day waiting. Then towards the end of the shift he zipped his root in clean and pretty as you please run a cover, packed up his lunch box and hit the bus, finishing it the next day.
Go figure. Sometimes the science gets tossed out the window and you just need to know something.

By maringan_htgl Date 05-17-2008 01:56

Hi Rick,

I hope the welding guide in the link below will help your problem

http://www.avestawelding.com/3756.epibrw

Maringan