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Up Topic Welding Industry / Technical Discussions / FCAW-G Super Duplex Stainless Gas inclusions?
- - By MRWeldSoCal (***) Date 04-24-2013 17:20
Welding on some ZERON 100 Super Duplex and when I weld verticle I cant seem to shake the rough cap.  It is either over textured or I will get what ive been told can be a gas inclusion.  I only run into this problem in the verticle position.  Running it with a miller 450MPA and ESAB Shield Bright 2594 .045 wire.  Went from originally running a 75/25 argon CO2 mix to a 90/10 mix that made the arm more stable but still have the issue.  CFM on the flow meter is at 35-40.  Any thought?
Attachment: ESABFluxcoreverticleadjustedsmall.JPG (72k)
Parent - - By ozniek (***) Date 04-25-2013 00:59
Hi

Have you RT'ed any of the joints? I ask because we have had a similar problem, but we were getting porosity when welding in the overhead position with SDSS FCAW wire. (During PQR qualification tests.) When I did some research, I found that porosity in the OH position is typical of these fillers. Does pass code acceptable limits though, but still more than makes me comefortable. I notice that you mention using a 90/10 mix. The specs generally call for a 20 - 25% CO2. Apparently if the CO2 percentage gets below 15%, it can lead to problems, so you may want to look at that. Some other issues that we had while using the wire:

1) We were using a fancy Miller power source, and the welder had it set on the GMAW setting. On this setting, the power source does unexpected wave shaping, that appears to not be beneficial for FCAW. Make sure you have the power source on the FCAW setting.
2) The flux appears to be very fluid, running down the filler wire and causing an unstable arc. Try to get the arc as far to the front of the puddle as possible, and travel faster. This may leave a "ropey" bead, but this can be countered by a rapid but small "weave" motion.
3) Make sure your wire stick-out is as per manufacturer's recomendations.

Keep in mind that to get the right properties from the SDSS, you need to have a very low heat input. With higher heat inputs you will not be able to pass the required impact and corrosion tests normally required when welding these materials.

Hope this helps.

Regards
Niekie
Parent - - By Superflux (****) Date 04-25-2013 12:04
Maybe a "Tri-mix" with some substantial amounts of helium might float up there for better coverage on overhead???
Parent - - By Superflux (****) Date 04-25-2013 12:12
35-40 CFH might be a bit too much and causing turbulence, back draft thereby sucking air into the zone.
Also, sometimes I/we have had to deface the nozzles/cups (stuck in a vise and bent into an oval shape) to get proper stick-out and into the joint.
Gun angle can get complicated too...
Parent - - By MRWeldSoCal (***) Date 04-25-2013 14:18
Yea were trying to not run a tri mix for Helium usage purposes.  The project were getting started on is a massive one and according to our esab guy we shouldnt need it at all.  Also were trying to not make the process too difficult with too much technique.  We are trying our best to dumb down the welding since we already have to do GTAW roots in all the piping connections.  As for travel speed, that photo was moving pretty fast, I mean I was just staying afloat with out my base metal stepping out and it was the size and width I was looking for.  I looked into gas defects and lincoln says that its can be the situation and the fast drying slag not allowing it to release.  Ive heard it all the way down to preheating the wire, to removing aany condensation on the base metals.

As for new things besides this, since there really are no rules on this stuff and no one has the time or $$ to play around with it, I switched it to (MIG) pulse spray transfer mode and holy moly did it rip!  took on a whole new beast and laid incredible welds... the ESAB guy didnt know what to say... Just that he was never trained for this hahah

I thought the gas flow might have been a little high also... much more practice tomorrow
Parent - - By Superflux (****) Date 04-25-2013 18:37
" Ive heard it all the way down to preheating the wire,"
Perhaps an increase in base metal preheat?
Give those off gasses some time to "cook out"?
Parent - - By ozniek (***) Date 04-26-2013 03:09
Hi Superflux

With SDSS you do not really want to increase the pre-heats. Generally welded without pre-heat, and interpass temps must be kept to below 125C. Also need low heat inputs. This all conspires to increase porosity.

Regards
Niekie
Parent - By Superflux (****) Date 04-26-2013 13:01
ozneik,

Ooops! Nice catch as I had a cranial cramp and forgot this was indeed an SDSS.
It's what I get for letting the fingers do the thinking.
Parent - - By ravi theCobra (**) Date 04-25-2013 16:05
Tri mix  is   90  %  Helium      -  How much richer do  you want to  go   ???????????????
Parent - By MRWeldSoCal (***) Date 04-25-2013 17:33
I dont want to use Helium with how hard it is to get, this project is going to requre a lot of gas shielding anyways.  Just trying to trouble shoot the gas defects on the surface.
Parent - By MRWeldSoCal (***) Date 04-25-2013 17:35
And again this is only on my Verticle Up...    Flat and horizontal are totally fine and the slag just falls right off
Parent - - By Superflux (****) Date 04-25-2013 18:40
Ravi,
"Tri mix  is   90  %  Helium      -  How much richer do  you want to  go   ???????????????"
Until all the welders on the floor talk like Donald Duck?????
Parent - By jwright650 (*****) Date 04-25-2013 18:58

>"Tri mix  is   90  %  Helium      -  How much richer do  you want to  go   ???????????????"
>Until all the welders on the floor talk like Daisy Duck?????


Fixed it for ya :razz:
Parent - - By MRWeldSoCal (***) Date 04-25-2013 19:20
Tomorrow will be the judgement day for this, we have ran successful PQR's for tig 3/8 plate  with a 98-2 argon nitrogen top gas and purge gas... then did a solid wire 2G with pulse spray and that also passed... We were worried the flux core wouldnt pass the G48 corrosion test but I think it will.  Just cut the 3/4 plate for this next round and were going to run it 2G so im sure all will be well.   Its funny cause we have all "old school" guys here that think the XMT 450 is the devil and their deltaARC 451 is the only way to go...  So im going to give them a roll of shield bright tomorrow and have them run it their way and see what they come up with.
Parent - By ozniek (***) Date 04-26-2013 03:14
Hi

Keep us updated - I am also interested to see what you come up with. Something else we had a problem with, is getting the FCAW SDSS impacts to pass in the weld metal. What temperature do you need to pass impacts at? What is your application / code?

Regards
Niekie
Parent - By ozniek (***) Date 04-26-2013 03:05
Hi Superflux

Will keep that advice in mind, but I don't think gas coverage could be the problem in our case. I have come to the conclusion that with the FCAW consumables, there is always some gas evolution, but normally the gas bubbles will float to the surface, so not problem. When welding overhead, the gas bubbles are not helped by gravity to head for the surface, so remain in the weld. (My theory in any case.) We decided we can live with this, because most of our welds will be either rotated or 2G, and as I said, the amount of porosity still falls within acceptance criteria, so OK.

Regards
Niekie
Parent - - By Jim Hughes (***) Date 04-29-2013 18:35
MRWeldSoCal,

Back in 2011 we had to qualify a number of Duplex and Super Duplex procedures. One was a S32507 to C.S using E309LMO T1-1/4  0.045. 75%-25%   We had to x-ray and perform to ASTM A923 A,B, and C. I had the same issue. Could not get it to look very good. The finished weld did not look that great. I welded this up using an SA 250D Lincoln. (CC only) I have never showed this picture before, just out of sheer embarrassment. Now that I have seen yours, I’m not so embarrassed. Just kidding. :) I think what you are seeing in the as welded condition if about right.

Jim
Attachment: PB210561.pdf - 2507 (882k)
Parent - - By MRWeldSoCal (***) Date 04-29-2013 18:43
That color is just what I am looking for.  Were about to start the plate, Im not welding it today, one of my guys are...  What position was that plate you did in?
Parent - By Jim Hughes (***) Date 04-29-2013 20:10
MRWeldSoCal,
Since we had to pull charpy's it's in the 3G position.  Also forgot to mention that we were held to 26000 Joules.

Jim
- - By 803056 (*****) Date 04-26-2013 19:17 Edited 04-26-2013 19:35
My guess would be that you are too short with the electrode extension (contact tip to work distance).

The CTWD is one of those important parameters that some codes do not consider. However, the use of too short or too long a CTWD can create all sorts of havoc. Ignoring the CTWD can sink a job pretty quickly. You can usually find the proper range for the CTWD on the manufacturer's product page. ESAB recommends 1/2 to 1 inch for that particular electrode running at 25 to 28 volts and 227 to 567 ipm for wire feed speed. I would start some where around the middle of the recommended ranges. The shielding gas listed is 75% Ar and 25% CO2. A flow rate of 40 to 50 CFH would be the norm for a 5/8 inch gas nozzle.

Nitrogen is an alloying constituent for this alloy. You might want to rethink using nitrogen in the shielding gas or the purge gas.

Al
Parent - - By MRWeldSoCal (***) Date 04-26-2013 19:24
Thank you Al for the information, glad you chimed in on this... Basically both lincoln and ESAB were the supplier for this wire, and It was up to me to choose the better of the two.  The stick out was only loosely reccommended to me and a ranger of 1/4+- which can really be alot.  I was curious about the gun angle also cause they told me 10-12 degrees...  they are cutting the 3/4 plates for the PQR right now, Maybe monday ill run the test.
Parent - - By 803056 (*****) Date 04-26-2013 19:34
1/4 inch electrode extension is fine if you are doing short circuiting transfer with 0.035 inch solid wire. Way too short for the FCAW.

As I said, I would start at the middle of the ranges listed and tweak the parameters from there. I would start with 175 ipm for the wire feed speed, 27 volts, and 3/4 inch for the contact tip to work distance. I would start with the contact tip flush with the end of the gas nozzle. Flow rate; I would go with 45 cfh as a starting point, with no nitrogen.

Best regards - Al
Parent - - By MRWeldSoCal (***) Date 04-26-2013 19:56
The wire manufacturer says 1/2-1 inch stick out... ill give what you said a try on Monday and let you know what happens

Thanks
Jordan
Parent - By 99205 (***) Date 04-27-2013 22:45
Start out with 5/8" stickout and work your way out from there, 1/2" is too short.  I'm thinking that somewhere in the area of 3/4" will work.
Parent - - By ozniek (***) Date 04-27-2013 12:05
Hi Al

Nitrogen is often added to the purge gas and sometimes the shielding gas for GTAW, as it tends to give better corrosion test results. There is some debate if the 2%N is desirable for anything after the root pass, but we have had good experience using it on DSS as purge and shielding gas (For GTAW) all the way through thickness. Having said this, we have also had good results using plain Ar for purge. I have no experience with N in the shielding gas for FCAW, and doubt if it would be beneficial.

Regards
Niekie
Parent - - By MRWeldSoCal (***) Date 04-29-2013 15:00
We have a bottle of 98-2 argon/nitrogen we are using for a purge, either way the PQR will most likely get back welded at the root.  not running any nitrogen on the FCAW shielding gas though
Parent - By cddolan74 (**) Date 04-29-2013 18:59
wouldn't hurt to try another wire. I have used Select Arc product and it comes with pretty experienced guys who work it out with you.
Parent - By Jim Hughes (***) Date 04-29-2013 20:29
Ozniek,
you are correct on the addition of N2 to the GTAW process. It’s mainly due to the depletion of N2 during the welding process. Addition of the N2 will help offset the depletion and help the resistance to, in particular, pitting corrosion.

Jim
Up Topic Welding Industry / Technical Discussions / FCAW-G Super Duplex Stainless Gas inclusions?

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