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Up Topic American Welding Society Services / Technical Standards & Publications / Vertical MCAW and Prequalified WPS
- - By Lawrence (*****) Date 02-25-2009 15:54
Against my advice, a local fabricator would like to run Welder Performance Qualification tests on limited thickness grooves with MCAW on plain carbons steel in the Vertical position with downward progression.

D1.1   Clause  3.7.1 (1) & (2) tells me that all welds other than repair of undercut and tubular products must be run Vert with upward progression if the WPS is to be prequalified..

I'm looking for validation from the forum before I tell this person that if they elect MCAW and Vert down, that they will need to fully qualify any procedures per section 4.

Am I on solid ground here?
Parent - - By BryonLewis (****) Date 02-25-2009 16:19 Edited 02-25-2009 16:32
Try this one Lawrence D1.1:2008 3.2 covers Welding Processes. MCAW is not included in 3.2.1 Prequalified Process or 3.2.2 Code Approved Processes.  It would fall under 3.2.3 Other Welding Processes.  "Other welding processes not covered by 3.2.1 or 3.2.2 may be used, provided the WPSs are qualified by applicable tests as described in Clause 4."

I would think that based on the non prequal status of the process that it would have to be qualified regardless of progression, no?
Parent - - By Lawrence (*****) Date 02-25-2009 16:40
Bryon

GMAW and MCAW are synonomous for Prequalified WPS

Check Table 3.1

MCAW fillers are noted right with GMAW... See (E70C-XC)
Parent - By BryonLewis (****) Date 02-25-2009 16:54
OOPS!
Parent - - By hogan (****) Date 02-25-2009 16:40
IMO any downward progression, if to repair undercut or completely weld out a joint, requires qualification per AWS D1.1. The code is just stating that it can be done. It is not relieving the fabricator of any other provisions.
Parent - - By Lawrence (*****) Date 02-25-2009 16:46
Right

This guy wants to qualify welders and run production (structural) with MCAW with spray transfer and Vert down..

I don't like the notion for a gillion reasons but am looking for specific code language to back my assertions.

I'm hoping that once he sees the trouble that PQR's present he will rethink the idea to control his process in production in a way that provides for flat and horizontal fillets and removes Vert and overhead spray transfer welds altogether.
Parent - - By hogan (****) Date 02-25-2009 16:54
D1.1 (08) table 4.12 (5)
Parent - By Lawrence (*****) Date 02-25-2009 18:38
Thank you fellows for validating my conserns!

Now let's see how convincing I can be to help this guy along his way.
Parent - - By Kix (****) Date 02-25-2009 17:33
Unless he is welding on a tubular applications then he must qualify a procedure no matter what process he is using to go vertical down.  Run some fillets and and break them to show this guy that he is asking a lot.
Parent - - By 803056 (*****) Date 02-26-2009 13:37
As Lawrence mentioned, metal cored electrodes are currently a subset of GMAW. However, the latest revision of the filler metal specifications is regrouping the metal cored (cored electrodes in general) with the FCAW filler metal specifications.

I would expect that the construction codes will follow suit and consider welding with metal cored electrodes as FCAW in future editions.

Downward progression, I love it! They have been doing it for years in the cross country pipeline industry, but then again, they don't have to meet AWS structural acceptance criteria do they.

I hope you are charging by the attempt. "There's gold in them thar hills" Lawrence!

Good luck. Sometimes your client has to learn by "doing", no amount of free advice will deter them. After they spend a few thousand dollars the light will come on and they will seek your council on the matter.

Best regards - Al
Parent - By jwright650 (*****) Date 02-26-2009 13:47
"Sometimes your client has to learn by "doing", no amount of free advice will deter them. After they spend a few thousand dollars the light will come on and they will seek your council on the matter. "- quote

Funny how that works, isn't it Al?
Been there done that too....I had a small fabricator who had guys couldn't pass a GMAW welder 1" plate qualification test, even after they called and asked my opinion about chipping the silicon islands for each pass, they continued with the practice of trying to float them out with subsequent passes. After many attempts, they went back to chipping those little silicon islands out on every pass, and they were simply amazed that they were now passing these qualification tests.
Parent - By Lawrence (*****) Date 02-26-2009 14:29
Al,

In my part of the country I'm literally surrounded by small players who are still using 045 solid wire 75/25 and running vert down in structural production..

One by one they come and ask about "Certifying" their staff..  (which usually is 1-3 welders)...  Once in a while the salesman will talk them into some of that fancy Metal core stuff,,,, Extravigant promises are made as to production rates and quality improvement... "Well the guy said MCAW was a spatter free process!"

And of course MCAW "can" be spatter free... Just like solid wire if it is run correctly  :)

And I don't mind doing my part to help strengthen the local economy and the players that keep it going, lots of free consulting phone calls... Those employees are my former students.. In a couple of years those student/employees will be the decision makers in those plants and then I'll get some traction!!!!!!!!!!!!!
Parent - - By James Corbin (**) Date 02-26-2009 18:54
Wow!! That is the first time I heard that one.
Does that mean they will change the MCAW specification from A5.18 or A5.28 to FCAW A5.20 or A5.29 as well?
I was kinda hoping they would split up FCAWg from FCAWs and GMAWsp from MCAWsp for testing purposes (4 separate WQTR tests showing skill for each one seperatly)
Parent - - By 803056 (*****) Date 02-26-2009 19:59
My comments are based on what I've heard, so take it with a grain of salt.

It is my understanding that the metal core electrodes are moved to A5.20 and A5.29 with the release of the next edition of each.

I never fully understood why they were grouped with the GMAW electrodes to begin with.

I don't think you'll see the gas shielded (GS) and self shielded (SS) FCAW electrodes separated any time soon. My experience is that a welder qualified with either GS or SS can use the other without any problems.

Best regards - Al
Parent - - By James Corbin (**) Date 02-26-2009 23:57
I can see why GMAWsp and MCAWsp are together, no flux. But I also can see FCAWg and FCAWs separated.
I have weldors that can run FCAWg and still CAN"T pass a test in FCAWs.
My field weldors tried to go from running E7018 and test out for FCAWs saying it can't be that hard and did not come even close, even after days of showing them how to set up the machine and run it. When I set up the feeders / machine and would not let them touch the dials a few of them did finally figured it out. It was LOL to watch them. Then when they were on their own...........well................"its wire's fault"..........Yea - Not hardly. I even made them cheat cards with all the correct settings.
I then showed a few of them FCAWg and an hour later could pass a test plate, but I don't want them welding moment connections if they can't pass a test with the innershield. (My choice)
Parent - By 803056 (*****) Date 02-27-2009 21:07
The very first time I ran a test with self shielded FCAW was the welder qualification test. The foreman asked me if I had ever run FCAW and I replied, "Hell yes, that's all I've ever done!"

He responded, "Good the test plates are on the bench. You pass you stay, fail you go!"

Luckily I passed, but I didn't find it that difficult to weld in the flat position. There was a learning curve for welding verticals!

I always recommend that the welder be tested using the electrode material to be used in production. It is less expensive to iron out any skills problems on the bench than it is to repair production welds!

Best regards - Al 
Up Topic American Welding Society Services / Technical Standards & Publications / Vertical MCAW and Prequalified WPS

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