D1.1 vertical tacking

By rjtinsp (*)

Date 06-25-2014 18:36

Wouldn't a WPS for fillet welds cover tacking? A tack weld in most cases is a fillet weld.

Ramon

By Lawrence (*****)

Date 06-25-2014 19:04

Right,

But all my fillet WPS's are for 1F or 2F,

Can I just generate a prequalified 3F GMAW Spray transfer WPS?

Maybe my old head is just foggy.... Since it's pretty much impossible to run a full length vertical fillet with Spray GMAW it seem silly that I could write a prequalified WPS for it.... But Table 3.8 does not restrict I guess... Nor does Clause 3.9 say anything about position...

Perhaps I'm overthinking this?

By jwright650 (*****)

Date 06-25-2014 19:20

<Since it's pretty much impossible to run a full length vertical fillet with Spray GMAW
You only have to make it 2" before it falls out :razz:

(Fig 4.39)

By Lawrence (*****)

Date 06-25-2014 19:46

So John,

You would be comfortable scribbling a prequalified Vert-up WPS, tack testing your welders to it and then let them go into production?

I mean really?

Is it that easy?

By jwright650 (*****)

Date 06-25-2014 20:12

Well I really haven't given much thought to it....the shop I was in for nearly 30 years used electrodes that could be used in the 3F position(unlike GMAW spray). I would hate to have to go through the trouble of qualifying a WPS just to test tack welders...I understand that these tack welds will most likely get melted when the final welds are placed...maybe you could use an electrode that can be used out of position for tacking and then you could meet code requirements without defying the laws of gravity.

By js55

Date 06-25-2014 20:27

Why do they have to do spray for tacking?

By Superflux (****)

Date 06-25-2014 20:56

This is far beyond my realm of expertise, but thinking it out beyond the obvious I came up with this...
YOU are setting up the test parameters, correct? I do not recall anywhere it is mentioned in any code that the current MUST be applied continuously (non-stop) during the test or production welding for that matter.
Write up the WPS to be performed "intermittently"... as in "zapping". This is just a "Tacking Test" any ways right?
Pull the trigger, pause, and continue. Find the settings (and cool down time), run a few samples and see what happens.
After all, aren't tacks to be removed prior to welding (per many specs) unless it is submerged arc?
Just brain storming here and tossing out SWAGs.
My current gig set up a simple qual test for a few chosen helpers to perform tacks since our spec requires all tacks on fillet welds to be ground out prior to final welding.

By Superflux (****)

Date 06-25-2014 21:05 Edited 06-25-2014 21:10

js55,
I am guessing that the machines available on the production floor are preset for spray xfer and probably not in the best interest to be jacking with settings on too dramatic of a change. Besides, gas compositions can vary between modes of transfer.
It's too easy for a complacent welder to grab and go, therefore messing things up and creating rework. Production welders often get to be Robot-like in their habits and don't react well when the conveyer belt skips a cog. And then there's all that whining when extra steps are added in.
Engineers Love change (they often get bonuses for changing things!) , Welder's on the other hand tend to Abhor change.

By js55

Date 06-26-2014 12:04

Super,
Depends on how the production floor is set up. If the short circuit is in fit stations then there is no issue of confusion.
And actually I would be more concerned about a welder so complacent as to not be able to distinguish a spray set up from a short circuit set up. Or not care.
If you have a worry about such basic things as that about your welders, it will manifest somewhere else. In other words, the problem is not the set up. Its the welder.
I certainly understand the habitual nature of welders having been for a long time. However, neither are they stupid.

By Superflux (****)

Date 06-26-2014 13:48 Edited 06-26-2014 13:51

js55,

The past four years I've primarily dealt with welders under Socialists regimes in foreign lands. They have NO incentive to advance. They have a job and social status in the community and cannot be fired short of murder on the jobsite. It seems every day is training day all over again. I often feel like Bill Murray in the movie "Groundhogs Day". Sometimes my comments reflect this experience of having a very low opinion of welders.

By js55

Date 06-26-2014 15:10

Super,
I understand. Spent time in Venezuela. Very similar. We had to deal with a situation where they had money building up in a fund for layoff.
Fired. Layoff. Didn't matter.
After awhile they wanted to be fired to get the big payoff. Talk about difficult to deal with.
10-20k was a lot of bolivars.

By jwright650 (*****)

Date 06-26-2014 11:05

>Why do they have to do spray for tacking?

Jeff, I think the idea was to not have to qualify a WPS just to test a few tack welders(a lot of trouble and expense for just tacking out of position). Using Spray in D1.1 is prequalified, Short Circuit is not.

L,
Is it out of the question to allow the fit-up guys to tack with an electrode that is capable of running uphill 3F? This would allow them to assemble without having to roll or turn the assembly as much until they are ready to weld it out.

By js55

Date 06-26-2014 12:10

John,
I understand but my approach was that the reality of trying to make the spray fit in this case is the greater of two evils.

By 803056

Date 06-25-2014 22:29 Edited 06-26-2014 14:32

I'm shooting from the hip this afternoon. I don't have my D1.1 with me, so here goes nothing.

1) Welding must be done in accordance with a WPS that may be prequalified or qualified by testing.
2) Only vertical uphill progression is prequalified. If one wants to use down hill progression, it must be qualified by testing.
3) Tack welds that are incorporated into the final production weld must meet the visual criteria of D1.1 unless SAW is used for the final production weld, in which case there are separate criteria for undercut.
4) Welders must follow a WPS when welding their qualification coupon. I assume that also applies to welding operators as well as tack welders.
5) There is no differentiation between qualifying a WPS for the production weld or the tack weld, since if the tack weld is incorporated into the final weld, it must meet all the requirements of the production weld.
6) Progression for vertical welds is an essential variable when qualifying the WPS by testing.
7) With the exception of SAW, rarely is the tack weld completely consumed by the production weld. Ask any one that reviews radiographic film. It is usually easy to see where the tack welds were located if the ends of the tack welds were not feathered.

Tack welds made using GMAW-spray transfer using vertical uphill progression? I don't think so.

Here is a photograph of a couple of welds made using the technique mentioned, i.e., vertical uphill progression using GMAW-spray transfer. I would not accept these welds whether they are called tack welds or production welds. The proof of the pudding is the break test. No fusion in the root and incomplete fusion between “blobs.”

I asked the welder, "What the hell are you doing?"

"I'm pulse arcing." was the reply.

Best regards – Al