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Up Topic Welding Industry / General Welding Discussion / WPS
- - By bmaas1 (***) Date 08-14-2008 18:27 Edited 08-14-2008 18:32
All,

I am trying to develope parameters for my WPS.  This WPS will be used for welder qualification.  Here are the parameters I have set so far.

GMAW
3/8" plate A36
single bevel- Figure 4.32 page 180 of D1.1 2006
2G position
.045 ER70S6 wire
23 to 25 volts
290-300 imp wfs
260-270~ amps
Stargon Gas (90Ar, 8Co2, 2o2)
Using push or pull techniques

Are these parameters in the ballpark?  Seems to me the puddle is a little too fluid but that may be caused by the o2 in the gas.

All comments are welcome.

Brian
Parent - By MDG Custom Weld (***) Date 08-14-2008 19:29
When ever we qualify a procedure with a range for volts/ amps/ WFS, we do a PQR for the lower set, middle set (sometimes), and highest set of parameters.  I think you need to specify push or pull, not both.  I'm sure you will have a good smooth profile with one and not with the other.  I also think you need travel speed.  You have two volts to adjust, but only 10 ipm of wire to work with.  You might be able to open that up to like +/- 5%.  We use 5% because it's easy math (+/- 5%=10% total, 10% of 300 is 30 ipm so we can go 285-315).
Parent - - By hogan (****) Date 08-14-2008 19:46
What brand of wire? Are you trying for a spray transfer?
Parent - - By bmaas1 (***) Date 08-15-2008 13:23
I am running ESAB Spoolarc 86.  I am wanting to run somewhere in the transition range for the wire.  I am afraid that trying to run in spray the puddle will be difficult to control in this position.

Brian
Parent - By 803056 (*****) Date 08-15-2008 14:16
Do not use parameters that would cause you to be transitioning between short circuiting and spray transfer. The arc will be unstable and provide unacceptable results.

I would suggest using pulse transfer with SG-AO-2% if your equipment has pulsing capability. I've had excellent results with pulsing in the 2G position.

Best regards - Al
Parent - - By hogan (****) Date 08-15-2008 14:45
bmaas1,
The reason I was asking about transfer is that spray is the only GMAW mode of transfer that is prequalified by D1.1. I've attached a link to ESAB that lists the recommended parameters for the different modes. 803056 has given good advise, but that mode is also not prequalified and requires testing in accordance with section 4. IMO you will want to run in spray pulsed or not.

http://products.esabna.com/EN/home/filler_metals_catalog/filler_metals_product_detail/q/display_id.id44157f8d796843.34215467/category_id.496/path.filler_metals_solid_wire_carbon_low_alloy_steel_carbon_steel_spoolarc_86_er70s6
Parent - - By 803056 (*****) Date 08-15-2008 16:04
Hello Hogan;

I hate to disagree with your comment on spray mode GMAW being the only transfer mode that is prequalified per D1.1.

Clause 3.2.1 accepts GMAW as prequalified except that short circuiting transfer is not prequalified. The three modes of transfer accepted by most people include short circuiting, globular, spray, and pulse transfer. That would indicate all transfer modes other than short circuiting transfer is prequalified.

The other condition (depending on the edition of D1.1 being used) is that the power supply has to be a constant voltage power supply, but that requirement was added in 2004. Any project that references an earlier edition of D1.1 can use any power supply that has pulsing capability. For instance, if the applicable building code states  the welding requirements must meet AISC SCM, the edition of D1.1 could be 1988 for designs that are based on Allowable Stress Design (ASD) or 2000 if Load Reduction Factor Design (LRFD) is used. If I remember correctly, the most recent edition of AISC SCM (13th edition) references D1.1 2004, but few building codes have yet to adopt the 13th edition of the SCM. 

The use of spray mode transfer may be a bit tricky if the groove is in the horizontal position.

Then again, maybe your reference to "pulse spray" and my reference to simply "pulsed transfer" is one and the same. I looked in my copy of A3.0 and didn't see the term "spray pulsed", but there is a "pulsed spray transfer". In the interest of being technically correct, maybe we both should have used the term "pulsed spray transfer" and we would have avoided the confusion.

The main point that I would like to make is that only the short circuiting transfer is not prequalified if GMAW is the process of choice. However, given the position in which the test will be given, pulsed spray transfer is my recommended mode of metal transfer.

I do like your link to ESAB. I use it, and my Lincoln Electric link, whenever I'm in doubt of what parameters to use as a starting point for writing a new WPS. Most pulsing power supplies have "canned" programs for pulsing already installed. The user simply dials in the electrode diameter and the machine's program takes over.

Best regards - Al
Parent - - By hogan (****) Date 08-15-2008 17:22
As usual you are correct about globular transfer. I had neglected to mention that one. It is difficult at best to run in that mode productively. I guess I just don't even consider it as an option when dealing with gmaw. Yes those links are very handy.
Parent - - By 803056 (*****) Date 08-15-2008 17:29
I agree with you on globular!

Do you agree that pulsed spray transfer is prequalified or am I missing something in my reading of D1.1? This wouldn't be the first time.

Best regards - Al
Parent - - By hogan (****) Date 08-15-2008 18:57
As far as pulse being prequalified, I lean to wards no. It can be interrupted either way
Parent - - By 803056 (*****) Date 08-15-2008 19:02
Hogan, my good friend, come on now, get off the fence.

Why don't you believe it is prequalified? ;)  What's is your reasoning?

This could be the start of a good, lively discussion.

Best regards - Al
Parent - By hogan (****) Date 08-15-2008 19:51
But you've had this discussion twice already, that I can remember. I can see both sides of the coin. So the fence it is. Although, at this time I choose to play it safe and eliminate it as a possible future issue by considering it not prequalified.
Parent - By HgTX (***) Date 08-18-2008 14:47
My personal interpretation is that they exclude GMAW-S but nothing else, including GMAW-P.  That means it can be prequalified.  If they meant "GMAW except for GMAW-S or GMAW-P", they would have said that.

Hg
Parent - - By Kix (****) Date 08-15-2008 16:21
I agree with the need to stay in the prequalified category.  You also don't need a trimix gas to achieve spray transfer and could go with a cheeper bi mix.  If you are just doing this for WTQR's then I would deffinetly stick with a prequalified WPS unless your trying to kill 2 birds with one stone for production as well.  There are not to many essential variables for welder performance qualification so you can easily qualify them to a prequalified WPS and have them be qualified for similar WPS's that you needed to qualify by testing later on down the road.  Like Al said, make sure you are in one of the three prequalified modes of trasfer to stay legal.  Do you already have qualified WPS's out on the shop floor?
Parent - - By bmaas1 (***) Date 08-15-2008 16:58
We have prequalified WPS's for this on the floor but never had the need to use them.  I ran a test plate using straight spray mode with 25 volts and 300 amps and a  push travel angle with good results using the trimix because that is just what I had at the time.  We also use 90-10 Ar-Co2
Parent - - By jwright650 (*****) Date 08-15-2008 17:06
Don't forget .....You will need to write a WPS for each of the two gas mixes that you mentioned....because if you change the mix, you can't stay prequalified see Table 4.5(19)
Parent - By bmaas1 (***) Date 08-15-2008 17:15
Yep.  Thanks.

Brian
Up Topic Welding Industry / General Welding Discussion / WPS

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