Welder Qualification

Date 08-29-2013 18:36

Muttyv,

WELCOME TO THE AWS WELDING FORUM!!

Well, I don't have a hard copy or digital of D1.3 here with me. Off hand, in answer to your direct question, it is a change in mode of transfer, the process is still GMAW either way.

Now, without a book, my suggestion is to look at all your essential variables. There should be some text as well as at least one applicable Table. You will be interested in one that gives the changes in variables for the welder that would require additional testing. Make sure you look at voltages/amperage and/or wire feed speed, gas shielding mixtures, modes of transfer, etc. All these are variables with the change you are talking about, it is all a matter of which ones may cause requirements for new qualification.

Now, you know you will need to use different gas for that. Short arc will have been either 100% CO2 or 75/25 Ar/CO2. Spray is at least 80/20 Ar/CO2, preferably (for me anyway) 90/10 Ar/CO2.

Have a Great Day, Brent

By Lawrence (*****)

Date 08-29-2013 20:54

4.7 Essencial variables for Performance Qualification (all) does not speak to transfer mode.

For procedure qualification see Table 4.2 (22) A change in the mode of metal transfer across the arc. (requires requalification of WPS)

I actually ran some succsessful D1.3 PQR's this week :)

On primer and galvanized :(

By Lawrence (*****)

Date 08-29-2013 21:07

Brent,

You said:
"Now, you know you will need to use different gas for that. Short arc will have been either 100% CO2 or 75/25 Ar/CO2. Spray is at least 80/20 Ar/CO2, preferably (for me anyway) 90/10 Ar/CO2. "

Why would you say that? He may be using a spray gas already :)
Short circuit GMAW can easily be run with spray gasses.

Hook up some 90/10 Ar/C02and run 200 ipm and 17 volts with .035 filler and It will short circuit just fine.

In fact 98/2 Ar/Ox is commonly used for very thin steel because it will short circuit at about 13 volts, making it useful for welding on edges or with small diameter fillers.

In fact, there are some GMAWP operations that are advertized pulse spray with active gas ratios above 20%

By welderbrent (*****)

Date 08-29-2013 21:18

You are right about the gases there Lawrence. But how many people do? But, there are some. I used to on a couple of machines that I switched often from short to spray.

Where does D1.3 stand on Pulsed Spray? Is it a Pre-Approved process? Or does it always require a PQR?

Have a Great Day, Brent

By Lawrence (*****)

Date 08-30-2013 05:28

D1.3 is just like D1.1 regarding GMAWP

:::::::::crickets

By muttyv Date 08-30-2013 12:48

D1.3 and D1.1 do address them similarily, virtually nil. :confused:

We run 90/10 gas, for everything, including the D1.3 Qual which is on G90 material. :grin:

The reason I am inquiring is that we qualify our guys to D1.3, D1.1, ASME Sec IX, TACOM 12479550, and some others.

1) If a guy qualifies on the sheet steel using GMAW-S, but hasn't run it for 6+ months, but has welded GMAW in the spray and Pulse Modes on plate, is he still qualified for sheet?

2) Some of our WPS's are qualified to D1.3 using Pulse. Is he in fact qualified to weld pulse on sheet even though short arc was used for the performance qualification?

I have been told that we may be outside of the Code, but I have also been told we are good...????

By Lawrence (*****)

Date 09-02-2013 13:26

Forget what you have been told!

The D1.3 code clearly does not differentiate between transfer modes when it comes to welder performance qualification. It just doesn't. Inspectors can rant all they like; open the code book to the essential variables and ask them to justify their mandates.

Spray is spray, whether or not it is pulsed. As long as the welding arc has CV arc behavior, and transfers droplets across an open arc that are smaller than the wire diameter, it's spray transfer. The code may change some day, but I really doubt it.

By 803056

Date 09-04-2013 17:49

I struggled with the fact that the sheet metal code does not consider the transfer modes of GMAW to be an essential when qualifying welders. The key to the quandary is "sheet metal."

Industry's concern about short circuiting transfer is the low heat input associated with the process and the potential for fusion type defects. The issue of incomplete fusion is more problematic as the base metal thickness approaches and exceeds 3/16 inch. The fact that the sheet metal has a limited thickness range simply translates into a lower probability for fusion type defects resulting from limited heat input.

In fact, one would be hard pressed to use spray mode transfer with the thicknesses usually encountered when welding sheet metal. That being the case, the code dos not differentiate between the transfer modes because it is, for all practical purposes, a non-issue when welding thin gauge materials.

Best regards - Al