Validating GMAW Transfer Mode as Indicated on WPS

Date 08-24-2018 14:15

I work almost exclusively with the GTAW process and ASME codes. I have been asked to review a vendors D1.1 qualification documents for a below the hook lifting device they built for us. They gave us a pre-qualified GMAW spray transfer WPS. I would like to learn enough about the subject of GMAW transfer modes to be able to confidently say by looking at the weld parameters whether or not they would actually achieve a spray transfer. I have not been satisfied with what I have found online.

Is there a book out there that would clear this up for me? Preferably something published by AWS that I could cite should a disagreement ever arise.

By welderbrent (*****)

Date 08-24-2018 16:09

Good Day,

So, GMAW spray will have a high voltage input that will give you a flat smooth weld vs the rippled appearance of short arc transfer.

To start with the WPS, it should have a gas shielding of at least 80/20 and I personally prefer the 90/10. Could go as high as 98/2 with O2 instead of CO2 but that is not always a good idea for several reasons.

Without knowing wire specs, diameter, and base material some things will be hard to get definitive on.

Spray will show some silicon islands on the surface unless they cleaned it with a wire wheel and/or painted.

Can you get more info for us? Much easier with all you can get.

He Is In Control, Have a Great Day, Brent

By Lawrence (*****)

Date 08-24-2018 17:35

Spry transfer defined:

1) Open Arc Meaning that the electrode wire does not touch the work after the arc is struck.

2) Droplets are smaller than the electrode wire diameter

You can dig through the information at Weldreality.com or you can buy this excellent book

https://www.amazon.com/Metal-Flux-Cored-Welding-Parameters/dp/0975362100

Brent's data on welding gasses is good. Minimum 80% argon 90/10 Ar/Co2 is very common and workable for most carbon steel GMAW spray transfer operations.

By 803056

Date 08-24-2018 20:46

Go to the ESAB website and go to their product page. Search the electrode classification listed by the WPS. ESAB lists the ranges for the welding parameter for each diameter for spray and for short circuit transfer. You can then make a call on whether the parameters listed by the WPS are within the realm of reasonable or not.

The voltage is rather dependent on the shielding gas. I would expect spray transfer to list a voltage above 24 v unless they are using very small electrode diameter.

Al

By brownl21 (*)

Date 08-27-2018 16:32

I had found the welding parameters for the wire, but don't see any transfer mode designation associated with them.

By brownl21 (*)

Date 08-27-2018 14:00

Thanks for the responses. I'm going to check that book out. E70C-6M H4 .045" diameter 90% argon/10% CO2 is the wire/gas combo on the WPS.

330 wire speed and 28.2 Volts 15 - 18 in/min travel speed

Cover Pass 260 - 280 wire speed 27- 28 Volts15 - 18 in/min travel speed

By 803056

Date 08-27-2018 17:11

OK, you're using cored electrode. Who is the manufacturer? Look on their website to see what they recommend.

Al

By kcd616

Date 08-27-2018 19:30

sounds good to me
but like Al said check the producer
sincerely,
Kent