GMAW Globular or Short Circuit Transfer

Date 07-22-2011 00:10

Hello everyone! I have a couple of questions I would like to get professional opinions on regarding GMAW short circuiting and globular transfer qualifications and WPS’s.
(1) A WPS using 90% Ar-10% Co2; 0.045” diameter ER70S-6 filler; 149 to 182 amps; 22 to 29 volts.
(a) Would the low end of amperage/voltage be short circuit?
(b) Would the high side of amperage/voltage be globular?
(c) Would you accept this WPS as prequalified globular to AWS D1.1?

(2) Welder Performance Qualification Record using 90% Ar-10% Co2; 0.045” diameter
ER70S-6 filler; 149 to 182 amps; 22 to 29 volts; Position 3G-up; Bend Test in lieu of RT; Listed as globular transfer.
(d) I know that globular relies on gravity but is 3G-up possible?
(e) If triggering was used what is the chance of passing a bend test over RT?
(f) Would you accept this for globular qualification or short circuiting?

Thanks in advance.

By TimGary (****)

Date 07-22-2011 00:29

1. a - With 90/10 and .045, you should get into spray transfer at 26V. 22 - 23V would be short circuiting, 24 - 25V would be globular, or there abouts.
c - neither short circuiting or globular would be pre-qualified.

2. d - 3g is not possible or practical with globular.
e - slim to none
f - see 1.-a

IMHO... Globular is useless unless your machine is stuck on those settings, un-adjustable, and your only trying to temporarily trying to stick together two pieces of sheet metal...

Tim

By bamaCWI (**)

Date 07-22-2011 00:57

Thank you for the info.

By Lawrence (*****)

Date 07-22-2011 03:43

Just use FCAW... sheesh.

(1) I think you will find that 190 amps is the lowest spray transfer amperage that is manufacturer recommended for .045 solid wire.
a. Yes
b. Yes
c. no

(2)
(d) it can be done... But it's stupidly impractical.. Even if you could get a pqr and qualify welders off of it.. Production would be inconsistant.
(e) triggering is a stupid technique for structural applications.. Bad chances.. Trigger sheet metal only.. Not D.1 code work. Can it be done? Yes. chances of succsess? very slim.
(f) I would like to see chapter and verse quoting that globular is not prequalified (it shouldn't be in my opinion, but nobody asked me)... However your WPS ranges go into short circuit range.. So NIX on WPS as prequalified as it currently stands.

By fschweighardt (***)

Date 07-22-2011 12:34

For whatever it is worth, Lawrence has it pretty well indexed.

Whenever we release a contract package, we specifically disallow globular transfer for solid wire mig. We have had a few guys try to sneak in a globular pre-qualified WPS for out of position structural work and we dont play like that. I say sneak in, technically it is allowed by the code, but we still won't let them do it.

By bamaCWI (**)

Date 07-22-2011 13:54

Thanks Lawrence. I am glad to see someone with the same interpretations and opinions.