2G Penetration

Date 03-30-2011 21:19

A welder can qualify the 3G FCAW welding test but we seem to be having trouble with the 2G modified test.
I know 3G qualifies for 2G but I like to be thorough. The welder has also qualified 2G and 3G and 4G for SMAW.

The 2G practice tests consistently have lack of penetration on the root pass (the fillet weld like first pass).
After all my testing I am coming to the conclusion that the fillet weld is the hardest weld of all.
I am a good inspector but a terrible welder. What tips could I give my welder(s)?
We are running Lincoln NR-232 on 3/8" material.

By ravi theCobra (**)

Date 03-30-2011 21:33

What does the groove prep on the 2G look like ?

By welderbrent (*****)

Date 03-30-2011 23:34

Ravi,

If I understood him right he is running the optional test for welder qualification in the horizontal position which is Fig 4.32 (p. 182) in the D1.1-2008.

That makes it a single bevel groove weld where the bottom plate is a square edge, top plate at a 45* angle with a 1/4" gap and a backing plate.

Most guys miss it either from trying to carry too much of a puddle on the first pass or because they have the wrong electrode angle.

Are they trying to single pass the root, or double pass it? I'm guessing double since you describe it as a fillet.

Have a Great Day, Brent

By Shane Feder (****)

Date 03-30-2011 23:59

MiddleTommy,
Run the first run as hot and as fast as your WPS will allow.
Al (803056) has commented frequently on this forum on the difficulties of passing fillet weld tests, irrespective of how good the welder is.
As noted above, angle is also critical.
Weld as if it is a 2F and not a 2G and ensure the arc is doing its job by welding fast enough to stay ahead of your puddle.
FCAW and GMAW (especially) are notorious for laying what looks like a beautiful bead but has no penetration underneath.
Hope that helps,
Regards,
Shane

By MiddleTommy (*)

Date 03-31-2011 15:53

Groove prep is good an clean. no space between backup bar and test plate. All A36 material
doing full root in two passes.

By jwright650 (*****)

Date 03-31-2011 11:49

Tommy,
I have tested a few guys who work for an erector and they seem to have problems using the NR-232 on the 2G mod (except 1" unlimited test) that you are talking about. I have cut the coupons to bend them and the backing bar falls off(literally!, no joke) due to a thin layer of slag between the root and the backing. I had to work with them to get them to quit pushing the puddle and use two root passes, after we they saw that this worked better, they could pass it any day of the week. They were pushing the puddle and trying to wash in a big ole single pass for the root and they could not stay ahead of the slag.

By MiddleTommy (*)

Date 03-31-2011 13:57 Edited 03-31-2011 14:02

Thanks everyone. I know 232 is hard wire to run.
Since I last posted my welder turned his machine way down. and his root pass was better.
I think his electrode angle and staying ahead of the puddle will do the trick (after some more practice)
Then we can work on increasing the speed and volts

What exactly is the proper electrode angle? We have tried several

By MiddleTommy (*)

Date 03-31-2011 15:18 Edited 03-31-2011 15:38

I finally downloaded the FCAW welding guide from Lincoln
They recommend for the root pass only on a horizontal butt weld (NR-232 .072).
1-1/4 - 1-1/2 Stick out (Bigger than normal usually 3/4 to 1-1/4)
5 to 30 drag angle (instead of 0 to 30)
17 to 18 volts (way low for normal welding usually 20 to 24 volts)
85 to 110 wire speed (in/min)

This is consistent with my welder experience of turning it down.
Only he turned it down from 22v to 20v

Funny, On a horizontal fillet they recommend you up at the 23-24 volt range