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Up Topic Welding Industry / Welding Fundamentals / Root Reinforcement Issues
- - By supermoto (***) Date 04-03-2009 11:12
So I am in class yesterday and I am having problems getting full penetration on 60 degree V-groove open root 1/4 steel with GTAW.  I am using a 3/32 root opening and a 3/32 filler.  I cannot do this in either 2G or 4G.  1 G and 3G are no problem, I think that they are easier to do because I have gravity on my side.  I have tried everything such as running 80 to 120 amps different stickout, different angles, keyholes, everything.  I can get a little bit of penetration on the 2G but I have to run it at 120 and don't let the filler leave the groove.  But if I do this it doesn't look like it gets good side wall fusion and I feel that I am cooking the weld by going to slow at that amperage.  Can somebody give me some ideas it is driving me nuts.

Thanks.
Parent - - By Kix (****) Date 04-03-2009 12:32
Loose the root face and go to a knife edge root face prep.  Turn you amps down (around 80amps) and go to an 1/8" gap and 1/8" rod to learn.  Hold the rod in the gap and just melt the rod.  Don't key hole it.  Are you trying to walk the cup while doing this or are you free handing it right now?
Parent - - By supermoto (***) Date 04-03-2009 13:11
I have a knife edge.  I tried the lower amps but just didn't want to push through.  When I tried no keyhole and it didn't even get flush. 

In theory I think that it will work but I tried that except with 3/32.  Very frustrating because I feel I have tried everything.  I will try eveyones suggestions.  Can't be that hard.
Parent - - By Kix (****) Date 04-03-2009 14:10
No, try the lower amps with the bigger gap and rod.  Go to the 1/8" root opening and 1/8" rod.  These are the easiest starting parameters.  Knowing how to do the 3/32- 3/32 is for the pro's when there gap shuts on them or they get a fit where they have to work with what they got.  For just starting out, use this set-up.
Parent - By Shane Feder (****) Date 04-03-2009 14:28
Supermoto,
Every welder welds slightly differently so just take the advice you have been given and try it out. It is quite possible you will end up doing something completely different but if you use the advice given it is a starting point.
I have never done GTAW on plate but I have welded thousands of GTAW root runs on pipe and the problems you are experiencing on 4G plate are the same as the bottom of a pipe, shovel the wire as fast as you possibly can. Gravity is working against you instead of for you as you mentioned.
2G is not quite the same but if you are not getting enough pen but you are picking up the edges, don't change your amps / volts / travel speed, just try feeding your wire a bit quicker.
Hope that helps,
Cheers,
Shane
Parent - - By pipewelder_1999 (****) Date 04-03-2009 14:26
Try practicing the ovhd and horizontal with the ability to peek at the back side. This is easiest on the horiz as you can get your head lined up with the end of the joint and move left to right to see what is happening . If you see the metal fusing but instantly sucking back, try using a larger filler metal diameter or lower amperage. Change only one variable at a time.

Spend time on the sides and not in the middle . Though very little side to side is needed, pausing on the sides and fast across the middle may help. 60 Degrees may be a bit tight for the way you are welding. Maybe open t he groove slightly which will reduce the amount of heat needed to get things flowing.
Parent - - By supermoto (***) Date 04-03-2009 16:43
I will try a 1/8 root with 1/8 filler and if that doesn't help I will try to do a little side to side weave.

I guess I was just trying to treat it as if it were a root with E6010 and just trying to let the arc push it through.
Parent - - By mightymoe (**) Date 04-03-2009 21:12
What flow rate is your argon set at? Are you keep the tungsten pointed strait into the weld?  Are you walking the cup or free handing it?
Are you feeding the wire or just walking over it?
Parent - - By supermoto (***) Date 04-04-2009 14:28
I turned up the flow to 25 due to it being a heavier gas and gravity would pull it out of the overhead position.

I am freehanding it, I would walk the cup but the cup sort of arcs/sticks to the bevel face.

I have been keeping the tungsten straight into and tried putting some push angle just to try different techniques.

I guess I have tried both feeding and walking over it, depending on what you consider feeding and walking over it.
Parent - By mightymoe (**) Date 04-05-2009 19:45
Keep working at it. One day it will just click.
in your first post you tired 120 amps but still did not beak down the bevel.
Try going slower. establish your weld pool, then start moving all the time watching the weld pool. Keep the weld pool slightly larger than your root opening. 80 to 90 amps on 1/4" plate sounds good. Don't worry about "cooking" carbon steel, try to cook it.
When I was in tech school I was told to brekdown the wire and just touch the sides of the bevel, which is good advice. I learned to slow down and be more patient, watching the puddle consume the edge of the bevels, on my first welding job after school. I learned it from watching some pros.
Have your instructor run a root and watch closely.
If the other positons are not a problem than it's just a matter of time and practice before you ace them all.
Parent - - By scrappywelds (***) Date 04-04-2009 14:33
If you are trying to push it in, watch the puddle carefully. What I mean is look at the "ghost" dancing around if it isn't and it just going side to side you are not penatrating completely.If you don't know what the "ghost" is it is the little glass ball thet forms when GTAW welding in the molten weld puddle. I would follow the 1/8" gap suggestion with 1/8" wire. I myself like 5/32" gap and 1/8" wire "walking" over the wire.
Parent - - By scrappywelds (***) Date 04-04-2009 14:37
walking over the wire is melting the wire without moving it in your hand. feeding is moving the wire in your hands to keep up with the consumtion rate.
Parent - By mightymoe (**) Date 04-05-2009 19:55
some times just keeping a little forward pressure on the wire helps with penetration. keep the wire 15 to 30 degrees off the plate and  push it into the weld pool.
Up Topic Welding Industry / Welding Fundamentals / Root Reinforcement Issues

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