Remember that one of the main goals for the hot pass is to not mess up the root.
Even though welders call the pass after the root pass a "hot pass" amperage is not Always hotter than the root...but often times it is.
For a tig hot pass, about 10-20% more amperage is often used for the hot pass...but sometimes the hot pass is done with the same amperage as the root pass.
IF you go too slow or too hot or both, you can melt thru and sometimes that results in something called "suck back".
Suck Back is when you melt all the way thru the root and usually the metal Sucks back to below flush.
And that will usually fail you on a 6g test.
Here are a few tips that can help prevent suck back:
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WELD PROCESS = TIG, GTAW, GAS TUNGSTEN ARC WELDING,
METAL TYPE = carbon steel PIPE
THICKNESS = 6 inch schedule 80 pipe wall thickness .430"
WELD TYPE = groove
JOINT TYPE = BUTT WELD OPEN ROOT WITH 1/8” GAP AND ZERO LAND
LAYWIRE TECHNIQUE USING FORWARD AND BACK MOTION
AMPERAGE = 130 AMPS
TUNGSTEN = 2% LANTHANATED, 3/32"
FILLER WIRE = 1/8” ER70S2
POLARITY = DCEN
GAS FLOW = 20 CFH argon
CUP SIZE = 8
PRE FLOW = MANUAL
POST FLOW = 10
ADDITIONAL SETTINGS =
TIPS: EXTEND ELECTRODE ENOUGH TO GET A DECENT ANGLE SO THAT WALKING THE CUP OR FREEHAND WELDING BOTH WORK WELL
Aim for an arc length that is equal or less than the diameter of your tungsten electrode.
Torch angle can be forgiving provided your arc length is tight.Keep the hot tip of the filler wire shielded by the argon envelope from the tig cup
Snip oxidized tip of filler metal before a restart