HEY GUYS, INTRODUCED MYSELF IN THE TECH SECTION SO I WILL SPARE IT HERE.
I AM WELDING 3/8" PLATE, 1-G 60°, 3/32" ROOTFACE, 1/8" ROOT GAP, WITH E71T-1, VOLTAGE 25 IPM 200-215, 75-25 SHELID.
I'M HAVING PROBLEMS WITH "WORM HOLES" IN MY WELDS. FORGET THE TECH. NAME BUT THEY ARE GROOVES IN THE TOP OF THE WELD RUNNING A cm OR TWO. I'VE TRIED HOT, COLD, NO WEAVE, SLIGHT WEAVE, GUN ANGLE, AND I STILL GET THEM UNPREDICTABLY. ANY INPUT IS APRECIATED.
MATT
Are these holes or tracks. Do they extend below the visible surface?
I have experienced some 71T1 wires that have "worm tracks" in the surface of the weld that do not extend into the weld. I read an article somewhere that the slag system on the T1 wire freezes faster and sometimes causes this based on what conditions are used during welding.
Check the basics first. All gas connections are tight. Gas cup is clean. Wire is free of rust/excess shop dust. Gas flow is sufficient and no drafts are taking the gas away. Base metal is cleaned of any lubricants rust etc.
The procedure you describe seems fine. Check with http://weldreality.com/ for some great information of the GMAW/FCAW process.
Have a nice day and I hope you get your answers !
Gerald Austin
http://www.weldinginspectionsvcs.com
Wormholes result from welding over any type of impurity at the root of your bead that makes a bubble as it vaporizes. This bubble naturally floats to the top of the bead while the puddle is still molten. An elongated track on top of the bead is from the bubble floating along the top of the bead, underneath the slag. This is a comon problem with Innershield (FCAW) as the spot of impurity causing the bubble is usually a small piece of slag left over from a previous pass. It is important to remember that wormholes are not just a surface discontinuity. They are a defect as the track left from the bubble extends all the way down to the root. Subsequently, if you do not remove the entire wormhole and the little pocket where it originated from, it will most likely reoccur through your next pass.
FCAW is a great process, but deceiving. It is so easy to make a good looking bead with that many welders become complacent and don't pay close attention to slag removal or watching the puddle closely. FCAW has a bad tendency to trap slag underneath the bead, at the root face, but still leave a beautiful looking surface. This happens most often during groove welding when the welder tries to weave in the groove or does not hold a steady straight line. What happens is that when your electrode wire touches the side of the bevel, rather than the very bottom of the joint, the puddle will bridge over slag trapped at the very bottom of the joint. This is most prevelant when the groove is deep and narrow, which doesn't allow for even the slightest side to side movement. To make matters worse, when the pudlle starts bridging over slag, it has a natural tendency to carry the slag on in the same manner resulting in a long slag line at the root face of the weld.
The best ways to avoid this are to have as wide a groove as practical, be carefull not to tie into the side of the bevel and watch the leading edge of your puddle closely. The leading edge should be sharp and convex. If you notice that the leading edge is bunching up or becoming slightly concave, that is because it is allowing slag to flow underneath.
Anyway, wormholes are a good indicator that you have a trapped slag problem. When you see a wormhole, I recommend that you grind it completely out and watch for an indication running parellel with the bead. If you find one, you know you have a slg line that needs to be removed. Keep in wind that before you re-weld the groove created from grinding out the defect, it is best to widen out the top of the groove so that you don't wind up making the same mistake again.
Keep practicing and watch that puddle!
Tim
When all else fails, try cutting your voltage slightly. Chall.
Matt:
Try Chall's advice first if your using Lincoln wire. This wire has the potential for what is known in the field as "chicken tracks". Typically this occurs from excessive voltage, or extreme work/travel angles.
These do not extend into the weld as noted by Pipewelder. They are quite common where high productivity is required by the welder (the Man wants you to put out.)
These welds have been UT and RT tested without failure (at least from the tracks), but look like someone tried to run a dull drill all over the weld face. These usually run in all directions, and the ironworkers here like to see who will have these present in their welds, and who will not. Some guys just know this wire and can run it using just about any welding parameters or equipment.
This indication was quite common during the bridge-seismic-retrofit period on the column casings, but it was deemed irrelevant by the powers that be. Some of the proponents inexperienced field inspectors wanted to reject these welds until further info was established.
Try to set your machine up using the minimal required voltage to run your bead. You'll be surprised how low you can turn this down and still hold an arc.
in my shop somebody bought the wrong kind of welding gun...a MIG gun. not much of a problem, except that the contact tip is too close to the edge of the gas cup. Innershield and Outershield run best w/ a 3/4" stickout, but in order to get that stickout you have to hold the gun pretty far away from the metal, which makes the gas shielding ineffective. we had to screw the gas cups out till they had 1 thread holding onto it in order to get the right stickout AND to get some good shielding action. just something else to consider...
If you are using Lincoln wire, try sheilding with Co2 gas. I have had this same problem in the past and Co2 fixed it. The Hyundai wire runs good with 75-25.
HEY THANKS FOR THE ADVISE GUYS, I GOT A NEW SPOOL TODAY AND IT RAN PERFECTLY. THE ONEI WAS USING WAS PROBOLY 10 YEARS OLD. MY INSTRUCTOR IS CHEAP. ANYWAY, WHAT GUN ANGLE WOULD YOU GUYS ADVISE FOR SAID GROOVE?
When I read your last reply, 10 yr old Flux core. I had to laugh, Junk it, It should have been stored in an oven just like rod. It too has a flux, and it can absorb moisture. It's a low hydrogen rod turned inside out. Tell your instructor that, see what he says. As for gun angle, no more then 15° off of 90°.
Forum
