Issue TIG welding Laser cut parts (worm holes)

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Guys, trying to help out a buddy weld some laser cut parts. I was under the impression that laser cut parts were clean enough to go as-is. When welding, there are holes popping out as you can see. We tried hitting it with the grinder to clean and it seemed to help a bit, but its really time consuming and not preffered. Is there something that we are missing?Machine is a Miller Synrcowave 180 that was lended to us. It only has amp control on the front panel. There is no flow regulator, using straight argon. Torch is air cooled, no gas lense. Regular filler for ER70s-2. All material is mild steel, laser cutting grade (clean).Any opinions?
Reply:I'd hit all to be welded surfaces with a flapper wheel and get to shiny metal. That's clean enough for stick or dual shield but tig has to be clean, clean, clean.
Reply:I have never welded laser cut steel so don't know if that is a problem with cleaning or not. If grinding all of the joint clean helps then it is a problem with contaminated steel. If it doesn't help then you need to start looking for leaks in the hoses and check the torch for leaks also (backcap/cup gasket). You can also try turning the argon flow up to see if that will help. Be sure to hold a tight arc with a short stickout from the cup for best argon coverage.Airco Ac/Dc 300 HeliwelderMillerMatic 200 (stolen)Miller Maxstar 150STLMiller AEAD200LE (welding and generating power) Hobart MIG
Reply:That looks like outgasing blowing out from the tubes. From my phone the tubes look grey as well. Is there mill scale left on them? Cant see to good bud.I hate being bi-polar it's awsomeMy Heroes Have Always Been Cowboys
Reply:Seems like some sort of contamination, looking at the sloped part of the steel it doesn't seems like the metal was ground clean. Try using a flap wheel. If there is no flow regulator how do you know how much argon your using for Shielding? Could be way to much flow or not enough
Reply:OK so took the part to my house with my welder and it welds up fine. This other part has the exact same prep, so this confirms that its not the material. I have a gas lens and I also have a regulator (cant recall where its set (10-15 cfm iirc)). Since we cannot swap torches between our machines were gonna look at getting a gas lens, new tank of argon, regulator and hoses.Hope this helps someone else!
Reply:False alarm, we were actually able to turn the flow rate down. (I thought it was a pressure regulator). It was set up at 24 cfh, turned it down to 13 cfh and no more holes, all is good. So the cause was too much argon flow.Hopes this maybe helps someone else.
Reply:Figured it was a Shielding gas flow issue. Glad you got it figured out
Reply:Hello maccos, all of the other folks have hit on the "cleanliness" of the materials before you weld on them. With the GTAW process this is a must. The statement: "Cleanliness is next to Godliness" definitely applies when you are using the GTAW process. Even though laser cutting is a very precise and generally clean method of cutting it is still a thermal cutting process and as such will produce oxides on the cut surface and adjacent heat affected zone. Mill scale from metal production is an oxide and as such requires removal in most circumstances. Occasionally, if you are welding on some "cold rolled" products, you can get away without grinding/polishing but you will need to degrease the parts because they have lubricants/chemicals left on them from the production process. The S numbers associated with GTAW filler metals will help in some cases with missed contaminant removal due to varying levels of Silicon. Theoretically the higher the S number the better the cleaning of that grade with regard to the metal being welded. You said, in the end, that you determined that too high of a flow rate was associated with your "worm holes". Excessive gas flow can cause turbulence/a venturi effect to occur and draw atmosphere into the weld area and cause contamination of the type that you experienced. Thus, too little gas flow can result in "holes/weld discontinuities" and too much gas flow can similarly contribute. Gas lense combinations will definitely provide better and more complete coverage with regard to coverage gases and when possible I will run them regardless of material type or application. That being said, you can certainly make quality welds without a gas lens too. Much of that choice is simply a matter of personal preference or what you're used to.   Those are nice looking parts and the end result will surely look great. Good luck and best regards, Allan Attached Imagesaevald
Reply:Whatcha building anyways!I hate being bi-polar it's awsomeMy Heroes Have Always Been Cowboys