I will try to be very thorough laying this all out. I am a welding student. I am learning a very specific process for a job at a local shipyard. I am using the following: 6" schedule 80 carbon steel pipe, 6g position, 6010 root pass, 777 0.045 cv wire(flux core) filler and cap, 75%/25% Ar/CO2 sheilding gas, Lincoln Invertec 350.
My root pass is good. No IP. No blobs. Exterior is good. No blobs. The slag gets filed then brushed then ground out before I begin the FCAW passes. Now here is where I start cussing. I start my bead @ 6 o'clock and invariably I have piping porosity within the first inch-inch and a half. I have gone back and forth with grinding it out before continuing, and it never shows through in the cap passes. My instructors have presented all the possible causes they can think of and I have made sure to eliminate each of these variables from the equation. At this point my only guess is that the heat in the puddle is driving slag and/or gas upwards and as the puddle freezes over, it creates the porosity. Anyone out there got any light they can shed on this. I would greatly appreciate it.
Edit to say: I will post pictures tomorrow.
Hello brother,
I used to weld fire sprinkler pipe down in Florida. I don't know if this will do the trick but it IS worth a shot. Try going to a 90/10 ArCO2 mix. On your flowmeter/regulator adjust your rate to about 22-25cfh. I do know even with some of the structural I've done that too much cfh through the nozzle will make you have porosity. Hope this will work out for you.
Cody
I used to weld fire sprinkler pipe down in Florida. I don't know if this will do the trick but it IS worth a shot. Try going to a 90/10 ArCO2 mix. On your flowmeter/regulator adjust your rate to about 22-25cfh. I do know even with some of the structural I've done that too much cfh through the nozzle will make you have porosity. Hope this will work out for you.
Cody
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Thank you, Cody.
I will try this in class today, and update tonight.
I will try this in class today, and update tonight.
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Well, I didn't get to try it today. I got moved onto 7018 filler and cap on schedule 40 for a different/better job that just opened up. Thank you for the feedback anyway, Cody, Much appreciated. If I get to try that weld again I will bump this thread with an update.
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2 things come to mind...turn voltage down just a little...like half a volt. and increase stickout .
I have seen it before also... and I am with you on it driving you nuts too because aside from the piping porosity, everything seems to be going really well.
good luck with your stick test.
Jody
I have seen it before also... and I am with you on it driving you nuts too because aside from the piping porosity, everything seems to be going really well.
good luck with your stick test.
Jody