Welding Tips and Tricks

im taking a 6g test on 2.5 inch sch 80 carbon steel. tig the root with a 3/32 gap this works great. then i do a hot pass to almost fill the bevel. my problem is my cover pass(atom arc 3/32 7018 at 75 amps) is under cut on the higher side of the weld. i have been weaving the cover pass, but would two stringers be better? or is it something simple like angle of the dangle?

Jamiewells.

My guess is that you should be able to weave that cap without undercut. If you weave it, or put in stringers, in both cases you will need to ensure that you fill both sides of the joint as you move along. Ensuring correct fill on the sides of the joint is usually a question of pausing and allowing the weld metal to fill up the edges, before moving to the other side of the joint. While pausing, a slight aiming of the rod towards the bevel is helpful to ensure good fill.

In 6G, in order to maintain your rod angle orientation towards the pipe, you will have to change your posture and change your arm positions. On the bottom of the pipe, from 5 to 7 o'clock, you are essentially welding overhead. But the challenge is in the transition positions, for example, from 7 to 8 o'clock, and 5 to 4 o'clock. The smaller the diameter of pipe, the quicker your posture/arm positions will be changing. 40" diameter pipe 'is like' welding plate, compared to 2.5" diameter pipe. Sometimes, if the welder has not developed a good posture during the transitions, the rod orientation is compromised, and the puddle flow become erratic.

In what position around the pipe are you having difficulty with undercut?

Tanks.
Alexa

Fill it 1/16 under flush, run first stringer fast and barely nick the bevel, overlap next two stringers 2/3, last stringer is fast and skinny just a beauty ring overlap half. Makes a nice convex cap for me. Run my amperage in the high 80's too. Hope it helps. Good luck

Weaved mine in,Stringers are easier.For the weave I bang into the Bevel always watching that weld puddle fill above the bevel,then I shoot across moving up about 1/16 in a z pattern ,My Exp has been not hanging out long enough will always leave undercut,I agree with the 80"ish Amp Range.Stringers Good pace even Burn,lap the stringers out,Make sure you watch the fill Hate to get busted out for underfill,or bust out for being to high because you looked at it and new you needed to run 1 more pass I believe My cover was 3 pass"s. Good LUck Man hope this helps, a lotta rod on that test,after all that i hope we where talking about 6" sch 80.

Ha, yep 2 stringers watch the fill.