I'm working at a power plant, welding a high pressure feed water line from an economiser. The pipe is 12" gr 106c heavy wall carbon steel. The prep on the pipe is a 37.5 degrees 1/3 of the pipe (from the root) with a feather edge 5/32" root opening. The rest of the joint is square up to the od of the pipe. I'm using a 70-s2 filler wire 1/8" dia.
My problem is I'm not use to filling root openings larger than the dia of the filler wire I'm using. The size and sch of the pipe made it mandatory to go with this size root opening as the root closes up as I work my way up the pipe. Any suggestions?
Skip
I run my heat cold enough to allow me time to feed the wire in the leading edge or backside of the puddle. If the fitup allows, start your arc, feed the wire from the opposide side one bevel or the other. Feed wire in gradually and feed a little of the other root face. When a puddle is started you can either continously feed wire as you progress forward or dip it in and out. This will depend on the amps you are running. One of the advantages to having this gap is the ability to look yourself in.
Thats how I do it. Hope it helps.
G Austin
Try to keep your wire around 90 degrees from the torch and in the center of the gap feeding toward the torch then just work the torch from side to side while feeding the wire.
Are you putting in any tacks before you weld the root? I would always put in at least 3-1" tacks at the 4, 8 and 12 o'clock postions and preferably 4-1" tacks in the 6, 3, 9, and 12 o'clock postionst. This prevented loosing my orginal root gap dimension.
Mike
Skip,
After you tack weld the pipe joint, check you root opening. Perhaps the joint may have closed up at one or two sections. That root opening may be 1/8" or just a hair over, weld that area first and the rest of the joint may close and give you the 1/8" root that you are comfortable with.
Good luck,
Jinx
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