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Pipe welding

Posted: Thu Nov 29, 2012 11:57 am
by Joe the welder
I go to a technical school for welding an I'm havering trouble with smaw on 5g pipe. When I weld from the 6 o'clock to the 9 o'clock position my penatration on my root pass comes out flat instead of a crown. Dose anyone have any advise for me on how I can at least get it to crown?

The spacifices are 6 inch diameter pipe 3/8 thick. My root opening is a 1/8 inch an my land is a 1/8 inch. An the welding machine is a Lincoln invertec v350-pro. An the electrode is 1/8 fleetwood 5p+ (6010)

Re: Pipe welding

Posted: Thu Nov 29, 2012 6:53 pm
by Otto Nobedder
1/8" 5P is the right rod for the job.

I do this weld quite hot, compared to most people. I like 105A, and once the puddle is established on the tack, and the rod is hot (doesn't take long... ;) ), I jamb the rod into the root opening like I'm trying to force it through, and drag the rod (it's still 90 degrees to the pipe... "pull" might be a better word.)

The arc is almost entirely inside the pipe. It sounds like a hive of pissed-off bees. I can raise my hood. There's very little light or arc spray outside the pipe.

It works because the flux insulates the rod from the edges of the land at the bottom of the bevel.

This works at 95A, too, but I like 105 because I can go to 1/8" 7018 without adjusting the machine.

Here's one done that way on 8" sch 80, in 5G (root wire-wheeled for the camera):

Image

Steve S

Re: Pipe welding

Posted: Thu Nov 29, 2012 6:57 pm
by Joe the welder
Is your land an root opening still a 1/8 inch to?

Re: Pipe welding

Posted: Thu Nov 29, 2012 8:55 pm
by Otto Nobedder
Yes. 1/8" root opening (it closes slightly as it draws), and the land on that weld was closer to 3/32".

Steve S

Re: Pipe welding

Posted: Fri Nov 30, 2012 12:26 am
by Joe the welder
Ok thank you ill give a shot