Pipe Welding

[JOHN1]

Got to weld some 4" steel pipe and must be able to hold little water pressure.

Will E7018 do the trick.

Never have used it, but I have always had "porous" welds.

Thanks

[walker]

7018 should work fine. Make sure it is dry rod. You can bake it or keep it in a special dryer, or just buy small packages and open them when ready to use. I have never had trouble with porosity with 7018, so I suspect it was old rod.

[Paul Seaman]

7018 would be my choice, if multi pass is required then you could cover in 7018, mig or tig whatever your fancy. If you don't have a writen procedure you must follow then pick your best process and let it happen. The root pass is the hardest to get right so practice is requirement. When I did pipe in school I built a positioner so I could roll the pipe and work in the same place, the positioner was a smaller diameter piece of pipe welded parallel to the floor.

Peace,

[HAWK]

JOHN1,

If there is no procedure and "little pressure" is something you are comfortable with assuming responsibility for, then use the procedure and consumable you are most experienced at and comfortable with. Are you better with MIG than other processes? If so, can you MIG the pipe?

It may be necessary to have some help on this one. I don't know your circumstances.

[JOHN1]

"Poriousity" (think that is right) is the main concern.

Can I get as "leak free" with Mig as I can with say an E7018

Thanks Again

[tackit]

If I was doing it I would bevel the ends of the pipe to 30 degrees??? and put a land on the the ends of both pipe a little smaller than the width of a nickel. Use a welding hood's plastic clear lens to set the gap distance, place four good tacks around the joint and then taper grind them and any stops and starts so the root pass will blend together nicely..


Get the temp so you can push a 1/8 6010 rod down (touching both pipe)into the gap and drag the 1/8 6010 at a speed that just fills the gap without burning away the sides of the pipe, when the heat is right the bead should look flat and just wide enough to cover the open gap without needing to whip the rod. Then power brush the root pass and weld out with 3/32 7018. being careful not to burn through the root pass. Rule of thumb, the cover pass should be dime high and a nickel wide.

[JOHN1]

Tackit:
Thanks
This gives me a basic understanding and will work from here.

What amps do you suggest for both rods you suggested?

Thanks
John

[fun4now]

amps ??

he will need more info to get you a starting point for your amps.
how thick is the wall of the pipe ??
practice pice will give you the best amp's anser.
i would play with a few practice pices of this pipe before you start the job.

[fun4now]

responsibility

HAWK makes a good point.
if it disent hold will it leak out and ruin a priceless painting,trash the drywall, or just add some extra water to the front lawn.

[JOHN1]

I think it is schedule 40 Pipe, walls are 1/8 or 3/16
John

[boilerman79]

Pipe welding is a different animal than welding two pieces of plate together.If possible take a couple pieces of scrap to practice on and to get your heat right.make first pass with 6010.for thin wall use 3/32 rod start at 50 amps.go up or down as needed.finish with 7018 out of the can[fresh].i welded many a practice coupon before i took my test.[sch.80 8 inch.]LUCKILY i passed on the first test,but only after a lot of practice.[try 7018 3/32 rod at 80 to 85 amps.]good luck.

[boilerman79]

also,i have never welded pipe downhill,i know there is a procedure for it[gas lines and oil pipe],we run all up hill welds.6010 will run very well down hill,but it requires a little more heat than going up hill.so make sure you have your heat dialed in on a practice piece before you start you weld.

[JOHN1]

Thanks for the info:

John

[cnslmva]

BOILERMAN79,
You ought to try downhill pipe, I love it compared to uphill! Try 5P+ or 6P+ (Lincoln's Pipeliner series is killer) 1/8" on sched 40 or 80 at 130 amps for root. Get your keyhole formed and let it rip. Its alot quicker than uphill!

[tackit]

Welding downhand outside in windy conditions with fast freeze rods can leave pinholes in the weld.