Rod size, type and best way to weld suggestion

[kneedeep]

:scratchchin:

Project-

Weld 2 pieces of pipe together in the yard with Miller Thunderbolt AC/DC machine.

Details-

Pipe is slightly rusty and dirty 16" diameter 1/4 thick that was cut into with a saw. Edges are fairly clean and straight.

Pipe is part of a Water Control Structure that will be buried in a levee to control water level in a natural wetlands.

I know some of you guys know exactly how to do this the easy and best way and will be happy to advise a 'Rookie" !!
:thumbsup:



Not this pipe, but a old 16" one already on the place

 

[Shield Arc]

What I'd do is bevel both pieces of pipe to 37 1/2 degrees, grind a heavy 1/16-inch root face / land. Use a 5/64th inch drill bit to set the gap. Make 8 1-inch tacks around the pipe. Weld the first section that has the closest gap with 1/8-inch 6010 or 6011, at about 55 to 60-amps. Next weld the opposite section. Always weld the section with the closest gap first, then try to weld the opposite side. Grind each start and stop, make a little ramp on each start and stop. Once the root pass is complete, wire wheel brush the weld, and grind the starts and stops again. Turn your machine up to about 75 to 80 amps and use 1/8-inch 6010 to make the hot pass. For the fill / cap you can use 1/8-inch 7018, or 5/32-inch 6010 or 6011. For 1/8-inch 7018 try about 115-amps, for 5/32-inch 6010 try 85 to 90-amps.

 

[Arc weld]

Not really a job for a rookie as it will require a lot of out of position welding unless the pipe can be rolled. You'll also need a pretty good fit up or you'll run into big problems. If one pipe is already in place, will you be able to get enough room underneath to weld? First thing to do is get a wrap-a-round or use a 2' square or 2 2' squares to make sure the pipes are cut perfectly straight, not fairly straight. The last thing you want is a big gap(s). Then they need to have a bevel like Shield Arc suggested. For an experienced welder, the easiest and fastest is to weld it downhand from 12 o'clock (12-6 cw and 12-6 ccw) with 6010/6011 just like stick welded pipelines are done. There's a few different ways to fit the pipes but it depends on the welders experience. If you clearly don't have enough welding experience, it would be better to get someone that does. I'm not trying to discourage you but welding pipe is a lot different than welding flat on a table. 6010/6011 also throws more sparks and you will want at the very least leather sleeves. You want to stay to the side so you don't get really burn't. Pipelines are usually butted tight and the root pass is run hot to melt the bevel ends into the root pass. To do this takes experience and a perfect fit. You could also put a land on the pipe and use a 1/16" to 1/8" gap. Welding rods make good gap spacers and the gap will shrink from the heat. The idea is to get 100% penetration but your project might not be too critical in that regard. You can use downhand 6010/6011 for the entire weld but you'll probably want to use 1/8" for the root pass and then 5/32" for the fill and cap passes to speed things up. A pipeliner would use 5/32" or 3/16" and even 1/4" rods for fill and cap. That's it in a nutshell but it's hard to explain the complete process to someone with little welding experience.

 

[kneedeep]

The pipes are factory cuts and I should be able to turn with tractor after tacking.
I had a idea of how to weld it, glad to get good advice from experienced welders. I should be able to do this by following the procedure layed out.

Thank you very much

 

[Shield Arc]

Here are some pictures of how I fit pipe. Now remember this is for all up hill welding. And on small dia. pipe. So you'll want to make your tacks longer.

 

[Gary Fowler]

The only thing not mentioned is that you must grind back on the inside to remove all the pits and rust. Rust will really mess you up when trying to make a weld. Clean it up completely even if you have to remove a lot of the material.

 

[Farmerford]

Shield Arc and Arcweld:

Thanks for the good advice. I am trying to resurrect the welding I learned in vocational agriculture class and then used on the farm some 55 years ago, all with a Lincoln 180 amp tombstone AC (that my brother still uses regularly). At least I have upgraded (I guess you can call it that) to a Miller Thunderbolt!

Can you elaborate on a few points?

Shield Arc:

Why do you weld the closest gap first?

If you were welding downhill, how would the fitting in your pictures be different?

What do the last two pictures show?

Arcweld:

What makes downhill welding easier and faster than uphill?

Thank you both for sharing your experience.

 

[Shield Arc]

Farmerford as you make the root pass welds the gap will close up on you. If the gap close up too much you can always take a zip disc and slice the gap open again.

I never really messed with down hill welding. I'm not a pipe weldor. Strictly structural, in my little bitty world of welding, welding down hill will get you fired.

The last two pictures show the inside of the root weld. These pictures are not perfect, but about as good as I can do. Like I said I'm not a pipe weldor. I worked union all my life, getting caught welding pipe on a job with union pipe weldors is not real healthy! :laughing:

 

[Shield Arc]

Here is how I clean the inside of the pipe, like Gary mentioned.

 

[IslandTractor]

How do you guys measure 37.5 degrees? I understand the general idea but how does one maintain anywhere near that sort of precision in the field or even in the shop when working with a grinder on a curved surface??? Does it really matter if some of the welded area is beveled at 45 or 30 degrees?