[mateo32]

Ok so I'm having a serious issue at work, the pipe I'm welding on is becoming magnetized and I have no idea why. What I need to know is how to remove the magnetism from the pipe so I can weld it....? Our quality control people have tried running a de-magnetizer over it to no success. We coiled the lead around the pipe and it seemed to work once but the magnetism came back later and the coil trick didn't work again. We tried reversing the polarity and using straight polarity as well. I'm welding on an alloy 5" carbon steel with 2.25 % chrome pipe, schedule 80 and it's also nickel plated. It's on jack stands in 20' lengths......???????????????????????????????????????????

[kermdawg]

Is it possible to run on AC current? Thats an old trick to negate the effects of magnetization. Also, be sure you put your ground as close as reasonably possible to the joint your welding.

[RichardH]

Ok so I'm having a serious issue at work, the pipe I'm welding on is becoming magnetized and I have no idea why. [...] It's on jack stands in 20' lengths......???????????????????????????????????????????

Environmental? What's in the area around where it's being stored, and where it's being welded? I'm wondering if it's picking up an electrical field that's magnetizing it.

If this is "bench" work, have you tried changing the orientation of the pipe 90 degrees? If it's parallel to an electrical field, this would make it cut across instead. Or is it already magnetized when you start handling it?

[Superiorwelding]

Ok so I'm having a serious issue at work, the pipe I'm welding on is becoming magnetized and I have no idea why. What I need to know is how to remove the magnetism from the pipe so I can weld it....? Our quality control people have tried running a de-magnetizer over it to no success. We coiled the lead around the pipe and it seemed to work once but the magnetism came back later and the coil trick didn't work again. We tried reversing the polarity and using straight polarity as well. I'm welding on an alloy 5" carbon steel with 2.25 % chrome pipe, schedule 80 and it's also nickel plated. It's on jack stands in 20' lengths......???????????????????????????????????????????

First the welding process can magnetize your pipe in itself. To answer more in depth we would need the type or grade of the pipe example A36, 1018 etc.
-Jonathan

[mateo32]

Is it possible to run on AC current? Thats an old trick to negate the effects of magnetization. Also, be sure you put your ground as close as reasonably possible to the joint your welding.

Well yes, It's a tig root and hot pass (er90s), then stick (9018) fill and cap. I put the ground maybe a foot or two away. I have a braided copper wire rope that I wrap around the pipe and then clamp my ground to the hanging portion of it.

[mateo32]

Ok so I'm having a serious issue at work, the pipe I'm welding on is becoming magnetized and I have no idea why. [...] It's on jack stands in 20' lengths......???????????????????????????????????????????

Environmental? What's in the area around where it's being stored, and where it's being welded? I'm wondering if it's picking up an electrical field that's magnetizing it.

If this is "bench" work, have you tried changing the orientation of the pipe 90 degrees? If it's parallel to an electrical field, this would make it cut across instead. Or is it already magnetized when you start handling it?

Well the piping is actually in crates and is released in small batches. The work is being done in a large graded dirt lot adjacent to a coal / natural gas power plant. The pipe is transported with a fork lift and faced with an electric facing tool then set up on jack stands that run a long distance. The piping seems to become magnetized after sitting on the jack stands for a few hours even if not being touched and is also becoming magnetized after welding on it.

(Can't rotate the pipe 90 as its too large and heavy and needs to run parallel to the structure it will eventually be mounted to and supported by).

[mateo32]

Ok so I'm having a serious issue at work, the pipe I'm welding on is becoming magnetized and I have no idea why. What I need to know is how to remove the magnetism from the pipe so I can weld it....? Our quality control people have tried running a de-magnetizer over it to no success. We coiled the lead around the pipe and it seemed to work once but the magnetism came back later and the coil trick didn't work again. We tried reversing the polarity and using straight polarity as well. I'm welding on an alloy 5" carbon steel with 2.25 % chrome pipe, schedule 80 and it's also nickel plated. It's on jack stands in 20' lengths......???????????????????????????????????????????

First the welding process can magnetize your pipe in itself. To answer more in depth we would need the type or grade of the pipe example A36, 1018 etc.
-Jonathan

I don't remember the code i'll try to find out tomorrow and get back to you...

[RichardH]

The work is being done in a large graded dirt lot adjacent to a coal / natural gas power plant. The pipe is transported with a fork lift and faced with an electric facing tool then set up on jack stands that run a long distance. The piping seems to become magnetized after sitting on the jack stands for a few hours even if not being touched and is also becoming magnetized after welding on it.

Power generating station, eh? Nah, probably no environmental electrical fields there.

Principals of electromagnetism, for what it's worth... A magnetic field passing through a coil (whether due to the field moving, expanding, or collapsing) will create electricity; conversely, an electric field passing through a coil will create magnetism. Same holds true for non-coiled wire (i.e., a long pipe), though the effects are lessened (as you've probably seen iron filings on the floor dancing around your welding cables).

Lacking any special welding knowledge here, I'd say it's coming either via fields in the air from the nearby plant, or (very plausibly) via current passing through the pipe from one jack stand to the next because of voltage in the soil finding a lower-resistance path. It's very possible to have voltage potential between two points of soil, with nearby lightning strikes or downed power lines being two extreme examples. A power station is another likely scenario.

May I suggest a simple test... Put an insulator between the pipe and each of the jack stands, and see if the problem goes away.

Cheers,
Richard

[mateo32]

The work is being done in a large graded dirt lot adjacent to a coal / natural gas power plant. The pipe is transported with a fork lift and faced with an electric facing tool then set up on jack stands that run a long distance. The piping seems to become magnetized after sitting on the jack stands for a few hours even if not being touched and is also becoming magnetized after welding on it.

Power generating station, eh? Nah, probably no environmental electrical fields there.

Principals of electromagnetism, for what it's worth... A magnetic field passing through a coil (whether due to the field moving, expanding, or collapsing) will create electricity; conversely, an electric field passing through a coil will create magnetism. Same holds true for non-coiled wire (i.e., a long pipe), though the effects are lessened (as you've probably seen iron filings on the floor dancing around your welding cables).

Lacking any special welding knowledge here, I'd say it's coming either via fields in the air from the nearby plant, or (very plausibly) via current passing through the pipe from one jack stand to the next because of voltage in the soil finding a lower-resistance path. It's very possible to have voltage potential between two points of soil, with nearby lightning strikes or downed power lines being two extreme examples. A power station is another likely scenario.

May I suggest a simple test... Put an insulator between the pipe and each of the jack stands, and see if the problem goes away.

Cheers,
Richard

Thanks for your input Richard, It's been a couple days of messing with this now and what we have discovered is....
If I wrap the welding lead of the stinger (Tig torch in this case) around the pipe (around 3-5 wraps) strike an arc and put my tacks in, just like I normally would, the magnetism dissipates quickly and is usually gone before I get in all four tacks. Pretty simple but without having experienced this before it took a lot of trial and error.

[kermdawg]

It makes sense in an oddball sort of way. Usually you would wrap the work lead around the work a couple of times to alleviate the magnetism...somehow the pipe has picked up the opposite charge, so wrapping the stinger lead around it does the job the work lead usually does.

Thats a good welding tip Glad you figured it out bro.