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  #1  
Old 01-05-2008, 09:50 AM
sglide sglide is offline
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Default tip for welding extremely magnetized pipe

and welder working in the oil field will face the dreaded mag pipe sooner or later, and they will all stugle and fight it, sware and throw there stinger and wish they werenot a welder for a bit
and ive herd lots of ways of dealing with mag pipe (and not one of them has worked for me)

first, how do you know its magnatized?
well if you strik an arc and your arc fan jumps every where but where you want it and the weld sounds like you are welding under water its magnatized

second is whats happening to my weld?
well with a but joint you now have two magnets and your trying to put them together where there poles are, and your trying to do it with liquid metal

now the trick
you have to conect the two magnets to gether to make them one, this will shift the pole points to the end (of cousre)
ang hers how i do it and how i figured it out

i had one so bad once that i had to gas weld the first pass to get it to weld (after one pass all the way around itll weld normally, well almost normaly)
and that got me to thinking about molten metal
the next time i had to do a really bad one i tryed some faster fill techniques
i knocked the flux off some 7018 and fed it into the puddle along with the 6010 i was welding with and low and behold it would fill
i made a pass all the way around with ease in about a tenth of the time as gas welding! and my next pass welded normaly

now of course this will not pass x-ray
and on all mag pipe you have to cap with LOHI
but i thought i would share this trick that has work so well for me
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  #2  
Old 01-05-2008, 10:01 AM
sglide sglide is offline
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sorry for the spelling, i have a monster of a hangover and my spellchek is screwing up
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  #3  
Old 01-05-2008, 03:05 PM
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sglide, thanks for sharing the tip. I havn't run into any magnetized pipe yet. I havn't been welding long enough, but expect I will one day. I weld mostly plant piping and it doesn't get magnetized like production tubing does from the sucker rod rubbing up and down on it or from the friction of rotating drill pipe.

I may be welding stock corrals out of used oilfield tubing one day though. So do you have to make any adjustment to your amperage or make any special manipulation when using your tig'ing filler technique?

I have never used a double ground lead to try and counter magnetism. Do I take it that it doesn't work as good as they say?

I didn't know there was much oil production in Michigan. From the photos in your one thread, it looked like you were working on a new production site.

Well now, I hope your head hurts real bad. 'Cuz some of us have to work today!
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Old 01-05-2008, 03:57 PM
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I have used the a little dab will do ya with the second rod for years but not because of your problem but for large gaps and thin metal. thanks for the tip.
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Old 01-05-2008, 04:32 PM
AmickRacing AmickRacing is offline
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Never had to weld on anything that was magnetized but I have a question you guys can probably answer...

the leads turn into electro magnets (to some degree). Could you wrap your welding lead around the pipe a few times (somewhat close to the weld, but not close enough to burn it up). Would that help counter it, or just make things worse?
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Old 01-05-2008, 09:05 PM
sglide sglide is offline
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Quote:
Originally Posted by houlibar View Post
sglide, thanks for sharing the tip. I havn't run into any magnetized pipe yet. I havn't been welding long enough, but expect I will one day. I weld mostly plant piping and it doesn't get magnetized like production tubing does from the sucker rod rubbing up and down on it or from the friction of rotating drill pipe.

I may be welding stock corrals out of used oilfield tubing one day though. So do you have to make any adjustment to your amperage or make any special manipulation when using your tig'ing filler technique?

I have never used a double ground lead to try and counter magnetism. Do I take it that it doesn't work as good as they say?

I didn't know there was much oil production in Michigan. From the photos in your one thread, it looked like you were working on a new production site.

Well now, I hope your head hurts real bad. 'Cuz some of us have to work today!
Quote:
Originally Posted by AmickRacing View Post
Never had to weld on anything that was magnetized but I have a question you guys can probably answer...

the leads turn into electro magnets (to some degree). Could you wrap your welding lead around the pipe a few times (somewhat close to the weld, but not close enough to burn it up). Would that help counter it, or just make things worse?
i have tryed the wraping your leads around the pipe a bunch of times and its not worth the efort it takes to spool your leads back in when your done
in order to counter the magnatism with your leads you would need to know the polarity and magnetic force of the pipe your working on and then know how many wraps at what heat it would take to nullify it

an ya, we got oil
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  #7  
Old 01-05-2008, 11:04 PM
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OZWELDER OZWELDER is offline
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Guys
Magnetic effect or Arc blow as its known down here,is often rectified by moving the earth return lead and winding it around and around the pipe to form a field opposite to the polarity already present.

If on the first attempt it is markedly worse you have gone the wrong way. The thing to do is remove the earth lead and re wind it back the OTHER way, the opposite hand to the first attempt..
A polarity change at the welder terminals can work if the process variables can tolerate the change.

On occasion not even this is enough we have resorted to obtaining an AC welder and using that.
This was at Gladstone, Queensland Australia on the site of Queensland Alumina Limited then worlds largest Alumina refinery. 1300 kms of pipework.
Hope this helps

Ozwelder
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  #8  
Old 01-06-2008, 09:56 AM
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What is the purpose of mag pipe?
Is it magnetized accidentally or on purpose?
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  #9  
Old 01-06-2008, 12:24 PM
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just accidentally
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  #10  
Old 01-06-2008, 12:48 PM
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Stored too close to welders and their related magnetic fields for too long.
It got dropped.
The shipping tie downs were loose; allowing pipe to bang around during the journey.
Manufacturing SNAFU.
There are more reasons to be sure....
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