Magnitized Drill Stem

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Can someone explain the science behind why this happens?  Is it strong enough to stick a nail to it (to test it), or will it only rear it's ugly head when welding on it?It's not what you can buy, it's what you can build.
Reply:Drill pipe goes round and round as it drills into the formations seeking black gold. I don't know how "scientific" it is, but It was explained to me that the process of rotation causes it to magnetize. Usually a nail won't stick to it, but shavings will. The problem with welding magnetized pipe is when the pieces you're welding together are opposite polarities. They are opposing magnetic poles. Wrapping your lead around one of the pipes several times while striking your arc and welding usually makes a difference. If it doesn't work the first time, wrap it several times in the oposite direction. You are effectively changing polarity in the pipe your lead is wrapped around and the more times it's wrapped the more significant the change. I usually wrapped it 8 or 10 times, but as few as 5 has worked too, depends on the amount of magnetism involved probably. Hope this helps, there are many with more "science" than I have here, but this method always produced some benefit for me. Once the weld adheres to both pieces of pipe and a bead begins to form the polarity problem is solve and you can unwrap you lead.Only when the last tree has died and the last river has been poisoned and the last fish has been caught will we realize we cannot eat money.                                         -Cree Indian ProverbSA 200 LincolnVictor Torches
Reply:Thanks.  That tells a lot.  I had forgotten about wrapping the lead.  I had heard that in the past, but forgot about it.It's not what you can buy, it's what you can build.
Reply:What Gizzardgutz told you is right. The only thing I'll add is pipe doesn't have to be rotated to become magnetic. Oilwell tubing and sucker rods will become just as magnetic as drill pipe just from being run and out of the hole.
Reply:What you're seeing when drill pipe becomes magnetized is the earth's magnetic field affecting the steel in the drill pipe.  You can reproduce this by taking a paper clip, straightening it, and pulling it across a small magnet about 10 times.  The paperclip will become slightly magnetic.  Same thing is happening to the drill pipe as you raise and lower it in the well hole.  The earth's magnetic field is much weaker, and so it takes more repetitions to cause the magnetism to appear.Wrapping your leads around the pipe is creating an electromagnet.  Take a look at any highschool physics book, and you should find this experiment.  Iron resting inside a coiled conductor becomes magnetized by the electricity flowing through the conductor.  Moving iron through a coiled conductor induces current to flow in the coil.  The more wraps of cable you use, the stronger the effect.  This is why they use very fine wire in electric motors and solenoids.  You can create more loops with smaller wire.  I think that current is more important than voltage, if I remember the formulas correctly.  This is why welding lead works better than your 110 volt extension cord.The direction you wrap the leads serves to either cancel the existing magnetic field in the drill pipe, or reinforce the field.  This is why reversing the direction you wrap the cables around the pipe fixes the problem.The magnetism in the pipe is only negated while electricity is flowing through the welding leads, so you cannot check this before you start welding.  If you check the pipe for magnetism before you start welding, you'll still find it.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:I know that welding with AC will help when experiencing arc blow, would this have any effect on material that is already magnetized?Have we all gone mad?
Reply:The material under discussion IS already magnetized. Welding two pieces of pipe together, with opposite polarties at the weld. If you're experiencing arc blow in the process of, say, a fillet weld, try changing the direction of the weld. Instead of left to right, try right to left. If this doesn't work for you, look at the problem being the rod itself. LH absorbs moisture as does Jet rod. Try drying them in the oven or buying new rod and keeping them dry. Humidity makes a big difference in the above mentioned rod.Only when the last tree has died and the last river has been poisoned and the last fish has been caught will we realize we cannot eat money.                                         -Cree Indian ProverbSA 200 LincolnVictor Torches
Reply:Originally Posted by gizzardgutzThe material under discussion IS already magnetized. .
Reply:Maybe someone here is more qualified to answer this than me. I misunderstood what you were asking the first time. I can't for the life of me see what difference it would make?Only when the last tree has died and the last river has been poisoned and the last fish has been caught will we realize we cannot eat money.                                         -Cree Indian ProverbSA 200 LincolnVictor Torches
Reply:The use of true AC (alternating current) could very possibly have a degaussing effect while the arc is maintained, yes. Or it could be that true AC is only affected half as much by any magnetic fields too. Since we cannot really see these magnetic domains that occur within steels and that are caused by induced magnitization it would be really really difficult to prove anything shy a lot of expensive test gear and testing procedures. When you look at all the cute little graphics associated with explanations you get to see all the little arows indicating a supposed north and south polarization. When you look at a piece of magnitized steel you won't see any of those little arrows.  Not being able to see the little arrows (  ) there isn't any way of really knowing what to do for sure. In short it's a blind mans dart throw.
Reply:Originally Posted by sn0border88I know, what im asking is would welding with AC be of any benefit in this situation as opposed to DC.  Im assuming not, but im looking for confirmation.
Reply:Yes, AC current will definitely help with the situation. The few times I have worked with drill stem, and encountered the problem I switched to AC and it helped dramatically.I'm a Lover, Fighter, Wild horse Rider, and a pretty good welding man......