|
|
Looking for advice... I have (40) pcs of 3" schedule 160 (HHX) pipe. Magnetized to the point that you can hang a tig wire from it.... my welder buddies are jacked...Anybody have a technique that will neutralize the magnetism in the entire pipe prior to fit and weld? Wrapping leads and trying an MT yoke arent workingAny advice would be greatly appreciated....Lsoult-CWI
Reply:Try wrapping your ground lead around the pipe 4 or 5 times. May have to switch directions. Or heat the weld area cherry red. Or if you are allowed run your root pass with 6011 on AC.Dont pay any attention to meIm just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:Use an AC welder and 6011 is a good bet. Also you might try tacking it in several places with a torch. That will help neutralize the magnetizem across the two pieces before you start your weld. The problem isn't the magnetizm but the difference in polarity with how you have the two pieces aligned. If you can rotate the pipes by 90 degrees, it may help.
Reply:I know your frustrated and probably experienced, but just my 2 cents, whenever I start dealing with arc blow I put my rod straight in the stinger and hold the rod like a pool stick in between your oposite index and middle finger so you can twist and turn that rod where ever it wants to go no matter how bad it thumbnails on you.I hate being bi-polar it's awsomeMy Heroes Have Always Been Cowboys
Reply:Thanks,The customer requires TIG..... I didn't mention that this is in a coil and the mag is building as more pieces are added. We're up to >100 Gauss.I need to de-mag the entire pipe before fitting/ welding.... Gauss of <10... any ideas?
Reply:Mechanical shock and heat both remove magnetism. Try preheating the area to be welded to a bright cherry red then allow it to cool prior to welding.
Reply:Originally Posted by 76GMC1500Mechanical shock and heat both remove magnetism. Try preheating the area to be welded to a bright cherry red then allow it to cool prior to welding.
Reply:Originally Posted by SuperArcDoesnt preheating to bright cherry red risk changing the metal structure and hardness qualities??? Your customer might not like that...
Reply:Originally Posted by SuperArcDoesnt preheating to bright cherry red risk changing the metal structure and hardness qualities??? Your customer might not like that...
Reply:It's true. Heating steel to 1450*F will neutralize all magnetism in steel. But the ASME B31.3 limits heating of pipe to 1150*F , and the WPS has a max interpass temp is 450*F for the HAZ. Good thinking though.lsoult
Reply:Originally Posted by sn0border88 Your best bet is to hire a company that specializes in de-mag work, there has been a few other threads on this topic recently and some companies have been recommended, you might want to start your search there.
Reply:I am wondering if you could not try demagnetizing by putting many wraps around area then shorting directly to your ground away from the pipe to prevent arc strikes. Wrap in the other direction and try again at lower amps or simply change polarity. Maybe do it is several stages down in amperage alternating polarity/winding direction? Demagnetizing is simply AC current slowly diminishing to zero.
Reply:Originally Posted by lotechmanI am wondering if you could not try demagnetizing by putting many wraps around area then shorting directly to your ground away from the pipe to prevent arc strikes. Wrap in the other direction and try again at lower amps or simply change polarity. Maybe do it is several stages down in amperage alternating polarity/winding direction? Demagnetizing is simply AC current slowly diminishing to zero.
Reply:I didn't mention that this is in a coil and the mag is building as more pieces are added
Reply:my customer had a 100-0--100
Reply:Originally Posted by lsoultI just got a quote for $5200 USD out of Jersey... The VP of our pipe distribution div would rather have a guy try to rub the mag out with a piece of carpet than pay that amount |
|
发表于 2021-8-31 23:54:59