So in terms what causes welds to fail more often? This is hypothetical, but if a trailer is made, would cases of under cut on those welds or cold welds be more likely to cause a failure. If im not explaining my question well please let me know.Sent from my XT1080 using Tapatalk
Reply:That's like asking, "Which is worse, Death or Taxes?"More seriously, probably cold welds lead to more sudden, catastrophic failures. Undercut can happen wiht a properly fused, otherwise sound weld. What undercut does is reduce the base metal thickness right at the toe line of a weld. This creates a notch, a stress concentrator. While this notch can lead to sudden, catastrophic failure; it's much more likely that the notch enables fatigue to occur. Fatigue cracks are slow, progressive damage, until they grow so large that the stress applied causes them to fail.Of the two problems, I'll take undercut as I'm more likely to see the crack that grows from it before something really bad happens. A cold weld with lack of fusion, particularly a single pass fillet weld, can let go if you look at it or use harsh language where it can hear you. I think this a much greater threat.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
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ab nailed it.I hate being bi-polar it's awsomeMy Heroes Have Always Been Cowboys
Reply:Thanx sir. I am a tend to undercut kind o noobie. Buy im learning by watching people and seeing all the lil things i can do to prevent it. I never realized welding in certain positions could cuase more or even accentuate undercut. Sent from my XT1080 using Tapatalk
Reply:Fixed a lot of both over the years. Usually if they came in with two parts that needed to be put back together it was from cold weld, if something was dragging behind it was undercut. My brother bought a new piece of farm equipment and when he folded the wing down it fell off because the weld that held the tube to the hinge plate never penetrated the plate except for about a 1" spot. That was one of the few times I took pics and sent them to the company and they actually paid me for the repair. The only time I got paid to do warranty work on someone else's machine. I found several other welds that were bad on that piece too.
Reply:Here are two good articles from ESAB on the subject. http://www.esabna.com/EUWeb/MIG_handbook/592mig10_3.htmhttp://www.esabna.com/EUWeb/MIG_handbook/592mig10_5.htmAnd another one on destructive testing. A quick and dirty way to see how much penetration your welds are getting. Some members here believe a fillet weld break tests shows nothing, I guess they know more than ESAB about welding.http://www.esabna.com/us/en/educatio...g-of-Welds.cfmDont pay any attention to meIm just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:ive already put a factory exhaust on my truck then drove in 8 miles to work, about a mile into my drive home i heard a loud rattleing coming from my exhaust . i pulled over and saw that the factory weld on the hanger was cold and popped right off the pipe. there was no penetration i could have hit the weld area of the pipe with sand paper and you would have never knew there was a weld there.
Reply:Isn't it true that undercut can be fixed with another bead whereas cold welds have to be ground off and rewelded?GravelThe difference between theory and practice is that in theory there is no difference.
Reply:I was just going to ask if its ok to put another weld over it or will that cause things like increase Haz, ductility loss or any other problems?Sent from my XT1080 using Tapatalk
Reply:I don't see where there would be anymore chance of increasing the haz, than a 3, 6, 12, etc pass fillet weld.Dont pay any attention to meIm just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:So a yes to a second pass to pretty things up lol?Sent from my XT1080 using Tapatalk
Reply:I would on an undercut weld, but first I'd run a grinder down through it. Dont pay any attention to meIm just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:Thanx for all th learning opportunitiesSent from my XT1080 using Tapatalk
Reply:At least with under cut you know you its not a cold weld.Easier to fix than a cold weld too.Last edited by mad welder 4; 02-07-2014 at 02:33 PM.
Reply:That just scratches the surface. http://www.lincolnelectric.com/en-us...at-detail.aspxDont pay any attention to meIm just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:Oh im sure.. But everyday i pick up something from u awesome weldersSent from my XT1080 using Tapatalk
Reply:Originally Posted by PrestonFabInceveryday i pick up something from u awesome welders
