Welding Tips and Tricks

Me and several guys in my shop have been practicing a 2g (horizontal) groove test. When we remove the backing plate and grind down to flush a very small but visable line on both sides of the weld are visable when we bend the coupon these lines will sometimes come apart and somtimes they stay the same when they come apart the metal appears to be crystalized (if there is such a thing). Weare welding with a miller 252 we have tryed .035 and .045 with the same results. we started with the settings suggested on the chart on the welder and have varied up and down from there. .035 calls for 21.5 325 When i try this same test without the backing plate the coupons look good and bend perfect. these lines appear to be where the 3/8 plate meetes the backing plate. This happens when we do a root bend. (please help)

wowie it really asks for 21.5 volts and 325 IPM?? thats wild, i'm not saying it doesn't but that seems very hot and very fast for 3/8, are you filling these grooves in a single pass? if so that would make a little bit of sense but i digress... if your root is splitting it basically means lack of fusion, in other words you didnt provide adequate heat to take the 4 pieces of metal ( each half of the test piece, the backing strip, and your wire) and combine them in the puddle. the crystalized thing though sounds to me like porosity, this would look something like lava rock or some guys say sugar this is typically seen when your arc wasnt properly shielded by the gas, and contaminents like atmosphere are included in the puddle then when the puddle cools the air pockets are sealed inside. you may not be flowing enough gas for the application it may be a technique issue with mig there are alot of factors that can add up to a poor weld give us some more details if you can like how many passes what kind of weave you run, if any, how much gas youre running etc. and i'm sure me or one of the other guys here can hook you up

Thanks for the reply. I have been filling this groove with 3 passes( actually over filling) thats another problem. 1 pass is not enough and 3 is over doing it. I was off on my wire speed .035 calls for 21.5 425 .045 calls for 21.5 325 using 75/25 mix on gas. My gas pressure is 32 cfh. i have been weaving my bead just enough to catch both sides of the 1/4 in groove.
W hen the coupon comes apart its not always right down the bead it tears in a jagged pattern mayby across the groove. Could i be over welding(too hot). Can you explain why this works so well without a backing strip. I have been welding with a stick for 25 years with wire for 2 years so i am open to any suggestions I know I have a lot to learn probably about stick and wire. I say the day i stop learning is the day I die. (please help)

to be honest, gas flow sounds about right. but in my opinion, i weld that style joint with about 18 or 19v and 200-215 ipm wire speed, i also am a pusher for the most part there have been countless debates on push vs. pull, but i push, i've passed a boatload of tests so it works for me as you are making your weave across the root, be sure to pause and take your time pausing at the edges and really give that puddle time to develop alot of guys when they start honing their wire skills find out that they simply run too hot, and too fast. if you are welding too hot that can cause a whole new load of problems, it may be that you are burning into the backing strip way too much so when you shave it off, you lose the meat of the root pass. When you weld with an open root however, you are forced to pay more attention to your travel speed and that may be the factor that makes your settings work for open root i would say that if you are over filling, that should be a good indicator that too much fill is going into the puddle and be sure that when it comes time to cap your weld youre really taking advantage of that 1/8" into the base metal alot of guys will put that second and/or third pass in a little hotter so they dig deeper into previous passes and that helps them keep their re-enforcment (crown) from piling up too much. Just a couple things you may try and some background on that particular test its good to share info here but it would be alot easier to watch you burn and then try to fix the issues make sure to reply back and tell us about your progress best of luck!

How thick is the backing bar (1/4") and what is your joint preperation? Single bevel or V bevel? What size gap. I ask this because you may be better off running two roots if your spacing between the test plates is wide enough. also, don't rapid cool your test at any point, that could possibly cause it to harden. not likely, but maybe.

thanks again for the replys my groove is a 22.5 bevel on each side with a 1/4 gap . im going to try turning down to 19v 215 like Rod Burna said and try two root passes. my backer is 1/4 or somtimes 3/8 Iwill let you guys know how this goes

Good luck. Hope it works out for ya.

Hey guys its been awhile been real busy just wanted to say thanks for all the advice I took your advice Rodburna I turned dow to 19v 225ipm ran two root passes worked great I took my 3g up and 4g overhead test today passed them both to get cert in all positions plate. Feels good to accomplished a task especially when it throws some challenges at you.This proves ther are no dumb questions just dummies that wont ask questions. Not sure what i would have done with yalls advice. Thanks again Brent