Question About Testing Welds

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Hi All! I'm new to welding and I'm trying to get a better grasp on how to test my welds.  I'm trying to weld  1/4" angle to 1/8" tubing with my 110v mig welder and I want to make sure the connection is strong. I first tried to just do a single bead, vertical up, but the weld broke when I ripped the pieces apart. Then I tried a root(?) pass followed by a weave bead, vertical up. The tubing wall ripped when I pulled the pieces apart (see pictures). The second weld took a lot more prying with the 3' cheater bar. Where I'm confused is what should I be looking for? Should I not be able to tear any of the metal apart around the weld? Also, should I let the metal cool before I rip it apart or is it just as strong as when it is cool?Thanks for your help! This is one of the best forums I've ever lurked  Attached Images
Reply:If the failure is in the base metal, then the weld is stronger than the base metal, but is the base metal thickness correct for the application?If the base metal was correct for the application, with an appropriate safety factor, and the weld test fails in the base metal, or the whole assembly bends over on itself, you are good to go.If the base metal is way oversized for the application, the weld test may fail in the weld, and you won't really know if its strong enough unless you have some way of measuring the force required to fracture (tensile test machine).Asuming the filler metal strength is about equal to the base metal (70 ksi uts), then the cross section thickness through the weld should be about equal to the base metal thickness.
Reply:yeah what he said mate your weld was ok could be a bit pretier but one good run with 1mm wire would give you same result its down to the wall thickness of your box section mate.no need for a weave and route run in my opinion on that thickness,
Reply:You running solid wire or flux-core on that galvanized steel?
Reply:is that galv just thought it-d been cleaned up with a wire brush
Reply:That's not galvanized, it's just plain steel.  Look at the surface rust and scratches.If the weld is as strong as the thinner base material, then you are good to go.  As said, make the size of the weld equal to the thickness of the thinner metal.  If you make the weld bigger than that, you are just wasting weld (and time).Next, how and what fails could also be based on the design and the load.Let it cool before testing it.Your single bead looks like it was a little small for the force you put on it.  The root+weave looks like it was a little more weld material than was needed and the 1/8 inch wall tube was too thin for the load.How did you rip it apart?  You stuck the leg of the angle in a vise and then put your cheater pipe into the rectangular tube and twisted, didn't you?  That's a pretty tough test, on a small weld bead (not much weld metal to resist the load).  Weld your pieces together again, runnning a single bead just a little bigger than your single-bead picture, but run a bead on -both- edges of the angle onto the tube.  Try torquing -that-!Want to test your weld and welding?  Do a simpler test and weld.  Take two pieces of 1/8 inch thick steel bar/strap and overlap them, like this ................===========================================X  Weld a lap weld on -one- edge, where the X is.  Let cool, then stick one end in your vise and bend the other end over (use your cheater or just a BFH).  If it bends over and the weld doesn't break, you did OK.Last edited by MoonRise; 08-07-2007 at 04:00 PM.
Reply:This beads looks like a nice size, but I think we see that penetration was lax.The footprint is insufficient.This 2 pass weld is a bit overkill in size, but it gets the job done.Notice the full penetration, the weld held and the base metal tore.I say you can do this in one pass, just take your time with a single pass, so that the weld puddle has time to dig in. The thinner material will always rip first when there are different thicknesses involved. Nice pics.City of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:Yep, it's just plain ol' steel  I'm running .035 71t-gs fluxcore. I definitely need to work on my bead appearance when welding vertical-up. I did like you said, MoonRise: I put the angle in a vise, stuck a 3' bar in the tube and pried up using the weld like a hinge until it broke. I've done some fillet welds and butt welds with 1/8" plate and used a BFH to beat it apart and the base metal always failed except the edged of the plate - that’s how I got the settings that I used on the above piece. Do you have any suggestions (besides buying a tig  ) on how to get good penetration on the edges of plate without burning through? I wish I had some pics of the plates...Thanks for the comments!Wally
Reply:Originally Posted by tanglediver...I say you can do this in one pass, just take your time with a single pass, so that the weld puddle has time to dig in.
Reply:Hmm.  Looked like galv.  That and the white residue was characteristic of a zinc plume.
Reply:I does look a lot like galv when I only hit it with a wire cup. I probably should start cleaning up the weld area with a flap disk...That's what I get for being lazy
Reply:Take all the galv off, your welds will improve drastically.   I was thinking more heat, but can't say till you weld on plain steel.  Your UP looks great, keep at it.  you got it!DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:btw, galv steel collects rust.  Especially when it sits on a piece of mild steel.  And i've never seen that white plume except on galvanized...
Reply:Thanks guys!I'm pretty sure it's not galv - it's all new steel from a supply yard. I think the flash on my camera along with the low light conditions are giving it a silvery look (at least I hope  ). The white plume is from the flux lightly dusting the part-it's more tan in person. Here's a pic with the flux still on the root bead: Attached Images
Reply:OK, so MO heat.    The one with two passes held better because you added a lot more heat with the weave.   Try a pause at the sides.  DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Mo heat then! I'll stick the metal together, tonight and post some more pics. Would it help to pause more on the 1/4" or will that screw up the bead?