[Ant428]

So I am practicing some out of position TIG, and I welded this bracket for practice. It is all 1/4" steel. I did one pass at 175 amps with 3/32 filler. The weld looked nice but needed another pass. Instead, I decided to bend it. When I did, it broke and looked like the picture below. I don't understand what happened?! Its like a white chalky break. It took a lot of force and started to bend first, but then it broke apart. Maybe I didn't clean the mill scale on the back side of the bracket? So I bent the bracket or angle iron back and it broke.

20180311_195841.jpg (31.51 KiB) Viewed 1577 times

[Oscar]

That's what broken weld steel usually looks like. Like a broken casting. Clean your metal just a smidge better. The flap disk marks don't look so pronounced in the picture, so I could be wrong.

[Poland308]

Is that galvanized?

[tweake]

really need to see the other side of that top piece.
to me the question is did the weld metal break or the base metal ?
if it tore out the base metal its ok.

[Ant428]

really need to see the other side of that top piece.
to me the question is did the weld metal break or the base metal ?
if it tore out the base metal its ok.

The weld metal split in half.

[Ant428]

Is that galvanized?

No regular steel

[tweake]

if the weld is smaller than the base meal then it will be the weaker and break in half. with a 2nd pass it would have been a different story.
but judging only by what i can see in the pic, it kinda looks like what you get when you long arc it, fusion on the sides but not in the corner of the joint. really need to break the halves right off and get a better look.
i've had similar with mig which broke looking a bit like that.

[Ant428]

if the weld is smaller than the base meal then it will be the weaker and break in half. with a 2nd pass it would have been a different story.
but judging only by what i can see in the pic, it kinda looks like what you get when you long arc it, fusion on the sides but not in the corner of the joint. really need to break the halves right off and get a better look.
i've had similar with mig which broke looking a bit like that.

But shouldn't it just bend? If I took a piece of metal and bent it, it won't break. I will do another tonight and clean everything to a shine first. I'll make sure to hold a tight arc too.
It did not break from one side or the other, it broke in the middle of the weld. So when I ripped it off, there was weld on both pieces.

[Poland308]

https://library.ctr.utexas.edu/digitize ... 1501-1.pdf

Kinda dry reading but about pg 35 there is some info about the failures during bend tests. It’s a pretty in-depth paper about bend tests of structural fillet welds.

[Oscar]

But shouldn't it just bend? If I took a piece of metal and bent it, it won't break..

No. Steel that you purchase that comes formed was formed in a different way than the weld metal that you added. Ever look up a youtube video on how steel is made? *hint hint*

[Ant428]

But shouldn't it just bend? If I took a piece of metal and bent it, it won't break..

No. Steel that you purchase that comes formed was formed in a different way than the weld metal that you added. Ever look up a youtube video on how steel is made? *hint hint*

Will do. I just didn't like that grainy look when it broke .
I am going to do a few more destructive tests

[tungstendipper]

But shouldn't it just bend? If I took a piece of metal and bent it, it won't break..

I just didn't like that grainy look when it broke .

Did you quench in water to cool it off?

[tweake]

if the weld is smaller than the base meal then it will be the weaker and break in half. with a 2nd pass it would have been a different story.
but judging only by what i can see in the pic, it kinda looks like what you get when you long arc it, fusion on the sides but not in the corner of the joint. really need to break the halves right off and get a better look.
i've had similar with mig which broke looking a bit like that.

But shouldn't it just bend? If I took a piece of metal and bent it, it won't break. I will do another tonight and clean everything to a shine first. I'll make sure to hold a tight arc too.
It did not break from one side or the other, it broke in the middle of the weld. So when I ripped it off, there was weld on both pieces.

keep in mind, as you said it needed a 2nd pass, its a small weld. the metal is thicker so the weld going to break before the steel bends.

[weldin mike 27]

A single sided fillet will always break through the weld. Unless it's a full penetration (the bracket prepped until the weld goes through the full thickness) Think about taking a piece of metal and grinding a line across it. Then bend it so that cut opens. Its a area of smaller surface so that's where it will break. If you took that same weld (that you showed) and made it a little bigger and welded both sides, It will not break anywhere near as easily.

[weldin mike 27]

On a side note, Welding a single sided fillet is the way we do it at trade school. It enables you to do a weld and then break it under an hydraulic press to examine the root with out any deformation of the plates. This means you can re-position your plates to keep welding more joins using the same material without too much fuss.

[R32Guy]

The filler rod and material being welded can create a more brittle weld joint than the base material itself.