Complete failure of a TIG weld...

Yes, a brittle, crystalline fracture right under the initial 1/4" plug weld, which I had filled quickly. These were the pivot pins and the retaining plates for my front end loader.

jsw

Reply to
Jim Wilkins
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I posted a simple demo of hardness vs elastic modulus once that involved bending hard and annealed bugle head screws held by their points in a vise. The difference was very obvious between the two, but without an identical reference it's difficult to compare. In this case you could cut three pieces, harden two and anneal one of those, then bend all three. The annealed one represents what you can do to fix it after welding.

jsw

Reply to
Jim Wilkins

Good to see you here, Ken. You might be interested in this brief piece on hot-shortness. It's all a little fuzzy:

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Reply to
Ed Huntress

would you consider doing exactly the same thing an inch or so away with some of your tig compatible bronze and tell us if you get the same failure? Seems there was a thread with that in it just lately around here.

not everything is weld able. There are ways to make sparks off metals and examine what you get but sometimes just the four and a half inch grinder and a piece of known structural mild steel as a control can give you an idea if what you have isn't mild steel. The first guy also told you how heat it quench it bend it.

Fran

not cross posted

Reply to
fran...123

The fact that the weld stayed with the heavy piece suggests that the nipple was hot enough.Was the sheet on a steel bench that would take the heat from the sheet. Barring that it could be two dissimilar metals.

Reply to
F Murtz

Was the nipple cast or machined? Most pipe is made overseas with very poor quality control as to metallurgy. As long as the pipe holds pressure, it passes.

My suspicion is the pipe was bad steel.

Reply to
Ernie Leimkuhler

machined (cut threads).

Maybe, but the weld clung to pipe very well, and broke off near where it made contact with the sheet metal.

i

Reply to
Ignoramus20864

Heck, just the 40-F room temperature could have been a major contributor to the failure, especially if there was a breeze. When in doubt, preheat the workpiece before welding, and let it anneal and cool slowly after...

Iggy: Got a small blacksmiths's forge? A propane weed-burner and a stack of firebricks is all you need for a makeshift forge. Two layers for the floor and base, two walls, and a little arch over the center, aim the weed burner in one end and stick your work in the other with fireplace tongs. It will concentrate the heat nicely.

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Reply to
Bruce L. Bergman

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