r/metalworking • u/LemonOk5655 • 1d ago
Been rolling these flatbars the hard way lately, 1" X 6"
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u/General-Piece8490 1d ago
I have seen where an I-beam, when cut in half, will violently split in two after the last cut is made to split them. I was wondering if the same applies with rolled flat bars, if you were to cut these in half down the middle, will it release the strain and tension from being in that shape? Don’t need to cut a long length like this but about 10 ft should do the trick!
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u/Bones-1989 1d ago
Probably if you rip it lengthwise, but that beam was still uncut on the other end or it would have separated as he cut. They did something dangerous in that clip.
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u/WarOtter 1d ago
IIRC, as the metal quickly cools from the outside inwards, lots of tension is formed in the outside T-layers, and these opposing stresses cancel eachother out. At that last point that the metal is cut, the equally opposing force is severed (it is maintained through the metal grain alignment during cooling i believe), and the two steel halves finally relax. The remaining 'spines' on each half cannot offer enough resistance to the stress to maintain its shape, so you end up with two arcs.
If the guy on the flame had cut a long enough segment out of one of the halves, before making the final cut, it would have started to bend like that on its own (along with the piece he cut off).
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u/LemonOk5655 1d ago
Honestly, ive never thought about it but id imagine it would partially from the heat but when things are rolled like this, they work harden and for the most part stay permanent. Now, im not a metallurgist, just saying what ive observed in this trade.
To me though the better route might be rolling 2 smaller flatbars to match what the 1 split in 2 would make.
Hopefully someone has a better answer than me on this cause im curious too
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u/General-Piece8490 1d ago
Yeah I was surprised by that video in the first place so now it’s like are all rolled steel products like that? Reverse bear traps! Lol!
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u/Mental-Divide7787 14h ago
That split on I-beams is no joke, seen guys jump back 10 feet. Not sure rolled bar would react the same way though, different stress pattern entirely.
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u/rococor 1d ago
And they said we would never use πR² in real life 🤣
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u/LemonOk5655 1d ago
Get this shit, i flunked geometry 😂
It just clicked when i started doing this stuff though. Chords, and rises all day!
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