Reading this thread I believe many are confusing stiffer with stronger.
They are not the same.
A 1/4" glass rod is stiffer than a 1/4" steel rod, but the steel rod is stronger.
A solid bar is far stronger then a hollow tube of the same diameter, but the tube will come back straighter if it's bent unless it's bent far enough to kink.
A bar takes more force to bend, but doesn't return to straight as well, ............. alloys being equal between the two.
Welded pipe is often made from 1018 steel and so is hot-rolled as a rule.
If anyone want to test this to be sure, (and not have to believe when they see on the internet my post included), just go get a 1" diameter water pipe (called 3/4" in the plumbing industry) and a 1" hot rolled steel rod. Get them both 4 feet long.
Now clamp them 1 foot from the end in a vice on a heavy duty bench or put them into a buried pipe in the ground 1 foot deep and pull. See which one you can bend easier.
The pipe will flex with just a little effort and come back to straight (or mostly straight.) When you go past the point it can resist, it will kink and break over.
The bar will not bend easily at all, but when (or if) you do get it to bent, it will stay bent about 50-60% of whatever bend you put in it.
Try it yourself and see.
None of this is related directly to the OP question, but may explain the debate so it's easier to understand.
Some are saying "stiff" when they mean "strong", and vise-versa
Last edited by szihn; 03/17/18.
