Qwertypolk wrote:Some backup on this would be good, but cold rolled is generally stronger only before the working. Hotrolled has been annealed. When worked, hotrolled should work harden, and become just as strong as cold.
Depending on your supplier, cold rolled usualy has a bit more work hardening to it, in mild steels this ammounts to almost nothing. Hot rolled tends to be a "hair" softer. Having done hardness tests on sheared sheet steel for a company I worked for I can tell ya jus tthe act of cutting (with shear of some kind) imparts a far greater work hardening within 1/8 of the edge than the difference between them. (That was a boring week)
The variance between suppliers/mills can also vary between batches considerably as well. If you are buying virgin stock, you can pobably see the variance in the spec sheets... when I went to look on McMastercarr it even said "Warning hardness rating is estimate and sample may not be the same" Unless you are buying to a spec (which you pay premium for) there is not a significant difference.
About the only functional difference is when deep dishing or deep forming a bowl or severe anticlastic curve without annealing, I tend (not scientifically proven) find cracking can come faster with cold rolled, but I've never done hardness tests on my own stuff, let alone actualy mic it to see what other variables there are.
-Takeda