I didn't know that. Thanks for the tip!:salute:
I got my info from here; (some time ago, and I should have looked it up again before posting.
)http://www.boltdepot.com/fastener-infor ... Chart.aspx
I always figured that grade 2 (aka. garbage grade) was the low end for steel strength wise. I guess that I now know better.
Found a nice little graphic on McMaster that might be of use. It's just a quick-look chart showing different steel alloys and their yield strengths (note: things like Tool Steel may go all the way up to 140,000 psi).
As for the bolts (where you got your numbers).... One thing to remember is that nobody wants a bolt that bends (makes it hard to screw in, ya know?). In addition, the parts are physically small. Those two things combined mean that manufacturers can use heat treatment (and quenching) to make the bolts stronger than they would "normally" be.
On the other end of the spectrum, people like to bend pipe and such so hardening isn't necessarily a good thing (remember: harder also means more brittle). And so they don't heat treat/quench.
Or even for parts that don't get bent a lot (say, I-beams), welding will likely destroy any heat treatment so there's just no point in doing it.