" Doug Goncz " wrote in message
...
I assume it's mild. But it could be fully annealed high strength, too.
It's the
integrated hanger and dropout, about 5/16 inch thick, with bosses around
dropout and hanger, that is, a thinner, yet substantial neck that is
engineered
to bend.

Well if it could be anything, that doesn't help much. :^) If it's an air
hardening steel (like 4340 I think?) it'll crack if you quench with water.
Low carbon 1020 doesn't harden per se, however it is definetly stronger
after quenching from an orange or yellow heat (did this the other day with a
coat hanger, incidental to more heat treating ... incidentally!). 1040 and
up get glass hard and must be tempered after quenching.

So I thought if I plugged the hanger threads with a crank bolt, then
torched it
a good long while, it'd be fully annealed and ready to bend again.
Probably
should have fully annealed after the accidental bend, which may have work
hardened the hanger neck.

Nah, a small bend won't really work it much. If it's mild I wouldn't worry
about it; annealed 4140 supposedly is extremely ductile as well. (30%
elongation is it?)

To anneal just about anything, you only need to heat it until nonmagnetic
then cool at a rate slower than causes hardening... although I'm sure
"slower" steels like air hardening alloys need much longer soaks.

Seems clear now. The right way to repair MUST be get everything out of the
way
after the accident, torch it, rebend it, torch it again. Yes?

Not necessarily. Your part might need the work hardening to strengthen it.

But do I harden it a LITTLE to give it some strength after annealing, that
is,
redden, quench, polish, and temper way down toward full temper but not all
the
way. Actually a full temper is stronger than a full anneal, right?

Can't do heat treating with unknown metal as I mentioned above.
I assume this "full temper" means either temper for ideal strength vs.
toughness, or fully tempered, temperature-wise (which would be up to a dark
cherry red, just about; not the more orange temp used in hardening)? In
either case, yes it would be a lot, and little stronger (respectively) than
an annealing. Remember tempering is like...controlled annealing. The full
deal (orange heat, slow cool) tempers out every last bit of stress in the
metal.

Personally, if I were going to fix your mount dealie, I'd spark it with a
grinder to get an idea of what kind of alloy it is, hot or cold forge it
back to shape then heat treat if necessary. Since I don't like unrequired
manual labor I'd let you polish it. :^)

Tim

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