replying to Ed Huntress , Sandarpan Mukherjee wrote:
huntres23 wrote:

On Sat, 15 Nov 2014 18:18:01 +0000, Sandarpan Mukherjee
It's not easy to find specific elongation properties of 4140 when it's
heat-treated to 216 kpsi tensile. At the extreme end, 285,000 psi,
elongation is 11% and machineability is 65%. Hardness is 578 Brinell
or Rc 55.
That's more machineable than I expected, although it's carbide-only at
285 kpsi, and I didn't even know that it could develop 285 kpsi
tensile strength. That kind of tensile strength, in diameters larger
than wire, usually is associated with fairly brittle specialty steels
and very low elongation.
So, at 216,000, elongation can be expected to be over 11%. That's not
terrible. It shouldn't be inclined to break as soon as the yield
strength is exceeded.
The thing is, heat-treating sounds tricky -- normalize, reheat for
time, oil-qnench and extended temper -- and it probably requires real
expertise to achieve those extreme properties without brittleness. You
can buy it normalized but the time/temperature sounds like a job for
carefully controlled furnaces.

http://www.matweb.com/search/datashe...a46a1f1 eb1c3
Good luck!
--
Ed Huntress



Thanks Ed,

At this point I'm not overly concerned with heat treatment procedures.
Heat treatment in general is a tricky thing. I am just trying to zero in
on the actual material.

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