DIYbanter - View Single Post - Anybody here machine 17-4ph HH-1150?

dan

wrote in
rec.crafts.metalworking on Mon, 2 May 2011 18:40:16 +0000 (UTC):

So I'm starting a job machining 174-ph HH-1150. I've found lotsa info
on condition H1150 but not much on HH1150. I know that the HH1150 is
heat treated twice at 1150 degrees F and that it's hardness is 28RC.
It is softer than the annealed condition. What I have not been able to
find out about is whether it will be gummy and tend to stick to the
cutting tool like 316SS or 304SS. It's been several years since I
machined any 17-4 (12 years maybe?) and I don't remember the condition
it came in. I don't think it was HH1150. It seems like HH1150 is now
more common than H1150 because it is mostly backwards compatible with
H1150. But how long this has been the case I don't know.
Thanks,
Eric

I've turned a fair bit on a swiss lathe. It is gummy, and the chips
don't like to break. It will work harden if you look at it funny.
Feed at .0015"/rev MINIMUM. Don't get it hot, keep coolant on the
cut, don't tickle it. Get into the cut and keep cutting. Lower
speed(rpm) higher feed(ipr). I don't know what SFM I run it at, but
I'm usually working with .250" to .625" stock and start off a 1500
RPM. If you find the right conditions, your drills and other tools
will last as long as if you were cutting 303ss or 304ss.

A light clean up pass(.010") will give a good finish.

--

Dan H.
northshore MA.