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is 15/5 PH steel machinable in its hardened state?

metalmagpie

Titanium
Joined
May 22, 2006
Location
Seattle
A guy brought me a nice bar of AMS5659 which turns out to be the same as 15-5 PH stainless. A quick file test shows it to be pretty hard. I know this is heat treatable. If it's hard (as opposed to annealed) is it still machinable?

metalmagpie
 
Machines? I have a Nardini 1440E and a Kondia BP clone.

metalmagpie

OK, so basically light duty manual machines (no offense). See if you can get the "Hxxxx" number for the material you've been given, lower numbers (like H900) are actually harder, higher is softer. If on the low end you can use cobalt HSS, but if H900 you might be better off with carbide as long as you can keep the setup as rigid as possible.

If you have to tap any holes it's worth it to get some premium taps meant for hard materials. Ditto drilling, use stub cobalt split point where you can. Lower SFM as appropriate.
 
Even in its max hardness (H900) it's fine to machine with standard tooling, even drilling with HSS (drill life will be short but you'll get by). Carbide will work better for milling and turning but I've gotten by with HSS before. Biggest issue is tapping; you'll need special taps and/or increase your minor diameter (go to 50% or less thread, which generally should be fine since the material is so strong). Threadmill is strongly preferred, but you won't be doing that with manual machines.

I've had very good luck with "molecular" tapping fluid for tapping inco 718, gr. 5 titanium, and 15-5H900. Not sure what exact formula, but it worked better than moly-d and tapmagic.
 
oh, lets say light/medium! seriously, not a crapped out SB 9 and a sherline FFS. yea, what I was thinking, turning, ok, tapping, not so much, without some special precautions..
 








 
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