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17-4 PH vs annealed

chad883

Cast Iron
Joined
Jan 12, 2012
Location
indiana, usa
I am running 3/8" 17-4 annealed ground stock in our Citizen. Part is 4" long and .2494 diameters on both end with .294 diameter about .400 wide in middle. getting parts that ore bowed .003. Will PH material run straighter? if so what spec?

Thanks
 
Yes, hardening 17-4 can relieve some stress.

The condition you choose is up to the customer. Available conditions range from H900 (hardest, HRC 40-45) up to H1150 (HRC 28-30). The number indicates the temperature in Fahrenheit at which it's hardened.

H900 material can be re-baked into H1150 material, but not the other way around. If you overshoot, it's irreversible. Solution annealing a machined part will distort it quite heavily.
 
These parts are for our own product, so I can use about any grade. The parts need to be as straight as possible, so I will use whatever will give me that.

Thanks
 
These parts are for our own product, so I can use about any grade. The parts need to be as straight as possible, so I will use whatever will give me that.

Thanks

H900 is like one of the nicest to machine materials of all time. Slower than annealed, but comes out of the machine looking like jewelry (assuming you do your part).
 
H900 is definitely nicer to machine, but we had trouble finding hardened full length bars (that weren't way more expensive). Now the swiss parts are run from annealed bar then heat treated, and the mill parts are cut, HT, then machined. Our tolerances are open enough that any warp doesn't sink us.
 
I am running 3/8" 17-4 annealed ground stock in our Citizen. Part is 4" long and .2494 diameters on both end with .294 diameter about .400 wide in middle. getting parts that ore bowed .003. Will PH material run straighter? if so what spec?

Thanks

17-4ph means precipitation hardened. It's not like 4140ph pre hardened. 17-4ph condition a is fairly common at 28-32 hrc. Condition h900 is popular as well, great to machine bitch to tap.
 








 
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