17-7 ss wire heat threating options

[MrGQ]

Hello to all Engineers!
We have two spring makers proposal using 17-7 ss wire, condition C to be meet blue print load requirement: Option 1: heat threat to 900F for 30 minutes and Option 2: Heat threat to 750F for 1 hour. Which one is right? Your comments Please, if any one had similar project.
Thanks.

 

[NickE]

None of the above.

the standard ultra-high strength aging heat treat of 17-7ph is H900 (1hr@900F)

I have the feeling that 750 is below the activation energy for the preciptation to occur. While 900F for 1/2 hr might get what you want, it may not develop the proper distribution and size of the preciptates.

 

[TVP]

As NickE said, 900 F for 1 hour is the usual requirement (SAE J217, SAE AMS 2759/3C). 750 F is DEFINITELY too low, no matter how long the time.

 

[MrGQ]

Gentlemen, Thank you for information.