You will have an easier time finding it if you use the correct name
15-5 ph.
Sorry about that. There is also other grades of Precipitation
Hardening ( PH ) stainless. 17-4 is one of them.

I was also wrong about the heat treat. 900 degrees F ( not C ) for
an hour and air cool is a common heat treat. Typically gets 200 ksi
and C 46 hardness ( from AK steel web site ).

I also did a bit more looking. Custom 450 stainless from Carpenter
Technology is essentially the same steel.


Dan