On Wednesday, September 19, 2018 at 7:39:21 PM UTC-4, wrote:
I have a small run of parts that have a #3 Morse taper on one end. At
the small end of the taper is a straight diameter that's .700 diameter
by .600 long. The material is 17-4 PH stainless. I want to harden the
small end only. To do this it must be heated to 900 degrees F and held
there for a while. I was wondering if a 2000 watt induction heater
would be up to the task. I know there are many variables but there
must be a minimum amount of power needed. Anybody know?
Thanks,
Eric

The big problem that I see is avoiding hardening the rest of the part.
I would suggest you think about why you do not want the entire part hardened and try to think about how you could live with the entire piece being hard.

As I remember to harden 17-4 ph you heat to 900 F and hold it at that temp for an hour.

Dan