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

writes:

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

I wrote a computer numbercrunching solution to do this for flocking
pipe with fusion-bonded epoxy. Get the right temperature for long
enough but not "burn" the pipe surface (essentially - if the "white"
blasted surface develops any temper colour patina).

I myself do not know of any other way.

Mine is a mechanistic model based on heat transfer being a random
jumping process. Not mathematical at all.

Whether current finite element packages could do this easily for your
part ? As never tried.

This is a transient-state / "unsteady state" heat calculation /
computation. Which "notoriously" do not have "on-paper" formulae to
enable answers to be worked out, apart from some very simple cases
which fall way short of most practical engineering applications.

Rich Smith

On Wed, 19 Sep 2018 16:40:30 -0700, 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?

Yes I do. Until last July 1st when health problems forced my
retirement, I owned Tellico Induction Company Inc. Or Tnduction. We
manufactured a line of Royer-type induction heaters ranging from 1500
watts to 10kW. Our 2500 watt heater would have done the job just
fine.

I have a set of spreadsheets to compute stuff like this. Assuming
you're starting at 70 deg and ignoring Stephan-Boltzman radiative
losses and ignoring heat conducted away by the adjacent steel, it will
take approximately 260 seconds to reach 900 deg F with a 2500 watt
heater. So I'd guess about 300 seconds. Our 3500 watt unit would
reduce the time to about 190 seconds.

Normally at this point I'd go into the lab, prepare a test specimen
duplicating your taper and actually time the heat rate. Unfortunately
I've sold my lab and shop.

My only question is that if you're going to hold the small end at 900
deg for a period of time, how are you going to keep the heat away from
the heat affected zone?
John DeArmond
http://www.neon-john.com
http://www.tnduction.com
Tellico Plains, Occupied TN
See website for email address

On Wed, 19 Sep 2018 22:35:28 -0400, Neon John wrote:

On Wed, 19 Sep 2018 16:40:30 -0700, 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?

Yes I do. Until last July 1st when health problems forced my
retirement, I owned Tellico Induction Company Inc. Or Tnduction. We
manufactured a line of Royer-type induction heaters ranging from 1500
watts to 10kW. Our 2500 watt heater would have done the job just
fine.

I have a set of spreadsheets to compute stuff like this. Assuming
you're starting at 70 deg and ignoring Stephan-Boltzman radiative
losses and ignoring heat conducted away by the adjacent steel, it will
take approximately 260 seconds to reach 900 deg F with a 2500 watt
heater. So I'd guess about 300 seconds. Our 3500 watt unit would
reduce the time to about 190 seconds.

Normally at this point I'd go into the lab, prepare a test specimen
duplicating your taper and actually time the heat rate. Unfortunately
I've sold my lab and shop.

My only question is that if you're going to hold the small end at 900
deg for a period of time, how are you going to keep the heat away from
the heat affected zone?
John DeArmond
http://www.neon-john.com
http://www.tnduction.com
Tellico Plains, Occupied TN
See website for email address
Thanks for the info John. I'm not sure how I'll keep the heat from
moving along the part and if I really care. I'm afraid that if the
whole part is heat treated it may warp. If the very end just gets
toughened a bit then I'll be happy.
Eric

wrote in message
...
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

Do you have an infrared thermometer that reads that high? You could
heat the end of a reject or test piece with acetylene until the red
glow is visible in dim light and measure the temperature profile down
the taper.

https://www.amazon.com/Perfect-Prime...gh+temperature

-jsw

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

On Thu, 20 Sep 2018 05:39:39 -0700 (PDT), "
wrote:

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
Greetings Dan,
You are correct about getting the full hardness. But I have done this
before with a torch and the steel does get substantially nharder and
tougher in just a rew minutes. The customer is not requiring the
hardened end but it would make the part better. Sending the parts out
for heat treatment may cause them to warp as they are long and the
other end is pretty skinny.
Eric

On Wed, 19 Sep 2018 16:40:30 -0700, 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

Why not simply stick em into a broiler?

__

"Poor widdle Wudy...mentally ill, lies constantly, doesnt know who he is, or even what gender "he" is.

No more pathetic creature has ever walked the earth. But...he is locked into a mental hospital for the safety of the public.

Which is a very good thing."

Asun rauhassa, valmistaudun sotaan.


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On Wednesday, September 19, 2018 at 4:39:21 PM UTC-7, 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

I have done similar things with NiTi tubes. Clamp the need to be cold section into a coffee can and fill with water. Use a non contact IR thermometer to measure part temperature. Making a thermal couple work inside and induction heater magnetic field is an art.

If you want to analyze the process I have done similar using 1-D finite difference formulations implemented in matlab script. One gets the time varying and steady state solution

On Wednesday, September 19, 2018 at 4:39:21 PM UTC-7, 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