# Induction heating question

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
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snipped-for-privacy@whidbey.com writes:

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
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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.
-jsw
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On Wednesday, September 19, 2018 at 7:39:21 PM UTC-4, snipped-for-privacy@whidbey.com wrote:

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
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On Thu, 20 Sep 2018 05:39:39 -0700 (PDT), " snipped-for-privacy@krl.org"

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
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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
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On Wednesday, September 19, 2018 at 4:39:21 PM UTC-7, snipped-for-privacy@whidbey.com wro te:

I have done similar things with NiTi tubes. Clamp the need to be cold sect ion into a coffee can and fill with water. Use a non contact IR thermomete r to measure part temperature. Making a thermal couple work inside and i nduction heater magnetic field is an art.
If you want to analyze the process I have done similar using 1-D finite dif ference formulations implemented in matlab script. One gets the time varyi ng and steady state solution
On Wednesday, September 19, 2018 at 4:39:21 PM UTC-7, snipped-for-privacy@whidbey.com wro te:

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