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Homework Help: Heat transfer Question

  1. Mar 20, 2008 #1
    If I had a piece of steel 0.25" thick 1 meter wide and 1 meter long and it was at 100 deg C and it was immersed in a bath of zinc at 460 deg C how long would it take to heat the piece of steel to 460 deg C?

    Would this be down the lines of Fourier's Law of conduction?

    q= 42*1*(460-100)/0.0635?

    FYI... I am a process engineer at a steel company and my son directed me to this sight for help
    Last edited: Mar 20, 2008
  2. jcsd
  3. Mar 20, 2008 #2


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    Hi loopster, welcome to PF. A simple way to estimate the heating time is


    where [itex]L[/itex] is the characteristic length and [itex]D[/itex] is the thermal diffusivity. I'd take half the thickness, 1/8", as the characteristic length because the zinc bath is on both sides. It looks like the thermal diffusivity of steel is about 10-5 m2/s = 0.0155 in2/s. This predicts the heating time to be about a second. Is this helpful?

    Incropera & DeWitt's Fundamentals of Heat and Mass Transfer is a great reference if you have to solve a lot of these types of problems.
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