Development and Evaluation of a Workpiece Analyzer for Industrial Furnaces

  • P. Kotidis
  • J. Woodroffe
  • J. Shah
  • T. Schultz

Abstract

The traditional method of determining the temperature of heat-treated workpieces in industrial furnaces is to measure surface temperature with radiation pyrometers or local temperature with contact thermocouples. Contact thermocouples have limited use because they damage the workpiece in a continuous process or require drilling of a hole in the workpiece for batch operation. Radiation pyrometers are used for noncontact surface temperature measurements, but suffer from inherent inaccuracies because of interference by radiation from furnace hot walls and gases in the furnace atmosphere and varying emissivity of the workpiece during thermal processing. Dual-wavelength pyrometers are designed to provide independence from emissivity variations. However, they do not perform on non-gray-bodies, they have difficulty looking through non-gray windows, and they tend to measure background temperature when the background is hotter than the target. Multicolor pyrometers use algorithms to eliminate the variable emissivity problems with limited success and applicability. In addition, traditional nondestructive temperature measuring instruments lack the capability to measure temperature gradients in a workpiece, which are critical for uniform phase transformations. Moreover, the knowledge of the time at which this uniformity is achieved is important for process cycle time optimization. There is a need for an instrument which can measure surface temperature as well as average bulk temperature to provide knowledge of temperature uniformity in the workpiece. An instrument like that could provide substantial cost savings and near-term payback. The Surface Combustion, Inc. and Textron Defense Systems research team, under DoE support, has conceptualized such an instrument to be used as Workpiece Analyzer (WPA). 1,2 This paper describes results of an analytical study to determine the feasibility of this concept and preliminary experimental data of a bench scale demonstration.

Keywords

Combustion Furnace Attenuation Ferrite Austenite 

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References

  1. 1.
    U.S. Department of Energy, Phase 1 Final Report, Development and evaluation of a Workpiece Temperature Analyzer for Industrial Furnaces (1990).Google Scholar
  2. 2.
    U.S. Department of Energy, Phase 1-A Final Report, Development and evaluation of a Workpiece Temperature Analyzer for Industrial Furnaces (1991).Google Scholar
  3. 3.
    J.P. Reilly, A. Ballantyne, and J.A. Woodroffe, Modeling of momentum transfer to a surface by laser-supported absorption waves, AIAA J. 17:1098 (1979).CrossRefGoogle Scholar
  4. 4.
    J.A. Woodroffe, Pulsed-laser material interaction, in: “Gas Flow and Chemical Lasers,” Michele Onorato, ed., Plenum Publishing Co., New York (1984).Google Scholar
  5. 5.
    J.A. Woodroffe, J.C. Hsia, and A. Ballantyne, Thermal and impulse coupling to an aluminum surface by a pulsed Krf laser, Appl. Phys. Lett. 36:14 (1980).CrossRefGoogle Scholar
  6. 6.
    C. Duzy, J.A. Woodroffe, J.C. Hsia, and A. Ballantyne, Interaction of a pulsed XeF laser with an aluminum Surface, Appl. Phys. Lett. 37:542 (1980).CrossRefGoogle Scholar
  7. 7.
    J.F. Ready, “Industrial Applications of Lasers,” Academic Press, New York (1978).Google Scholar
  8. 8.
    H. Kolsky, “Stress Waves in Solids,” Dover Publications, Inc., New York (1963).Google Scholar
  9. 9.
    A.E.H. Love, “A Treatise on the Mathematical Theory of Elasticity,” Dover Publications, Inc., New York 4th ed. (1944).Google Scholar
  10. 10.
    I.A. Victorov, “Rayleigh and Lamb Waves,” Plenum Press, New York (1967).Google Scholar
  11. 11.
    A.M. Aindow, R.J. Dewhurst, and S.B. Palmer, Laser-generation of directional surface acoustic wave pulses in metals, Opt. Commun. 42:116 (1982).CrossRefGoogle Scholar
  12. 12.
    R.M. White, Generation of elastic waves by transient surface heating, J. Appl. Phys. 34:3559 (1963).CrossRefGoogle Scholar
  13. 13.
    D.A. Hutchins, R.J. Dewhurst, and S.B. Palmer, Directivity patterns of laser-generated ultrasound in aluminum, J. Acoust. Soc. Am. 70:1362 (1981).CrossRefGoogle Scholar
  14. 14.
    C.B. Scruby, R.J. Dewhurst, D.A. Hutchins, and S.B. Palmer, Quantitative studies of thermally generated elastic waves in laser-irradiated metals, J. Appl. Phys. 51:6210 (1980).CrossRefGoogle Scholar
  15. 15.
    W. Kaule, Method and apparatus for receiving ultrasonic waves by optical means, U.S. Patent 4,388,832 (1983) (assigned to Krautkramer-Branson, Inc.).Google Scholar
  16. 16.
    J.P. Monchalin, Optical detection of ultrasound, IEEE Trans. on Ultrasonics, Ferroelectrics and Frequency Control 33:485 (1986).CrossRefGoogle Scholar
  17. 17.
    G.S. Darbari, R.P. Singh, and G.S. Verma, Ultrasonic attenuation in carbon steel and stainless steel at elevated temperatures, J. Appl. Phys. 39:2238 (1968).CrossRefGoogle Scholar
  18. 18.
    E.P. Papadakis, L.C. Lynnworth, K.A. Fowler, and E.H. Carnevale, Ultrasonic attenuation and velocity in hot specimens by the momentary contact method with pressure coupling, and some results on steel to 1200°C, J. Acoust. Soc. Am. 52:850 (1972).CrossRefGoogle Scholar
  19. 19.
    A.M. Aindow, R.J. Dewhurst, D.A. Hutchins, and S.B. Palmer, Laser-generated ultrasonic pulses at free metal surfaces, J. Acoust. Soc. Am. 69:449 (1981).CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1994

Authors and Affiliations

  • P. Kotidis
    • 1
  • J. Woodroffe
    • 1
  • J. Shah
    • 2
  • T. Schultz
    • 2
  1. 1.Textron Defense SystemsEverettUSA
  2. 2.Surface Combustion, Inc.MaumeeUSA

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