Determination of Sub-Surface Microstructure States by Micromagnetic NDT

  • W. A. Theiner
  • I. Altpeter
  • R. Kern


The functional behaviour of many components is determined by the intrinsic properties — residual stresses and microstructure — of sub-surface near zones. Therefore, in order to improve the static and dynamic mechanical properties of these surface near states, mechanical and/or thermal treatments such as laser hardening, inductive hardening, case hardening, nitriding, grinding and shot peening are applied. Depending upon the work-piece/component and the employed technique and machining parameters, the residual stress- and microstructure states will be changed between a few micrometers and several millimeters. To control the quality of these subsurface near states, metallographic inspections, x-ray methods and hardness measurements have been applied. Because all these conventional testing methods are expensive, time consuming and not suitable for real time control,1–4 there is a considerable need of nondestructive testing (ndt) methods. So far ndt procedures are mainly restricted to eddy current methods,5,6 ultrasonic techniques7,8 and — in the case of ferromagnetic materials — micromagnetic techniques1,9–11.


Residual Stress Nondestructive Test Shot Peening Hardness Profile Microstructure State 
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  1. 1.
    Brinksmeier, E.; Schneider, E.; Theiner, W.A.; Tönshoff, H.K. Nondestructive Testing for Evaluating Surface Integrities. Annals of the CIRP 33 (1984) 2, 489–509Google Scholar
  2. 2.
    Field, M.; Kahles, J.F. Review of Surface Integrity of Machined Components. Annals of the CIRP 20 (1971) 2, 153–163Google Scholar
  3. 3.
    Field, M.; Kahles, J.F.; Cammett, J.T. A Review of Measuring Methods for Surface Integrity. Annals of the CIRP 21 (1972) 2, 219–238Google Scholar
  4. 4.
    Hauk, V.; Macherauch, E. Eigenspannungen und Lastspannungen. HTM-Beiheft, Eds., Carl Hanser Verlag, München 1982Google Scholar
  5. 5.
    Larsson, H. Testing of Hardening Depth by an advanced eddy current method. 3rd European Conference on Nondestructive Testing, 16–18 Oct. 1984, FirenceGoogle Scholar
  6. 6.
    Becker, R.; Rodner, Ch. Eddy current testing. IzfP-Bericht 820123-E, 1982Google Scholar
  7. 7.
    Good, M.S.; Rose, J.L. Measurement of thin case depth in hardened steel by ultrasonic pulse-echo angulation techniques, from: Nondestructive methods for material property determination. Plenum Press, New York and London 1983, 192–203Google Scholar
  8. 8.
    Mesure des gradients de dureté. Prospectus: CETIM 60304 Senlis Cedex, France, 1985Google Scholar
  9. 9.
    Rulka, R.; Pawlowski, Z. Evaluation of the Physical State of Surface Layers in Steel using Magnetic Noise Measurement. 9th World Conference on Nondestructive Testing, Paper 4AB, Melbourne 1979Google Scholar
  10. 10.
    Persch, H.; Theiner, W.A. Vorrichtung zum Messen von Werkstoffeigen-schaften. European Patent 831067103Google Scholar
  11. 11.
    Theiner, W.A.; Kern, R.; Conrad, R. Determination of surface Integrities by ferromagnetic quantities. First International Conference Surface engineering, Brighton 25–28 June 1985, Paper 25, 25–1–25–11Google Scholar
  12. 12.
    Theiner, W.A.; Willems, H.H. Determination of microstructural parameters by magnetic and ultrasonic quantitative NDE. from: Nondestructive methods for material property determination. Plenum Press, New York and London, 1983, 249–258Google Scholar
  13. 13.
    Schneider, E.; Altpeter, I.; Theiner, W.A. Nondestructive determination of residual and applied stress by micro-magnetic and ultrasonic methods, from: Nondestructive methods for material property determination. Plenum Press, New York and London, 1983, 115–122Google Scholar
  14. 14.
    Altpeter, I.; Kern, R. Einfluß ferromagnetisch 2ter Phasen auf die Eigenspannungsmessung und die Gefügecharakterisierung bei Nutzung magnetischer und magnetoelastischer Meßgrössen. IzfP-Bericht 840133-TW, 1984Google Scholar

Copyright information

© Plenum Press, New York 1987

Authors and Affiliations

  • W. A. Theiner
    • 1
  • I. Altpeter
    • 1
  • R. Kern
    • 1
  1. 1.Institut für zerstörungsfreie PrüfverfahrenSaarbrückenWest Germany

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