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Determination of Sub-Surface Microstructure States by Micromagnetic NDT

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

Abstract

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.

Keywords

Residual Stress Nondestructive Test Shot Peening Hardness Profile Microstructure State 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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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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