Nondestructive Evaluation of Residual Life of 1Cr-1Mo-0.25V Steel by Reversible Magnetic Permeability

  • K. S. Ryu (Div. of Electromagnetic Metrology, Korea Research Institute of Standards and Science) ;
  • S. H. Nahm (Div. of Industrial Metrology, Korea Research Institute of Standards and Science) ;
  • Kim, Y. I. (Div. of Chemical Metrology and Materials Evaluation, Korea Research institute of Standards and Science) ;
  • K. M. Yu (Div. of Electromagnetic Metrology, Korea Research Institute of Standards and Science) ;
  • Kim, Y. B. (Div. of Electromagnetic Metrology, Korea Research Institute of Standards and Science) ;
  • Y. Cho (Dept. of Physics, Hannam University) ;
  • D. Son (Dept. of Physics, Hannam University)
  • 발행 : 2000.09.01

초록

We present a new procedure to evaluate the residual life of 1Cr-1Mo-0.25V steel by reversible magnetic permeability. The method is based on the existence of the first harmonics in the differential magnetization around the coercive force. The apparatus is based on the detection of the voltage induced in a coil using a lock-in amplifier tuned to a frequency of the exciting one. Results obtained for the first harmonics and Vickers hardness on the aged samples show that the peak interval of reversible permeability and Vickers hardness decrease as ageing time increases. The correlation between Vickers hardness and the peak interval of the reversible permeability could well be used to evaluate the residual life of 1Cr-1Mo-0.25V steel, nondestructively.

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