Journal of the Korean Society for Heat Treatment (열처리공학회지)

The Korean Society for Heat Treatment (한국열처리공학회)
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Ultrasonic Nondestructive Evaluation of Microstructural Degradation in Artificially Aging Heat Treated 2.25CrMo Steel

인공 열화 열처리된 2.25CrMo 강의 미세조직 변화에 대한 초음파 비파괴평가

  • Byeon, Jai Won (Research Institute of Engineering and Technology, Korea University) ;
  • Kwun, S.I. (Division of Materials Science and Engineering, Korea University) ;
  • Park, Un-Su (Research Institute of NDE Technology, Seoul National University of Technology) ;
  • Park, Ik-Keun (Research Institute of NDE Technology, Seoul National University of Technology)
  • 변재원 (고려대학교 공학기술연구소) ;
  • 권숙인 (고려대학교 재료금속공학부) ;
  • 박은수 (서울산업대학교 비파괴평가기술연구소) ;
  • 박익근 (서울산업대학교 비파괴평가기술연구소)
  • Received : 2001.04.06
  • Published : 2001.03.31
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Abstract

Artificial aging was performed to simulate the microstructural degradation in 2.25CrMo steel arising from long time exposure at $540^{\circ}C$. It was found that the carbides became coarser and spheroidized as aging time increased. An attempt was made to evaluate the microstructural degradation in artificially aging heat treated 2.25CrMo steel by the ultrasonic attenuation and velocity measurements. Ultrasonic velocity was found essentially insensitive to the microstructural changes resulting from aging heat treatment. However, the ultrasonic attenuation was observed to increase with increasing aging time. Also, it was noticed that the change of ultrasonic attenuation with aging time was more sensitive at high frequency regions.

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Acknowledgement

Supported by : 한국과학재단