A Study on the Evaluation of Mterial Degradaion for 2.25Cr-1Mo Steel using Ultrasonic Attenuation Characterization

  • Kim, Chung-Soek (Research Institute of NDE Technology, Seoul National University of Technology) ;
  • Park, Ik-Keun (Research Institute of NDE Technology, Seoul National University of Technology) ;
  • Park, Un-Su (Research Institute of NDE Technology, Seoul National University of Technology) ;
  • Kim, Hyun-Mook (Department of Mechanical Engineering, Graduate School, Hanyang Univ.) ;
  • Kwun, Sook-In (Division of Materials & Engineering, Korea Univ.) ;
  • Byeon, Jai-Won (Research Institute of Engineering and Technology, Korea Univ.)
  • Published : 2001.10.01

Abstract

In significant number of energy-related facilities for like thermal power plant or petro-chemical industry, CrMo steels are widely used energy conversion industries. However, these materials undergo precipitation of carbides or intermetallic compounds into grain boundary and change of internal microstructure such as coarsening of precipitation, decrease of solute elements and impurity segregation under more severe service conditions, which results in deterioration of inherent superior material characteristics. In this study, it was verified experimentally the feasibility of the aging degradation evaluation for degraded 2.25Cr-lMo steel specimens prepared by isothermal aging heat treatment at 63$0^{\circ}C$ by high frequency longitudinal ultrasonic and surface SH wave investigating the change of attenuation coefficient analyzed by spectral analysis. Attenuation coefficient had a tendency to increase as degradation proceeded.

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