Nondestructive Evaluation of Embrittlement of 3Ni-Cr-Mo-V Rotor Steel by the Magnetic Barkhausen Noise Method

Mitsuo Obata, Yuichi Ito, Yasubumi Furuya, Katsumi Iijima, Yutaka Fukui

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

A magnetic nondestructive evaluation technique, the Barkhausen noise method was applied to the estimation of temper-embrittlement of 3 Ni-Cr-Mo-V rotor steel. The results are summarized as follows. (1) Two parameters, Vickers hardness (Hv) and induced peak voltage (Vp), closely related to the macroscopic magnetic permeability (μ), showed little change throughout the 400°C aging treatment. (2) Among the parameters of Barkhausen noise, BHN rms voltage (VBHN) and BHN peak height (PBHN) increased, while the normalized BHN spectrum height (Pmax/Ps) decreased. All of these parameters, VBHN, PBHN and Pmax/Ps were closely correlated with the embrittlement of rotor steel, i. e., Charpy absorbed energy Ec and ΔFATT. (3) Temper-embrittlement seemed to be closely correlated with impurity segregation at grain boundaries. From the results in (1) and (2) and the fact that the metallurgical microstructure did not change in the optical-microscope observation level, it is thought that the changes of BHN signals observed in this study mainly reflect the factor of impurity segregation at grain boundaries in the aging process.

Original languageEnglish
Pages (from-to)1677-1684
Number of pages8
JournalTransactions of the Japan Society of Mechanical Engineers Series A
Volume56
Issue number527
DOIs
Publication statusPublished - 1990 Jan 1
Externally publishedYes

Keywords

  • 3Ni-Cr-Mo-V Steel
  • Barkhausen Noise
  • Embrittlement
  • Impurity Segregation
  • Magnetic Testing
  • Material Evaluation
  • Nondestructive Testing
  • Rotor Steel

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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