バルクハウゼンノイズ法によるロータ材3Ni-Cr-Mo-V鋼の焼戻し脆化の非破壊評価

概要

論文の詳細を見る
A magnetic nondestructive evaluation technique, the Barkhausen noise method was applied to the estimation of temper-embrittlement of 3Ni-Cr-Mo-V rotor steel. The results are summarized as follows. (1) Two parameters, Vickers hardness (H_v) and induced peak voltage ( V_p), closely related to the macroscopic magnetic permeability (μ), showed little change throughout the 400℃ aging treatment. (2) Among the parameters of Barkhausen noise, BHN rms voltage (V_<BHN>) and BHN peak height (P_<BHN>) increased, while the normalized BHN spectrum height (P_<max>/P_5) decreased. All of these parameters, V_<BHN>, P_<BHN> and P_<max>/P_5 were closely correlated with the embrittlement of rotor steel, i. e., Charpy absorbed energy E_c 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.
社団法人日本機械学会の論文
1990-07-25