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NON-DESTRUCTIVE MEASURING METHOD OF SECULAR DETERIORATION ASSOCIATED WITH CHANGE IN BRITTLENESS OF FERROMAGNETIC STRUCTURE MATERIAL

Patent code P03A003117
File No. IU040004JP01
Posted date Dec 22, 2003
Application number P2001-181135
Publication number P2002-372519A
Patent number P3513601
Date of filing Jun 15, 2001
Date of publication of application Dec 26, 2002
Date of registration Jan 23, 2004
Inventor
  • (In Japanese)高橋 正氣
Applicant
  • (In Japanese)岩手大学長
Title NON-DESTRUCTIVE MEASURING METHOD OF SECULAR DETERIORATION ASSOCIATED WITH CHANGE IN BRITTLENESS OF FERROMAGNETIC STRUCTURE MATERIAL
Abstract PROBLEM TO BE SOLVED: To provide a method for measuring the degree of secular deterioration of a ferromagnetic structure such as a pressure vessel of a nuclear reactor as the brittleness is changed in a pre-stage of cracking in a non-destructive manner by using a small magnetic yoke and an excitation power source.
SOLUTION: In the non-destructive measuring method of the secular deterioration of a ferromagnetic structural material as the brittleness of a material thereof is changed, the magnetic susceptibility χb of the ferromagnetic material is measured by a predetermined magnetic field intensity H with at least the coercive force Hc, and the embrittlement coefficient b is obtained from the expression b=χbH2 by using the magnetic susceptibility χb and the magnetic field intensity H. The correlation Hv=f(b) between the embrittlement coefficient b and the reference embrittlement factor (Vickers hardness Hv) changing corresponding to the change in brittleness of the ferromagnetic material similar to that of the ferromagnetic structural material to be measured is obtained in advance. The Vickers hardness Hv corresponding to each embrittlement coefficient b in the initial state and after the secular deterioration of the ferromagnetic structural material to be measured is obtained from the correlation Hv=f(b), and the Vickers hardness Hv is compared to quantitatively obtain the change in brittleness due to the secular deterioration of the ferromagnetic structure to be measured.
Outline of related art and contending technology (In Japanese)


従来の一般的な非破壊検査方法は全て、亀裂の発生とその進展を調べることを目的としていた。その結果、現在の非破壊検査方法の発展の方向は、できる限り小さい亀裂の発生を発見することにあり、かかる従来の非破壊検査方法では、亀裂が発生する前の段階での非破壊検査は行うことができなかった。

Field of industrial application (In Japanese)


この発明は、強磁性構造材またはそれを用いた強磁性構造体の、中性子線照射等による材料の劣化を非破壊的に測定して定量的に求める方法に関するものである。

Scope of claims (In Japanese)
【請求項1】
 
強磁性構造材の経年による脆性の変化を定量的に求めることにより、強磁性構造材の経年劣化を非破壊で測定する方法において、
強磁性材料の磁化率χbを保磁力Hc以上にて所定の磁界強度Hで測定し、
前記磁化率χbと前記磁界強度Hとから次式
b=χbH2
により脆化係数bを求めるものとし、
あらかじめ、前記強磁性構造材と同種の前記強磁性材料についての前記脆化係数bとその強磁性構造材の脆性の変化に対応して変化する基準脆化因子との相関関係を得ておき、
経年劣化測定対象の前記強磁性構造材について、初期状態および経年劣化後の前記脆化係数bの値を求めてそれらの値に各々対応する前記基準脆化因子の値を前記相関関係から求め、
それらの基準脆化因子の値を比較して、前記経年劣化測定対象の強磁性構造材の経年による脆性の変化を定量的に求めることを特徴とする、強磁性構造材の脆性の変化に伴う経年劣化の非破壊測定方法。

【請求項2】
 
前記基準脆化因子が硬度であることを特徴とする、請求項1記載の強磁性構造材の脆性の変化に伴う経年劣化の非破壊測定方法。
IPC(International Patent Classification)
F-term
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