| 摘要 |
PROBLEM TO BE SOLVED: To diagnose degradation condition in substantially non-destructive manner by taking a sample out of used cable, and measuring hardness of minute area of the taken sample. SOLUTION: Minute hardness and disconnection/extension are measured with multiple reference samples wherein degradation conditions differ each other in step manner, and with this, the relation between the minute hardness and disconnection/extension is obtained, as degradation correlation information representing degradation degree of a cable 10. Then a sample is taken. The sample is taken from a PVC sheath 13. The sample used for measurement is a very small piece whose side is about a few hundred ofμm, so, diagnostics is performed in substantially non-destructive or with minimum damage. Measurement is performed with a dynamic ultra-fine hardness gage, etc., and decision is made by referring the measured minute hardness to the degradation correlation information which was obtained before.
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