| 摘要 |
PROBLEM TO BE SOLVED: To nondestructively and accurately evaluate the degree of stabilization of the rust layer of a weather-resistant steel material by sampling the rust layer adhering to ferrite that is formed on the surface of a steel material and measuring the amount of mass change at a specific temperature or more of the sampled rust powder. SOLUTION: A rust layer that adheres to ferrite being formed on the surface of a steel material is sampled, the amount of mass change at a temperature that is equal to or more than 100 deg.C of the sampled rust powder is measured, and the degree of stabilization of the rust layer is evaluated. When rust is to be sampled, the sampling is made separately to each of surface and inner layers of rust. Then, the mass of rust per unit area (1 cm2) is found, then a rust-sampling area and the total amount of sampling (total mass) of sampled rust are determined, required rust is sampled from the determined sampling area, and thermal analysis is made to each sampled rust, thus evaluating the degree of stabilization of rust. The amount of mass change due to a temperature change within a range of 105 to 300 deg.C caused by amorphous quantity and thermal analysis is constantly correlated according to the analysis result of the amorphous quantity by the thermal analysis and X-ray diffraction method for rust being formed at various kinds of weather-resistant steels.
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