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当胶片一试件距离为试件中缺陷直径 4倍以上时 ,由缺陷的射线照相对比度 (△ D)、衰减系数 (μ)以及试件无缺陷区的散射比 (n) ,即可求出该圆形缺陷的高度。但μ和 n值不易测得。为解决此难点 ,可利用放置在试件射源侧表面的对比试样 ,本文叙述有关的必需条件和对比试样的有效性。我们可在单次曝光的单张射线底片上 ,根据无缺陷区、缺陷区和对比试样三者黑度关系 ,较准确地测出缺陷高度。
When the distance between a film and a specimen is 4 times or more than the diameter of the defect in the specimen, the radiographic contrast (ΔD), the attenuation coefficient (μ), and the scattering ratio (n) of the defect-free area of the specimen can be obtained The height of the circular defect. However, μ and n values are not easy to measure. In order to solve this difficulty, a comparative sample placed on the side surface of the source of the test piece can be used. This article describes the necessary conditions and the validity of the comparative test piece. We can in a single exposure of a single radiograph, according to no defect area, defect area and the contrast between the three samples of black, the more accurate detection of defect height.