焊缝双壁或多层透照时灵敏度的评价

讨论压力容器或管子环焊缝采用双壁单影或带附加厚度的多层透照法时像质计(IQI)灵敏度的评价，并揭示像质评价的本质。对我周JB4730，GB3323和美国ASME标准的不同之处进行了剖析比较，提出双壁单影和多层透照时像质计灵敏度应从焊接质量验收角度考虑，应基于单壁焊缝厚度即检验区厚度而不是射线穿透总厚度进行评价的观点，指出双壁单影和多层透照中像质计置于片侧的局限性。为国内标准的修订和向国际接轨提供参考。

SENSITIVITY EVALUATION IN DOUBLE-WALL OR MULTI-LAYER RADIOGRAPHIC INSPECTION OF WELDS

A discussion was given on IQI (image quality indicator) sensitivity evaluation in double wall single image or multi layer radiographic inspection of the girth welds in pressure vessels or pipes. The essentiality of image quality assessment was revealed. The standards JB 4730, GB 3323 and ASME were compared and analyzed and it was proposed that IQI sensitivity in double wall single image or multi layer radiography should not be specified and evaluated based on the total penetrated thickness of radiation but the single wall weld thickness(the thickness of the inspected area). The limitation of positioning IQI on film side in the inspection was also pointed out. It was intended to give a reference for revising the related Chinese standards and linking up them with international standards.