表2“双单法”中因遵照厚度涵义不一造成IQI灵敏度要求不一的实例mm表3“双双法”中因遵照厚度涵义不一造成IQI灵敏度要求不一的实例4．6其他问题4．61透照模式压力容器对接焊缝涉及到的透照模式可归纳成表人内透法中的中心直照法和斜照法（即垂直全景和倾斜全景）已是多年来环 Table 2 “double single” in compliance with the thickness of different definitions of IQI sensitivity caused by different requirements mm Table 3 “double-double method” in accordance with the thickness of different conception IQI sensitivity caused by different requirements 4.6 other issues 4 .61 Transillumination Modes The transillumination modes involved in pressure vessel butt welds can be summed up in the center direct illumination method and the oblique illumination method (ie, vertical panorama and oblique panorama) which have been around for many years