厚度差达到20 mm的焊接接头, 同一透照长度内通常要按不同厚度范围分别做几次曝光。设计制作了铅倾斜面屏蔽板, 将其固定在射线机射线窗口上, 可不同程度地屏蔽射线, 使射线在穿过不同厚度焊接接头后, 到达胶片上的射线基本一致。试验证明, 该方法所摄大厚度差焊接接头底片的黑度和灵敏度均符合标准要求, 提高了一次曝光的检测厚度范围, 提高了工作效率。

The welding joints with thickness difference of 20 mm shall be exposed for several times respectively according to different scopes of thickness within the same length of transmission in radiography. We designed and manufactured the shielding panel of lead inclined plane and fixed it on the ray window of ray machine to shield some rays in various degrees. After penetrating the welding joints with different thicknesses, the rays reached the film being basically in accordance with each other. Among the welding joints with thickness difference of 20 mm, the blackness and sensitivity are all in conformity with the standard requirements. When the inspected thickness scope for exposure is increased once, the inspection efficiency can be enhanced twice.