这种情况下，像质计如何选用。

if the thickness to be radiographed exceeds the design thickness of the finished piece, the penetrameter (IQI) size shall be based on a thickness which does not exceed the design thickness of the finished piece by more than 20% or 1⁄4 in. (6.35 mm), whichever is greater. In no case shall
the penetrameter (IQI) size be based on a thickness greater than the thickness to be radiographed.

学习了，

      工艺如果要求机加工前50mm时拍片，就应按50mm选择像质计，才能体现当下检测时的像质计灵敏度，评定时按45mm评定。
       如果您按45mm选择像质计未尝不可，只不过提高了检测要求。

{:soso_e163:}学习了