ASME SECTION V的比较试片

T-262.2 Step Wedge Comparison Films. Step wedge comparison films shall be verified prior to first use, unless
performed by the manufacturer, as follows: (a) The density of the steps on a step wedge comparison film shall be verified by a calibrated densitometer. (b) The step wedge comparison film is acceptable if the density readings do not vary by more than ±0.1 density units from the density stated on the step wedge comparison film.

T-262.3 Periodic Verification.
(a) Densitometers. Periodic calibration verification checks shall be performed as described in T-262.1 at the beginning of each shift, after 8 hr of continuous use, or after change of apertures, whichever comes first. (b) Step Wedge Comparison Films. Verification checks shall be performed annually per T-262.2.

上述两段话校准周期一个是第一次使用前；一个是每年； 这两种在 ASME section V中的比较试片在中国不常用，但在美国是常用的，在ASNT中学习中也看到该试片的用途！