Re: ASME Cal Blocks ----------- Start Original Message ----------- : When would you use the 2% notches on the ASME cal blocks? Are they there for comparing to undercut signals? : Is there ever a time when they are used when constructing the DAC? : John ------------ End Original Message ------------
According to ASME Sec. V 2000, Articles, 4 & 5, 2% notches are used for vessel examinations. Side drilled holes are generally used for DAC construction for vessel calibrations with the notch location and amplitudes marked on the screen. ASME Sec. V, Article 4, B-465 discusses the amplitude responses from square notches at the opposite side of the block from various angles. B465.2 states that a 45º shear wave angle may give you an indication of 2-1 above DAC on a square notch, whereas a 60 º may give you an indication of only ½ DAC and that indication from that notch shall be considered when evaluating reflectors at the opposite surface. Notches are used for calibration of piping and tubing materials. Now depending on which article you are using, whether it is Article 4 or Article 5, the notch sizes vary and will be used for DAC construction. Side drilled holes may be used provided you can demonstrate equivalent or greater sensitivity than that produced by notches. Article 4, requires notches to be between 8%t and 11%t. Article 5 requires notches to be 5%t or 0.004, whichever is greater.