ASTM A388:19 pdf download

ASTM A388:2019 pdf download.Standard Practice for Uitrasonic Examination of Steel Forgings.
9. Procedure
9. 1 General:
9.1.1 As far as practicable, subject the entire volume of the forging to ultrasonic examination. Because of radii at change of sections and other local configurations, it may he impossible to examine some sections of a forging.
9.1.2 Perform the ultrasonic examination after heat treatment for mechanical properties (exclusive of stress-relief treatments) hut prior to drilling holes, cutting keyways, tapers, grooves, or machining sections to contour. If the configuration of the forging required for the treatment for mechanical properties prohibits a subsequent complete examination of the forging, it shall be permissible to examine prior to treatment for mechanical properties. In such cases, reexamine the forging ultrasonically as completely as possible after heat treatment.
9.1.3 To ensure complete coverage of the forging volume, index the search unit with at least 15 % overlap with each pass.
9.1.4 For manual scanning, do not exceed a scanning rate of
6 in./s [150 mm/si.
9.1.5 For automated scanning, adjust scanning speed or instrument repetition rate, or both, to permit detection of the smallest discontinuities referenced in the specification and to allow the recording or signaling device to function. At no time shall the scanning speed exceed the speed at which an acceptable calibration was made.
9.1.6 If possible, scan all sections of forgings in two perpendicular directions.
9.1.7 Scan disk forgings using a straight beam technique from at least one flat face and radially from the circumference, whenever practicable.
9.1.8 Scan cylindrical sections and hollow forgings radially using a straight-beam technique. When practicable, also examine the forging in the axial direction.
9.1.9 In addition, examine hollow forgings by angle-beam technique from the outside diameter surface as required in
9.3.1.
9.1.10 In rechecking or reevaluation by manufacturer or purchaser, use comparable equipment, search units, frequency, and couplant.
9.1.1 1 Forgings may be examined either stationary or while rotating in a lathe or on rollers. If not specified by the purchaser, either method may he used at the manufacturer’s option.
9.2 Straight- Beam Examination:
9.2.1 For straight-beam examination use a nominal 2¼ MHz search unit whenever practicable: however, 1 MHz is the preferred frequency for coarse grained austenitic materials and long testing distances. In many instances on examining coarse grained austenitic materials it may be necessary to use a frequency of 0.4 MHz. Other frequencies may he used if desirable for better resolution, penetrability, or detectability of flaws.
9.2.2 Establish the instrument sensitivity by either the reflection, reference-block technique, or DGS method (see Appendix X3 for an explanation of the DGS method).