ASTM A 388/A 388M

This practice covers the examination procedures for the contact, pulse-echo ultrasonic examination of heavy steel forgings by the straight and angle-beam techniques. An ultrasonic, pulsed, reflection type of instrument shall be used and shall provide linear presentation for at least 75% of the screen height. The 5% linearity referred to is descriptive of the screen presentation of amplitude. The electronic apparatus shall contain an attenuator, search units, transducers, couplants, reference blocks, and DGS scales. The forging shall be machined to provide cylindrical surfaces for radial examination in the case of round forgings. The ends of the forgings shall be machined perpendicular to the axis of the forging for the axial examination. Faces of disk and rectangular forgings shall be machined flat and parallel to one another. The procedures to be performed are as follows: ultrasonic examination of the forgings; straight-beam examination with establishment of the instrument sensitivity and calibration either by the reflection, reference-block technique, or DGS method; and angle-beam examination used for rings and hollow forgings.