Ultrasonic inspection of large Inconel 706 forgings
- General Electric Co., Schenectady, NY (United States)
An automated method to inspect large, high alloy, turbine rotor disk forgings using an ultrasonic pitch-catch technique is described. An in-process test of Inconel 706 (IN706) and stainless steel forgings is currently performed to specifically detect and size indications resulting from the manufacturing process that may be oriented perpendicular to the highest operating stress gradient. For rotating components, this orientation lies in the axial-radial plane of the forging. The forgings tested weigh up to 22,000 pounds and have a relatively coarse grain structure as compared to lower alloy steels and smaller forgings. The method uses two shear wave search units in transmit-receive mode. Radiation patterns from the two search units are directed at the axial-radial plane of the forging. As the forging is rotated, the search units are swept in unison across the surface of the forging until the entire test volume is inspected. Ultrasonic data is digitally acquired from a logarithmic flaw detector, displayed, recorded and automatically evaluated using a 486 PC computer. The inspection is optimized to attain the highest probability of detection with minimal false alarms. Indications are sized based on their reflected amplitudes and reported as an equivalent flat bottom hole size.
- OSTI ID:
- 64672
- Report Number(s):
- CONF-931193--; ISBN 0-931403-23-5
- Country of Publication:
- United States
- Language:
- English
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