For the production of highly stressed components, particularly for the aircraft and automotive industries, reliable examination of all billet material used is mandatory. Representative requirements of ASTM B594 standards class-A (1,2 mm flat bottom hole reflection) and class-B (2,0 mm flat bottom hole reflection) sensitivity are typically achieved.
This method allows testing of entire log except an outermost skin some 5 mm deep. To examine this skin layer further probes positioned at an angle to the log surface (angle beam testing) are required.
Helical ultrasonic testing is adjusted to detect centre cracks, inclusions and surface cracks. They are likely to be integrated in the production process but sometimes individual positioning is prefered.
This method requires substantial capital investment and rather long testing times per log than with linear testing. It is therefore applied only for particularly meticulous quality testing requirements.
Functional principle helical ultrasonic testing
Helical ultrasonic testing, capable for 70.000 tons of logs per year