GB1343989A - Method and apparatus for ultrasonic non-destructive testing - Google Patents

Abstract

1343989 Acoustic flaw detection STAHLWERKE PEINE-SALZGITTER AG 19 April 1971 [30 April 1970] 26240/71 Heading H4D A method of testing sheet or strip material comprises using at least one scanning unit moved at an angle to the direction of feed of the material and which contains two ultrasonic transducers operating in a through transmission mode, wherein the ultrasonic energy to and from the transducers is inclined relative to the surface of the material. Transducers 4, 5, Fig. 2, are supported on an arm 6 biased against the test-piece 3 by a spring loaded scissors arrangement 7. This is carried on a carriage 8 driven along an I-beam 9, placed transverse to the feed direction, by a motor 14 via rack and pinion 16, 15. The I-beam is mounted at each end on fixed supports (19, Fig. 4, not shown) and may be raised or lowered thereon by a further drive, racks and pinions. The carriage has a cover 18 to deflect the water coupling medium into collecting trough 17 and is mounted on the beam by rollers 10, 11, 12, 13, some of which are spring loaded. As the carriage 8 is driven back and forth across the strip 2 it describes a zig-zag course, Fig. la, which covers as much of the surface as desired. A plurality of units may be provided across the test piece and a spray-gun provided to mark the position of every flaw, which position is also recorded on an analogue record. The carriage 8 may also be oscillated at a high frequency along the direction of feed in order to provide increased scanning coverage for a reduced transverse speed.