Rapid inspection using integrated ultrasonic arrays

Welds in high-quality products are subjected to extensive ultrasonic inspection during manufacture and in-service. The time and efficiency of the scan is important for both financial and quality assurance considerations. This has led to a BRITE-EuRAM programme, to develop methods for performing rapid quality weld inspection with a target reduction of 75% in inspection time. To achieve this, a large (128 mm) cost-effective self-contained ultrasonic array system was developed which allows rapid inspection, when compared to a single-probe system, and real-time images to aid in the detection and identification of flaws, The scanning and control electronics were integrated with a piezo-polymer array for wide bandwidth and to optimise signal-to-noise ratio, cost and flexibility. The self-contained head allows it to be used with a wide range of conventional equipment, for increased speed of coverage, as well as for imaging. Examples of A-scans and images obtained using the array on practical samples are presented. The standard design has an operational acoustic frequency band of2 to 5 MHz which covers the frequencies required for weld inspection but this can be raised (for improved resolution or for thickness gauging) or lowered (for attenuating materials) as required.