TWI

The non-destructive testing (NDT) aspects of the Qualistir project for the on-line quality control of friction stir welding in aluminium are described. Definitions are given for the following defects: voids, wormholes, lack of penetration, faying surface flaws and entrapped oxide. The development results are divided into four categories: conventional defect detection, ultrasonic velocity measurements, ultrasonic frequency measurements and ultrasonic noise distribution measurements. Two methods were demonstrated for determining the quality of friction stir butt welds: ultrasonic amplitude rejection for conventional defects and material noise ratio analysis for determining the depth of penetration of the correctly forged weld nugget.

4th International Symposium, 14-16 May 2003, Session 9A: Metallurgy & Performance 4, Paper 01