Acoustic Microscope Inspection of Cylindrical Butt Laser Welds
Presented work was made in order to develop the ultrasound technique for quality control of critical butt laser welds in automotive production. The set of powertrain assemblies was tested by high resolution acoustic microscopy method. The pulse-echo Tessonics AM 1102 scanning acoustic microscope was modified to accommodate cylindrical configuration of the parts. The spherically focused transducers with frequencies 15, 25 and 50 MHz were used; ultrasonic beam was focused on the joint area. Three-dimensional acoustic images were obtained and analyzed. The clear distinction between weld seam and remaining gap was demonstrated on the B- and C-scans representation. Seam depth varying from 0 up to 3.2 mm was measured along the weld. Different types of defects (porosity, cracks, lack of fusion) were detected and classified. The optimized analytical procedures for signal processing and advanced seam visualization were determined. The results were used as a basis for development of specialized instrumentation for inspection of this kind of parts in industrial environment. The technical requirements were established and the general design of new cylindrical acoustical scanner was made.
KeywordsLaser weld Butt weld Seam crack Acoustic microscopy Non-destructive evaluation
The authors are grateful to the Magna Powertrain AG & Co. KG (Lannach, Austria) for providing of samples, attention and support to the project.
- 1.ASM Handbook Volume 17: Nondestructive evaluation and quality control. ASM International 795 (1989)Google Scholar
- 3.Carrasco, M.A., Mery, D.: A robust algorithm for nondestructive testing of weld seams. In: Chen, C.H. (ed.) Ultrasonic and Advanced Methods for Nondestructive Testing and Material Characterization, pp. 635–658. World Scientific, New York (2007)Google Scholar
- 4.Maev, R.Gr.: Scanning Acoustical Microscopy. Theory and Application. Wiley, New York (2008)Google Scholar
- 5.Bisbee, L.H., Nottingham, L.: Longitudinal seam weld characterization by focused ultrasound. In: Prager, M., Tittley, R. (eds.) Proceedings of SPIE, vol. 2947, Nondestructive Evaluation of Utilities and Pipelines, pp. 88–99 (1996)Google Scholar