Simple method of measuring thicknesses of surface-hardened layers by laser ultrasonic technique

We proposed a simple non-contact inspection method using laser ultrasonic technique to measure the thickness of surface-hardened layer. This measurement is based on dependence surface-wave velocity hardened layers. In this case, it essential with wavelength comparable However, not easy selectively generate surface waves desired wavelength. Thus we where are extracted bandpass electrical filters. simpler than conventional one dispersion because directly obtained from measured temporal waveforms. applied layers and showed that results were in good agreement by numerical results.