Dimensional Measurements and Material Characterization
This non-destructive measurement uses ultrasound in a frequency range up to 4 MHz. The transducer generates high energy pulses which travel through the material and are reflected by discontinuities and surfaces. A fast A/D converter measures the echoes and the DSP processes the delay time and signal strength. By comparison with a reference, material thickness and flaws can be detected.
The same technique as described above can be used to detect flaws like cracks and blow holes in welded joints, for example in pipelines.