Use ultrasonic testing equipment to test the metal hardened layer of carbon steel gears with different thicknesses. Set the sampling frequency of the high-speed acquisition card to 50MHz. Adjust the ultrasonic parameters of the testing signal to obtain the original ultrasonic pulse signals with different thicknesses. The time domain waveform of carbon steel gears with different hardened layer thicknesses is shown in Figure 1.
The frequency domain waveform of ultrasonic testing signal is obtained by fast Fourier transform of ultrasonic signals collected from hardened layers with different thicknesses. Figure 2 shows the frequency domain waveform of carbon steel gears with different hardened layer thicknesses.
