Session: 10-01: Nonlinear Ultrasonic Techniques for NDE I

Paper Number: 149234

149234 - Measurement of Third-Order Ultrasonic Nonlinearity Parameter in Heat-Treated Alloy 690 Using Pule-Echo Method 

Abstract: 

The generation of harmonics in propagating ultrasonic waves is due to ultrasonic nonlinearity, which is caused by the nonlinear elastic interaction between material and propagating ultrasonic waves. This ultrasonic nonlinearity is known to be effective in the evaluation of material degradation, and many cases studies have been conducted. In most studies, the second-order nonlinearity parameter, defined using the second harmonic component generated during the ultrasonic propagation, is measured by through-transmission method. However, the pulse-echo method is highly advantageous in field applications. In the aspects of field applications, pulse-echo method is highly advantageous, but the second harmonic component is difficult to receive using this method due to phase inversion effect. Therefore, this study focuses on the use of the third harmonic component that is not affected by the phase inversion when the wave is reflected and proposes a pulse-echo method to measure the third ultrasonic nonlinearity parameter to assess heat-treated Alloy 690. The validity of the proposed method was verified in Alloy 690 specimens heat-treated for up to 200 hours at 700 °C. For comparison, the second-order nonlinearity parameter was measured using through-transmission method and the ultrasonic velocity and attenuation coefficient, which are linear parameters, were also measured to compare their sensitivities with those of the nonlinear parameters. Additionally, the tensile and yield strengths were obtained, and the results were correlated with the third-order ultrasonic nonlinearity parameter. In these results, the trend of the third-order nonlinearity parameter showed high correlation with the tensile and yield strengths. The second-order nonlinearity parameter measured by through-transmission method showed the same trend as that of the third-order nonlinearity parameter measured by pulse-echo method. In the aspect of sensitivities, the attenuation coefficient was greatly reduced compared with the ultrasonic nonlinearity parameter, and the trend of the ultrasonic velocity showed almost no change. These results confirm the validity of the proposed technique and that the third-order nonlinearity parameter is an effective indicator of thermal aging of Alloy 690 material which is expected to be practically used in the field because of its excellent field applicability.

Presenting Author: Sung-Jun Bang Hanyang University

Presenting Author Biography: Sung-Jun Bang is in PhD program in ISNDE (Intelligent Sensing & Nondestructive Evaluation) Lab at Hanyang University. He has been studying Ultrasonic Nonlinearity Parameter for more than 3 years. He is currently, studying about the third-order ultrasonic nonlinearity parameter measured by pulse-echo method on various materials that are used in the industries.

Authors:

Sung-Jun Bang Hanyang University
Dong-Gi Song Korea Atomic Energy Research Institute
Kyung-Young Jhang Hanyang University