Title: Studies of the effect of surface roughness in the behaviour of ultrasonic signals in AISI-SAE-4340 steel: spectral and wavelets analysis

Authors: Antonio J. Salazar; Edda C. Rodríguez

Addresses: Department of Electronics and Circuits, University Simon Bolivar, Universidad Simón Bolívar, Caracas, Edificio de Física y Electrónica I (FEI), Tercer piso, Oficina 343, Valle de Sartenejas – Edo, Miranda, 1080-A. Apartado postal 89000, Venezuela. ' Department of Material Sciences, University Simon Bolivar, Universidad Simón Bolívar, Caracas, Edificio de Mecánica y Materiales, Valle de Sartenejas – Edo. Miranda, 1080-A. Apartado postal 89000, Venezuela

Abstract: This study reports the influence of surface roughness on the characterisation, through the use of ultrasonic signals, of AISI-SAE 4340 steel samples. The samples were prepared with varying surface roughnesses, applied through mechanical methods and measured using a Mitutoyo Surfest-211. A normal incidence direct contact pulse-echo method was applied, using transducers of 5, 7.5 and 10 MHz, all with a 0.375 inch diameter. Fundamental spectral and wavelet signal analysis allowed for quantitative determination of a number of characteristics. Specific behaviours were detected, which varied according to the frequency of the probe. The methods proved to be complementary to each other, which contributed for a more complete evaluation and characterisation of the samples. This study serves as an initial step in the development of a thorough quantitative characterisation method of materials with different internal and surface defectology. Further studies and their findings have been and will be presented in additional articles.

Keywords: ultrasonic testing; surface roughness; nondestructive testing; NDT; Fourier transform; wavelet transform; spectral analysis; steel; surface quality.

DOI: 10.1504/IJMMP.2011.043218

International Journal of Microstructure and Materials Properties, 2011 Vol.6 No.3/4, pp.224 - 235

Available online: 20 Oct 2011 *

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