Experimental study of the corrosion effect on the elastic properties of steel plates by ultrasonic method

Abstract

The corrosion effect on the acoustics and elastics parameters of steel plates corroded are studied by ultrasonic techniques. A new method is developed to measure these parameters as a function of the immersion time in the acid solution HCl (corrosion). Lamb waves (plate driven mechanical waves) were selected to perform the different types of inspection required. Their high level of sensitivity to variations in thickness made it a logical choice to achieve the objectives of this work as well as a relevant and interesting research topic. They also offer the advantage of allowing the inspection of a part faster than conventional volume wave methods (point - by - point inspection). The dispersion of the Lamb modes generally causes problems of interpretation of the signals but offers, however, certain advantages as regards the measurement of thickness via certain measurements of the speed of these modes. The Ultrasonic testing is based on the measurement of ultrasonic parameters ie longitudinal and transversal velocities in the corroded steel samples. The corrosion resulting from corroded steel is analyzed by monitoring changes in ultrasonic parameters. The obtained results show that the proposed method is very efficient to characterize the corrosion effect on the elastic properties of steel plates, for acoustic characterization purposes.