Development of Ultrasonic Inspection Technique for Steel Billets with High Acoustic Attenuation

Abstract

Various nondestructive testing have been applied for steel products in manufacturing processes. Ultrasonic inspection is an important method to evaluate inclusions in rolled billets. Conventional ultrasonic transducer with a flat piezoelectric element is used for the inspection. However, ability of inspection for a part of chromium stainless steel billets with coarse grain is insufficient with comparison to the ability for carbon steel billet. This paper describes a result of development of new ultrasonic transducers for the billets with coarse grain. Numerical analysis with finite element method was carried out to make sure a best frequency and wave shape. Two transducers are designed and confirmed advantages over the conventional transducers.