In conventional ultrasonic nondestructive condition monitoring, testing personnel use their testing experience to interpret defects while analyzing the ultrasonic echo. Due to the coarse structure of the material, the ultrasonic wave attenuates more, so it sometimes gives a false impression of a defect and provides unreliable results. The conventional inspection method is too subjective and relies heavily on the effectiveness of testing personnel, so the inspection reliability is low. To overcome these limitations, a multi-interrogation ultrasonic technique and the correlation of different parameters such as attenuation, acoustic velocity and grain size with material characteristics are suggested in this document.1 Introduction Non-destructive testing (NDT) is the testing of materials, surface or interior defects or metallurgical conditions, without making it unfit for service. There are various NDT methods for inspecting the internal defects of complex surface parts, for example, radiography, vortex flow, ultrasound, etc. Among these testing techniques, ultrasonic testing plays an important role due to its strong penetration, good direction, high sensitivity, low overall comparative cost and being harmless to human body and parts material. Ultrasound [1, 2, 3, 4] is a highly effective non-destructive condition monitoring method that can detect even incipient failures. Therefore, the mean time between failures (MTBF) increases through proactivity and reduces the mean time to repair (MTTR) improving problem-solving capabilities. Ultrasonic non-destructive testing methods [5] play an important role in the physical characterization of technical materials and in the evaluation of their quality and functionality in structures. In a wide range of different NDT methods... half of paper......s, NDT and E International (2008).[10]. Bohren Craig F., Huffman Donald R.: Absorption and scattering of light by small particles, Wiley, 2007.[11]. Lavender JD: Ultrasonic testing of steel castings, Steel Castings Research and Trade Association, England, 1976.[12]. Napolitano RE: ASTM Grain Number Measurement, Materials Science and Engineering, Lowa State University.[13]. Hyun Lee Joon: Nondestructive Characterization of Metal Matrix Composite by Ultrasonic Measurement, Peragmon (1995).[14].http://www.ndted.org/EducationResources/CommunityCollege/Ultrasonics/Physics/attenuation.htm. Community College, n.d. Online.[15]. Anson LW, Chivers RC and Puttick. E.: On the feasibility of detecting pre-crack fatigue damage in metal matrix composites using ultrasonic techniques, Elsevier Science Limited: Composites Science and Technology (1995).