OBRABOTKAMETALLOV Vol. 28 No. 2 2026 193 EQUIPMENT. INSTRUMENTS References 1. Sangame B.B., Reddy Y.P. Investigation on eff ect of diff erent types of inoculants on the solidifi cation of ductile cast iron using thermal analysis. Multidiscipline Modeling in Materials and Structures, 2024, vol. 20 (6), pp. 995– 1012. DOI: 10.1108/MMMS-03-2024-0084. 2. Benini L., de Paula P.P.R., Tavares S.S.M., de Sá Carnerio F., Noris L.F., da Conceição B.M., Júnior J.M.M. Evaluation of austempered ductile iron end milling by magnetic Barkhausen noise and x-ray diff raction methods. Ultrasonic non-destructive property prediction framework for spheroidal graphite iron castings Digvijay Mhamane 1, a,*, Anand Bewoor 2, b 1 Department of Mechanical Engineering, Zeal College of Engineering and Research, Narhe Pune, Savitribai Phule Pune University, Pune – 411041, Maharashtra, India 2 Cummins College of Engineering for Women, Pune – 411052, Maharashtra, India a https://orcid.org/0000-0002-3277-0443, digvijay.ndt@gmail.com; b https://orcid.org/0000-0001-9329-3807, anand.bewoor@cumminscollege.in Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2026 vol. 28 no. 2 pp. 179–195 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2026-28.2-179-195 ART I CLE I NFO Article history: Received: 22 February 2026 Revised: 27 February 2026 Accepted: 11 April 2026 Available online: 15 June 2026 Keywords: Spheroidal graphite iron Non-destructive testing Ultrasonic velocity Property prediction ABSTRACT Introduction. Spheroidal graphite (SG) iron is widely used in engineering structures due to its high mechanical properties, which are largely determined by the degree of spheroidization (nodularity) of the graphite inclusions. Conventional metallographic evaluation of nodularity provides high accuracy but is a destructive and time-consuming procedure. Therefore, there is a need for a reliable non-destructive approach for rapid quality assessment of castings, especially in small-batch foundry production. The purpose of this work is to develop a methodological framework for predicting nodularity and mechanical properties of SG iron castings based on ultrasonic testing. Methods. Castings of three SG iron grades (SGI 400/12, 500/7, and 600/3) were manufactured according to a Taguchi L27 experimental design. The controlled process parameters were: pouring temperature (1,380–1,420 °C), carbon equivalent (4.0–4.6), and section thickness (5–15 mm). Ultrasonic testing was performed using a fl aw detector with a 4 MHz transducer to measure the longitudinal ultrasonic wave velocity in the samples. Nodularity was determined from the ultrasonic measurements using the instrument’s internal calibration and the corresponding velocity relationship. Ultimate tensile strength (UTS, σu) and Brinell hardness were determined by standard mechanical testing methods. Multiple linear regression models were developed relating the process parameters and ultrasonic velocity to nodularity, UTS (σu), and hardness. Results and Discussion. The developed models demonstrated high predictive capability, with coeffi cients of determination of R2 = 0.8955 for nodularity, R2 = 0.9954 for UTS (σ u), and R 2 = 0.8135 for hardness. Carbon equivalent was identifi ed as the most signifi cant parameter aff ecting all responses. Ultrasonic velocity showed a clear positive correlation with nodularity and mechanical properties. Validation using metallographic analysis confi rmed good agreement with ultrasonic predictions, with deviations within 2–3%. The study demonstrates that ultrasonic velocity can be eff ectively used to predict the microstructural and mechanical characteristics of SG iron. The developed regression models provide a simple and practical tool for non-destructive evaluation, ensuring rapid quality control in foundry production, especially for small-scale enterprises. For citation: Mhamane D., Bewoor A. Ultrasonic non-destructive property prediction framework for spheroidal graphite iron castings. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science, 2026, vol. 28, no. 2, pp. 179–195. DOI: 10.17212/1994-6309-2026-28.2-179-195. (In Russian). ______ * Corresponding author Mhamane Digvijay, Research Scholar Department of Mechanical Engineering, Zeal College of Engineering and Research, Narhe Pune, Savitribai Phule Pune University, 411041, Pune, Maharashtra, India Tel.: 0230 242 1300, e-mail: digvijay.ndt@gmail.com
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