Investigating the Effect of Auto-Focus and Auto-Threshold Algorithms in Advanced Nodularity Analysis of Austempered Ductile Iron Castings

B. Çetina, H. Kurtuldub, G. Durkayac, K. Davutc aFNSS Defense Systems Co. Inc., Engineering and Research Department, Ankara, Turkey bBaskent University, Department of Biomedical Engineering, Ankara, Turkey cAtılım University, Department of Metallurgical and Materials Engineering, Ankara, Turkey

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Austempered ductile iron castings have a wide range of application fields including defense and heavy-duty industries due to their promising mechanical properties. Austempered ductile iron castings could provide excellent combination of high strength, toughness, and wear resistance at the same time. Unlike other spheroidal ductile cast irons, austempered ductile iron castings need to be processed by a special austempering heat treatment which enables the verification of the conformity of the nodularity level after the casting operations. Previous studies have shown that wide area mappings for determining nodularity are crucial to eliminate the representativeness problems. In this sense, some precautions should be taken for the accuracy of results in large scale nodularity examination. In this study, the effect of auto-thresholding and auto-focusing algorithms on the advanced nodularity analysis is investigated. The results suggest that auto-thresholding and auto-focusing methods have significant contributions for determining average nodularity levels and average graphite sizes.

DOI:10.12693/APhysPolA.135.762 topics: auto-threshold, auto-focus, image analysis, nodularity analysis, austempered ductile iron castings