A Novel Method to Measure Cleanliness in Steel Using Ultrasonic C-Scan Image Analysis

The traditional method of measuring the cleanliness level of steel is to measure its total oxygen (TO), which does not provide information about the size, location, and distribution of more harmful macroinclusions. The present article highlights a novel method for cleanliness assessment in steel samples using ultrasonic C-scan image analysis. The method provides quick and large volume inspection and ability to catch macroinclusions that possess difficulty during further processing of the thin gage steel products, particularly for auto grades such as interstitial-free (IF) steel. This method deals with a multiscan, immersion ultrasonic system using high-frequency focused beam and image analysis software. A good correlation was found between ultrasonic parameter counts and TO in steel samples taken from tundish during the continuous casting of slab. The ultrasonic counts were also found to be correlated with some steelmaking parameters.