Statistical Analyses of Comparative Methods of Ultrasonic Velocity, Digital Image Analysis Metallography and Plain Cup Thermal Analysis for Front-End Nodularity Determination of Final (Treated & Inoculated) Ductile Iron

Abstract This paper reports on the results of a couple ‘end-of-week’ ductile iron fade campaigns which utilized sample sets of both water-quenched and mold-cooled pitch-and-catch ultrasonic velocity coupons along with plain thermal analysis (TA) cups of both 'round' and 'square' cavities. Those physical samples were then used to compare the methods of ultrasonic velocity and digital image analysis metallography, as both derived from the ultrasonic velocity coupons, as well as the eutectic recalescence of the plain TA cups, as derived from the real-time molten iron sampling, for the ‘front-end’ nodularity determination of final (treated and inoculated) ductile iron. Each of the numerous sample sets also included spectrometer chemistry slugs, and each discrete sample set was cast approximately every five minutes over several hours during each end-of-week fade campaign out of a pressure-pour furnace. Both GR&R and correlativity analyses were then conducted from amongst all the acquired samples and resultant test data.