Enhancing structural integrity of refractories during manufacturing through integration of UPV and acoustic nonlinearity measurements

This paper addresses the critical need for robust quality assurance in commercial refractories, emphasizing the role of Ultrasonic Pulse Velocity (UPV) testing in assessing material integrity. Traditionally, UPV testing has become a standard practice for evaluating refractory, ceramic, and concrete materials after production. However, this study introduces an innovative approach by advocating the integration of UPV tests at an intermediate stage prior to temperature curing. The primary objective is to predict the performance of refractory samples under compressive loading, examine intrinsic damages, and analyse ultrasonic characteristics in both time and frequency domains. Experimental investigations introduce damages, including artificial voids simulating various defect types, both before and during heat treatment. Analysis of UPV, Root Mean Squared (RMS) values of frequency spectra, and the acoustic nonlinearity parameter (ANP) reveals substantial differences between healthy and damaged regions. The mean UPV and RMS values consistently decrease in damaged regions, indicating sensitivity to defect severity. The ANP is sensitive to damage size, especially with higher frequency transducers detecting subtle changes more effectively. These findings emphasise the potential for proactive testing at an intermediate stage in the manufacturing process, enhancing the structural integrity and overall quality of refractory materials.