REFRACTORY WEAR AND LINING PROFILE DETERMINATION IN OPERATING ELECTRIC FURNACES USING STRESS WAVE NON-DESTRUCTIVE TESTING (NDT)

Effective maintenance practices improve safety of the operating unit, enhance safety during maintenance periods, increase operating up-time, and decrease overall maintenance costs. This paper outlines the application of Hatch’s furnace condition monitoring program with emphasis on Acousto Ultrasonic-Echo (AU-E), a manually operated, non-destructive testing and evaluation (NDT & E) measurement system that determines the thickness and physical properties of installed refractory components. The system identifies refractory wear profiles and determines positions of cracking, metal infiltrations, and other anomalies within linings. Utilization of the AU-E system, both after rebuild and at regular intervals, provides data to determine the extent of refractory deterioration. Additionally, data analysis algorithms identify areas of hydration based on AU-E results, which are crucial for scheduling shutdowns and assessing repair needs. This article discusses the AU-E technique's principles and applications for assessing the conditions of hearth, sidewalls, tapholes, and roofs of refractories, and presents two case studies demonstrating its application in an electric furnace and a flash furnace.