Wear progress monitoring in torpedo ladles in steel industry

Abstract

Torpedo ladles are necessary transport carriages in steel production to move the molten crude iron from the blast furnace to the steel refining plant. This requires the ladles to be high temperature resistant and insulate well to preserve the temperature and hold the risk of solidification at bay. Therefore, the involved refractories lining the inside of the torpedo ladles are chosen mostly according to their thermal properties, although wear resistance of the materials to the transported good is also of major importance. In this work we combined investigations of the thermal behaviour with wear monitoring of the lining of a torpedo ladle to establish a methodology for investigating the wear evolution over the whole lifetime of this large-scale high temperature machinery.

The core of the investigation were detailed 3D measurements of the ladle's cavity and thereby quantitative information of the wear progress at different time intervals during the lifecycle of the ladles. The measurements allowed for a separation of different wear zones according to severity, namely the “splash zone” where the melt directly hits the ladle, the “melt zone” where during transport always liquid melt is present, and the “slag zone”, where the slag floats on the melt causing severe wear loss. Thermal imaging and localised long-term temperature measurements allowed for a study of the thermal consequences entailed by the wear onset. Thereby a wear assessment based on temperature measurements from the outside of the ladle was made possible. Additional “classical” damage analysis of the worn refractories completes the investigation to identify the wear mechanisms leading to the substantial wear losses observed.