Measurements of Some Thermal Properties of Steel-Refractory Systems and Heat Losses from Steelmaking Furnaces

Experimental procedures have been developed to measure heat losses and temperature in a laboratory scale, high temperature furnace under different conditions and thereby, to estimate various thermal properties of steel-refractory system such as emissivity, thermal conductivity and thermal contact resistance between refractory and steel plates etc. To these ends, a large number of experiments were carried out in an in-house designed resistance furnace with the help of pyrometers, contact thermocouples and heat flux transducer etc. Prior to detailed experimental work, calibrations of different measuring devices viz. thermocouple, pyrometer, heat flux transducers was carried out and measurements evaluated against available data bases, well established theoretical frameworks as well as against a computational procedure developed in-house. It is shown that while thermo-physical properties tend to depend on specific composition of material chosen, present estimates are not largely different from values reported for similar material in the literature. Thermal properties of the materials and contact resistances thus determined were finally embodied in a mathematical model, to calculate (i) transient thermal profile in a steel ladle lining during pre-heating operation and (ii) in situ wear (or thinning) of refractory lining in an industrial scale steelmaking furnace