Measurement of Thermal Conductivity of Magnesia Brick with Straight Brick Specimens by Hot Wire Method

Abstract

As a result of a revision of the JIS system, the application of the hot wire method for determining thermal conductivity has been expanded from heat-insulating bricks to refractories with higher heat conductivity. In this regard, focusing on magnesia bricks, which are used in the safety lining of converters and a wide variety of other applications, the authors studied the possibility of applying the non-stationary hot wire method in the determination of thermal conductivity up to the high-temperature range by using straight brick specimens. To perform measurements on magnesia bricks, whose thermal conductivity is higher than that of heat-insulating bricks, a set of measurement equipment including a high-capacity electric furnace was constructed, and as a result, it was possible to confirm the linear relationship between the increase in temperature θ of the hot wire and the logarithm of time logt by using straight brick specimens. It is possible to determine the thermal conductivity accurately by identifying the critical point where the θ−logt relationship ceases to be linear and calculating the thermal conductivity of the target material on the basis of the linear relationship.