THERMO-MECHANICAL CHARACTERISATION OF MAGNESIA-CARBON REFRACTORIES BY MEANS OF WEDGE SPLITTING TEST UNDER CONTROLLED ATMOSPHERE AT HIGH-TEMPERATURE

Due to their intrinsic properties and performance, Magnesia-Carbon refractories (MgO-C) are nowadays a key component of steel production. Especially the carbon bond/fraction accounts for their outstanding resistance to corrosion and thermal stress. However, this carbon fraction is also responsible for difficulties during testing the materials properties at typical service temperature (up to 1750 degrees C), which are nonetheless relevant and necessary for a sound performance evaluation. In presence of oxygen and at elevated temperature, the carbon present in the matrix burns off, leaving behind a MgO skeleton with only minimal ceramic bond which is not representative for the complete MgO-C material. With a new testing device that operates under controlled atmosphere, wedge splitting tests according to Tschegg were successfully carried out to measure the fracture mechanical characteristics (nominal tensile strength and the specific fracture energy) of MgO-C refractories at high temperature. The testing system is introduced and results from hight-emperature wedge splitting tests of MgO-C specimens are shown and discussed.