Integrated Computational Materials, Process and Product Engineering – IC-MPPE 2022

A carbon-containing magnesia refractory product (MgO−C) as it is applied in steel ladles of the secondary steel metallurgy was investigated for the Mode I fracture behaviour. Usually, it is determined with the wedge splitting test to quantify the thermal shock behaviour, the materials' brittleness or to gain input parameters for thermomechanical Finite Element (FE) simulations. For high temperature testing of carbon-containing refractories, a gas purging, for example with argon, is required to avoid carbon oxidation in the sample. Laser speckle extensometers measure the displacement in a contactless manner. Based on the results obtained from the tests, fracture mechanical parameters such as the specific fracture energy and the nominal notch tensile strength were calculated. An inverse FE simulation yielded tensile strength, the total specific fracture energy, and the strain-softening behaviour. As refractories often show significant creep rates at application temperatures, the creep behaviour was also considered in the inverse evaluations. Finally, the contribution of creep to the determined fracture energy was quantified.