Tensile strength of BOF refractories determined by the diametral compression method

Diametral compression testing was conducted on magnesia-graphite refractory bricks containing different metallic additions. The diametral compression test, also known as the Brazilian or the Carneiro test, is an indirect tensile test which has been adapted for use on refractory materials. Specimens were cored from commercial MgO-C brick containing either aluminum, silicon, or magnesium metal additions. Specimens were heat treated to temperatures ranging between 600°C - 1500°C and tested at either elevated temperatures or at room temperature after heat treatment. After heat treatment and mechanical testing, several techniques were used to analyze the specimens including x-ray powder diffraction (XRD), reflected light (RL) and cathodoluminescence (CL) microscopy, and scanning electron microscopy (SEM). Results of a statistical study revealed that a three hour hold time during heat treatment and a sample size of eight specimens was sufficient to obtain reliable results. Diametral compression strength of all compositions was related to both microstructural development and apparent porosity--Abstract, page iv