Experimental and Modeling Study of Deformability of Glassy CaO-(MnO)-Al2O3-SiO2 Inclusions

The occurrence of non-deformable, non-metallic inclusions is the dominant reason for failure of wire during drawing and degrades service life for some steel grades, e.g., tire cord steel. To investigate the deformability of glassy inclusions in CaO-Al2O3-SiO2 and MnO-Al2O3-SiO2 systems, experimental and numerical methods were used. Young’s modulus values of some glasses based on the CaO-Al2O3-SiO2 and MnO-Al2O3-SiO2 systems, which correspond to typical inclusions in tire cord steel, were measured with resonant ultrasound spectroscopy. The effect of basicity, defined as the ratio of mass percentage of CaO to SiO2, on Young’s modulus and Poisson’s ratio were investigated. The Young’s moduli of glasses are enhanced with increasing basicity, which could be attributed to the high field strength of calcium ions. The Poisson’s ratios of glasses also show an increase tendency with increasing basicity, which could be due to the loss of rigidity of network with introduction of calcium ions. The equations in the literature for Young’s modulus calculation were evaluated based on the present and literature data. Appen’s equation is modified by re-fitting the present and literature data to give accurate estimation of Young’s modulus with the mean deviation of 2%. The iso-Young’s modulus diagrams for CaO-Al2O3-SiO2 systems were constructed. It is proposed that the iso-Young’s modulus diagram could be combined with liquid area in CaO-Al2O3-SiO2 ternary phase diagram to optimize the inclusion composition during both hot rolling and cold drawing.