Among the family of stainless steels, cast austenitic stainless steels (CASSs) are preferably used due to their high mechanical properties and corrosion resistance. These steels owe their properties to their microstructural features consisting of an austenitic matrix and skeletal or lathy type δ-ferrite depending on the cooling rate. In this study, the solidification behavior of CASSs (304L and 316L grades) was studied using ThermoCalc software in order to determine the solidification sequence and final microstructure during cooling. Theoretical findings were supported by the microstructural examinations. For the mechanical characterization, not only hardness measurements but also tribological studies were carried out under dry sliding conditions and worn surfaces were examined by microscopy and 3D profilometric analysis. Results were discussed according to the type and amount of microstructural features.
It is important to characterize boron containing minerals because of their uses in a wide range of applications. The purpose of this study is to characterize Espey colemanite by minerological, petrographical and thermal means and to investigate the variation of its physical properties with temperature (up to 600 °C). Colemanite, having a non-porous crystalline structure, was found to consist of 35.8% B2O3 and 30.5% SiO2. The thermal decomposition of colemanite occurred within the temperature range of 300–600 °C. It was found that calcination, a thermal treatment method, influenced the physical properties of colemanite. The highest surface area, 131.9 m2/g, was obtained at 500 °C. The physical properties were found to have high statistical relation.
The purpose of this study is to investigate the use of İzmir (Menderes-Cumaovası) expanded perlite as a construction raw material by determining its characteristic properties, as well as its physical properties at different temperatures (up to 600°C). The perlites, having glassy, porous structure, were found to contain 70.68% SiO2 and 13.04% Al2O3. The physical properties of the perlites changed with temperature. The highest surface area, 524 m2/g, was obtained at 400°C. The physical properties were found to have high statistical relation. It was concluded that expanded perlite aggregates could be used as a construction raw material.
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