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The thermophysical properties (viscosity, density, and surface tension) of the secondary metallurgical slags with various CaO/Al2O3 ratios (0.56–1.99) and SiO2 (1–20 wt%) contents are investigated. The results show that the addition of SiO2 increases the viscosity of the cleanness and desulfurization slags (CaO/Al2O3 ratios ≥1). In slag with a higher Al2O3 content (CaO/Al2O3 < 1) and constant CaO content, the viscosity shows a first decreased and then increased phenomenon with the addition of SiO2. Moreover, the breakpoints of the viscosity are strongly lowered with the addition of SiO2. Both the density and surface tension of slags show a decreasing tendency with the SiO2 addition. Moreover, the single hot thermocouple technique method is applied to investigate the crystallization process of the slags, and the result shows that with high SiO2 contents, glassy layers are formed on the molten slags.

The combination of the austempered ductile iron mechanical properties strongly depend on the parameters used on the austempering cycle. On this study, the influence of austempering time and austenitizing temperature on the properties of a ductile iron were evaluated. A metallic bath of Zamak at 380°C was used as an austempering mean. A set of ductile iron blocks were austenitized at 900°C for 90 minutes and submitted to different austempering times in order to determine the best combination of microstructural and mechanical properties. After the definition of the time of austempering, the reduction of the austenitizing temperature was evaluated. The best combination of properties was obtained with austenitizing at 860°C and austempering during 60 minutes.

Precipitation of large Z-phase particles, Cr(V, Nb)N, replacing fine MX carbonitrides, Nb(C,N) or V(N,C), has recently been identified as a major cause for premature losses in long-term creep strength in high chromium martensitic steels for power plants applications. For developing a new heat-resistant steel with better creep performance for applications in modern power plants with service temperatures around 650 °C, martensitic steels with 9 wt.%Cr were studied to achieve a chemical composition without the presence of a reversion/formation of detrimental Z-phase from consumption of thermally stable carbonitrides. The alloy composition was design to control deleterious Z-phase precipitation based on extrapolation of conventional vanadium content. The modelling of the alloy content is relied on thermodynamic equilibrium calculations using MatCalc software and Schaeffler modified diagram to achieve a fully martensitic microstructure.