The yield in the iron ore sintering process is managed in daily operations as an important indicator of manufacturing costs and CO₂ emissions. Currently, general yield operation actions are “feedback” based on yield results, and do not prevent yield loss. In order to prevent yield decline by “feed-forward” type action targeting yield changes, yield prediction based on operating conditions is essential. In this study, we assumed that yield is synonymous with the strength of the discharged sintered cake, and attempted to apply the porous material strength estimation formula to the sintered cake. The sintered cake was divided into a cake pore part lost by crushing and a sintered ore part as a matrix portion containing pores that remain after crushing, and the formulation of cake porosity and sintered ore strength was studied. Using the amount of melt (melting ratio) generated in liquid-phase sintering and its penetration length into the ore as key factors, the estimation formulas for cake porosity and sintered ore strength were built. In addition, experiments using diffusion pairs were carried out to verify the hypothesis regarding the penetration distance. A pot test were carried out to verify the constructed model, and confirmed a good correlation between the calculated yield by bed temperature measured and the blending components, and the actual measured yield.

Material applied in low-temperature liquefied gas storage tanks is required to have sufficient toughness. In recent years, high Mn austenitic steel has attracted attention for use in this application. In this study, the basic deformation characteristics and toughness of high Mn steel containing about 25% Mn were compared with those of 9% Ni steel in order to investigate the applicability of high Mn steel to LNG tanks. The high Mn steel showed larger uniform elongation than the 9% Ni steel due to higher strain-hardening, but elongation after the maximum load was significantly smaller. The plastic flow stress of the high Mn steel increased with decreasing temperature and showed temperature dependence similar to that of 0.2% proof stress in the 9% Ni steel. The Charpy absorbed energy of the high Mn steel was about half that of the 9% Ni steel, with an average value of 86 J at 77 K. Cleavage fracture surfaces were not observed in the fracture surfaces obtained at any temperature, indicating the micro-void coalescence type of fracture. The characteristics of ductile damage in the high Mn steel were discussed based on observation of micro-voids.