Main molds and cores with appropriate mold properties are indispensable for realizing high-quality castings. Various types of sand are used in sand molding, and the properties of the molding sand for obtaining good sand molds are determined and controlled. Molding CAE is a quick and convenient means of determining the molding conditions. However, practical molding CAE tools have not yet been developed because the sand molding phenomena occurring in the blow molding process are very complex. Moreover, there is a need to consider the differences in sand properties.

  In this study, blow molding experiments were conducted using several types of molding sands such as green molding sand with certain degree of compactability (CB Index), green sands with different sand particle components, and resin-coated sands (RCS) were prepared for the experiments. To obtain basic knowledge for the development of molding CAE, sand blowing phenomena were observed and the molding pressure waveform was analyzed. It was clarified that air has two types of effects in molding : transportation of sand particles and compaction of sand. The difference in sand particle movement between green sand and dry sand was also seen depending on the presence or absence of adhesive force. Based on these results, several governing equations for the development of molding CAE were proposed in this study.

  In order to achieve sustainable development goals (SDGs) in the casting process and become a decarbonized society by 2050, decarbonization in the manufacturing process, such as the utilization of converted biomass resources, should be promoted. Recently, recycled steel scraps that contain small amounts of carbon are increasingly being used as a cheap iron source. Since the total amount of carburizer used also increases in such applications, it is important to examine the characteristics of biomass, which is a sustainable carbon source and carbon-neutral, as a substitution for coal coke and to examine environmentally-friendly casting methods using biomass.

  Biocoke is a solid product for utilizing biomass effectively. It can be produced from herbaceous biomass. There are growing hopes that use of bamboo as a raw material can help realize domestic production of the carburizer. It has already been confirmed in the melting process using high-frequency induction melting furnace that biocoke has carburizing effects. However, the carburizing process and mechanism of biomass have not been examined.

  In this study, biocoke with different degrees of carbonization was carried out in the casting process to clarify the carburizing process. Graphitization degree was used for evaluating the carbon on the contact surface between the biocoke and molten metal. The effects of the carburizing process were reviewed based on carburizing effects and graphitization degree. The lower the degree of crystallinity of carbon in the biocoke, the faster the carbonization was carried out. It was found that carburizing occurred when the R-value, which indicates the degree of graphitization, reached around 0.8.

  Semi-solid high pressure die casting is known as a process capable of forming high quality products. JIS ADC12 aluminum alloy is widely used for high pressure die casting, but this alloy has a narrow semi-solid temperature range, making it difficult to apply the semi-solid process. In this study, the preparation of ADC12 aluminum alloy slurry by applying mechanical vibration was attempted. Mechanical vibration was applied during the solidification of ADC12 alloy from the liquid to semi-solid state, and the effects of parameters of mechanical vibration and pouring temperature on the morphology of slurry were been investigated.

  The application of mechanical vibration transformed the solid phase in the slurry from dendritic shape to fine spherical shape with increasing acceleration amplitude and velocity amplitude. As a result, slurry with solid particles dispersed in the liquid phase could be obtained. Moreover, it was found that high frequencies and displacement amplitudes above a certain value are required to obtain slurry with fine spherical solid particles. Fraction solid of slurry was affected by both the pouring temperature and vibration applied time, increasing with decreasing pouring temperature and increasing vibration time. Consequently, slurry with sufficiently fine spherical particles could be obtained by applying mechanical vibration with the frequency of 50 Hz and acceleration amplitude and velocity amplitude higher than 49.0 m/s2 and 0.19 m/s, respectively. In this way, the fraction solid of ADC12 alloy slurry could be controlled by controlling the pouring temperature and vibrations time.

  A seismic damper alloy with a composition of Fe-15Mn-10Cr-8Ni-4Si and excellent plastic fatigue properties has been developed. Since this material was designed for thermomechanical processing, its properties as a cast material have not been investigated. In this study, sand and permanent mold castings were fabricated using this alloy, and the effects of heat treatment on the material properties were investigated. Heat treatment at 1000℃ for up to 24 hours was applied to investigate changes in microstructure and tensile and fatigue properties. As a result, both sand mold and permanent mold castings showed good tensile properties. The permanent mold castings showed good plastic fatigue properties at the heat treatment times of 2 to 8 hours, and the number of fracture cycles at a strain amplitude of ± 1% exceeded 10,000 cycles. Transformation from γ-austenite to ε-martensite was observed during plastic deformation, suggesting that this transformation contributes to the good plastic fatigue properties. In the cast microstructure, Mn, Ni and Si were observed to segregate clearly in the inter-dendrite region, suggesting that the remaining of segregation to some extent also contributes to good fatigue properties.

  It is known that the water condensation zone generated during the green sand mold casting process is softer than the mold before pouring. In order to predict the deformations that occur during casting using FEM thermal stress analysis, it is necessary to take also into account the mechanical properties of the water condensation zone. This paper investigated the stress-strain relationship in the consolidation test of the water condensation zone. Consolidation tests were performed on the following two methods. One method used a test piece prepared with a fabricated device that generates water vapor and allows it to permeate the molded sand test piece. The other method used a test piece prepared by adding water equivalent to the water increase in the water condensation zone before mixing. During the generation of the water condensation zone, the sand skeleton does not move while air and water in the void within the test piece migrate. For this reason, the same water content and void ratio were set in the test pieces prepared by the two methods above by varying the squeezing pressure applied to form the test pieces. When permeating water vapor, the actual molding pressure (1.2 MPa) was applied in the preparation of the test piece. On the other hand, when adding water during mixing, a smaller pressure (0.17MPa) than the actual molding pressure was applied. The stress-strain curves obtained in the consolidation tests were compared to discuss which method is appropriate for clarifying the mechanical behavior of the water condensation zone. As a result, in the case of permeation of water vapor, the results did not follow the geotechnical engineering theory that granular materials yield at the maximum stress they are ever subjected to. In other words, yielding was not observed around the squeezing pressure (1.2MPa) in the preparation of the test pieces. On the other hand, when water was added before mixing, yielding was observed at the squeezing pressure (0.17MPa). However, the squeezing pressure 0.17MPa, which was used in order to standardize the void ratio of the test pieces, is unrelated to the formation of actual green sand mold, and yielding is not expected to occur at 0.17MPa in actual water condensation zones. Therefore, in order to obtain the required mechanical behavior of water condensation zone, test pieces must be prepared by allowing water vapor to permeate through them.

  This paper reports a recent trends in casting CAE investigated from published articles and themes to be worked on in the future. The investigations were carried on from April, 2018 to March, 2022. Some of the articles quoted in this paper were not mainly forced on related to CAE in some aspects. Not only the finalized papers but also some of the reports of JFS Meeting were quoted in this paper, they presents interesting ideas for practical application of casting CAE.