Joining of Niresist cast irons containing 18 and 32wt%Ni with reaction-bonded SiC (R.B.-SiC) was attempted. Molten Niresist cast iron was joined with R.B.-SiC containing 10, 20 and 30wt% free silicon at 1,250, 1,300 and 1,350°C for 1.5, 10 and 30 min. Two reaction layers in which carbon precipitates in the diffusion controlled layer I and such intermetallic compounds as FeSi etc. are produced in the layer II are formed at the well wet interface. Estimated apparent activation energies for forming the layer I in 18 and 32wt%Ni Niresist cast irons are 261 and 305kJ/mol, respectively. Free silicon of R.B.-SiC plays an important role in this joining reaction. Cracking is yet a problem awaiting solution.

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  Cast aluminum bronzes containing 8.5 to 12.9%Al, 3.9 to 4.3%Fe, 3.9 to 4.8%Ni and 1.0 to 1.2%Mn were heated at 1,020°C and cooled at various rates. Some of them were followed by tempering at 600 to 700°C. Aggresive dealloying corrosion occurs in the bronzes of β'and/or γ₂ phases. The solute element distribution in the dealloyed region changes corresponding to the microstructure. The resistance to dealloying corrosion of the bronzes containing Al above 9.5% is improved by tempering, but is inferior to that of the bronzes containing Al below 9.5%. The saturation magnetization increases by precipitation of Fe-rich κ₂ and/or κ₄ phases. The corrosion of aluminum bronzes is may be estimative by measuring magnetic properties.

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  A Ni-base single crystal alloy, Alloy 454, was melted in the ceramic shell mold at 1540°C and held for 2h under reducing pressure 2x10^-4 Torr. Reaction layers which consist of Al₂O₃ for the most part 2.3 to 4μm and 7.3 to 16μm in thickness are found on the surface of solidified alloys held for 1 and 2h, respectively. The alloys are contaminated with 0.013 to 0.035% of Si. These facts are attributed to the reaction of free silica remaining in the mold without forming mullite to aluminum in the molten alloy. The reaction is so moderate that the proposed mold composition is applicable for single crystal casting.

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  A new grain refining casting process “Kawasaki Microcast Process” for producing high strength and low cost turbine disks has been developed. This process ensures extremely grain refined microstructure as fine as ASTM No. 3 to 6 and higher tensile strength than conventional casting processes. Even high alloyed superalloys which are usually difficult to forge can be forged. IN792+Hf is the most preferable alloy for this process in all alloys tested. If cast by this process, IN792+Hf has tensile properties as high as and rupture properties higher than those of power forged disk materials.

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  Four types of spheroidal graphite cast irons in which the pearlite ratio had been controlled from 0 to 94% were tested at −150 to 20°C. Fracture toughness J_IC at 20°C lowers as the pearlite ratio increases. The lowering rate at the pearlite ratio 0 to 50% is smaller than that at 50 to 100% . All specimens show a transition behavior as temperature lowers that J_IC greatly decreases by transition of fracture mode from ductile to brittle. The lowest temperature of the upper shelf region and the transition temperature in the relation between J_IC and temperature rise as the pearlite ratio increases. The fractography well corresponds to these facts.

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