Zn-Al and Zn-Al-Cu-Mg alloys containing Al 3.6 to 27.0%, Cu 0.7 to 2.3% and Mg 0.06 to 0.4% were tested. Microsegregation in the dendritic β-phase is promoted and consequently the cored structure in which Al is extremely condensed at the center is formed when the Al content increases. When dendritic β-phase transforms to α+β´ eutectoid structure, it is always surrounded by granular β´ crystals. Nonequilibrium eutectic phases disappear by solution treatment. Homogenizing of the microsegregation zone delays as Al content increases. Cu addition results in the precipitation of ε-phases and hardens the α-phases in Zn-Al alloys. A large amount of Zn-Al-Cu-Mg particles precipitate in the alloys containing an excess amount of Mg. These particles are held at the grain boundary by solution treatment. The hardness of Zn-Al alloys is remarkably raised when increasing amount of Mg is added.

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  Liquid photopolymer is cured by ultraviolet ray passed through a photographic film. Taper of the pattern is generally proper for casting, but that at the sharp edge is inadequate due to the shortage of ultraviolet ray. Some treatments were discussed and the precise behavior of liquid photopolymer cured by ultraviolet ray was investigated. Photopolymer patterns for casting are highly accurate and can be manufactured easily and quickly, although there is a height restriction. Photopolymer patterns will be applied in future foundries.

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  As-cast and heat treated Cr cast irons containing C 1.7 to 3.8% and Cr 3 to 26% were prepared in which such additives as V 5 to 8%, Ni 4 to 6%, Mo 1 to 2% and Ti 0.2% had been introduced. Sand erosion tests were carried out under corrosive wear condition with flattery silica sand of 90 mesh 40 vol.% and water 60 vol.%. Wear of the cast irons proceeds from interphase corrosion between matrix and carbides and is followed by abrasive and corrosive wear of matrix. Weight loss of the cast irons decreases with an increase in Cr content in the matrix. The sand erosion resistance of lower Cr irons is improved by quench and temper hardening. V, Ni, Mo and Ti in the irons improve the wear resistance 1.69%C-12.2%Cr-4.77%V-0.92%Mo-0.2%Ti and 2.29%C-12.4%Cr-8.46%V-1.00%Mo-0.2%Ti cast irons containing granular eutectic vanadium carbides and fine granular secondary carbides are particularly superior in terms of sand erosion resistance even under more corrosive wear condition with flattery silica sand 40 vol.% plus water 54 vol.% and sea water 6 vol.%.

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  A method for dispersing solid particles such as alumina, carborundum and graphite in molten Al and Cu alloys by gas atomizing technique was studied. The conditions of dispersing particles and their distribution in the solidified alloys were investigated. Particles over the size of 30μm are successfully dispersed and retained in the alloys solidified at moderately rapid rates, but are rejected during remelting. This tendency is more remarkable in Cu alloys than Al alloys. The dispersion of particles in the alloys are improved by the addition of 2%Ca in Al alloys and 0.5%Ti in Cu alloys.

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  More than one thousand sets of data on mechanical properties of spheroidal graphite cast irons offered from several foundries were analyzed by the application of “Streufeldanalysis” developed in West Germany. The spheroidal graphite cast irons produced in West Germany have slightly higher proof stress than those produced in Japan when their tensile strength is at the same level. The case is reversed for elongation. This appears to be due to the difference between phosphorus contents in the two countries. The specification of proof stress of spheroidal graphite cast iron in Japan Industrial Standard seems to be specified so high to be cleared easily especially at the high tension level. It is recommended from the standpoint of producers that the specified proof stress of spheroidal graphite cast irons in JIS should be reduced in its next revision taking account of this work. It is also recommended that the specification of elongation in JIS should be reconsidered.

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  The self hardening molding process which uses polyvinyl alcohol (P. V. A.), boron compound and cement as binders was investigated. Cement plays an important role in improving mold strength and controlling bench life of mold sand. Didiol type reaction takes place between P. V. A. and boron compound. This reaction also results in improving mold strength. The mold produced by this process has sufficient strength and endures heat and pressure of molten metal. Gray cast iron castings weighing 50 to 100kg per piece were cast using these molds. The process yields precise castings free from defects. The mold has preferable collapsibility and has great utility for casting.

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