Abstract: Thin cast sheets having an excellent quality are obtained by continuous casting in which a semi-solidified metal slurry is fed from a continuous production device of the semi-solidified metal slurry through a discharge nozzle provided with means for heating the nozzle itself into a twin roll type continuous strip caster, at where the slurry is rapidly quenched and solidified to fine a structure and dispersion of precipitate.

Abstract: A semi-solidified metal composition having an excellent workability is continuously produced by pouring molten metal into an upper part of a cooling agitation mold, agitating it while cooling to produce a slurry of solid-liquid mixed phase containing non-dendritic primary solid particles dispersed therein and discharging out the slurry from a lower part of the cooling agitation mold. In this case, a ratio of shear strain rate at a solid-liquid interface to solidification rate of molten metal is adjusted to a value exceeding 8000 in the cooling agitation mold.

Abstract: Dispersion strengthened metal matrix composites are produced by stirring a mixed solid-liquid phase slurry as a dispersing medium under a reduced pressure, adding a dispersion strengthening material to the dispersing medium, and continuing the stirring under the reduced pressure till the dispersion strengthening material is uniformly dispersed in the dispersing medium.

Abstract: In a process and an apparatus for stably and continuously producing a solid-liquid metal mixture in which non-dendritic primary solid particles are dispersed into the remaining liquid matrix, molten metal is charged into a clearance between a wall member and a rotating agitator composed of a cylindrical drum having a horizontally rotational axis.

Abstract: Spray coating is performed utilizing a mixture of refractory material and a combustionable metal powder. The size of the particle of the metal in the mixture is selected so that the particle size is large enough to be treated safely and is small enough to be transported by means of a gas flow. As a carrier gas for carrying the mixture, a non-combustionable gas or fuel gas is used. A fuel gas and a combustion-assisting gas are discharged toward the section to be treated on the surface for directing a combustioning frame. The refractor material with the carrier gas is discharged into the frame established by the fuel gas and the combustion-assisting gas. The average size of the metal particle to be used in the spray coating is limited to be greater than 50 .mu.m. By enlarging the particle size of the metal, combustion of the metal particle becomes difficult. Combustion of such large particle size metal can be assisted by discharging the combustion-assisting gas together with the fuel gas.

Abstract: A method and an apparatus for manufacturing a hollow steel ingot are disclosed, which comprise coaxially arranging a cylindrical metallic core in a center of a mold and pouring molten steel into an annular casting space defined between the core and the mold to cool and solidify it. In this case, the core is constructed with a concentric double tube consisting of inner tube and outer tube and receives in its central portion a cooling gas tank provided at the outer peripheral surface with plural outlets opening toward the inner peripheral surface of the inner tube. An inert gas is flowed through an annular gap defined between the inner tube and the outer tube, while a cooling gas is blown toward the inner peripheral surface of the inner tube.