Provided are a powder for laser manufacturing which can be stably manufactured and from which a three-dimensional manufactured object ensuring a manufacturing accuracy can be obtained and a using method thereof. A powder for ceramic manufacturing for obtaining a manufactured object by repeatedly sintering or fusing and solidifying in sequence a powder in an irradiation portion with laser light, in which the powder includes a plurality of compositions, at least one composition of the compositions is an absorber that relatively strongly absorbs the laser light compared to other compositions, and at least a part of the absorber changes to a different composition that relatively weakly absorbs the laser light by irradiation with the laser light and a using method of a powder in which the powder is used.

Provided are a powder for laser manufacturing which can be stably manufactured and from which a three-dimensional manufactured object ensuring a manufacturing accuracy can be obtained and a using method thereof. A powder for ceramic manufacturing for obtaining a manufactured object by repeatedly sintering or fusing and solidifying in sequence a powder in an irradiation portion with laser light, in which the powder includes a plurality of compositions, at least one composition of the compositions is an absorber that relatively strongly absorbs the laser light compared to other compositions, and at least a part of the absorber changes to a different composition that relatively weakly absorbs the laser light by irradiation with the laser light and a using method of a powder in which the powder is used.

Provided is a refractory product which is not impregnated with pitch or the like, wherein it has higher corrosion-erosion resistance and thermal shock resistance as compared to a refractory product subjected to pitch or the like-impregnation treatment. The refractory product which is not impregnated with tar or pitch is characterized in that, in terms of values of physical properties of a sample of the refractory product as measured after heat-treating the sample in a non-oxidizing atmosphere at 1200° C.: an apparent porosity is 7% or less; a total void volume of pores having a pore diameter of 1 μm or less is 80% or more of an integrated void volume of pores of the entire sample of the refractory product; and a gas permeability is 50×10.sup.−17 m.sup.2 or less.

Provided is a refractory product which is not impregnated with pitch or the like, wherein it has higher corrosion-erosion resistance and thermal shock resistance as compared to a refractory product subjected to pitch or the like-impregnation treatment. The refractory product which is not impregnated with tar or pitch is characterized in that, in terms of values of physical properties of a sample of the refractory product as measured after heat-treating the sample in a non-oxidizing atmosphere at 1200° C.: an apparent porosity is 7% or less; a total void volume of pores having a pore diameter of 1 μm or less is 80% or more of an integrated void volume of pores of the entire sample of the refractory product; and a gas permeability is 50×10.sup.−17 m.sup.2 or less.

A porous refractory cast material contains a closed refractory aggregate fraction having a minimum particle size and a maximum particle size; the ratio of maximum particle size to minimum particle size is 10:1 or less. This closed refractory aggregate fraction comprises all of the porous refractory cast material having a particle diameter greater than 0.1 mm. The porous refractory cast material also contains a binder phase containing refractory selected from calcium aluminate cement, alumina phosphate, hydratable alumina, colloidal silica and combinations thereof. Also disclosed is a metallurgical vessel with an interior lining incorporating the porous refractory cast material.

A porous refractory cast material contains a closed refractory aggregate fraction having a minimum particle size and a maximum particle size; the ratio of maximum particle size to minimum particle size is 10:1 or less. This closed refractory aggregate fraction comprises all of the porous refractory cast material having a particle diameter greater than 0.1 mm. The porous refractory cast material also contains a binder phase containing refractory selected from calcium aluminate cement, alumina phosphate, hydratable alumina, colloidal silica and combinations thereof. Also disclosed is a metallurgical vessel with an interior lining incorporating the porous refractory cast material.

A porous refractory cast material contains a closed refractory aggregate fraction having a minimum particle size and a maximum particle size; the ratio of maximum particle size to minimum particle size is 10:1 or less. This closed refractory aggregate fraction comprises all of the porous refractory cast material having a particle diameter greater than 0.1 mm. The porous refractory cast material also contains a binder phase containing refractory selected from calcium aluminate cement, alumina phosphate, hydratable alumina, colloidal silica and combinations thereof. Also disclosed is a metallurgical vessel with an interior lining incorporating the porous refractory cast material.

A porous refractory cast material contains a closed refractory aggregate fraction having a minimum particle size and a maximum particle size; the ratio of maximum particle size to minimum particle size is 10:1 or less. This closed refractory aggregate fraction comprises all of the porous refractory cast material having a particle diameter greater than 0.1 mm. The porous refractory cast material also contains a binder phase containing refractory selected from calcium aluminate cement, alumina phosphate, hydratable alumina, colloidal silica and combinations thereof. Also disclosed is a metallurgical vessel with an interior lining incorporating the porous refractory cast material.

Heat treated alumina zirconia abrasive grains based on Al.sub.2O.sub.3 and ZrO.sub.2 may be fused in an electric arc furnace, and may have a weight content of: Al.sub.2O.sub.3 between 52% and 62% by weight; ZrO.sub.2 and HfO.sub.2 between 35% and 45% by weight, with at least 6% by weight based on the total weight content of ZrO.sub.2 being present in the tetragonal and/or cubic high temperature modifications of ZrO.sub.2; Si-compounds between 0.2% and 0.7% by weight expressed as SiO.sub.2; carbon between 0.03% and 0.5% by weight; additives between 0.5% and 10% by weight; and raw-material-based impurities of less than 3% by weight. The heat treated alumina zirconia abrasive grains may be heat treated in air between 350° C. and 700° C. for a time period of one to six hours using a rotary kiln.

A refractory material contains: 40 mass % or more of MgO; 4 to 30 mass % of a free carbon component; and one or more of B.sub.2O.sub.3, P.sub.2O.sub.5, SiO.sub.2 and TiO.sub.2, in a total amount of 0.3 to 3 mass %, with the remainder being at least one other type of additional refractory component. A void layer exists in an interface between a carbon-containing matrix microstructure residing at least on opposite sides of a maximum-size one of a plurality of MgO-containing particles in the refractory material, and the maximum-size MgO-containing particle. A sum of respective thicknesses of the void layer at two positions on the opposite sides is 0.2 to 3.0% of a ratio with respect to particle size of the maximum-size MgO-containing particle. An inorganic compound of MgO and the one or more of B.sub.2O.sub.3, P.sub.2O.sub.5, SiO.sub.2 and TiO.sub.2 exists entirety or partially in a surface of each of the MgO-containing particles.