Abstract: Partially devitrified silica cores with exceptional high temperature strength are disclosed for foundry use in sand casting of ferrous alloys. Precision cored holes of small size and long length, which heretofore could not be cast accurately or had to be machined because of limitations in existing core technology, are formed using accurately machined extruded porous silica cores fired to eliminate combustibles and partially devitrified (e.g., 15 to 30%) to develop a strong crystalline phase bond that resists viscous flow at a temperature of 1500.degree. C. and to increase the refractoriness of the vitreous silica grains, whereby the permeability and thermal shock resistance are such that the core can be heated very rapidly by molten steel to above 1500.degree. C. without spalling, cracking, sagging, breaking, or loss of integrity and without gas holes, scabs, fissures or other serious casting defects.

Abstract: Partially devitrified silica cores with exceptional high temperature strength are disclosed for foundry use in sand casting of ferrous alloys. Precision cored holes of small size and long length, which heretofore could not be cast accurately or had to be machined because of limitations in existing core technology, are formed using accurately machined extruded porous silica cores fired to eliminate combustibles and partially devitrified (e.g., 15 to 30%) to develop a strong crystalline phase bond that resists viscous flow at a temperature of 1500.degree. C. and to increase the refractoriness of the vitreous silica grains, whereby the permeability and thermal shock resistance are such that the core can be heated very rapidly by molten steel to above 1500.degree. C. without spalling, cracking, sagging, breaking, or loss of integrity and without gas holes, scabs, fissures or other serious casting defects.

Abstract: An improved dust collection and illumination system is utilized in association with a plurality of work areas at which dust particles are formed during work operations. A combination lamp and dust collector is mounted on a workbench at each of the work areas and is connected with an exhaust manifold which conducts a flow of air and dust particles from the work areas to the intake of a blower. Each combination lamp and dust collector includes a reflector which is connected with the manifold by a flexible conduit and a light bulb which is mounted in the reflector and is effective to illuminate a work surface. Air and dust particles are drawn into the reflector, around the light bulb to cool the bulb, and through the flexible conduit and manifold to the blower. A linkage is utilized to support the reflector above the work surface. This linkage is adjustable to enable the position of the reflector to be changed.

Abstract: A porous high-silica core is disclosed for use in directional solidification casting processes having exceptional thermal stability at temperatures above 1650.degree. C. and containing mineralizers which promote the formation of cristobalite. The cores may be made by mixing at least 75 parts of essentially pure fused silica particles with 1 to 25 parts of activating particles containing a mineralizer, such as an alkali metal or alkaline earth metal compound, may be fired at a temperature of 1000.degree. to 1300.degree. C. until they contain 35 percent or more of cristobalite and may then be cooled to room temperature. They may thereafter be incorporated in a shell mold in accordance with the "lost-wax" process and preheated with the shell mold at a temperature of 1300.degree. to 1600.degree. C. to provide a cristobalite content of 60 to 85 percent or more within a short period of time, such as 10 to 30 minutes, and before a molten superalloy is allowed to flow into the mold.

Abstract: A process is disclosed for making vitreous silica crucibles of exceptional high quality for use in the growing of a silicon crystal from molten silicon. The crucibles are formed from fine particles of high purity fused silica by slip casting or other suitable process, are dried and fired to provide a rigid porous body, and are thereafter sintered to a high density, preferably to the transparent state. The invention solves the problem of spalling, blistering and cracking during crystal growing and the resulting contamination of the molten silicon, which has long plagued the industry, by eliminating water from the fused silica particles before the porous body is sintered to the transparent state. Said body is thoroughly dried in a vacuum furnace at a high temperature and at a sub-atmospheric pressure low enough to remove the chemically bound water which cannot be removed by heat alone.

Abstract: Apparatus is disclosed for automated mass production of precision transparent silica glass products in accordance with a unique process in which slip-cast fused silica articles are rapidly heated and sintered in a vacuum or in a helium or hydrogen atmosphere at high temperatures, such as 2950.degree. to 3150.degree.F. A heated graphite susceptor shaped to conform to the outer surface of the fused silica article is automatically moved between a cooling zone and an induction furnace chamber which is opened momentarily to admit the article. The furnace and the graphite susceptor are designed to cause the trapped gases in the article to move radially outwardly and to effect rapid heating so as to avoid substantial devitrification during sintering.