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Inert Gas Stirring for Induction Furnaces

Jan. 21, 2011
A patent-pending purging nozzle diffuses inert gas into the molten metal bath of a coreless furnace, to promote chemical homogenization and metal cleanliness.
Inert gas is diffused into the molten bath of a coreless furnace, to promote chemical homogenization and metal cleanliness.

Allied Mineral Products Inc. manufactures monolithic refractories, specializing in custom lining designs for optimum thermal and mechanical characteristics, refractory technology, and sales and service support. In its commitment to finding solutions for molten metal applications, Allied introduced Minro Stir Pro Nozzles as part of a package for induction furnaces.

Minro Stir Pro Nozzles are used to diffuse inert gas into the molten metal bath of a coreless furnace. This patent-pending purging nozzle promotes chemical homogenization and cleanliness in the metal by floating inclusions to the slag layer of the bath. Allied’s DRI-VIBE® refractory technology allows inert gas to permeate the floor refractory while it is diffused through the Minro Stir Pro Nozzles.

These nozzles bring the advantages of inert-gas stirring of molten metals to coreless induction furnaces for ferrous and nonferrous foundries, including: homogenization of alloys and temperature; flotation of nonmetallic inclusions (oxides, sulfides, and nitrides) for cleaner, better quality metal; and aiding the removal of dissolved gas from the metal. The process reduces oxidation in the molten metal bath in air-melt coreless furnaces by creating a “blanket” of inert gas on top of the bath during bubbling. Among the practical advantages that result are greater metal density and a reduction in casting scrap. Operators may accomplish multiple campaigns with every nozzle, and the finished castings require less grinding and cutoff after unmolding.

Minro Stir Pro Nozzles are available in a range of sizes and types to fit different coreless furnaces, including the original stainless steel design for use over multiple campaigns; a new, all-ceramic design that’s useful for high-temperature applications or where a magnetic coupling may be present; and a new model with a small cross-section for use in furnaces with capacities of 500 lb or less.

Allied Minerals offers kits to ensure optimal performance from Minro Stir Pro Nozzles, and to help ensure accurate and consistent delivery of inert gas to the furnace. The Premium Protocol Station includes a flow meter and two pressure regulator gauges. One monitors tank pressure and the other exit pressure. This station can be attached directly to the inert gas tank. Delivery hoses are available in 50-ft (15.2- m) or 25-ft. (7.62-m) designs.

For more information, contact Allied Mineral Products at 614-876-0244, or visit