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AssigneeThe Duriron Company, Inc.
InventorsRichard L. Helferich, William B. Shook
Estimating the term…
Granular compositions are disclosed for use in preparing hard, water and erosion-resistant, shapes such as foundry molds and cores, that are self-setting under ambient atmospheric conditions to allow such shapes to be stripped from patterns on which they are formed, such pattern stripping being possible immediately after forming in the case of foundry cores and the like, and within controllable pattern strip times as low as 60 seconds for foundry molds. The shapes may be used without baking and, in the case of foundry molds and cores, are ready for casting molten metal within as little as one hour. Molds and/or cores free of organic materials can be formed with the novel compositions, providing essentially carbon-free surfaces at the mold-metal interface, as well as being free of other deleterious elements such as sulfur, phosphorus and boron, thereby avoiding alloy composition alteration at the interface due to migration during casting. The refractory compositions of the invention incorporate unique aluminosilicate hydrogels of alkali metals as binders, are compatible in use with existing industrial foundry mold/core-forming equipment and procedures, and are eminently free of environmental (toxicity) problems in the foundry atmosphere.
Formed shapes of refractory material which are composed of a moldable mix that is self-setting without baking at ambient atmospheric conditions, said mix comprising at least 90% by weight of refractory granular particles, and an aluminosilicate hydrogel binder having a mole ratio of alumina to silica of about 0.33 to 2.0 for retaining said particles in said formed shapes, said binder consisting of an alkaline mixture of aqueous solutions containing, respectively, a water soluble source of silica and a water soluble source of alumina, said solutions being combined in said granular mix in proportion to produce said aluminosilicate hydrogel binder under said ambient atmospheric conditions, said aluminosilicate hydrogel producing in said formed shapes a minimum compressive strength of about 12 psi within 60-65 minutes at 50.degree. F. or within 10-12 minutes at 80.degree. F. ambient temperature, 50% humidity, and forming a substantially water-resistant rigid bond between the particles of the mix after molding said mix into said shapes.
A foundry mold for metal castings, said mold resulting from a mix comprising a composition which, when filled into a foundry mold flask and compacted against a pattern therein, acquires under ambient atmospheric conditions a sufficient set to be self-supporting upon removal of the mold or core from the pattern in a controllable time interval of from 60 to 90 seconds, said mix as initially prepared having a composition comprising a refractory granule base consisting essentially of zircon or silica sand or mixtures thereof in predominating proportion and minor amount of kaolin, and a binder solution constituting not more than about 6% by weight of the total mix, said binder solution forming an aluminosilicate gel resulting from reaction between aqueous solutions of an alkali metal silicate and an alkali metal aluminate, wherein the mole ratio of alumina to silica in the gel is from 0.33 to 2.0 and the total solids in said solutions is about 45% by weight.
A method of preparing a no-bake, self-setting granular mix containing a major proportion by weight of granular particles and a minor proportion by weight of a liquid binder, said method comprising
A method of preparing a totally inorganic foundry sand mix for making molds for metal castings, wherein said mix, when filled at ambient atmospheric conditions into a foundry flask or core box and compacted therein, acquires sufficient set within a controllable time as short as 60 to 90 seconds to be self-supporting upon removal of the mold from the flask or core box, said method comprising:
Dependencies are inferred from the claim text.