Foundry mixes containing sulfate and/or nitrate salts and their uses

Abstract

Disclosed is a foundry mix containing a sulfate and / or nitrate salt and its use to make foundry shapes by the warm-box, hot-box, no-bake, and cold-box process, the use of these foundry shapes to make metal castings, and the metal castings prepared by the process.

Description

Background technique [0001] Quartz sand (SiO 2 , quartz) is widely used as an aggregate in the metal foundry industry to produce molds and cores. The quartz sand is used for "green sand" (sand bonded with water and clay) and chemically bonded sand. A variety of inorganic and organic chemical binders are used, including phenolic urethanes, furans, epoxy-acrylates, and ester hardened phenolics. [0002] The binder is mixed with the sand and the mixture is compacted in the process equipment to form the desired mold and core form, the binder then hardens and bonds the sand grains together. The mold and core parts are then assembled into a mold assembly into which the metal is poured and the cavity is filled with the desired casting form. The heat from the liquid metal (especially in the case of ferrous alloys with a melting point above 1100°C) starts to break down the binder and heats the sand. As the quartz sand heats up, thermal expansion occurs. This expansion is relativel...

AI Technical Summary

Problems solved by technology

For example, iron oxide when used above about 2 wt% based on sand (BOS) can cause increased metal infiltration and reduced mold / core strength when used at higher levels

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