CS240820B1 - Foundry Forming and Core Molding - Google Patents

Abstract

Foundry molding and core mixture containing as a binder an alkali silicate solution and optionally additives, for example carbon black powder. The mixture further contains from 0.05 to 1.00 parts by weight of an ester of phosphoric acid and an alcohol of the general formula (RO)^PO, where R is an alkyl and/or aryl chain.

Description

The invention relates to a foundry molding and core mixture containing an aqueous solution of alkali silicate as a binder.

Foundry molding and core mixtures containing an aqueous solution of alkali silicate are widely used in foundry practice, primarily for the production of molds and cores using carbon dioxide curing. This technology allows for rapid curing of the foundry mixture using available raw materials. The main disadvantage of this process is the poor disintegration of the mixtures after casting, which significantly increases production costs, worsens the working environment, increases the scrap rate, and the like.

These shortcomings are eliminated by the foundry molding and core mixture according to the present invention, containing a grinding material in an amount of 100 parts by weight and, as a binder, an aqueous solution of alkali silicate in an amount of 3 to 7 parts by weight, optionally additives, for example, black coal flour, bauxite and the like. The essence of the invention lies in the fact that the foundry mixture contains from 0.05 to 1.00 parts by weight of an ester of phosphoric acid and an alcohol of the general formula (RO)^PO, where R is an alkyl chain with 1 to 4 carbon atoms and/or an aryl chain with 1 to 2 benzene rings.

The advantage of the foundry mixture according to the invention lies in the significant improvement of the hammering ability after casting, which has a positive effect on the economy of foundry processes. The mixture according to the invention retains all the required properties necessary for the production of high-quality molds and cores, such as sufficient strength of the mixture after hardening and low abrasion of the molds and cores. In addition to maintaining these good properties, the mixture according to the invention has significantly improved hammering ability after casting. While with previously known mixtures it is not possible to release the test core from the casting even after 300 blows, with the mixture according to the invention it is possible to achieve release from the casting with a significantly lower number of blows, as is evident from the examples given.

Tab

240,820

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Claims (1)

SUBJECT OF THE INVENTION 240 820 Foundry molding and core mixture containing 100 parts by weight of slag and, as binder, an aqueous solution of alkali metal silicate in an amount of from 3 to 7 parts by weight, or an additive such as coal flour, bauxite and the like, characterized in that it contains from 0.05 to 1.00 parts by weight of a phosphoric acid ester of the formula (RO) 4 PO, wherein R is an alkyl chain of 1 to 4 carbon atoms and / or an aryl chain of 1 to 2 benzene nuclei;