'mixture of impression material, and method for preparing a refractory impression material'

摘要

A mixture of molding material for producing metalworking casting molds, particularly for non-ferrous metals such as aluminum or magnesium, is intended to reduce problems such as metal-mold reaction defect and / or shrinkage porosity. the fluid refractory impression material in the impression material mixture is coated with a mixture of inorganic salts having a eutectic melting point in the range of about 400 c to about 500 c, particularly in the range of about 420 c to about 460 ç. preferably this coating occurs by contacting the mixture of inorganic salts with the mixture of impression materials at a temperature between 500 ° C and 700 ° C, in a manner that maintains the fluid nature of the coated product. a mixture of inorganic salts that is used is a mixture consisting of, by weight: 74% potassium fluorborate; 15% potassium chloride; and 12% potassium fluoride. This mixture has a eutectic melting point of 420 c.