SU1507505A1 - Sand for making cores of filter inserts of gate system - Google Patents

Abstract

The invention relates to foundry and can be used to make casting rods of filter inserts of the gating system, mainly in the manufacture of large-size castings using melted models. The purpose of the invention is to increase the strength of the mixture and the quality of castings by reducing non-metallic inclusions. This is achieved by incorporating sodium chloride into the mixture. The mixture contains (wt.%): Marshall 31.0 ... 35.0

sodium silicofluoride 12.0 ... 15.0

liquid glass 9.0 ... 16.0

lacquer based on pentaphthalic resin modified with vegetable oil 0.3 ... 1.0

sodium chloride 1.0 ... 3.0

refractory filler based on quartz sand else. The ratio of sodium chloride to sodium fluoride is 1: (5-12). The introduction of sodium chloride in the mixture contributes to its decomposition when heated above 800 ° C to atomic chlorine and sodium. Chlorine bubbles float to the top of the sprue funnel, filter the molten liquid steel. 1 hp f-ly, 1 tab.

Description

The invention relates to foundry and -can be used to make cores in the production of casting on melted models.

The purpose of the invention is to increase the strength of the mixture and the quality of castings by reducing non-metallic inclusions.

The proposed mixture contains quartz sand and marshalite as a refractory base, and liquid glass as a binder. The hardener is sodium silicofluoride. A mixture

also contains technological additives: lacquer based on pentaphthalic resin, which serves as a plasticizer, and

sodium chloride to increase the purity of the mixture and the refining of molten steel. The sodium chloride introduced into the mixture, upon contact with the steel melt, evaporates from the surface of the mixture, decomposing into atomic chlorine and sodium. M.p. NaCl 8004, bp 1440 ° C.

Chlorine puffs, striving to float to the top of the liquid bath, filter the melt. Nemetll

ate: p

3150

In a suspended state, when they collide with puffs of chlorine, they adsorb onto their surface, which float to the upper part of the sprue funnel, while the most purified steel melt enters the casting mold. Sodium, found to be found in molten steel, goes into slag without significantly affecting the mechanical properties of the steel.

The preparation of the mixture is carried out as follows.

Marshallite, sodium silicofluoride, quartz sand and sodium chloride are poured into a metal container and mixed thoroughly, then liquid glass and varnish are introduced into the mixture and mixed to obtain a homogeneous composition of the mixture.

Rods are made from the prepared mixture in metal core boxes, which are dried at 150-, and then prokashivayu together with the forms at 800-900 ° C.

The introduction of sodium chloride into the mixture leads to the formation of a liquid phase during the calcination of the filter inserts, since the melting point of sodium chloride is 800 ° C. To prevent this disadvantage, the sodium silicofluoride content in the mixture should be at least 12–15%.

Sodium silicofluoride (), being a hardener, at high temperatures neutralizes the negative effect of sodium chloride, giving a high strength to the rod. Therefore, the ratio of sodium chloride to sodium fluoride in the mixture should be at least 1: (5-12).

The compositions of the proposed mixtures and their technological properties are given

505

in the table. The data obtained show that the use of the proposed mixture increases the strength of the mixture by

 compared with the famous. Cast marriage is reduced by 10-12%.

Claims (2)

1. Mixture for making rods of filter inserts of the gating system, mainly in the manufacture of large-sized castings according to melted models, including refractory filler based on quartz sand, liquid glass, marchesite, sodium silicofluoride and varnish based on pentaphthalic resin modified with vegetable oil, characterized in that, in order to increase the strength of the mixture and the quality of the castings by reducing non-metallic inclusions, it additionally contains sodium chloride in the following ratio SRI ingredients, wt.%: 0 five 0 Marshalit Fluorosilicate sodium Liquid glass Varnish based on pentaphthalic resin, modified with vegetable oil Sodium chloride Quartz sand based refractory filler 31.0-35.0 12.0-15.0 9.0-16.0 0.3-1.0 1.0-3.0 Rest 2. Mixture POP.1, characterized in that, in order to increase its strength, the ratio of sodium chloride and silicofluoride is 1: (5-12).