SU1592085A1

SU1592085A1 - Sand for making moulds and cores

Info

Publication number: SU1592085A1
Application number: SU874372216A
Authority: SU
Inventors: Yurij F Voronin; Lidiya D Kachanovskaya; Vladimir A Ilinskij; Fedor D Ovcharenko
Original assignee: Yurij F Voronin; Lidiya D Kachanovskaya; Vladimir A Ilinskij; Fedor D Ovcharenko
Priority date: 1987-12-21
Filing date: 1987-12-21
Publication date: 1990-09-15

Description

The invention relates to foundry and can be used

The invention relates to foundry and can be used for the manufacture of molds and cores of liquid-glass mixtures, curable by heat drying and carbon dioxide.

The purpose of the invention is to increase the strength of the mixture and improve its knockability.

The proposed mixture contains a binder; liquid glass, finely divided mineral, for example, chalk or kaolin, modified with a mixture of sulfanilic acid and silane in a molar ratio of 2: 1, and a refractory filler. Refractory filler is2

It is designed for the manufacture of molds and cores from liquid glass mixtures, cured by heat drying and carbon dioxide. The purpose of the invention is to increase the strength of the mixture and improve its knockability. This is achieved through the use of 0.6-1.2 wt.% Chalk or kaolin modified with 0.05-1.0 wt.% Sulfanilic acid and silane, taken in a molar ratio of 2: 1, as a technological additive in the liquid-glass mixture. . Introduction to the mixture of such a softening additive contributes to the formation of polymer bonds, less heat-resistant than the main ones in liquid glass. As a result, the strength of the mixture increases, and when the mixture is heated in the process of pouring molds and rods with metal, less heat-resistant polymeric bonds are easily weakened and the mixture is destroyed. 2 tab.

The basis of the mixture is molding sand, cooled to a temperature not higher than 25 ° С, with a humidity not exceeding 0.5%. Liquid sodium glass in the mixture, it is advisable to use with a silicate module 2.7-3.0 and a density of 1.38-1.44 g / cm ³ .

* Modified chalk or kaolin is a finely ground powder, pretreated with a mixture of sulfanilic acid and silane in a 2: 1 ratio. Processing is carried out dry or wet by mechanical mixing of materials, and in conditions

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1592085

surface dissolution of particles of material. As a result, reaction hydrocarbon radicals involved in the binding process of colloidal particles are grafted onto the surface of the finely divided material. The mineral processed in this way for up to 6 months does not lose its properties.

In the process of interaction of the fine modified mineral with liquid glass during curing, the formation of polymeric bonds is less likely to occur that are less heat-resistant than the basic ones in liquid glass. The formation of these bonds leads to an increase in the strength of the proposed mixture in comparison with the known, containing ordinary, unmodified minerals. Subsequently, under the thermal effect of the cast metal, the less thermally stable polymer bonds are softened, as a result of which the shape or core substantially loses its strength and, with 25 knockouts, is easily removed from the casting.

Preparation of the mixture is as follows.

A refractory filler is loaded into the roller mixer, then the modified natural material is introduced into the mixer and mixed for 1-1.5 minutes. After that, a liquid glass is introduced and stirring is continued for 4-5 minutes.

The compositions of the proposed mixtures are given in Table 1.

Technological properties of the proposed mixtures are given in Table 2;

40

The mixtures presented in Table 1 are cured at 220 ° C for 7 minutes. A part of the samples is tested immediately after cooling, and a part of the sample is subjected to subsequent heat treatment in a muffle furnace at 800 ° C for 1 hour and cooled together with the furnace, after which it is also tested under tension.

The indicators presented in table 2 indicate that the introduction of liquid glass, a mixture of modified chalk or kaolin to the composition increases the strength properties of the mixture in the cured state and almost completely weakens the mixture during heat treatment according to the standard technique. The softener mixture is almost destroyed by the pressure of the fingers.

Implementation of the invention allows to reduce the consumption of liquid glass while maintaining high strength and significantly reduce the complexity of the knockout of liquid mixtures from castings. In this case, the curing of the mixture can be both thermal and carbon dioxide.

Claims

Claim

The mixture for the manufacture of foundry molds and cores, including refractory filler based on silicon dioxide, liquid glass and technological additive, characterized in that, in order to increase the strength of the mixture and improve its knockability, it contains as a technological additive chalk or kaolin, modified 0,051, 0 wt.% Sulfanilic acid and silane, taken in a molar ratio of 2: 1, and the components have the following ratio, wt.%:

3-5 liquid glass

Chalk or kaolin,

modified 0.05-1% by weight of sulfanilic acid and silane,

. taken in molar ratio

. 2: 1, 0.6-1.2 Refractory on. filler on

dioxide based

silicon rest

Ζ

1592085

five

Table 1

Ingredients

Content of ingredients

wt.%, in mixtures

one —-— y-5 6 2 3 four Quarrie sand KO2A 96.4 95.1 93,8 96.4 95.1 93,8 Liquid glass M = 2.7 ^ = 1.4 g / cm ^ 3.0 4.0 5.0 3.0 4.0 5.0 Chalk modified • ry 0.6 0.9 1.2 - ") Kaolin Modify cyber - 0.6 0.9 1.2

table 2

Properties Mixes one 2 1 ³ four five 6 Tensile strength in the cured state, MPa 1.02 1.55 1.97 1.27 1.94 2.55 Tensile strength after heat treatment, MPa Not 0.02 0.02 Not 0.02 0.02 Compressive strength in wet condition, MPa 0.02 0.02 0.03 0.02 0.02 0.03 Vitality, h 6 6 6 6 6 6