SU764825A1 - Mould composition - Google Patents

Description

The invention relates to foundry (production, in particular, to molding mixtures for raw single forms.

A known moldable mixture for mold isotovleni, consisting of 3 quartz sand, clay or bentoit, ground coal and

This mixture has insufficient strength in the wet state and low fluidity.

A sandy-clayey mixture is also known, including a refractory filler, molding clay, water and the addition of polyalkylamines 2. The addition of polyalkylamines increases the fluidity of the mixture, but it requires a long mixing of the molding materials and in the mixing preparatory runners (within 3-10 minutes). The mixture provides the forms with the strength in the wet state of 0.2-0.3 kgf / cm.

Closest to the proposed technical essence and the achieved result is a mixture for the manufacture of casting molds, containing a refractory filler, binding ground lignosulfonates ground metallurgical slag (cupola or marten) with basicity 0.81, 8 and refractory clay And.

This mixture provides molds with a strength in the wet state of 0.3-0.5 kgf / cm. However, it is characterized by low turnover. In addition, the total content of metallurgical slag and the need for it to be evenly distributed in the mass of other dry ingredients (quartz sand, clay) place high demands on the quality of mixing and drastically lengthen the mixing process itself.

The purpose of the present invention is to shorten the duration of the mixing preparation and increase the flowability and strength of the mixture in its raw state.

To achieve this goal, the mixture for manufacturing molds of molds, including refractory filler: a lignosulfonate binder, ground metallurgical slag with a basicity of 0.8-1.8 and refractory clay, additionally contains soda ash, ground coal and fuel oil on the next the ratio of ingredients, wt.%:

St. Zuknea based

lignosulonate 1,2-2,4

Metallurgical metallurgical LonaK with a basicity of 0.8-1.83.0-7.6

Refractory clay 1.0-3.5 Ground coal 0.2-2.2 Soda ash 0.10-0.15 Fuel oil, $ 05-0.2

Refractory filler Else Both ordinary refractory and bentonites can be used as molding clay. Quartz sand, spent molding sand, crushed quartzite or chamotte, cirrocone and olivine sand, etc. can be used as a refractory filler, etc. slag with a basicity of 0.8-1.8 of the cupola or open-hearth production, as provided for in accordance with a known technical solution. As a binder containing lignosulfonates, a sulphite-yeast brewing liquid concentrate (GOST 8179-74) or sulphite-alcohol bard CSB (GOST 8518-57) can be used.

reducing the content of ground metallurgical slag and the introduction of fuel and ground coal as compared with the known mixture reduces the mixing process and the consumption of the binder. Increasing the amount of ground slag and ground hard coal above the upper limit decreases the fluidity of the mixture and its strength in the raw CONDITION, as well as the mixing process itself, and when the content is below the lower limit, the mixture does not have the necessary antiburning properties.

When the content of fuel oil above the upper limit of the mixture is characterized by

increased flue gas in the pouring conditions, which impairs the sanitary and hygienic working conditions, and when it is kept below the lower limit, the mixture does not possess the required antiburning properties.

When the content of soda ash below the limit deteriorates the vitality and fluidity of the mixture, while its content is above the upper limit, there is no further improvement in its technological properties.

The proposed mixture is prepared in mixing runners by mixing the dry ingredients with the subsequent introduction and mixing of 5 binders based on lignosulfonates, fuel oil and soda ash.

In tab. 1 shows the compositions proposed (fP№ 1-3), and known (№ 4) mixtures.

The physicomechanical and technological properties of mixtures Nos. 1–4 are listed in Table. 2

Tests have shown that the optimal duration of mixing in continuous runners is: for mixture No. 4-45 s, for mixture No. 2-60 s, for mixture No. 3, 75 s, and FOR: mixture No. 4-135 s. The proposed mixture has high physical and mechanical properties and technological properties, in particular, as can be seen from Table 2, has improved fluidity and increased strength in the state, provides 35 uniformly compacted molds and high-quality castings with any rational compaction method and can be used to produce ferrous alloy castings.

Table 1

1.5

3.0

0.05 0.10

93.25 0.16 0.12 88.92 0.25 0.15 85.10

88.0 Compressive strength in wet state, kgf / cm0,651.08 Orlov fluidity,% 7281 Fisher fluidity,% 6570 Gas permeability, unit 108120 Blendability,%: cast iron sample, 1450 С00 steel sample, 1600 ° C3O Strength in the zone of moisture condensation, kgf / cm 0.0400.052 Formability index,%: 0.90.8

Claims (2)

1. Aksenov p. N. Foundry technology. M., Mashgiz, 1957, pp.64-65. . 2. Patent of Germany No. 1217029, class, in 1/22,, published. 1967. 3, USSR author's certificate 607636, cl. B 22 C 1/02, 1976, 0.920.48 8564 7256 9698 O, O 13 0.0450.035 0.60.6