SU501828A1 - Thermal insulation mixture to insulate the profit of castings - Google Patents

Description

The invention relates to the field of the foundry industry, in particular to the mixtures used for the thermal insulation of black and color castings.

Teplyuizol and dionic mixtures are known for insulating the profits of castings from ferrous and non-ferrous alloys, consisting of expanded perlite, refractory clay, and liquid glass.

Mixtures of such composition have lowered physical and mechanical characteristics in dry and wet conditions, which makes it difficult to manufacture casings, especially large ones. In addition, this mixture has a low heat resistance, which leads to a significant melting of the walls of the shells and, accordingly, to a decrease in the heat-insulating effect.

The purpose of the invention is to increase the heat insulating and physical properties of the mixture, as well as to reduce the degree of fusion of the mixture upon contact with the liquid metal.

This goal is achieved due to the fact that the proposed warmth: the insulating mixture of refractory materials does not contain an expanded porous material having a volume weight of 250-500 / sg / m3, a thermal conductivity of 0.1-0.14 / rock / .and X Hz hail and temperature range is 1115–1380 ° C with the following ratio of ingredients, in weight. %:

Expanded perlite Expanded porous

material

Refractory clay Liquid glass module 2.35-2.7

As an expanded porous material with the specified properties, the heat insulating mixture contains or shchapgizit in the amount of 25-60 weight. %, or slag pumice in the amount of 1.0-80 weight. %

Last has the following composition

in weight. %:

Silica oxide

33.4-40.1 Aluminum oxide

12.3-17.7 Calcium Oxide

36.2-44.7 Manganese oxide

3.5-3.6 Magnesium Oxide

3.4-4.2 Iron Oxide

0.4-1.3.

The volumetric weight of slag pumice of such a composition (f | cc of its ingredients is 3-10 mm) is 450-670 kg / m, the temperature of the beginning of melting is 1340-1380 ° C, those plops | p01water "Ost 0.150-0.225 w / m ° s

Shungizite is an expanded material obtained by high-temperature firing of Karelian shunlysite

shale, which is metamorphic sedimentary rocks and dense structure. In contrast to conventional shale, the schungizite rocks contain a special form of graphite, which is able to swell during firing. The temperature of expansion of these rocks is in the range from 1115 to 1240 ° C. The specific weight of shungieite is 2.1-2.4 g / cm, the volume weight of expansion of the material is 0.200-0.400 g / ssf, the porosity of the intragrain granules .v - 60% emptiness of 45%.

The conductivity of shungizite with a bulk weight of 0.2-0.4 g / cm and natural humidity is 0.09-0.12 kcal / m h / ha or 0.10-0.14 w / m ° C. The temperature of the beginning of fusion of schungizite grains is 90–120 ° C higher than the expanded perlite. In addition, in terms of the particle size distribution, shungieite is much larger than the expanded perlite, thereby reducing the content of low-melting C | B in its liquid glass in the mixture. The use of slag pumice in the mixture also reduces the content of expanded perlite and liquid glass.

The properties of the compositions of mixtures are shown in the table

Physical and mechanical properties

Compressive strength

raw, kg / cm Compressive strength

in dry condition, kg / cm

kg / cl Gas permeability

in dry condition. Volume weight of dry mix, kg / m3

Thermophysical properties of mixtures

Heat capacity, kj / kg ° C Thermal conductivity, W / m C Heat permeability,

w / sec ° C Temieraturon conductivity,

ahU / s

The mixtures of these compositions have higher fiziko-mechicheskimi indicators, have greater heat resistance when in contact with the liquid metal and allow you to reduce the size of profits in 1.9-3.2 times.

Claims (4)

1. Insulating, and the mixture for insulating the profit of castings from ferrous and non-ferrous alloys, which includes expanded perlite, mainly apneu- rious, liquid glass, characterized in that, in order to increase the thermal insulation, fi.I | KO-L1eha; reduce the stppe "and blend the mixture with jcoHTaKTe with a liquid metal, a mixture of additional; 0 contains an expanded porous material having a volume weight of 250-500 kg / m, heat conduction 0.1-0.14 kcal / m h And the melting point is as follows weight. %: Swollen Parlite Bruised (Wavy material Flameproof glia 2. A mixture according to claim 1, characterized in that as an expanded porous material with the indicated properties, the mixture contains schungisite in an amount of 25-60 sec. % 3. A mixture according to claim 1, characterized in that as an expanded porous material with the indicated properties, the mixture contains slag pumice in the amount of 10 to 80 wt. % 4. The mixture according to claim 3, wherein the slag pumice stone has the following composition, 5 in weight. %: 501828 6 Silica 33.4-40.1 Oxide; 12.3-17.7 Calcium Oxide 36.2-44.7 Manganese Oxide3.5-3.6 Magnesium Oxide 3.4-4.2 Ferrous Oxide 0.4-1.3.