UA74671U - Stone casting - Google Patents

Abstract

A stone casting comprises SiO, AlO, FeO, FeO, CaO, MgO, NaO, CrO, and MnO. It additionally contains TiO.

Description

The useful model belongs to the production of stone-cast products and can be used to protect metal structures and aggregates in conditions of elevated temperatures (200-900 C) at enterprises of metallurgical, chemical, mining and beneficiation, energy and other industries.

A well-known stone cast (A.s. 804585, IPC SO3Z Z 3/22, publ. 02.15.81), which contains: 5iO» 42-43; Ai2Oz 17-19; BeO 6.5-7.5; HegOz 4.5-5.6; Ca 13.5-14.5; MoD 1.5-2.5; MagO 5.5-6.0; Si2O3 1.5-2.0; MPO 0.2-0.3; TiO" 0.3-0.8. The disadvantage of this stone casting is its low heat resistance and strength.

The closest to the proposed one is a stone cast (A.s. 1433939, IPC СО4В 30/00, publ. 11/30/88, prototype), which contains: 5iO» 51-55; AIgOz 5-12.0; BeO 0.8-1.2; BegOz 3.2-5.8;

Sas 18.0-27; ModO 4.0-6.0; MagO 1.5-2.5; Si2Oz 1.5-2.5; MPO 0.7-1.2.

Also included in the composition of the specified stone casting: 5oz 0.3-0.6.

The disadvantages of the well-known stone casting include the fact that it contains a high percentage of iron oxides (HebzhRegOz), which increases the amount of magnetite released, which has a volume thermal expansion at 700-900 "С reaching 4 95, i.e. in 1.5-2 times more than neighboring mineralogical phases, which leads to significant local internal stress and a decrease in thermal resistance.

Also, the well-known stone casting has a low content of Mo9O, which reduces the crystallization ability of the melt and contributes to the formation of heterogeneous structures along the cross-section of the casting, an increase in internal stress, which also leads to a decrease in the heat resistance of the products.

The basis of a useful model is the task of developing a composition of stone casting, which would have increased characteristics of heat resistance and strength due to the reduction of the residual stress of the structure.

The problem is solved by the fact that the stone casting includes 5iO", АЙ2Oz, EeO, EegOz, ba, MoO, Mago, Si2Oz, MpO, according to a useful model, it additionally contains TiOg at the following ratio of components, by mass. 9 o'clock:

ZO" 57.22-55.8; AIg2Oz 9.13-6.0; Sao 21,6-17,4;

M9O 14.22-12.0; MagO 3.17-1.2; Si2Oz 1.81-0.4;

EegOz 1.54-0.5; Be 0.4-0.1; Those" 0.25-01;

From Mpo 0.35-0.1.

Examples of a specific implementation of a useful model are given in Table 1.

Table 1

Examples of compositions of stone casting

Transfer 1 2 Z (prototype)

AROz 7777717 17711117761 1771193 Y7111171601171111111501 beOz /////////// 1777171717171008777 77111154 77711105

Me 7777/7177771717110и1111117 1771111 055... | 2 shTs (RMRLT .Y.|i7/7SS/701S

WHAT" 77771717177171717117102 | 1025 Hume 6 shDsh shfP -

PETE EV PON PON KO NO ZH

Table 2 shows the physical and mechanical characteristics of stone casting compositions.

Table 2

Physico-mechanical characteristics of RReMeto 4 stone casting compositions (prototype)

Temperature"C at liquidus 1300 1320 1350 1280 liquidus

Heat resistance, heat change, 900-20 "C on plates 200x200x25 MM 22 28 30 20

Compressive strength, MPA (on samples 20x20x20 mm) 185 280 280 220

Rocks, pereclazochromite, quartz sand, blast furnace slag, dolomite, etc. can serve as raw materials for stone casting.

Before loading into the furnace, raw materials are crushed, sifted and dosed in the required quantities. The melting temperature of the proposed compositions of stone casting is not less than 1300 "C. The charge is melted in electric arc furnaces or rotating furnaces at a temperature of 1450-1550 C. The finished melt is lowered from the furnace into the pouring hopper for the preparation of the melt before pouring. The prepared melt is poured in earthen or metal molds heated to 250-300 C. The temperature of the melt that is poured is 1240-1280 "C. Castings are kept for 6-8 minutes and cooled in a tunnel furnace at a rate of 30-50 "C per hour.

The proposed composition of stone casting with the specified ratio of components reduces the number of mineralogical phases to a minimum, ensures uniformity of the structure of castings, reduction of residual and shrinkage stress, and, as a result, an increase in heat resistance.

As a result of reducing the tension of the structure, the obtained material has increased heat resistance - up to 30 thermal changes and compressive strength up to 280 MPA, which is higher than the known material, by 27 95 and 50 95, respectively.

The use of the proposed stone molding will allow to increase the heat resistance and strength of plates and other shaped products made from it, to ensure their service life up to 10 years.

Claims (1)

FORMULA OF A USEFUL MODEL Stone casting, including 5iO2, AI2Oz, ReO, EegOz, CaO, MoO, Mago, Si2Oz, Mpo, which is distinguished by the fact that it additionally contains TiO" with the following ratio of components, by weight. 9: ZO» 57.22-55.8 AgOz 9.13-6.0 Cao 21.6-17.4 Mao 14.22-12.0 Mago 3.17-1.2 Si2Oz 1.81-0, 4 EegOz 1.54-0.5 EeeO 0.4-0.1 TO: 0.25-0.1 Mpo 0.35-0.1.