RU2247155C1 - Briquette used in manufacture of cast iron - Google Patents

Abstract

FIELD: ferrous metallurgy.

SUBSTANCE: briquette includes silicon-containing material, carbon-containing material, and cement as binder. Silicon-containing material includes metallurgical silicon carbide and carbon-containing material includes carbon-siliceous mixture.

EFFECT: improved process of manufacturing castings from synthetic cast irons thanks to simultaneous postcarbonization and modification.

4 cl, 2 tbl, 4 ex

Description

The claimed invention (four options) relates to ferrous metallurgy, in particular to the production of iron-carbon alloys.

Four variants of the technical solution are claimed, which according to each of the variants is the solution of the same problem fundamentally in the same way that cannot be covered by one general claim.

A known mixture for processing cast iron, which contains carbon-containing material, silicon carbide, ferrosilicon and vanadium oxides in the following ratio of components, wt.%:

Carbon material 10-30

Silicon Carbide 1-5

Vanadium Oxide 10-30

Ferrosilicon 75% Else

(A.S. USSR No. 1169996, C 22 C1 / 00. Bull. No. 28, 1985)

This mixture increases the resistance to wear of the treated cast iron.

A known mixture for the treatment of cast irons, containing 75% ferrosilicon, a carbon-containing material and chromium oxides in the following ratio of components, wt.%:

Carbon material 10-30

Silicon Carbide 1-5

Chromium oxides 10-30

75% ferrosilicon rest

(A.S. USSR No. 1266869, C 22 C 1/00. Bull. No. 40, 1986)

This mixture increases the hardness and corrosion resistance of cast iron.

Known modifying briquette containing aluminum, fluorspar, graphite, ferrosilicon and / or silicobarium and a binder in the following ratio, wt.%:

Aluminum 15-35

Fluorspar 2-10

Graphite 2-4

Ferrosilicon and / or

silicobarium rest

In this case, the ligament has the following composition, wt.%:

Magnesium bicarbonate 52.0-56.0

Chromic Anhydride 2.6-2.9

Chromium oxide 11.2-11.9

Titanium dioxide 23.3-26.0

Water rest

(A.S. USSR No. 1498792, C 21 C 1/08, C 22 C 35/00. Bull. No. 29, 1989)

This mixture increases the strength of the briquette and improves the mechanical properties of the processed cast irons.

A known briquette for the production of iron and steel (RF Patent No. 2083681, IPC C 21 C 5/06, C 22 V 1/24). According to this invention, the briquette for the production of iron and steel includes steel oxide, a carbon-containing material and a binder, moreover, a mixture of silicon dioxide, calcium oxide, sodium oxide and aluminum oxide is used as a binder, and an electrode fight is used as a carbon-containing material.

A known briquette containing silicon-containing residues (options), and a method for its preparation. The briquette of this invention contains silicon-containing residues as additives for metallurgical purposes, while it consists in dry weight of 1-10% by weight of cardboard fiber, 5-40% by weight of hydraulic cement, and the rest is silicon (RF Patent No. 2144058, IPC C 22 V 1/242).

The closest in technical essence and the achieved effect are modifying briquettes for synthetic cast iron containing FS-75 ferrosilicon, a binder and a carburizer, coke acts as a carburizer, a 40% aqueous solution of a technical precipitate of technical lignosulfonates as a binder in the following ratio of components, wt. %:

Ferrosilicon FS-75 5.0-8.0

Coke 80.0-85.0

40% aqueous solution of solid precipitate

technical lignosulfonates 10.0-12.0

(A.S. USSR No. 1574667, C 22 C 35/00. Bull. No. 24, 1990)

The composition of these briquettes provides only pre-carbonization of the melt and a decrease in the bleaching of thin-walled castings.

The technical task of this invention is to achieve a qualitative improvement in the composition of the briquette by replacing ferrosilicon with silicon carbide with metallurgical at certain quantitative ratios of all components, which leads to higher technical results - increasing the strength characteristics of iron-carbon alloys and improving the technological process for the production of castings from synthetic cast irons due to their simultaneous pre-carbonization and modification.

The briquettes claimed by this invention (four options) can be used in the production processes of iron-carbon alloys, as well as gray and alloyed cast irons based on synthetic melt, which has a low ability to graphitize.

In the first embodiment, the task is solved in that the briquette for the production of an iron-carbon alloy, including a silicon-containing material, a carbon-containing material and a binder, contains silicon carbide and carbon-containing materials, metallurgical silicon and carbon - a silicon mixture, as a binder - cement in the following ratio of components, wt.%:

Metallurgical Silicon Carbide 59-62

Carbon-siliceous mixture 21-25

Cement 13-20

In the second embodiment, the briquette for the production of iron-carbon alloy includes a silicon-containing material, a carbon-containing material and a binder, contains silicon carbide and carbon-containing materials as silicon-containing and carbon-containing materials, metallurgical and carbon-silicon mixture, cement as the binder in the following ratio of components, wt.%:

Metallurgical Silicon Carbide 44-48

Carbon-siliceous mixture 36-39

Cement 13-20

In the third embodiment, the briquette for the production of iron-carbon alloy includes a silicon-containing material, a carbon-containing material and a binder, contains silicon carbide and carbon-containing materials as silicon-containing and carbon-containing materials, metallurgical and carbon-silicon mixture, cement as the binder in the following ratio of components, wt.%:

Metallurgical Silicon Carbide 18-21

Carbon-siliceous mixture 62-66

Cement 13-20

In the fourth embodiment, the briquette for the production of iron-carbon alloy includes a silicon-containing material, a carbon-containing material and a binder, contains silicon carbide and carbon-containing materials as silicon-containing and carbon-containing materials, metallurgical and carbon-silicon mixture, cement as a binder in the following ratio of components, wt.%:

Silicon carbide metallurgical 1-5

Carbon-siliceous mixture 79-82

Cement 13-20

A sign common to the specified for all variants of the claimed briquettes and the prototype is the presence of silicon-containing material, carbon-containing material and a binder.

A distinctive feature for the first option is the content as silicon-containing and carbon-containing materials of silicon carbide metallurgical and carbon-silicon mixture, as a binder - cement in the following ratio of components, wt.%:

Metallurgical Silicon Carbide 59-62

Carbon-siliceous mixture 21-25

Cement 13-20

A distinctive feature for the second option is the content as silicon-containing and carbon-containing materials of silicon carbide metallurgical and carbon-silicon mixture, as a binder - cement in the following ratio of components, wt.%:

Metallurgical Silicon Carbide 44-48

Carbon-siliceous mixture 36-39

Cement 13-20

A distinctive feature for the third option is the content as silicon-containing and carbon-containing materials of silicon carbide metallurgical and carbon-silicon mixture, as a binder - cement in the following ratio of components, wt.%:

Metallurgical Silicon Carbide 18-21

Carbon-siliceous mixture 62-66

Cement 13-20

A distinctive feature for the fourth option is the content as silicon-containing and carbon-containing materials of silicon carbide metallurgical and carbon-silicon mixture, as a binder - cement in the following ratio of components, wt.%:

Silicon carbide metallurgical 1-5

Carbon-siliceous mixture 79-82

Cement 13-20

The introduction of metallurgical silicon carbide into the mixture ensures the replacement of ferrosilicon. Silicon carbide is used as a component of the charge, providing the necessary content of silicon and partially carbon in cast iron. The use of metallurgical silicon carbide is more economical in comparison with ferrosilicon and helps to reduce the tendency of liquid cast iron to bleach, as well as to a more uniform distribution of spherical graphite inclusions in high-strength cast iron and a more stable silicon content in all cast iron, which significantly improves the technological characteristics of the iron-carbon melt and mechanical properties cast iron.

The influence of metallurgical silicon carbide together with the carbon-silicon mixture ensures the sufficiency of the carburization process. Silicon carbide contains fewer non-metallic inclusions and impurities of non-ferrous metals than ferrosilicon, a lower gas content and contributes to the release of elemental carbon, forms graphitization centers in a liquid melt.

The carbon-siliceous mixture is a secondary product of chemical-thermal reactions with the ratio Csv .: Svob. = 1: 7, provides saturation of the melt with carbon particles, which are active centers of graphitization and also are a source of silicon in the form of SiC.

Thus, in the inventive briquette, the combination of carbon-containing components provides graphitization of cast iron due to the complex effect and at the same time provides a synergistic principle of their action.

The choice of cement as a binder allows the manufacture of briquettes of sufficiently high strength, which significantly reduces the loss of components during their storage and transportation.

The boundaries of the content of the components in the briquette in the first embodiment are justified as follows.

Silicon Carbide (STP 002222-162-99). When the content is in the range of 59-62 wt.%, The bleaching in cast iron is eliminated, and the necessary silicon content is provided. When the content is less than 59 wt.% - the silicon content in cast iron does not meet the vintage. With a content of more than 62 wt.% - the reaction time of the briquettes increases significantly with a low pre-carbonizing effect (the modifying ability of the briquette worsens, the shape of graphite and, as a consequence, the mechanical properties of the castings worsen).

Carbon-siliceous mixture (TUU 322-00196204.005-99). The amount of carbon-silicon mixture in the briquettes in the range of 21-25 wt.% Provides a stable carburizing ability of the briquettes. When the content of the carbon-silicon mixture in the briquette is less than 21 wt.%, Their carburizing ability is insufficient, and when it contains more than 25 wt.%, An excess of carbon appears in comparison with the branded composition.

Cement (GOST 30515-97), for example, grade M-400 provides the necessary strength of briquettes. But when the content of the briquette is less than 13 wt.% Cement, they have insufficient strength, increased scattering. At a content of more than 20 wt.%, The mechanical properties of cast iron deteriorate, the amount of slag increases.

The boundaries of the content of the components in the briquette in the second embodiment are justified as follows.

Silicon Carbide (STP 002222-162-99). When the content is in the range of 44-48 wt.%, Bleaching in cast iron is eliminated, the amount of ferrite in cast iron is increased, and the necessary silicon content is provided. When the content is less than 44 wt.%, The silicon content in cast iron does not correspond to the grade. When the content is more than 48 wt.%, An excess of silicon appears, as a result of which the strength characteristics of cast iron are reduced due to the heterogeneity of the structure of the metal matrix.

Carbon-siliceous mixture (TUU 322-00196204.005-99). The amount of carbon-silicon mixture in the briquettes within 36-39 wt.% Provides a high and stable carburizing ability of the briquettes. When the content of the carbon-silicon mixture in the briquette is less than 36 wt.%, Their carburizing ability is low, when it contains more than 39 wt.%, The shape, size and distribution of graphite inclusions deteriorate, which affects the quality of castings.

Cement (GOST 30515-97), for example, brand M-400. In the claimed amount provides the necessary strength of the briquettes. But when the content of the briquette is less than 13 wt.% Cement, they have insufficient strength, increased scattering. At a content of more than 20 wt.%, The mechanical properties of cast iron deteriorate, the amount of slag increases.

The boundaries of the content of the components in the briquette in the third embodiment are justified as follows.

Silicon Carbide (STP 002222-162-99). When the content is in the range of 18-21 wt.%, The necessary silicon content is ensured, the effect of graphitizing modification is achieved, bleaching is eliminated. When the content is less than 18 wt.%, The silicon content in cast iron does not meet the vintage. When the content is more than 21 wt.%, An excess of silicon appears, as a result of which the strength properties are reduced due to the heterogeneity of the structure of the metal matrix.

Carbon-siliceous mixture (TUU 322-00196204.005-99). When the content in the range of 62-66 wt.% Provides the sufficiency of the carburization process. When the content of the carbon-silicon mixture in the briquette is less than 62 wt.%, The branded composition of cast iron for carbon is not provided, and when its content is more than 66 wt.%, The shape, size and distribution of graphite inclusions deteriorate, which affects the quality of castings.

Cement (GOST 30515-97), for example, brand M-400. In the claimed amount provides the necessary strength of the briquettes. But when the content of the briquette is less than 13 wt.% Cement, they have insufficient strength, increased scattering. At a content of more than 20 wt.%, The mechanical properties of cast iron deteriorate, the amount of slag increases.

The boundaries of the content of the components in the briquette in the fourth embodiment are justified as follows.

Silicon Carbide (STP 002222-162-99). When the content is in the range of 1-5 wt.%, The effect of graphitizing modification is achieved, and the amount of structurally free cementite is reduced. When the content is more than 5 wt.%, An excess of silicon appears in the cast iron, as a result of which the strength properties decrease due to the heterogeneity of the structure of the metal matrix.

Carbon-siliceous mixture (TUU 322-00196204.005-99). When the content is in the range of 79-82 wt.%, The melt is saturated with carbon particles, which are active centers of graphitization. When the content of the carbon-silicon mixture in the briquette is less than 79 wt.%, A sufficient degree is not provided, and when it contains more than 82 wt.%, Graphite leaves the cast iron in the form of a spell, which affects the quality of the castings.

Cement (GOST 30515-97), for example, brand M-400. In the claimed amount provides the necessary strength of the briquettes. But when the content of the briquette is less than 13 wt.% Cement, they have insufficient strength, increased scattering. At a content of more than 20 wt.%, The mechanical properties of cast iron deteriorate, the amount of slag increases.

A search by the applicant for scientific, technical and patent sources of information and a prototype selected from the list of analogues makes it possible to identify the above differences in the proposed technical solution.

So, the proposed technical solution “Briquette for the production of iron-carbon alloy” (four options) meets the criteria of the invention is novelty.

An additional analysis of the known technical solutions to determine the features in them, similar to the features of the characterizing part of the claims of the claimed technical solution, showed that these signs were not found among the known solutions.

Thus, the claimed technical solution meets the criteria of the invention - inventive step.

Examples of specific performance.

1. Briquettes according to the first embodiment are used in the production of synthetic cast iron from a mixture, consisting of 27% steel scrap, 63% of foundry or pig iron, 10% of briquettes according to the claimed invention, for example, for ChS5Sh cast iron (GOST 7769-82).

For comparative studies of briquettes for cast iron smelting, the ChS5Sh cast iron of the following chemical composition was selected as an object of research,%: carbon 2.7-3.5; silicon 4.5-5.5; Manganese ≤ 0.8; phosphorus ≤ 0.10; sulfur ≤ 0.03; chrome up to 0.2; titanium 0.1-0.3; iron the rest.

Synthetic cast iron was melted in an induction furnace LPZ-57 with acid lining. As a metal charge, 27% of steel scrap of grade 1A (GOST 2787-88), 63% of pig iron of grade PL2 (St SEV 3288-92) were used. The melt was overheated to 1450 ° C and 10% of the briquettes were introduced.

The investigated briquette compositions and research results are given in table 1.

2. Briquettes according to the second option are used in the production of synthetic cast iron from a mixture, consisting of 45% steel scrap, 45% foundry or pig iron, 10% of briquettes according to the claimed invention, for example, for SCh10 cast iron (GOST 1412-85), ASF- 5 (GOST 1585-85).

For comparative studies of briquettes for cast iron smelting, ASF-5 cast iron of the following chemical composition was selected as an object of research,%: carbon 3.5–4.3; silicon 2.5-3.5; manganese 7.5-12.5; phosphorus no more than 0.20; sulfur not more than 0.06; chrome up to 0.2; iron the rest.

Synthetic cast iron was melted in an induction furnace LPZ-57 with acid lining. 45% steel scrap of grade 1A (GOST 2787-88), pig iron of grade PL2 (St SEV 3288-92) was used as metal charge. The melt was overheated to 1450 ° C and 10% of the briquettes were introduced.

The investigated briquette compositions and research results are given in table 1.

3. Briquettes according to the third embodiment are used in the production of synthetic cast iron from a mixture, consisting of 63% steel scrap, 27% foundry and pig iron, 10% of briquettes according to the claimed invention, for example, for SCh 30-35 cast iron (GOST 1412-85) ASCh-2 (GOST 1585-85).

For comparative studies of briquettes for smelting cast iron, the SCh35 cast iron of the following chemical composition was selected as the object of research,%: carbon 2.9-3.0; silicon 1.2-1.5; manganese 0.7-1.1; phosphorus ≤ 0.2; sulfur ≤ 0.12; iron the rest.

Synthetic cast iron was melted in an induction furnace LPZ-57 with acid lining. As a metal charge, 63% of steel scrap of grade 1A (GOST 2787-88), 27% of pig iron of grade PL2 (St SEV 3288-92) were used. The melt was overheated to 1450 ° C and 10% of the briquettes according to the claimed invention were introduced.

The investigated briquette compositions and research results are given in table.2.

4. Briquettes according to the fourth embodiment are used in the production of synthetic cast iron from a mixture consisting of 90% steel scrap and 10% of briquettes according to the claimed invention, for example, for ChS17 cast iron (GOST 7769-82).

For comparative studies of briquettes for smelting cast iron, the ChS17 cast iron of the following chemical composition was selected as an object of research,%: carbon 0.3-0.5; silicon 16.1-18.0; Manganese ≤ 0.8; phosphorus ≤ 0.10; sulfur ≤ 0.07; iron the rest.

Synthetic cast iron was melted in an induction furnace LPZ-57 with acid lining. 90% steel scrap grade 1A (GOST 2787-88) was used as a metal charge. The melt was overheated to 1450 ° C and 10% of the briquettes were introduced.

The investigated briquette compositions and research results are given in table.2.

For all swimming trunks:

The cast irons were kept for 10 minutes and adjusted to the required chemical composition with additives of ferroalloys and the necessary alloying elements.

After slag removal, standard technical samples ⌀ 30 mm were poured to study the mechanical properties of cast iron and determine the chemical composition of the metal.

As can be seen from tables 1, 2, the proposed briquettes provide an increase in strength characteristics by 7-13% for cast iron of its group, with a more technologically advanced process for the production of cast iron - simultaneous pre-carbonization and modification.

The proposed composition of the briquettes can be easily reproduced and used for the production of high-quality iron-carbon melts.

Thus, the claimed technical solution (four options) meets the criteria of the invention - industrial applicability.

Table 1 Cast iron briquette Ingredient Limits The composition of the briquettes, wt.% The carbon content in the base melt,% The carbon content in cast iron after treatment with briquettes,% The effect of carbonization Temporary resistance of cast iron in tension, MPA Silicon Carbide Metallurgical Ferrosilicon Carbon-siliceous mixture Binder GOST Experience Famous SCH-25 Average 7.0 83.0 10.0 2.74 3.31 0.208 252 252 The proposed briquette according to the first option ChS5Sh GOST 7769-82 Lower 59 - 21 thirteen 1.9 2.7 0.421 290 316 Average 60.5 - 23 16.5 1.9 3,1 0.631 290 316 Upper 62 - 25 twenty 1.9 3,5 0.969 285 308 Below the bottom 58 twenty 12 1.9 2.1 0.105 310 347 Above the top 63 26 21 1.9 3.8 1 270 289 The proposed briquette according to the second option ASF5 GOST 1585-85 Lower 44 - 36 thirteen 1,5 3,5 1.33 100 109 Average 46 - 37.5 16.5 1,5 3.8 1,53 120 132 Upper 48 - 39 twenty 1,5 4.3 1.87 128 140 Below the bottom 43 35 12 1,5 3.0 1 138 155 Above the top 49 40 21 1,5 4.8 2.2 90 102

Table 2. Cast iron briquette Ingredient Limits The composition of the briquettes, wt.% The carbon content in the base melt,% The carbon content in cast iron after treatment with briquettes,% The effect of carbonization Temporary resistance of cast iron in tension, MPA Silicon Carbide Metallurgical Ferrosilicon Carbon-siliceous mixture Binder GOST Experience Famous SCH-25 Average 7.0 83.0 10.0 2.74 3.31 0.208 252 252 The proposed briquette according to the third option SCH35 GOST 1412-85 Lower eighteen - 62 thirteen 0.8 2.9 2,629 348 379 Average 19.5 - 64 16.5 0.8 2.95 2,687 350 395 Upper 21 - 66 twenty 0.8 3.0 2.75 350 395 Below the bottom 17 - 61 12 0.8 2,8 2,5 305 335 Above the top 22 67 21 0.8 3.2 3.0 310 338 The proposed briquette according to the fourth option ChS-17 GOST 7769-82 Lower 1 - 79 thirteen 0.1 0.31 2.1 59.5 67 Average 3 - 80.5 16.5 0.1 0.45 3,5 60.0 67 Upper 5 - 82 twenty 0.1 0.50 4.0 61.5 69.5 Below the bottom 0.5 78 12 0.1 0.28 1.8 55 60.5 Above the top 6 83 21 0.1 0.55 4,5 54 59

Claims (4)

1. The briquette used in the production of cast iron, including a silicon-containing material, a carbon-containing material and a binder, characterized in that it contains metallurgical silicon carbide as a silicon-containing material, contains a carbon-silicon mixture as a carbon-containing material, and cement as a binder in the following ratio of components , wt.%: Metallurgical Silicon Carbide 59-62 Carbon-siliceous mixture 21-25 Cement 13-20 2. The briquette used in the production of cast iron, including a silicon-containing material, a carbon-containing material and a binder, characterized in that it contains metallurgical silicon carbide as a silicon-containing material, contains a carbon-silicon mixture as a carbon-containing material, and cement as a binder in the following ratio of components , wt.%: Metallurgical Silicon Carbide 44-48 Carbon-siliceous mixture 36-39 Cement 13-20 3. The briquette used in the production of cast iron, including a silicon-containing material, a carbon-containing material and a binder, characterized in that it contains metallurgical silicon carbide as a silicon-containing material, contains a carbon-silicon mixture as a carbon-containing material, and cement as a binder in the following ratio of components , wt.%: Metallurgical Silicon Carbide 18-21 Carbon-siliceous mixture 62-66 Cement 13-20 4. The briquette used in the production of cast iron, including a silicon-containing material, a carbon-containing material and a binder, characterized in that it contains metallurgical silicon carbide as a silicon-containing material, contains a carbon-silicon mixture as a carbon-containing material, and cement as a binder in the following ratio of components , wt.%: Silicon carbide metallurgical 1-5 Carbon-siliceous mixture 79-82 Cement 13-20