SU720025A1 - Slag forming mixture for steel casting - Google Patents

Description

one

The invention relates to ferrous metallurgy. And can be used in steel casting.

Known exothermic slag-forming briquette 1, containing, in weight. ° / o: Aluminum powder4-10

Silikokaltsy15-25

Manganese Ore15-20

Fluorspar15-20

Silicate clump20-28

Soda Ash 3-7 Cooked Salt2-5

Liquid glass10-15

The disadvantages of exothermic slag-forming briquette are the abundant smoke emission due to the content of briquette of sodium chloride and soda ash in the mixture, which decompose at steel casting temperatures, which impairs the sanitary working conditions, and a slight effect on the nature and form of non-metallic inclusions and on the macrostructure of the steel ingot.

Also known is a slag-forming briquette for continuous casting of steel 2, containing, by weight. %:

Fluorspar15-20

Manganese Ore15-20

Aluminum powder4-6

Silikokaltsiy20-25

Liquid glass10-15

Silicate cubeEverything.

The disadvantage of the slag-forming briquette is that it has an inadequate modifying effect on the metal, as a result of which the ingot fails to obtain optimally shaped non-metallic inclusions, which ultimately adversely affects the contact endurance of products, for example, rolling bearings. In addition, ingots are prone to the formation of surface defects. Their removal requires stripping and loss of 0.5 / o metal.

The purpose of the invention is to improve the quality of steel and increase the yield by increasing the purity of steel by nonmetallic inclusions, changing its morphology and reducing the sulfur and oxygen content in the finished steel and, as a consequence, increasing its density and improving surface quality.

The goal is achieved by the fact that a slag-forming mixture, including aluminum powder, silicocalcium, manganese ore, fluorite staple, silicate lump, liquid glass, additionally contains silicobarium in fractions with a size of 2-40 mm, with a ratio of components, weight. %:

4-8

Aluminum powder

15-20 Silikokaltsy

15-22 Manganese Ore

15 5

-25 fluorspar

-15

Liquid glass 13-35

Silicobarium Else.

Silicate clump

Barium silicobarium

is surface active.

Barium in silicobarium is a surfactant element, a strong deoxidizing agent and a globlizer, which favorably changes the morphology of non-metallic inclusions, improves the technological plasticity of the metal, its density and, by changing the quality characteristics, increases the yield of the metal.

When cooking, for example, from a slag-forming mixture of briquettes, water glass is used as a binder. The briquette consumption when casting steel into molds is 2-4 kg / ton steel. The granulometric composition of the components of the briquette mixture determines the optimal burning rate of the briquette and should be the following, mm:

Aluminum powder 0.2-1.5

0.2-2.0

Silikokaltsy 0,1 - 1,0

Manganese ore 0.1 -1., 0 Fluorspar 0.2-2.0 Silicate lump 10-40. Silicobarium In the preparation of slag-metal granules for steel casting into the mold, the granulometric composition of the slag-forming mixture remains the same as in the preparation of briquettes, except for the size of the pieces of silicobar, which should be 2-10 mm in diameter. Silicobarium in pieces with a fraction size of mm is moistened with liquid glass and coated with a mechanical mixture consisting of aluminum powder, silicocalcium, manganese ore, fluorspar, silicate lump on a plate granulator, dried and then served as a slag metal granule on the surface of the liquid metal to the crystallizer . The consumption of pellets made from the slag-forming mixture is 1.2-2.0 kg / t-steel.

The size of the silicobar pieces when casting into molds is determined by the consumption of the briquette during the casting process. For example, for a slice of 6.5 tons, the size of the pieces is maximum and is 35–40 mm, and for casting, the size of the pieces into an ingot of 4.2 tons is 10–15 mm.

When casting into the mold, slag-metal granules with a size of 2-10 mm are evenly distributed on the metal surface.

When casting steel, the consumption of silicobar is 13-15 / o of the total mass of slag-forming mixture.

When casting a boiler steel grade 20K, the silicobar consumption is up to 25% of the total mass of the mixture. Steel grade 20K, containing line silicate and sulphide inclusions, has low mechanical properties. Casting 20K steel under a slag-forming mixture containing silico barium eliminates the harmful effects of sulfur in the casting process and, consequently, improves the mechanical properties of the steel.

Examples of compositions, slag-forming mixtures are presented in the table.

A. Puminium powder

С or cocalcium Manganese ore Fluorspar Liquid glass Silicobarium Silicate lump

five

17 22 25 10 13

Claims (2)

8 When casting bearing steel into an ingot of 4.2 tons, before applying the metal to the bottom of the mold, a slag-forming briquette is made of a mixture of the proposed composition, the consumption of which is 3 kg / t of steel. The size of the silicobar pieces is 10 mm. In the casting process, liquid-liquid homogeneous active slag is obtained from the liquid metal side. In the upper part, the briquette during the casting process remains sufficiently strong and retains the dimensions corresponding to the inner walls of the mold. When casting low-carbon steel for deep drawing, ingots weighing 6.5 tons before feeding steel to the bottom of the mold also place the briquette prepared from the slag-forming mixture on liquid glass and pressed to the appropriate section of the mold. The size of the silicobar ligature pieces is 40 mm. Briquette consumption - 4 kg / ton of steel. In the mold get the active liquid slag from the metal in the lower part of the briquette; The slag protects the metal surface from oxidation and is involved in the formation of a thin slag skull between the ingot body and the mold wall, ensuring an increase in the surface cleanliness of the finished ingot. As a result of steel casting under the briquettes made according to the method described, the percentage of yield of an ingot with a clean surface of the first category increased by 2%. Decreases by 0.5 / about the scrap of ingots, due to non-metallic inclusions due to the modification, they have become barium. When casting 20K steel on a semi-continuous machine, casting billets into ingots with a section of 370 x 370 mm at a drawing speed of 0.3 m / min. The slag-forming mixture in the form of granules 1.2 kg / ton of steel is fed to the metal mirror after filling the mold with 150 mm metal. . The sizes of the pieces of the silicobar ligature in the granules are 2.0 mm. Slag-metal granules as consumed in the mold evenly served throughout the casting. The use of slag-forming steel of the proposed composition increases the yield of ingots of steel prone to cracking and surface defects, for example, 20K steel and increases the durability of products, for example, rolling bearings made of ShH 15 steel by about 1.6 times. Claim I. Slag-forming mixture for steel casting, including aluminum powder, silicocalcium, manganese ore, fluorspar, silicate lump, water glass, characterized in that, in order to improve the quality of steel and increase the yield, it additionally contains silicobarium at the following the ratio of components, weight. % Aluminum powder4-8 Silicocalcium15-20 Manganese ore15-22 Fluorspar15-25 Liquid glass5-15 Silicobarium13-35 Silicate blockElite. 2. A mixture according to claim 1, characterized in that the size of the silicobar fractions is 2-4 mm. Sources of information taken into account during the examination 1. USSR author's certificate number 387780, cl. B 22 D 7/10, 1971. 2. USSR author's certificate JSfo 226653, cl. In 22 D 11/00, 1966.