Bloom ultrahigh-carbon wear-resistant ball steel continuous casting covering slag and preparation method thereof

Abstract

The invention discloses bloom ultrahigh-carbon wear-resistant ball steel continuous casting covering slag and a preparation method thereof, and belongs to the technical field of steelmaking metallurgy auxiliary materials. The high-temperature-resistant electric smelting material is prepared from the following raw materials in parts by weight: 15-28 parts of wollastonite powder, 20-40 parts of an electric smelting pre-melting material, 3-6 parts of lithium metaborate, 2-8 parts of boron glass, 2-4 parts of sodium fluoride, 5-13 parts of sodium carbonate, 2-7 parts of barium fluoride, 7-11 parts of fluorite powder, 2-5 parts of electrode graphite, 2-5 parts of high-carbon amorphous graphite, 2-4 parts of N660 carbon black and 2-4 parts of dextrin. According to the mode, the casting liquid has relatively low viscosity, relatively low melting point and relatively high alkalinity, the lubrication of a casting blank is improved, the capability of absorbing floating inclusions in molten steel is improved, the occurrence rate of cracks and bleed-out on the surface of the casting blank is reduced, the surface and subcutaneous quality of the casting blank is improved, and the production efficiency of continuous casting is improved; the casting powder is particularly suitable for continuous casting production of bloom ultrahigh-carbon wear-resistant ball steel.

Description

Technical Field

[0001] The invention relates to the technical field of steelmaking metallurgical auxiliary materials, in particular to a large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag and a preparation method thereof. Background Art

[0002] The higher the carbon content in the wear-resistant ball steel, the greater the hardness and the higher the wear resistance. However, as the carbon content in the steel increases during the continuous casting process, the casting temperature is greatly reduced. At the same time, the primary billet shell of high-carbon steel is high-temperature austenite, the billet shell has good plasticity, and the billet shell is easily attached to the crystallizer under the static pressure of the molten steel. The production and use of wear-resistant ball steel requires the use of protective slag, which forms a slag layer, a sintering layer, and a powder slag layer from bottom to top on the surface of the molten steel. It has the following functions: the powder slag layer has a heat preservation effect; the slag layer can isolate the air to prevent the oxidation of the molten steel; the slag absorbs and dissolves the floating inclusions in the molten steel.

[0003] The current protective slag has a high melting point, high viscosity, and low basicity. It has a weak ability to absorb floating inclusions in molten steel, and the incidence of cracks and steel leakage on the surface of the ingot is high, which reduces the surface and subsurface quality of the ingot and may even cause steel leakage accidents.

[0004] Therefore, a large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag and a preparation method thereof are proposed to solve the above problems. Summary of the invention

[0005] The object of the present invention is to provide a large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a large square billet ultra-high carbon wear-resistant ball steel continuous casting protective slag is prepared from the following raw materials in parts by weight: 15-28 parts of wollastonite powder, 20-40 parts of electric melting pre-melted material, 3-6 parts of lithium metaborate, 2-8 parts of borosilicate glass, 2-4 parts of sodium fluoride, 5-13 parts of soda ash, 2-7 parts of barium fluoride, 7-11 parts of fluorite powder, 2-5 parts of electrode graphite, 2-5 parts of high carbon earthy graphite, 2-4 parts of N660 carbon black, and 2-4 parts of dextrin.

[0007] Furthermore, the wollastonite powder, electric melting premelt, lithium boron metaborate, boron glass, barium fluoride, fluorite, electrode graphite, and high carbon earthy graphite are all 300 meshes.

[0008] Furthermore, the N660 carbon black is 500 mesh.

[0009] Furthermore, the composition of the electro-melted pre-melt is: CaO: 33.0-37.0%, SiO2: 38.0-42.0%, MgO: 1.0-2.0%, Fe2O3: 0.3-1.0%, Al2O3: 2.0-6.0%, Na2O: 8.0-12.0%, F-: 7.0-11.0%.

[0010] A method for preparing a large square billet ultra-high carbon wear-resistant ball steel continuous casting mold slag comprises the following steps:

[0011] (1) Weighing each raw material by weight, placing it in a pulping tank, adding water and stirring, controlling the slurry concentration to 0.65-0.70%, and preparing a mixed slurry; conveying the mixed slurry to a water mill for grinding, and pumping the ground slurry to the pulping tank during grinding for cyclic grinding;

[0012] (2) placing the slurry after circulating grinding into a low-level tank and pressurizing it into a spray drying tower for spray granulation;

[0013] (3) screening out particles with a particle size of 20-80 mesh to obtain large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag;

[0014] (4) Sampling and testing of chemical composition;

[0015] (5) Packaging and storage.

[0016] Furthermore, the basicity of the large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag is 0.65-0.85.

[0017] Furthermore, the melting point of the large square billet ultra-high carbon wear-resistant spheroidal steel continuous casting protection slag is 900-980°C.

[0018] Furthermore, the viscosity of the large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag is 0.10-0.20 Pa·s at 1300°C.

[0019] Furthermore, in the step (1), the stirring time is 15-30 minutes, and the circulating grinding time is 50-70 minutes.

[0020] Furthermore, in the step (2), the slurry is pressurized to 1.4-20Mpa, the aperture of the spray plate is 2.2mm, the temperature inside the spray drying tower is 450-550°C, the outlet temperature is 150-170°C, and the moisture content of the product is controlled at 0.15-0.30%.

[0021] The beneficial effects of the present invention are:

[0022] 1. The present invention should have relatively low viscosity, low melting point and high basicity, improve the lubrication of the ingot, enhance the ability to absorb floating inclusions in molten steel, reduce the incidence of cracks and steel leakage on the surface of the ingot, improve the surface and subcutaneous quality of the ingot, and improve the production efficiency of continuous casting. The protective slag is particularly suitable for the continuous casting production of large square billets with ultra-high carbon wear-resistant ball steel. DETAILED DESCRIPTION

[0023] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] The present invention will be further described below in conjunction with the embodiments.

[0025] Embodiment 1

[0026] A large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag is prepared from the following raw materials in parts by weight: 15 parts of wollastonite powder, 35 parts of electric melting pre-melted material, 5 parts of lithium metaborate, 8 parts of borosilicate glass, 2 parts of sodium fluoride, 7 parts of soda ash, 6 parts of barium fluoride, 10 parts of fluorite powder, 3.5 parts of electrode graphite, 2 parts of high carbon earthy graphite, 2 parts of N660 carbon black, and 4 parts of dextrin.

[0027] The wollastonite powder, electric melting premelt, lithium boron metaborate, boron glass, barium fluoride, fluorite, electrode graphite, and high carbon earthy graphite are all 300 meshes.

[0028] The N660 carbon black is 500 mesh.

[0029] The components of the electro-melting pre-melted material are: CaO: 33.0%, SiO2: 42.0%, MgO: 1.3%, Fe2O3: 0.8%, Al2O3: 4.0%, Na2O: 9.0%, and F-: 10.0%.

[0030] A method for preparing a large square billet ultra-high carbon wear-resistant ball steel continuous casting mold slag comprises the following steps:

[0031] (1) Weighing each raw material by weight, placing it in a slurry tank, adding water and stirring, controlling the slurry concentration to 0.65%, and preparing a mixed slurry; conveying the mixed slurry to a water mill for grinding, and pumping the ground slurry to the slurry tank during grinding for cyclic grinding;

[0032] (2) placing the slurry after circulating grinding into a low-level tank and pressurizing it into a spray drying tower for spray granulation;

[0033] (3) screening out particles with a particle size of 20 mesh to obtain large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag;

[0034] (4) Sampling and testing of chemical composition;

[0035] (5) Packaging and storage.

[0036] In the step (1), the stirring time is 27 minutes and the circulating grinding time is 55 minutes.

[0037] In the step (2), the slurry is pressurized to 1.4 MPa, the aperture of the spray plate is 2.2 mm, the temperature inside the spray drying tower is 480° C., the outlet temperature is 160° C., and the moisture content of the product is controlled at 0.15-0.30%.

[0038] The basicity of the large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag is 0.65.

[0039] The melting point of the large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag is 900°C.

[0040] The viscosity of the large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag is 0.10 Pa·s at 1300° C.

[0041] Embodiment 2

[0042] A large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag is prepared from the following raw materials in parts by weight: 17 parts of wollastonite powder, 20 parts of electric melting pre-melted material, 4 parts of lithium metaborate, 6 parts of borosilicate glass, 3.5 parts of sodium fluoride, 6 parts of soda ash, 5 parts of barium fluoride, 7 parts of fluorite powder, 4.5 parts of electrode graphite, 5 parts of high carbon earthy graphite, 4 parts of N660 carbon black, and 2 parts of dextrin.

[0043] The wollastonite powder, electric melting premelt, lithium boron metaborate, boron glass, barium fluoride, fluorite, electrode graphite, and high carbon earthy graphite are all 300 meshes.

[0044] The N660 carbon black is 500 mesh.

[0045] The components of the electro-melting pre-melted material are: CaO: 37.0%, SiO2: 38.0%, MgO: 1.6%, Fe2O3: 0.3%, Al2O3: 5.0%, Na2O: 12.0%, and F-: 11.0%.

[0046] A method for preparing a large square billet ultra-high carbon wear-resistant ball steel continuous casting mold slag comprises the following steps:

[0047] (1) Weighing each raw material by weight, placing it in a slurry tank, adding water and stirring, and controlling the slurry concentration to 0.66% to prepare a mixed slurry; conveying the mixed slurry to a water mill for grinding, and while grinding, pumping the ground slurry to the slurry tank for cyclic grinding;

[0048] (2) placing the slurry after circulating grinding into a low-level tank and pressurizing it into a spray drying tower for spray granulation;

[0049] (3) Screening out particles with a particle size of 40 mesh to obtain large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag;

[0050] (4) Sampling and testing of chemical composition;

[0051] (5) Packaging and storage.

[0052] In the step (1), the stirring time is 15 minutes and the circulating grinding time is 50 minutes.

[0053] In the step (2), the slurry is pressurized to 1.9 MPa, the aperture of the spray plate is 2.2 mm, the temperature inside the spray drying tower is 450° C., the outlet temperature is 150-170° C., and the moisture content of the product is controlled at 0.30%.

[0054] The basicity of the large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag is 0.85.

[0055] The melting point of the large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag is 980°C.

[0056] The viscosity of the large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag is 0.20 Pa·s at 1300° C.

[0057] Embodiment 3

[0058] A large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag is prepared from the following raw materials in parts by weight: 28 parts of wollastonite powder, 28 parts of electric melting pre-melted material, 3 parts of lithium metaborate, 5 parts of borosilicate glass, 3.2 parts of sodium fluoride, 5 parts of soda ash, 2 parts of barium fluoride, 8 parts of fluorite powder, 2 parts of electrode graphite, 3 parts of high carbon earthy graphite, 3.5 parts of N660 carbon black, and 3.5 parts of dextrin.

[0059] The wollastonite powder, electric melting premelt, lithium boron metaborate, boron glass, barium fluoride, fluorite, electrode graphite, and high carbon earthy graphite are all 300 meshes.

[0060] The N660 carbon black is 500 mesh.

[0061] The components of the electro-melting pre-melted material are: CaO: 35.0%, SiO2: 39.0%, MgO: 1.7%, Fe2O3: 1.0%, Al2O3: 3.0%, Na2O: 11.0%, and F-: 8.0%.

[0062] A method for preparing a large square billet ultra-high carbon wear-resistant ball steel continuous casting mold slag comprises the following steps:

[0063] (1) Weighing each raw material by weight, placing it in a slurry tank, adding water and stirring, controlling the slurry concentration to 0.68%, and preparing a mixed slurry; conveying the mixed slurry to a water mill for grinding, and pumping the ground slurry to the slurry tank during grinding for cyclic grinding;

[0064] (2) placing the slurry after circulating grinding into a low-level tank and pressurizing it into a spray drying tower for spray granulation;

[0065] (3) screening out particles with a particle size of 50 mesh to obtain large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag;

[0066] (4) Sampling and testing of chemical composition;

[0067] (5) Packaging and storage.

[0068] In the step (1), the stirring time is 30 minutes and the circulating grinding time is 65 minutes.

[0069] In the step (2), the slurry is pressurized to 20 MPa, the aperture of the spray plate is 2.2 mm, the temperature inside the spray drying tower is 550° C., the outlet temperature is 170° C., and the moisture content of the product is controlled at 0.18%.

[0070] The basicity of the large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag is 0.68.

[0071] The melting point of the large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag is 920°C.

[0072] The viscosity of the large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag is 0.13 Pa·s at 1300° C.

[0073] Embodiment 4

[0074] A large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag is prepared from the following raw materials in parts by weight: 23 parts of wollastonite powder, 24 parts of electric melting pre-melted material, 6 parts of lithium metaborate, 4 parts of borosilicate glass, 3.8 parts of sodium fluoride, 1.3 parts of soda ash, 7 parts of barium fluoride, 9 parts of fluorite powder, 5 parts of electrode graphite, 4 parts of high carbon earthy graphite, 3.5 parts of N660 carbon black, and 3.5 parts of dextrin.

[0075] The wollastonite powder, electric melting premelt, lithium boron metaborate, boron glass, barium fluoride, fluorite, electrode graphite, and high carbon earthy graphite are all 300 meshes.

[0076] The N660 carbon black is 500 mesh.

[0077] The components of the electro-melting pre-melted material are: CaO: 36.0%, SiO2: 40.0%, MgO: 1.0%, Fe2O3: 0.5%, Al2O3: 2.0%, Na2O: 10.0%, and F-: 7.0%.

[0078] A method for preparing a large square billet ultra-high carbon wear-resistant ball steel continuous casting mold slag comprises the following steps:

[0079] (1) Weighing each raw material by weight, placing it in a slurry tank, adding water and stirring, controlling the slurry concentration to 0.70%, and preparing a mixed slurry; conveying the mixed slurry to a water mill for grinding, and pumping the ground slurry to the slurry tank during grinding for cyclic grinding;

[0080] (2) placing the slurry after circulating grinding into a low-level tank and pressurizing it into a spray drying tower for spray granulation;

[0081] (3) Screening out particles with a particle size of 60 mesh to obtain large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag;

[0082] (4) Sampling and testing of chemical composition;

[0083] (5) Packaging and storage.

[0084] In the step (1), the stirring time is 18 minutes and the circulating grinding time is 70 minutes.

[0085] In the step (2), the slurry is pressurized to 1.6 MPa, the aperture of the spray plate is 2.2 mm, the temperature inside the spray drying tower is 520° C., the outlet temperature is 155° C., and the moisture content of the product is controlled at 0.22%.

[0086] The basicity of the large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag is 0.78.

[0087] The melting point of the large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag is 940°C.

[0088] The viscosity of the large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag is 0.18 Pa·s at 1300° C.

[0089] Embodiment 5

[0090] A large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag is prepared from the following raw materials in parts by weight: 19 parts of wollastonite powder, 40 parts of electric melting pre-melted material, 5 parts of lithium metaborate, 2 parts of borosilicate glass, 4 parts of sodium fluoride, 9 parts of soda ash, 4 parts of barium fluoride, 11 parts of fluorite powder, 4 parts of electrode graphite, 3 parts of high carbon earthy graphite, 2.5 parts of N660 carbon black, and 3 parts of dextrin.

[0091] The wollastonite powder, electric melting premelt, lithium boron metaborate, boron glass, barium fluoride, fluorite, electrode graphite, and high carbon earthy graphite are all 300 meshes.

[0092] The N660 carbon black is 500 mesh.

[0093] The components of the electro-melting pre-melted material are: CaO: 34.0%, SiO2: 41.0%, MgO: 2.0%, Fe2O3: 0.7%, Al2O3: 6.0%, Na2O: 8.0%, and F-: 9.0%.

[0094] A method for preparing a large square billet ultra-high carbon wear-resistant ball steel continuous casting mold slag comprises the following steps:

[0095] (1) Weighing each raw material by weight, placing it in a slurry tank, adding water and stirring, and controlling the slurry concentration to 0.69% to prepare a mixed slurry; conveying the mixed slurry to a water mill for grinding, and while grinding, pumping the ground slurry to the slurry tank for cyclic grinding;

[0096] (2) placing the slurry after circulating grinding into a low-level tank and pressurizing it into a spray drying tower for spray granulation;

[0097] (3) screening out particles with a particle size of 80 mesh to obtain large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag;

[0098] (4) Sampling and testing of chemical composition;

[0099] (5) Packaging and storage.

[0100] In the step (1), the stirring time is 24 minutes and the circulating grinding time is 60 minutes.

[0101] In the step (2), the slurry is pressurized to 1.7 MPa, the aperture of the spray plate is 2.2 mm, the temperature inside the spray drying tower is 470° C., the outlet temperature is 165° C., and the moisture content of the product is controlled at 0.26%.

[0102] The basicity of the large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag is 0.81.

[0103] The melting point of the large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag is 950°C.

[0104] The viscosity of the large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag at 1300° C. is 0.16 Pa·s.

[0105] The specific statistics are as follows:

[0106]

[0107]

[0108] The present invention should have relatively low viscosity, low melting point and high basicity, improve the lubrication of the ingot, enhance the ability to absorb floating inclusions in molten steel, reduce the incidence of cracks and steel leakage on the surface of the ingot, improve the surface and subcutaneous quality of the ingot, and improve the production efficiency of continuous casting. The protective slag is particularly suitable for the continuous casting production of large square billets with ultra-high carbon wear-resistant ball steel.

[0109] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0110] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag, characterized in that: The invention is prepared from the following raw materials in parts by weight: 15-28 parts of wollastonite powder, 20-40 parts of electromelted pre-melted material, 3-6 parts of lithium metaborate, 2-8 parts of borosilicate glass, 2-4 parts of sodium fluoride, 5-13 parts of soda ash, 2-7 parts of barium fluoride, 7-11 parts of fluorite powder, 2-5 parts of electrode graphite, 2-5 parts of high carbon earthy graphite, 2-4 parts of N660 carbon black and 2-4 parts of dextrin.

2. The large square billet ultra-high carbon wear-resistant ball steel continuous casting mold slag according to claim 1, characterized in that: The wollastonite powder, electric melting pre-melted material, lithium boron metaborate, boron glass, barium fluoride, fluorite, electrode graphite, and high carbon earthy graphite are all 300 meshes.

3. The large square billet ultra-high carbon wear-resistant ball steel continuous casting mold slag according to claim 2, characterized in that: The N660 carbon black is 500 mesh.

4. The large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag according to claim 3, characterized in that: The components of the electro-melting pre-melted material are: CaO: 33.0-37.0%, SiO2: 38.0-42.0%, MgO: 1.0-2.0%, Fe2O3: 0.3-1.0%, Al2O3: 2.0-6.0%, Na2O: 8.0-12.0%, and F-: 7.0-11.0%.

5. A method for preparing the continuous casting mold slag of ultra-high carbon wear-resistant ball steel for large square billets according to claim 4, characterized in that: The following steps are involved: (1) Weighing each raw material by weight, placing it in a pulping tank, adding water and stirring, controlling the slurry concentration to 0.65-0.70%, and preparing a mixed slurry; conveying the mixed slurry to a water mill for grinding, and pumping the ground slurry to the pulping tank during grinding for cyclic grinding; (2) placing the slurry after circulating grinding into a low-level tank and pressurizing it into a spray drying tower for spray granulation; (3) screening out particles with a particle size of 20-80 mesh to obtain large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag; (4) Sampling and testing of chemical composition; (5) Packaging and storage.

6. The ultra-high carbon wear-resistant ball steel continuous casting mold slag for blooms according to claim 5, characterized in that: The basicity of the large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag is 0.65-0.

85.

7. The large square billet ultra-high carbon wear-resistant ball steel continuous casting mold slag according to claim 6, characterized in that: The melting point of the large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag is 900-980°C.

8. The ultra-high carbon wear-resistant ball steel continuous casting mold slag for blooms according to claim 7, characterized in that: The viscosity of the large square billet ultra-high carbon wear-resistant ball steel continuous casting protection slag at 1300° C. is 0.10-0.20 Pa·s.

9. The large square billet ultra-high carbon wear-resistant ball steel continuous casting mold slag according to claim 8, characterized in that: In the step (1), the stirring time is 15-30 minutes, and the circulating grinding time is 50-70 minutes.

10. The method for preparing the continuous casting mold slag of ultra-high carbon wear-resistant ball steel for large square billets according to claim 9, characterized in that: In the step (2), the slurry is pressurized to 1.4-20 MPa, the aperture of the spray plate is 2.2 mm, the temperature inside the spray drying tower is 450-550° C., the outlet temperature is 150-170° C., and the moisture content of the product is controlled at 0.15-0.30%.

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