Barium-containing pre-melting material, casting powder and application thereof
By using barium-containing pre-melted material, the problems of uneven slag film and unstable heat transfer in high-speed continuous casting were solved, thereby improving the surface quality of the billet and production stability, and avoiding environmental pollution and equipment corrosion.
Patent Information
- Application Number
- CN202511555402.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-29
- Publication Date
- 2026-01-27
AI Technical Summary
Existing high-speed continuous casting protective slags are prone to uneven slag film thickness and unstable heat transfer during use, leading to surface cracks or steel leakage on the billet. Furthermore, fluxing materials containing boron or fluorite are prone to causing environmental pollution and equipment corrosion.
The material uses barium-containing pre-melted material with a chemical composition of 25%~35% SiO2, ≤4% MgO, 30%~37.5% CaO, ≤3% Fe2O3, 1.2%~3.0% Al2O3, 3.5%~6.4% Na2O, 7%~11.5% F- and 15.5%~23.2% BaO. It is heated and melted in an electric arc melting furnace and then naturally cooled. It is then ground until the passing rate of a 325-mesh sieve is ≥90%, forming a glassy phase and a fine microcrystalline structure, which replaces part of the barium carbonate and white alkali and fluorite flux.
It improves the stability and lubricity of the slag film, reduces surface defects of the billet, avoids the formation of white balls and slag streaks, reduces volatile matter, and ensures the stability and billet quality of high-speed continuous casting.
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of protecting slag, in particular to a barium-containing premelted material, a protecting slag and application thereof. BACKGROUND
[0002] With the development of high-speed casting, the protecting slag for continuous casting becomes an important factor, which not only affects the continuous casting, but also affects the surface quality of the final casting blank. Compared with the conventional protecting slag, the protecting slag for high-speed casting needs to have a low melting temperature and viscosity, and needs to ensure a good structure of the slag film to avoid a large number of melilite, nepheline or regular and uneven pores in the slag film, which affects the lubrication and heat transfer in the casting process, and finally affects the quality of the casting blank.
[0003] In the past, when adjusting the high-speed casting protecting slag, the focus is on adjusting the addition of fluxing agent materials such as fluorite, white alkali, borax, lithium carbonate and the like to reduce the melting temperature and viscosity of the protecting slag, reduce the crystallization rate, increase the glass state, thereby increasing the lubricity of the protecting slag, which is beneficial to the uniform heat transfer of the slag film, and is more beneficial to the lubrication of the protecting slag. However, borax containing boron is easy to produce white balls in the production process of the protecting slag. The production of white balls indicates that the distribution of borax in the protecting slag is very uneven. Excessive fluorite can cause the viscosity of the protecting slag to be too low, the slag film to be too thin, and the uniform and effective lubrication to be unable to be provided, which can easily cause the uneven thickness of the slag film and the instability of the heat transfer, resulting in surface cracks of the casting blank or sticking of the casting blank. In addition, fluorite contains F, which has a great influence on the corrosion of the continuous casting equipment and the environment. In addition to the extremely low melting point and viscosity of the protecting slag, excessive white alkali is also easy to cause the formation of crust or slag strips on the upper layer of the protecting slag during continuous casting. In addition to the harm caused by excessive fluorite, the phenomenon of slag inclusion in the continuous casting blank shell is significantly increased, and the phenomenon of leakage is also significantly increased.
[0004] To improve the stability of high-speed continuous casting, it is crucial to provide a stable premelted material base for the protecting slag.
[0005] Therefore, the present application is proposed. SUMMARY
[0006] One of the purposes of the present application is to provide a barium-containing premelted material to solve the technical problems in the prior art that the premelted material can cause the uneven thickness of the slag film and the instability of the heat transfer, resulting in surface cracks of the casting blank or sticking of the casting blank, or the formation of crust or slag strips on the upper layer of the protecting slag during continuous casting, or the phenomenon of slag inclusion in the continuous casting blank shell, and the phenomenon of leakage is significantly increased.
[0007] The second purpose of the present application is to provide a preparation method of the above-mentioned barium-containing premelted material.
[0008] The third purpose of the present application is to provide a protecting slag.
[0009] The fourth objective of this invention is to provide the application of the aforementioned protective slag in high-speed continuous casting.
[0010] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: In a first aspect, the present invention provides a barium-containing premelted material, the premelted material comprising the following chemical composition by mass percentage: 25%~35% SiO2, ≤4% MgO, 30%~37.5% CaO, ≤3% Fe2O3, 1.2%~3.0% Al2O3, 3.5%~6.4% Na2O, and 7%~11.5% F. - It contains 15.5% to 23.2% BaO, with the balance being unavoidable impurities.
[0011] Furthermore, the loss on ignition of the premelted material is <1.5%.
[0012] Furthermore, the melting temperature of the pre-melted material is 1150~1280℃.
[0013] Furthermore, the pre-melted material has a passing rate of ≥90% on a 325-mesh sieve.
[0014] Furthermore, the pre-melted material comprises the following raw materials in weight percentages: 25%~40% glass, 15%~30% limestone, 15%~25% fluorite and 20%~30% barite.
[0015] Secondly, the present invention provides a method for preparing the above-mentioned barium-containing premelted material, comprising mixing each raw material according to the formula amount, heating until completely melted, stirring evenly and cooling to obtain the barium-containing premelted material.
[0016] Furthermore, the particle size of the raw material is 3~50mm.
[0017] Furthermore, cooling also includes crushing and grinding; Preferably, the particle size after crushing is ≤50mm; Preferably, the grinding includes grinding to a passing rate of ≥90% through a 325-mesh sieve; Preferably, heating to complete melting includes heating to complete melting in an electric arc melting furnace; Preferably, the cooling includes natural cooling; Preferably, the natural cooling includes natural cooling within a high-temperature resistant pool.
[0018] Thirdly, the present invention provides a protective slag, comprising the above-mentioned barium-containing premelted material, or the barium-containing premelted material prepared by the above-mentioned preparation method.
[0019] Fourthly, the present invention provides the application of the above-mentioned protective slag in high-speed continuous casting; Preferably, the high-speed continuous casting includes stainless steel continuous casting and / or high-alloy steel continuous casting.
[0020] This invention provides a barium-containing premelted material with a high BaO content, exceeding 10%. Since BaO has a lower melting point than CaO, and BaO combines with SiO2 to form BaSiO3, a glassy phase with suitable melting point and viscosity is formed. This glassy phase facilitates uniform lubrication and adsorption of inclusions, reducing casting defects. Furthermore, it contains Na2O and F. - This reduces the amount of other expensive fluxes required in the protective slag; it contains no volatile carbonate components, preventing the decomposition of the protective slag during casting and the release of excessive CO2 gas. It also reduces the porosity and coarseness of the formed slag film, effectively enhancing heat transfer and lubrication, thus ensuring the produced billet surface is free of cracks, depressions, and other surface quality defects. Furthermore, it prevents adhesion during casting. Compared to boron-containing pre-melted materials, it avoids the formation of white spheres, increases the protective slag yield per unit time, and ensures smooth operation of the protective slag production process. Detailed Implementation
[0021] Unless otherwise defined herein, the scientific and technical terms used in conjunction with this invention shall have the meanings commonly understood by one of ordinary skill in the art. The meaning and scope of terms shall be clear; however, in any case of potential ambiguity, the definitions provided herein shall prevail over any dictionary or foreign definitions. In this application, unless otherwise stated, the use of "or" means "and / or". Furthermore, the use of the term "comprising" and other forms is non-limiting.
[0022] Unless otherwise stated, the methods and techniques of the present invention are generally carried out according to conventional methods well known in the art and as described in various general and more specific references, which are cited and discussed throughout this specification.
[0023] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0024] This invention provides a barium-containing premelted material, wherein the premelted material comprises the following chemical composition by mass percentage: 25%~35% SiO2, ≤4% MgO, 30%~37.5% CaO, ≤3% Fe2O3, 1.2%~3.0% Al2O3, 3.5%~6.4% Na2O, and 7%~11.5% F. - It contains 15.5% to 23.2% BaO, with the balance being unavoidable impurities.
[0025] This pre-melted material has a high BaO content, exceeding 10%. Since BaO's melting point is lower than CaO's, and BaO combines with SiO2 to form BaSiO3, creating a glassy melt and a small amount of fine microcrystalline structure, the glassy phase promotes uniform lubrication and reduces casting defects. It also contains Na2O and F. - This reduces the amount of other expensive fluxes required in the protective slag; it contains no volatile carbonate components, preventing the decomposition of the protective slag during casting and the release of excessive CO2 gas. It also reduces the porosity and coarseness of the formed slag film, effectively enhancing heat transfer and lubrication, thus ensuring the produced billet surface is free of cracks, depressions, and other surface quality defects. Furthermore, it prevents adhesion during casting. Compared to boron-containing pre-melted materials, it avoids the formation of white spheres, increases the protective slag yield per unit time, and ensures smooth operation of the protective slag production process.
[0026] The mass percentage of SiO2 can be, but is not limited to, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, or 35%, or any value between 25% and 35%.
[0027] The mass percentage of MgO can be, but is not limited to, 0.5%, 0.8%, 1%, 1.1%, 1.5%, 2%, 2.5%, 3%, 3.5% or 4%, or any value ≤4%.
[0028] The mass percentage of CaO can be, but is not limited to, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, or 37.5%, or any value between 30% and 37.5%.
[0029] The mass percentage of Fe2O3 can be, but is not limited to, 0.3%, 0.4%, 0.5%, 0.6%, 1%, 1.5%, 2%, 2.5%, or 3%, or any value ≤3%.
[0030] The mass percentage of Al2O3 can be, but is not limited to, 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.5%, 2.7% or 3%, or any value between 1.2% and 3.0%.
[0031] The mass percentage of Na2O can be, but is not limited to, 3.5%, 3.8%, 4%, 4.5%, 5%, 5.5%, 6%, 6.2%, or 6.4%, or any value between 3.5% and 6.4%.
[0032] F -The mass percentage can be, but is not limited to, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, or 11.5%, or any value between 7% and 11.5%.
[0033] The mass percentage of BaO can be, but is not limited to, 15.5%, 16%, 16.5%, 17%, 17.5%, 18%, 18.5%, 19%, 19.5%, 20%, 20.5%, 21%, 21.5%, 22%, 22.5%, or 23.2%, or any value between 15.5% and 23.2%.
[0034] In some specific embodiments, the loss on ignition of the premelted material is <1.5%. In some specific embodiments, the melting temperature of the premelted material is 1150~1280℃.
[0035] In some specific embodiments, the premelted material has a passing rate of ≥90% on a 325-mesh sieve.
[0036] In some specific embodiments, the premelted material comprises the following raw materials in weight percentages: 25% to 40% glass, 15% to 30% limestone, 15% to 25% fluorite, and 20% to 30% barite.
[0037] According to another aspect of the present invention, a method for preparing the above-mentioned barium-containing premelted material is also provided, comprising mixing the raw materials according to the formula amount, heating until completely melted, stirring evenly and cooling to obtain the barium-containing premelted material. This preparation method is simple, ensures uniform mixing of raw materials, and guarantees the uniformity of the premelted material composition.
[0038] In some specific embodiments, the mixed material can be placed in an electric arc melting furnace and heated until it is completely melted and stirred evenly, then flowed out of the furnace outlet for cooling. In some specific embodiments, the cooling includes natural cooling; in some specific embodiments, the natural cooling includes natural cooling in a high-temperature resistant tank.
[0039] In some specific embodiments, the particle size of the raw material is 3~50mm.
[0040] In some specific embodiments, the cooling process further includes crushing and grinding; in some specific embodiments, the particle size after crushing is ≤50mm; in some specific embodiments, the grinding includes grinding to a 325-mesh sieve with a pass rate ≥90%.
[0041] According to another aspect of the present invention, a protective slag is also provided, comprising the above-described barium-containing premelted material, or the barium-containing premelted material prepared by the above-described preparation method.
[0042] By replacing a certain proportion of barium carbonate, alkali, and fluorite flux in the existing formula with the aforementioned barium-containing pre-melted material, the high amount of barium carbonate and alkali in the protective slag can be avoided, thus reducing the volatile matter content of the protective slag. The low volatile matter content allows the protective slag to form a more stable slag film, reducing the formation of bubbles and non-metallic inclusions in the slag film, reducing defects such as slag streaks and crusts in the continuous casting process, and reducing the porosity and coarse grains of the slag film that occur during high casting speeds and the casting of stainless steel and high alloy steel. It can effectively play a role in heat transfer and lubrication, thereby ensuring that the surface of the produced billet is free of surface quality defects such as cracks and depressions, and also preventing adhesion during the casting process.
[0043] According to another aspect of the invention, the application of the above-described protective slag in high-speed continuous casting is also provided.
[0044] In some specific embodiments, the high-speed continuous casting includes stainless steel continuous casting and / or high-alloy steel continuous casting, with a casting speed ≥ 1.2 m / min.
[0045] The present invention will be further illustrated by the following examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or purchased directly from the market.
[0046] Example 1 S1: Weigh glass, limestone, fluorite, and barite with a particle size of 3~50mm at 40%, 20%, 20%, and 20% respectively by weight, dry mix and stir for 30 minutes, then put them into an electric arc melting furnace and heat until they are completely melted and stirred evenly. S2: Open the bottom discharge port of the electric arc melting furnace, let the completely melted and evenly stirred material flow into the high temperature resistant pool for natural cooling and then crush it, with a particle size ≤50mm; S3: The crushed material is fed into a Raymond mill and ground until the passing rate of a 325-mesh sieve is ≥90%, thus obtaining a barium-containing pre-melted material. X-ray fluorescence spectrometry analysis shows its chemical composition (wt%) as follows: SiO2: 35%, MgO: 0.95%, CaO: 30%, Fe2O3: 0.48%, Al2O3: 1.81%, Na2O: 6.1%, F... - : 9.87%, BaO: 15.5%, with the balance being other trace impurities.
[0047] The barium-containing premelted material prepared in this embodiment has a melting temperature of 1195℃ and a loss on ignition of 0.97%. SEM and XRD analysis showed that it contains a glassy melt with a small amount of fine microcrystalline structure.
[0048] This pre-melted material was used in the protective slag of continuous casting of Q460GJBZ25-3NT steel in a steel plant. The pre-melted material accounted for 40% of the total material by weight, and the production cross-section was 250*2260mm.2 Casting speed 1.15m / min. Usage description: The protective slag reacts well on the surface of the crystallizer during use, with no clumping, slow slag bar formation, liquid slag layer of 10-13mm, slag consumption of 0.58kg / t, and the surface of the produced billet is free of defects.
[0049] Example 2: S1: Weigh glass, limestone, fluorite, and barite with a particle size of 3~50mm at a weight percentage of 35%, 20%, 15%, and 30%, respectively. Dry mix and stir for 30 minutes, then put them into an electric arc melting furnace and heat until they are completely melted and stirred evenly. S2: Open the bottom discharge port of the electric arc melting furnace, and let the completely melted and evenly stirred material flow into the high temperature resistant pool for natural cooling and crushing. The particle size is ≤50mm. S3: The crushed material is fed into a Raymond mill and ground until the passing rate of a 325-mesh sieve is ≥90%, thus obtaining a barium-containing pre-melted material. X-ray fluorescence spectrometry analysis shows its chemical composition (wt%) as follows: SiO2: 25.5%, MgO: 0.85%, CaO: 36.5%, Fe2O3: 0.42%, Al2O3: 1.62%, Na2O: 4.7%, F... - 7.4% BaO: 22.6%, with the balance being other trace impurities.
[0050] The barium-containing premelted material prepared in this embodiment has a melting temperature of 1162℃ and a loss on ignition of 1.23%. Through SEM and XRD analysis, it was found that the internal crystal structure has few crystal precipitation and contains beneficial fluorinated phlogopite structures.
[0051] This pre-melted material was used in the protective slag of continuous casting of grade 321 steel in a steel plant. The pre-melted material accounted for 34% of the total weight, and the production cross-section was 200*1530mm. 2 The casting speed is 1.3~1.45m / min. Usage description: During use, the liquid slag inside the crystallizer is 11~13mm, the slag consumption is 0.51kg / t, there are no abnormalities inside the crystallizer, and there are no defects in hot rolling, which meets the requirements of the steel plant.
[0052] Example 3: S1: Weigh glass, limestone, fluorite, and barite with a particle size of 3~50mm at weight percentages of 28%, 30%, 17%, and 25%, respectively. After dry mixing for 30 minutes, load them into an electric arc melting furnace and heat until they are completely melted and stirred evenly. S2: Open the bottom discharge port of the electric arc melting furnace, and let the completely melted and evenly stirred material flow into the high temperature resistant pool for natural cooling and crushing. The particle size is ≤50mm. S3: The crushed material is fed into a Raymond mill and ground until the passing rate of a 325-mesh sieve is ≥90%, thus obtaining a barium-containing pre-melted material. X-ray fluorescence spectrometry analysis shows its chemical composition (wt%) as follows: SiO2: 34.6%, MgO: 0.77%, CaO: 31.2%, Fe2O3: 0.39%, Al2O3: 2.2%, Na2O: 4.6%, F... - 8.4% BaO: 17.2%, with the remainder being other trace impurities.
[0053] The barium-containing premelted material prepared in this embodiment has a melting temperature of 1248℃ and a loss on ignition of 0.71%. SEM and XRD analysis showed that the internal crystal structure was free of pores and had a uniform crystal phase.
[0054] This pre-melted material was used in the protective slag of continuous casting of 200 series high-manganese stainless steel (22% manganese content) in a steel plant. The weight ratio of this pre-melted material was 38%, and the production cross-section was 160*610mm. 2 Casting speed 1.4~1.6m / min, usage description: liquid slag layer thickness in the crystallizer is 15~18mm, slag consumption is 0.4~0.45kg / t, slag strips are not easy to form, there are no bubbles on the liquid surface of the crystallizer, the heat flow is stable, the hot inspection of the billet is normal, there is no scabbing phenomenon, and the rolled steel plate does not have black bands or inclusion defects.
[0055] Example 4: S1: Weigh glass, limestone, fluorite, and barite with a particle size of 3-50mm at 32%, 18%, 23%, and 27% by weight, respectively. After dry mixing for 30 minutes, load them into an electric arc melting furnace and heat until they are completely melted and stirred evenly. S2: Open the bottom discharge port of the electric arc melting furnace, and let the completely melted and evenly stirred material flow into the high temperature resistant pool for natural cooling and crushing. The particle size is ≤50mm. S3: The crushed material is fed into a Raymond mill and ground until the passing rate of a 325-mesh sieve is ≥90%, thus obtaining a barium-containing pre-melted material. X-ray fluorescence spectrometry analysis shows its chemical composition (wt%) as follows: SiO2: 28.0%, MgO: 1.1%, CaO: 30.2%, Fe2O3: 0.56%, Al2O3: 2.7%, Na2O: 5.2%, F... - 11.3% BaO: 20.7%, with the remainder being other trace impurities.
[0056] The barium-containing premelted material prepared in this embodiment has a melting temperature of 1215℃ and a loss on ignition of 0.58%. SEM and XRD analysis showed that the internal crystals are small and uniform.
[0057] This pre-melted material is used in the protective slag of ZGMn13 high-manganese wear-resistant steel continuous casting in a steel plant. The pre-melted material accounts for 35% of the total material by weight, and the production cross-section is 230*1500mm. 2 The casting speed was 1.4 m / min. Usage description: During the test, the flame in the crystallizer was moderate, the slag bar condition was normal, the consumption was 0.40-0.45 kg / t (within the required test range of 0.38-0.55 kg / t), the liquid-slag layer was 11-14 mm, and the heat flux density curve was relatively stable with fluctuations ≤0.2 MW / m. 2 No steel leakage alarms occurred, and no production or quality accidents took place. The billet surface was smooth, the iron oxide scale was uniform, the vibration mark depth was appropriate, and no defects such as slag pits, longitudinal cracks, or transverse cracks were observed.
[0058] Comparative Example 1 S1: Weigh glass, limestone, fluorite, and barite with a particle size of 3~50mm at weight percentages of 23%, 12%, 10%, and 55%, respectively. After dry mixing for 30 minutes, load them into an electric arc melting furnace and heat until they are completely melted and stirred evenly. S2: Open the bottom discharge port of the electric arc melting furnace, let the completely melted and evenly stirred material flow into the high temperature resistant pool for natural cooling and then crush it, with a particle size ≤50mm; S3: The crushed material is fed into a Raymond mill and ground until the passing rate of a 325-mesh sieve is ≥90%, thus obtaining a barium-containing pre-melted material. X-ray fluorescence spectrometry analysis shows its chemical composition (wt%) as follows: SiO2: 20.1%, MgO: 0.55%, CaO: 22.84%, Fe2O3: 0.33%, Al2O3: 1.04%, Na2O: 3.76%, F... - 4.94%, BaO: 31.47%, with the balance being other trace impurities.
[0059] The barium-containing premelted material prepared in this comparative example had a melting temperature of 1152℃ and a loss on ignition of 0.63%. SEM and XRD analysis showed that it contained a large amount of glassy molten material.
[0060] This pre-melted material, used in the continuous casting of 3Cr13 steel in a steel plant, has a weight ratio of 48%. Because the barium-containing pre-melted material has a high BaO content and low loss on ignition, it is not necessary to add excessive amounts of other fluxing agents while ensuring the melting temperature and viscosity of the corresponding protective slag. Therefore, the overall loss on ignition of the produced protective slag is low. Thus, it is suitable for production sections of 250*1650mm. 2During the casting speed of 1.0 m / min: the protective slag did not produce too many bubbles in the reaction on the surface of the crystallizer, which caused problems such as agglomeration and rapid slag strip formation. However, due to the high BaO content, the overall melting temperature of the protective slag was low, resulting in an excessively thick liquid slag layer (20-25 mm). For stainless steel casting, although it can avoid the entrapment of the carbon-rich layer, it is extremely unfavorable for the observation of the liquid surface and is prone to safety accidents. In addition, the final cast billet also has surface crack defects.
[0061] Comparative Example 2 S1: Weigh glass, limestone, fluorite, and barite with a particle size of 3~50mm at a weight percentage of 37%, 31%, 18%, and 14%, respectively. After dry mixing for 30 minutes, load them into an electric arc melting furnace and heat until they are completely melted and stirred evenly. S2: Open the bottom discharge port of the electric arc melting furnace, let the completely melted and evenly stirred material flow into the high temperature resistant pool for natural cooling and then crush it, with a particle size ≤50mm; S3: The crushed material is fed into a Raymond mill and ground until the passing rate of a 325-mesh sieve is ≥90%, thus obtaining a barium-containing pre-melted material. X-ray fluorescence spectrometry analysis shows its chemical composition (wt%) as follows: SiO2: 32.73%, MgO: 0.96%, CaO: 38.4%, Fe2O3: 0.47%, Al2O3: 1.75%, Na2O: 6.05%, F... - 8.89% BaO: 7.75%, with the balance being other trace impurities.
[0062] The barium-containing premelted material prepared in this comparative example had a melting temperature of 1285℃ and a loss on ignition of 0.51%. SEM and XRD analysis showed that the internal glass phase was relatively small, while the crystal structure was obvious.
[0063] This protective slag, used in the continuous casting of 3Cr13 steel at a steel plant, has a pre-melted material weight ratio of 50%. Because the BaO content in the barium-containing pre-melted material is low, to ensure the required melting temperature and viscosity of the protective slag, a large amount of other fluxing agents must be added. This not only easily leads to high overall product burn-off but also causes severe segregation of the protective slag during use. Application results show that during production of a 230*1600mm² cross-section at a casting speed of 1.0m / min: the protective slag reacts with numerous bubbles on the surface of the crystallizer, easily forming slag streaks at the edges of the crystallizer. These slag streaks form rapidly, have coarse grains, and significantly increase defects such as scale and scratches on the edges of the continuously cast billet. The measured slag layer thickness is 8-11mm, and the slag consumption is 0.35kg / t, which is lower than the required slag layer thickness of 16-20mm and slag consumption of more than 0.38kg / t for stainless steel continuous casting.
[0064] As the base material for protective slag, the purpose of pre-melting is to transform materials with significant differences in physical properties (such as density and melting temperature) into homogeneous materials with consistent chemical composition and mineral phase through pre-melting. This facilitates fusion, so the CaO and SiO2 content in the pre-melted material will not be too high or too low. Too high or too low content will not facilitate the melting of the pre-melted material and will increase the difficulty of subsequent batching of protective slag and the timeliness of fusion during continuous casting. Barium-containing pre-melted material is made by adding barium-containing raw materials to conventional pre-melted material. Barium ions can destroy the Si-O bond structure, destroy the long-range Si-O bond, and the microcrystalline glass structure of BaSiO3 in the short-range, thus increasing the glassy properties of the protective slag.
[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A barium-containing premelted material, characterized in that, The premelted material comprises the following chemical composition by mass percentage: 25%~35% SiO2, ≤4% MgO, 30%~37.5% CaO, ≤3% Fe2O3, 1.2%~3.0% Al2O3, 3.5%~6.4% Na2O, and 7%~11.5% F. - It contains 15.5% to 23.2% BaO, with the balance being unavoidable impurities.
2. The barium-containing premelted material according to claim 1, characterized in that, The loss on ignition of the premelted material is <1.5%.
3. The barium-containing premelted material according to claim 1, characterized in that, The melting temperature of the pre-melted material is 1150~1280℃.
4. The barium-containing premelted material according to claim 1, characterized in that, The pre-melted material has a passing rate of ≥90% on a 325-mesh sieve.
5. The barium-containing premelted material according to any one of claims 1 to 4, characterized in that, The pre-melted material comprises the following raw materials in weight percentages: 25%~40% glass, 15%~30% limestone, 15%~25% fluorite and 20%~30% barite.
6. The method for preparing the barium-containing premelted material according to any one of claims 1 to 5, characterized in that, This includes mixing the raw materials according to the formula, heating until completely melted, stirring evenly, and cooling to obtain a barium-containing pre-melted material.
7. The preparation method according to claim 6, characterized in that, The particle size of the raw material is 3~50mm.
8. The preparation method according to claim 7, characterized in that, After cooling, the process also includes crushing and grinding; Preferably, the particle size after crushing is ≤50mm; Preferably, the grinding includes grinding to a passing rate of ≥90% through a 325-mesh sieve; Preferably, heating to complete melting includes heating to complete melting in an electric arc melting furnace; Preferably, the cooling includes natural cooling; Preferably, the natural cooling includes natural cooling within a high-temperature resistant pool.
9. A protective slag, characterized in that, Includes the barium-containing premelted material according to any one of claims 1 to 5, or the barium-containing premelted material prepared by the preparation method according to any one of claims 6 to 8.
10. The application of the protective slag as described in claim 9 in high-speed continuous casting; Preferably, the high-speed continuous casting includes stainless steel continuous casting and / or high-alloy steel continuous casting.