CN115229146A - Method for improving alkalinity of steel slag in tundish of continuous casting machine - Google Patents
Method for improving alkalinity of steel slag in tundish of continuous casting machine Download PDFInfo
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- CN115229146A CN115229146A CN202210944500.5A CN202210944500A CN115229146A CN 115229146 A CN115229146 A CN 115229146A CN 202210944500 A CN202210944500 A CN 202210944500A CN 115229146 A CN115229146 A CN 115229146A
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- tundish
- covering agent
- steel slag
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- steel
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
- B22D11/111—Treating the molten metal by using protecting powders
Abstract
The application provides a method for improving the alkalinity of steel slag in a tundish of a continuous casting machine, wherein an improved covering agent comprises the following components in percentage by mass: 20% -23% of SiO 2 25 to 28 percent of CaO,7 to 10 percent of Al 2 O 3 3% -6% of MgO and 18% -21% of C Fixing device 17% -21% of CaCO 3 The remainder being H 2 O; the method comprises the following steps of (1) eliminating the addition of carbonized rice hulls into a tundish, adding an improved covering agent onto the liquid level in the tundish, controlling the addition amount of the improved covering agent to be 0.20kg/t molten steel-0.40 kg/t molten steel, and controlling the alkalinity of steel slag to be 1.3-1.5; the improved covering agent has the functions of adsorbing impurities, preserving heat, preventing secondary oxidation and the like, so that the steel slag is alkaline, the corrosion of the original-acid steel slag to the dry material of the magnesium alkaline working layer is avoided, the alkalinity of the steel slag is improved to be suitable for the dry material of the magnesium alkaline working layer, the corrosion of the steel slag to the working layer is reduced, the service lives of the working layer and a tundish are prolonged, the casting blank quality of a continuous casting machine is improved, the production stability of the continuous casting machine is improved, and the corrosion of the novel covering agent to molten steel is reducedAnd (3) contamination.
Description
Technical Field
The invention relates to the technical field of tundish metallurgy, in particular to a method for improving the alkalinity of steel slag in a tundish of a continuous casting machine.
Background
The tundish in the continuous casting machine is an intermediate link of the steelmaking production flow, has the functions of storing steel, stabilizing flow, shunting, homogenizing temperature and removing inclusions, and is a joint point for changing the intermittent operation to the continuous operation of molten steel. The tundish is directly contacted with molten steel to form a working layer, the working layer has good high-temperature performance under high-temperature use conditions, high refractoriness and certain high-temperature strength are required, good chemical stability is required, secondary oxidation on the molten steel is avoided under the high-temperature condition, the molten steel is not polluted, the quality of steel billets is not affected, and the tundish has good molten slag corrosion and penetration resistance and molten steel and slag liquid scouring resistance in the use process.
In normal production, in order to prevent the molten steel in the tundish from being exposed and radiated and prevent the molten steel from being secondarily oxidized and absorb impurities in the molten steel, a certain amount of auxiliary materials are required to be added into the tundish in each furnace. The auxiliary materials added into the tundish are carbonized rice hulls and a common covering agent generally, in order to ensure the heat preservation effect of molten steel, the addition amount of the carbonized rice hulls is generally more than that of the common covering agent, and the carbonized rice hulls account for about 90% of the auxiliary materials in each furnace. The components of the carbonized rice husk are acidic, and the alkalinity of the steel slag in the tundish is about 0.9 due to the addition of the carbonized rice husk, so that the steel slag is acidic.
Because the working layer of the tundish in the current continuous casting machine generally adopts a magnesium dry material, and the dry material comprises an alkaline material. The acid steel slag in the tundish can erode the magnesium working layer of the tundish, so that the working layer of the tundish is peeled off, small particles form inclusion in molten steel, large particles are gathered, and when the acid steel slag passes through a water gap of the tundish along a molten steel flow field, the water gap is easily blocked to cause fluctuation of the liquid level of a crystallizer, so that the quality of a product is seriously influenced, the working layer of the tundish is not anti-eroded, the service life of the tundish is shortened, the use cost of refractory materials is increased, and casting blank loss caused by casting times is reduced.
Disclosure of Invention
The invention aims to provide a method for improving the alkalinity of steel slag in a tundish of a continuous casting machine, which improves the alkalinity of the steel slag in the tundish to show alkalinity, ensures that the alkalinity of the steel slag in the tundish is suitable for a magnesium alkaline working layer dry material, reduces the corrosion of the steel slag to the magnesium tundish working layer, prolongs the service life of the tundish working layer and reduces the inclusion content in molten steel.
In order to solve the technical problems, the technical scheme provided by the invention is as follows:
a method for improving the alkalinity of steel slag in a tundish of a continuous casting machine comprises the following steps:
the improved covering agent comprises the following components in percentage by mass:
20% -23% of SiO 2 25 to 28 percent of CaO,7 to 10 percent of Al 2 O 3 3% -6% of MgO and 18% -21% of C Fixing device 17% -21% of CaCO 3 The remainder being H 2 O；
The method is characterized in that carbonized rice hulls are not added into a tundish, an improved covering agent is added onto the liquid surface in the tundish, the adding amount of the improved covering agent is controlled to be 0.20kg/t molten steel-0.40 kg/t molten steel, and the alkalinity of steel slag in the tundish is controlled to be 1.3-1.5.
Preferably, the improved covering agent is prepared from the following raw materials in proportion:
28% -32% of pre-melting material, 23% -25% of carbon powder, 38% -42% of lime powder and/or limestone powder, 2% -6% of magnesium oxide powder and 1% -3% of adhesive;
the preparation method of the improved covering agent comprises the following steps: the raw materials are stirred and mixed evenly in a stirrer, and then are granulated to obtain the finished product of the improved covering agent.
Preferably, during the ladle changing process, the improved covering agent is not added, the improved covering agent is added into the tundish after the ladle changing is completed and the liquid level of the tundish is stable, and the position of a steel ladle pouring steel flow is avoided, so that the improved covering agent is prevented from being stirred into the molten steel.
Compared with the prior art, the invention has the following beneficial effects:
(1) The method combines the chemical characteristics of the magnesium dry material, adjusts the component proportion of the covering agent, increases the CaO content by 3 percent as a whole to 25 to 28 percent, adds MgO by 3 to 6 percent to make SiO 2 The content of the carbon dioxide accounts for 20-23 percent of the whole body, and carbon C is fixed Fixing device The content adjustment accounts for 18-21%, so that the novel tundish covering agent has the main functions of adsorbing impurities, preserving heat, preventing secondary oxidation and the like when the common covering agent and the carbonized rice husk are added into a tundish together.
(2) In the application, the acidic tundish steel slag is caused to be acidic by adding the carbonized rice hulls (acidic), usually about 0.9, the addition of a novel tundish covering agent is reduced or even removed, the basic components of the novel tundish covering agent cause the tundish steel slag to be alkaline, the corrosion of the acidic tundish steel slag to the dry magnesium alkaline working layer is avoided by sampling and checking more than 1.3, the alkalinity of the tundish steel slag is improved to be suitable for the dry magnesium alkaline working layer, and the corrosion of the steel slag to the tundish working layer is reduced.
(3) In the application, the tundish steel slag is alkaline, the corrosion to a dry material of a magnesium working layer is reduced, the knotting thickness of the working layer is 100-110mm, the residual thickness of the working layer of the tundish after 48 hours of use is increased from 40mm to 60mm, the tundish steel slag can be used for 24 hours after calculation, the service life of the working layer of the tundish is prolonged, and the service life of the tundish is prolonged.
(4) In the application, the service performance of the magnesium-based working layer dry material is effectively guaranteed, the quality problem caused by the fact that the dry material falling objects of the working layer enter molten steel after the working layer is corroded and the situation that the liquid level fluctuates due to the fact that a water gap of a tundish is blocked is reduced, the low-power inclusion rating of a casting blank is obviously reduced, the inclusion rating is reduced from 2.0-2.5 level to be less than or equal to 1.0 level, the liquid level fluctuation due to the fact that the water gap is blocked is reduced from 35 times per month to less than or equal to 7 times per month, the reduction amplitude of the water gap is up to 80% or more, the casting blank quality of a continuous casting machine is improved, and the production stability of the continuous casting machine is greatly stabilized.
(5) In the application, the adding time of the novel covering agent is reasonably regulated, and the pollution of the novel covering agent to molten steel is reduced.
To sum up, this application carries out the composition improvement to novel tundish covering agent through the characteristic that combines magnesium working layer dry-type material, through the addition of novel tundish covering agent with tundish acid slag adjustment for alkaline slag, has reduced the excessive erosion of slag to magnesium working layer dry-type material, in addition, has standardized the addition of novel tundish covering agent and has added the opportunity, easy operation easily trails, the implementation of being convenient for.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are a part of the embodiments of the present invention, but not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
The application provides a method for improving the alkalinity of steel slag in a tundish of a continuous casting machine, which comprises the following steps:
the improved covering agent comprises the following components in percentage by mass:
20% -23% of SiO 2 25 to 28 percent of CaO,7 to 10 percent of Al 2 O 3 3% -6% of MgO and 18% -21% of C Fixing device 17% -21% of CaCO 3 The remainder being H 2 O；
The method is characterized in that carbonized rice hulls are not added into a tundish, an improved covering agent is added onto the liquid surface in the tundish, the adding amount of the improved covering agent is controlled to be 0.20kg/t molten steel-0.40 kg/t molten steel, and the alkalinity of steel slag in the tundish is controlled to be 1.3-1.5.
In one embodiment of the present application, the improved covering agent is prepared from the following raw materials:
28% -32% of pre-melting material, 23% -25% of carbon powder, 38% -42% of lime powder and/or limestone powder, 2% -6% of magnesium oxide powder and 1% -3% of adhesive;
the preparation method of the improved covering agent comprises the following steps: the raw materials are stirred and mixed evenly in a stirrer, and then are granulated to obtain the finished product of the improved covering agent.
In one embodiment of the application, the improved covering agent is not added firstly in the ladle changing process, the improved covering agent is added into the tundish after the ladle changing is finished and the liquid level of the tundish is stable, and the position of the steel ladle for pouring a steel flow is avoided, so that the improved covering agent is prevented from being stirred into the molten steel.
In the application, 1) the novel tundish covering agent is proportioned according to the requirements of molten steel, wherein the addition of carbon powder can ensure the heat preservation performance of the covering agent, and the addition of the pre-melted material can effectively avoid the incrustation of steel slag on the surface of the molten steel, so that the novel tundish covering agent has the main functions of a common covering agent and carbonized rice husks;
2) In the casting process of molten steel, the adding amount of auxiliary materials in the tundish is adjusted: the addition of carbonized rice hulls is cancelled, and the addition amount of a novel tundish covering agent is increased;
3) Optimizing an adding mode, prohibiting adding of the novel tundish covering agent in the ladle changing process, and adding the novel tundish covering agent after the ladle changing is completed and the liquid level of the tundish is stable, and avoiding the position of a steel flow;
in conclusion, the novel tundish covering agent is effectively proportioned according to the requirement of molten steel, the molten steel surface steel slag in the tundish is adjusted to be alkaline by adjusting the adding amount of the novel tundish covering agent in the tundish, the excessive corrosion of the steel slag to a dry material of a magnesium working layer is reduced, and in addition, the pollution of auxiliary materials to the molten steel is further reduced by standardizing the adding time of the novel tundish covering agent.
In the application, (1) the component proportion of the covering agent is adjusted: the carbonized rice shell has low density, high carbon content, small slag heat conductivity coefficient, low melting speed, good heat preservation effect and low alkalinity;
the common covering agent can adsorb the impurities in the molten steel, but has poor heat-insulating property;
the chemical characteristics of the magnesium dry material are combined to adjust the component proportion of the covering agent, so that the novel tundish covering agent has the advantages of adsorption and inclusion of the common covering agent and the carbonized rice hulls, heat preservation, secondary oxidation prevention and the like;
(2) Adjusting the addition of the auxiliary materials, and adjusting the acid steel slag in the tundish to the alkaline steel slag: the addition of carbonized rice husks is cancelled, the addition amount of a novel tundish covering agent is increased, the covering agent is added from 1 bag of steel in each furnace to 4-6 bags of the novel covering agent added into molten steel in each furnace, the influence of acid materials on slag systems is avoided, meanwhile, steel slag is adjusted by adding alkaline materials, the alkalinity adapts to a magnesium dry material working layer, the corrosion to the working layer is reduced, stripped objects are reduced to enter molten steel, and the purity of the molten steel is improved;
(3) In the ladle changing process, the novel tundish covering agent is not added at first, and the novel tundish covering agent is added after the ladle changing is completed and the liquid level of the tundish is stable, so that the phenomenon that the novel tundish covering agent is stirred into molten steel to pollute the molten steel due to the fact that the liquid level is stirred is reduced.
In the application, the unit of element content, component content, proportion and proportion is mass percent.
Methods and devices not described in detail in the present invention are all the prior art and are not described in detail.
For further understanding of the present invention, the following examples are provided to illustrate the method for increasing the basicity of steel slag in a tundish of a continuous casting machine, and the scope of the present invention is not limited by the following examples.
Example 1
A method for improving the alkalinity of steel slag in a tundish of a continuous casting machine comprises the following steps:
the improved covering agent comprises the following components in percentage by mass:
21.6% SiO 2 26.7% of CaO,8.9% of Al 2 O 3 4.1% of MgO and 19.5% of C Fixing device 18.76% CaCO 3 0.44% of H 2 O；
The improved covering agent is prepared by mixing the following raw materials in proportion:
30% of pre-melting material, 24% of carbon powder, 25% of lime powder, 15% of limestone powder, 4% of magnesia powder and 2% of adhesive;
the preparation method of the improved covering agent comprises the following steps: uniformly stirring and mixing the raw materials in a stirrer, and then granulating to obtain the finished improved covering agent;
adding carbonized rice hulls into a tundish, adding an improved covering agent onto the liquid surface in the tundish, and controlling the adding amount of the improved covering agent to be 0.30kg/t molten steel;
in the ladle changing process, the improved covering agent is not added firstly, the improved covering agent is added into the tundish after the ladle changing is finished and the liquid level of the tundish is stable, the position of a steel ladle pouring steel flow is avoided, and the improved covering agent is prevented from being stirred into molten steel;
the results of comparative experiments on the effect of the improved coating agents are detailed in table 1.
TABLE 1 comparison of basicity of raw steel slag and improved steel slag
Before improvement, the total content of main alkaline oxides in the tundish steel slag is 42.45 percent, and the ratio of the main alkaline oxides to the acidic oxides is 0.93 percent; after improvement, the total content of main alkaline oxides in the tundish steel slag is 48.10 percent, and the ratio of the main alkaline oxides to the acidic oxide content is 35.01 percent and is 1.37;
the alkalinity of the tundish steel slag is improved from 0.93 to 1.37, so that the steel slag is alkaline, the physical and chemical characteristics of the magnesium alkaline tundish dry material are adapted, and the corrosion of the tundish steel slag to the magnesium tundish working layer dry material slag line is reduced.
The above description of the embodiments is only intended to facilitate the understanding of the method of the invention and its core idea. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.
Claims (3)
1. A method for improving the alkalinity of steel slag in a tundish of a continuous casting machine is characterized by comprising the following steps:
the improved covering agent comprises the following components in percentage by mass:
20% -23% of SiO 2 25 to 28 percent of CaO,7 to 10 percent of Al 2 O 3 3% -6% of MgO and 18% -21% of C Fixing device 17% -21% of CaCO 3 The remainder being H 2 O；
The method is characterized in that carbonized rice hulls are not added into a tundish, an improved covering agent is added onto the liquid surface in the tundish, the adding amount of the improved covering agent is controlled to be 0.20kg/t molten steel-0.40 kg/t molten steel, and the alkalinity of steel slag in the tundish is controlled to be 1.3-1.5.
2. The method for improving the alkalinity of the steel slag in the tundish of the continuous casting machine according to claim 1, wherein the improved covering agent is prepared from the following raw materials in parts by weight:
28% -32% of pre-melting material, 23% -25% of carbon powder, 38% -42% of lime powder and/or limestone powder, 2% -6% of magnesium oxide powder and 1% -3% of adhesive;
the preparation method of the improved covering agent comprises the following steps: the raw materials are stirred and mixed evenly in a stirrer, and then are granulated to obtain the finished product of the improved covering agent.
3. The method of claim 1, wherein the improved covering agent is not added during the ladle change, the improved covering agent is added into the tundish after the ladle change is completed and the liquid level of the tundish is stable, and the position of the steel ladle for pouring the steel flow is avoided, so that the improved covering agent is prevented from being stirred into the molten steel.
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| Application Number | Priority Date | Filing Date | Title |
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Citations (7)
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| KR20030011419A (en) * | 2001-08-02 | 2003-02-11 | 주식회사 포스코 | Tundish flux for stainless steel sheets having good inclusion absorptivity and low erosion of refractory |
| CN1778493A (en) * | 2004-11-18 | 2006-05-31 | 上海宝谊保温材料有限公司 | Cap agent with light alkaline particle steel coating |
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| CN102059329A (en) * | 2009-11-11 | 2011-05-18 | 杨忠鑫 | Tundish covering agent |
| CN102581240A (en) * | 2011-01-11 | 2012-07-18 | 宝山钢铁股份有限公司 | Tundish covering flux |
| CN102836979A (en) * | 2011-06-24 | 2012-12-26 | 中冶连铸技术工程股份有限公司 | Tundish covering agent |
| CN104226947A (en) * | 2013-06-17 | 2014-12-24 | 上海梅山钢铁股份有限公司 | Tundish covering agent for ultra-low-carbon steel |
-
2022
- 2022-08-08 CN CN202210944500.5A patent/CN115229146A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20030011419A (en) * | 2001-08-02 | 2003-02-11 | 주식회사 포스코 | Tundish flux for stainless steel sheets having good inclusion absorptivity and low erosion of refractory |
| CN1778493A (en) * | 2004-11-18 | 2006-05-31 | 上海宝谊保温材料有限公司 | Cap agent with light alkaline particle steel coating |
| CN101618442A (en) * | 2008-07-04 | 2010-01-06 | 上海梅山钢铁股份有限公司 | Reductive covering agent for continuous casting tundish |
| CN102059329A (en) * | 2009-11-11 | 2011-05-18 | 杨忠鑫 | Tundish covering agent |
| CN102581240A (en) * | 2011-01-11 | 2012-07-18 | 宝山钢铁股份有限公司 | Tundish covering flux |
| CN102836979A (en) * | 2011-06-24 | 2012-12-26 | 中冶连铸技术工程股份有限公司 | Tundish covering agent |
| CN104226947A (en) * | 2013-06-17 | 2014-12-24 | 上海梅山钢铁股份有限公司 | Tundish covering agent for ultra-low-carbon steel |
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