A high-oxygen continuous casting billet and its preparation method
Patent Information
- Application Number
- CN202311225235.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-21
- Publication Date
- 2026-09-01
- Estimated Expiration
- 2043-09-21
AI Technical Summary
[0004]本申请提供了一种高氧连铸坯及其制备方法，以解决现有高氧连铸坯增碳严重的技术问题
[0021]本申请实施例提供的该高氧连铸坯的制备方法，通过采用采用CO2代替Ar作为连铸过程中的气体介质，对钢包和中间包中钢液进行脱碳，减少铸坯中气孔的生成；控制大包转台软吹的CO2流量以保证脱碳效果，控制所述连铸过程中使用的耐材和渣料的材质以减少额外增加碳含量。综上，本申请内容解决了现有高氧连铸坯增碳严重的技术问题。
Smart Images
Figure CN117226058B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of steelmaking technology, and in particular to a high-oxygen continuous casting billet and its preparation method. Background Technology
[0002] High-oxygen steel is produced by adding alloys to molten high-oxygen steel to precipitate small, dispersed inclusions. High-oxygen products exhibit excellent resistance to blistering, pinholes, adhesion, and machinability. By spraying enamel onto the surface of high-oxygen steel and firing it at high temperatures, it can be used to manufacture enamel products such as water heater liners, rice cooker liners, frying pans, bathtubs, and heating furnaces. Enamel steel is widely used in household appliances and industrial applications.
[0003] However, in the actual continuous casting process, carbon gain is severe, and defects such as bubbles or pinholes often occur; large inclusions are difficult to remove; and the refractory material of high-oxygen steel is severely corroded, resulting in poor castability of high-oxygen steel. Summary of the Invention
[0004] This application provides a high-oxygen continuous casting billet and its preparation method to solve the technical problem of severe carbon increase in existing high-oxygen continuous casting billets.
[0005] In a first aspect, this application provides a method for preparing a high-oxygen continuous casting billet, the method comprising:
[0006] Obtain high-oxygen molten steel with the target chemical composition;
[0007] The high-oxygen steel liquid is continuously cast using CO2 gas, and the materials of the refractory materials and slag used in the continuous casting process are controlled to obtain a high-oxygen continuous casting billet; wherein, the continuous casting includes: soft blowing of the high-oxygen steel liquid on a ladle turntable, and controlling the CO2 flow rate of the soft blowing on the ladle turntable.
[0008] Optionally, the CO2 flow rate of the large package turntable soft blowing is 30-200 L / min.
[0009] Optionally, the soft blowing time of the large package turntable is ≥5 minutes.
[0010] Optionally, the refractory material and slag material are both low-carbon and / or carbon-free materials.
[0011] Optionally, the step of using CO2 gas to continuously cast the high-oxygen steel liquid and controlling the materials of the refractory and slag used in the continuous casting process to obtain a high-oxygen continuously cast billet includes:
[0012] The high-oxygen steel melt is continuously cast using CO2 gas, and the materials of the refractory and slag used in the continuous casting process, as well as the flow rates of the three CO2 gas streams, are controlled to obtain a high-oxygen continuously cast billet; wherein, the flow rates of the three CO2 gas streams include:
[0013] CO2 gas flow rate of stopper rod, CO2 gas flow rate of inlet, and CO2 gas flow rate between plates.
[0014] Optionally, the CO2 gas flow rate of the stopper rod is 0-3 L / min.
[0015] Optionally, the CO2 gas flow rate at the water inlet is 0-3 L / min.
[0016] Optionally, the CO2 gas flow rate between the plates is 0-6 L / min.
[0017] Optionally, the target chemical composition includes carbon and all oxygen; wherein,
[0018] The carbon content is less than 20 ppm, and the total oxygen content is greater than 200 ppm.
[0019] Secondly, this application provides a high-oxygen continuous casting billet, which is prepared by the method described in any embodiment of the first aspect.
[0020] The technical solutions provided in this application have the following advantages compared with the prior art:
[0021] The method for preparing a high-oxygen continuously cast billet provided in this application employs CO2 instead of Ar as the gas medium in the continuous casting process to decarburize the molten steel in the ladle and tundish, reducing the formation of porosity in the billet. The method also controls the CO2 flow rate of the ladle turntable soft blowing to ensure decarburization effectiveness and controls the materials used in the continuous casting process for refractory and slag to minimize additional carbon content. In summary, this application solves the technical problem of severe carbon increase in existing high-oxygen continuously cast billets. Attached Figure Description
[0022] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.
[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0024] Figure 1 This is a schematic flowchart illustrating a method for preparing a high-oxygen continuous casting billet, as provided in an embodiment of this application. Detailed Implementation
[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0026] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.
[0027] In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. Furthermore, in the description of this application, terms such as "comprising" and "including" mean "including but not limited to." In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be a single or multiple.
[0028] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.
[0029] Firstly, this application provides a method for preparing a high-oxygen continuous casting billet, please refer to [link to relevant documentation]. Figure 1 The method includes:
[0030] S1. Obtain high-oxygen molten steel with the target chemical composition;
[0031] In some embodiments, the target chemical component includes carbon and total oxygen; wherein the carbon content is less than 20 ppm and the total oxygen content is greater than 200 ppm.
[0032] In this embodiment, controlling the carbon content to be less than 20 ppm and the total oxygen content to be greater than 200 ppm has the following positive effects: ensuring product performance and preparing for subsequent continuous casting. Specifically, the carbon content can be 18 ppm, 16 ppm, 14 ppm, 12 ppm, 10 ppm, etc. The total oxygen content can be 180 ppm, 160 ppm, 140 ppm, 120 ppm, 100 ppm, etc. The step S1 above, obtaining high-oxygen steel liquid with the target chemical composition, involves primary refining and refining the molten iron. The refining includes: vacuum decarburization with RH and alloying.
[0033] S2. CO2 gas is used to continuously cast the high-oxygen steel liquid, and the materials of the refractory and slag used in the continuous casting process are controlled to obtain a high-oxygen continuous casting billet; wherein, the continuous casting includes: soft blowing of the high-oxygen steel liquid on a ladle turntable, and controlling the CO2 flow rate of the soft blowing on the ladle turntable.
[0034] In the embodiments of this application, the positive effects of using CO2 gas for continuous casting of the high-oxygen molten steel are as follows: CO2 is used instead of Ar as the gas medium in the continuous casting process to decarburize the molten steel in the ladle and tundish, thereby reducing the generation of porosity in the billet.
[0035] Specifically, the continuous casting of the high-oxygen steel liquid using CO2 gas includes: turntable soft blowing, ladle protection, and the use of CO2 as the gas medium in the three gas channels. Its positive effects are: CO2 bubbles can decarburize in the high-oxygen steel liquid, reducing the formation of porosity in the cast billet; the cooling effect of the reaction between CO2 and C reduces the local temperature of the refractory material, thus reducing high-temperature corrosion and improving the continuous casting performance of the high-oxygen steel; the reaction of one volume of CO2 with C to generate two volumes of CO improves the efficiency of removing large inclusions from the high-oxygen steel liquid, significantly improving the quality of the high-oxygen steel.
[0036] In some embodiments, the CO2 flow rate of the large-package turntable soft blowing is 30-200 L / min.
[0037] In this embodiment, the positive effects of soft blowing on high-oxygen molten steel using a ladle turntable are as follows: soft blowing promotes the flotation of large inclusions in the molten steel. The positive effects of controlling the CO2 flow rate of the soft blowing on the ladle turntable to 30-200 L / min are: simultaneously ensuring the removal of large inclusions and decarburization. If the CO2 flow rate of the soft blowing on the ladle turntable is too high, it will lead to poor removal of large inclusions to a certain extent, seriously affecting the hydrogen storage performance and surface quality of the high-oxygen steel; if the CO2 flow rate of the soft blowing on the ladle turntable is too low, it will lead to poor decarburization in the molten steel to a certain extent. Specifically, the CO2 flow rate of the soft blowing on the ladle turntable can be 30 L / min, 50 L / min, 100 L / min, 150 L / min, 200 L / min, etc.
[0038] In some embodiments, the soft blowing time of the large package turntable is ≥5 minutes.
[0039] In this embodiment, controlling the soft blowing time of the ladle turntable to ≥5 minutes has the positive effect of ensuring the removal of large inclusions in the high-oxygen molten steel. If the soft blowing time of the ladle turntable is too short, it will lead to poor removal of large inclusions in the high-oxygen molten steel to a certain extent. Specifically, the soft blowing time of the ladle turntable can be 5 minutes, 6 minutes, 7 minutes, 8 minutes, etc.
[0040] In some embodiments, the refractory material and slag material are both low-carbon and / or carbon-free materials.
[0041] In the embodiments of this application, the use of low-carbon and / or carbon-free materials for both the refractory materials and slag has the positive effect of reducing the additional carbon content introduced by the refractory materials and slag. The refractory materials are ladle lining bricks, ladle inlet nozzles, ladle outlet nozzles, ladle long nozzles, tundish linings, and submersible nozzles; the refractory materials have erosion resistance, and the slag consists of tundish covering agent, ladle modifier, and protective slag.
[0042] In some embodiments, the continuous casting of the high-oxygen steel liquid using CO2 gas, and the control of the materials of the refractory and slag used in the continuous casting process to obtain a high-oxygen continuous casting billet, includes:
[0043] The high-oxygen steel melt is continuously cast using CO2 gas, and the materials of the refractory and slag used in the continuous casting process, as well as the flow rates of the three CO2 gas streams, are controlled to obtain a high-oxygen continuously cast billet; wherein, the flow rates of the three CO2 gas streams include:
[0044] CO2 gas flow rate of stopper rod, CO2 gas flow rate of inlet, and CO2 gas flow rate between plates.
[0045] In some embodiments, the CO2 gas flow rate of the stopper is 0-3 L / min.
[0046] In some embodiments, the CO2 gas flow rate at the water inlet is 0-3 L / min.
[0047] In some embodiments, the CO2 gas flow rate between the plates is 0-6 L / min.
[0048] In this embodiment, controlling the CO2 gas flow rate of the stopper rod to 0-3 L / min, the CO2 gas flow rate of the inlet to 0-3 L / min, and the CO2 gas flow rate between the plates to 0-6 L / min has the following positive effects: reducing high-temperature corrosion of the refractory material and improving the continuous casting performance of high-oxygen steel. If the CO2 gas flow rates of these three channels are too high, it will cause severe corrosion of the refractory material to a certain extent, affecting the continuous casting performance of high-oxygen steel. Specifically, the CO2 flow rate of the stopper rod can be 3 L / min, 2 L / min, 1 L / min, etc., the CO2 flow rate of the inlet to 3 L / min, 2 L / min, 1 L / min, etc., and the CO2 flow rate between the plates can be 6 L / min, 4 L / min, 2 L / min, etc.
[0049] The method for preparing the high-oxygen continuous casting billet provided in this application makes full use of the endothermic reaction of CO2 and C and the increase in volume, which alleviates the carbon increase problem in the continuous casting process of high-oxygen steel. At the same time, it can reduce the high-temperature erosion of refractory materials, improve the continuous casting performance of high-oxygen steel and the efficiency of removing large inclusions, and significantly improve the quality of high-oxygen steel.
[0050] Secondly, this application provides a high-oxygen continuous casting billet, which is prepared by the method described in any embodiment of the first aspect.
[0051] The high-oxygen continuous casting billet is realized based on the above-described preparation method of the high-oxygen continuous casting billet. The specific steps of the preparation method of the high-oxygen continuous casting billet can be referred to the above embodiments. Since the high-oxygen continuous casting billet adopts some or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated here.
[0052] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional conditions, or conditions recommended by the manufacturer are followed.
[0053] This application provides a method for preparing a high-oxygen continuous casting billet, the method comprising:
[0054] S11. Obtain high-oxygen molten steel with the target chemical composition;
[0055] S21. The high-oxygen steel liquid is continuously cast using CO2 gas, and the materials of the refractory and slag used in the continuous casting process are controlled to obtain a high-oxygen continuously cast billet; wherein, the continuous casting includes: soft blowing of the high-oxygen steel liquid onto a ladle turntable, and controlling the CO2 flow rate of the soft blowing onto the ladle turntable. Specific process parameters are shown in Table 1, and continuous casting results are shown in Table 2.
[0056] Table 1. Preparation process parameters of high-oxygen continuous casting billets
[0057]
[0058]
[0059] Table 2 Continuous casting results of high-oxygen continuous casting billets
[0060] Example 1 qualified Example 2 qualified Example 3 qualified Comparative Example 1 Serious carbon increase Comparative Example 2 Serious carbon increase Comparative Example 3 Large temperature drop, poor removal of impurities Comparative Example 4 Poor removal of inclusions Comparative Example 5 Severe corrosion of refractory materials Comparative Example 6 Serious carbon increase
[0061] Based on the analysis in Tables 1-2 above:
[0062] In Examples 1-3, CO2 is used instead of Ar as the gas medium in the continuous casting process to decarburize the molten steel in the ladle and tundish, reducing the carbon gain from the end of RH to the tundish. The cooling effect of the reaction between CO2 and C reduces the local temperature of the refractory material, which can reduce the high-temperature corrosion of the refractory material and improve the continuous casting performance of high-oxygen steel. The reaction of one volume of CO2 blown in with C to generate two volumes of CO will improve the efficiency of removing large inclusions from the high-oxygen steel and significantly improve the quality of high-oxygen steel.
[0063] In Comparative Example 1, the turntable with soft blowing, large package protection, and argon as the gas medium in the three gas channels could not decarburize the high-oxygen steel liquid, resulting in severe carbonization of the high-oxygen steel.
[0064] In Comparative Example 2, the CO2 flow rate of the turntable with soft blowing is 10 L / min, which is outside the range of the embodiments of this application. The soft blowing flow rate is too small, and the high oxygen molten steel hardly decarburizes.
[0065] In Comparative Example 3, the CO2 flow rate of the turntable with soft blowing is 500 L / min, which is outside the range of the embodiments of this application. The soft blowing flow rate is too large, resulting in poor removal of large inclusions and a large temperature drop during soft blowing.
[0066] In Comparative Example 4, the soft blowing time on the turntable was 2 minutes. The soft blowing time was too short, resulting in poor removal of large inclusions in the high-oxygen molten steel.
[0067] In Comparative Example 5, the gas flow rate of the stopper rod was 5L / min, the gas flow rate of the inlet was 5L / min, and the gas flow rate between the plates was 9L / min. Excessive gas flow rates in all three channels would cause severe corrosion of the refractory material and affect the continuous casting performance of the high-oxygen steel.
[0068] In Comparative Example 6, the refractory and slag materials used in the continuous casting process were high-carbon materials, and the carbon content of the refractory and slag materials was severely increased during the continuous casting process of the high-oxygen molten steel.
[0069] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.
Claims
1. A method for preparing a high-oxygen continuous casting billet, characterized in that, The method includes: Obtain high-oxygen molten steel with a target chemical composition, wherein the target chemical composition includes carbon and total oxygen, wherein the carbon content is less than 20 ppm and the total oxygen content is greater than 200 ppm; The high-oxygen steel liquid is continuously cast using CO2 gas, and the materials of the refractory and slag used in the continuous casting process, as well as the flow rates of the three CO2 gas streams, are controlled to obtain a high-oxygen continuously cast billet. The continuous casting process includes: soft blowing of the high-oxygen steel liquid onto a ladle turntable, with the CO2 flow rate controlled at 30-200 L / min. The three CO2 gas flow rates are: 0-3 L / min for the stopper rod, 0-3 L / min for the inlet, and 0-6 L / min for the interplate. The refractory materials and slag materials are all made of low-carbon or carbon-free materials.
2. The method according to claim 1, characterized in that, The soft blowing time for the large package turntable is ≥5 minutes.
3. A high-oxygen continuous casting billet, characterized in that, The high-oxygen continuous casting billet is prepared by the method described in any one of claims 1-2.
Citation Information
Patent Citations
Production method of sulfur-containing ultrahigh-oxygen ultra-low carbon steel
CN112961958A