Small slab continuous casting optimization method
By adopting composite deoxidation method during the continuous casting of small slabs and selecting appropriate protective slag according to the steel grade, the problem of leakage steel and poor quality of steel billets is solved, and efficient, low-cost and high-quality continuous casting production is achieved.
Patent Information
- Application Number
- CN202510102940.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-22
- Publication Date
- 2025-05-06
AI Technical Summary
During continuous casting of small slabs, steel leakage and poor quality of steel billets are prone to occur.
The composite deoxidation method is adopted to deoxidize the deoxidant, a mixture of aluminum blocks and silicon-aluminum calcium in the deoxidation stage of the molten steel, and the properties of the protective slag are determined according to different steel types to improve the deoxidation effect and the quality of the casting billet.
Through composite deoxygenation and reasonable selection of protective slag, steel leakage accidents are significantly reduced, the number of continuous casting furnaces is increased, and the quality of the casting billet is ensured, avoiding defects such as bubbles, slag inclusions and cracks.
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of steel plate processing, in particular to a small slab continuous casting optimization method. Background Art
[0002] With the development of the times, the production of steel will enter the era of plate production. The production efficiency, production cost and casting quality of small slab continuous casting machines are the key. Therefore, how to achieve high-efficiency, low-cost and high-quality production of small slab continuous casting machines is of great significance.
[0003] During the production process of the small slab continuous casting machine, it is easy to have frequent steel leakage, low number of continuous casting furnaces, and defects such as subcutaneous bubbles, center looseness, and surface cracks in the continuous casting process. Targeted process optimization and improvement must be carried out.
[0004] According to market demand, the steel types with large demand at present include Q195, Q235, Q355, etc. Among them, Q195 is a low-carbon and low-silicon steel. In order to ensure the deoxidation degree, metal aluminum is used for enhanced deoxidation. When aluminum strong deoxidation is used, if the protection measures against oxidation of molten steel are insufficient or improper, aluminum will be oxidized to form high-melting point Al2O3 inclusions during pouring; Q355 is a manganese-containing high-strength steel. In order to ensure the strength index, titanium elements need to be added for strengthening. Titanium is an element with strong affinity for oxygen. When the deoxidation degree is not good, titanium is easily oxidized to form high-melting point TiO2; but if the deoxidation degree is too good. Titanium carbonitride is easily formed, which is also a high-melting point precipitate. Whether it is Al2O3, TiO2 or Ti (CN), they are all high-melting point substances, which will affect the pouring characteristics of molten steel and even affect the quality of hot plate coils. Therefore, it is particularly critical to design the deoxidation and alloying process of Q195 and Q355 steels.
[0005] Furthermore, the continuous casting process is a process in which molten steel solidifies into a solid billet in a certain shape and size. During this process, a large amount of heat is released and carried away by the crystallizer and cooling water. The process is extremely complicated. The main function of the protective slag is to achieve heat transfer and lubrication between the billet shell and the crystallizer, so that the molten steel can solidify quickly to form a casting billet of qualified quality. Summary of the invention
[0006] The object of the present invention is to provide a small slab continuous casting optimization method to solve the problems of easy steel leakage and poor steel billet quality in the existing small slab continuous casting process.
[0007] In order to solve the above problems, the present invention adopts the following technical means: A small slab continuous casting optimization method, which uses composite deoxidation in the molten steel deoxidation stage and determines the properties of the mold slag according to different steel grades; The composite deoxidation comprises using a deoxidizer and a mixture of aluminum blocks and / or silicon-aluminum-calcium to deoxidize molten steel; When the steel grade is Q195 steel, the mold slag is selected based on melting point, viscosity and glass ratio; Among them, the key point of the protective slag for Q195 steel is that the protective slag can provide sufficient liquid slag to ensure the uniformity of the slag film. At the same time, the protective slag for Q195 steel also needs to have good impurity absorption capacity.
[0008] When the steel grade is Q235 steel, the mold slag is selected based on melting point, crystallization temperature and viscosity; Among them, for the protective slag of Q235 steel, the uniformity of heat transfer of the protective slag needs to be given priority, and the protective slag itself needs to have good crack resistance. Therefore, for the protective slag of Q235 steel, it is necessary to limit the heat flux, make the protective slag have a large thermal resistance, achieve weak cooling at the meniscus position, and take lubrication into consideration at the same time.
[0009] When the steel type is Q355 steel, the protective slag is based on the protective slag of Q235 steel, and lithium oxide is added.
[0010] As for the protective slag of Q355 steel, the influence of elements such as titanium, niobium and manganese needs to be considered when determining the protective slag, among which the influence of titanium is mainly considered. Therefore, on the basis of Q235 steel protective slag, lithium oxide is added to reduce the titanium content in the steel grade while adjusting the viscosity, melting point and crystallization temperature of the molten steel.
[0011] Preferably, when the steel type is Q195 steel, the composite deoxidation comprises 400-600 parts of the deoxidizer, 60-120 parts of the silicon-aluminum-calcium, and 40-120 parts of the aluminum block, in parts by weight.
[0012] Further, when the final carbon content of the steel grade is greater than 0.06%, the composite deoxidation comprises 400-450 parts of the deoxidizer, 60-70 parts of the silicon-aluminum-calcium, and 40-50 parts of the aluminum block, by weight; When the final carbon content of the steel grade is 0.04% to 0.05%, the composite deoxidation comprises 450 to 550 parts of the deoxidizer, 80 to 100 parts of the silicon-aluminum-calcium, and 55 to 70 parts of the aluminum block, by weight; When the final carbon content of the steel grade is less than 0.03%, the composite deoxidation comprises 500-600 parts of the deoxidizer, 100-120 parts of the silicon-aluminum-calcium, and 80-120 parts of the aluminum block, by weight.
[0013] Furthermore, when the steel type is Q235 steel, the composite deoxidation comprises 200-500 parts of the deoxidizer, 60-100 parts of the silicon-aluminum-calcium, and 30-80 parts of the aluminum block, calculated by weight.
[0014] Furthermore, when the final carbon content of the steel grade is greater than 0.07%, the composite deoxidation comprises 200-300 parts of the deoxidizer, 60 parts of the silicon-aluminum-calcium, and 30-40 parts of the aluminum block, by weight; When the final carbon content of the steel grade is between 0.04% and 0.06%, the composite deoxidation comprises 250 to 350 parts of the deoxidizer, 60 to 70 parts of the silicon-aluminum-calcium, and 40 to 60 parts of the aluminum block, by weight; When the final carbon content of the steel grade is less than 0.03%, the composite deoxidation comprises 400-500 parts of the deoxidizer, 80-100 parts of the silicon-aluminum-calcium, and 60-80 parts of the aluminum block, calculated by weight.
[0015] Furthermore, when the steel type is Q355 steel, the composite deoxidation comprises 200-450 parts of the deoxidizer and 140-250 parts of the aluminum block, calculated by weight.
[0016] Furthermore, when the final carbon content of the steel grade is greater than 0.07%, the composite deoxidation comprises 200-250 parts of the deoxidizer and 140-155 parts of the aluminum block in parts by weight; When the final carbon content of the steel grade is between 0.04% and 0.06%, the composite deoxidation comprises 250 to 350 parts of the deoxidizer and 160 to 200 parts of the aluminum block in parts by weight; When the final carbon content of the steel grade is less than 0.03%, the composite deoxidation comprises 350-450 parts of the deoxidizer and 200-250 parts of the aluminum block, calculated by weight.
[0017] Furthermore, when the steel grade is Q195 steel, the protective slag includes, by weight, 0.9 to 1 parts of iron oxide, 27 to 28 parts of silicon dioxide, 30 to 31 parts of calcium oxide, 3 to 4 parts of magnesium oxide, 9 to 10 parts of carbon black, 8 to 9 parts of sodium oxide, and 2 to 3 parts of aluminum oxide.
[0018] Furthermore, when the steel grade is Q235 steel, the protective slag includes, by weight, 0.9-1 parts of iron oxide, 24-25 parts of silicon dioxide, 30-31 parts of calcium oxide, 1-2 parts of magnesium oxide, 9-10 parts of carbon black, 8-9 parts of sodium oxide, and 7-8 parts of aluminum oxide.
[0019] Furthermore, when the steel grade is Q355 steel, the protective slag includes, by weight, 0.9~1 parts of iron oxide, 24~25 parts of silicon dioxide, 26~27 parts of calcium oxide, 0.7~1 parts of magnesium oxide, 9~10 parts of carbon black, 15~16 parts of sodium oxide, 5~6 parts of aluminum oxide, and 1~2 parts of lithium oxide.
[0020] During use, the present invention has the following beneficial effects: According to the casting characteristics of different steel grades, determine the reasonable and appropriate continuous casting protection slag to improve the lubrication effect and castability of the protection slag; at the same time, according to the different requirements of steel grades for acid-soluble aluminum and the basicity of the protection slag, use protection slags with different components. When deoxidizing, use a composite deoxidation method to improve the stability of the steel casting process and the stability of the ingot quality.
[0021] Finally, the number of steel leakage accidents was greatly reduced, which not only reduced equipment damage and billet losses caused by steel leakage accidents, but also greatly increased the number of continuous casting furnaces. The produced billets are free of bubbles, slag inclusions and cracks. DETAILED DESCRIPTION
[0022] In order to make the purpose, 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 in combination with 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.
[0023] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. 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] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.
[0025] Example 1 A small slab continuous casting optimization method, which uses composite deoxidation in the molten steel deoxidation stage and determines the properties of the mold slag according to different steel grades; The composite deoxidation comprises using a deoxidizer and a mixture of aluminum blocks and / or silicon-aluminum-calcium to deoxidize molten steel; When the steel grade is Q195 steel, the mold slag is selected based on melting point, viscosity and glass ratio; When the steel grade is Q235 steel, the mold slag is selected based on melting point, crystallization temperature and viscosity; When the steel type is Q355 steel, the protective slag is based on the protective slag of Q235 steel, and lithium oxide is added.
[0026] When the steel type is Q195 steel.
[0027] When the final carbon content of the steel grade is greater than 0.06%, the composite deoxidation comprises 400 parts of the deoxidizer, 60 parts of the silicon-aluminum-calcium, and 40 parts of the aluminum block, by weight; When the final carbon content of the steel grade is between 0.04% and 0.05%, the composite deoxidation comprises 450 parts of the deoxidizer, 80 parts of the silicon-aluminum-calcium, and 55 parts of the aluminum block, by weight; When the final carbon content of the steel grade is less than 0.03%, the composite deoxidation comprises 500 parts of the deoxidizer, 100 parts of the silicon-aluminum-calcium, and 80 parts of the aluminum block, calculated by weight.
[0028] When the steel type is Q235 steel.
[0029] Furthermore, when the final carbon content of the steel grade is greater than 0.07%, the composite deoxidation comprises 200 parts of the deoxidizer, 60 parts of the silicon-aluminum-calcium, and 30 parts of the aluminum block, by weight; When the final carbon content of the steel grade is between 0.04% and 0.06%, the composite deoxidation comprises 250 parts of the deoxidizer, 60 parts of the silicon-aluminum-calcium, and 40 parts of the aluminum block, by weight; When the final carbon content of the steel grade is less than 0.03%, the composite deoxidation comprises 400 parts of the deoxidizer, 80 parts of the silicon-aluminum-calcium, and 60 parts of the aluminum block, calculated by weight.
[0030] When the steel type is Q355 steel.
[0031] Furthermore, when the final carbon content of the steel grade is greater than 0.07%, the composite deoxidation comprises 200 parts of the deoxidizer and 140 parts of the aluminum block, by weight; When the final carbon content of the steel grade is between 0.04% and 0.06%, the composite deoxidation comprises 250 parts of the deoxidizer and 160 parts of the aluminum block by weight; When the final carbon content of the steel grade is less than 0.03%, the composite deoxidation comprises 350 parts of the deoxidizer and 200 parts of the aluminum block, calculated by weight.
[0032] Furthermore, when the steel grade is Q195 steel, the protective slag includes, by weight, 0.9 parts of iron oxide, 27 parts of silicon dioxide, 30 parts of calcium oxide, 3 parts of magnesium oxide, 9 parts of carbon black, 8 parts of sodium oxide, and 2 parts of aluminum oxide.
[0033] Furthermore, when the steel grade is Q235 steel, the protective slag includes, by weight, 0.9 parts of iron oxide, 24 parts of silicon dioxide, 30 parts of calcium oxide, 1 part of magnesium oxide, 9 parts of carbon black, 8 parts of sodium oxide, and 7 parts of aluminum oxide.
[0034] Furthermore, when the steel grade is Q355 steel, the protective slag includes, by weight, 0.9 parts of iron oxide, 24 parts of silicon dioxide, 26 parts of calcium oxide, 0.7 parts of magnesium oxide, 9 parts of carbon black, 15 parts of sodium oxide, 5 parts of aluminum oxide, and 1 part of lithium oxide.
[0035] Example 2 A small slab continuous casting optimization method, which uses composite deoxidation in the molten steel deoxidation stage and determines the properties of the mold slag according to different steel grades; The composite deoxidation comprises using a deoxidizer and a mixture of aluminum blocks and / or silicon-aluminum-calcium to deoxidize molten steel; When the steel grade is Q195 steel, the mold slag is selected based on melting point, viscosity and glass ratio; When the steel grade is Q235 steel, the mold slag is selected based on melting point, crystallization temperature and viscosity; When the steel type is Q355 steel, the protective slag is based on the protective slag of Q235 steel, and lithium oxide is added.
[0036] When the steel type is Q195 steel.
[0037] When the final carbon content of the steel grade is greater than 0.06%, the composite deoxidation comprises 450 parts of the deoxidizer, 70 parts of the silicon-aluminum-calcium, and 50 parts of the aluminum block, by weight; When the final carbon content of the steel grade is between 0.04% and 0.05%, the composite deoxidation comprises 550 parts of the deoxidizer, 100 parts of the silicon-aluminum-calcium, and 70 parts of the aluminum block, by weight; When the final carbon content of the steel grade is less than 0.03%, the composite deoxidation comprises 600 parts of the deoxidizer, 120 parts of the silicon-aluminum-calcium, and 120 parts of the aluminum block, by weight.
[0038] When the steel type is Q235 steel.
[0039] Furthermore, when the final carbon content of the steel grade is greater than 0.07%, the composite deoxidation comprises 300 parts of the deoxidizer, 60 parts of the silicon-aluminum-calcium, and 40 parts of the aluminum block, by weight; When the final carbon content of the steel grade is between 0.04% and 0.06%, the composite deoxidation comprises 350 parts of the deoxidizer, 70 parts of the silicon-aluminum-calcium, and 60 parts of the aluminum block, by weight; When the final carbon content of the steel grade is less than 0.03%, the composite deoxidation comprises 500 parts of the deoxidizer, 100 parts of the silicon-aluminum-calcium, and 80 parts of the aluminum block, calculated by weight.
[0040] When the steel type is Q355 steel.
[0041] Furthermore, when the final carbon content of the steel grade is greater than 0.07%, the composite deoxidation comprises 2505 parts of the deoxidizer and 155 parts of the aluminum block, by weight; When the final carbon content of the steel grade is between 0.04% and 0.06%, the composite deoxidation comprises 350 parts of the deoxidizer and 200 parts of the aluminum block, by weight; When the final carbon content of the steel grade is less than 0.03%, the composite deoxidation comprises 450 parts of the deoxidizer and 250 parts of the aluminum block, calculated by weight.
[0042] Furthermore, when the steel grade is Q195 steel, the protective slag includes, by weight, 1 part of iron oxide, 28 parts of silicon dioxide, 31 parts of calcium oxide, 4 parts of magnesium oxide, 10 parts of carbon black, 9 parts of sodium oxide, and 3 parts of aluminum oxide.
[0043] Furthermore, when the steel grade is Q235 steel, the protective slag includes, by weight, 1 part of iron oxide, 25 parts of silicon dioxide, 31 parts of calcium oxide, 2 parts of magnesium oxide, 10 parts of carbon black, 9 parts of sodium oxide, and 8 parts of aluminum oxide.
[0044] Furthermore, when the steel grade is Q355 steel, the protective slag includes, by weight, 1 part of iron oxide, 25 parts of silicon dioxide, 27 parts of calcium oxide, 1 part of magnesium oxide, 10 parts of carbon black, 16 parts of sodium oxide, 6 parts of aluminum oxide, and 5 parts of lithium oxide.
[0045] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for optimizing continuous casting of small slabs, characterized in that: Composite deoxidation is used in the molten steel deoxidation stage, and the properties of the protective slag are determined according to different steel grades; The composite deoxidation comprises using a deoxidizer and a mixture of aluminum blocks and / or silicon-aluminum-calcium to deoxidize molten steel; When the steel grade is Q195 steel, the mold slag is selected based on melting point, viscosity and glass ratio; When the steel grade is Q235 steel, the mold slag is selected based on melting point, crystallization temperature and viscosity; When the steel type is Q355 steel, the protective slag is based on the protective slag of Q235 steel, and lithium oxide is added.
2. The small slab continuous casting optimization method according to claim 1, characterized in that: When the steel type is Q195 steel, the composite deoxidation comprises 400-600 parts of the deoxidizer, 60-120 parts of the silicon-aluminum-calcium, and 40-120 parts of the aluminum block, calculated by weight.
3. A small slab continuous casting optimization method according to claim 2, characterized in that: When the final carbon content of the steel grade is greater than 0.06%, the composite deoxidation comprises 400-450 parts of the deoxidizer, 60-70 parts of the silicon-aluminum-calcium, and 40-50 parts of the aluminum block, by weight; When the final carbon content of the steel grade is 0.04% to 0.05%, the composite deoxidation comprises 450 to 550 parts of the deoxidizer, 80 to 100 parts of the silicon-aluminum-calcium, and 55 to 70 parts of the aluminum block, by weight; When the final carbon content of the steel grade is less than 0.03%, the composite deoxidation comprises 500-600 parts of the deoxidizer, 100-120 parts of the silicon-aluminum-calcium, and 80-120 parts of the aluminum block, by weight.
4. The small slab continuous casting optimization method according to claim 1, characterized in that: When the steel type is Q235 steel, the composite deoxidation comprises 200-500 parts of the deoxidizer, 60-100 parts of the silicon-aluminum-calcium, and 30-80 parts of the aluminum block, calculated by weight.
5. The small slab continuous casting optimization method according to claim 4, characterized in that: When the final carbon content of the steel grade is greater than 0.07%, the composite deoxidation comprises 200-300 parts of the deoxidizer, 60 parts of the silicon-aluminum-calcium, and 30-40 parts of the aluminum block, by weight; When the final carbon content of the steel grade is between 0.04% and 0.06%, the composite deoxidation comprises 250 to 350 parts of the deoxidizer, 60 to 70 parts of the silicon-aluminum-calcium, and 40 to 60 parts of the aluminum block, by weight; When the final carbon content of the steel grade is less than 0.03%, the composite deoxidation comprises 400-500 parts of the deoxidizer, 80-100 parts of the silicon-aluminum-calcium, and 60-80 parts of the aluminum block, calculated by weight.
6. The small slab continuous casting optimization method according to claim 1, characterized in that: When the steel type is Q355 steel, the composite deoxidation comprises 200-450 parts of the deoxidizer and 140-250 parts of the aluminum block, calculated by weight.
7. A small slab continuous casting optimization method according to claim 6, characterized in that: When the final carbon content of the steel grade is greater than 0.07%, the composite deoxidation comprises 200-250 parts of the deoxidizer and 140-155 parts of the aluminum block by weight; When the final carbon content of the steel grade is between 0.04% and 0.06%, the composite deoxidation comprises 250 to 350 parts of the deoxidizer and 160 to 200 parts of the aluminum block in parts by weight; When the final carbon content of the steel grade is less than 0.03%, the composite deoxidation comprises 350-450 parts of the deoxidizer and 200-250 parts of the aluminum block, calculated by weight.
8. The small slab continuous casting optimization method according to claim 1, characterized in that: When the steel grade is Q195 steel, the protective slag comprises, by weight, 0.9-1 parts of iron oxide, 27-28 parts of silicon dioxide, 30-31 parts of calcium oxide, 3-4 parts of magnesium oxide, 9-10 parts of carbon black, 8-9 parts of sodium oxide, and 2-3 parts of aluminum oxide.
9. The small slab continuous casting optimization method according to claim 1, characterized in that: When the steel grade is Q235 steel, the protective slag comprises, by weight, 0.9-1 parts of iron oxide, 24-25 parts of silicon dioxide, 30-31 parts of calcium oxide, 1-2 parts of magnesium oxide, 9-10 parts of carbon black, 8-9 parts of sodium oxide, and 7-8 parts of aluminum oxide.
10. The small slab continuous casting optimization method according to claim 1, characterized in that: When the steel grade is Q355 steel, the protective slag comprises, by weight, 0.9-1 parts of iron oxide, 24-25 parts of silicon dioxide, 26-27 parts of calcium oxide, 0.7-1 parts of magnesium oxide, 9-10 parts of carbon black, 15-16 parts of sodium oxide, 5-6 parts of aluminum oxide, and 1-2 parts of lithium oxide.