A cutting method for a mixed casting blank of different steel grades
By adopting a constant pulling speed and time determination method during the cutting process of mixed steel billets, the cutting rules were optimized, solving the problem of poor cutting effect in the existing technology, and realizing accurate cutting of mixed billets and improving the yield.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-24
- Publication Date
- 2026-04-14
AI Technical Summary
Existing technologies result in poor cutting performance during the cutting of mixed steel billets, leading to an increase in the number of mixed billets and a decrease in the yield.
Continuous casting is carried out using a constant casting speed method. The starting and ending positions of the mixed casting billet are determined by calculating the time. The continuous casting sequence and cutting mode of the steel grade are adjusted, and the cutting rules are optimized to accurately cut the mixed casting billet.
It enables accurate cutting of mixed steel billets, reduces the number of mixed billet pieces and the overall length, and improves the yield of continuously cast slabs.
Smart Images
Figure CN119819894B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of continuous casting technology for hot-rolled thick plates of different steel grades, and in particular to a method for cutting mixed billets of different steel grades. Background Technology
[0002] With the development of modern continuous casting technology, in order to improve production efficiency and yield, continuous casting technology using different steel grades is commonly adopted, i.e., dissimilar steel grade continuous casting technology. This process generates a large number of mixed-grade billets. Since thick and wide plate continuous casting billets have many varieties and significant variations in alloy composition, and the frequency of dissimilar steel grade continuous casting is high, mixed-grade billets are easily generated during the process. The presence of mixed-grade billets has a significant impact on the yield of continuously cast slabs. Simultaneously, during continuous casting, to meet order requirements and the needs of the next process, the cast billets need to be cut into slabs of a certain length, i.e., continuous casting slab cutting. Because continuous casting production is continuous, the cutting plan for mixed-grade billets needs to be rescheduled so that these continuously cast slabs that do not meet the composition requirements are removed after production, while maximizing order fulfillment and minimizing the generation of mixed-grade billets.
[0003] Currently, most steel mills use methods such as continuous casting information, billet temperature information, billet weight, and preset target billet weight and length to determine the billet weight deviation. However, this leads to weight loss and reduces yield. Furthermore, this method increases the number of mixed billets of dissimilar steel grades, increasing their overall length and further reducing yield. Therefore, a more accurate method for cutting continuously cast slabs in the process of mixing dissimilar steel grades is urgently needed. Summary of the Invention
[0004] This application provides a method for cutting mixed-grade steel billets to solve the problem of poor cutting effect in existing mixed-grade steel billet production.
[0005] Technical issues.
[0006] In a first aspect, this application provides a method for cutting a mixed-cast billet of dissimilar steel grades, the method comprising:
[0007] A constant casting speed method is used to continuously cast different steel grades, and the starting position and ending position of the mixed casting blank are determined by calculating the time; wherein, the different steel grades include a first steel grade and a second steel grade;
[0008] The continuous casting sequence of the first and second steel grades is adjusted according to the planned cutting length of the continuous casting billets of the first and second steel grades.
[0009] The cutting pattern of the mixed-cast billet is adjusted according to the planned cutting length of the continuous casting billets of the first and second steel grades.
[0010] Optionally, the time corresponding to the starting position of the mixed-cast billet satisfies the following relationship:
[0011] F(t) = H / V*60 + T1
[0012] H represents the metallurgical length of the slab continuous casting machine, in meters; V represents the casting speed, in meters per minute; and T1 represents the mixing time of the molten steel of different grades in the tundish corresponding to the starting position of the mixed slab, in seconds.
[0013] Optionally, the time corresponding to the endpoint position of the cast-in-place billet satisfies the following relationship:
[0014] F(t) = H / V*60 + T2
[0015] H represents the metallurgical length of the slab continuous casting machine, in meters; V represents the casting speed, in meters per minute; and T2 represents the mixing time of the dissimilar steel molten steel in the tundish corresponding to the end position of the mixed slab, in seconds.
[0016] Optionally, the pulling speed is 0.65-0.95 m / min.
[0017] Optionally, the first steel grade can be adjusted according to the planned cutting length of the continuously cast billet for the first and second steel grades.
[0018] The continuous casting sequence of the first steel grade and the second steel grade includes: when the planned cutting length of the continuous casting billet of the first steel grade is greater than the planned cutting length of the continuous casting billet of the second steel grade,
[0019] The second steel grade will be placed in the first furnace during continuous casting.
[0020] The first steel grade is scheduled for the next heat.
[0021] Optionally, the step of adjusting the planned cutting length of the continuously cast billet based on the first and second steel grades is described.
[0022] Cutting patterns for cast-in-place billets include:
[0023] When the planned cutting length of the continuous casting billet of the first steel grade is greater than the planned cutting length of the continuous casting billet of the second steel grade
[0024] The starting point of the mixed casting billet is set at the head position of the continuous casting billet;
[0025] The endpoint of the mixed casting billet is set at the tail end of the continuous casting billet for cutting.
[0026] Optionally, the starting and ending positions of the cut of the mixed-cast billet satisfy the following relationship:
[0027] min 混 =S混1 +S 混2 +....+S 混n
[0028] min 混 =S 坯头 —S 混开始
[0029] min 混 =S 坯尾 —S 混结束
[0030] In the formula, S 混 S represents the total length of the cast-in-place billet, in meters (m); 混1 S is the length of the first cast-in-place billet, in meters (m); 混2 S is the length of the second cast-in-place billet, in meters (m); 混n S represents the length of the last cast-in-place billet, in meters (m). 坯头 The position of the billet head where the mixed-cast billet begins to be located in the continuous casting billet is m; S 坯尾 The starting point of the mixed casting is located at the tail position of the continuously cast billet, m; S 混开始 The starting position of the cast-in-place billet is m; S 混结束 The endpoint of the cast-in-place billet is in meters (m).
[0031] Optionally, during the continuous casting process, the weight of molten steel in the tundish is 20-100t.
[0032] The technical solutions provided in this application have the following advantages compared with the prior art:
[0033] The method for cutting mixed-cast billets of different steel grades provided in this application adopts time as a criterion to optimize the cutting rules and casting sequence in the continuous casting process of different steel grades. This method enables accurate cutting of mixed-cast billets generated during the production of thick plate mixed-cast slabs of different steel grades, reduces the number of mixed-cast billet pieces and the overall length of the mixed-cast billets, and achieves the shortest overall length of the mixed-cast billets, thereby maximizing the yield of continuous casting slabs. Attached Figure Description
[0034] 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.
[0035] 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.
[0036] Picture 1 A flowchart illustrating a method for cutting a mixed-type steel billet according to an embodiment of this application;
[0037] Picture 2 This is a schematic diagram showing the starting point position for cutting a mixed-cast billet, provided in an embodiment of this application. Detailed Implementation
[0038] 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.
[0039] 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.
[0040] 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, 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.
[0041] 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.
[0042] Firstly, this application provides a method for cutting mixed-grade steel billets; please refer to [link to relevant documentation]. Picture 1 The method includes:
[0043] S1. A constant casting speed is used to continuously cast different steel types, and the starting position and ending position of the mixed casting blank are determined by calculating the time; wherein, the different steel types include a first steel type and a second steel type;
[0044] In some implementations, the time corresponding to the starting position of the cast-in-place billet satisfies the following relationship:
[0045] F(t) = H / V*60 + T1
[0046] H represents the metallurgical length of the slab continuous casting machine, in meters; V represents the casting speed, in meters per minute; and T1 represents the mixing time of the molten steel of different grades in the tundish corresponding to the starting position of the mixed slab, in seconds.
[0047] H / V*60 represents the time it takes for molten steel to travel from the crystallizer to the cut point of the continuously cast billet. The positive effect of the time corresponding to the starting position of the mixed-cast billet satisfying the above relationship is that the starting position of the mixed-cast billet can be accurately determined.
[0048] In some implementations, the time corresponding to the endpoint of the cast-in-place billet satisfies the following relationship:
[0049] F(t) = H / V*60 + T2
[0050] H represents the metallurgical length of the slab continuous casting machine, in meters; V represents the casting speed, in meters per minute; and T2 represents the mixing time of the dissimilar steel molten steel in the tundish corresponding to the end position of the mixed slab, in seconds.
[0051] The positive effect of the time corresponding to the end position of the mixed-cast billet satisfying the above relationship is that the starting position of the mixed-cast billet can be accurately determined.
[0052] In some embodiments, the pulling speed is 0.65-0.95 m / min.
[0053] The positive effects of using a constant casting speed for continuous casting of different steel grades are: avoiding the impact of variable casting speed and liquid level changes on the casting process.
[0054] The positive effect of controlling the casting speed to 0.65-0.95 m / min is that it can accurately cover the casting speed range for medium and heavy plate continuous casting billets. Specifically, this casting speed can be 0.65 m / min, 0.85 m / min, 0.95 m / min, etc.
[0055] S2. Adjust the continuous casting sequence of the first steel grade and the second steel grade according to the planned cutting length of the continuous casting billet.
[0056] In some embodiments, the planned cutting length of the continuously cast billet is adjusted according to the first steel grade and the second steel grade.
[0057] The sequence of continuous casting for the first and second steel grades includes: when the planned cutting length of the continuous casting billet for the first steel grade is greater than the planned cutting length of the continuous casting billet for the second steel grade...
[0058] The second steel grade will be placed in the first furnace during continuous casting.
[0059] The first steel grade is scheduled for the next heat.
[0060] The positive effect of setting the above continuous casting sequence is that it minimizes the length of the cut mixed billet.
[0061] S3. Adjust the cutting mode of the mixed-cast billet according to the planned cutting length of the continuous casting billet of the first steel grade and the second steel grade.
[0062] In some embodiments, the step of cutting the continuously cast billet according to the planned cutting length of the first steel grade and the second steel grade is...
[0063] Adjusting the cutting pattern of the mixed-cast billet includes:
[0064] When the planned cutting length of the continuous casting billet of the first steel grade is greater than the planned cutting length of the continuous casting billet of the second steel grade
[0065] The starting point of the mixed casting billet is set at the head position of the continuous casting billet;
[0066] The endpoint of the mixed casting billet is set at the tail end of the continuous casting billet for cutting.
[0067] The positive effect of setting the above cutting mode is that it minimizes the length of the cut concrete billet.
[0068] In some embodiments, the starting and ending positions of the cut of the mixed-cast billet satisfy the following relationship:
[0069] min 混 =S 混1 +S 混2 +....+S 混n
[0070] min 混 =S 坯头 —S 混开始
[0071] min 混 =S 坯尾 —S 混结束
[0072] In the formula, S 混 S represents the total length of the cast-in-place billet, in meters (m); 混1 S is the length of the first cast-in-place billet, in meters (m); 混2 S is the length of the second cast-in-place billet, in meters (m); 混n S represents the length of the last cast-in-place billet, in meters (m). 坯头 The position of the billet head where the mixed-cast billet begins to be located in the continuous casting billet is m; S 坯尾 The starting point of the mixed casting is located at the tail position of the continuously cast billet, m; S 混开始 The starting position of the cast-in-place billet is m; S 混结束 The endpoint of the cast-in-place billet is in meters (m).
[0073] The exact positions of the start and end points of the solidified mixed-cast billet are used as the basis for determining the length of the continuous casting billet containing the start and end points. Specifically, the start point of the solidified mixed-cast billet should be closer to the head of the continuous casting billet, and the end point should be closer to the tail of the continuous casting billet, ensuring the shortest possible mixed-cast billet length. (See [reference needed]). Picture 2 The diagram shows the starting point position for cutting the mixed-cast billet. The starting point position for cutting the mixed-cast billet must satisfy the above relationship.
[0074] In some embodiments, during the continuous casting process, the weight of molten steel in the tundish is 20-100t.
[0075] The positive effects of controlling the weight of molten steel in the tundish to 20-100t include: it covers the vast majority of tundish volumes, and the determination is most accurate within this volume range. Specifically, the weight of molten steel in the tundish can be 20t, 60t, 100t, etc.
[0076] 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.
[0077] Example 1
[0078] A continuous casting industrial experiment of dissimilar steel grades was conducted on a slab continuous casting machine at a steel plant. The initial weight of molten steel in the tundish was 20 tons. The production process was converter + RH refining + continuous casting. The steel grades to be cast were Q345 and D36. The slab thickness was 300 mm, the width was 2000 mm, the casting speed was 0.95 m / min, and the metallurgical length was 31 m. The mixing time of the dissimilar steel grades in the tundish at the starting and ending positions of the mixed casting was calculated using numerical simulation: T1 was 450 s and T2 was 840 s. The planned lengths of the Q345 slabs after cutting were 2.8 m (three pieces), 3.2 m (seven pieces), and a total of 10 pieces. The planned lengths of the D36 slabs after cutting were all 4.5 m (seven pieces). The method for cutting the mixed casting slabs was determined as follows:
[0079] (1) In the continuous casting process of dissimilar steel grades, time t is used to accurately determine the starting point and ending point after the solidification of the mixed casting billet of dissimilar steel grades in medium and thick plates. Wherein t needs to meet the following requirements: F(t)=H / V*60+T1
[0080] According to the above formula, the starting time after the solidification of the mixed-cast billet during the continuous casting of different steel grades is...
[0081] F(t start) = 31 / 0.95*60+450 = 2407.9s, which means that 2407.9s after the start of the second heat of molten steel entering the tundish is the starting point after the solidification of the mixed billet;
[0082] The time to the end of solidification of the mixed billet during continuous casting of different steel grades is F(t) = H / V*60 + T2
[0083] F(t start) = 31 / 0.95*60 + 840 = 2797.9s, which means that 2797.9s after the start of the second heat of molten steel entering the tundish is the end point after the solidification of the mixed billet;
[0084] (2) Optimization of casting sequence: Since the length of the continuous casting billet after the planned cutting is different in the two heats before and after the mixed casting of different steel grades, the heat Q345 with the shorter length of the continuous casting billet after the planned cutting is placed in the first heat during continuous casting, while the next heat of different steel grades is the heat D36 with the longer length of the continuous casting billet after the planned cutting.
[0085] (3) Cutting mode optimization: The accurate positions of the starting and ending points of the mixed-cast billet after solidification are used as the basis for the length of the continuous casting billet where the starting and ending points of the mixed-cast billet are located. That is, the starting point of the mixed-cast billet after solidification should be closer to the head position of the continuous casting billet where the starting point of the mixed-cast billet after solidification is located, and the ending point of the mixed-cast billet after solidification should be closer to the tail position of the continuous casting billet where the ending point of the mixed-cast billet is located, to ensure the shortest length of the mixed-cast billet. The starting point position of the mixed-cast billet cutting should meet the following conditions:
[0086] min 混 =S 混1 +S 混2 +....+S 混n
[0087] min 混 =S 坯头 —S 混开始
[0088] min 混 =S 坯尾 —S 混结束
[0089] The numerical simulation results show that at the beginning of the concrete pouring, the length of the first concrete pouring blank is Smix1 = 2.8m; Smix2 = 2.8m; Smixn ends at the end position of the concrete pouring blank, that is, the length of the last concrete pouring blank is Smixn = 4.5m; therefore, it can be seen that the total length of the concrete pouring blank is Smix = 10.1m.
[0090] Example 2
[0091] A continuous casting industrial experiment of dissimilar steel grades was conducted on a single-strand slab continuous casting machine at a steel plant. The initial weight of molten steel in the tundish was 100 tons. The production process was converter + RH refining + continuous casting. The steel grades to be cast were X65 and E36. The slab thickness was 400 mm, the width was 2000 mm, the casting speed was 0.65 m / min, and the metallurgical length was 33.2 m. The mixing time of the dissimilar steel grades in the tundish at the starting and ending positions of the mixed casting was calculated using numerical simulation: T1 was 670 s and T2 was 1730 s. The planned lengths of the X65 slabs after cutting were all 3.2 m, totaling 10 slabs. The planned lengths of the E36 slabs after cutting were 2 slabs of 3.8 m and 6 slabs of 4.5 m, totaling 8 slabs. The method for cutting the mixed casting slabs was determined as follows:
[0092] (1) In the continuous casting process of dissimilar steel grades, time t is used to accurately determine the starting point and ending point after the solidification of the mixed casting billet of dissimilar steel grades in medium and thick plates. Wherein t needs to meet the following requirements: F(t)=H / V*60+T1
[0093] The time from the start of solidification of the mixed billet during continuous casting of different steel grades is
[0094] F(t start) = 33.2 / 0.65 * 60 + 670 = 3734.6s, which means that 3734.6s after the start of the second heat of molten steel entering the tundish is the starting point after the solidification of the mixed billet;
[0095] The time to the end of solidification of the mixed billet during continuous casting of different steel grades is F(t) = H / V*60 + T2
[0096] F(t start) = 33.2 / 0.65 * 60 + 1730 = 4794.6s, which means that 4794.6s after the start of the second heat of molten steel entering the tundish is the end point after the solidification of the mixed billet;
[0097] (2) Optimization of casting sequence: Since the length of the continuous casting billet after the planned cutting is different in the two heats before and after the mixed casting of different steel grades, the heat X65 with the shorter length of the continuous casting billet after the planned cutting is placed in the first heat during continuous casting, while the next heat of different steel grades is the heat E36 with the longer length of the continuous casting billet after the planned cutting.
[0098] (3) Cutting mode optimization: The accurate positions of the starting and ending points of the mixed-cast billet after solidification are used as the basis for the length of the continuous casting billet where the starting and ending points of the mixed-cast billet are located. That is, the starting point of the mixed-cast billet after solidification should be closer to the head position of the continuous casting billet where the starting point of the mixed-cast billet after solidification is located, and the ending point of the mixed-cast billet after solidification should be closer to the tail position of the continuous casting billet where the ending point of the mixed-cast billet is located, to ensure the shortest length of the mixed-cast billet. The starting point position of the mixed-cast billet cutting should meet the following conditions:
[0099] min 混 =S 混1 +S混2 +....+S 混n
[0100] min 混 =S 坯头 —S 混开始
[0101] min 混 =S 坯尾 —S 混结束
[0102] Numerical simulation results show that at the beginning of the concrete pouring process, the length of the first concrete pouring blank is Smix1 = 3.2m; Smix2 = 3.2m; Smix3 = 3.2m; and Smixn ends at the end position of the concrete pouring blank, that is, the length of the last concrete pouring blank is Smixn = 3.8m. Therefore, it can be seen that the total length of the concrete pouring blank is Smix = 13.4m.
[0103] Example 3
[0104] An industrial experiment was conducted on a single-strand slab continuous casting machine at a steel plant to continuously cast different steel grades. The initial weight of the molten steel in the tundish was 70 tons.
[0105] The production process is converter + RH refining + continuous casting. The steel grades for continuous casting are X65 and E36. The slab thickness is 400mm, the width is 2000mm, the casting speed is 0.65m / min, and the metallurgical length is 33.2m. After the mixed casting begins, the first two slabs are determined to be mixed casting slabs of 3.2m each with a length of 6.4m, and the last two slabs are mixed casting slabs of 9m each with a length of 9m. The total length of the mixed casting slabs is 15.4m.
[0106] The method described in this application achieves the shortest possible length for the cast billet. Furthermore, by using time as the criterion, deviations caused by factors such as weight and length are reduced, thereby increasing the yield.
[0107] 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 cutting mixed-grade steel billets, characterized in that, The method includes: A constant casting speed method is used to continuously cast different steel grades, and the starting position and ending position of the mixed casting blank are determined by calculating the time; wherein, the different steel grades include a first steel grade and a second steel grade; The continuous casting sequence of the first and second steel grades is adjusted according to the planned cutting length of the continuous casting billets of the first and second steel grades. The cutting pattern of the mixed-cast billet is adjusted according to the planned cutting length of the continuous casting billet of the first steel grade and the second steel grade. The time corresponding to the starting position of the mixed casting blank satisfies the following relationship: F(t) = H / V*60 + T1 H represents the metallurgical length of the slab continuous casting machine, in meters; V represents the casting speed, in meters per minute; T1 represents the mixing time of the molten steel of different grades in the tundish corresponding to the starting position of the mixed slab, in seconds. The time corresponding to the endpoint position of the cast-in-place billet satisfies the following relationship: F(t) = H / V*60 + T2 H represents the metallurgical length of the slab continuous casting machine, in meters; V represents the casting speed, in meters per minute; T2 represents the mixing time of the dissimilar steel molten steel in the tundish corresponding to the end position of the mixed slab, in seconds. The continuous casting sequence of the first steel grade and the second steel grade is adjusted according to the planned cutting length of the continuous casting billet, including: when the planned cutting length of the continuous casting billet of the first steel grade is greater than the planned cutting length of the continuous casting billet of the second steel grade, the second steel grade is placed in the first heat during continuous casting; the heat of the first steel grade is placed in the next heat. The step of adjusting the cutting mode of the mixed-cast billet according to the planned cutting length of the continuously cast billets of the first and second steel grades includes: When the planned cutting length of the first steel grade continuous casting billet is greater than the planned cutting length of the second steel grade continuous casting billet, the starting position of the mixed casting billet is set at the head position of the continuous casting billet; the ending position of the mixed casting billet is set at the tail position of the continuous casting billet for cutting.
2. The method according to claim 1, characterized in that, The pulling speed is 0.65-0.95 m / min.
3. The method according to claim 1, characterized in that, During the continuous casting process, the weight of molten steel in the tundish is 20-100t.
Citation Information
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Method for determining head and tail positions and length of mixed cast blank based on continuous molten steel temperature measurement
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