Fixed-length cutting system parameter adjusting method and continuous casting extra-large round billet production method

Abstract

The invention relates to the technical field of continuous casting, in particular to a fixed-length cutting system parameter adjusting method and a continuous casting extra-large round billet production method.The fixed-length cutting system parameter adjusting method comprises the steps that a fixed-length cutting system is used for cutting a first casting blank, the length Y1 of the first casting blank in the high-temperature state is measured, whether X-0.005 < = Y1 < = X + 0.005 or not is judged, and if not, the first casting blank is cut; if Y1 is equal to Y2, adjusting parameters of the fixed-length cutting system according to the correction value b1, X being a control fixed length, S being a tolerance upper limit, and the correction value b1 being a difference value between Y1 and X; and the steps are repeated till the length Yn of the nth casting blank meets the condition that Yn is larger than or equal to X-0.005 and smaller than or equal to X + 0.005, and parameter adjustment of the fixed-length cutting system is completed. The sizing qualification rate of the extra-large round billet continuous casting machine is increased, so that the appearance quality of products is improved, the saw changing frequency is reduced, and the production benefit is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of continuous casting, and in particular to a method for adjusting parameters of a fixed-length cutting system and a method for producing a continuous casting extra-large round billet. Background Art

[0002] The continuous casting line currently produces ultra-large cross-section round billets ranging from 600-1200mm. The main products include steel for wind turbine rings, high-pressure boiler tubes, oil and gas pipe billets, forging steel, tooling, and other high-end manufacturing applications. These products are primarily intended for export, where customers have extremely stringent requirements for appearance and, in particular, cut-to-length. Therefore, the stability and accuracy of the cut-to-length system in the continuous casting and cutting process directly impacts the company's efficient and stable production operations and product quality. Faced with the current challenging market conditions in the steel industry, improving the cut-to-length ratio can significantly meet customer needs, demonstrating the company's management and technical expertise through detailed analysis and ultimately enhancing the product's market credibility. For export-oriented billets, inaccurate cut-to-length directly affects the appearance of the billets, failing to meet customer needs and reducing the competitiveness of specialty steel products. Furthermore, excessive cut-to-length deviations can lead to losses per ton of steel and a short-length rate, directly impacting economic efficiency.

[0003] Currently, commonly used cut-to-length systems include laser, infrared, and encoder systems. Laser cut-to-length systems offer greater accuracy and stability. However, laser cut-to-length data is affected by multiple factors, including the torch cutting machine's gantry position, roller table, the thermal expansion coefficient of the ingot, and cross-sectional specifications. This makes it difficult to achieve a high cut-to-length qualification rate. Summary of the Invention

[0004] The purpose of the present invention is to address the defects of the existing technology and provide a method for adjusting the parameters of the fixed-length cutting system and a method for producing continuous casting extra-large round billets, thereby improving the fixed-length qualification rate of the extra-large round billet continuous casting machine, thereby improving the product appearance quality, reducing the frequency of sawing changes, and increasing production efficiency.

[0005] In order to solve the above technical problems, in a first aspect, the present invention provides a method for adjusting parameters of a cut-to-length cutting system, comprising:

[0006] Use the cut-to-length system to cut the first ingot. Measure the length Y1 of the first ingot at high temperature and determine whether X-0.005≤Y1≤X+0.005 holds. If not, adjust the parameters of the cut-to-length system based on the correction value b1, where X is the control length, S is the upper tolerance limit, and the correction value b1 is the difference between Y1 and X.

[0007] Repeat the above steps until the length of the billet n is Y n Satisfy X-0.005≤Y n ≤X+0.005, the parameter adjustment of the fixed-length cutting system is completed.

[0008] Further, the method for adjusting the parameters of the fixed-length cutting system according to the correction value b1 includes: calculating the correction value b1 = |Y1 - X|. If Y1 > X, adjust the parameters of the fixed-length cutting system to reduce the theoretical cutting length by b1. If Y1 < X, adjust the parameters of the fixed-length cutting system to increase the theoretical cutting length by b1.

[0009] In some embodiments, the control fixed length X is determined according to the required fixed length L, the thermal expansion coefficient a, and the upper tolerance limit S: X = L×a + (S - 0.01).

[0010] Further, the thermal expansion coefficient a is determined according to the diameter of the round billet and the drawing speed.

[0011] In some embodiments, the thermal expansion coefficient a is corrected using a correction coefficient K, where K is a coefficient related to the ambient temperature.

[0012] In a second aspect, the present invention provides a method for producing continuously cast extra-large round billets, including:

[0013] Determine the required fixed length L and the allowable tolerance range 0 to S. Calculate the thermal expansion coefficient a according to the specifications of the billet, the drawing speed, and the required fixed length L. Calculate the control fixed length X according to the required fixed length L, the thermal expansion coefficient a, and the upper tolerance limit S;

[0014] Cut the billet online, measure the length Y1 of the first billet, and determine whether X - 0.005 ≤ Y1 ≤ X + 0.005 holds. If not, calculate the correction value b1 and adjust the parameters of the fixed-length cutting system according to the correction value b1;

[0015] Repeat the above steps until the length Y of the nth billet n satisfies X - 0.005 ≤ Y n ≤ X + 0.005, then complete the parameter adjustment of the fixed-length cutting system;

[0016] Use the fixed-length cutting system with adjusted parameters to cut the billet online;

[0017] Load the billet into a slow-cooling pit for slow cooling until it reaches room temperature.

[0018] Further, start adjusting the parameters of the fixed-length cutting system from the second billet.

[0019] Further, before each online cutting of the billet using the fixed-length cutting system with adjusted parameters, it is necessary to check that the original position returned by the large vehicle of the flame cutting machine is always the same. <Furthermore, after the ingot is cooled to room temperature, its length L0 is measured, and the number of ingots with a length within the range of L≤L0≤L+S is counted as N0, the total number of ingots measured is N, and the qualified rate of fixed length is calculated as N0 / N.

[0021] Furthermore, when measuring the ingot, the point at the worst position of the cutting surface is selected as the reference point for measurement.

[0022] The beneficial effects of the present invention are:

[0023] 1. The present invention adjusts the parameters of the fixed-length cutting system according to the difference between the billet length obtained by each cutting and the controlled fixed length X, so that the billet length cut by the fixed-length cutting system gradually approaches the controlled fixed length, thereby improving the fixed-length qualification rate.

[0024] 2. This invention rationally determines the thermal expansion coefficient of continuous casting extra-large round billets under different casting speeds, billet specifications, and other working conditions, and summarizes the influence of the correction coefficient on the cut-to-length accuracy under different ambient temperatures. This allows for accurate calculation of the controlled cut-to-length X of the billet at production temperature, ensuring that the billet meets customer requirements after cooling to room temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the cutting and length measurement of an extra-large round billet according to the present invention;

[0026] Figure 2 Schematic diagram of the qualified rate of extra-large round billets in the embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0028] like Figure 1 As shown, the present invention provides a method for adjusting parameters of a fixed-length cutting system, comprising:

[0029] Use the fixed length cutting system to cut the No. 1 ingot, measure the length Y1 of the No. 1 ingot at high temperature, and judge whether X-0.005≤Y1≤X+0.005 is established. If not, adjust the parameters of the fixed length cutting system according to the correction value b1, where X is the control fixed length and the correction value b1 is the difference between Y1 and X. After each ingot is cut, its length measurement at high temperature is carried out by an offline laser length measurement stand, and the offline stand needs to use a calibration billet (length L 标 ) to calibrate to ensure its measurement accuracy;

[0030] Repeat the above steps until the length of the billet n is Y nSatisfy X - 0.005 ≤ Y n ≤ X + 0.005, then the parameter adjustment of the fixed - length cutting system is completed.

[0031] It should be noted that due to the influence of factors such as the original position of the large vehicle of the flame cutting machine, the roller table, the thermal expansion coefficient of the continuous casting billet, and the section specifications, even if the laser fixed - length setting of the fixed - length cutting system is accurate, the qualified rate of the length of the cut continuous casting billet is still not high, affecting production efficiency and production benefits.

[0032] The present invention adjusts the parameters of the fixed - length cutting system according to the difference between the length of the continuous casting billet actually cut each time and the control fixed - length X, so that the length of the continuous casting billet cut by the fixed - length cutting system gradually approaches the control fixed - length, thereby improving the fixed - length qualified rate.

[0033] Further, the method for adjusting the parameters of the fixed - length cutting system according to the correction value b1 includes: calculating the correction value b1 = |Y1 - X|. If Y1 > X, adjust the parameters of the fixed - length cutting system to reduce the theoretical cutting length by b1. If Y1 < X, adjust the parameters of the fixed - length cutting system to increase the theoretical cutting length by b1.

[0034] It can be understood that if Y1 is too large, reduce the theoretical cutting length of the fixed - length cutting system, so that the length of the cut continuous casting billet is reduced and approaches the range [X - 0.005, X + 0.005]. If Y1 is too small, increase the theoretical cutting length of the fixed - length cutting system, so that the length of the cut continuous casting billet is reduced and approaches the range [X - 0.005, X + 0.005]. Due to the influence of factors such as the original position of the large vehicle of the flame cutting machine, the roller table, the thermal expansion coefficient of the continuous casting billet, and the section specifications, even if adjusted by the correction value, it still cannot be adjusted in place at one time and needs to be adjusted multiple times to make the length of the cut continuous casting billet gradually enter [X - 0.005, X + 0.005].

[0035] In some embodiments, the control fixed - length X is determined according to the required fixed - length L, the thermal expansion coefficient a, and the tolerance upper limit S: X = L×a+(S - 0.01), with the unit of m. This formula is an empirical formula obtained based on long - term data accumulation. Using the thermal expansion coefficient and the tolerance upper limit S to calculate the control fixed - length X enables the length of the high - temperature continuous casting billet produced to be within the range [L, L + S] after cooling to room temperature.

[0036] Further, the thermal expansion coefficient a is determined according to the round billet diameter and the drawing speed, and the specific values are shown in the following table:

[0037] Table 1 Thermal expansion coefficient value table

[0038] Round billet diameter (mm) Casting speed (m / min) Coefficient of thermal expansion 600 0.30-0.36 1.006 700 0.22-0.27 1.006 800 0.17-0.22 1.005 900 0.15-0.17 1.005 1000 0.13-0.15 1.004 1200 0.08-0.13 1.004

[0039] Furthermore, the thermal expansion coefficient a is corrected using a correction coefficient K, where K is a coefficient related to the ambient temperature.

[0040] The correction coefficient K takes values of K1, K2, and K3 at different temperatures, where K1 refers to the correction coefficient corresponding to an ambient temperature greater than 40°C, K2 refers to the correction coefficient corresponding to an ambient temperature between 10 and 40°C, and K3 refers to the correction coefficient corresponding to an ambient temperature less than 10°C. 1<K1≤1.005, 0.995≤K3<1, and K2=1

[0041] The thermal expansion coefficient a is determined according to the drawing speed and the round billet specifications, and is corrected by the correction coefficient, so that the value of the thermal expansion coefficient a is more accurate, which is conducive to improving the calculation accuracy of controlling the fixed length X, thereby improving the fixed length qualification rate.

[0042] Based on the above-mentioned method for adjusting parameters of the fixed-length cutting system, the present invention further provides a method for producing a continuous casting extra-large round billet, comprising:

[0043] Determine the required fixed length L and the acceptable tolerance range 0~S, calculate the thermal expansion coefficient a based on the specifications of the billet, the casting speed, and the required fixed length L, and calculate the controlled fixed length X based on the required fixed length L, the thermal expansion coefficient a, and the upper tolerance limit S;

[0044] Cut the ingot online, measure the length Y1 of the ingot No. 1, and determine whether X-0.005≤Y1≤X+0.005 is true. If not, calculate the correction value b1 and adjust the parameters of the cut-to-length system according to the correction value b1;

[0045] Repeat the above steps until the length of the billet n is Y n Satisfy X-0.005≤Y n ≤X+0.005, the parameter adjustment of the cut-to-length cutting system is completed;

[0046] Cut the ingot online using a cut-to-length system with adjusted parameters;

[0047] The ingot is placed in a slow cooling pit for slow cooling to room temperature.

[0048] Furthermore, the parameters of the cut-to-length system are adjusted starting from the second cast billet, that is, the second cast billet is cast billet No. 1.

[0049] It should be noted that the first billet is the head billet, which can be understood as the No. 0 billet. There is a dovetail groove on the head billet, and the laser sizing and dotting are inaccurate. Therefore, laser sizing is not enabled for the head billet. Instead, the encoder system is used for sizing. Therefore, the correction value is not calculated for the head billet.

[0050] Furthermore, each time before cutting the ingot online using the fixed-length cutting system with adjusted parameters, it is necessary to check that the original position to which the torch cutting machine carriage returns is always consistent.

[0051] It is understandable that when the original position to which the fire cutting machine carriage returns each time is always the same, the problem of needing to readjust the parameters of the cut-to-length cutting system due to position changes of the fire cutting machine carriage can be avoided.

[0052] After the slabs have cooled to room temperature, their length L0 is measured. The number of slabs with a length within the range L ≤ L0 ≤ L + S is counted as N0. The total number of slabs measured is N, and the cut-to-length pass rate is calculated as N0 / N. The cut-to-length pass rate can be used to determine whether the parameters of the current cut-to-length system are properly adjusted. If the cut-to-length pass rate is low, the flame-cutting machine carriage, roller table, thermal expansion coefficient a, and cut-to-length system should be inspected.

[0053] Furthermore, when measuring the ingot, the worst point on the cut surface is selected as the reference point for measurement. The poor cut surface needs to be sawed off with a sawing machine to ensure that a flat surface is left. To ensure a clean sawing, the worst point on the cut surface needs to be selected.

[0054] like Figure 2 The figure shows the qualified rate of the length of the extra-large round billet produced by the method of the present invention. The following is an illustration of several practical implementation plans:

[0055] Implementation Plan 1:

[0056] 1. According to the production plan, determine the customer demand specifications for the current production of round billets The pulling speed is 0.32m / min, the fixed length L is 6m, and the tolerance range accepted by the customer is 0~0.05m;

[0057] 2. Determine the expansion coefficient a = 1.006, the measurement environment temperature is 35 ° C, and take the correction coefficient K2 = 1; control the fixed length according to X = 6 × 1.006 + (0.05-0.01) = 6.076m, X + 0.005 = 6.081m, X-0.005 = 6.071m.

[0058] 3. Online cutting process of ingot:

[0059] (1) When the first ingot was cut online, the measured length was 6.09 m. Since the length of the first ingot was calculated according to the encoder data, the fixed-length cutting system was not used and it was not within the control tolerance range.

[0060] (2) When cutting the second ingot (i.e., ingot No. 1) online, the measured length Y1 = 6.053 m < 6.071 m, and the correction value of the laser scaling parameter b1 = 6.076 m - 6.053 m = 23 mm is adjusted;

[0061] (3) When cutting the third ingot online, the correction value 23 mm obtained from the second cutting is used to adjust the parameters, and the length of the third ingot is obtained as Y2 = 6.083 m. Since 6.083> 6.081, the correction value of the laser sizing parameter is adjusted to b2 = 6.083-6.076 = 7 mm;

[0062] (4) When the fourth ingot is cut online, the correction value of 7 mm obtained from the third cutting is used to adjust the parameters, and the length of the fourth ingot is obtained as Y4 = 6.077 m; 6.071 < 6.077 < 6.081, which meets the requirements, indicating that the fixed-length cutting system has been operating stably and meets production needs.

[0063] (5) After the ingots were cut online, they were lifted by a crane and placed in a slow cooling pit with an insulation cover for slow cooling for 48 hours. After the slow cooling was completed, they were taken out of the pit. After the ingots were cooled to room temperature, their lengths were measured. The measurement data were statistically analyzed. The number of ingots with a length within the range of L≤L0≤L+S was 159, the total number of ingots measured was 165, and the qualified rate of fixed length was 95.21%.

[0064] Implementation Plan 2:

[0065] 1. According to the production plan, determine the customer demand specifications for the current production of round billets The pulling speed is 0.16m / min, the fixed length L is 5m, and the tolerance range accepted by the customer is 0~0.05m;

[0066] 2. Determine the expansion coefficient a = 1.005, the measurement ambient temperature is 42 ° C, and take the correction coefficient K2 = 1.001; control the fixed length according to X = 5 × 1.005 × 1.001 + (0.05-0.01) = 5.07m, X + 0.005 = 5.075m, X-0.005 = 5.065m.

[0067] 3. Online cutting process of ingot:

[0068] (1) When the first ingot was cut online, the measured length was 5.10 m. Since the length of the first ingot was calculated according to the encoder data, the fixed-length cutting system was not used and it was not within the control tolerance range.

[0069] (2) When cutting the second ingot online, the measured length Y1 = 5.088m > 5.075m, and the correction value of the laser scaling parameter b1 = 5.088m - 5.07m = 18mm is adjusted;

[0070] (3) When cutting the third ingot online, the correction value 18 mm obtained from the second cutting was used to adjust the parameters, and the length of the third ingot was obtained as Y2 = 5.077 m. Since 5.077> 5.075, the correction value b2 of the laser sizing parameter was adjusted to 5.077-5.07 = 7 mm.

[0071] (4) When the fourth ingot is cut online, the correction value of 7 mm obtained from the third cutting is used to adjust the parameters, and the length of the fourth ingot is obtained as Y4 = 5.071 m; 5.065 < 5.071 < 5.075, which meets the requirements, indicating that the fixed-length cutting system has been operating stably and meets production needs.

[0072] (5) After the ingots were cut online, they were lifted by a crane and placed in a slow cooling pit with an insulation cover for slow cooling for 72 hours. After the slow cooling was completed, they were taken out of the pit. After the ingots were cooled to room temperature, their lengths were measured. The measurement data were statistically analyzed. The number of ingots with a length within the range of L≤L0≤L+S was 94, the total number of ingots measured was 98, and the qualified rate of fixed length was 95.92%.

[0073] Implementation Plan 3:

[0074] 1. According to the production plan, determine the customer demand specifications for the current production of round billets The pulling speed is 0.15m / min, the fixed length L is 4.6m, and the tolerance range accepted by the customer is 0~0.08m;

[0075] 2. Determine the expansion coefficient a = 1.004, the measurement ambient temperature is 6 ° C, and take the correction coefficient K2 = 0.998; control the fixed length according to X = 4.6 × 1.004 + (0.08-0.01) = 4.679m, X + 0.005 = 4.684m, X-0.005 = 4.674m.

[0076] 3. Online cutting process of ingot:

[0077] (1) When the first ingot was cut online, the measured length was 4.85m. Since the length of the first ingot was calculated according to the encoder data, the fixed-length cutting system was not used and it was not within the control tolerance range.

[0078] (2) When cutting the second ingot online, the measured length Y1 = 4.73m > 4.684m, and the correction value of the laser sizing parameter b1 = 4.73m - 4.679m = 51mm is adjusted;

[0079] (3) When cutting the third ingot online, the correction value of 51 mm obtained from the second cutting is used to adjust the parameters, and the length of the third ingot is obtained as Y2 = 4.688 m. Since 4.688> 4.684, the correction value of the laser sizing parameter is adjusted to b2 = 4.688-4.679 = 9 mm;

[0080] (4) When the fourth ingot is cut online, the correction value of 9 mm obtained from the third cutting is used to adjust the parameters, and the length of the fourth ingot is obtained as Y4 = 4.681 m; 4.674 < 4.681 < 4.684, which meets the requirements, indicating that the fixed-length cutting system has been operating stably and meets production needs.

[0081] (5) After the ingot is cut online, it is lifted by a crane and placed in a slow cooling pit with an insulation cover for slow cooling. The slow cooling time is 48 hours. After the slow cooling is completed, it is taken out of the pit. After the ingot is cooled to room temperature, its length is measured and the measurement data are counted. The number of ingots with a length within the range of L≤L0≤L+S is 36, the total number of ingots measured is 36, and the qualified rate of fixed length is 100%.

[0082] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A method for adjusting parameters of a cut-to-length cutting system, characterized in that: Including: Using a fixed-length cutting system to cut the first billet, measuring the length Y1 of the first billet in a high-temperature state, and determining whether X - 0.005 ≤ Y1 ≤ X + 0.005 holds. If not, adjust the parameters of the fixed-length cutting system according to the correction value b1, where X is the controlled fixed length and the correction value b1 is the difference between Y1 and X; Repeat the above steps until the length of the billet n is Y n Satisfy X-0.005≤Y n ≤X+0.005, the parameter adjustment of the fixed-length cutting system is completed.

2. The method for adjusting parameters of a cut-to-length cutting system according to claim 1, characterized in that: The method for adjusting the parameters of the fixed-length cutting system according to the correction value b1 includes: calculating the correction value b1 = |Y1 - X|. If Y1 > X, adjust the parameters of the fixed-length cutting system to reduce the theoretical cutting length by b1. If Y1 < X, adjust the parameters of the fixed-length cutting system to increase the theoretical cutting length by b1.

3. The method for adjusting parameters of a cut-to-length cutting system according to claim 1 or 2, characterized in that: The controlled fixed length X is determined according to the required fixed length L, the thermal expansion coefficient a, and the upper tolerance limit S: X = L×a + (S - 0.01).

4. The method for adjusting parameters of a cut-to-length cutting system according to claim 3, characterized in that: The thermal expansion coefficient a is determined according to the round billet diameter and the drawing speed.

5. The method for adjusting parameters of a cut-to-length cutting system according to claim 3, characterized in that: The thermal expansion coefficient a is corrected using a correction coefficient K, where K is a coefficient related to the ambient temperature.

6. A method for producing large round billets by continuous casting using the method for adjusting parameters of a cut-to-length cutting system according to any one of claims 1 to 5, characterized in that: Including: Determine the required fixed length L and the allowable tolerance range 0 to S, calculate the thermal expansion coefficient a according to the billet specifications, drawing speed, and required fixed length L, and calculate the controlled fixed length X according to the required fixed length L, thermal expansion coefficient a, and upper tolerance limit S; Cut the billet online, measure the length Y1 of the first billet, and determine whether X - 0.005 ≤ Y1 ≤ X + 0.005 holds. If not, calculate the correction value b1 and adjust the parameters of the fixed-length cutting system according to the correction value b1; Repeat the above steps until the length of the billet n is Y n Satisfy X-0.005≤Y n ≤X+0.005, the parameter adjustment of the cut-to-length cutting system is completed; Use the fixed-length cutting system with adjusted parameters to cut the billet online; Load the billet into a slow-cooling pit for slow cooling until it reaches room temperature.

7. The method for producing a continuous casting extra-large round billet according to claim 6, characterized in that: Start adjusting the parameters of the fixed-length cutting system from the second billet.

8. The method for producing a continuous casting extra-large round billet according to claim 6, characterized in that: Before each online cutting of the billet using the fixed-length cutting system with adjusted parameters, it is necessary to check that the original position returned by the large vehicle of the flame cutting machine is always the same.

9. The method for producing a continuous casting extra-large round billet according to claim 6, characterized in that: After the billet cools to room temperature, measure its length L0, count the number of billets with lengths in the range L ≤ L0 ≤ L + S as N0, measure the total number of billets as N, and calculate the fixed-length qualification rate = N0 / N.

10. The method for producing a continuous casting extra-large round billet according to claim 9, characterized in that: When measuring the billet, select the point at the worst position of the cutting surface as the measurement reference point.

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