A production allocation method for medium and heavy plate production line

Abstract

The present invention relates to the technical field of medium and thick plate rolling and provides a production allocation method for a medium and thick plate production line. The method comprises: S1, a heating process; and S2, a rolling process, wherein in step S1, a total amount of billets heated per unit time by multiple heating furnaces in the heating process is N1; and in step S2, a total amount of steel plates that can be rolled per unit time by a double-stand rolling mill in the rolling process is N2; and the relationship between N1 and N2 conforms to the formula N2-2<N1<N2+3. The method controls the billet heating capacity of the heating furnace to match the rolling rhythm of the double-stand rolling mill, thereby avoiding the situation where the rolling mill is idle and waiting for billets to be discharged from the furnace, thereby improving the production efficiency of the production line.

Description

Technical Field

[0001] The present invention relates to the technical field of medium and thick plate rolling, and in particular provides a production allocation method for a medium and thick plate production line. Background Art

[0002] In existing technologies, the production efficiency of medium and heavy plate production lines is affected by numerous factors, such as the heating capacity of heating furnaces and the rolling capacity of rolling mills. Many patents currently propose only improving the heating capacity of heating furnaces or the rolling capacity of rolling mills, but fail to provide effective methods for improving the production efficiency of the entire medium and heavy plate production line.

[0003] In the existing technology, there are many patents that optimize the heating efficiency of heating furnaces by optimizing the heating distribution method, such as patents CN102747216B, CN102435072A, CN107475507A, etc., by controlling the gap between steel billets in the heating furnace, laying out slabs in multiple layers, or using a walking beam heating furnace and a pusher heating furnace to share slabs.

[0004] Some patents also improve production efficiency by optimizing the rolling process, such as patent CN101658870A, which uses a method of changing the rolling process to improve the rolling mill rhythm, such as patent CN102896148B, which uses a method of optimizing the double-stand rolling load distribution to improve the rolling rhythm.

[0005] The technical solutions disclosed in the aforementioned patent documents for improving heating furnace efficiency or increasing the rolling mill's cadence only address efficiency improvements in the heating furnace or rolling mill, without considering the overall efficiency of the plate production line. The production efficiency of a plate production line is determined by both the heating capacity of the heating furnace and the rolling mill's capacity. Improving either the heating capacity of the heating furnace or the rolling mill's capacity alone will result in a mismatch between the heating furnace and rolling mill capacities, impacting the cadence and output of the entire production line. Summary of the Invention

[0006] To address the above issues, the present invention provides a process optimization solution that takes into account the overall performance of a medium and heavy plate production line. This solution can match the heating furnace capacity with the rolling mill capacity, and can also optimize the heating furnace process and the rolling mill process separately. The specific solution is as follows:

[0007] A production allocation method for a medium and thick plate production line, comprising:

[0008] S1, heating process;

[0009] S2, rolling process, wherein:

[0010] In step S1, the total amount of the blank heated per unit time by multiple heating furnaces is N1;

[0011] In step S2, the total amount of steel plates that can be rolled by the double-stand rolling mill per unit time is N2;

[0012] The relationship between N1 and N2 complies with the formula N2-2<N1<N2+3.

[0013] Furthermore, there are three heating furnaces, namely two first heating furnaces F1 and F2 and one second heating furnace F3. The first heating furnace is provided with two parallel walking beams; the second heating furnace is provided with three parallel walking beams; the total amount of blanks heated per unit time by the three heating furnaces is:

[0014] N1=N F1 +N F2 +N F3 =(2A1+2A2+2n+m+A3) / t;

[0015] Wherein, A1 is the number of rows of billets in the first heating furnace F1, A2 is the number of rows of billets in the first heating furnace F2; A3 is the number of rows of billets in the second heating furnace F3; t is the heating time in hours;

[0016] n is the number of rows in the second heating furnace for type a feeding method, where three blanks are fed in parallel at a time through three rows of walking beams;

[0017] m is the number of rows of type b distribution method in the second heating furnace. Type b distribution method is to feed two side-by-side blanks each time through three rows of walking beams, and the length of at least one blank needs to be erected by two rows of walking beams.

[0018] Furthermore, the blank includes two sizes: 220 mm and 320 mm in thickness.

[0019] Furthermore, the heating steps of the three heating furnaces in step S1 for the blank with a thickness of 320 mm include:

[0020] H1, preheating temperature ≤ 950℃, residence time ≥ 60min;

[0021] H2, heating section temperature is 950~980℃, residence time is ≥60min;

[0022] H3, heating section temperature is 1080~1110, residence time is ≥60min;

[0023] H4, heating section temperature is 1150~1180℃, residence time is ≥90min;

[0024] H5, soaking zone temperature is 1160~1200℃, residence time is ≥50min;

[0025] Total time ≥320 minutes;

[0026] The heating steps for a billet thickness of 220 mm include:

[0027] B1. Preheating temperature ≤ 950℃, residence time ≥ 40min;

[0028] B2. The temperature of the heating section is 950-980°C, and the residence time is ≥40min;

[0029] B3, the temperature of the heating section is 1080~1110, and the residence time is ≥40min;

[0030] B4, the temperature of the heating section is 1150~1180℃, and the residence time is ≥70min;

[0031] B5. The temperature of the soaking section is 1160-1200°C, and the residence time is ≥30 minutes;

[0032] Total time in the furnace ≥ 220min.

[0033] Furthermore, in step S2, the double-stand rolling mill includes a roughing mill and a finishing mill, wherein the roughing mill and the finishing mill both have an odd number of passes.

[0034] Furthermore, in step S2, the rolling force of the roughing mill and the finishing mill passes is ≥ rated rolling force × 70%, or the torque of the roughing mill and the finishing mill passes is ≥ rated torque × 70%.

[0035] Furthermore, in step S2, an instant cooling device is used to cool the intermediate billet between the roughing mill and the finishing mill passes.

[0036] Furthermore, in step S2, after the intermediate billet is finished in the roughing mill, the intermediate billet passes through the roughing mill instant cooling system. After cooling, the intermediate billet is transported to the finishing mill instant cooling system. During the transportation process, the intermediate billet is self-tempered and finally enters the roughing mill instant cooling system for cooling again.

[0037] Compared with the prior art, the advantages of the present invention are as follows:

[0038] 1. The present invention controls the heating quantity per unit time of the three heating furnaces to match the rolling quantity per unit time of the double-stand rolling mill, thereby avoiding the situation where the rolling mill is idle and waiting for the billet to be discharged from the furnace, thereby improving the production efficiency of the production line.

[0039] 2. The present invention adjusts the width value of the billet in the furnace and the number of rows heated by the two first heating furnaces, thereby adjusting the amount of billets heated per unit time in the two first heating furnaces; and adjusts the total number of billets heated in the third heating furnace by controlling the number of rows of the three distribution methods, thereby adjusting the amount of billets heated per unit time in the third heating furnace. By adjusting the amount of billets heated per unit time in the three heating furnaces, it matches the production capacity rhythm of the double-stand rolling mill.

[0040] 3. The present invention implements a five-stage heating and heat preservation process for billets of two specifications, 220mm and 320mm, in the walking beam continuous heating furnace. By selecting the specifications of the billet thickness, the residence time of the billets in multiple walking beam continuous heating furnaces is controlled, so that the discharge rhythm of the multiple walking beam continuous heating furnaces matches the rolling rhythm of the double-stand rolling mill.

[0041] 4. The present invention adopts the method of reducing the rolling time of each pass, reducing the total number of billet rolling passes, reducing the idle time of the roughing mill and the finishing mill waiting for each other, and reducing the intermediate billet waiting time, thereby greatly improving the rolling rhythm and rolling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a top view schematic diagram of the distribution method of the first walking beam type continuous heating furnace and the second walking beam type continuous heating furnace of the present invention. DETAILED DESCRIPTION

[0043] The technical solution of the invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the invention, rather than all of the embodiments.

[0044] Based on the embodiments of the invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the invention.

[0045] In the description of the invention, it should be noted that terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer" indicate positions or locations based on those shown in the accompanying drawings. These terms are intended solely to facilitate and simplify the description of the invention and are not intended to indicate or imply that the devices or components referred to have a specific orientation, be constructed, or operate in a specific manner. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0046] In the description of the invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the invention based on the specific circumstances.

[0047] Example 1

[0048] A production allocation method for a medium and thick plate production line, comprising:

[0049] Three heating furnaces, namely two first heating furnaces F1 and F2 and one second heating furnace F3, the first heating furnaces are provided with two parallel walking beams, and the second heating furnace is provided with three parallel walking beams;

[0050] The length of the first heating furnace and the second heating furnace are both L, and the maximum width of the blank is l max , the minimum width is l min , the number of rows of billets in the heating furnace is: L / l min ≧A≧L / l max , A takes the minimum value of the integer;

[0051] Then, let the number of rows of billets in the first heating furnace F1 be A1, the number of rows of billets in the first heating furnace F2 be A2, and the number of rows of billets in the second heating furnace F3 be A3;

[0052] The heating time of the two first heating furnaces F1 and F2 and the second heating furnace F3 is constant at t, where t is the heating time in hours.

[0053] Since there are two rows of walking beams in the first heating furnace, two side-by-side blanks can be fed in each time. The number of blanks that can be heated by the first heating furnace each time is 2A. The heating quantities per unit time of the two first heating furnaces are: N F1 =2A1 / t and N F2 =2A2 / t;

[0054] There are three rows of walking beams in the second heating furnace, and the feeding methods of the blanks are as follows:

[0055] a. Three rows of walking beams are used to feed three blanks side by side at a time;

[0056] b. Feed two blanks side by side at a time through three rows of walking beams, where at least one blank is long enough to be supported by two rows of walking beams;

[0057] c. Feed the blank one piece at a time through three rows of walking beams;

[0058] Assume that there are n rows of a type of distribution method, m rows of b type of distribution method, and f rows of c type of distribution method in the second heating furnace, f = A3-mn, then the number of blanks heated in the second heating furnace is 3n+2m+(A3-nm)=2n+m+A3, and the number of heats per unit time in the second walking beam continuous heating furnace is: N F3 =(2n+m+A3) / t;

[0059] Then the total amount of blanks heated by multiple heating furnaces per unit time is N1=N F1 +N F2 +N F3 =(2A1+2A2+2n+m+A3) / t, where t is the heating time in hours.

[0060] Preferably, two billets U1 and U2 are fed side by side into the first heating furnace for heating via two rows of walking beams. The lengths of the two billets U1 and U2 range from 2600 to 4800 mm, preferably 3300 mm, and the spacing between the two billets is 300 to 600 mm. The widths of the billets S1 and S2 can be selected from 1865, 2265, and 2665 mm, with a preferred width of 2265 mm. Each batch of the furnace can hold 20 rows, with an error of ±1 row, for a total of 40 ±2 billets. For a 220 mm thick billet, the furnace time is 220 minutes, meaning 10.9 ±2 billets can be removed per hour. For a 320 mm thick billet, the furnace time is 320 minutes, meaning 7.5 ±2 billets can be removed per hour.

[0061] The second step heating furnace is equipped with three parallel rows of walking beams, and its distribution method includes:

[0062] a. Each time, three billets A1, A2, and A3 are fed into the furnace for heating in parallel via three rows of walking beams. Each billet A1, A2, and A3 uses one row of walking beams. The length of A1, A2, and A3 ranges from 2600 to 3300 mm, preferably 3300 mm. The spacing between each row of billets is 300 to 600 mm. The width of the billets A1, A2, and A3 can be selected from 1865, 2265, and 2665 mm, with a preferred width of 2265 mm.

[0063] b1. Two billets V1 and V2 are fed side by side into a furnace for heating via three rows of walking beams. The lengths of billets V1 and V2 are too long for a single walking beam to transport. The two billets V1 and V2 are placed on the two outer walking beams, with the adjacent ends of billets V1 and V2 mounted on the middle walking beam. The lengths of billets V1 and V2 are both between 4800 and 5000 mm.

[0064] b2. Two billets C1 and C2 are fed into the furnace for heating side by side via three rows of walking beams. Billet C1 is twice the length of billet C2. During heating and conveying, C1 is placed on two adjacent rows of walking beams, and C2 is placed on another walking beam. The length of C1 is 5001-6599 mm, and the length of C2 is 2600-3300 mm. If billets C1 and C2 are fed continuously, the positions of C1 and C2 need to be swapped when feeding them next time.

[0065] d. Send a piece of billet D with a length that requires three rows of walking beams into the furnace for heating. The length of D is 6600~10000mm;

[0066] Table 1 Walking beam continuous heating furnace loading status

[0067]

[0068] The processing technology for blanks with a thickness of 320 mm includes:

[0069] The processing technology for the blank with a thickness of 320mm includes: H1, preheating section temperature ≤ 950℃, dwell time ≥ 60min; H2, heating section temperature 950-980℃, dwell time ≥ 60min; H3, heating section temperature 1080-1110℃, dwell time ≥ 60min; H4, heating section temperature 1150-1180℃, dwell time ≥ 90min; H5, soaking section temperature 1160-1200℃, dwell time ≥ 50min; total time ≥ 320min;

[0070] The processing technology for billet with thickness of 220mm includes: B1, preheating section temperature ≤950℃, residence time ≥40min; B2, heating section temperature is 950~980℃, residence time ≥40min; B3, heating section temperature is 1080~1110, residence time ≥40min; B4, heating section temperature is 1150~1180℃, residence time ≥70min; B5, soaking section temperature is 1160~1200℃, residence time ≥30min; total time in furnace ≥220min.

[0071] The total amount of billets heated per unit time by the multiple walking beam continuous heating furnaces is N1, and the residence time of the billets in the multiple walking beam continuous heating furnaces can be controlled by selecting the specifications of the billet thickness.

[0072] Double-stand rolling mill: the total amount of steel plates that can be rolled per unit time is N2;

[0073] The rolling process of the double-stand rolling mill is as follows: the steel biting speed of the roughing mill and the finishing mill are both ≥2.0m / s, and the acceleration is ≥1.5m / s 2The rolling speed of the roughing mill is 2-3 m / s, the rolling speed of the finishing mill is 3-6 m / s, the throwing distance of the roughing mill and the finishing mill is ≤1.0 m; the rolling force of the roughing mill and the finishing mill pass is ≥ the rated rolling force of the mill × 70%, or the torque of the roughing mill and the finishing mill pass is ≥ the rated torque of the mill × 70%; the number of passes of the roughing mill and the finishing mill are odd, and there is no empty pass; an instant cooling device is used between the passes of the roughing mill and the finishing mill to cool the intermediate billet to reduce the waiting time; the thickness of the steel plate after rolling the 220 mm billet is 10-100 mm, the thickness of the steel plate after rolling the 320 mm billet is 30-160 mm, and the thickness of 90% of the steel plates after rolling is between 15 and 100 mm.

[0074] An immediate cooling device is used between the roughing mill and the finishing mill to cool the intermediate billet. The cooling method is as follows: After the roughing mill, the intermediate billet passes through the roughing mill immediate cooling system at a speed of 0.5m / s to 5m / s. The roughing mill immediate cooling device is 6400mm long and 3500mm wide, with 8 sets of headers on each side. During cooling, the immediate cooling water pressure is 0.5MPa, the water flow rate of the upper header is 60-120m3 / h, and the water flow rate of the lower header is 120-240m3 / h, with a lower-to-upper water ratio of ≥2. After cooling, the intermediate billet is transported to the finishing mill immediate cooling system at a speed of 0.5m / s to 5m / s. During transportation, the intermediate billet is self-tempered. Before being transported to the immediate cooling system of the finishing mill, the intermediate billet passes through the immediate cooling system of the finishing mill at a speed of 0.5m / s to 5m / s. The immediate cooling device of the finishing mill is 4800mm long and 3500mm wide, with 6 sets of headers on the upper and lower sides. During cooling, the immediate cooling water pressure is 0.5MPa, and the water volume of the upper header is 60 to 120m 3 / h, the water volume of the lower header is 120~240m 3 / h, bottom to top water ratio ≥ 2. After the intermediate billet is cooled by the instant cooling device, the waiting time can be reduced and the rolling efficiency can be improved.

[0075] The above rolling process can reduce the rolling time of each pass, reduce the total number of billet rolling passes, reduce the idle time of the roughing mill and the finishing mill waiting for each other, and reduce the waiting time of the intermediate billet, thereby greatly improving the rolling rhythm and improving the rolling efficiency.

[0076] The relationship between N1 and N2 complies with the formula N2-2<N1<N2+3, so that the heating energy rhythm of multiple walking beam continuous heating furnaces matches the rolling rhythm of the double-stand rolling mill.

[0077] Example 2

[0078] Based on the solution of Example 1, taking batches 1 to 18 as an example, the present invention can achieve maximum production efficiency by matching the heating energy rhythm of multiple walking beam continuous heating furnaces with the rolling rhythm of the double-stand rolling mill in accordance with the formula N2-2<N1<N2+3.

[0079] The distribution mode, billet thickness, heating furnace discharge amount N1 and double-stand rolling mill rolling amount N2 of the two first-step beam continuous heating furnaces F1 and F2 and one second-step beam continuous heating furnace F3 are shown in Table 2.

[0080] Table 2 Heating furnace charging method, heating output and rolling mill rolling output

[0081]

[0082]

[0083] In batches 1 to 9, the relationship between the total heated output N1 and the total rolled output N2 conforms to the formula N2-2<N1<N2+3. The heating capacity of the heating furnace matches the rolling capacity of the rolling mill, and the production efficiency of the production line is maximized.

[0084] In batches 10 to 12, the charging methods, billet thickness, heating furnace discharge amount N1 and double-stand rolling mill rolling amount N2 of F1, F2 and F3 are shown in Table 3.

[0085] Table 3 Heating furnace charging method, heating output and rolling mill rolling output

[0086]

[0087] In batches 10 to 12, the relationship between the output of the heating furnace N1 and the rolling output of the rolling mill N2 is N1<N2-2, which means that the heating capacity of the heating furnace is less than the rolling capacity of the rolling mill. The heating capacity of the heating furnace is insufficient, and the double-stand rolling mill needs to wait and be idle during the rolling process. The heating capacity of the heating furnace does not match the production capacity rhythm of the double-stand rolling mill.

[0088] In batches 13 to 18, the charging methods, billet thickness, heating furnace discharge amount N1 and rolling mill rolling amount N2 of F1, F2 and F3 are shown in Table 4.

[0089] Table 4 Heating furnace charging method, heating output and rolling mill rolling output

[0090]

[0091]

[0092] In batches 13 to 18, the relationship between the total output N1 of the heating furnace and the total rolling output N2 is N1>N2+3, indicating that the heating capacity of the heating furnace is much greater than the rolling capacity of the double-stand rolling mill, and the heating furnace is overheated, which does not match the rolling capacity of the double-stand rolling mill.

[0093] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention 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. However, these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A production allocation method for a medium and thick plate production line, comprising: S1, heating process; S2, rolling process, wherein: In the step S1, the total amount of the blank heated per unit time by the plurality of heating furnaces is N1; In step S2, the total amount of steel plates that can be rolled by the double-stand rolling mill per unit time is N2; It is characterized in that There are three heating furnaces, namely two first heating furnaces F1 and F2 and one second heating furnace F3. The first heating furnaces are equipped with two parallel walking beams; the second heating furnace is equipped with three parallel walking beams. The total amount of blanks heated per unit time by the three heating furnaces is: <h2 style=";text-align:left;direction:ltr">N1=N<h2 style=";text-align:left;direction:ltr"> F1 <h2 style=";text-align:left;direction:ltr"> +N<h2 style=";text-align:left;direction:ltr"> F2 <h2 style=";text-align:left;direction:ltr"> +N<h2 style=";text-align:left;direction:ltr"> F3 <h2 style=";text-align:left;direction:ltr"> =(2A1+2A2+2n+m+A3) / t; Among them, N F1 N is the heating quantity per unit time of the first heating furnace; F2 is the heating quantity per unit time of the other first heating furnace; N F3 The heating quantity per unit time of a second heating furnace; A1 is the number of rows of billets in the first heating furnace F1, A2 is the number of rows of billets in the first heating furnace F2; A3 is the number of rows of billets in the second heating furnace F3; t is the heating time in hours; n is the number of rows in the second heating furnace for type a feeding method, where three blanks are fed in parallel at a time through three rows of walking beams; m is the number of rows in the second heating furnace for type b feeding method, in which two blanks are fed side by side at a time by three rows of walking beams, and at least one blank is long enough to be erected by two rows of walking beams; The relationship between N1 and N2 complies with the formula N2-2<N1<N2+3.

2. The production distribution method of the medium and thick plate production line according to claim 1, characterized in that: The blanks include two sizes: 220 mm and 320 mm in thickness.

3. The production distribution method of the medium and thick plate production line according to claim 2, characterized in that: The heating steps of the three heating furnaces in step S1 for the blank with a thickness of 320 mm include: H1, preheating temperature ≤ 950℃, residence time ≥ 60min; H2, heating section temperature is 950~980℃, residence time is ≥60min; H3, heating section temperature is 1080~1110, residence time is ≥60min; H4, heating section temperature is 1150~1180℃, residence time is ≥90min; H5, soaking zone temperature is 1160~1200℃, residence time is ≥50min; Total time ≥320 minutes; The heating steps for a billet thickness of 220 mm include: B1. Preheating temperature ≤ 950℃, residence time ≥ 40min; B2. The temperature of the heating section is 950-980°C, and the residence time is ≥40min; B3, the temperature of the heating section is 1080~1110, and the residence time is ≥40min; B4, the temperature of the heating section is 1150~1180℃, and the residence time is ≥70min; B5. The temperature of the soaking section is 1160-1200°C, and the residence time is ≥30 minutes; Total time in the furnace ≥ 220min.

4. The production distribution method of the medium and thick plate production line according to claim 1, characterized in that: In step S2, the double-stand rolling mill includes a roughing mill and a finishing mill, wherein the roughing mill and the finishing mill both have an odd number of passes.

5. The production distribution method of the medium and thick plate production line according to claim 4, characterized in that: In the step S2, the rolling force of the roughing mill and the finishing mill passes is ≥ rated rolling force × 70%, or the torque of the roughing mill and the finishing mill passes is ≥ rated torque × 70%.

6. The production distribution method of the medium and thick plate production line according to claim 5, characterized in that: In the step S2, an instant cooling device is used to cool the intermediate billet between the roughing mill and the finishing mill.

7. The production distribution method of the medium and thick plate production line according to claim 6, characterized in that: In step S2, after the intermediate billet is finished at the roughing mill, the intermediate billet is cooled by the roughing mill instant cooling system, and then the intermediate billet is transported to the finishing mill instant cooling system. During the transportation process, the intermediate billet is self-tempered and finally enters the finishing mill instant cooling system for further cooling.

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