A method for controlling the shape of pipeline steel plates with a width greater than 4200 mm

Abstract

This invention relates to the field of steel rolling technology, and more particularly to a method for controlling the shape of pipeline steel plates with a width greater than 4200mm, comprising: when rolling pipeline steel plates with a thickness of 21-27mm, the time for the third heating section and the soaking section is more than 120 minutes; when the thickness is greater than 27mm but not greater than 32mm, the time for the third heating section and the soaking section is more than 160 minutes, and the temperature of the soaking section is 1185-1230℃; the rolling cycle for pipeline steel plates with a thickness of 21-27mm is 1500-3000t; and for rolling plates with a thickness greater than 27mm but not greater than 32mm... The cycle is over 500t; the finishing mill passes for pipeline steel plates with a thickness of 21-32mm are 10-14; the thickness of the center area of ​​the steel plate is 0.03-0.12mm thinner than the edge; the width setting of the shielding value for pipeline steel plates with a thickness of 21-27mm is 4110-4550mm, and the width setting of the shielding value for thicknesses greater than 27mm but not greater than 32mm is 4345-4630mm; this invention can solve the plate shape control problem by simply adjusting the control parameters, which is low-cost, simple to operate, improves the steel plate yield, and reduces the rolling spot rate.

Description

Technical Field

[0001] This invention relates to the field of steel rolling technology, and in particular to a method for controlling the shape of pipeline steel plates with a width greater than 4200mm. Background Technology

[0002] Pipeline transportation is the most economical and rational method for transporting oil and natural gas. Long pipelines not only traverse regions with varying temperatures but also areas prone to geological movements caused by natural disasters such as earthquakes, frozen soil zones, mudslides, and landslides. Therefore, in addition to meeting high pressure and high toughness requirements, pipelines must also possess relatively high resistance to large deformations. Pipeline steel resistant to large deformations is one of the most challenging areas in pipeline steel development, requiring well-formed plates to ensure automated welding. Good plate shape facilitates wire cutting, transportation, and prevents equipment damage, ensuring on-time delivery. This is of paramount importance for the efficiency of pipeline steel processing and maintaining advanced manufacturing levels.

[0003] The current common method is to upgrade or modify the straightening machine or use a flattening machine. Both of these methods require a lot of manpower, resources and time, resulting in high processing costs. Furthermore, they have limited improvement effect on pipeline steel plates with a width greater than 4200mm.

[0004] In the prior art, patent application number 2009100760066.8 discloses a method for producing medium and heavy plates of X80 grade pipeline steel resistant to large deformation. The basic idea is that after two-stage rolling, the steel plate is air-cooled and relaxed to 30-50°C below the phase transformation temperature, and finally obtains a ferrite + bainite dual-phase structure. However, this method does not mention an effective plate shape control method. In addition, when the steel plate thickness is large, the required time is long, resulting in a significant reduction in production efficiency.

[0005] Patent application number 201010101105.8 discloses a low yield strength ratio X80 grade pipeline steel and its production method. The basic principle is to use ultra-fast cooling technology after rolling to cool the steel plate to the austenitic supercooled region, and then use a certain cooling rate to cool the steel plate to the target temperature. This invention application has the following characteristics: a) The invention uses a lot of alloys, such as Mo content of 0.22-0.32%, so the cost is high; b) The ultra-fast cooling technology used is difficult to control in actual production, especially as the thickness of the steel plate increases, the temperature difference between the surface and the core of the steel plate will be large, which will have a certain impact on the strength and toughness of the steel plate, the product quality is unstable, and it is not suitable for mass production. In addition, this method does not mention an effective plate shape control method.

[0006] The patent application CN201210327206 discloses a deformation-resistant X80-X100 deformable steel plate and its manufacturing method. Its basic idea is similar to that of application 2009100760066.8, that is, the steel plate is first cooled to the two-phase region by air cooling relaxation. Since both use air cooling relaxation, the production efficiency will be affected by the long air cooling time, especially when the wall thickness is thick. Neither of these two methods mentions an effective plate shape control method. Summary of the Invention

[0007] This invention provides a method for controlling the shape of pipeline steel plates with a width greater than 4200mm. The plate shape control problem can be solved simply by adjusting the control parameters. It does not require a large investment in software and hardware costs, and the requirements for relevant technical personnel are not high. It improves the steel plate yield and reduces the rolling spot rate.

[0008] To achieve the above objectives, the present invention employs the following technical solution:

[0009] A method for controlling the shape of pipeline steel plates with a width greater than 4200mm, the method specifically includes the following:

[0010] 1) When rolling pipeline steel plates with a thickness of 21-27mm, the time for the third heating section and the soaking section should be more than 120 minutes. When the thickness is greater than 27mm but not greater than 32mm, the time for the third heating section and the soaking section should be more than 160 minutes, and the temperature of the soaking section should be 1185-1230℃. When the billet reaches the soaking section, adjust the temperature difference between the upper and lower surfaces of the billet in the heating furnace. The target temperature difference should be 25-35℃.

[0011] 2) The rolling cycle for pipeline steel plates with a thickness of 21-27mm is 1500-3000t, and the rolling cycle for pipeline steel plates with a thickness greater than 27mm but not greater than 32mm is more than 500t.

[0012] 3) For pipeline steel plates with a thickness of 21-32mm, the corresponding finishing mill passes are 10-14.

[0013] 4) The thickness of the steel plate in the center area is 0.03 to 0.12 mm thinner than that at the edges;

[0014] 5) Determine the original width setting of various specifications. For pipeline steel plates with a thickness of 21-27mm, set the width setting to 4110-4550mm. For specifications with a thickness greater than 27mm but not greater than 32mm, set the width setting to 4345-4630mm.

[0015] Furthermore, in the rolling cycle, a maximum of 160 plates are arranged in each rolling cycle. Pipeline steel plates with a thickness greater than 27mm and not greater than 32mm are arranged first, followed by pipeline steel plates with a thickness of 21 to 27mm.

[0016] Furthermore, in the process of determining the original width setting occlusion value for various specifications, the width setting occlusion value is adjusted in units of 20 to 50 mm.

[0017] Furthermore, it also includes determining the CVC roll values ​​for various specifications of finishing mills. During the determination process, the CVC roll values ​​for finishing mills are controlled by adjusting the rolls by 8-19 mm with a rolling force deviation of 150-200t.

[0018] Furthermore, during the process of determining the shielding values ​​for the original width of various specifications, the water flow rate is increased by 10-15m³ for every 2-3°C increase in water temperature, based on the laminar flow water temperature variation. 3 / h, otherwise reduce by 10-15m. 3 / h.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1) This invention utilizes existing equipment and process conditions, without increasing investment and production costs or the risk of equipment damage, while improving production efficiency, thus achieving cost reduction and efficiency improvement;

[0021] 2) This invention can solve the plate shape control problem simply by adjusting the control parameters, without requiring a large investment in software and hardware costs, and does not require highly skilled personnel. It is a control method that improves the steel plate yield and reduces the rolling spot rate.

[0022] 3) The method of this invention increases the plate shape qualification rate from 34.2% to 90.2%;

[0023] 4) The rolling process of this invention is stable and smooth, and the plate shape is good after being placed on the cooling bed. It can be successfully applied to the rolling of ultra-wide pipeline steel in TMCP state and the stable mass production of ultra-wide bridge steel Q500qE. It has wide applicability and can be successfully applied to existing 5-meter rolling mill production lines in China. Detailed Implementation

[0024] The specific embodiments of the present invention will be further described below:

[0025] This invention discloses a method for controlling the shape of pipeline steel plates with a width greater than 4200mm, which is particularly suitable for producing pipeline steel with a thickness ≥21mm and a width >4200mm. The specific control method includes the following:

[0026] 1) Prioritize ensuring the time spent in the third heating section and the soaking section in the furnace: When rolling pipeline steel plates with a thickness of 21-27mm, the time in the third heating section and the soaking section should be more than 120 minutes. When the thickness is greater than 27mm but not greater than 32mm, the time in the third heating section and the soaking section should be more than 160 minutes. The temperature of the soaking section should be 1185-1230℃. When the billet reaches the soaking section, adjust the temperature difference between the upper and lower surfaces of the billet in the heating furnace. The target temperature difference should be 25-35℃ to prevent warping.

[0027] 2) Ensure a reasonable rolling cycle: The rolling cycle for pipeline steel plates with a thickness of 21-27mm is 1500-3000t, and the rolling cycle for pipeline steel plates with a thickness greater than 27mm but not greater than 32mm is more than 500t. In order to make full use of the rolls, pipeline steel plates with a thickness greater than 27mm but not greater than 32mm are scheduled first, followed by pipeline steel plates with a thickness of 21-27mm. A maximum of 160 pieces are scheduled per rolling cycle. In the production plan, when switching between specifications, transition plates are used for transition rolling to prevent the rolls from peeling.

[0028] 3) Different rolling passes correspond to different roll gaps and plate shapes. Therefore, fixed rolling passes are used to reduce variable conditions and provide a basis for precise control of plate shape. For pipeline steel plates with a thickness of 21-32mm, the finishing mill passes are 10-14. If the intermediate billet of the roughing mill curls up, the image separation method is used to add a leveling pass to ensure safe biting of the finishing mill.

[0029] 4) In the final pass of the finishing mill, the thickness of the steel plate in the center area is controlled with slight center waviness, and the thickness of the steel plate in the center area is 0.03 to 0.12 mm thinner than that at the edge.

[0030] 5) Determine the original width and set the shielding value for each specification. For pipeline steel plates with a thickness of 21-27mm, set the shielding value to 4110-4550mm. For specifications with a thickness of 32mm or greater than 27mm but not greater than 32mm, set the shielding value to 4345-4630mm. Adjust the width setting shielding value in units of 20-50mm. For the finishing mill CVC roll setting, the control principle is to adjust the roll setting by 8-19mm for every 150-200t rolling force deviation. According to the laminar flow water temperature change, increase the water supply by 10-15m³ for every 2-3℃ increase in water temperature. 3 / h, otherwise reduce by 10-15m. 3 / h.

[0031] The following embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments. Unless otherwise specified, the methods used in the following embodiments are conventional methods.

[0032] Example 1:

[0033] The billet thickness is 300mm, and the produced steel plate is 22*4580mm. The specific control method is as follows:

[0034] 1) Priority should be given to ensuring the time spent in the third heating section and the soaking section: the time in the third heating section and the soaking section should be more than 128 minutes, the soaking temperature should be 1185~1220℃, and the temperature difference between the upper and lower surfaces of the billet in the heating furnace should be adjusted. When the billet reaches the soaking section, the temperature difference between the upper and lower surfaces of the billet in the heating furnace should be adjusted to a target value of 26℃ to prevent warping.

[0035] 2) The rolling cycle for pipeline steel plates with a thickness of 21-27mm is 1500-3000t, and the rolling cycle for pipeline steel plates with a thickness greater than 27mm but not greater than 32mm is more than 500t. In order to make full use of the rolling rolls, the production of 32mm pipeline steel plates is scheduled first, followed by the production of 21-27mm pipeline steel plates. A maximum of 160 pieces are scheduled per rolling roll cycle. In the production schedule, when switching between specifications, a transition plate is used for transition rolling to prevent the rolling rolls from peeling.

[0036] 3) Different rolling passes correspond to different roll gaps and plate shapes. Therefore, fixed rolling passes are used to reduce variable conditions and provide a basis for precise control of plate shape. The 22mm specification finishing mill corresponds to 12 passes. If the intermediate billet of the roughing mill curls up, the image separation method is used to add a leveling pass to ensure safe biting of the finishing mill.

[0037] 4) In the final pass of the finishing mill, the thickness of the steel plate in the center area is controlled with slight center waviness, and the thickness of the center area is 0.03 to 0.07 mm thinner than that of the edge area.

[0038] 5) Determine the original width setting shielding value for various specifications. For 22mm thickness specifications, the set shielding value is 4210-4550mm, with adjustments in 23mm increments. The CVC roll setting for the finishing mill is controlled by adjusting the roll setting by 10mm for every 160t rolling force deviation. Based on the laminar flow water temperature change, increase the water supply by 10m³ for every 2℃ increase in water temperature. 3 / h, otherwise reduce by 10m 3 / h.

[0039] 6) The method of this invention increases the pass rate of steel plate shape of this specification from 34.2% to 90.8%.

[0040] Example 2:

[0041] The billet thickness is 300mm, and the produced steel plate is 26*4680mm. The specific control method is as follows:

[0042] 1) Priority should be given to ensuring the time spent in the third heating section and the soaking section in the furnace. The time in the third heating section and the soaking section should be more than 178 minutes, and the soaking temperature should be 1185~1220℃. Adjust the temperature difference between the upper and lower surfaces of the billet in the heating furnace. When the billet reaches the soaking section, adjust the temperature difference between the upper and lower surfaces of the billet in the heating furnace. The target value is 31℃ to prevent warping.

[0043] 2) Ensure a reasonable rolling cycle for the rolls. The rolling cycle for 32mm rolls is over 500t. To make full use of the rolls, 32mm rolls can be rolled first, followed by 21-27mm rolls. A maximum of 160 rolls can be rolled per roll cycle. When switching between specifications, a transition plate should be used for transition rolling to prevent the rolls from peeling.

[0044] 3) Different rolling passes correspond to different roll gaps and plate shapes. Therefore, fixed rolling passes are used to reduce variable conditions and provide a basis for precise control of plate shape. The 26mm specification finishing mill corresponds to 14 passes. If the intermediate billet of the roughing mill curls up, the image separation method is used to add a leveling pass to ensure safe biting of the finishing mill.

[0045] 4) For the final pass of the finishing mill, the thickness of the steel plate in the center area should be controlled to be slightly thinner than that at the edge, with a slight central waviness.

[0046] 5) Determine the original width setting shielding value for various specifications. For 26mm thickness specifications, set the width shielding value to 4350-4550mm, adjusting in 28mm increments. For the finishing mill CVC roll setting, the control principle is to adjust the roll setting by 13mm for every 200t rolling force deviation. Based on the laminar flow water temperature change, increase the water supply by 12m³ for every 2℃ increase in water temperature. 3 / h, otherwise reduce by 12m 3 / h.

[0047] 6) The method of this invention increases the pass rate of steel plate shape of this specification from 74.2% to 91.7%.

[0048] Example 3:

[0049] The billet thickness is 300mm, and the produced steel plate is 30*4680mm. The specific control method is as follows:

[0050] 1) Priority should be given to ensuring the time spent in the third heating section and the soaking section in the furnace. The time in the third heating section and the soaking section should be more than 178 minutes, and the soaking temperature should be 1185~1220℃. Adjust the temperature difference between the upper and lower surfaces of the billet in the heating furnace. When the billet reaches the soaking section, adjust the temperature difference between the upper and lower surfaces of the billet in the heating furnace. The target value is 32℃ to prevent warping.

[0051] 2) Ensure a reasonable rolling cycle for the rolls. The rolling cycle for 32mm rolls is over 500t. To make full use of the rolls, 32mm rolls can be rolled first, followed by 21-31mm rolls. A maximum of 160 rolls can be rolled per roll cycle. When switching between specifications, a transition plate should be used for transition rolling to prevent the rolls from peeling.

[0052] 3) Different rolling passes correspond to different roll gaps and plate shapes. Therefore, fixed rolling passes are used to reduce variable conditions and provide a basis for precise control of plate shape. The 30mm specification finishing mill corresponds to 14 passes. If the intermediate billet of the roughing mill curls up, the image separation method is used to add a leveling pass to ensure safe biting of the finishing mill.

[0053] 4) For the final pass of the finishing mill, the thickness of the steel plate in the center area should be controlled with slight center waviness, and the thickness of the steel plate in the center area should be 0.08 to 0.12 mm thinner than that at the edge.

[0054] 5) Determine the original width setting shielding value for various specifications. For 30mm thickness specifications, the set shielding value is 4350-4610mm, with adjustments in 31mm increments. The CVC roll setting for the finishing mill is controlled by adjusting the roll setting by 14mm for every 200t rolling force deviation. Based on the laminar flow water temperature change, increase the water supply by 13m³ for every 2℃ increase in water temperature. 3 / h, otherwise reduce by 13m 3 / h.

[0055] 6) The method of this invention increases the pass rate of steel plate shape of this specification from 78.12% to 93.17%.

[0056] Example 4:

[0057] The billet thickness is 300mm, and the produced steel plate is 32*4680mm. The specific control method is as follows:

[0058] 1) Priority should be given to ensuring the time spent in the third heating section and the soaking section in the furnace. The time in the third heating section and the soaking section should be more than 178 minutes, and the soaking temperature should be 1185~1220℃. Adjust the temperature difference between the upper and lower surfaces of the billet in the heating furnace. When the billet reaches the soaking section, adjust the temperature difference between the upper and lower surfaces of the billet in the heating furnace. The target value is 35℃ to prevent warping.

[0059] 2) Ensure a reasonable rolling cycle for the rolls. The rolling cycle for 32mm rolls is over 500t. To make full use of the rolls, 32mm rolls can be rolled first, followed by 21-27mm rolls. A maximum of 160 rolls can be rolled per roll cycle. When switching between specifications, a transition plate should be used for transition rolling to prevent the rolls from peeling.

[0060] 3) Different rolling passes correspond to different roll gaps and plate shapes. Therefore, fixed rolling passes are used to reduce variable conditions and provide a basis for precise control of plate shape. The 32mm specification finishing mill corresponds to 14 passes. If the intermediate billet of the roughing mill curls up, the image separation method is used to add a leveling pass to ensure safe biting of the finishing mill.

[0061] 4) For the final pass of the finishing mill, the thickness of the steel plate in the center area should be controlled with slight center waviness, and the thickness of the steel plate in the center area should be 0.08 to 0.12 mm thinner than that at the edge.

[0062] 5) Determine the original width setting shielding value for various specifications. For 32mm thickness specifications, the set shielding value is 4350-4650mm, with adjustments in 31mm increments. The CVC roll setting for the finishing mill is controlled by adjusting the roll setting by 15mm for every 200t rolling force deviation. Based on the laminar flow water temperature change, increase the water supply by 15m³ for every 2℃ increase in water temperature. 3 / h, otherwise reduce by 15m 3 / h.

[0063] 6) The method of this invention increases the pass rate of steel plate shape of this specification from 85.12% to 96.26%.

Claims

1. A method for controlling the shape of pipeline steel plates with a width greater than 4200mm, characterized in that, The method specifically includes the following: 1) When rolling pipeline steel plates with a thickness of 21-27mm, the time for the third heating section and the soaking section should be more than 120 minutes. When the thickness is greater than 27mm but not greater than 32mm, the time for the third heating section and the soaking section should be more than 160 minutes, and the temperature of the soaking section should be 1185-1230℃. When the billet reaches the soaking section, adjust the temperature difference between the upper and lower surfaces of the billet in the heating furnace. The target temperature difference should be 25-35℃. 2) The rolling cycle for pipeline steel plates with a thickness of 21-27mm is 1500-3000t, and the rolling cycle for pipeline steel plates with a thickness greater than 27mm but not greater than 32mm is more than 500t. 3) For pipeline steel plates with a thickness of 21-32mm, the corresponding finishing mill passes are 10-14. 4) The thickness of the steel plate in the center area is 0.03 to 0.12 mm thinner than that at the edges; 5) Determine the original width setting shielding value for various specifications. The shielding value for the width of pipeline steel plates with a thickness of 21-27mm is 4110-4550mm, and the shielding value for the width of specifications with a thickness greater than 27mm but not greater than 32mm is 4345-4630mm.

2. The method for controlling the shape of pipeline steel plates with a width greater than 4200mm according to claim 1, characterized in that, In the rolling mill cycle, a maximum of 160 plates are arranged in each rolling mill cycle. Pipeline steel plates with a thickness greater than 27mm and not greater than 32mm are arranged first, followed by pipeline steel plates with a thickness of 21 to 27mm.

3. The method for controlling the shape of pipeline steel plates with a width greater than 4200mm according to claim 1, characterized in that, In the process of determining the original width setting occlusion value for various specifications, the width setting occlusion value is adjusted in units of 20 to 50 mm.

4. The method for controlling the shape of pipeline steel plates with a width greater than 4200mm according to claim 1, characterized in that, It also includes determining the CVC roll values ​​for various specifications of finishing mills. During the determination process, the CVC roll values ​​for finishing mills are controlled by adjusting the rolls by 8-19 mm with a rolling force deviation of 150-200t.

5. The method for controlling the shape of pipeline steel plates with a width greater than 4200mm according to claim 1, characterized in that, In determining the shielding values ​​for the original widths of various specifications, the water flow rate is increased by 10-15m³ for every 2-3°C increase in laminar water temperature. 3 / h, otherwise reduce by 10-15m. 3 / h.