Control method for shape of pipeline steel plate with width larger than 4200 mm

Abstract

The invention relates to the technical field of steel rolling, in particular to a control method for the shape of a pipeline steel plate with the width larger than 4200 mm. The control method comprises the steps that when the pipeline steel plate with the thickness of 21-27 mm is rolled, the time of a third heating section and a soaking section is 120 min or above, when the thickness is larger than 27 mm and not larger than 32 mm, the time of the third heating section and the soaking section is 160 min or above, and the temperature of the soaking section is 1185-1230 DEG C; the rolling period of the pipeline steel plate with the thickness specification of 21-27 mm is 1500-3000 t, and the rolling period of the pipeline steel plate with the thickness larger than 27 mm and not larger than 32 mm is 500 t or above; the pass number of a finishing mill corresponding to the pipeline steel plate with the thickness specification of 21-32 mm is 10-14; the thickness of the central area of the steel plate is 0.03-0.12 mm thinner than that of the edge part; the shielding value of the width of the pipeline steel plate with the thickness of 21-27 mm is set to be 4110-4550 mm, and the shielding value of the width of the pipeline steel plate with the thickness larger than 27 mm and not larger than 32 mm is set to be 4345-4630 mm; the problem of plate shape control can be solved only by adjusting control parameters, the cost is low, the operation is simple, the steel plate yield is improved, and the rolling spot rate is reduced.

Description

Technical Field

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

[0002] Pipeline transportation is the most economical and efficient method for transporting oil and natural gas. Long pipelines not only pass through varying temperature zones but also through areas subject to ground movement caused by earthquakes, permafrost, debris flows, landslides, and other natural disasters. Therefore, pipelines must not only meet high pressure and toughness requirements but also possess relatively high resistance to large deformation. Deformation-resistant pipeline steel is one of the most challenging areas of pipeline steel development, requiring excellent plate shape to ensure automated welding. This excellent shape facilitates shearing and transportation, prevents damage to equipment, and ensures contractual delivery dates. This is crucial for the profitability of pipeline steel processing and maintaining advanced manufacturing standards.

[0003] The general method now is to solve it by upgrading the straightening machine or by using a flattening machine. Both methods will cost a lot of manpower, material resources and time, have high processing costs, and have limited improvement effects on the shape of pipeline steel plates with a width greater than 4200mm.

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

[0005] Patent application number 201010101105.8 discloses a low-yield ratio X80 grade pipeline steel and a production method thereof. The basic principle of the invention is to use ultra-fast cooling technology after rolling to cool the steel plate to the austenite supercooling zone, and then use a certain cooling rate to cool the steel plate to the target temperature; the invention application has the following characteristics: a) the invention uses a large number of alloys, such as a Mo content of 0.22-0.32%, which results in a high cost; b) the ultra-fast cooling technology used has certain difficulties in actual production control, especially as the thickness of the steel plate increases, the temperature of the steel plate surface and the core will differ greatly, which has a certain impact on the strength and toughness of the steel plate, and the product quality is unstable, which is not suitable for mass production, and this method does not mention an effective plate shape control method.

[0006] Patent application number CN201210327206 discloses deformation-resistant X80-X100 deformed steel plates and their manufacturing methods. The basic concept is similar to that of patent application number 2009100760066.8, that is, the steel plates are first cooled to the two-phase region by the air cooling relaxation method. Since both methods use the air cooling relaxation method, the production efficiency will be affected due to 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] The present invention provides a method for controlling the shape of pipeline steel plates with a width greater than 4200 mm. The shape control problem can be solved by simply adjusting the control parameters, without investing large software and hardware costs. At the same time, the requirements for relevant technical personnel are not high, the steel plate yield rate is improved, and the rolling spot rate is reduced.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

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

[0010] 1) When rolling pipeline steel plates with a thickness of 21-27 mm, the third heating section and soaking section should last for more than 120 minutes. When the thickness is greater than 27 mm and not greater than 32 mm, the third heating section and soaking section should last for more than 160 minutes, and the soaking section temperature should be 1185-1230°C. When the billet arrives at the soaking section, the temperature difference between the upper and lower surfaces of the heating furnace should be adjusted, with a target temperature difference of 25-35°C.

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

[0012] 3) The finishing mill passes corresponding to pipeline steel plates with thickness specifications of 21 to 32 mm are 10 to 14 passes;

[0013] 4) The thickness of the central area of ​​the steel plate is 0.03 to 0.12 mm thinner than that of the edge;

[0014] 5) Determine the masking value of the original width setting for various specifications. The masking value of the width setting for pipeline steel plates with a thickness of 21 to 27 mm is 4110 to 4550 mm. The masking value of the width setting for specifications with a thickness greater than 27 mm and not greater than 32 mm is 4345 to 4630 mm.

[0015] Furthermore, in the rolling cycle, a maximum of 160 pieces are produced in each rolling cycle, and pipeline steel plates with a thickness greater than 27 mm and not greater than 32 mm are produced first, and then pipeline steel plates with a thickness specification of 21 to 27 mm are produced.

[0016] Furthermore, in the process of determining the original width setting shielding values ​​of various specifications, the width setting shielding value is adjusted with 20 to 50 mm as an adjustment unit.

[0017] Furthermore, it also includes determining the CVC roll string values ​​of various specifications of finishing mills. During the determination process, the CVC roll string value of the finishing mill is controlled by the rolling force deviation of 150 to 200 tons and the roll string is adjusted by 8 to 19 mm.

[0018] Furthermore, in the process of determining the original width of various specifications and setting the shielding value, according to the change of laminar water temperature, the water supply volume is increased by 10 to 15 m for every 2 to 3 ° C increase in water temperature. 3 / h, otherwise reduce by 10-15m 3 / h.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1) The present invention utilizes existing equipment and process conditions, which neither increases investment and production costs nor increases the risk of equipment damage, while improving production efficiency and achieving cost reduction and efficiency improvement;

[0021] 2) The present invention can solve the plate shape control problem by simply adjusting the control parameters, without investing large software and hardware costs, and at the same time, the requirements for relevant technical personnel are not high, and the control method improves the steel plate yield rate and reduces the rolling spot rate;

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

[0023] 4) The rolling process of the method of the present 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 TMCP state ultra-wide pipeline steel and the stable large-scale production of ultra-wide bridge steel Q500qE. It has wide promotion potential and can be successfully applied to existing domestic 5-meter rolling mill production lines. DETAILED DESCRIPTION

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

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

[0026] 1) Prioritize the time that the third heating section and soaking section spend in the furnace: When rolling pipeline steel plates with a thickness of 21 to 27 mm, the time of the third heating section and soaking section is more than 120 minutes. When the thickness is greater than 27 mm and not greater than 32 mm, the time of the third heating section and soaking section is more than 160 minutes. The soaking section temperature is 1185 to 1230°C. When the billet arrives at the soaking section, adjust the temperature difference between the upper and lower surfaces of the heating furnace slab. The target temperature difference is 25 to 35°C to prevent warping.

[0027] 2) Ensure a reasonable rolling cycle: The rolling cycle of pipeline steel plates with a thickness of 21 to 27 mm is 1500 to 3000 t, and the rolling cycle of pipeline steel plates with a thickness greater than 27 mm and not greater than 32 mm is more than 500 t. In order to make full use of the rolling rolls, pipeline steel plates with a thickness greater than 27 mm and not greater than 32 mm are scheduled for production first, and then pipeline steel plates with a thickness of 21 to 27 mm are scheduled for production. A maximum of 160 pieces are scheduled for each rolling cycle. In the production schedule, when switching specifications, transition plates are used for transition rolling in the middle to prevent the rollers 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 basic conditions for precise control of plate shape. The finishing mill passes corresponding to pipeline steel plates with a thickness of 21 to 32 mm are 10 to 14 passes. If the intermediate slab of the roughing mill warps, the image separation method is used to add a flattening pass to ensure safe biting of the finishing mill.

[0029] 4) The final pass of the finishing mill is controlled according to a slight center wave, and the thickness of the center area of ​​the steel plate is 0.03 to 0.12 mm thinner than the edge.

[0030] 5) Determine the original width setting masking values ​​for various specifications. The width setting masking values ​​for pipeline steel plates with a thickness of 21 to 27 mm are 4110 to 4550 mm. The width setting masking values ​​for specifications with a thickness of 32 mm, which is greater than 27 mm but not greater than 32 mm, are 4345 to 4630 mm. The width setting masking values ​​are adjusted with 20 to 50 mm as an adjustment unit. The CVC string roller value of the finishing mill is controlled by the rolling force deviation of 150 to 200 t and the string roller adjustment of 8 to 19 mm. According to the change of laminar water temperature, the water supply volume is increased by 10 to 15 m for every 2 to 3 ° C increase in water temperature. 3 / h, otherwise reduce by 10-15m 3 / h.

[0031] The following examples are implemented under the premise of the technical solution of the present invention, and provide detailed implementation methods and specific operating processes, but the scope of protection of the present invention is not limited to the following examples. The methods used in the following examples are conventional methods unless otherwise specified.

[0032] Example 1:

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

[0034] 1) Priority should be given to ensuring that the third heating section and soaking section are in the furnace for more than 128 minutes, with a soaking temperature of 1185-1220°C. The temperature difference between the upper and lower surfaces of the slab 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 slab in the heating furnace should be adjusted to a target value of 26°C to prevent warping.

[0035] 2) The rolling cycle of pipeline steel plates with thickness specifications of 21 to 27 mm is 1500 to 3000 t, and the rolling cycle of pipeline steel plates with thickness specifications greater than 27 mm and not greater than 32 mm is more than 500 t. In order to make full use of the rolling rolls, 32 mm pipeline steel plates are scheduled for production first, and then 21 to 27 mm pipeline steel plates are scheduled for production. A maximum of 160 pieces are scheduled for each rolling cycle. In the production schedule, when switching production specifications, transition plates are used for transition rolling in the middle to prevent the rollers 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 basic conditions for precise control of plate shape. The 22mm specification finishing mill corresponds to 12 passes. If the intermediate slab of the roughing mill is warped, the image separation method is used to add a flattening pass to ensure safe biting of the finishing mill.

[0037] 4) The final pass of the finishing mill is controlled according to a slight center wave, and the thickness of the center area of ​​the steel plate is 0.03 to 0.07 mm thinner than the edge.

[0038] 5) Determine the original width setting masking value of various specifications. The width setting masking value of 22mm thickness specification is 4210~4550mm, and the adjustment is made in 23mm units. The CVC roller stringing value of the finishing mill is controlled by the rolling force deviation of 160t and the roller stringing is adjusted by 10mm. According to the change of laminar water temperature, the water supply volume is increased by 10m for every 2℃ increase in water temperature. 3 / h, otherwise reduce 10m 3 / h.

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

[0040] Example 2:

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

[0042] 1) Priority should be given to ensuring that the third heating section and soaking section are in the furnace for more than 178 minutes, and the soaking temperature is 1185-1220°C. The temperature difference between the upper and lower surfaces of the slab 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 slab in the heating furnace should be adjusted, with a target value of 31°C, to prevent warping.

[0043] 2) Ensure a reasonable rolling cycle of the rolls. The rolling cycle of 32mm rolls is more than 500t. In order to make full use of the rolls, 32mm rolls can be arranged first, and then 21-27mm rolls. A maximum of 160 rolls can be arranged in each roll cycle. When switching specifications, transition plates are used in the middle 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 basic conditions for precise control of plate shape. The 26mm specification finishing mill corresponds to 14 passes. If the intermediate slab of the roughing mill is warped, the image separation method is used to add a flattening pass to ensure safe biting of the finishing mill.

[0045] 4) The final pass of the finishing mill is controlled according to a slight center wave, and the thickness of the center area of ​​the steel plate is preferably 0.08 to 0.12 mm thinner than the edge.

[0046] 5) Determine the original width setting shielding value of various specifications. The shielding value of the 26mm thickness specification width is set to 4350~4550mm, and the adjustment is made in 28mm units. The CVC roller stringing value of the finishing mill is controlled by the rolling force deviation of 200t and the roller stringing is adjusted by 13mm. According to the change of laminar water temperature, the water supply volume is increased by 12m for every 2℃ increase in water temperature. 3 / h, otherwise reduce 12m 3 / h.

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

[0048] Example 3:

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

[0050] 1) Priority should be given to ensuring that the third heating section and soaking section are in the furnace for more than 178 minutes, and the soaking temperature is 1185-1220°C. The temperature difference between the upper and lower surfaces of the slab 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 slab in the heating furnace should be adjusted, with a target value of 32°C, to prevent warping.

[0051] 2) Ensure a reasonable rolling cycle of the rolls. The rolling cycle of 32mm rolls is more than 500t. In order to make full use of the rolls, 32mm rolls can be arranged first, and then 21-31mm rolls. A maximum of 160 rolls can be arranged in each roll cycle. When switching specifications, transition plates are used in the middle 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 basic conditions for precise control of plate shape. The 30mm specification finishing mill corresponds to 14 passes. If the intermediate slab of the roughing mill is warped, the image separation method is used to add a flattening pass to ensure safe biting of the finishing mill.

[0053] 4) The final pass of the finishing mill is controlled according to a slight center wave, and the thickness of the center area of ​​the steel plate should be 0.08 to 0.12 mm thinner than the edge.

[0054] 5) Determine the original width setting shielding value of various specifications. The width setting shielding value of 30mm thickness specification is 4350~4610mm, and the adjustment is made in units of 31mm. The CVC roller stringing value of the finishing mill is controlled by the rolling force deviation of 200t and the roller stringing is adjusted by 14mm. According to the change of laminar water temperature, the water supply volume is increased by 13m for every 2℃ increase in water temperature. 3 / h, otherwise reduce 13m 3 / h.

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

[0056] Example 4:

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

[0058] 1) Priority should be given to ensuring that the third heating section and soaking section are in the furnace for more than 178 minutes, and the soaking temperature is 1185-1220°C. The temperature difference between the upper and lower surfaces of the slab 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 slab in the heating furnace should be adjusted, with a target value of 35°C to prevent warping.

[0059] 2) Ensure a reasonable rolling cycle of the rolls. The rolling cycle of 32mm rolls is more than 500t. In order to make full use of the rolls, 32mm rolls can be arranged first, and then 21-27mm rolls. A maximum of 160 rolls can be arranged in each roll cycle. When switching specifications, transition plates are used in the middle 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 basic conditions for precise control of plate shape. The 32mm specification finishing mill corresponds to 14 passes. If the intermediate slab of the roughing mill is warped, the image separation method is used to add a flattening pass to ensure safe biting of the finishing mill.

[0061] 4) The final pass of the finishing mill is controlled according to a slight center wave, and the thickness of the center area of ​​the steel plate should be 0.08 to 0.12 mm thinner than the edge.

[0062] 5) Determine the original width setting shielding value of various specifications. The shielding value of 32mm thickness specification width setting is 4350~4650mm, and the adjustment is made in 31mm units. The CVC roller stringing value of the finishing mill is controlled by the rolling force deviation of 200t and the roller stringing is adjusted by 15mm. According to the laminar water temperature change, the water supply volume is increased by 15m for every 2℃ increase in water temperature. 3 / h, otherwise reduce 15m 3 / h.

[0063] 6) The method of the present invention increases the qualified rate of the shape of the steel plate 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 4200 mm, characterized in that: The method specifically includes the following contents: 1) When rolling pipeline steel plates with a thickness of 21-27 mm, the third heating section and soaking section should last for more than 120 minutes. When the thickness is greater than 27 mm and not greater than 32 mm, the third heating section and soaking section should last for more than 160 minutes, and the soaking section temperature should be 1185-1230°C. When the billet arrives at the soaking section, the temperature difference between the upper and lower surfaces of the heating furnace should be adjusted, with a target temperature difference of 25-35°C. 2) The rolling cycle of pipeline steel plates with thickness of 21-27 mm is 1500-3000 t, and the rolling cycle of pipeline steel plates with thickness greater than 27 mm and not greater than 32 mm is more than 500 t; 3) The finishing mill passes corresponding to pipeline steel plates with thickness specifications of 21 to 32 mm are 10 to 14 passes; 4) The thickness of the central area of ​​the steel plate is 0.03 to 0.12 mm thinner than that of the edge; 5) Determine the masking values ​​for the original width settings of various specifications. The masking values ​​for the width settings of pipeline steel plates with a thickness of 21 to 27 mm are 4110 to 4550 mm, and the masking values ​​for the width settings of specifications with a thickness greater than 27 mm and not greater than 32 mm are 4345 to 4630 mm.

2. The method for controlling the shape of pipeline steel with a width greater than 4200 mm according to claim 1, characterized in that: In the rolling cycle, each rolling cycle produces a maximum of 160 pieces, first producing pipeline steel plates with a thickness greater than 27 mm and not greater than 32 mm, and then producing pipeline steel plates with a thickness specification of 21 to 27 mm.

3. The method for controlling the shape of pipeline steel with a width greater than 4200 mm according to claim 1, characterized in that: In the process of determining the original width setting shielding values ​​of various specifications, the width setting shielding value is adjusted with 20 to 50 mm as an adjustment unit.

4. The method for controlling the shape of pipeline steel with a width greater than 4200 mm according to claim 1, characterized in that: It also includes determining the CVC roll string values ​​of various specifications of finishing mills. During the determination process, the CVC roll string value of the finishing mill is controlled based on the rolling force deviation of 150 to 200 tons and the adjustment of the roll string by 8 to 19 mm.

5. The method for controlling the shape of pipeline steel with a width greater than 4200 mm according to claim 1, characterized in that: In the process of determining the original width of various specifications and setting the shielding value, according to the change of laminar water temperature, the water supply volume is increased by 10 to 15 m for every 2 to 3 ° C increase in water temperature. 3 / h, otherwise reduce by 10-15m 3 / h.