Method for preventing strip steel from over wide slitting

Abstract

This invention provides a method for preventing strip jamming due to excessive strip width. The method employs a two-stage setting process for the coiler side guide plate opening. The first setting occurs when the strip bites into the finishing mill F1 stand, based on the measured width at the roughing mill exit or the target strip width. This ensures sufficient time for the coiler side guide plate to reach the set position, even when there are significant variations in the target strip width. The second setting occurs when the strip reaches the width measuring device, again setting the coiler side guide plate width based on the actual strip width to prevent jamming accidents caused by excessive strip head width. This invention avoids coiler side guide plate jamming accidents caused by excessive strip head width and the resulting downtime losses. Furthermore, this invention does not require large-scale equipment modifications, significantly improving production efficiency and reducing the occurrence of jamming accidents while reducing spare parts costs.

Description

Technical Field

[0001] This invention relates to the field of iron and steel metallurgical production, and more particularly to a method for preventing scrap accidents caused by strip head being too wide and unable to pass smoothly through the side guide plate of the coiler in the hot rolling process of iron and steel. Background Technology

[0002] Currently, all steel metallurgical manufacturers have hot rolling production lines. The process flow of these hot rolling production lines generally includes heating, rough rolling, finish rolling, and coiling, as detailed below:

[0003] 1) First, according to the rolling plan, load the slabs into the walking beam furnace in sequence;

[0004] 2) After the slab is heated to the target temperature specified by the process, the slab is drawn out one by one by the steel drawing machine and placed on the front roller table of the furnace. Then the hot slab is transported to the roughing mill.

[0005] 3) In the roughing mill, the slab first enters the R1 two-high reversible mill for 1 to 3 passes, then enters the R2 four-high reversible mill for 3 to 7 passes, and then passes through the closely arranged R3 and R4 mills for continuous rolling. During the roughing process, the roughing mill rolls the 200 to 250 mm slab into an intermediate slab of 38 to 60 mm, and then sends it to the finishing mill.

[0006] 4) The intermediate billet is continuously rolled into finished strip steel with a thickness of 1.2 to 25.4 mm by the finishing mill. After the strip steel leaves the finishing mill, it is cooled to the specified temperature by laminar flow cooling equipment on the hot output roller table. Finally, the strip steel is sent to the coiler to be coiled into steel coils.

[0007] In the above-described process, the width of hot-rolled strip steel is a crucial quality indicator for the product, primarily controlled by the roughing and finishing mills. The target width W1 and width tolerance range W2 for each strip are specified according to the user's requirements. For strip steel with acceptable width, the minimum cold-rolled width W of the finished strip is... min The maximum cold-formed width W of the finished strip cannot be less than W1. max It cannot be greater than W1+W2, and the width tolerance range W2 is usually 0 to 20 mm.

[0008] In actual production, some strip steel heads are severely over-width, meaning the maximum cold-state width W of the finished strip steel is excessive. max >W1+W2. To ensure the strip head passes smoothly through the side guide plate, the side guide plate opening setting value W3 must be slightly larger than the maximum cold-state width W of the finished strip. MAX Based on years of production experience, the side guide plate opening setting value W3 and the maximum cold-state width W of the finished strip steel are related. MAXThe difference W4 must be controlled between 80 and 170 mm. If it is less than 80 mm, it is easy to occur the accident of the side guide plate jamming the steel. If it is greater than 170 mm, it is easy to appear the quality defect of tower shape.

[0009] For example:

[0010] The target width W1 = 1000 mm;

[0011] The width tolerance range W2 = 20 mm;

[0012] The maximum cold state theoretical width Wmax of the finished strip steel < W1 + W2, that is, less than 1020 mm, while the maximum cold state width Wmax of the actually produced finished strip steel = 1050 mm, that is, W max > W1 + W2;

[0013] The additional value B1 of the side guide plate = 110 mm;

[0014] The set value W3 of the side guide plate opening = W1 + B1 = 1000 mm + 110 mm = 1110 mm;

[0015] The difference W4 between the set value W3 of the side guide plate opening and the maximum cold state width Wmax of the actually produced finished strip steel = 1110 mm - 1050 mm = 60 mm, that is, W4 < 80 mm. In this case, it is very difficult for the head of the strip steel to pass through the side guide plate smoothly, and it is easy to occur the accident of the side guide plate jamming the steel.

[0016] The above-mentioned accident of jamming the steel has been recorded and occurred many times in actual production, as follows:

[0017] 1. In the coiling unit of the latest Zhanjiang 2250 hot rolling production line, the set value W3 of the side guide plate opening is based on the measured width at the exit of rough rolling. When rolling the strip steel No. 217813901600, the head of the strip steel could not pass through the side guide plate smoothly and the accident of jamming the steel occurred. After investigation, this accident was caused by the serious over-width of the head of the strip steel.

[0018] 2. In the coiling unit of the 1880 hot rolling production line of a certain iron and steel company, the set value W3 of the side guide plate opening is based on the target width W1. When rolling the strip steel No. 008215470300, the head of the strip steel could not pass through the side guide plate smoothly and the accident of jamming the steel occurred, which was also caused by the serious over-width of the head of the strip steel.

[0019] The main reason is the limitation of the hot rolling process itself, which makes it very difficult to completely solve the serious over-width phenomenon of the head of the strip steel, and the accident of the side guide plate jamming the steel caused by this cannot be eliminated. The detailed reasons are as follows:

[0020] Existing technology uses a method to calculate the side guide plate opening setting value W3 based on the target width W1 or the actual measured width at the roughing mill exit. This method is based on the previous understanding of width control, which held that as long as the roughing mill controlled the strip width tolerance within the tolerance range W2, the finishing mill process generally would not cause serious overwidth issues. Therefore, calculating the side guide plate opening setting value W3 based on the target width W1 or the actual measured width at the roughing mill exit could basically meet the requirement of preventing side guide plate jamming accidents. However, with the widespread application of width-fixing mills in hot rolling production lines, the continuous increase in pressure measurement, and the continuous expansion of new steel grades, the width of finishing mill units tends to increase. This means that sometimes the roughing mill can control the strip width tolerance within the tolerance range W2, but the finishing mill process can still result in serious overwidth issues. Furthermore, the coiling side guide plate opening setting value W3 needs to be issued immediately after the finishing mill F1 bites the strip. If it is issued later, when there are significant changes in the target strip width specifications before and after, the coiling side guide plate may not have enough time to reach the set position, thus causing a jamming accident.

[0021] Therefore, there is an urgent need for a new method to effectively prevent strip from getting stuck due to its excessive width, so that the strip head can pass smoothly through the side guide plate of the coiler and reduce scrap steel. Summary of the Invention

[0022] To address the aforementioned problems, this invention provides a method for preventing strip jamming caused by excessively wide strip heads that cannot pass smoothly through the coiler side guide plate. This invention sets a value for the coiler side guide plate based on the actual measured strip width at the roughing mill exit, the target strip width, or a predetermined value when the strip bites into the finishing mill F1 stand. When the strip reaches the width measuring device, the set value for the coiler side guide plate is corrected based on the actual strip width, thereby reducing jamming accidents and the resulting downtime losses.

[0023] The present invention provides a method for preventing excessively wide strip steel from jamming, comprising a rolling mill and a coiler side guide plate, the specific steps of which are as follows:

[0024] 1) The opening of the side guide plate of the winding machine is set using a two-stage method, with a first setting and a second setting.

[0025] 2) In step 1), the initial setup method is as follows:

[0026] After the F1 stand of the finishing mill bites the steel, the first coiling side guide plate opening setting value W3 is issued. In this step, when the target width specifications of the front and rear strips change significantly, the coiling side guide plate has sufficient time to move to the set position. The formula is as follows:

[0027] W3 = W1 + B1;

[0028] In the formula:

[0029] W3 is the setting value for the opening of the side guide plate during the first winding, in mm;

[0030] W1 is the target width, in mm;

[0031] B1 is the additional value for the side guide plate, in mm;

[0032] 3) In step 1), the second setting method is as follows:

[0033] After the strip head exits the finishing mill, the maximum cold-state width W of the finished strip is measured using a finishing mill width gauge or a coil width gauge. max Based on this, the second winding side guide plate opening setting value W5 is issued. This step prevents steel jamming accidents caused by excessive head width in the side guide plate. The formula is as follows:

[0034] W5 = W1 + B1 + B2;

[0035] In the formula:

[0036] W5 is the setting value for the opening of the second winding side guide plate, in mm;

[0037] W1 is the target width, in mm;

[0038] B1 is the additional value for the side guide plate, in mm;

[0039] B2 is the adjusted value for the actual measured width of the strip, in mm;

[0040] When using the cold-state value of the actual measured width of the strip, the deviation between the target width and the maximum cold-state width Wmax of the finished strip is △W, in mm. The adjustment value B2 of the actual measured width of the strip is obtained through △W. Then, the setting value W5 of the second winding side guide plate opening is calculated according to the above formula. The difference between W5 and the maximum cold-state width Wmax of the finished strip is W4 = W5 - Wmax. If W4 > 80 mm, the strip head can pass through the side guide plate smoothly without the side guide plate jamming accident. If W4 < 80 mm, the side guide plate jamming accident will occur.

[0041] For the relationship between △W and the adjustment value B2 of the actual measured width of the strip, please refer to Table 1:

[0042]

[0043] Table 1: Relationship between △W and the adjustment value B2 of the actual measured width of the strip

[0044] Note: In Table 1 above, B2 is a range value, and the actual product of the strip needs to be considered to obtain an accurate value of B2.

[0045] 4) In step 3), when △W < 30, the excessive width will not cause the side guide plate to jam the steel, and there is no need to set it a second time. However, when △W ≥ 80, the measured value is considered unreliable, and no second setting is required.

[0046] 5) In step 3), B2 returns to zero after the coiling pinch roll bites the steel.

[0047] According to a method for preventing strip from becoming too wide and jammed, in the second setting method of step 3), the width measuring instrument between the finishing mill and coiling detects the actual width of the strip as a hot-state value, and calculates the cold-state value from this hot-state value using the following specific formula:

[0048] Cold state value = Hot state value / K;

[0049] In the formula:

[0050] The value of K ranges from 100% to 102%;

[0051] Then calculate the deviation △W between the target width and the maximum cold width Wmax of the finished strip, in mm. According to the formula: W5=W1+B1+B2, calculate the second winding side guide plate opening setting value W5. That is, the second setting method in step 3) can use either the cold value or the hot value.

[0052] According to a method for preventing strip from jamming due to excessive width, the specific control of the rolling mill in the first setting method of step 2) is as follows:

[0053] When the strip head bites into the F1 stand of the finishing mill, the pressure measuring head of the F1 stand detects the rolling force and transmits the rolling force signal to the finishing mill base automation computer. The finishing mill base automation computer determines that the F1 stand has bitten the strip based on the rolling force and transmits the F1 biting signal to the process machine. After receiving the finishing mill F1 biting signal, the process machine sends the target width W1 of the strip to the coiling base automation computer. The coiling base automation computer calculates the opening set value W3 based on the target width W1 according to the formula: W3 = W1 + B1, and controls the hydraulic servo system and hydraulic cylinder to push the side guide plate to the opening set value W3.

[0054] According to a method for preventing strip from jamming due to excessive width, the specific control of the rolling mill in step 3) of the second setting method is as follows:

[0055] After the strip exits the finishing mill, the finishing mill width gauge or coiling width gauge measures the actual width of the strip. The main unit of the width gauge calculates the cold-state width of the finished strip and transmits the data to the coiling base automation computer. The coiling base automation computer then calculates the maximum cold-state width W of the finished strip. maxBased on this, the second winding side guide plate opening setting value W5 is issued, with the formula: W5=W1+B1+B2, to prevent the side guide plate from jamming due to excessive head width. In this step, when △W<30, the excessive width will not cause the side guide plate to jam, and the second setting is not required. However, when △W≥80, the measured value is considered unreliable, and the second setting is not performed.

[0056] The present invention provides a method for preventing steel strip from jamming due to its excessive width. The overall concept is as follows:

[0057] When the strip enters the finishing mill F1 stand, the coiling side guide plate is set with a preset value based on the actual measured width at the roughing mill exit or the target width of the strip. This ensures that the coiling side guide plate has sufficient time to reach the set position when there are significant changes in the target width specifications of the strip before and after. When the strip reaches the width measuring device, the setting value of the coiling side guide plate is set again based on the actual width of the strip to prevent strip jamming accidents caused by the strip head being too wide.

[0058] The method for preventing excessively wide steel strip from jamming using the present invention achieves the following beneficial effects:

[0059] 1. The method of the present invention for preventing strip from jamming due to excessive width can avoid accidents caused by excessive width of the strip head on the winding side guide plate and the resulting downtime losses;

[0060] 2. The method of the present invention for preventing steel strip from jamming due to excessive width does not require large-scale modification of equipment. While reducing spare parts costs, it greatly improves production efficiency and reduces the occurrence of steel jamming accidents. Attached Figure Description

[0061] Figure 1 This is a schematic diagram of the strip width for a method to prevent strip from jamming due to excessive width according to the present invention;

[0062] Figure 2 This is a schematic diagram of an over-wide strip at the head, as described in the present invention, for a method to prevent over-wide strip from jamming.

[0063] Figure 3 This is a diagram showing the relationship between the opening of the side guide plate and the target width of the strip in a method for preventing strip from jamming due to excessive width according to the present invention.

[0064] Figure 4 This is a logic diagram illustrating an implementation of a method for preventing excessively wide strip steel from jamming, according to the present invention. Detailed Implementation

[0065] The following description, in conjunction with the accompanying drawings and embodiments, further describes the technical means, creative features, objectives, and effects of the method for preventing excessively wide strip steel from jamming according to the present invention.

[0066] like Figures 1-4As shown, a method for preventing excessively wide strip steel from jamming includes a rolling mill and a coiler side guide plate, the specific steps of which are as follows:

[0067] 1) The opening of the side guide plate of the winding machine is set using a two-stage method, with a first setting and a second setting.

[0068] 2) In step 1), the initial setup method is as follows:

[0069] After the F1 stand of the finishing mill bites the steel, the first coiling side guide plate opening setting value W3 is issued. In this step, when the target width specifications of the front and rear strips change significantly, the coiling side guide plate has sufficient time to move to the set position. The formula is as follows:

[0070] W3 = W1 + B1;

[0071] In the formula:

[0072] W3 is the setting value for the opening of the side guide plate during the first winding, in mm;

[0073] W1 is the target width, in mm;

[0074] B1 is the additional value for the side guide plate, in mm;

[0075] 3) In step 1), the second setting method is as follows:

[0076] After the strip head exits the finishing mill, the maximum cold-state width W of the finished strip is measured using a finishing mill width gauge or a coil width gauge. max Based on this, the second winding side guide plate opening setting value W5 is issued. This step prevents steel jamming accidents caused by excessive head width in the side guide plate. The formula is as follows:

[0077] W5 = W1 + B1 + B2;

[0078] In the formula:

[0079] W5 is the setting value for the opening of the second winding side guide plate, in mm;

[0080] W1 is the target width, in mm;

[0081] B1 is the additional value for the side guide plate, in mm;

[0082] B2 is the adjusted value for the actual measured width of the strip, in mm;

[0083] When using the cold-state value of the actual measured width of the strip, the deviation between the target width and the maximum cold-state width Wmax of the finished strip is △W, in mm. The opening setting value W5 of the second winding side guide plate is calculated based on the above formula.

[0084] 4) In step 3), when △W<30, the excessive width will not cause the side guide plate to jam the steel, and no second setting is required. However, when △W≥80, the measured value is considered unreliable, and no second setting is required.

[0085] 5) In step 3), B2 returns to zero after the coiling pinch roll bites the steel.

[0086] In the second setting method of step 3), the width measuring instrument between the finishing mill and the coiling unit detects the actual width of the strip as the hot state value. The cold state value is then calculated from this hot state value using the following formula:

[0087] Cold state value = Hot state value / K;

[0088] In the formula:

[0089] The value of K ranges from 100% to 102%;

[0090] Then calculate the deviation △W between the target width and the maximum cold width Wmax of the finished strip, in mm. According to the formula: W5=W1+B1+B2, calculate the second winding side guide plate opening setting value W5. That is, the second setting method in step 3) can use either the cold value or the hot value.

[0091] In the initial setup method of step 2), the specific control of the rolling mill is as follows:

[0092] When the strip head bites into the F1 stand of the finishing mill, the pressure measuring head of the F1 stand detects the rolling force and transmits the rolling force signal to the finishing mill base automation computer. The finishing mill base automation computer determines that the F1 stand has bitten the strip based on the rolling force and transmits the F1 biting signal to the process machine. After receiving the finishing mill F1 biting signal, the process machine sends the target width W1 of the strip to the coiling base automation computer. The coiling base automation computer calculates the opening set value W3 based on the target width W1 according to the formula: W3 = W1 + B1, and controls the hydraulic servo system and hydraulic cylinder to push the side guide plate to the opening set value W3.

[0093] In the second setting method of step 3), the specific control of the rolling mill is as follows:

[0094] After the strip exits the finishing mill, the finishing mill width gauge or coiling width gauge measures the actual width of the strip. The main unit of the width gauge calculates the cold-state width of the finished strip and transmits the data to the coiling base automation computer. The coiling base automation computer then calculates the maximum cold-state width W of the finished strip. maxBased on this, the second winding side guide plate opening setting value W5 is issued, with the formula: W5=W1+B1+B2, to prevent the side guide plate from jamming due to excessive head width. In this step, when △W<30, the excessive width will not cause the side guide plate to jam, and the second setting is not required. However, when △W≥80, the measured value is considered unreliable, and the second setting is not performed.

[0095] Example - A method for preventing excessively wide strip steel from jamming, according to the present invention, was implemented on the 2050 production line of a hot rolling mill of a steel company. The specific effects are as follows:

[0096] Target width W1 = 1000mm;

[0097] Width tolerance range W2 = 20mm;

[0098] Additional value of side guide plate B1 = 110mm;

[0099] First setting: After the F1 stand of the finishing mill bites the steel, calculate and issue the first setting value of the coiling side guide plate opening W3 = 1000mm + 110mm = 1110mm according to W3 = W1 + B1;

[0100] Second setting: After the strip head exits the finishing mill, the width measuring instrument between the finishing mill and coiling detects the actual width of the strip. Based on this, the second coiling side guide plate opening setting value W5 is issued. In this embodiment, the cold-state value of the actual measured width of the strip is used. The deviation between the target width and the maximum cold-state width Wmax of the finished strip is ΔW = 50mm. The relationship between ΔW and the adjustment value B2 of the actual measured width of the strip can be referred to the example table of the relationship between ΔW and the adjustment value B2 of the actual measured width of the strip in Table 2 below to obtain the accurate value of B2:

[0101]

[0102]

[0103] Table 2: Example Table of Relationship between △W and Adjustment Value B2 of Measured Strip Width

[0104] Based on Table 2 above and the formula: W5=W1+B1+B2, the second winding side guide plate opening setting value W5=1000mm+110mm+30mm=1140mm is calculated.

[0105] The difference between the second winding side guide plate opening setting value W5 and the maximum cold width Wmax of the finished strip is W4 = 1140mm - 1050mm = 90mm, indicating that W4 > 80mm. Under these conditions, the strip head can pass smoothly through the side guide plate without the side guide plate jamming accident occurring.

[0106] When the coiling pinch roll bites the steel, B2 returns to zero.

[0107] The present invention provides a method for preventing strip jamming caused by excessively wide strip heads, which can avoid accidents caused by strip jamming on the winding side guide plate and the resulting downtime losses. The present invention does not require large-scale equipment modifications, and while reducing spare parts costs, it greatly improves production efficiency and reduces the occurrence of strip jamming accidents.

[0108] However, those skilled in the art should recognize that the above embodiments are only used to illustrate this application and are not intended to limit this application. Any changes or modifications to the above embodiments within the spirit and essence of this application will fall within the scope of the claims of this application.

Claims

1. A method for preventing strip steel from jamming due to excessive width, comprising a rolling mill and a coiler side guide plate, the specific steps of which are as follows: 1) The opening of the side guide plate of the winding machine is set using a two-stage method, with a first setting and a second setting. 2) In step 1), the initial setup method is as follows: After the F1 stand of the finishing mill bites the steel, the first coiling side guide plate opening setting value W3 is issued. In this step, when the target width specifications of the front and rear strips change significantly, the coiling side guide plate has sufficient time to move to the set position. The formula is as follows: W3 = W1 + B1; In the formula: W3 is the setting value for the opening of the side guide plate during the first winding, in mm; W1 is the target width, in mm; B1 is the additional value for the side guide plate, in mm; 3) In step 1), the second setting method is as follows: When the strip head comes out of the finishing mill train, the cold maximum width W of the finished strip is detected by the finishing gauge or the coiling gauge max Accordingly, the second coiling side guide opening setting value W5 is given, and this step prevents the side guide from being stuck by the head width, and the formula is as follows: W5 = W1 + B1 + B2; In the formula: W5 is the setting value for the opening of the second winding side guide plate, in mm; W1 is the target width, in mm; B1 is the additional value for the side guide plate, in mm; B2 is the adjusted value for the actual measured width of the strip, in mm; When using the cold-state value of the actual measured width of the strip, the deviation between the target width and the maximum cold-state width Wmax of the finished strip is △W, in mm. The adjustment value B2 of the actual measured width of the strip is obtained through △W. Then, the setting value W5 of the second winding side guide plate opening is calculated according to the above formula. The difference between W5 and the maximum cold-state width Wmax of the finished strip is W4 = W5 - Wmax. If W4 > 80 mm, the strip head can pass through the side guide plate smoothly without the side guide plate jamming accident. If W4 < 80 mm, the side guide plate jamming accident will occur. 4) In step 3), when △W < 30, the excessive width will not cause the side guide plate to jam the steel, and there is no need to set it a second time. However, when △W ≥ 80, the measured value is considered unreliable, and no second setting is required. 5) In step 3), B2 returns to zero after the coiling pinch roll bites the steel.

2. The method for preventing strip steel from jamming due to excessive width as described in claim 1, characterized in that, In the second setting method of step 3), the width measuring instrument between the finishing mill and the coiling unit detects the actual width of the strip as the hot state value, and calculates the cold state value from this hot state value using the following formula: Cold state value = Hot state value / K; In the formula: The value of K ranges from 100% to 102%; Then calculate the deviation △W between the target width and the maximum cold-state width Wmax of the finished strip, in mm. According to the formula: W5=W1+B1+B2, calculate the second winding side guide plate opening setting value W5. That is, the second setting method in step 3) can use either the cold state value or the hot state value.

3. The method for preventing strip steel from jamming due to excessive width as described in claim 1, characterized in that, In the first setting method of step 2), the specific control of the rolling mill is as follows: When the strip head bites into the F1 stand of the finishing mill, the pressure measuring head of the F1 stand detects the rolling force and transmits the rolling force signal to the finishing mill base automation computer. The finishing mill base automation computer determines that the F1 stand has bitten the strip based on the rolling force and transmits the F1 biting signal to the process machine. After receiving the finishing mill F1 biting signal, the process machine sends the target width W1 of the strip to the coiling base automation computer. The coiling base automation computer calculates the opening set value W3 based on the target width W1 according to the formula: W3 = W1 + B1, and controls the hydraulic servo system and hydraulic cylinder to push the side guide plate to the opening set value W3.

4. The method for preventing strip steel from jamming due to excessive width as described in claim 1, characterized in that, In the second setting method of steps 3) and 4), the specific control of the rolling mill is as follows: When the strip head comes out of the finishing mill, the actual width of the strip is measured by the finishing gauge or the coiling gauge. The data is transmitted to the coiling basic automation computer, which calculates the cold width of the finished strip according to the maximum cold width W max of the finished strip, and issues the second setting value W5 of the coiling side guide opening according to the formula: W5 = W1 + B1 + B2, to prevent the side guide from being jammed by the over-wide head. In this step, when AW < 30, the over-wide head will not cause the side guide to be jammed, so the second setting is not needed. When AW ≥ 80, the measured value is considered to be unreliable, and the second setting is not performed.

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