Control method for improving strip head mark of cold-rolled strip steel coiling machine

Abstract

The invention discloses a control method for improving a strip head mark of a cold-rolled strip steel coiling machine, which is used for eliminating the strip head mark by using a high-elasticity sleeve and setting the tension of taper tension, large tension and small tension coiling stages, and specifically comprises the following steps: a coiling assisting preparation stage: when the tension is preset to be T0 and the thickness of strip steel is greater than or equal to 0.8 mm, starting a taper tension mode; in the taper tension coiling stage, tension is established when the strip steel is wound to the S1 circle, and the tension T1 is 1.5-3.0 times of T0, S1lt; 1 circle; in the large-tension coiling stage, when the winding is performed to S2 circles, the tension T2 is switched to be 0.1-0.9 times of T0 and S2lt; 5 circles; in the small-tension coiling stage, T0 is switched when winding is conducted to S3 circles, and S3 is larger than or equal to 5 circles; a constant tension coiling stage: coiling at T0 to the end; wherein T0 = t * H * B, H is the thickness, B is the width, and t is the unit tension. Through tension gradient adjustment and the high-elasticity sleeve, the belt head printing area is effectively shortened, and the degree of the belt head printing area is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of coiling process control of cold-rolled products, in particular to a control method for improving the head mark of a cold-rolled strip coiler. Background Art

[0002] The head mark defect is a common problem in the cold rolling coiling process. When the cold rolled steel coil is coiled into a coil, the first turn of the strip will form a bulge on the sleeve of the coiler. The bulge area here acts as a curvature mutation area. When the subsequent strip passes through this area, the strip in the bulge area will produce a certain degree of plastic deformation under the combined action of the coiling tension and the sleeve winding force. This deformation causes a horizontal mark to appear in each turn of the strip, which runs through the width of the strip. This horizontal mark is usually called the "head mark" in the industry. The severity of the head mark will gradually become flat as the coil diameter increases and eventually disappear. The thicker the strip, the more serious the head mark, and the longer the plastic deformation area, which will have an adverse effect on the subsequent deep processing, spraying, baking paint and other processes of the steel coil. Long-term production practice experience shows that the head mark problem is particularly prominent when the strip thickness reaches or exceeds the specification of 0.8mm. Therefore, how to effectively shorten the length of the area where the head mark is produced and reduce the degree of the head mark has become a control difficulty that needs to be solved urgently in the winding process. Summary of the invention

[0003] The purpose of the present invention is to provide a control method for improving the head mark of a cold-rolled strip coiler. This method can solve the problem that the length of the head mark producing area of ​​the existing strip with a thickness of more than 0.8 mm is long and the degree of the head mark is serious.

[0004] In order to solve the above problems, the technical solution adopted by the present invention is: this control method for improving the head mark of the cold-rolled strip coiler uses a high elastic sleeve outside the coiler mandrel, sets the tension of the taper tension coiling stage and adjusts the tension of the large tension coiling stage and the small tension coiling stage, and embeds the head of the strip into the sleeve to eliminate the head mark. The specific steps are as follows: Step (1), coiling preparation stage: preset the coiling tension T0 and judge the online strip thickness. When the strip thickness is less than 0.8 mm, adopt the constant tension coiling mode; when the strip thickness is ≥ 0.8 mm, intervene in the taper tension control mode for coiling; Step (2), taper tension winding stage: when the strip is wound around the sleeve to a preset number of turns S1, the strip is tensioned, and the tension is set to T1, S1 turns < 1 turn; Step (3), high tension winding stage: when the strip is wound around the sleeve to a preset number of turns S2, the auxiliary winding stage is completed, and the tension setting is adjusted from T1 to T2, S2 turns < 5 turns; Step (4), when the tension is switched to T2 and the strip is wound around the sleeve to a preset number of turns S3, the tension setting is adjusted from T2 to T0, S3 turns ≥ 5 turns; Step (5), after the tension reaches the set value T0, the coiling is performed at a constant tension T0 until the coiling of the strip steel is completed; In the above steps, T0=t×H×B, where H is the strip thickness in mm; B is the strip width in mm; t is the unit tension of the strip steel grade series in daN / mm²; The tension is T1>T0>T2, T1 is 1.5 to 3.0 times of T0, and T2 is 0.1 to 0.9 times of T0.

[0005] In the above-mentioned technical solution of the control method for improving the head mark of the cold-rolled strip coiler, a more specific technical solution can also be: the coiler maintains a constant threading speed v during steps (1) to (4); after entering step (5), the unit speeds up.

[0006] In some possible implementation schemes, the belt threading speed v is in the range of 30 to 70 m / min.

[0007] In some possible implementation schemes, the sleeve is a rubber sleeve.

[0008] In some possible implementation schemes, a plurality of spiral grooves are distributed on the outer surface of the sleeve.

[0009] In some possible implementation schemes, a plurality of straight grooves are provided on the inner surface of the sleeve.

[0010] In some possible implementation schemes, the groove bodies of the spiral groove and the straight groove are both arc structures.

[0011] Due to the adoption of the above technical solution, the present invention has the following beneficial effects compared with the prior art: 1. The elastic properties of the high-elastic sleeve adopted in the present invention enable it to better fit the strip head part, ensuring that the strip head can be tightly embedded in the sleeve at the initial stage of coiling, reducing the formation of strip head marks; in addition, the high-elastic sleeve can effectively absorb and disperse the impact force of the strip on the sleeve during the coiling process, reduce the stress concentration in the strip head area, and thus reduce the generation of strip head marks; in the tapered tension coiling stage, by setting a higher tension build-up tension T1 (1.5 to 3.0 times of T0), it is ensured that the strip head can be tightly embedded in the sleeve at the initial stage of coiling, reducing the generation area of ​​the strip head mark; as the number of strip winding turns increases, the tension is gradually reduced to avoid excessive tension causing the strip to produce Plastic deformation reduces the degree of strip head marks; in the high-tension winding stage, when the strip is wound around the sleeve to a preset number of turns S2, the tension is switched from T1 to T2 to reduce the tension, ensuring that the strip is evenly stressed during the winding process and reducing the occurrence of strip head marks; in the low-tension winding stage, when the strip is wound around the sleeve to a preset number of turns S3, the tension is switched from T2 to T0, and the strip is wound to the end with a constant tension of T0. This stable tension setting helps to maintain the flatness of the strip and further reduce the occurrence of strip head marks. The method is easy to operate, suitable for actual production environments, can significantly improve production efficiency, and reduce downtime and scrap rate caused by strip head marks.

[0012] 2. In steps (1) to (4), maintaining a constant threading speed v can ensure that the strip is evenly stressed at the initial stage of coiling, especially at the critical stage when the strip head is embedded in the sleeve, avoiding tension instability caused by speed fluctuations; a stable threading speed helps the strip to fit tightly with the high-elastic sleeve, reducing stress concentration in the strip head area, thereby effectively reducing the generation of strip head marks; in step (5), when the strip head mark problem has been basically solved and the strip coiling enters a stable stage, increasing the unit speed can improve production efficiency without having a negative impact on the control of the strip head mark.

[0013] 3. Controlling the tape threading speed within the range of 30 to 70 m / min can not only ensure the stability of the coiling process, but also meet the requirements of production efficiency. In this tape threading speed range, a lower tape threading speed is suitable for the critical stage of embedding the strip head into the sleeve to ensure that the strip and the sleeve fit closely. A higher tape threading speed is suitable for the subsequent stable coiling stage to improve production efficiency.

[0014] 4. The rubber sleeve has excellent high elasticity and buffering performance, which can effectively absorb the impact force and vibration generated during the strip coiling process, reduce the stress concentration in the strip head area, and thus reduce the formation of strip head marks; the softness of the rubber material enables it to better fit the strip head part, ensuring that the strip head is tightly embedded in the sleeve at the initial stage of coiling, reducing the formation of strip head marks.

[0015] 5. The design of the spiral groove on the outer surface of the sleeve can evenly distribute the tension of the strip during the coiling process, avoid local stress concentration, and thus reduce the generation of head marks; the design of the straight groove on the inner surface of the sleeve can enhance the connection stability between the sleeve and the coiler mandrel, prevent the sleeve from deflecting or loosening during the coiling process, and ensure the stability of the coiling process.

[0016] 6. The arc structure of the spiral groove and straight groove can effectively reduce the stress concentration of the strip and sleeve during the coiling process, and avoid strip damage or sleeve wear caused by sharp edges. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the winding tension and the number of winding turns of this method.

[0018] Figure 2 It is a schematic diagram of the coiling equipment used in this method.

[0019] Figure 3 It is a schematic diagram of the structure of the sleeve.

[0020] Figure 4 yes Figure 3 Side schematic diagram of .

[0021] Explanation of the accompanying drawings: 1. pressure roller; 2. steering roller; 3. strip steel; 4. winding-aiding belt; 5. sleeve; 5-1. spiral groove; 5-2. straight groove; 6. coiling machine core shaft. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the accompanying drawings: like Figure 2 As shown in the figure, the coiling equipment used in the control method for improving the head mark of the cold-rolled steel strip coiler includes a pressure roller 1, a steering roller 2, a coiling belt 4, a sleeve 5, a coiling machine mandrel 6, and a clamping device. The coiling machine mandrel 6 is located at the center of the coiler and is used to support and drive the coiling of the steel strip 3. The sleeve 5 is a highly elastic sleeve 5 tightly mounted on the coiling machine mandrel 6. The sleeve 5 in this embodiment is a rubber sleeve, such as Figure 3 and Figure 4As shown, in order to make the sleeve 5 have higher elasticity, the outer surface of the sleeve 5 is distributed with several spiral grooves 5-1, which can also increase the friction with the strip steel 3 and help the strip head to better embed into the sleeve 5. Furthermore, the inner surface of the sleeve 5 is provided with multiple straight grooves 5-2 to optimize the elasticity and deformation capacity of the sleeve 5. The groove bodies of the spiral grooves 5-1 and the straight grooves 5-2 are both arc structures, which can reduce stress concentration. The auxiliary winding belt 4 is close to the outer surface of the sleeve 5, and the tension force output is realized through the tension adjustment valve. The pressure roller 1 and the steering roller 2 are located at the input end of the strip steel 3, which are used to feed the straight strip steel 3 into the coiler and apply a certain pressure so that the strip steel 3 can be tightly wound on the sleeve 5. In the auxiliary winding stage, the auxiliary winding belt 4 is in close contact with the strip steel 3, helping the strip steel 3 to be better wound on the sleeve 5. As the winding process proceeds, the strip steel gradually forms a coil on the sleeve. The clamping device is located at the output end of the coiler and is used to maintain the stability of the steel strip 3 during the coiling process to prevent the steel strip 3 from deflecting or loosening during the coiling process.

[0023] This method for improving the control of the head mark of the cold-rolled strip coiler uses a high elastic sleeve outside the coiler mandrel, sets the tension of the taper tension coiling stage and adjusts the tension of the high tension coiling stage and the low tension coiling stage, so that the head of the strip is embedded in the sleeve to eliminate the head mark. The specific steps are as follows: Step (1), coiling preparation stage: preset coiling tension T0, which is calculated based on the strip thickness H, strip width B and unit tension t of the steel grade series, and the calculation formula is T0=t×H×B, where the strip thickness H is in mm, the strip width B is in mm, and the unit tension t of the strip steel grade series is in daN / mm²; at the same time, judge the thickness of the online strip. When the strip thickness is less than 0.8mm, adopt the constant tension coiling mode; when the strip thickness is ≥0.8mm, intervene in the taper tension control mode for coiling, see Figure 1 ; In this stage, the pressure roller and steering roller involved in the coiling and auxiliary coiling perform the pressing action, and the straight strip steel needs to be wound into a coil through the clamping device of the coiler; the clamping device is closed, the auxiliary coiling belt is close to the sleeve, and the auxiliary coiling belt realizes the tension output through the tension adjustment valve; Step (2), tapered tension winding stage: when the strip steel auxiliary winding sleeve is wound to a preset number of turns S1, the strip tension is built up, S1 turns < 1 turn, and the tension is set to T1, T1> T0, and T1 is 1.5 to 3.0 times T0; during the rapid tension building process of S1 turns, the strip head maintains its own threading inertia and is simultaneously subjected to the combined effects of the large winding tension, the tension of the auxiliary winding belt and the torque of the mandrel, resulting in an instantaneous force mutation, which embeds the strip head into the soft sleeve; Step (3), high tension winding stage: when the strip is wound around the sleeve to a preset number of turns S2, the auxiliary winding stage is completed, S2 turns < 5 turns; at this time, the tension setting is adjusted from T1 to T2, T0> T2, T2 is 0.1 to 0.9 times T0, at the same time, the pressure roller and the steering roller are opened, the clamping device is also opened, and the auxiliary winding belt is unloaded; Step (4), tension switching and adjustment stage: when the tension is switched to T2 and the strip is wound around the sleeve to the preset number of turns S3, the tension setting is adjusted from T2 to T0, S3 turns ≥ 5 turns; by rapidly decreasing the tension value, an artificial relatively loose winding area is created in the area of ​​S2 turns to S3 turns, which is used to quickly relieve the plastic deformation area of ​​the strip head protrusion, and basically control the strip head mark defect within the "hard core" of T1 high tension and the "soft area" of T2 low tension; Step (5), constant tension winding stage: after the tension is adjusted to the set value T0, the coiling is performed at the constant tension T0 until the coiling of the strip steel is completed; In the above steps, during steps (1) to (4), the coiler maintains a constant threading speed v, which is in the range of 30 to 70 m / min. After entering step (5), the unit speeds up to the normal production speed during this stage.

[0024] The tension of the strip during the production process of the continuous hot-dip galvanizing unit is actually the sum of the stress on the cross section. In order to achieve the flatness and stable coil feeding of the strip, the tension should be controlled within a reasonable range. Since the cross section of the produced strip changes frequently, in order to better maintain the tension system, the continuous unit will establish a matrix unit tension base table based on actual experience.

[0025] In Examples 1 to 10, a 0.4-2.5×1880mm continuous hot-dip galvanizing unit coiling production line is used to coil CQ series steels using the method as an example. Table 1 is a unit tension base table for the continuous unit coiling area of ​​the steel.

[0026] Table 1

[0027] Example 1 The CQ series strip with a coiling thickness of 0.4mm and a width of 1800mm has a base unit tension of 31.2daN / mm 2 , then the winding tension T0 = t×H×B = 31.2daN / mm 2 ×0.4mm×1800mm=22464N; the strip thickness is less than 0.8mm, and the constant tension coiling mode is adopted, and the coiler maintains a constant threading speed of 30m / min. Figure 1As shown, this embodiment is a thin strip steel with a thickness of less than 0.8 mm, and the head mark has little effect. The winding method of the dotted line part is adopted, that is, the winding tension is increased at S2 turns (within the range of 1 to 5 turns), and stable winding is started when the tension reaches T0. Figure 1 S4 is the number of winding turns from tension 0 to tension T1, which is between S1 and S2 turns; S5 is the number of winding turns from tension T1 reduced to T2, which is between S2 and S3 turns.

[0028] Examples 2 to 4 are coiling of CQ series strip steel with a coil thickness range of [0.80~1.49] mm. The tension settings and changes during the coiling process of these examples are as follows:

[0029] Examples 5 to 7 are coiling of CQ series strip steel with a coil thickness range of [1.50~1.99] mm. The tension settings and changes during the coiling process of these examples are as follows:

[0030] Examples 8 to 10 are coiling of CQ series strip steel with a coil thickness range of [2.00-2.50] mm. The tension settings and changes during the coiling process of these examples are as follows:

[0031] In the above embodiment, the coiling tension T0 is calculated based on the thickness, width and base unit tension of the strip. S1 represents the number of turns to start building tension. As the thickness of the coiled steel coil increases, the number of turns of S1 to start building tension will gradually decrease, because thicker strip steel can form a stable coiling shape faster at the beginning of coiling, thereby allowing tension to be applied earlier. The large tension T1 in stage 1 is a multiple of T0, which is used to provide sufficient tension at the beginning of coiling to ensure stable coiling of the strip steel; as the thickness of the strip steel increases, the multiple of the large tension T1 relative to the initial tension T0 will decrease, because thicker strip steel has stronger structural stability when coiling, and does not require excessive tension to maintain the embedded state of the strip head. The small tension T2 in stage 2 is another multiple of T0, which is used to appropriately reduce the tension during the coiling process to reduce the deformation and damage of the strip steel; the multiple value of the small tension T2 relative to T0 will increase with the increase of the thickness of the strip steel. If the thicker strip steel needs more time to relieve the plastic deformation zone of the strip head protrusion, then T2 will increase relative to T0. S2 indicates the number of turns in which the tension is lowered. S2 will gradually increase as the thickness of the strip increases, because thicker strips need more time to adapt to the change in tension and remain stable. S3 indicates the number of turns in which the tension is increased to T0. S3 will gradually decrease as the thickness of the strip increases, because thicker strips have stronger structural stability during the coiling process, so the tension can be restored to the initial value T0 at an earlier stage. Finally, the coiling of the strip is completed with a constant tension of T0.

[0032] By uncoiling and grinding with oilstones the CQ series steel grades of Examples 2 to 10, the length of the head mark area of ​​the steel coil with a thickness range of [0.80~1.49] mm is controlled within 15 meters; the length of the head mark area of ​​the steel coil with a thickness range of [1.50~1.99] mm is controlled within 25 meters; the length of the head mark area of ​​the steel coil with a thickness range of [2.00~2.50] mm is controlled within 30 meters. This proves that the coiling method and tension control strategy adopted are effective in improving the coiling quality of the strip and reducing the length of the head mark.

[0033] In Example 11 to Example 19, a 0.4-2.5×1880mm continuous hot-dip galvanizing unit coiling production line is used to coil IF series steels using the present method as an example. Table 2 is a unit tension base table for the continuous unit coiling area of ​​the steels.

[0034] Table 2

[0035] Examples 11 to 13 are coiling of IF series strip steel with a coil thickness range of [0.80~1.49] mm. The tension settings and changes during the coiling process of these examples are as follows:

[0036] Examples 14 to 16 are coiling of IF series strip steel with a coil thickness range of [1.50-1.99] mm. The tension settings and changes during the coiling process of these examples are as follows:

[0037] Examples 17 to 19 are coiling of IF series strip steel with a coil thickness range of [2.00-2.50] mm. The tension settings and changes during the coiling process of these examples are as follows:

[0038] By uncoiling and grinding with oilstones the IF series steel grades of Examples 2 to 10, the length of the head mark of the steel coil with a thickness of [0.80-1.49] is controlled within 20 meters; the length of the head mark of the steel coil with a thickness of [1.50-1.99] is controlled within 35 meters; the length of the head mark of the steel coil with a thickness of [2.00-2.50] is controlled within 45 meters. The effect of controlling and eliminating the head mark is significant, reaching a better control level.

Claims

1. A control method for improving the head mark of a cold-rolled strip coiler, characterized in that: By using the high elastic sleeve outside the coiling machine mandrel, by setting the tension of the taper tension coiling stage and adjusting the tension of the high tension coiling stage and the low tension coiling stage, the tape head is embedded in the sleeve to eliminate the tape head mark. The specific steps are as follows: Step (1), coiling preparation stage: preset the coiling tension T0 and judge the online strip thickness. When the strip thickness is less than 0.8 mm, adopt the constant tension coiling mode; when the strip thickness is ≥ 0.8 mm, intervene in the taper tension control mode for coiling; Step (2), taper tension winding stage: when the strip is wound around the sleeve to a preset number of turns S1, the strip is tensioned, and the tension is set to T1, S1 turns < 1 turn; Step (3), high tension winding stage: when the strip is wound around the sleeve to a preset number of turns S2, the auxiliary winding stage is completed, and the tension setting is adjusted from T1 to T2, S2 turns < 5 turns; Step (4), when the tension is switched to T2 and the strip is wound around the sleeve to a preset number of turns S3, the tension setting is adjusted from T2 to T0, S3 turns ≥ 5 turns; Step (5), after the tension reaches the set value T0, the coiling is performed at a constant tension T0 until the coiling of the strip steel is completed; In the above steps, T0=t×H×B, where H is the strip thickness in mm; B is the strip width in mm; t is the unit tension of the strip steel grade series in daN / mm²; The tension is T1>T0>T2, T1 is 1.5 to 3.0 times of T0, and T2 is 0.1 to 0.9 times of T0.

2. The control method for improving the head mark of the cold-rolled strip coiler according to claim 1 is characterized in that: During steps (1) to (4), the coiler maintains a constant threading speed v; after entering step (5), the unit speeds up.

3. The control method for improving the head mark of the cold-rolled strip coiler according to claim 2 is characterized in that: The threading speed v is in the range of 30 to 70 m / min.

4. The control method for improving the head mark of a cold-rolled strip coiler according to any one of claims 1 to 3, characterized in that: The sleeve is a rubber sleeve.

5. The control method for improving the head mark of the cold-rolled strip coiler according to claim 4 is characterized in that: A plurality of spiral grooves are distributed on the outer surface of the sleeve.

6. The control method for improving the head mark of the cold-rolled strip coiler according to claim 5 is characterized in that: The inner surface of the sleeve is provided with a plurality of straight grooves.

7. The control method for improving the head mark of the cold-rolled strip coiler according to claim 6 is characterized in that: The groove bodies of the spiral groove and the straight groove are both arc structures.

Images