CN117753798A - Operation method for reducing contusion defect of flat surface of thin strip steel - Google Patents
Operation method for reducing contusion defect of flat surface of thin strip steel Download PDFInfo
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- CN117753798A CN117753798A CN202311775059.3A CN202311775059A CN117753798A CN 117753798 A CN117753798 A CN 117753798A CN 202311775059 A CN202311775059 A CN 202311775059A CN 117753798 A CN117753798 A CN 117753798A
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- Prior art keywords
- uncoiler
- strip steel
- contusion
- defect
- tension
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 58
- 239000010959 steel Substances 0.000 title claims abstract description 58
- 208000034656 Contusions Diseases 0.000 title claims abstract description 27
- 230000009519 contusion Effects 0.000 title claims abstract description 26
- 230000007547 defect Effects 0.000 title claims abstract description 25
- 238000000034 method Methods 0.000 title claims abstract description 24
- 238000005507 spraying Methods 0.000 claims description 6
- 238000005303 weighing Methods 0.000 claims description 6
- 208000034526 bruise Diseases 0.000 claims 1
- 230000009286 beneficial effect Effects 0.000 abstract description 2
- 238000005516 engineering process Methods 0.000 abstract description 2
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
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Abstract
The invention relates to an operation method for reducing the contusion defect of the flat surface of a thin strip steel, belonging to the technical field of hot rolled strip steel flattening technology in the metallurgical industry. The technical proposal is as follows: when the uncoiler builds tension, the time for increasing the tension from 0 to a set value is 2-3 s, and the leveling speed of the leveling machine is controlled below 250 m/min; the tension set value of the uncoiler is 40-50kN, when the uncoiler leaves 200-250m strip steel, the tension of the uncoiler is reduced to 30-35kN, when the uncoiler leaves 200-250m strip steel, the leveling speed of the leveling machine starts to be reduced, and the reducing slope is 0.136m/s 2 . The beneficial effects of the invention are thatThe method comprises the following steps: the contusion defect on the surface of the thin strip steel with the thickness less than or equal to 3.0mm in the flattening process can be reduced, so that the surface quality of the steel coil and the yield of the steel coil are improved, and the cutting loss is reduced.
Description
Technical Field
The invention relates to an operation method for reducing the contusion defect of the flat surface of a thin strip steel, belonging to the technical field of hot rolled strip steel flattening technology in the metallurgical industry.
Background
In recent years, with the mass application of steel in the fields of automobile industry, ship industry, building industry and the like, the quality requirements of customers on the shape of hot rolled steel strips are also continuously improved. Therefore, it is important to improve the quality of the steel coil plate shape by the hot rolling leveling process.
Various surface quality problems are generated in the process of flattening the steel coil, wherein the surface quality of the steel coil is most seriously affected by surface contusion defects. Compared with a steel coil with a thick specification, the steel coil with a thin specification with the thickness less than or equal to 3.0mm has the quality problem that surface contusion defect is more likely to occur in the flattening process.
The contusion is caused by looseness in the steel coil and relative displacement between layers, and the surface contusion defect mainly occurs on the thin-specification strip steel with the thickness less than or equal to 3.0mm, and the surface contusion defect occurs on the thick-specification strip steel less. The surface contusion defect not only affects the use, but also greatly reduces the yield of the steel coil, and the quality loss is caused by cutting.
Disclosure of Invention
The invention aims to provide an operation method for reducing the contusion defect of the flat surface of a thin strip steel, which can reduce the contusion defect of the surface of the thin strip steel with the thickness less than or equal to 3.0mm in the flattening process and solve the problems in the prior art.
The technical scheme of the invention is as follows:
an operation method for reducing the contusion defect of the flat surface of a thin strip steel comprises the following steps: uncoiling by an uncoiler, threading, straightening machine, leveling machine, coiling by a coiling machine, bundling, weighing, number spraying, and steel coil warehousing, wherein the uncoiling, threading, straightening machine, leveling machine, coiling machine, bundling, weighing, number spraying and steel coil warehousing are controlled according to the following requirements:
a. when the uncoiler builds tension, the time for increasing the tension from 0 to a set value is 2-3 s;
b. the leveling speed of the leveling machine is controlled below 250 m/min.
The operation method for reducing the contusion defect of the flat surface of the thin strip steel has the tension set value of 40-50kN.
According to the operation method for reducing the contusion defect of the flat surface of the thin strip steel, when 200-250m strip steel is left on the uncoiler, the tension of the uncoiler is reduced to 30-35kN.
The operation method for reducing the contusion defect of the flat surface of the thin strip steel comprises the steps that when 200-250m strip steel is left on an uncoiler, the leveling speed of the leveling machine begins to be reduced, and the reducing speed slope is 0.136m/s 2 。
The beneficial effects of the invention are as follows: the contusion defect on the surface of the thin strip steel with the thickness less than or equal to 3.0mm in the flattening process can be reduced, so that the surface quality of the steel coil and the yield of the steel coil are improved, and the cutting loss is reduced.
Detailed Description
An operation method for reducing the contusion defect of the flat surface of a thin strip steel comprises the following steps: uncoiling by an uncoiler, threading, straightening machine, leveling machine, coiling by a coiling machine, bundling, weighing, number spraying, and steel coil warehousing, wherein the uncoiling, threading, straightening machine, leveling machine, coiling machine, bundling, weighing, number spraying and steel coil warehousing are controlled according to the following requirements:
a. when the uncoiler builds tension, the time for increasing the tension from 0 to a set value is 2-3 s;
b. the leveling speed of the leveling machine is controlled below 250 m/min.
The tension set value of the uncoiler is 40-50kN.
When 200-250m strip steel remains in the uncoiler, the tension of the uncoiler is reduced to 30-35kN.
When 200-250m strip steel is remained in the uncoiler, the leveling speed of the leveling machine begins to be reduced, and the reducing speed slope is 0.136m/s 2 。
In this example, the hot rolled strip was Q235B, 2.00mm thick and 1250mm wide, and the core of the batch of hot rolled coil was significantly loosened and slightly oval in coil shape.
The leveling process comprises the following steps: uncoiling by an uncoiling machine, threading, straightening machine, leveling machine, coiling by a coiling machine, bundling, weighing, number spraying, steel coil warehousing,
according to the conventional operation, the tension of the coiling machine is set to 55kN, after the threading and the tension building, the speed of the leveling machine is gradually increased to 300m/min after the startup, and the speed is 0.17m/s when the tail of the belt is 200m 2 The slope of (c) is slowed down to 100 m/min. When 40 meters from the core of the steel coil, the steel coil is stopped, the upper surface and the lower surface of the steel coil are inspected in a stepwise manner, obvious contusion defects are found, the closer to the core, the more obvious the contusion conditions are, and the more the positions are.
According to the invention, the tension set value is 40-50kN, the tension is gently changed when uncoiling and building, the tension is increased from 0 to 40-50 and needs 2-3 s, the tension of an uncoiler of a thin steel coil is always kept at 40-50kN before and during the middle period of flattening, and the tension of the uncoiler is reduced to 30-35kN when the strip steel in the later period of flattening is 200-250 m; in addition, when the thin strip steel is leveled, the uncoiling speed is too high, the uncoiling tension is caused to be severely fluctuated, so that the strip coil slides between layers, therefore, the leveling speed is properly controlled to be below 250m/min, and simultaneously, when the strip steel in the later period is leveled to be 200-250m meters, the deceleration is started, and the deceleration slope is changed from 0.17m/s 2 Reduced to 0.136m/s 2 . The deceleration slope is the leveling speed variation in unit time, and the deceleration slope is reduced by 20%. And when the distance from the core of the steel coil to the core is 40 meters, stopping the steel coil to perform staged inspection on the upper surface and the lower surface of the steel coil, and not finding the contusion defect until the steel is thrown to the core, and still not finding the contusion defect.
Claims (4)
1. An operation method for reducing the contusion defect of the flat surface of a thin strip steel comprises the following steps: uncoiling by an uncoiler, threading, straightening machine, leveling machine, coiling by a coiling machine, bundling, weighing, number spraying and steel coil warehousing, and is characterized in that the uncoiling is controlled according to the following requirements:
a. when the uncoiler builds tension, the time for increasing the tension from 0 to a set value is 2-3 s;
b. the leveling speed of the leveling machine is controlled below 250 m/min.
2. The method for reducing the contusion defect on the flat surface of the thin gauge strip steel according to claim 1, wherein the method comprises the following steps: the tension set value of the uncoiler is 40-50kN.
3. The method for reducing the contusion defect on the flat surface of the thin gauge strip steel according to claim 2, wherein the method comprises the following steps: when 200-250m strip steel remains in the uncoiler, the tension of the uncoiler is reduced to 30-35kN.
4. The method of claim 3, wherein the step of reducing the flat surface bruise defect of the thin gauge strip comprises: when 200-250m strip steel remains in the uncoiler, the leveling speed of the leveling machine begins to be reduced, and the reducing speed slope is 0.136m/s 2 。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311775059.3A CN117753798A (en) | 2023-12-22 | 2023-12-22 | Operation method for reducing contusion defect of flat surface of thin strip steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311775059.3A CN117753798A (en) | 2023-12-22 | 2023-12-22 | Operation method for reducing contusion defect of flat surface of thin strip steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117753798A true CN117753798A (en) | 2024-03-26 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311775059.3A Pending CN117753798A (en) | 2023-12-22 | 2023-12-22 | Operation method for reducing contusion defect of flat surface of thin strip steel |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117753798A (en) |
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2023
- 2023-12-22 CN CN202311775059.3A patent/CN117753798A/en active Pending
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