CN115415330A - Hot rolling laminar cooling control method - Google Patents
Hot rolling laminar cooling control method Download PDFInfo
- Publication number
- CN115415330A CN115415330A CN202211153349.XA CN202211153349A CN115415330A CN 115415330 A CN115415330 A CN 115415330A CN 202211153349 A CN202211153349 A CN 202211153349A CN 115415330 A CN115415330 A CN 115415330A
- Authority
- CN
- China
- Prior art keywords
- steel
- laminar
- time period
- flow control
- control time
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
- B21B37/16—Control of thickness, width, diameter or other transverse dimensions
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Control Of Metal Rolling (AREA)
Abstract
The invention aims to disclose a hot-rolled laminar cooling control method, which is characterized in that aiming at the hot-rolled coiling time period of the whole coil of steel, a laminar cooling area is divided into a first laminar flow control time period, a second laminar flow control time period and a third laminar flow control time period, 70-90% of the laminar cooling area is opened in the first laminar flow control time period, the whole laminar flow cooling area is opened in the second laminar flow control time period, and 70-90% of the laminar cooling area is opened in the third laminar flow control time period; the invention has the beneficial effects that: the hot rolled steel is cooled according to time periods, a laminar cooling area of 70-90% is opened in the first laminar flow control time period, all laminar cooling areas are opened in the second laminar flow control time period, and a laminar cooling area of 70-90% is opened in the third laminar flow control time period, so that the temperature of the head, the tail and the middle of the steel is kept consistent in the cooling process after coiling, the thickness of the head, the tail and the middle of the steel after cold rolling and acid rolling is ensured to be relatively consistent, and the thickness difference of a cold rolling high-strength steel acid rolling bell mouth is improved.
Description
Technical Field
The invention relates to the technical field of steel smelting, in particular to a hot-rolling laminar cooling control method.
Background
After the cold-rolled high-strength steel is subjected to hot rolling and coiling, the head and the tail of the steel are inconsistent in cooling speed, so that the bell mouth thickness difference is easily generated on the steel subjected to cold rolling and acid rolling, the thicknesses of the head and the tail of the steel exceed the standard, and the head and the tail with the standard thicknesses are generally required to be repaired and cut off. At present, the method for controlling the consistent thickness of the head and the tail of rolled steel comprises a method for flattening and cutting the head and the tail of a hot rolled coil to ensure that the thickness difference of a bell mouth after cold rolling is controllable, and the method has the defects of higher cost, low comprehensive yield and easy generation of additional defects; secondly, the method for cutting off the bell mouth thickness difference part of the hot rolled cold hard coil or the finished steel coil has the advantages of higher cost and low comprehensive yield.
In view of this, it is necessary to develop a method capable of precisely controlling the thickness difference of the cold-rolled high-strength steel bell mouth to improve the pass rate of the thickness of the finished product and reduce the cutting loss, so as to overcome the above-mentioned defects.
Disclosure of Invention
The invention aims to disclose a hot rolling laminar cooling control method, which divides a laminar cooling area according to time periods, carries out different cooling on the head part, the middle part and the tail part of steel respectively, and realizes coiling the head part, the middle part and the tail part of the steel under different temperature conditions, thereby ensuring that the head and the tail of the steel are qualified in thickness after cold rolling and acid rolling.
In order to achieve the purpose, the invention provides a hot rolling laminar cooling control method, aiming at the hot rolling coiling time period of the whole coil of steel, a laminar cooling area is divided into a first laminar flow control time period, a second laminar flow control time period and a third laminar flow control time period, a laminar flow cooling area of 70-90% is opened in the first laminar flow control time period, the whole laminar flow cooling area is opened in the second laminar flow control time period, and a laminar flow cooling area of 70-90% is opened in the third laminar flow control time period.
Preferably, the first layer control time period duration T 1 =L 1 V, wherein L 1 The length of the head steel of the whole rolled steel is measured, and V is the running speed of the laminar cooling section of the steel.
Preferably, said L 1 =10m-30m。
Preferably, the second laminar flow control time period duration T 2 =L 2 V, wherein L 2 The length of the steel material in the middle of the whole coil of the steel material, and V is the running speed of the laminar cooling section of the steel material.
Preferably, said L 2 =300m-1000m。
Preferably, the third tier flow control time period duration T 3 =L 3 V, wherein L 3 The length of the tail steel of the whole coil of steel is shown, and V is the running speed of the laminar cooling section of the steel.
Preferably, said L 3 =10m-30m。
Preferably, the previous procedure of laminar cooling is finish rolling, and the finish rolling temperature of the finish rolling is 800-950 ℃.
Preferably, the temperature of the middle part of the steel coiling is 400-700 ℃.
Preferably, the tail temperature of the steel is 30 ℃ higher than the middle temperature of the steel.
Preferably, the temperature of the head of the steel material is 30 ℃ higher than the temperature of the middle of the steel material.
Compared with the prior art, the invention has the beneficial effects that:
the hot rolled steel is respectively cooled according to time periods, specifically, a laminar flow cooling area of 70-90% is opened in a first laminar flow control time period, all laminar flow cooling areas are opened in a second laminar flow control time period, and a laminar flow cooling area of 70-90% is opened in a third laminar flow control time period, so that the temperature of the head of the steel cooled in the first laminar flow control time period is higher than that of the middle of the steel, the head of the steel is lower than that of the middle of the steel due to fast heat dissipation of a coiling mandrel, the temperature of the head and the middle of the steel is kept consistent after the steel is coiled, and the thickness of the head and the middle of the steel is kept consistent after the steel is cold rolled and acid rolled; similarly, the temperature of the tail part of the steel cooled in the third layer of flow control time period is higher than that of the middle part of the steel, so that the temperature of the tail part of the steel is lower than that of the middle part of the steel due to the fact that the tail part of the steel dissipates heat to the air quickly is offset, the temperature of the tail part of the steel is kept consistent with that of the middle part of the steel after coiling, and the thickness of the tail part of the steel is kept consistent with that of the middle part of the steel after cold rolling and acid rolling.
Drawings
FIG. 1 is a view showing the difference in bell-mouth thickness of a steel coil after cold rolling and acid rolling in the prior art.
FIG. 2 is a view of the bell mouth thickness difference of the steel coil after the cold rolling and the acid rolling.
FIG. 3 is a temperature curve of the head, middle and tail of the steel coiling according to the prior art.
FIG. 4 is the temperature curves of the head, middle and tail of the process of the invention.
FIG. 5 is a graph showing the temperature curves of the head, middle and tail portions of the rolled steel material according to the prior art.
FIG. 6 is a graph showing the temperature curves of the head, middle and tail portions of the process of the present invention.
Detailed Description
The present invention is described in detail with reference to the embodiments shown in the drawings, but it should be understood that these embodiments are not intended to limit the present invention, and those skilled in the art should understand that functional, methodological, or structural equivalents or substitutions made by these embodiments are within the scope of the present invention.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations or positional relationships based on those shown in the drawings, merely for convenience of description and simplification of the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be construed as limiting the present invention.
The following describes a specific implementation process of the present invention by using a plurality of embodiments.
The first embodiment is as follows:
the embodiment I provides a hot-rolled laminar cooling control method, aiming at a hot-rolled coiling time period of a whole coil of steel, a laminar cooling area is divided into a first layer flow control time period, a second layer flow control time period and a third layer flow control time period, a laminar cooling area of 70% -90% is opened in the first layer flow control time period, all laminar cooling areas are opened in the second layer flow control time period, and a laminar cooling area of 70% -90% is opened in the third layer flow control time period.
Specifically, fig. 1 shows the thickness difference generated in the length direction after the steel material is subjected to cold rolling and acid rolling in the conventional hot rolling laminar cooling process, and it can be found that the thickness difference between the steel material at the head and the tail of the steel material is relatively large, while the thickness difference between the steel material at the middle of the steel material is relatively stable, so that a thickness difference similar to a bell mouth, referred to as a bell mouth thickness difference, is formed.
The reason why the aforementioned bell-mouth thickness difference occurs is that: 1) The coiling temperature of the hot-rolled steel coil is about 400-700 ℃ due to the coiling process and coiling equipment factors after hot rolling, the head (inner ring) of the steel coil is cooled quickly inevitably due to heat transfer of a mandrel in the coiling process of the steel coil, and the head and the tail (inner ring and outer ring) of the steel coil are cooled quickly due to contact with air after the hot-rolled steel coil is uncoiled from a coiling machine. Therefore, the head and the tail of the steel coil have temperature difference, which causes the performance difference of the head, the middle and the tail of the steel coil, and further shows that the thickness difference of the head, the middle and the tail of the steel coil fluctuates after the steel is cold-rolled and acid-rolled, the performance requirements are exceeded in severe cases, and the head and the tail can only be subjected to waste cutting treatment.
In order to overcome the thickness difference fluctuation of the head, the middle and the tail of a steel coil after cold rolling and acid rolling of steel, aiming at the hot rolling and coiling time period of the whole coil of steel, a laminar cooling area is divided into a first layer flow control time period, a second layer flow control time period and a third layer flow control time period, and in the three time periods, laminar cooling areas with different cooling water flows are respectively opened; starting 70% -90% of the laminar cooling area in the first laminar flow control time period, namely starting 70% -90% of the normal cooling water flow of the laminar cooling area, so that the cooling water flow is reduced by 10% -30%, and the temperature of the steel cooled in the first laminar flow control time period, namely the temperature of the head of the steel is higher than that of the steel with the normal cooling water flow; starting all laminar cooling areas in the second laminar flow control time period, namely starting normal cooling water flow of the laminar cooling areas completely, so that the temperature of steel cooled in the second laminar flow control time period, namely the temperature of the middle part of the steel is equal to that of the steel with the normal cooling water flow; and starting 70-90% of the laminar cooling area in the third layer of flow control time period, namely starting 70-90% of the normal cooling water flow of the laminar cooling area, so that the cooling water flow is reduced by 10-30%, and the temperature of the steel cooled in the third layer of flow control time period, namely the temperature of the tail part of the steel is higher than that of the steel with the normal cooling water flow.
Through the embodiment, the temperature of the head of the steel material cooled in the first laminar flow control time period is higher than that of the middle part of the steel material, so that the temperature of the head of the steel material is lower than that of the middle part of the steel material due to rapid heat dissipation of the coiling mandrel, the temperature of the head and the middle part of the steel material is kept consistent after coiling, and the thickness of the head and the middle part of the steel material is relatively consistent after the steel coil is subjected to cold rolling and acid rolling; similarly, the temperature of the tail part of the steel cooled in the third layer of flow control time period is higher than that of the middle part of the steel, so that the temperature of the tail part of the steel is lower than that of the middle part of the steel due to the fact that the tail part of the steel dissipates heat to the air quickly, the temperature of the tail part of the steel is kept consistent with that of the middle part of the steel after coiling, and the thickness of the tail part of the steel and the thickness of the middle part of the steel after the steel coil is subjected to cold rolling and acid rolling are relatively consistent.
Head steel length L of general whole coil steel 1 =10m-30m, length L of middle steel 2 =300m-1000m, length L of tail steel 3 =10m-30m; after repeated tests, the thickness at L is compared with the standard thickness under the conventional control 1 And L 3 Within the length range of (2), the thickness difference of the steel is large, and the formed bell mouth is thickSee fig. 1 for differences.
To overcome L 1 And L 3 The first layer flow control time period is controlled by the time length T 1 =L 1 V, wherein L 1 The length of head steel material for whole coil of steel material, V is the running speed of laminar cooling section of steel material, at T 1 In time, starting 70-90% of laminar cooling area, namely starting 70-90% of normal cooling water flow of laminar cooling area, reducing cooling water flow by 10-30%, and enabling T 1 The temperature, T, of the steel cooled over time, i.e. the temperature of the head of the steel being higher than the normal cooling water flow 1 Length of steel cooled in time period L 1 The temperature of the head steel is 30 ℃ higher than that of the middle steel, so as to offset the fact that the head of the steel is lower than the middle temperature of the steel due to rapid heat dissipation of a coiling mandrel, and thus the temperature of the head and the middle of the steel after coiling is kept consistent, and thus the thickness of the head and the middle of the steel after cold rolling and acid rolling of the steel coil is relatively consistent, taking the coiling temperature of the middle steel as 590 ℃, for example, refer to the temperature curve diagrams 3 of the head, the middle and the tail of the existing coiling process before coiling, and the temperature curve diagrams 4 of the head, the middle and the tail of the coiling process of the embodiment before coiling, wherein the temperature of the middle is 590 ℃, and the temperature of the head and the tail of the coiling process is 620 ℃.
It is further noted that the middle temperature is 590 ℃ which is the target temperature, the head and tail temperatures of the coiling process are 620 ℃ which are also the target temperatures, the head and tail steel temperatures are 30 ℃ higher than the middle steel temperature, and the actual temperature curve of the target temperatures is fluctuated and is normal within the range of +/-18 ℃.
Similarly, the time period T of the third layer flow control is controlled 3 =L 3 V, wherein L 3 The length of tail steel material of whole roll of steel material, V is the running speed of laminar cooling section of steel material, at T 3 In time, starting 70-90% of laminar cooling area, namely starting 70-90% of normal cooling water flow of laminar cooling area, reducing cooling water flow by 10-30%, and enabling T 3 The temperature of the steel cooled over time, i.e. the temperature of the tail of the steel being higher than normalTemperature of steel material of cooling water flow rate, T 3 Length of steel cooled in time period L 3 The temperature of the tail steel is 30 ℃ higher than that of the middle steel by 10-30 m, preferably 20m, so as to offset the fact that the tail temperature of the steel is lower than the middle temperature of the steel due to rapid heat dissipation to the air, thereby ensuring that the temperatures of the tail and the middle of the steel are kept consistent after the steel is rolled, and further ensuring that the thicknesses of the tail and the middle of the steel after the steel coil is subjected to cold rolling and acid rolling, specifically referring to the temperature curve diagrams 3 of the head, the middle and the tail of the existing coiling process before coiling, and the temperature curve diagrams 4 of the head, the middle and the tail of the coiling process in the embodiment before coiling.
Through the embodiment, the thickness difference of the head part, the middle part and the tail part of the rolled steel is obviously reduced, the scrappage of the head part and the tail part is greatly reduced, the steel is saved, and the cost is controlled.
To further illustrate the process for preparing hot rolled steel, the process comprises the following steps: heating a plate blank → rough descaling with high-pressure water → rough rolling (1020-1150 ℃) → crop end, tail → fine descaling with high-pressure water → finish rolling (800-950 ℃) → laminar cooling → coiling (400-700 ℃) → packaging/spray printing → warehousing.
Example two:
the difference from the first embodiment is that the coiling temperature of the middle steel material in the second embodiment is 545 ℃, specifically referring to the temperature curve diagram 5 of the head, middle and tail of the coiling process in the prior art before coiling, and the temperature curve diagram 6 of the head, middle and tail of the coiling process in the present embodiment before coiling, the temperature of the middle is 545 ℃, and the temperature of the head and tail of the coiling process is 575 ℃.
It is further explained that the middle temperature is 545 ℃ which is the target temperature, the head and tail temperatures of the coiling process are 575 ℃ which is also the target temperature, the head and tail steel temperatures are 30 ℃ higher than the middle steel temperature, the lengths of the head steel and the tail steel are 20m, the actual temperature curve of the target temperature is fluctuated, and the temperature is normal within the range of +/-18 ℃.
The hot-rolling laminar cooling control method disclosed in this embodiment has the same technical solutions as those in embodiment 1, please refer to embodiment 1, and details are not repeated herein.
Claims (10)
1. The hot rolling laminar cooling control method is characterized in that a laminar cooling area is divided into a first laminar flow control time period, a second laminar flow control time period and a third laminar flow control time period aiming at a hot rolling coiling time period of a whole coil of steel, 70% -90% of the laminar cooling area is opened in the first laminar flow control time period, all the laminar cooling areas are opened in the second laminar flow control time period, and 70% -90% of the laminar cooling area is opened in the third laminar flow control time period.
2. The hot rolled laminar cooling control method according to claim 1, characterized in that the first laminar control time period T is a duration T 1 =L 1 V, wherein L 1 The length of the head steel of the whole coil of steel is shown, and V is the running speed of the laminar cooling section of the steel.
3. The hot rolled laminar cooling control method according to claim 2, characterized in that said L 1 =10m-30m。
4. The hot rolled laminar cooling control method according to claim 1, characterized in that the second laminar flow control time period duration T 2 =L 2 V, wherein L 2 The length of the steel material in the middle of the whole coil of the steel material, and V is the running speed of the laminar cooling section of the steel material.
5. The hot rolled laminar cooling control method according to claim 4, characterized in that said L 2 =300m-1000m。
6. The hot rolled laminar cooling control method according to claim 1, characterized in that the third layer flow control time period is of duration T 3 =L 3 V, wherein L 3 The length of the tail steel of the whole rolled steel is measured, and V is the running speed of the laminar cooling section of the steel.
7. The hot rolled laminar cooling control method according to claim 6, characterized in that said L 3 =10m-30m。
8. A hot rolling laminar cooling control method according to any one of claims 1 to 7, characterized in that the preceding step of the laminar cooling is finish rolling, and a finish rolling temperature of the finish rolling is 800 ℃ to 950 ℃.
9. A hot rolled laminar cooling control method according to any one of claims 1 to 7, characterized in that the second laminar flow control steel (middle portion) coiling temperature is 400 to 700 ℃.
10. A hot rolled laminar cooling control method according to claim 2 or 6, characterized in that the temperature of the third layer of flow-controlled steel (tail) is 30 ℃ higher than the temperature of the middle of the steel, and the temperature of the first layer of flow-controlled steel (head) is 30 ℃ higher than the temperature of the middle of the steel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211153349.XA CN115415330A (en) | 2022-09-21 | 2022-09-21 | Hot rolling laminar cooling control method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211153349.XA CN115415330A (en) | 2022-09-21 | 2022-09-21 | Hot rolling laminar cooling control method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115415330A true CN115415330A (en) | 2022-12-02 |
Family
ID=84204925
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211153349.XA Pending CN115415330A (en) | 2022-09-21 | 2022-09-21 | Hot rolling laminar cooling control method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115415330A (en) |
-
2022
- 2022-09-21 CN CN202211153349.XA patent/CN115415330A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6062055A (en) | Rolling method for thin flat products and relative rolling line | |
| CN101528967B (en) | Method for manufacturing flat steel products from a steel forming a martensitic structure | |
| CN101628297A (en) | Reversible hot-rolling process of titanium plate coil | |
| CN111167858A (en) | Method for headless rolling of ferrite area of ultrathin strip steel | |
| JP2000271603A (en) | Hot-rolling method of extra-thin strip and rolling apparatus | |
| CN110153199A (en) | A kind of controlled rolling method of large scale rod bar | |
| US20230241656A1 (en) | Thin strip production process employing continuous casting and rolling | |
| CN104593698B (en) | Method for manufacturing high-strength cold-rolled weather resisting steel plates and high-strength cold-rolled weather resisting steel plates | |
| JP2003320402A (en) | Method and apparatus for manufacturing hot rolled steel strip | |
| CN115415330A (en) | Hot rolling laminar cooling control method | |
| CN112301279A (en) | Production method of hot-rolled round steel for annealing-free low-hardness spring | |
| CN107058896A (en) | A kind of flat volume control method of DP steel Automobile Plate hot rolling | |
| CN106734246A (en) | A kind of method for reducing cold-rolled biphase steel aberration | |
| JPH11123437A (en) | Manufacture of steel sheet having thin scale | |
| JP2005074480A (en) | Facility for producing hot-rolled steel plate, and its production method | |
| JP2004090065A (en) | Heavy reduction rolling method and method for manufacturing hot-rolled steel strip by using the same | |
| CN116060454B (en) | Cold continuous rolling temperature control method for electrical steel | |
| CN104511477A (en) | Thermal mechanical process | |
| JP2611455B2 (en) | Manufacturing method of high carbon cold rolled steel strip | |
| US1842220A (en) | Sheet metal rolling process | |
| JP2000265214A (en) | Production of steel plate as cold-roll excellent in flatness of punched parts | |
| JPS6056403A (en) | Rolling installation for thick steel sheet | |
| JPH0639624B2 (en) | Manufacturing method of high carbon hot rolled steel sheet with excellent cold rolling workability | |
| JP2001058202A (en) | Hot rolling mill, and hot rolling method | |
| JP2819984B2 (en) | Steel strip cooling method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |