CN117206341A - Method for improving rolling stability of finishing mill - Google Patents
Method for improving rolling stability of finishing mill Download PDFInfo
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- CN117206341A CN117206341A CN202311179807.1A CN202311179807A CN117206341A CN 117206341 A CN117206341 A CN 117206341A CN 202311179807 A CN202311179807 A CN 202311179807A CN 117206341 A CN117206341 A CN 117206341A
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- 238000005096 rolling process Methods 0.000 title claims abstract description 110
- 238000000034 method Methods 0.000 title claims abstract description 12
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 43
- 239000010959 steel Substances 0.000 claims abstract description 43
- 230000005540 biological transmission Effects 0.000 claims description 18
- 238000012423 maintenance Methods 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 description 12
- 238000012360 testing method Methods 0.000 description 3
- 239000002699 waste material Substances 0.000 description 3
- 239000010935 stainless steel Substances 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 238000007619 statistical method Methods 0.000 description 2
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000010962 carbon steel Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
- 230000036967 uncompetitive effect Effects 0.000 description 1
Classifications
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/10—Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working
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- Control Of Metal Rolling (AREA)
Abstract
The invention relates to the field of finish rolling, in particular to a method for improving the rolling stability of a finish rolling machine, which is used for determining the steel grade and the thickness of a steel plate to be rolled by the finish rolling machine after rolling, and if the steel grade is one of T700L, T600L, TQ MCD and TQ600MCD (high-strength steel) and the thickness of the rolled steel plate is less than or equal to 2.5mm (thin-specification product), the finish rolling centering curve is indirectly controlled by applying different pressures on two sides of a finish rolling descaling pinch roll, so that the effect of improving the finish rolling stability is achieved.
Description
Technical Field
The invention relates to the field of finish rolling mill rolling, in particular to the field of high-strength steel thin-specification product rolling.
Background
In 2022, the steel productivity of China is seriously excessive, the steel plates face large-area defects, and enterprises are difficult to operate. Under such a large environment, the production of common specification steel grades is uncompetitive and has serious loss. The high-strength steel thin-specification product has high production difficulty and low yield, but the high-strength steel thin-specification product has high selling price and has a profitable space. The rolling stability of the steel grade is not well solved, the functional precision state change of the finish rolling equipment is not completely controlled, so that more finish rolling scrap steel is caused, the rejection rate of a rolling line is high, the rolling line is not planned to be changed to be thick, the cost is high, and the profitability of the steel grade specification cannot be exerted. Therefore, the production stability of the thin high-strength steel is solved, the yield is improved, and the mass stable production is realized with great significance and is urgent.
Disclosure of Invention
The technical problems to be solved by the invention are as follows: how to solve the problem of poor production stability of high-strength steel thin-specification products.
The technical scheme adopted by the invention is as follows: a method for improving the rolling stability of finishing mill includes such steps as determining the steel grade of steel plate to be rolled by finishing mill and the thickness after rolling, and if the steel grade is one of T700L, T600L, TQ MCD and TQ600MCD (high-strength steel) and the thickness after rolling is less than or equal to 2.5mm (thin-specification product), indirectly controlling the finish rolling centering curve by applying different pressures to both sides of the finish rolling descaling pinch roller.
When different pressures are applied to the two sides of the finish rolling descaling pinch roll, namely when the pressure difference of the two sides of the finish rolling descaling pinch roll is changed, the pressure difference of the two sides of the finish rolling small vertical roll is also changed, the pressure difference of the two sides of the finish rolling small vertical roll directly causes the change of a finish rolling centering curve, in the rolling process, when the pressure difference of the two sides of the finish rolling small vertical roll exceeds 200KN, the finish rolling centering curve can deviate by more than 20mm, running off rolling of scrap steel among frames is extremely easy to occur, at the moment, the side pressure of the transmission of the finish rolling descaling pinch roll is required to be adjusted, and when the side pressure of the transmission of the finish rolling descaling pinch roll is adjusted, the pressure difference of the two sides of the finish rolling small vertical roll is smaller than 180KN.
In each maintenance period of the finishing mill, the transmission side pressure of the finish rolling descaling pinch roll is adjusted, when the maintenance period is less than or equal to 15 days, the rolling stability of the whole maintenance period can be ensured, and the adjustment meets the formula P Adjustment amount =（ P Small vertical roller -150 KN)/40, wherein P Adjustment amount For the adjustment of the side pressure of the transmission of a finish rolling descaling pinch roll, the unit is KN, P Small vertical roller The unit is KN for the actual pressure of the transmission side of the finish rolling small vertical roll.
And an adjusting functional block is added in a PLC control program to realize the on-line adjustment of the pressure at two sides of the pinch roll of the descaling box, and the P adjusting quantity which can be manually input, the pressure difference at two sides of the small finish rolling vertical roll and the actual pressure P small finish rolling vertical roll at the transmission side of the small finish rolling vertical roll are displayed on a PLC display.
The beneficial effects of the invention are as follows: the method effectively improves the rolling stability of the thin gauge high-strength steel rolled by the finishing mill, and reduces the rejection rate of the finishing mill rolling line from 1.95% to 0.60%.
Drawings
FIG. 1 is a finish rolling centering graph without employing the method of the present invention;
FIG. 2 is a finish rolling centering graph employing the method of the present invention;
wherein, 1, a small finish rolling vertical roller transmission side pressure curve, 2, a monotonic curve, 3 and a finish rolling deviation curve.
Detailed Description
The Shanxi Tai steel stainless steel product line 2250 produces high-strength steel thin specifications (T700L/T600L/TQ 700MCD/TQ600MCD and other steel types, the thickness is less than or equal to 2.5 mm), the finish rolling stability is not good, the number of scrap steel is more than 15 each year, and the rejection rate of the finish rolling line is more than 1.2%. In the production process, 2 persons are required for finish rolling on the bench (1 person for normal variety), 3 persons under the bench watch board shape prevents the wave generation and deviation among the racks, and the production difficulty is extremely high.
Technical problems to be solved:
the rolling stability of the finishing mill is improved under the condition that the functional precision of finishing mill equipment cannot be improved rapidly, and the problem of off-tracking steel scraps in the rolling process is solved.
The technical scheme is as follows:
by establishing a attack team, in-situ actual tracking is performed in the production process, production actual data, various rolling parameters and equipment parameter curves are verified, and analysis and research are performed by combining the characteristic of high-strength stainless steel difficult-to-roll material finish rolling stability, so that a key point affecting the deviation problem of the high-strength carbon steel finishing mill is a finish rolling descaling box pinch roll.
Early test
And (3) performing a preliminary production test, wherein in the process of producing the T700L thin gauge, the pressure adjustment on two sides of the finish rolling descaling box is performed manually through a table top operation key, and the actual pressure of the finish rolling small vertical roll and the actual position of the finish rolling centering curve are observed and recorded.
Statistical analysis of data
In one embodiment, as shown in fig. 1, the side pressure curve 1 of the fine rolling small vertical roll is shown, the side pressure of the fine rolling small vertical roll is increased from 171.4 to 205.5KN, the side pressure of the fine rolling off tracking curve 3 is offset from the working side by 35.3mm, and an operator is forced to adjust monotone 20 times so as to avoid off tracking steel scraps.
And through a plurality of test data statistical analyses, the pressure difference at two sides of the small finish rolling vertical roll exceeds 200KN, the finish rolling centering curve can deviate by more than 20mm, and the running and rolling of waste steel among frames are easy to occur. The side pressure of the transmission is increased by the pinch rolls of the finish rolling scale box, so that the side pressure of the transmission of the small finish rolling vertical rolls can be reduced, when the pressure is reduced to below 180KN, the total curve can be controlled to be +/-20 mm, and when the pressure of the fine descaling pinch rolls is adjusted to 10KN, the pressure of the small finish rolling vertical rolls can be changed by 30-50KN. In one embodiment, as shown in fig. 2, the small vertical roll transmission side pressure curve 1 of the finish rolling shows that the transmission side pressure of the small vertical roll is controlled within 200KN, the deviation curve of the finish rolling is within +/-20 mm, and the operator does not need to intervene in the rolling process, so that the rolling is stable.
Developing control functions
Manual adjustment is accidental, on one hand, labor cost is increased, and on the other hand, unstable scrap steel during finish rolling is possibly caused by larger or smaller adjustment amount. It is therefore necessary to develop an automatic adjustment function. The pressure parameter value of the finish rolling descaling pinch roll can be quickly modified in real time in the production process, so that the pressure difference at two sides can be accurately controlled.
Implementation rules: the finish rolling backing roll and finish rolling mill equipment periodic replacement maintenance can be changed every time overhauling, the rolling state of the finish rolling mill changes, the steel grade with the specification is produced for the first time, the adjustment quantity of the finish rolling descaling pinch roll is calculated by observing the actual pressure at two sides of the small vertical roll of the monitoring picture, and the adjustment quantity is adjusted in real time in a program, so that the rolling stability of the whole overhauling period (about 15 days) is basically ensured.
P Adjustment amount =（ P Small vertical roller -150）/40
Wherein:
P adjustment amount : the transmission side pressure adjustment quantity of the finish rolling descaling pinch roll can be input in a program.
P Small vertical roller : the actual pressure of the finish rolling small vertical roll can be monitored in real time in production.
After the invention is formally put into use in 9 months in 2022, the rolling stability of the high-strength steel sheet gauge of a finishing mill is effectively improved, the number of finish-rolled waste steel blocks is reduced from 1.33 blocks/month to 0.57 blocks/month, and the rejection rate of a finish-rolled line is reduced from 1.95% to 0.60%.
1. The high-strength steel thin gauge (thickness is less than or equal to 2.5 mm) difficult to be rolled is calculated according to the yield of 1500 tons per month, and the difference between the scrap steel and the finished product is 2500 yuan/ton, so that the cost can be saved by 1500 x (1.95% -0.60%). 2500 x 12 = 60.75 ten thousand yuan per year.
2. The refractory rolled steel with thin gauge (thickness less than or equal to 2.5 mm) has a fault time of 1 hour per waste steel, a machine hour yield of 710 tons, a per ton profit of 500 yuan, and a annual yield increase of 710 x 1 x (1.33-0.57) x 12 x 500= 323.76 ten thousand yuan.
3. The steel is contained in the roller of the finishing mill by each time of scrap steel of the high-strength steel thin gauge (the thickness is less than or equal to 2.5 mm), the grinding lower amount of F1-F4 is 1.2mm, the millimeter single weight is 175.29Kg/mm, the millimeter unit price is 25 yuan/Kg, the grinding lower amount of F5-F7 is 2mm, the millimeter single weight is 141.42Kg/mm, and the millimeter unit price is 12 yuan/Kg. The roller consumption cost can be saved throughout the year: (8.1.2.175.29+6.2.141.42.12) (1.33-0.57) 12= 56.94 kiloyuan.
The total annual onset of action: 60.75 + 323.76 + 56.94 = 441.45 ten thousand yuan.
Claims (4)
1. A method for improving the rolling stability of a finishing mill, which is characterized by comprising the following steps: and determining the steel grade of the steel plate to be rolled by the finishing mill and the thickness after rolling, and if the steel grade is one of T700L, T600L, TQ MCD and TQ600MCD and the thickness after rolling is less than or equal to 2.5mm, indirectly controlling the finish rolling centering curve by applying different pressures on two sides of the finish rolling descaling pinch roll, thereby achieving the effect of improving the finish rolling stability.
2. A method for improving rolling stability of a finishing mill according to claim 1, wherein: when different pressures are applied to the two sides of the finish rolling descaling pinch roll, namely when the pressure difference of the two sides of the finish rolling descaling pinch roll is changed, the pressure difference of the two sides of the finish rolling small vertical roll is also changed, the pressure difference of the two sides of the finish rolling small vertical roll directly causes the change of a finish rolling centering curve, in the rolling process, when the pressure difference of the two sides of the finish rolling small vertical roll exceeds 200KN, the finish rolling centering curve can deviate by more than 20mm, running off rolling of scrap steel among frames is extremely easy to occur, at the moment, the side pressure of the transmission of the finish rolling descaling pinch roll is required to be adjusted, and when the side pressure of the transmission of the finish rolling descaling pinch roll is adjusted, the pressure difference of the two sides of the finish rolling small vertical roll is smaller than 180KN.
3. A method for improving rolling stability of finishing mill according to claim 2, wherein: in each maintenance period of the finishing mill, the transmission side pressure of the finish rolling descaling pinch roll is adjusted, when the maintenance period is less than or equal to 15 days, the rolling stability of the whole maintenance period can be ensured, and the adjustment meets the formula P Adjustment amount =（ P Small vertical roller -150 KN)/40, wherein P Adjustment amount For the adjustment of the side pressure of the transmission of a finish rolling descaling pinch roll, the unit is KN, P Small vertical roller The unit is KN for the actual pressure of the transmission side of the finish rolling small vertical roll.
4. A method of improving the rolling stability of a finishing mill according to claim 3, wherein: and an adjusting functional block is added in a PLC control program to realize the on-line adjustment of the pressure at two sides of the pinch roll of the descaling box, and the P adjusting quantity, the pressure difference at two sides of the small finish rolling vertical roll and the actual pressure P small vertical roll at the transmission side of the small finish rolling vertical roll which can be manually input are displayed on a PLC display.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311179807.1A CN117206341A (en) | 2023-09-13 | 2023-09-13 | Method for improving rolling stability of finishing mill |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311179807.1A CN117206341A (en) | 2023-09-13 | 2023-09-13 | Method for improving rolling stability of finishing mill |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117206341A true CN117206341A (en) | 2023-12-12 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311179807.1A Pending CN117206341A (en) | 2023-09-13 | 2023-09-13 | Method for improving rolling stability of finishing mill |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117206341A (en) |
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2023
- 2023-09-13 CN CN202311179807.1A patent/CN117206341A/en active Pending
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