CN114535310B - Plate shape control method for low-carbon bainite steel - Google Patents
Plate shape control method for low-carbon bainite steel Download PDFInfo
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- CN114535310B CN114535310B CN202210182759.0A CN202210182759A CN114535310B CN 114535310 B CN114535310 B CN 114535310B CN 202210182759 A CN202210182759 A CN 202210182759A CN 114535310 B CN114535310 B CN 114535310B
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- 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
- B21B37/28—Control of flatness or profile during rolling of strip, sheets or plates
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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
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Abstract
A control method for the shape of low-carbon bainite steel aims at solving the problems of high cold correction rate and low shape qualification rate of the existing low-carbon bainite steel in the production process of medium plates. The invention improves the shape accurately from the aspects of casting blank heating uniformity, finish rolling shape control, pre-straightening force, mulpic head-tail shielding edge shielding, hot straightening force and the like, ensures that the cold straightening rate of the low-carbon bainitic steel is lower than 2%, reduces the process cost, reduces the shape rescue cost, and controls the unevenness of the low-carbon bainitic steel to be within 3 mm/m.
Description
Technical Field
The invention belongs to the technical field of metallurgy, and relates to a plate shape control method of low-carbon bainite steel.
Background
The plate shape control is an important index for measuring the production level of the medium plate, and good plate shape control can improve the qualification rate and the yield of the steel plate. Under the severe iron and steel market situation at present, the control level of the steel plate shape is improved, the defect of the steel plate shape is reduced, and the method is an important means for reducing the production cost of enterprises and improving the competitiveness of the enterprises. With the rapid development of medium plates, the technology of controlled cooling after rolling, online quenching and ultra-fast cooling is promoted and applied powerfully, and the low-carbon bainite steel has become a necessary trend in the development of the steel industry. Because the ultra-fast cooling control parameters are more, various factors are comprehensively influenced, the cooling along the longitudinal direction, the transverse direction and the thickness direction of the steel plate cannot reach the expected effect, and thus complicated thermal stress changes are caused, and finally the problem of plate shape defect is formed on the steel plate.
The low-carbon bainite steel belongs to medium-temperature transformation steel, the final cooling temperature is generally lower than 550 ℃, the cooling speed is high, and the internal stress after certain cooling exists, so that the problems in three aspects are mainly solved: firstly, the head-tail deformation resistance after the rolling of the low-carbon bainite steel is different, the head-tail shape of a steel plate mother plate is deteriorated, and the shape defect is larger for a production line without a pre-straightening machine; secondly, the final cooling temperature of the low-carbon bainite steel is low, the internal stress of the steel plate is complex and difficult to control, and plate-shaped defects such as upward convexity, downward concavity, head and tail warping, pot shape and the like appear after cooling; thirdly, when the online quenching temperature is reduced to below 200 ℃, a hot straightening machine cannot be used for leveling, all plate-shaped defects can only be saved or changed in length through heat treatment, so that the production cost is greatly increased and the yield is reduced.
The prior art of medium plate factories produces low-carbon bainitic steel mainly by controlling modes of finish rolling bending roller stringing, cooling water quantity proportioning, straightening and the like to improve the hot rolled plate shape, and the means and the method are single. The existing control level of the shape of the low-carbon bainite steel plate can not meet the requirements of rapid development of manufacturing industry, for example, the unevenness of the steel for bridge structures is required to be controlled within 3mm/1 m. Therefore, a new production process is required to be provided, and the control level of the lower bainite steel plate shape is improved.
Disclosure of Invention
The invention aims to provide a control method for the shape of low-carbon bainite steel, which solves the problems of high cold straightening rate and low shape qualification rate of the existing low-carbon bainite steel in the production process of medium plates. The technical scheme of the invention is as follows:
a plate shape control method of low-carbon bainite steel comprises the following process steps:
(1) Furnace chamber control of a heating furnace: the temperature difference between the upper hearth and the lower hearth is controlled to be 20-40 ℃, and the temperature of the upper hearth is higher than that of the lower hearth by 10-20 ℃;
(2) The rolling force of the final pass of finish rolling is less than or equal to 50000kN, the final pass adopts high-pressure water of a frame to remove phosphorus, and the rolling speed is less than or equal to 4.5m/s;
(3) After rolling, passing through a pre-straightening machine, wherein the straightening force is 20000-25000 kN, and the straightening speed is 1.0-2.0 m/s;
(4) The head and tail shielding is opened for 1-3 groups, and the side shielding is 20-40 mm;
(5) And (3) hot straightening control: the head and tail of the mother board are straightened at a low speed of 0.5 to 1.5m/s, and the straightening force of thermal straightening is 35000 to 45000kN.
The invention has the following effects: the invention improves the shape accurately from the aspects of casting blank heating uniformity, finish rolling shape control, pre-straightening force, mulpic head-tail shielding edge shielding, hot straightening force and the like, ensures that the cold straightening rate of the low-carbon bainitic steel is lower than 2%, reduces the process cost, reduces the shape rescue cost, and controls the unevenness of the low-carbon bainitic steel to be within 3 mm/m. The production method is simple, saves the process cost, has good plate shape and can be suitable for mass production.
Detailed Description
The present invention will be further described with reference to examples.
Embodiment one:
the plate shape control method of the 17.5mm low-carbon bainite steel pipeline steel L485M comprises the following process steps:
(1) Furnace chamber control of a heating furnace: the upper and lower temperature difference of the hearth is controlled to be 35 ℃, and the temperature of the upper hearth is higher than that of the lower hearth by 16 ℃;
(2) The rolling force of the final pass of finish rolling is 42000kN, the final pass adopts high-pressure water of a frame to remove phosphorus, and the rolling speed is 4.2m/s;
(3) After rolling, passing through a pre-straightening machine, straightening force: 22000kN and straightening speed of 1.6m/s;
(4) 2 groups are opened by head and tail shielding, and 25mm is shielded at the edge;
(5) And (3) hot straightening control: the mother board head and tail 350mm adopts low-speed straightening, the straightening speed is 0.8m/s, and the hot straightening force is 38000KN.
Product quality detection results: : the cold correction rate is only 0.56%, and the unevenness of the steel plate is 2mm/m.
Embodiment two:
the plate shape control method of the steel Q500qE for the 12mm low-carbon bainite steel bridge structure comprises the following process steps:
(1) Furnace chamber control of a heating furnace: the upper and lower temperature difference of the hearth is controlled to be 32 ℃, and the temperature of the upper hearth is higher than that of the lower hearth by 17 ℃;
(2) The rolling force of the final pass of finish rolling is 41500kN, the final pass adopts high-pressure water of a frame to remove phosphorus, and the rolling speed is 4.0m/s;
(3) After rolling, passing through a pre-straightening machine, straightening force: 23000kN, straightening speed of 1.2m/s;
(4) 3 groups are opened by head and tail shielding, and 36mm is shielded at the edge;
(5) And (3) hot straightening control: the mother plate is straightened at a low speed of 450mm at a straightening speed of 0.8m/s and a thermal straightening force of 43500kN.
Product quality detection results: the cold correction rate is only 1.1 percent, and the unevenness of the steel plate is 2.5mm/m.
Claims (1)
1. The plate shape control method of the low-carbon bainite steel is characterized by comprising the following process steps of:
(1) Furnace chamber control of a heating furnace: the temperature difference between the upper hearth and the lower hearth is controlled to be 20-40 ℃, and the temperature of the upper hearth is higher than that of the lower hearth by 10-20 ℃;
(2) The rolling force of the final pass of finish rolling is less than or equal to 50000kN, the final pass adopts high-pressure water of a frame to remove phosphorus, and the rolling speed is less than or equal to 4.5m/s;
(3) After rolling, passing through a pre-straightening machine, wherein the straightening force is 20000-25000 kN, and the straightening speed is 1.0-2.0 m/s;
(4) The head and tail shielding is opened for 1-3 groups, and the side shielding is 20-40 mm;
(5) And (3) hot straightening control: the head and tail of the mother board are straightened at a low speed of 0.5 to 1.5m/s, and the straightening force of thermal straightening is 35000 to 45000kN.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210182759.0A CN114535310B (en) | 2022-02-27 | 2022-02-27 | Plate shape control method for low-carbon bainite steel |
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| CN202210182759.0A CN114535310B (en) | 2022-02-27 | 2022-02-27 | Plate shape control method for low-carbon bainite steel |
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| CN114535310B true CN114535310B (en) | 2023-07-14 |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101086051A (en) * | 2007-07-12 | 2007-12-12 | 济南钢铁股份有限公司 | Non-tempering easy-welding super strong steel and its production method |
| CN101096738A (en) * | 2006-06-26 | 2008-01-02 | 舞阳钢铁有限责任公司 | Steel plate with low welding crack sensitivity and production method thereof |
| CN105057402A (en) * | 2015-07-17 | 2015-11-18 | 河北钢铁股份有限公司邯郸分公司 | Hot straightening method for low-carbon bainite steel plate with thickness of 25 mm |
| CN107058898A (en) * | 2017-03-31 | 2017-08-18 | 河钢股份有限公司邯郸分公司 | A kind of Q690D low-carbon bainite steels and its production method |
| CN108296285A (en) * | 2018-02-01 | 2018-07-20 | 湖南华菱湘潭钢铁有限公司 | A kind of milling method of ultralow-carbon bainite steel plate |
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2022
- 2022-02-27 CN CN202210182759.0A patent/CN114535310B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101096738A (en) * | 2006-06-26 | 2008-01-02 | 舞阳钢铁有限责任公司 | Steel plate with low welding crack sensitivity and production method thereof |
| CN101086051A (en) * | 2007-07-12 | 2007-12-12 | 济南钢铁股份有限公司 | Non-tempering easy-welding super strong steel and its production method |
| CN105057402A (en) * | 2015-07-17 | 2015-11-18 | 河北钢铁股份有限公司邯郸分公司 | Hot straightening method for low-carbon bainite steel plate with thickness of 25 mm |
| CN107058898A (en) * | 2017-03-31 | 2017-08-18 | 河钢股份有限公司邯郸分公司 | A kind of Q690D low-carbon bainite steels and its production method |
| CN108296285A (en) * | 2018-02-01 | 2018-07-20 | 湖南华菱湘潭钢铁有限公司 | A kind of milling method of ultralow-carbon bainite steel plate |
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