CN113695396A - Method for rolling 40-100mm medium plate by using continuous casting billet corner cracks without cleaning and with low trimming cut amount - Google Patents
Method for rolling 40-100mm medium plate by using continuous casting billet corner cracks without cleaning and with low trimming cut amount Download PDFInfo
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- CN113695396A CN113695396A CN202010444648.3A CN202010444648A CN113695396A CN 113695396 A CN113695396 A CN 113695396A CN 202010444648 A CN202010444648 A CN 202010444648A CN 113695396 A CN113695396 A CN 113695396A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/46—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B15/00—Arrangements for performing additional metal-working operations specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
- B21B15/0007—Cutting or shearing the product
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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
- B21B37/56—Elongation control
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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
- B21B37/74—Temperature control, e.g. by cooling or heating the rolls or the product
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B38/00—Methods or devices for measuring, detecting or monitoring specially adapted for metal-rolling mills, e.g. position detection, inspection of the product
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B38/00—Methods or devices for measuring, detecting or monitoring specially adapted for metal-rolling mills, e.g. position detection, inspection of the product
- B21B38/04—Methods or devices for measuring, detecting or monitoring specially adapted for metal-rolling mills, e.g. position detection, inspection of the product for measuring thickness, width, diameter or other transverse dimensions of the product
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
- B21B45/02—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for lubricating, cooling, or cleaning
- B21B45/0203—Cooling
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
- B21B45/04—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for de-scaling, e.g. by brushing
- B21B45/08—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for de-scaling, e.g. by brushing hydraulically
Abstract
The invention discloses a method for rolling a medium plate with the thickness of 40-100mm by using continuous casting blank corner cracks without cleaning and with low trimming cut amount, belonging to the technical field of steel making and steel rollingThe quality of the casting blank is checked before the casting blank is heated, and the quality check content comprises the actual width B of the casting blank0And width B of corner cracks on both sides of the casting blank1、B2And (4) measuring, and determining whether the casting blank needs to be cleaned according to the width of the crack strip of the casting blank and the rolling width-to-width ratio. The heating and rolling process is controlled to control the flattening width within the design range, so that when the total trimming amount of the two sides of a rolled steel plate is 70-100mm, cracks within 25mm of the single-side edge part of a continuous casting billet are free of cleaning and rolled, the width of the single-side flattening and widening of the steel plate obtained after rolling is controlled within 15mm, a corner crack belt is controlled within the trimming amount range, the steel plate can be cut off during finishing, the corner crack casting blank cleaning cost is reduced, the yield is greatly improved, and the economic benefit is remarkable.
Description
Technical Field
The invention relates to the technical field of steel making and steel rolling, in particular to a method for rolling a medium plate of 40-100mm in a low trimming amount without cleaning cracks at corners of a continuous casting billet.
Background
The problem of corner transverse cracks of the continuous casting billet is a key quality problem which troubles continuous casting production and is difficult to thoroughly solve in various steel mills, and in order to ensure the quality of rolled steel plates, the off-line corner cleaning treatment is generally required for the continuous casting billet, so that the application of hot charging and hot delivery is restricted, and the contract performance and the production cost are seriously hindered.
Particularly, the problem of corner transverse cracks is common in large-section continuous casting billets with the diameter of 300mm or more. The transverse crack proportion of the continuous casting billet corner of an enterprise reaches about 90 percent, and the cleaning pressure task is huge. The corner cracks of the continuous casting blank are positioned on the edge of the casting blank and are generally within 30mm from the edge; the mass production practice shows that the steel plate cracks directly rolled without cleaning the corner cracks of the continuous casting billet do not appear at the edge of the steel plate, the phenomenon that the cracks move towards the middle is caused, the unilateral inward movement distance of the cracks is between 5 and 40mm, the width of the crack belt is added, the trimming amount at least needs more than 100mm to be cut, particularly, the 30-100mm medium plate is cut, the trimming amount is reduced to 70-100mm, the corner cracks can not be cut basically, and a large number of cracks are not planned, so the casting billet can be rolled after being cleaned.
For the corner cracks of the continuous casting billet, the traditional treatment method is to directly roll the follow-up cut cracks without cleaning by increasing the trimming amount of the steel plate so as to ensure the quality of the steel plate. However, with the cost reduction of enterprises, the large use of rolling vertical rolls and the requirement of improving the rolling yield, the edge cutting amount of the steel plate is reduced from the original value of 100-140mm to 70-100mm, and the cracks of the steel plate rolled by the casting blank are not cleaned, so that the steel plate has to be cleaned completely, and the qualified rate of the steelmaking quality and the contract performance are seriously influenced. Therefore, how to realize the cleaning-free rolling of the angular cracks of the casting blank, improve the yield, reduce the process flow and improve the contract performance rate becomes the research direction of technical personnel.
For example, patent with publication number CN102284482B discloses a method for effectively controlling the transverse edge crack of a medium plate, belonging to the technical field of steel making and rolling. The controlled process parameters are as follows: the continuous casting process comprises the following steps: the accuracy of the base arc roll gap of the sector section of the continuous casting machine is controlled within +/-0.5 mm; the protection casting of the casting machine is ensured, and the nitrogen increasing amount is controlled to be below 5 ppm; and controlling the width size deviation of the billet to be-10-15 mm. The steel rolling process comprises the following steps: controlling the discharging temperature of the steel billet to be 1160-1300 ℃; the width ratio of the rolled steel plate to the width of the steel billet is 1.15-2.1, the trimming quantities of the rolled steel plate and the steel billet are different corresponding to different width ratios, and the single-side trimming allowance is controlled to be 38-63 mm; the compression ratio of the thickness of the steel billet to the thickness of the steel plate is more than 5-25; for medium-carbon Nb-containing steel, the corner crack length is less than 15mm, and the billet with the corner crack of less than 20mm of the steel types such as plain carbon, low alloy and the like can be directly rolled, and the cracks exceeding the limited size must be cleaned or cut off.
The method disclosed by the patent requires a compression ratio of more than 5-25, is mainly suitable for rolling thin plates with the thickness of 10-40mm, and does not provide a clear edge crack control method for steel plates with the rolling compression ratio of only 3-8 for steel plates with the thickness of more than 40 mm; meanwhile, the rolled double-side trimming amount of the patent is 76-126mm, the trimming amount range is large, a calculation formula for setting the trimming amount is not clearly given, and the actual operation and control are not convenient. Meanwhile, the corner cracks of the steel containing Nb in the patent are smaller than 15mm, the corner cracks of the steel types such as ordinary carbon, low alloy and the like are smaller than 20mm, cleaning-free rolling is realized, and the corner cracks above 20mm need to be cleaned and cut.
Disclosure of Invention
Aiming at the problems, through repeated research, the inventor develops a method for rolling a 40-100mm medium plate by using a continuous casting blank corner crack cleaning-free low trimming cut amount, controls the width of single-side flattening and widening in the casting blank rolling process within 15mm, and can realize cleaning-free rolling of a crack within 25mm of a casting blank edge part under the condition that the trimming cut amount of a rolled steel plate is only 70-100mm, so that the corner cleaning cost of the casting blank is reduced, the yield is greatly improved, and the method has good economic benefit.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows:
a method for rolling a medium plate of 40-100mm in a continuous casting blank corner crack cleaning-free low trimming cut amount mode comprises the steps of smelting molten iron and casting to obtain a continuous casting blank, heating, rolling and finishing the casting blank to obtain a finished steel plate, wherein quality inspection needs to be carried out on the casting blank before the casting blank is heated, and quality inspection contents comprise quality inspection of the casting blankActual width of the blank B0And width B of corner cracks on both sides of the casting blank1、B2And (3) measuring, and determining whether the casting blank needs to be cleaned according to the width of the corner crack strip of the casting blank and the rolling width-to-width ratio, wherein a specific judgment formula is as follows:
ΔB＞（B1+B2）*B/B0+C
delta B is the total trimming amount of two edges of the rolled steel plate by lifting material, B0Is the width of the cast slab, B1、B2The widths of cracks at the left corner and the right corner of a casting blank are respectively, B is the rolling width of a steel plate, and C is a constant. The cracks at the corners of the continuous casting billet meet the requirements of the judging formula, and the continuous casting billet can be directly charged and rolled without being cleaned.
Further, the constant C can alternatively be between 10mm and 40mm, generally related to the reduction ratio, the steel thickness, the rolling reduction, the rolling temperature and the rolling friction coefficient. However, for the convenience of field process execution, the constant C is preferably 30mm, which has the advantages of ensuring that all corner cracks are cut off, avoiding excessive trimming and improving the yield.
Further, the tapping temperature of the casting blank is controlled to be 1180-1250 ℃, the casting blank is tapped and is immediately subjected to high-pressure dephosphorization, the surface temperature of the casting blank is controlled to be above 1050 ℃ when the casting blank arrives at a rolling mill, the surface temperature of the casting blank is controlled to be above 1020 ℃ in the rough rolling stage, the pass reduction rate is controlled to be within 20%, the rough rolling compression ratio is greater than 2.3, and the total extrusion edge amount of the vertical roll in the rough rolling stage is controlled to be within 30 mm.
Further, the thickness of the steel airing after rough rolling is controlled according to 1.5-2.1 times of the thickness of a finished product, the maximum thickness of the steel airing is not more than 130mm, the number of the steel airing blocks and the rolling blocks to be heated are controlled within 4, and the steel airing time is not more than 8 minutes.
Preferably, for a steel plate with the airing thickness of more than or equal to 100mm, cooling a casting blank by adopting IC or ACC, wherein the cooling speed is controlled to be below 10 ℃/s; airing the steel plate with the thickness less than 100mm, and cooling the casting blank without using IC or ACC.
The purpose of controlling the steel airing time is to control the steel airing thickness to be too thick in the two-stage rolling process, so that the steel airing time is too long under the natural cooling condition, the steel airing time is too long, austenite crystal grains are too large due to the too long steel airing time, and meanwhile, precipitates such as AlN are separated out along the austenite crystal boundaries, so that the high-temperature plasticity of the steel plate is rapidly reduced; during the finish rolling, under the action of a large rolling force, cracks can extend and propagate along austenite grain boundaries, so that the width of the corner cracks is increased.
Furthermore, the initial rolling temperature in the finish rolling stage is not lower than 830 ℃, the final rolling temperature is not lower than 780 ℃, the rolling surface temperature in the whole finish rolling stage is not lower than 780 ℃, except that high-pressure water is used for cooling in the first and last passes, high-pressure water is forbidden to be used in the rest passes, and the reduction rate of the finish rolling pass is controlled within 25%.
The beneficial effects of the invention include:
this patent judge the formula not only can be used to judge whether continuous casting billet bight crackle needs the clearance, can be used to continuous casting billet angle crackle rolling back steel sheet crack width estimation moreover for the optimization of rolling steel sheet side cut volume improves the yield.
The heating and rolling process control method can effectively control the problem of 'inward shift' of the corner crack rolling process of the continuous casting billet, and avoid the increase of the width of a crack strip in the steel plate rolling process. The width of the crack zone is increased mainly because of the flattening in the rolling process of the continuous casting billet and the flattening after bulging and edge squeezing. Generally, the lower the rolling temperature is, the larger the rolling friction coefficient is, the larger the rolling reduction is, and the more severe the flattening and bulging are; this patent is mainly through improving rolling temperature, control rough rolling, finish rolling compression ratio, restriction rolling reduction, reduces rolling coefficient of friction, suppresses to turn over flat and drum tripe broadly and opens up, realizes crackle "rebound" width control.
According to the scheme, the flattening and widening of the rolled medium plate of 40-100mm can be reduced to be below 30mm from the original maximum 60-80mm, the corner cracks of the continuous casting billet are free from cleaning rolled qualified products under the condition of lower trimming amount of the rolled steel plate, the rolling yield is improved, and the cleaning cost is reduced.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention are clearly and completely described below. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention, are within the scope of the invention.
The rolling method of the medium plate comprises the following steps of smelting molten iron, casting to obtain a continuous casting blank, heating, rolling and finishing the casting blank to obtain a finished steel plate, and specifically comprises the following steps:
the width of the casting blank is accurately controlled by the continuous casting machine, and the width error is controlled to be-5 to +10 mm.
After the continuous casting billet is produced, the continuous casting process and the components are normal, one casting billet is selected and inspected every 3 furnaces, and the component change and process fluctuation heat are selected and inspected 1 according to 1 furnace, and the width of a corner crack strip and the width of the casting billet are measured; the actual width B of the casting blank must be accurately measured when the casting blank is sampled and inspected0And width B of corner cracks on both sides of the casting blank1、B2. The width of the corner crack of the casting blank is calculated according to the maximum width of the crack from the edge of the casting blank, the two sides of the corner crack are respectively measured and are accurate to mm, and the accuracy and reliability of measured data are guaranteed.
Whether the casting blank is cleaned or not is determined according to the width of the crack strip of the casting blank and the rolling width-to-width ratio, and a formula for specifically judging whether the casting blank is cleaned or not is as follows:
ΔB＞（B1+B2）*B/B0+C
and judging whether to clean or not according to the sampling inspection condition of the corner cracks of the casting blank, wherein the casting blank meeting the requirement of the judgment formula can be directly charged without cleaning.
The tapping temperature of the casting blank is controlled to be 1180-1250 ℃, the casting blank is tapped and immediately subjected to high-pressure dephosphorization, the casting blank is strictly forbidden to stay for a long time after dephosphorization, the surface temperature of the casting blank is controlled to be above 1050 ℃ when the casting blank reaches a rolling mill, and the surface temperature of the casting blank is controlled to be above 1020 ℃ in the rough rolling stage.
The measured actual width of the casting blank is synchronized to an automatic rolling system before the rough rolling of the casting blank, the measured actual width of the casting blank is used for calculating the thickness of the steel to be rolled of a reduction regulation, the single-pass reduction rate in the rough rolling stage is controlled within 20% and used for accurately controlling the width to be widened, and the total extrusion edge of a vertical roller in the rough rolling stage is controlled within 30mm, so that excessive extrusion edge is avoided.
The steel airing thickness is controlled according to 1.5-2.1 times of the thickness of a finished product, the steel airing thickness is prevented from being too thick, the maximum steel airing thickness is not more than 130mm, the number of steel airing blocks and steel waiting rolling blocks is controlled within 4, and the steel airing time is not more than 8 minutes. If the steel plate with the steel airing thickness being more than or equal to 100mm is aired, cooling the casting blank by adopting IC or ACC, controlling the cooling speed to be below 10 ℃/s, and ensuring that the finish rolling temperature meets the process requirement; and airing the steel plate with the thickness of less than 100mm, so that the casting blank does not need to be cooled by IC or ACC.
And in the finish rolling stage, the use of high-pressure water and roll body water is controlled, and the use of high-pressure water is forbidden in other passes except the head and tail passes of finish rolling, so that the over-high temperature reduction of the steel plate is avoided. Particularly, the temperature of the edge of the steel plate is well controlled, and the rolling temperature of the edge of the steel plate is strictly prevented from being too low.
The initial rolling temperature in the finish rolling stage is not lower than 830 ℃, the finish rolling temperature is not lower than 780 ℃, the surface temperature of the steel plate in the whole finish rolling stage is not lower than 780 ℃, and the rolling reduction rate of the finish rolling pass is controlled within 25%.
Example 1
The method is characterized in that a 45mm thick steel plate is planned to be rolled in batches by a 300mm section continuous casting blank, the width of a single corner crack of the casting blank is below 25mm, the aspect ratio of the rolled steel plate is 1.2, according to the formula of the patent, the width of the crack strip is (25 + 25) multiplied by 1.2+30=90mm, and the rolled material lifting trimming amount is required to be cut off only by being larger than 90mm, so that the 100mm trimming amount of the rolled steel plate can be designed, and the cleaning-free rolling of the casting blank is realized.
The tapping temperature of the casting blank is controlled to be 1200-1240 ℃, the high-pressure dephosphorization is carried out immediately after the casting blank is tapped, the long-time residence is strictly forbidden after the dephosphorization, the surface temperature of the casting blank is higher than 1080 ℃ when the casting blank reaches a rolling mill, and the surface temperature of the casting blank is kept above 1020 ℃ in the rough rolling stage.
The measured actual width of the casting blank is synchronized to an automatic rolling system before the rough rolling of the casting blank, the measured actual width is used for calculating the thickness of the steel to be rolled of the reduction regulation, the single-pass reduction rate in the rough rolling stage is controlled to be 5-20% and used for accurately controlling the width to be widened, and the total extrusion edge of a vertical roller in the rough rolling stage is controlled to be below 30mm, so that excessive extrusion edge is avoided.
And after rough rolling is finished, the steel airing thickness is 90mm, the number of steel airing blocks and rolling blocks to be heated is controlled within 4, the steel airing time of each block is 5-8 minutes, and ACC cooling is not performed any more.
And in the finish rolling stage, the use of high-pressure water and roll body water is controlled, and the use of high-pressure water is forbidden in other passes except the head and tail passes of finish rolling, so that the over-high temperature reduction of the steel plate is avoided. Particularly, the temperature of the edge of the steel plate is well controlled, and the rolling temperature of the edge of the steel plate is strictly prevented from being too low.
The initial rolling temperature of the finish rolling stage is 840-860 ℃, the finish rolling temperature is above 800 ℃, the surface temperature of the steel plate is not lower than 780 ℃ in the whole finish rolling stage, and the rolling reduction rate of the finish rolling pass is controlled to be 10-25%.
After the steel plate is straightened, the width of the crack at the unilateral edge part is about 40-45mm, the design of the trimming amount of 100mm is met, the yield of the steel plate is improved by 0.8%, and the corner cleaning cost of a continuous casting blank is saved.
Example 2
The method is characterized in that a 70mm thick steel plate is planned to be rolled in batches by a continuous casting blank with a 350mm section, the unilateral crack width of the casting blank is less than 20mm, the spread width ratio of the rolled steel plate is 1.4, the width of the crack strip is (20 + 20) × 1.4+30=86mm according to the formula of the patent, and the crack can be cut off only when the rolling material lifting trimming amount is larger than 86mm, so that the 90mm trimming amount of the rolled steel plate can be designed, and the cleaning-free rolling of the casting blank is realized.
The tapping temperature of the casting blank is controlled to be 1200-1240 ℃, the high-pressure dephosphorization is carried out immediately after the casting blank is tapped, the long-time residence is strictly forbidden after the dephosphorization, the surface temperature of the casting blank is higher than 1080 ℃ when the casting blank reaches a rolling mill, and the surface temperature of the casting blank is more than 1020 ℃ in the rough rolling stage.
Before rough rolling of the casting blank, the measured actual width of the casting blank is synchronized to an automatic rolling system for calculating the thickness of the steel to be rolled of the reduction regulation, the single-pass reduction rate in the rough rolling stage is controlled to be 5-20% and used for accurately controlling the width to be widened, and the rough rolling stage is carried out; the total extrusion edge amount of the vertical roller is controlled to be below 30mm, so that excessive extrusion edge is avoided.
And when the rough rolling is finished, the steel airing thickness is 130mm, the steel airing and the number of rolling blocks to be heated are controlled within 4, the steel airing time of each block is 5-8 minutes, the casting blank is cooled by adopting IC or ACC, the cooling speed is controlled at 5-10 ℃/s, the final cooling temperature is 800 plus one year, and the process requirement of the rolling temperature in the finish rolling stage is met after the steel is fully re-red.
And in the finish rolling stage, the use of high-pressure water and roll body water is controlled, and the use of high-pressure water is forbidden in other passes except the head and tail passes of finish rolling, so that the uneven cooling and the too low temperature of the steel plate are avoided. Particularly, the temperature of the edge of the steel plate is well controlled, and the rolling temperature of the edge of the steel plate is strictly prevented from being too low.
The initial rolling temperature of the finish rolling stage is 830-840 ℃, the finish rolling temperature is higher than 790 ℃, the surface temperature of the steel plate is not lower than 780 ℃ in the whole finish rolling stage, and the rolling reduction rate of the finish rolling pass is controlled to be 10-20%.
After the steel plate is straightened, the width of the single-side edge crack is 40mm, the design of the single-side edge cutting amount of 45mm is met, the edge cutting amount is reduced from 120mm to 90mm, and the rolling yield of the steel plate is improved by about 1.2%.
Finally, the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting, and other modifications or equivalent substitutions made by the technical solutions of the present invention by those of ordinary skill in the art should be covered within the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solutions of the present invention.
Claims (7)
1. A method for rolling a medium plate of 40-100mm in a manner of avoiding cleaning corner cracks of a continuous casting blank and reducing trimming cut comprises the steps of smelting molten iron and casting to obtain the continuous casting blank, and heating, rolling and finishing the casting blank to obtain a finished steel plate0And width B of corner cracks on both sides of the casting blank1、B2Carrying out measurement; if only continuous casting blank corner cracks exist, whether the casting blank needs to be cleaned or not can be determined according to the width of a casting blank crack strip and the rolling width-to-width ratio, and the specific judgment formula is as follows:
ΔB＞（B1+B2）*B/B0+C
delta B is the total trimming amount of two edges of the rolled steel plate by lifting material, B0Is the width of the cast slab, B1、B2The widths of cracks at the left corner and the right corner of a casting blank are respectively, B is the rolling width of a steel plate, and C is a constant;
the cracks at the corners of the continuous casting billet meet the requirements of the judging formula, and the continuous casting billet can be directly charged and rolled without being cleaned.
2. The method for rolling the medium plate of 40-100mm with the corner cracks free from cleaning and the low trimming cut amount of the continuous casting billet as claimed in claim 1, wherein the constant C is between 10mm and 40 mm.
3. The method for rolling the medium plate of 40-100mm with the corner cracks free from cleaning and the low trimming cut amount of the continuous casting billet as claimed in claim 2, wherein the constant C is 30 mm.
4. The method for rolling the medium plate with the thickness of 40-100mm by the aid of the continuous casting blank corner crack cleaning-free low trimming cut amount as claimed in claim 1, wherein the tapping temperature of the casting blank is controlled to be 1180-1250 ℃, the casting blank is immediately subjected to high-pressure phosphorus removal after being tapped, the surface temperature of the casting blank is controlled to be above 1050 ℃ when the casting blank is fed into a rolling mill, the surface temperature of the casting blank is controlled to be above 1020 ℃ in a rough rolling stage, the reduction rate of the rough rolling pass is controlled to be within 20%, the rough rolling compression ratio is greater than 2.3, and the total edge extrusion amount of the vertical roll in the rough rolling stage is controlled to be within 30 mm.
5. The method for rolling the medium plate with the thickness of 40-100mm by the continuous casting billet corner crack cleaning-free low trimming amount according to claim 1, wherein the steel airing thickness after the rough rolling is controlled according to the thickness of a finished product by 1.5-2.1 times, the maximum steel airing thickness is not more than 130mm, the number of steel airing blocks and rolling blocks to be heated is controlled within 4, and the steel airing time is not more than 8 minutes.
6. The method for rolling the medium plate with the thickness of 40-100mm by the continuous casting billet corner crack cleaning-free low trimming cut amount according to claim 3, characterized in that for the intermediate billet with the airing thickness of more than or equal to 100mm, the casting billet is cooled by IC or ACC, and the cooling speed is controlled below 10 ℃/s; and airing the intermediate blank with the steel thickness of less than 100mm, and cooling the casting blank without using IC or ACC.
7. The method for rolling the medium plate with the thickness of 40-100mm by the aid of the continuously cast slab corner cracks without cleaning and the low trimming cut amount according to claim 1, wherein the initial rolling temperature in a finish rolling stage is not lower than 830 ℃, the final rolling temperature is not lower than 780 ℃, the rolling surface temperature in the whole finish rolling stage is not lower than 780 ℃, high-pressure water is forbidden to be used in other passes except for the cooling by the high-pressure water in the head-and-tail high-pressure phosphorus removal pass, and the reduction rate of the finish rolling pass is controlled within 25%.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010444648.3A CN113695396B (en) | 2020-05-23 | 2020-05-23 | Method for rolling 40-70mm medium plate by using continuous casting billet corner cracks without cleaning and with low trimming cut amount |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010444648.3A CN113695396B (en) | 2020-05-23 | 2020-05-23 | Method for rolling 40-70mm medium plate by using continuous casting billet corner cracks without cleaning and with low trimming cut amount |
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| CN113695396A true CN113695396A (en) | 2021-11-26 |
| CN113695396B CN113695396B (en) | 2023-03-21 |
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|---|---|---|---|---|
| JPS58192659A (en) * | 1982-05-04 | 1983-11-10 | Kawasaki Steel Corp | Continuous casting device of hollow steel billet |
| EP0662358A1 (en) * | 1994-01-10 | 1995-07-12 | Tippins Incorporated | Method and apparatus for intermediate thickness slab caster and inline hot strip and plate line |
| CN102080184A (en) * | 2010-12-21 | 2011-06-01 | 南阳汉冶特钢有限公司 | 75-mm Z15 series steel plate prepared by rolling 250-mm casting blank and production method of 75-mm Z15 series steel plate |
| CN102284482A (en) * | 2011-06-21 | 2011-12-21 | 秦皇岛首秦金属材料有限公司 | Method for effectively controlling horizontal-edge crack of medium-thickness plate |
| CN102409221A (en) * | 2011-12-02 | 2012-04-11 | 武汉钢铁(集团)公司 | Method for controlling edge cracks of peritectic steel containing niobium or boron |
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| CN103752622A (en) * | 2013-12-23 | 2014-04-30 | 宝山钢铁股份有限公司 | Heavy plate rolling control method for removing defect on edge of continuous casting bloom |
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| CN102653835A (en) * | 2012-05-09 | 2012-09-05 | 东北大学 | Method for reducing transverse cracks at corner of continuous casting billet of boron-steel-containing wide-thick plate |
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