CN113249558A - Method for reducing coarse grain defects of low-carbon aluminum-killed steel and low-carbon aluminum-killed steel prepared by same - Google Patents
Method for reducing coarse grain defects of low-carbon aluminum-killed steel and low-carbon aluminum-killed steel prepared by same Download PDFInfo
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- CN113249558A CN113249558A CN202110405105.5A CN202110405105A CN113249558A CN 113249558 A CN113249558 A CN 113249558A CN 202110405105 A CN202110405105 A CN 202110405105A CN 113249558 A CN113249558 A CN 113249558A
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0226—Hot rolling
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0236—Cold rolling
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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Abstract
The embodiment of the invention discloses a method for reducing coarse grain defects of low-carbon aluminum killed steel and the prepared low-carbon aluminum killed steel, which comprises the following steps: smelting and continuously casting the molten steel to obtain a casting blank of low-carbon aluminum killed steel; in the continuous casting, the section of a casting blank is less than or equal to 1250mm, and the casting blank pulling speed is 1.4-2 m/min; the section of the casting blank is more than 1250mm, and the casting blank pulling speed is 1.2-1.6 m/min; heating the casting blank before rolling, rough rolling, finish rolling, cooling after rolling to obtain a finish rolled plate; the heating temperature before rolling is 1160-1180 ℃, the heat preservation time is 180-200 min, and the air coefficient is controlled to be 1.05-1.1; and coiling the finish rolling plate to obtain a hot rolling coil, then cooling the hot rolling coil to less than 400 ℃ by water, and then cold rolling and annealing to obtain the low-carbon aluminum killed steel with improved coarse crystal defects. The invention reduces the coarse grain defect of the low-carbon aluminum killed steel by controlling the parameters of continuous casting, heating before rolling and cooling after coiling.
Description
Technical Field
The invention relates to the technical field of ferrous metallurgy, in particular to a method for reducing coarse grain defects of low-carbon aluminum killed steel and the low-carbon aluminum killed steel prepared by the method.
Background
The low-carbon aluminum killed steel is low in cost, and good in punching forming performance, is a steel grade widely applied in the industries of automobiles and household appliances, in recent years, along with the steel productivity process, customers have more and more strict requirements on the surface quality of products, the surface of the low-carbon steel after hot continuous rolling has coarse crystal defects, microscopic appearance is that local crystal grains are thick, as shown in figure 1, meanwhile, the color of the surface of the strip steel at the coarse crystal position is dark, the strip steel is finally inherited to a finished product, the use of downstream customers is influenced, the attractiveness is influenced, the punching phenomena of surface wrinkling and the like can also occur, so that the unqualified products of the customers are increased, and the loss is caused to the customers.
The production process of the low-carbon aluminum killed steel relates to a plurality of procedures such as steel making, continuous casting, rolling and the like, the defects of the shallow surface layer at the upstream are strongly inherited to the defects at the downstream, and the control of the surface coarse-grain defects is a relatively complex problem because each procedure goes through a high-temperature stage and the surface layer position is accompanied with high-temperature oxidation.
Therefore, how to develop a method for reducing the coarse grain defect of the low-carbon aluminum killed steel becomes a technical problem to be solved urgently.
Disclosure of Invention
The invention aims to provide a method for reducing coarse grain defects of low-carbon aluminum killed steel and the prepared low-carbon aluminum killed steel, and the coarse grain defects of the surface of a low-carbon aluminum killed steel pickled plate are reduced.
In order to achieve the above object, the present invention provides a method for reducing coarse grain defects of low carbon aluminum killed steel, the method comprising:
smelting and continuously casting the molten steel to obtain a casting blank of low-carbon aluminum killed steel; in the continuous casting, when the section of a casting blank is less than or equal to 1250mm, the casting blank pulling speed is controlled to be 1.4-2 m/min; when the section of the casting blank is larger than 1250mm, controlling the casting blank pulling speed to be 1.2-1.6 m/min; the mass fraction of Mn in the casting blank is 0.2-0.4%;
heating the casting blank before rolling, rough rolling, finish rolling and cooling after rolling to obtain a finish rolled plate; wherein the temperature of the heating before rolling is 1160-1180 ℃, the heat preservation time is 180-200 min, and the air coefficient of the heating before rolling is controlled to be 1.05-1.1;
and coiling the finish rolling plate to obtain a hot rolling coil, then cooling the hot rolling coil to less than 400 ℃ by water, and then cold rolling and annealing to obtain the low-carbon aluminum killed steel with improved coarse crystal defects.
Further, the chemical components of the steel are as follows in mass fraction: c: 0.02 to 0.04%, Mn: 0.2-0.4%, Si is less than or equal to 0.03%, Alt: 0.03-0.05%, and the balance of Fe and inevitable impurities.
Further, in the rough rolling, 3+3 passes are adopted for rolling, the rolling speed is controlled to be 2-5 m/s, the total deformation of the rough rolling is controlled to be 75-85%, and the inlet temperature of the rough rolling is controlled to be 1140-1170 ℃.
Further, in the precision rolling, 6 passes of rolling are adopted, the rolling speed is controlled to be 8-12 mm/s, the total deformation of the precision rolling is controlled to be 85-95%, the inlet temperature of the precision rolling is controlled to be 1000-1040 ℃, and the final temperature of the precision rolling is controlled to be 900-920 ℃.
Further, the post-rolling cooling comprises: cooling to 500-530 ℃ at a rate of 30-50 ℃/s.
Further, the coiling temperature is 700-750 ℃.
Further, the water cooling of the hot rolled coil to < 400 ℃, specifically comprises:
and forcibly cooling the hot rolled coil in circulating water for more than or equal to 30min to be cooled to less than 400 ℃.
Further, in the cold rolling, the cold rolling reduction is controlled to be 60-95%.
The invention also provides the low-carbon aluminum killed steel prepared by the method.
One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:
the invention provides a method for reducing coarse grain defects of low-carbon aluminum killed steel, which comprises the following steps: smelting and continuously casting the molten steel to obtain a casting blank of low-carbon aluminum killed steel; in the continuous casting, when the section of a casting blank is less than or equal to 1250mm, the casting blank pulling speed is controlled to be 1.4-2 m/min; when the section of the casting blank is larger than 1250mm, controlling the casting blank pulling speed to be 1.2-1.6 m/min; the mass fraction of Mn in the casting blank is 0.2-0.4%; heating the casting blank before rolling, rough rolling, finish rolling and cooling after rolling to obtain a finish rolled plate; wherein the temperature of the heating before rolling is 1160-1180 ℃, the heat preservation time is 180-200 min, and the air coefficient of the heating before rolling is controlled to be 1.05-1.1; and coiling the finish rolling plate to obtain a hot rolling coil, then cooling the hot rolling coil to less than 400 ℃ by water, and then cold rolling and annealing to obtain the low-carbon aluminum killed steel with improved coarse crystal defects. According to the embodiment of the invention, the problem of coarse grain defects of the low-carbon aluminum killed steel can be easily reduced under the condition of not increasing equipment by controlling the parameters of continuous casting, heating before rolling and cooling after coiling, and the surface quality of the low-carbon aluminum killed steel is improved; the method is simple, economical and efficient.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
FIG. 1 is a coarse grain defect morphology of a prior art medium low carbon aluminum killed steel;
FIG. 2 shows the coarse grain morphology of the hot-rolled surface when Mn in the steel blank composition of comparative example 1 is 0.45%;
FIG. 3 shows the coarse grain morphology of the hot-rolled surface when Mn in the steel blank composition is 0.25% in example 1;
FIG. 4 shows the coarse grain morphology on the hot-rolled surface of a casting blank of comparative example 2 with a cross section of 1300mm and a casting speed of 2.0 m/min;
FIG. 5 shows the coarse grain morphology on the surface of a hot coil in the case of a casting blank with a cross section of 1300mm and a casting speed of 1.4m/min in example 1 of the present invention;
FIG. 6 shows the coarse-grained morphology of the surface of the hot coil in comparative example 3 at a heating temperature of 1210 ℃ for a heating time of 210 min;
FIG. 7 shows the coarse-grained morphology of the surface of the hot-rolled steel sheet at 1170 ℃ for 180min in example 1 of the present invention;
FIG. 8 shows the morphology of coarse grains on the surface of a hot coil in example 1 of the present invention with forced water cooling;
FIG. 9 shows the coarse grain morphology of the surface of the hot coil in comparative example 4, which is cooled by air;
FIG. 10 is a flowchart of a method for reducing coarse grain defects in a low carbon aluminum killed steel according to an embodiment of the present invention.
Detailed Description
The present invention will be described in detail below with reference to specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly apparent therefrom. It will be understood by those skilled in the art that these specific embodiments and examples are for the purpose of illustrating the invention and are not to be construed as limiting the invention.
Throughout the specification, unless otherwise specifically noted, terms used herein should be understood as having meanings as commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. If there is a conflict, the present specification will control.
Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.
According to an exemplary embodiment of the present invention, a method for reducing coarse grain defects of a low carbon aluminum killed steel is provided, as shown in fig. 10, including:
s1, smelting and continuously casting the molten steel to obtain a casting blank of low-carbon aluminum killed steel; in the continuous casting, when the section of a casting blank is less than or equal to 1250mm, the casting blank pulling speed is controlled to be 1.4-2 m/min; when the section of the casting blank is larger than 1250mm, controlling the casting blank pulling speed to be 1.2-1.6 m/min;
as one of optional embodiments, the steel comprises the following chemical components in percentage by mass: c: 0.02 to 0.04%, Mn: 0.2-0.4%, Si is less than or equal to 0.03%, Alt: 0.03-0.05%, and the balance of Fe and inevitable impurities. The chemical composition of the steel controls the content of Mn element to be 0.2-0.4% so as to reduce the coarse grain defect, the excessive Mn element easily causes the coarse grain defect, and the insufficient Mn element is not beneficial to increasing the strength and hardness of the steel. The content control of other components is the same as that of the prior art.
S2, heating the casting blank before rolling, roughly rolling, finely rolling, cooling after rolling to obtain a finely rolled plate; wherein the temperature of the heating before rolling is 1160-1180 ℃, the heat preservation time is 180-200 min, and the air coefficient of the heating before rolling is controlled to be 1.05-1.1;
in an optional embodiment, in the rough rolling, 3+3 passes are adopted for rolling, the rolling speed is controlled to be 2-5 m/s, the total deformation of the rough rolling is controlled to be 75-85%, and the inlet temperature of the rough rolling is controlled to be 1140-1170 ℃. The arrangement is favorable for controlling the temperature drop in the rough rolling process and ensuring the uniformity of the hot coil head and tail structure performance.
In an optional embodiment, in the fine rolling, 6 passes of rolling are adopted, the rolling speed is controlled to be 8-2 mm/s, and the total deformation amount of the fine rolling is controlled to be 85-95%. The arrangement is favorable for controlling the temperature drop in the finish rolling process and ensuring the uniformity of the hot coil head and tail structure performance.
As an alternative embodiment, the post-rolling cooling comprises: and cooling to 500-530 ℃ at the speed of 30-50 ℃/s by adopting an ultra-fast cooling process front end cooling mode. Too low a cooling rate adversely affects the increase in the strength of the structure, and too high a cooling rate adversely affects the appearance of an excessively hard structure phase.
S3, coiling the finish rolling plate to obtain a hot rolling coil, then cooling the hot rolling coil to be less than 400 ℃, and then cold rolling and annealing to obtain the low-carbon aluminum killed steel with improved coarse grain defects.
In an optional embodiment, the coiling temperature is 700 to 750 ℃. The coiling temperature is too low to be beneficial to the coiling effect; the coiling temperature is too high, the phase transition temperature is too low, and the growth of crystal grains is easy to occur in the process of slowly cooling the hot-rolled coil storage to 400 ℃, so that the generation of coarse crystal defects is induced;
as an alternative embodiment, the water-cooling the hot-rolled coil to < 400 ℃, specifically includes:
and forcibly cooling the hot rolled coil in circulating water for more than or equal to 30min to be cooled to less than 400 ℃. The water cooling effect is good, the air cooling rate is slow, the temperature can be reduced to 400 ℃ only after the cooling in the air is put through for at least 4 hours, the crystal grain growth can be well inhibited through the water cooling, and the occurrence of coarse crystal defects is reduced.
In an optional embodiment, in the cold rolling, a cold rolling reduction is controlled to be 60 to 95%. This is advantageous in that a lower annealing temperature in the subsequent annealing process can achieve a suitable grain size.
From the above, it can be seen that the general idea of the method for reducing the coarse grain defect of the low-carbon aluminum killed steel provided by the embodiment of the invention is as follows:
influence of Mn element on crystal grain:
the application finds that: alloy element components in the steel billet have great influence on surface coarse grains in the final rolling process, when Mn elements in steel are more, Mn elements are segregated in the molten steel solidification process, Mn in segregation is retained in a casting blank to form a Mn-rich zone and a Mn-poor zone, and in the subsequent casting blank heating rolling process, the Mn-rich zone and the Mn-poor zone existing in the original structure promote C elements to form banded segregation, the steel billet occurs in the center of the strip steel to form a banded structure, and the steel billet occurs in the surface layer of the strip steel to form white and bright zone coarse grain defects. The content of Mn element is controlled to be 0.2-0.4%, so that the coarse crystal defect can be reduced, the coarse crystal defect is easily caused by too much Mn element, and the strength and hardness of the steel are not increased by too little Mn element.
Secondly, the influence on the crystal grains in the continuous casting process:
the application finds that: in the steelmaking continuous casting process, the generation of slag rolling defects on the surface of a casting blank can be caused by the reasons of overlarge liquid level fluctuation of a crystallizer, unstable molten steel flow velocity, poor melting state of casting powder and the like, the positions of the slag rolling defects are easy to form oxidation channels when a subsequent heating furnace is heated, oxidation and decarburization are caused, further exposure and oxidation are carried out in the subsequent hot rolling high-temperature rolling process, coarse crystal defects can be formed on a shallow surface layer, and the occurrence of the above poor states such as liquid level fluctuation can be reduced by controlling the drawing speed in the continuous casting process. The section of the casting blank is not more than 1250mm, and the casting speed is not less than 1.4m/min and not more than 2.0 m/min; the section of the casting blank is larger than 1250mm, and the pulling speed is more than or equal to 1.2m/min and less than or equal to 1.6m/min, so as to prevent the slag entrapment of the crystallizer caused by improper control of the pulling speed.
When the section of the casting blank is less than or equal to 1250mm, slag entrapment of the crystallizer is easily caused if the casting blank pulling speed is less than 1.4m/min or more than 2 m/min; when the section of the casting blank is more than 1250mm, if the casting blank pulling speed is less than 1.2m/min or more than 1.6m/min, slag entrapment of the crystallizer is easily caused;
thirdly, the heating process before rolling influences the surface quality:
the application finds that: the hot rolling process research finds that the heating temperature and the heat preservation time of the heating furnace and the atmosphere of the heating furnace have great influence on surface decarburization and final surface coarse grains, the heating temperature has a decarburization peak value, and when the heating temperature is 1180-1240 ℃, and the heat preservation time exceeds 200min, the surface decarburization is serious; the heating temperature before rolling is 1160-1180 ℃, and the heat preservation time is 180-200 min, so that the decarburization is the slightest; meanwhile, the decarburization of the heating furnace is the slightest in the weak oxidation atmosphere, and the air coefficient of the heating furnace is controlled to be 1.05-1.10.
Influence of hot coil cooling process on surface quality
The application finds that: in order to meet the production requirement of a subsequent cold rolling continuous annealing production line, the coiling temperature of low-carbon aluminum killed steel is generally 700-750 ℃, the coiling temperature is too high, the phase change temperature is too low, the growth of crystal grains is easy to occur in the process of slowly cooling a hot rolling coil warehouse to 400 ℃, and the generation of coarse crystal defects is induced.
According to another exemplary embodiment of the invention, the low-carbon aluminum killed steel and pickled plate with the improved surface coarse crystal defects, which is prepared by the method, is provided.
The method for reducing the coarse grain defects of the low carbon aluminum killed steel of the present application will be described in detail with reference to examples, comparative examples and experimental data.
S1, smelting the molten iron by a converter, and obtaining a casting blank of the low-carbon aluminum killed steel by adopting a continuous casting mode; the actual chemical composition is shown in table 1.
TABLE 1 Low carbon aluminum killed steel chemical composition (wt%)
S2, heating the casting blank before rolling, roughly rolling, finely rolling, cooling after rolling to obtain a finely rolled plate; wherein in the rough rolling, 3+3 passes are adopted for rolling, the rolling speed is controlled to be 2-5 m/s, the total deformation of the rough rolling is controlled to be 75-85%, and the inlet temperature of the rough rolling is controlled to be 1140-1170 ℃. In the precision rolling, 6 passes are adopted for rolling, the rolling speed is controlled to be 8-12 mm/s, the total deformation of the precision rolling is controlled to be 85-95%, the inlet temperature of the precision rolling is controlled to be 1000-1040 ℃, and the final temperature of the precision rolling is controlled to be 900-920 ℃. The post-rolling cooling comprises: cooling to 500-530 ℃ at a rate of 30-50 ℃/s. The coiling temperature is 700-750 ℃.
Other parameters for each example and each comparative example are specifically shown in table 2.
TABLE 2 Process parameters
S3, coiling the finish rolled plate at 700-750 ℃ to obtain a hot rolled coil; and then cooling the hot rolled coil to less than 400 ℃, and then cold rolling and annealing to obtain the low-carbon aluminum killed steel pickled plate with the improved surface coarse crystal defects.
The reticulate pattern proportion of the surface of the low-carbon aluminum killed steel pickled plate of each group is counted, and the result is shown in table 3.
TABLE 3
From the data in table 3, it can be seen that:
in comparative example 1, Mn is 0.45%, which is greater than the range of 0.2 to 0.4% in the inventive example, and a surface coarse crystal defect is present and the ratio is high;
in the comparative example 2, the casting blank has a section of 1300mm, the pulling speed is 2.0m/min and is greater than the range of 1.2-1.6 m/min in the embodiment of the invention, and the casting blank has surface coarse crystal defects and high proportion;
in the comparative example 3, the heating temperature is 1210 ℃, the heating time is 210min, the heating temperature is 1160-1180 ℃ higher than the heating temperature before rolling in the embodiment of the invention, the heat preservation time is 180-200 min, the surface coarse crystal defect exists, and the proportion is high;
in comparative example 4, air cooling was used for cooling after hot rolling of the coil, and the defect of coarse grains on the surface was present and the ratio was high;
the problems of coarse grain defects are avoided in examples 1 to 3, and the surface quality of the low-carbon aluminum killed steel is good.
FIGS. 2-9 illustrate:
as can be seen from FIGS. 2 to 3, by comparing example 1 with comparative example 1, the coarse grains on the surface of the hot coil are reduced with the reduction of the Mn element, which indicates that the coarse grains on the surface of the hot coil can be reduced to some extent by controlling the Mn element.
As can be seen from FIGS. 4-5, under the condition that the Mn content of the steel billet is less than 0.4% and the section of the casting blank is 1300mm, the casting speed of 2.0m/min is selected in comparative example 1 and 1.4m/min is selected in example 1, and the comparison shows that the severity of surface coarse grains can be reduced by reducing the casting speed.
As can be seen from FIGS. 6-7, under the same conditions that the Mn content of the steel billet is less than 0.4% and other processes are the same, the heating temperature of 1210 ℃ and the heating time of 210min are selected in the example 1; and the comparative example 3 adopts the heating temperature of 1170 ℃ and the heating time of 180min, and the comparison shows that the coarse crystal defect on the surface of the coil can be further alleviated by avoiding the peak value of the heating temperature and reducing the heating time.
From fig. 8-9, under the same conditions that the Nb + Ti content of the steel slab is less than 0.04%, the hot coil cooling process selected in example 1 is as follows: forcibly cooling in circulating water after the coil is subjected to hot rolling, coiling and off-line, and ensuring that the steel coil is cooled to below 400 ℃ in 30 minutes; the hot coil cooling process selected in comparative example 4 was: and cooling in the air after rolling, coiling and coil off-line, wherein the cooling speed after hot coiling and coil off-line is controlled by comparison, and better surface quality can be obtained by adopting a forced cooling process.
Finally, it should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (9)
1. A method of reducing coarse grain defects in low carbon aluminum killed steel, the method comprising:
smelting and continuously casting the molten steel to obtain a casting blank of low-carbon aluminum killed steel; in the continuous casting, when the section of a casting blank is less than or equal to 1250mm, the casting blank pulling speed is controlled to be 1.4-2 m/min; when the section of the casting blank is larger than 1250mm, controlling the casting blank pulling speed to be 1.2-1.6 m/min; the mass fraction of Mn in the casting blank is 0.2-0.4%;
heating the casting blank before rolling, rough rolling, finish rolling and cooling after rolling to obtain a finish rolled plate; wherein in the heating before rolling, the heating temperature is 1160-1180 ℃, the heat preservation time is 180-200 min, and the air coefficient is controlled to be 1.05-1.1;
and coiling the finish rolling plate to obtain a hot rolling coil, then cooling the hot rolling coil to less than 400 ℃ by water, and then cold rolling and annealing to obtain the low-carbon aluminum killed steel with improved coarse crystal defects.
2. The method for reducing the coarse grain defects of the low carbon aluminum killed steel as recited in claim 1, wherein the steel comprises the following chemical components in percentage by mass: c: 0.02 to 0.04%, Mn: 0.2-0.4%, Si is less than or equal to 0.03%, Alt: 0.03-0.05%, and the balance of Fe and inevitable impurities.
3. The method for reducing the coarse grain defects of the low carbon aluminum killed steel as claimed in claim 1, wherein the coarse rolling is performed by 3+3 passes, the rolling speed is controlled to be 2-5 m/s, the total deformation of the coarse rolling is controlled to be 75-85%, and the inlet temperature of the coarse rolling is controlled to be 1140-1170 ℃.
4. The method for reducing the coarse grain defects of the low-carbon aluminum killed steel as claimed in claim 1, wherein the rolling is performed in 6 passes in the fine rolling, the rolling speed is controlled to be 8-12 mm/s, the total deformation of the fine rolling is controlled to be 85-95%, the inlet temperature of the fine rolling is controlled to be 1000-1040 ℃, and the finish rolling temperature of the fine rolling is controlled to be 900-920 ℃.
5. The method of reducing macrocrystalline defects in a low carbon aluminum killed steel as described in claim 1, wherein said post-rolling cooling comprises: cooling to 500-530 ℃ at a rate of 30-50 ℃/s.
6. The method for reducing the coarse grain defects of the low carbon aluminum killed steel as claimed in claim 1, wherein the coiling temperature is 700-750 ℃.
7. The method of reducing macrocrystalline defects in low carbon aluminum killed steel as claimed in claim 1, wherein said water cooling said hot rolled coil to < 400 ℃, specifically comprises:
and forcibly cooling the hot rolled coil in circulating water for more than or equal to 30min to be cooled to less than 400 ℃.
8. The method for reducing the coarse grain defects of the low carbon aluminum killed steel as claimed in claim 1, wherein in the cold rolling, the cold rolling reduction is controlled to be 60-95%.
9. A low carbon aluminum killed steel made by the method of any one of claims 1 to 8.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60155625A (en) * | 1984-01-25 | 1985-08-15 | Nippon Kokan Kk <Nkk> | Hot rolling method of dead soft steel for forming finer grain |
| CN101096034A (en) * | 2006-06-27 | 2008-01-02 | 鞍钢股份有限公司 | Production method of ultra-low-carbon steel for sedan car cortical plate |
| CN101967543A (en) * | 2010-11-12 | 2011-02-09 | 攀钢集团钢铁钒钛股份有限公司 | Hot rolling heating method for low-carbon aluminum killed steel casting blank |
| CN102719729A (en) * | 2012-06-18 | 2012-10-10 | 首钢总公司 | Automotive low-carbon aluminum-killed steel sheet and production method thereof |
| CN103459639A (en) * | 2011-03-29 | 2013-12-18 | 新日铁住金不锈钢株式会社 | Ferritic stainless steel sheet having excellent heat resistance and processability, and method for producing same |
| CN109252110A (en) * | 2018-11-06 | 2019-01-22 | 鞍钢股份有限公司 | A kind of automobile low-carbon hot-rolling acid-cleaning plate and preparation method thereof |
-
2021
- 2021-04-15 CN CN202110405105.5A patent/CN113249558B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60155625A (en) * | 1984-01-25 | 1985-08-15 | Nippon Kokan Kk <Nkk> | Hot rolling method of dead soft steel for forming finer grain |
| CN101096034A (en) * | 2006-06-27 | 2008-01-02 | 鞍钢股份有限公司 | Production method of ultra-low-carbon steel for sedan car cortical plate |
| CN101967543A (en) * | 2010-11-12 | 2011-02-09 | 攀钢集团钢铁钒钛股份有限公司 | Hot rolling heating method for low-carbon aluminum killed steel casting blank |
| CN103459639A (en) * | 2011-03-29 | 2013-12-18 | 新日铁住金不锈钢株式会社 | Ferritic stainless steel sheet having excellent heat resistance and processability, and method for producing same |
| CN102719729A (en) * | 2012-06-18 | 2012-10-10 | 首钢总公司 | Automotive low-carbon aluminum-killed steel sheet and production method thereof |
| CN109252110A (en) * | 2018-11-06 | 2019-01-22 | 鞍钢股份有限公司 | A kind of automobile low-carbon hot-rolling acid-cleaning plate and preparation method thereof |
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