CN114058946A

CN114058946A - Low-anisotropy high-strength high-elongation steel substrate, tin-plated plate and preparation method of tin-plated plate

Info

Publication number: CN114058946A
Application number: CN202111200694.XA
Authority: CN
Inventors: 方圆; 宋浩; 石云光; 吴志国; 徐海卫; 于孟; 鲍成人; 莫志英; 王振文; 周保欣; 孙超凡; 王雅晴; 刘伟; 胡娜; 李海旭
Original assignee: Shougang Group Co Ltd
Current assignee: Shougang Group Co Ltd
Priority date: 2021-10-14
Filing date: 2021-10-14
Publication date: 2022-02-18
Anticipated expiration: 2041-10-14
Also published as: CN114058946B

Abstract

The application relates to the technical field of steel preparation, in particular to a low-anisotropy high-strength high-elongation steel substrate, a tin-plated plate and a preparation method thereof, wherein the steel substrate comprises the following chemical components: c, Si, Mn, P, S, Als, N, and the balance of Fe and impurities; the method comprises the following steps: obtaining a casting blank containing the chemical components; carrying out hot rolling, acid rolling, continuous annealing and flattening on the casting blank in sequence to obtain a steel substrate; the tin-plated plate comprises a steel substrate and a tin-plated layer, wherein the tin-plated layer covers at least one surface of the steel substrate; the method comprises the following steps: carrying out tin plating on the steel substrate to obtain a tin plate; by controlling the C, Mn and N content in the chemical components of the tin plate, C, Mn and N are added as solid solution strengthening elements, and the content of Al is controlled to be low, so that ferrite is formed, fine dispersion in crystal is distributed as a main carbide structure and partial carbide structures distributed in grain boundaries are formed, the anisotropy is reduced, and the strength and the elongation of the tin plate are improved.

Description

Low-anisotropy high-strength high-elongation steel substrate, tin-plated plate and preparation method of tin-plated plate

Technical Field

The application relates to the technical field of steel preparation, in particular to a low-anisotropy high-strength high-elongation steel substrate, a tin-plated plate and a preparation method of the low-anisotropy high-strength high-elongation steel substrate.

Background

The tin plate is a cold-rolled low-carbon steel plate or steel strip with tin layers plated on two sides, which is obtained through electrotinning operation, but the tin plate is widely applied to the canning field of packaging industry at present, but along with the continuous reduction of the thickness of the can wall, a user puts higher requirements on the strength of the tin plate for preparing a packaging can, and because the forming of the can body and the can cover of the packaging can has requirements on the elongation of the tin plate, the elongation also needs to be improved along with the increase of the strength.

At present, according to the standard regulation of GB/T2520 and 2017 'Cold-rolled tin-plated Steel plate and Steel strip', the degree of temper of a one-time cold-rolled tin-plated plate product is T-1-T-5, the yield strength grade after corresponding longitudinal aging is 230 MPa-435 MPa, and the strength requirement is not met; although a secondary cold rolling method, namely annealing and then cold rolling is adopted in China, the reduction rate is 15% -40% generally, the strength is improved through work hardening, but the elongation is sharply reduced, and the anisotropy is improved. Therefore, how to increase the elongation rate under the premise of meeting the strength requirement is a technical problem which needs to be solved urgently at present.

Disclosure of Invention

The application provides a low-anisotropy high-strength high-elongation steel substrate, a tin plate and a preparation method thereof, and aims to solve the technical problem that the elongation rate cannot be improved on the premise of meeting the strength requirement in the prior art.

In a first aspect, the present application provides a low-anisotropy high-strength high-elongation steel substrate, wherein the chemical composition of the steel substrate comprises, in mass fraction: c: 0.06-0.08%, Si is less than or equal to 0.02%, Mn: 0.35-0.6%, P is less than or equal to 0.015%, S is less than or equal to 0.012%, Als: 0.005% -0.02%, N: 0.006-0.01 percent, and the balance of Fe and impurities.

Optionally, the metallographic structure of the tin plate includes, by volume fraction: ferrite: 97-99%, carbide: 1 to 3 percent.

Optionally, the grain size of the ferrite is 4.5 μm to 5.5 μm.

In a second aspect, the present application provides a method for producing a low anisotropy, high strength and high elongation steel substrate, the method comprising:

obtaining a casting blank containing the chemical components;

and carrying out hot rolling, acid rolling, continuous annealing and leveling on the casting blank in sequence to obtain a steel matrix.

Optionally, the hot rolling comprises reheating, finish rolling and coiling; the reheating temperature is 1190-1230 ℃, the finishing temperature is 880-920 ℃, and the coiling temperature is 530-570 ℃.

Optionally, the speed of the final rolling is 11 m/s-15 m/s.

Optionally, the continuous annealing includes a soaking section and a rapid cooling section, the temperature of the rapid cooling section is less than or equal to 250 ℃, the cooling rate of the rapid cooling section is 50K/s to 90K/s, and the temperature of the soaking section is 640 ℃ to 60 ℃.

Optionally, the reduction rate of the acid rolling is more than or equal to 87%.

Optionally, the flat elongation is 2% to 3%.

In a third aspect, the present application provides a low-anisotropy high-strength high-elongation tin-plated sheet comprising a steel substrate and a tin-plated layer covering at least one surface of the steel substrate;

the steel substrate comprises the steel substrate of the first aspect.

In a fourth aspect, the present application provides a method for preparing a low-anisotropy, high-strength and high-elongation tin plate, the method comprising: and carrying out tin plating on the steel substrate to obtain a tin-plated plate.

Compared with the prior art, the technical scheme provided by the embodiment of the application has the following advantages:

according to the low-anisotropy high-strength high-elongation tin plate and the preparation method thereof, C, Mn and N are added as solid solution strengthening elements by controlling the content of C, Mn and N in chemical components of the tin plate, the content of A1 is controlled to be low, the solid solution strengthening effect of the N element is fully exerted, fine crystalline ferrite is formed in the tin plate, fine dispersion in crystal is mainly distributed in the crystal, and a part of carbide structures are distributed in grain boundaries, so that anisotropy is reduced, and the strength and the elongation of the tin plate are improved.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following embodiments or the drawings used in the description of the prior art are briefly described, and it is obvious for those skilled in the art to obtain other drawings without any inventive exercise.

FIG. 1 is a schematic flow diagram of a method of producing a steel substrate provided in an embodiment of the present application;

fig. 2 is a schematic flow chart of a method for manufacturing a tin-plated plate according to an embodiment of the present disclosure;

fig. 3 is a schematic metallographic structure of a steel matrix provided in an embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In one embodiment of the present application, as shown in fig. 1, there is provided a low-anisotropy, high-strength and high-elongation steel substrate, wherein the chemical composition of the steel substrate comprises, in mass fraction: c: 0.06-0.08%, Si is less than or equal to 0.02%, Mn: 0.35-0.6%, P is less than or equal to 0.015%, S is less than or equal to 0.012%, Als: 0.005% -0.02%, N: 0.006-0.01 percent, and the balance of Fe and impurities.

In the application, the positive effect that the mass fraction of C is 0.06% -0.08% is that C is used as a relevant element of strength, and the element C with a proper mass fraction can provide enough strength for the tin-plated plate prepared from a steel substrate; when the mass fraction is too large, the adverse effect is that too high C element causes slab cracking, and when the mass fraction is too small, the adverse effect is that too low C element content causes insufficient strength of the slab.

The positive effect that Si is less than or equal to 0.02 percent is to improve the surface quality of a steel matrix; when the mass fraction is too large, the adverse effect is that too high Si increases the scale and affects the surface quality of the steel matrix.

The positive effect that the mass fraction of Mn is 0.35-0.6% is that Mn can be used as a solid solution strengthening element with C, N to form various solid solutions, thereby reducing the anisotropy of the tin plate prepared from the steel matrix and improving the strength and the elongation of the tin plate prepared from the steel matrix; when the value range of the mass fraction is too large, the adverse effect is that too high Mn element causes higher alloy cost, and when the value range of the mass fraction is too small, the adverse effect is that too low Mn element content causes insufficient generated solid solution, anisotropy cannot be effectively reduced, the strength of the tin-plated plate prepared from the steel matrix is insufficient, and the elongation of the tin-plated plate prepared from the steel matrix is influenced.

The positive effect that P is less than or equal to 0.015 percent is to avoid plasticity reduction; when the mass fraction is too large, an adverse effect is caused in that too high a P content increases cold workability brittleness.

The positive effects that S is less than or equal to 0.012 percent are that the plasticity of a steel matrix is prevented from being reduced, and the generation of MnS inclusions is reduced; when the value range of the mass fraction is too large, the adverse effect is that the plasticity of a steel matrix is reduced, MnS inclusions are increased, and the performance of the steel matrix is influenced.

The positive effect that the mass fraction of the Als is 0.005-0.02% is that Al can form fine-grain carbide, so that the anisotropy of the tin plate prepared from the steel matrix can be reduced, and the strength of the tin plate prepared from the steel matrix is improved; when the range of the mass fraction is too large, an adverse effect will be caused in that too much A1 will form too much AIN solid solution, resulting in precipitation of A1N solid solution, while precipitation of A1N solid solution will cause surface defects in a tin plate produced from a steel substrate, and when the range of the mass fraction is too small, an adverse effect will be caused in that too low Al will not form sufficient A1N solid solution, resulting in that the strength of the steel substrate is affected.

The positive effect that the mass fraction of N is 0.006-0.01% is that N has strong solid solution strengthening effect in the tin-plated plate prepared from the steel matrix and can be used as a solid solution strengthening element, and N with proper mass fraction forms enough solid solution, so that the anisotropy of the tin-plated plate prepared from the steel matrix is reduced, and the strength of the tin-plated plate prepared from the steel matrix is improved; when the mass fraction is too large, the adverse effect is that too high N easily generates a large amount of solid solution, and the recrystallization temperature is raised, and the excessive solid solution precipitates to form surface defects.

As an alternative embodiment, the metallographic structure of the tin plate comprises, in volume fraction: ferrite: 97-99%, carbide: 1 to 3 percent.

In the application, the positive effect that the volume fraction of the ferrite is 97-99% is that enough ferrite can realize the high plasticity of the steel matrix in the volume fraction range; when the mass fraction is too large, the adverse effect is that the volume fraction of ferrite is too low, while when the volume fraction of carbide is too high, the strength of the steel matrix is too low or too high, and when the mass fraction is too small, the adverse effect is that too low ferrite needs to be further processed, thereby increasing the production difficulty.

The positive effect of 1-3% volume fraction of carbide is that within this volume fraction range, sufficient carbide will strengthen the steel matrix, preventing significant reduction in plasticity; when the range of the mass fraction is too large, an adverse effect is caused in that the content of ferrite is decreased by an excessive amount of carbide to reduce the plasticity of the steel matrix, and when the range of the mass fraction is too small, an adverse effect is caused in that the generation of a low content of carbide is difficult to industrially control.

Further, the grain size of the ferrite is 4.5 to 5.5 μm.

In the application, the positive effect that the grain size of the ferrite is 4.5-5.5 μm is that under the condition of the grain size, the ferrite is tightly arranged, so that the yield strength of the steel matrix can be improved, and the plasticity of the steel matrix is ensured; when the value range of the mass fraction is too large, the adverse effect is that ferrite with too large grain size leads to disordered arrangement before the ferrite, so that the yield strength of a steel matrix is reduced, and when the value range of the mass fraction is too small, the adverse effect is that the ferrite with too small grain size needs further treatment, so that the production control difficulty is large.

In one embodiment of the present application, there is provided a method of producing a low anisotropy, high strength and high elongation steel substrate, the method comprising:

s1, obtaining a casting blank containing the chemical components;

and S2, carrying out hot rolling, acid rolling, continuous annealing and leveling on the casting blank in sequence to obtain a steel matrix.

As an alternative embodiment, the hot rolling includes reheating, final rolling, and coiling; the reheating temperature is 1190-1230 ℃, the finishing temperature is 880-920 ℃, and the coiling temperature is 530-570 ℃.

In the application, the positive effect that the reheating temperature is 1190-1230 ℃ is to completely austenitize the plate blank, fully dissolve the N element and control the heating cost; when the value range of the temperature is too large, the heating cost is increased due to the excessively high temperature, and when the value range of the temperature is too small, the strength of the steel matrix is affected due to the fact that the austenite cannot be completely transformed due to the excessively low temperature.

The finish rolling temperature is 880-920 ℃, and the positive effect is that high-temperature finish rolling is adopted, so that finish rolling is in an austenite region, and the phenomenon of mixed crystals is avoided; when the value range of the temperature is too large, the adverse effect caused by the temperature is high temperature, the thickness of the surface iron scale of the steel matrix is increased, the surface quality is deteriorated, when the value range of the temperature is too small, the adverse effect caused by the temperature is that the finish rolling cannot be in an austenite region, the mixed crystal phenomenon is easy to occur, the performance in the middle of the steel matrix is uneven, and the strength of the tin plate is reduced.

The coiling temperature of 530-570 ℃ has the positive effects of inhibiting AlN precipitation and promoting carbide to be dispersed and precipitated in crystal, so that the difficulty of carbide precipitation in crystal in the continuous annealing stage can be reduced, and the stability of the coiling mechanical property of the strip steel is improved; when the value range of the temperature is too large, the adverse effect is that the temperature is high, too much coarse-grained carbide is generated, the coarse-grained carbide is precipitated at the grain boundary, the surface quality of a steel matrix is affected, when the value range of the temperature is too small, the adverse effect is that the temperature is low, the precipitation of carbide is inhibited, and the too low coiling temperature is difficult to industrialize.

As an alternative embodiment, the speed of the finish rolling is 11m/s to 15 m/s.

In the application, the positive effect that the final rolling speed is 11-15 m/s is that the A1N can be prevented from being separated out at the final rolling speed, the solid solution component of the tin plate is stabilized, the anisotropy is reduced, and the strength of the tin plate is improved; when the value range of the speed is too large, the adverse effect is that the finish rolling is insufficient due to the excessively high finish rolling speed, the retention time of the tin plate in an austenite region is short, and effective austenitization cannot be realized, so that the mixed crystal phenomenon occurs, and when the value range of the speed is too small, the adverse effect is that AIN is precipitated due to the excessively low finish rolling speed, so that the surface of the tin plate has defects.

As an optional embodiment, the continuous annealing comprises a soaking section and a quick cooling section, the temperature of the quick cooling section is less than or equal to 250 ℃, the cooling rate of the quick cooling section is 50-90K/s, and the temperature of the soaking section is 640-660 ℃.

In the application, the positive effect that the temperature of the rapid cooling section is less than or equal to 250 ℃ is that the carbide is refined and dispersed in ferrite grains as much as possible, the carbide is prevented from coarsening, and A1N is prevented from being separated out, so that the strength is improved; when the value range of the temperature is too large, the adverse effect is that the carbide is not fully refined due to the too high temperature of the rapid cooling section, and simultaneously the carbide is coarsened, AlN is precipitated, the strength is reduced, and the surface has defects.

The positive effect of the cooling rate of the fast cooling section being 50K/s-90K/s is that the proper cooling rate will avoid the coarsening of carbide and the generation of other abnormal structures; when the range of the cooling rate is too large, pearlite or martensite islands will be generated when the cooling rate is too high, resulting in reduced plasticity of the steel matrix, and when the range of the cooling rate is too small, resulting in an adverse effect that the cooling rate is too low, resulting in coarsening of carbides, resulting in increased difficulty in producing the steel matrix.

The positive effect of the continuous annealing temperature of 640-660 ℃ is to ensure that fine ferrite grains are formed so as to ensure the strength; when the value range of the temperature is too large, the adverse effect is that the temperature is too high, grains are coarsened, and the surface quality of a steel matrix is affected.

As an alternative embodiment, the reduction rate of the acid rolling is more than or equal to 87 percent.

In the application, the reduction rate of acid rolling is more than or equal to 87 percent, and the positive effects of crushing crystal grains, refining annealed crystal grains, promoting carbide to be separated out from the crystal in the annealing process and improving the strength are achieved; when the value range of the reduction ratio is too small, the adverse effect is that the too low reduction ratio cannot break crystal grains, so that the carbide cannot be promoted to be separated out from the crystal grains in the annealing process, and the strength is improved.

As an alternative embodiment, the flat elongation is between 2% and 3%.

In the application, the positive effect of the flat elongation of 2-3% is that the final yield strength can be controlled; when the value range of the leveling elongation is too large, the adverse effect is that the leveling elongation is too high, the anisotropy of the steel matrix is increased, and when the value range of the leveling elongation is too small, the adverse effect is that the leveling elongation is too low, the yield strength of the steel matrix is too low, and the production difficulty is increased.

In one embodiment of the present application, there is provided a low-anisotropy, high-strength and high-elongation tin-plated sheet comprising a steel substrate and a tin-plated layer covering at least one surface of the steel substrate; the steel matrix is the steel matrix with the chemical components.

In one embodiment of the present application, as shown in fig. 2, there is provided a method for producing a low-anisotropy, high-strength, and high-elongation steel substrate, the method including:

s1, carrying out tin plating on the steel substrate to obtain a tin-plated plate.

Example 1

A low-anisotropy high-strength high-elongation tin plate comprises a steel substrate and a tin coating; the chemical composition of the steel matrix comprises the following components in percentage by mass: c: 0.07%, Si: 0.007%, Mn: 0.39%, P: 0.01%, S: 0.006%, Als:

0.011%, N: 0.0062% and the balance of Fe and impurities.

The metallographic structure of the tin plate comprises, in volume fraction: ferrite: 98%, carbide: 2 percent.

The grain size of ferrite was 5.2 μm.

A preparation method of a low-anisotropy high-strength high-elongation tin plate comprises the following steps:

s1, obtaining a casting blank containing chemical components;

Hot rolling including reheating, finish rolling and coiling; the reheating temperature was 1195 ℃, the finish rolling temperature was 899 ℃ and the coiling temperature was 567 ℃.

The speed of the final rolling was 13.5 m/s.

The continuous annealing comprises a soaking section and a quick cooling section, wherein the temperature of the quick cooling section is 248 ℃, and the temperature of the soaking section is 655 ℃.

The reduction rate of the acid rolling was 90%.

The flat elongation was 2.2%.

The tin-plated plate comprises a steel substrate and a tin-plated layer, wherein the tin-plated layer covers at least one surface of the steel substrate; the steel matrix is the steel matrix with the chemical components.

As shown in fig. 2, a method for preparing a low-anisotropy, high-strength and high-elongation steel substrate includes:

s1, carrying out tin plating on a steel substrate to obtain a tin-plated plate.

Example 2

Comparing example 2 with example 1, example 2 differs from example 1 in that:

a tin plate with low anisotropy, high strength and high elongation comprises the following chemical components in percentage by mass: c: 0.08%, Si: 0.015%, Mn: 0.55%, P: 0.011%, S: 0.004%, Als: 0.016%, N: 0.0084%, and the balance of Fe and impurities.

The metallographic structure of the tin plate comprises, in volume fraction: ferrite: 97%, carbide: 3 percent.

The grain size of ferrite was 4.8. mu.m.

The reheating temperature was 1227 ℃, the finishing temperature was 911 ℃ and the coiling temperature was 544 ℃.

The speed of the final rolling was 14.3 m/s.

The continuous annealing comprises a soaking section and a quick cooling section, wherein the temperature of the quick cooling section is 233 ℃, and the temperature of the soaking section is 654 ℃.

The reduction rate of the acid rolling was 91%.

The flat elongation was 2.8%.

Example 3

Comparing example 3 with example 1, example 3 differs from example 1 in that:

a tin plate with low anisotropy, high strength and high elongation comprises the following chemical components in percentage by mass: c: 0.06%, Si: 0.02%, Mn: 0.35%, P: 0.015%, S: 0.012%, Als: 0.005%, N: 0.006%, the balance being Fe and impurities.

The metallographic structure of the tin plate comprises, in volume fraction: ferrite: 99%, carbide: 1 percent.

The grain size of ferrite was 4.5 μm.

The reheating temperature was 1190 ℃, the finish rolling temperature was 880 ℃ and the coiling temperature was 530 ℃.

The speed of the final rolling was 11 m/s.

The continuous annealing comprises a soaking section and a quick cooling section, wherein the temperature of the quick cooling section is 250 ℃, and the temperature of the soaking section is 640 ℃.

The reduction rate of the acid rolling was 87%.

Example 4

Comparing example 4 with example 1, example 4 differs from example 1 in that:

a tin plate with low anisotropy, high strength and high elongation comprises the following chemical components in percentage by mass: c: 0.08%, Si: 0.02%, Mn: 0.6%, P: 0.015%, S: 0.012%, Als: 0.02%, N: 0.01%, and the balance of Fe and impurities.

The grain size of ferrite was 5.5 μm.

The reheating temperature is 1230 ℃, the finishing temperature is 920 ℃, and the coiling temperature is 570 ℃.

The speed of the final rolling was 15 m/s.

The temperature of the soaking section is 660 ℃.

Comparative example 1

Comparing comparative example 1 with example 1, comparative example 1 differs from example 1 in that:

no Mn element is added in the chemical composition of the steel matrix.

Comparative example 2

Comparing comparative example 2 with example 1, comparative example 2 differs from example 1 in that:

n in chemical compositions of a steel matrix: 0.011 percent.

Comparative example 3

Comparing comparative example 3 with example 1, comparative example 3 differs from example 1 in that:

c in chemical compositions of a steel matrix: 0.081 percent.

Comparative example 4

Comparing comparative example 4 with example 1, comparative example 4 differs from example 1 in that:

the reheating temperature was 1180 ℃, the finish rolling temperature was 870 ℃, and the coiling temperature was 500 ℃.

The speed of the final rolling was 10 m/s.

The continuous annealing comprises a soaking section and a quick cooling section, wherein the temperature of the quick cooling section is 240 ℃, and the temperature of the soaking section is 600 ℃.

The reduction rate of the acid rolling was 85%.

Comparative example 5

Comparing comparative example 5 with example 1, comparative example 5 differs from example 1 in that:

The speed of the final rolling was 20 m/s.

The temperature of the soaking section is 670 ℃.

Related experiments:

each of the tin-plated sheets of examples 1 to 4 and comparative examples 1 to 5 was collected, and the performance of each tin-plated sheet was examined, and the results are shown in Table 1.

Test methods of the related experiments:

yield strength after longitudinal aging: measurements were performed according to GB/T2520.

Elongation percentage: measurements were performed according to GB/T2520.

The yield strength after three-dimensional aging is extremely poor: the measurement is carried out according to GB,/T2520, and the average value of the difference between the maximum value and the minimum value of the three-way yield strength after longitudinal, 45-degree and transverse ageing is taken.

TABLE 1

Specific analysis of table 1:

the yield strength after longitudinal aging refers to the yield limit of the produced tin plate at the time of the yield phenomenon, namely, the stress resisting micro plastic deformation, and the higher the yield strength is, the higher the yield limit of the tin plate is.

The elongation is an index of the plastic property of the tin plate, and the higher the elongation is, the stronger the plastic property of the tin plate is.

The extremely poor yield strength after three-dimensional aging refers to the average value of the difference between the maximum value and the minimum value of the three-dimensional yield strength after longitudinal aging, 45 degrees and transverse aging, and the lower the extremely poor yield strength after three-dimensional aging is, the lower the anisotropy of the tin plate is, and the higher the strength of the tin plate is indirectly.

From the data in examples 1-4, it can be seen that:

by adopting the steel matrix chemical composition and the method of the tin plate, the tin plate with relatively ideal yield strength and elongation after longitudinal aging and extremely poor yield strength after three-dimensional aging can be obtained.

From the data of comparative examples 1 to 5, it can be seen that:

if the Mn element or the C and N elements are not added in the mass fraction range of the tin plate, the yield strength and the elongation of the tin plate after longitudinal aging are reduced, and the yield strength is increased extremely badly after three-dimensional aging.

One or more technical solutions in the embodiments of the present application at least have the following technical effects or advantages:

(1) according to the method provided by the embodiment of the application, the tin-plated plate product with high yield strength and high elongation can be obtained by controlling the chemical components of the tin-plated plate steel substrate and the process parameters of the preparation method.

(2) The method provided by the embodiment of the application can realize the production of the tin plate with the yield strength of 430 MPa-490 MPa after longitudinal aging, the elongation of more than or equal to 15% and the yield strength range of less than or equal to 20MPa after three-dimensional aging by a one-time cold rolling process.

(3) According to the method provided by the embodiment of the application, the technological parameters can be integrated on an automatic production line of the tin plate, the reheating temperature, the finish rolling speed and the coiling temperature of hot rolling are regulated, the reduction rate of acid rolling is regulated, the continuous annealing temperature and the temperature of a quick cooling section are integrated in a control console, and finally the leveling elongation rate is integrated in the control console, so that the automatic production of the tin plate can be realized, and the technological time is further saved.

The drawings illustrate:

fig. 3 is a schematic diagram of the metallographic structure of the tin plate according to the embodiment of the present application, and it can be seen from fig. 2 that when the method of the present application is used, fine-grained ferrite, carbide structures with fine dispersion distribution in the grains as the main component and part of grain boundary distribution can be obtained.

It is noted that, in this document, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, 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. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The foregoing are merely exemplary embodiments of the present invention, which enable those skilled in the art to understand or practice the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A low-anisotropy, high-strength and high-elongation steel matrix, characterized in that the chemical composition of the steel matrix comprises, in mass fraction: c: 0.06-0.08%, Si is less than or equal to 0.02%, Mn: 0.35-0.6%, P is less than or equal to 0.015%, S is less than or equal to 0.012%, Als: 0.005% -0.02%, N: 0.006-0.01 percent, and the balance of Fe and impurities.

2. Steel substrate according to claim 1, wherein the metallographic structure of the steel substrate comprises, in volume fraction: ferrite: 97-99%, carbide: 1 to 3 percent.

3. Steel substrate according to claim 2, characterised in that the grain size of the ferrite is between 4.5 μm and 5.5 μm.

4. A method of producing the steel substrate according to any one of claims 1 to 3, characterised in that the method comprises: obtaining a casting blank containing the chemical components;

5. The method of claim 4, wherein the hot rolling comprises reheating, final rolling, and coiling; the reheating temperature is 1190-1230 ℃, the finishing temperature is 880-920 ℃, and the coiling temperature is 530-570 ℃.

6. The method according to claim 4, characterized in that the speed of the final rolling is between 11 and 15 m/s.

7. The method according to claim 4, wherein the continuous annealing comprises a soaking section and a rapid cooling section, the temperature of the rapid cooling section is less than or equal to 250 ℃, the cooling rate of the rapid cooling section is 50K/s to 90K/s, and the temperature of the soaking section is 640 ℃ to 660 ℃.

8. The method of claim 4, wherein the reduction rate of the acid rolling is more than or equal to 87%.

9. A tin-plated sheet with low anisotropy, high strength and high elongation is characterized in that the tin-plated sheet comprises a steel substrate and a tin-plated layer, wherein the tin-plated layer covers at least one surface of the steel substrate;

the steel substrate comprising the steel substrate according to any one of claims 1 to 3.

10. A method of making the tin-plated sheet of claim 9, comprising:

and carrying out tin plating on the steel substrate to obtain a tin-plated plate.