JP4081823B2 - Manufacturing method of steel plate for cans by annealing skipping process - Google Patents

Description

【００３４】
【表２】

【００３５】
【表３】

【００３６】
表２、表３から、熱間仕上げ圧延を本発明法に従うエンドレス圧延で行い、所定の温度で巻取ることにより、軟質で局部延性能の高い鋼板が得られることがわかる。また、温間圧延の場合に、特に仕上げ圧延の最終パスを強圧下することは熱延板の自己再結晶に効果的であることがわかる。これらの鋼板組織は、従来工程で焼鈍したものと同等の組織であり、焼鈍工程を省略しても、従来の焼鈍工程を含む工程によって製造したものとほぼ同等の成形性を得ることが可能であることが金属組織のうえからも確認された。
なお、表３のNo. ２〜４は自己再結晶が不十分なためフランジ成形性が悪化した。
【００３７】
【発明の効果】
上述したように、本発明方法によれば、焼鈍を行わない低コストの製造工程で、耐リジング性および伸びフランジ性などの加工性に優れる缶用鋼板を製造することが可能となる。
また、本発明方法によれば、この省プロセス工程で、材質均一性が改善され、歩留りが向上するので、品質が安定した缶用鋼板をより一層低コストで製造することが可能になる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a steel plate for a process-saving can that omits annealing after cold rolling, and is particularly excellent in workability such as ridging resistance and stretch flangeability, and excellent in material uniformity. The present invention relates to a method for producing a steel plate for cans suitable for use as a thin plate or tin-free steel.
[0002]
[Prior art]
Beverage cans and container cans such as 18-liter cans and pail cans are roughly classified into two-piece cans and three-piece cans from the manufacturing method (process). 2-piece cans are surface-drawn steel sheets that have undergone tin plating, chrome plating, chemical conversion, oiling, etc., shallow drawing, DWI (Drawn and Wall Ironed) processing, DRD (Drawn and Redrawn) processing, etc. The can bottom is made up of a single piece and the can body is integrally formed, and a lid is attached to the can bottom. A three-piece can is a three-piece can made by bending the surface-treated steel sheet into a cylindrical or rectangular tube shape, joining the ends together to form a can body, and then attaching a canopy and a bottom cover to the can. is there.
[0003]
Since the cost of the can made in this way has a high proportion of the material cost, the demand for reducing the cost of the steel sheet is strong.
A promising method for responding to this is a technique such as Japanese Patent Publication No. 63-10213, which employs continuous annealing, which is high in production efficiency and excellent in yield and surface quality, instead of conventional box annealing. In addition, improvements have been made to the manufacturing technology of steel sheets for cans that are as soft as T2 (50-56) with a refining degree expressed by the value of Rockwell hardness (HR30T). Furthermore, a technique for producing a soft steel sheet by continuous annealing has also been developed. For example, as disclosed in Japanese Patent Publication No. 1-52452, an extremely low carbon steel is applied as a material, and various combinations of work hardening after annealing can be used. A technique for making steel plates for cans of different hardness has been proposed.
[0004]
Even in this type of steel plate for cans, there is a demand for further cost reduction. In order to meet this demand, efforts have been made to develop new manufacturing techniques. One method for reducing the cost is to reduce the thickness of the steel sheet to be used and to strengthen the neck diameter reduction of the upper lid. Even more stringent properties are required for materials applied to these methods, and can steel plates with good workability could not be produced by methods other than the conventional processes described above.
As another technology aiming at further cost reduction, Japanese Patent Application Laid-Open No. 4-280926 discloses that after subjecting an ultra-low carbon steel as a raw material to hot rolling in the α region, it is self-annealed to grow crystal grains. The manufacturing method by the process-saving process which omits subsequent annealing and temper rolling by performing cold rolling is disclosed.
[0005]
[Problems to be solved by the invention]
However, the steel sheet produced by this method has a problem that ridging (striated defects generated during processing) peculiar to α-region hot rolling occurs and stretch flangeability is not so good.
Accordingly, the object of the present invention is to solve the problems of the above-described conventional technology, and to perform canning that is excellent in workability such as ridging resistance and stretch flangeability in a low-cost manufacturing process that does not perform annealing and saves process. The purpose is to propose a technology for manufacturing steel sheets.
Another object of the present invention is to propose a technique for stably producing a steel plate for cans which is excellent in material uniformity in this process-saving process.
[0006]
[Means for solving problems]
In order to achieve the above-mentioned object, the present inventors first examined the characteristics required as a steel plate for cans and concluded as follows.
1) Unlike deep drawing steel sheets used in automobiles, a high r value is not an essential condition.
2) It is desirable that the in-plane anisotropy (Δr) of the r value is small.
3) It is desirable that non-uniform deformation such as ridging does not occur.
4) A fine structure is desirable in terms of uniform deformation.
5) The manufactured steel sheet does not necessarily need to be completely non-aged like a box annealed material (low carbon aluminum killed steel), but in a normal continuous annealed material (low carbon aluminum killed steel), a can-making process and 2 It is desirable not to age because the next and third steps cause problems.
6) It is desirable to have local ductility at a strain rate that is about 1 to 2 orders of magnitude faster than those obtained by normal tensile tests.
The present invention has been conceived by conducting metallurgical studies on the steel composition and production conditions that govern the above-mentioned characteristics as a steel plate for cans. That is, the gist configuration of the present invention is as follows.
[0007]
(1) C: 0.0030 wt% or less, Si: 0.02 wt% or less, Mn: 0.05 to 0.5 wt%, P: 0.02 wt% or less, S: 0.02 wt% or less, solAl: 0. A steel slab containing 1 wt% or less, N: 0.0030 wt% or less, with the balance being Fe and inevitable impurities, is roughly rolled, the obtained sheet bar is joined to the preceding sheet bar, and then the end temperature Is Ar₃Finish rolling so as to be −50 ° C. or more, winding in a temperature range of 640 to 750 ° C., removing the scale, and cold rolling at a rolling reduction of 40 to 90%, and then 200 to 300 ° C. for 5 seconds. After the cold rolling characterized by performing the above heat holding heat treatmentRecrystallizationA method for producing steel sheets for cans, in which annealing is omitted.
[0008]
(2) C: 0.0030 wt% or less, Si: 0.02 wt% or less, Mn: 0.05 to 0.5 wt%, P: 0.02 wt% or less, S: 0.02 wt% or less, solAl: 0. A steel slab containing 1 wt% or less, N: 0.0030 wt% or less, with the balance being Fe and inevitable impurities, is roughly rolled, the obtained sheet bar is joined to the preceding sheet bar, and then the end temperature Is Ar₃After finishing rolling under lubrication so as to be less than −50 ° C., winding and self-annealing in a temperature range of 600 to 750 ° C., removing the scale, and cold rolling at a rolling reduction of 40 to 90%, After the cold rolling characterized by performing a heat holding heat treatment at 200 to 300 ° C. for 5 seconds or moreRecrystallizationA method for producing steel sheets for cans, in which annealing is omitted.
[0009]
(3) C: 0.0030 wt% or less, Si: 0.02 wt% or less, Mn: 0.05 to 0.5 wt%, P: 0.02 wt% or less, S: 0.02 wt% or less, solAl: 0. 1 wt% or less, N: 0.0030 wt% or less, and Nb: 0.002 to 0.02 wt%, Ti: 0.001 to 0.02 wt%, or one or two of them, with the balance being Fe and A steel slab having a composition composed of inevitable impurities is roughly rolled, and the obtained sheet bar is joined to the preceding sheet bar, and then the end temperature is Ar.₃Finish rolling so as to be −50 ° C. or more, winding in a temperature range of 640 to 750 ° C., removing the scale, and cold rolling at a rolling reduction of 40 to 90%, and then 200 to 300 ° C. for 5 seconds. After the cold rolling characterized by performing the above heat holding heat treatmentRecrystallizationA method for producing steel sheets for cans, in which annealing is omitted.
[0010]
(4) C: 0.0030 wt% or less, Si: 0.02 wt% or less, Mn: 0.05 to 0.5 wt%, P: 0.02 wt% or less, S: 0.02 wt% or less, solAl: 0. 1 wt% or less, N: 0.0030 wt% or less, and Nb: 0.002 to 0.02 wt%, Ti: 0.001 to 0.02 wt%, or one or two of them, with the balance being Fe and A steel slab having a composition composed of inevitable impurities is roughly rolled, and the obtained sheet bar is joined to the preceding sheet bar, and then the end temperature is Ar.₃After finishing rolling under lubrication so as to be less than −50 ° C., winding and self-annealing in a temperature range of 600 to 750 ° C., removing the scale, and cold rolling at a rolling reduction of 40 to 90%, After the cold rolling characterized by performing a heat holding heat treatment at 200 to 300 ° C. for 5 seconds or moreRecrystallizationA method for producing steel sheets for cans, in which annealing is omitted.
(5) C: 0.0030 wt% or less, Si: 0.02 wt% or less, Mn: 0.05 to 0.5 wt%, P: 0.02 wt% or less, S: 0.02 wt% or less, solAl: 0. A steel slab containing 1 wt% or less, N: 0.0030 wt% or less, with the balance being Fe and inevitable impurities, is roughly rolled, the obtained sheet bar is joined to the preceding sheet bar, and then the end temperature Is Ar₃Finish rolling so as to be −50 ° C. or higher, winding in a temperature range of 640 to 750 ° C., removing the scale, cold rolling at a rolling reduction of 40 to 90%, performing surface treatment, After the cold rolling characterized by performing a heat holding heat treatment at 200 to 300 ° C. for 5 seconds or moreRecrystallizationA method for producing steel sheets for cans, in which annealing is omitted.
(6) C: 0.0030 wt% or less, Si: 0.02 wt% or less, Mn: 0.05 to 0.5 wt%, P: 0.02 wt% or less, S: 0.02 wt% or less, solAl: 0. A steel slab containing 1 wt% or less, N: 0.0030 wt% or less, with the balance being Fe and inevitable impurities, is roughly rolled, the obtained sheet bar is joined to the preceding sheet bar, and then the end temperature Is Ar₃After finishing rolling under lubrication so as to be less than −50 ° C., winding and self-annealing in a temperature range of 600 to 750 ° C., removing the scale, and cold rolling at a rolling reduction of 40 to 90%, Surface treatment is performed, and then heat holding heat treatment is performed at 200 to 300 ° C. for 5 seconds or more.RecrystallizationA method for producing steel sheets for cans, in which annealing is omitted.
(7) C: 0.0030 wt% or less, Si: 0.02 wt% or less, Mn: 0.05 to 0.5 wt%, P: 0.02 wt% or less, S: 0.02 wt% or less, solAl: 0. 1 wt% or less, N: 0.0030 wt% or less, and Nb: 0.002 to 0.02 wt%, Ti: 0.001 to 0.02 wt%, or one or two of them, with the balance being Fe and A steel slab having a composition composed of inevitable impurities is roughly rolled, and the obtained sheet bar is joined to the preceding sheet bar, and then the end temperature is Ar.₃Finish rolling so as to be −50 ° C. or higher, winding in a temperature range of 640 to 750 ° C., removing the scale, cold rolling at a rolling reduction of 40 to 90%, performing surface treatment, After the cold rolling, characterized by performing a heat holding heat treatment at 200 to 300 ° C. for 5 seconds or moreRecrystallizationA method for producing steel sheets for cans, in which annealing is omitted.
(8) C: 0.0030 wt% or less, Si: 0.02 wt% or less, Mn: 0.05 to 0.5 wt%, P: 0.02 wt% or less, S: 0.02 wt% or less, solAl: 0. 1 wt% or less, N: 0.0030 wt% or less, and Nb: 0.002 to 0.02 wt%, Ti: 0.001 to 0.02 wt%, or one or two of them, with the balance being Fe and A steel slab having a composition composed of inevitable impurities is roughly rolled, and the obtained sheet bar is joined to the preceding sheet bar, and then the end temperature is Ar.₃After finishing rolling under lubrication so as to be less than −50 ° C., winding and self-annealing in a temperature range of 600 to 750 ° C., removing the scale, and cold rolling at a rolling reduction of 40 to 90%, Surface treatment is performed, and then heat holding heat treatment is performed at 200 to 300 ° C. for 5 seconds or more.RecrystallizationA method for producing steel sheets for cans, in which annealing is omitted.
(9) The method for producing a steel plate for a can according to any one of the above (5) to (8), wherein the surface treatment is any one of tin plating, chromium plating, chemical conversion treatment and oil coating. .
[0011]
(10) The finish rolling speed is 1000 m / min or more at the exit side speed of the final stage, and the speed fluctuation amount is 10% or less.Above (1) to (9The manufacturing method of the steel plate for cans in any one of 2).
[0014]
DETAILED DESCRIPTION OF THE INVENTION
In order to improve the r value, it is necessary to perform recrystallization annealing after cold rolling. However, if a very large r value is not required, the recrystallization annealing step can be omitted. However, the steel sheet as it is cold-rolled in the conventional method according to the cold rolling → annealing → secondary rolling process, which simply omits the recrystallization annealing process, has a particularly low degree of ductility and stretch flangeability as steel sheets for cans. However, it was not possible to satisfy the requirements for applications that require high drawability. Moreover, in order to suppress ridging and improve stretch flangeability, the objective cannot be achieved by simply recrystallizing crystal grains as much as possible, as aimed by JP-A-4-280926.
[0015]
Therefore, as a result of diligent research to solve the above problems, the inventors used steel whose components were appropriately controlled, and optimized the heat treatment conditions of the hot rolling process to perform the annealing process after cold rolling. It has been found that it can be omitted, and even if the structure of the steel is somewhat fine, it is effective to avoid remixing uniformly and avoid remixing.
In order to obtain recrystallized grains satisfying such conditions, it is extremely effective to perform so-called “endless rolling” in which the sheet bar is joined to the preceding sheet bar in the hot rolling process and finish-rolled in an endless state. I found out that
Moreover, it has been found that the endless rolling improves the uniformity of the material in the coil. This is because, in the case of steel plates for cans, the thickness of the hot-rolled plate is thin, and it is difficult to maintain the finishing temperature and the winding temperature uniformly throughout the coil. Endless rolling plays a major role, meaning that it is possible to solve the problem that has become a bottleneck in manufacturing steel plates for cans, such as the inability to cause the entire coil to crystallize.
[0016]
  Hereinafter, the reason why the steel composition and the production conditions are limited as described above in the present invention will be described.
C:0.0030wt% or less
  C is its content0.0030If the amount exceeds 50%, the amount of residual solid solution carbon increases, so that sufficient local ductility necessary at the time of can molding cannot be obtained. This is not preferable because it causes cracking during flange molding. Further, if the amount of carbon is further increased, the work hardening amount increases, the strength of the material increases, which causes wrinkles during squeezing and becomes a problem during welding. Furthermore, it is necessary to limit the amount of C from the viewpoint of aging degradation..
[0017]
Si: 0.02 wt%Less than
  Si is an element that deteriorates the surface properties of the steel sheet, and if the amount added is too large, it is not desirable as a surface-treated steel sheet. Moreover, the steel is hardened, making the hot rolling process difficult, and the steel as the final product is hardened, which is undesirable. For these reasons, the Si content is 0.02 wt% or less. In particular, it is desirable that the content be 0.010% or less in applications where the surface property requirement is strict.
[0018]
Mn: 0.05-0.50wt%
Mn is an element useful for preventing surface cracks caused by hot brittleness due to S, and at least 0.05 wt% is necessary to obtain the effect. On the other hand, if it exceeds 0.50 wt%, the transformation point becomes too low and hardens, adversely affects the cold workability thereafter and hardens the product plate. Therefore, the Mn content is 0.05 to 0.50 wt%. In order to obtain a soft steel plate for cans, the content is preferably 0.20% or less.
[0019]
P: 0.02wt% or less
P is an element harmful to corrosion resistance, and the corrosion resistance is improved by reducing the content, but excessive reduction leads to an increase in production cost. For these reasons, the P content is set to 0.02 wt% or less. In order to significantly improve the workability, it is preferably 0.010 wt% or less.
[0020]
S: 0.02wt% or less
When the amount of S increases, inclusions such as MnS increase, and the local ductility typified by stretch flangeability is reduced, and the total elongation is remarkably improved. Therefore, the S content needs to be limited to 0.02 wt% or less. In order to remarkably improve the workability, it is preferable that the content is 0.006 wt% or less and Mn / S is 10 or more.
[0021]
sol Al: 0.10wt% or less
Although sol Al is an element necessary for deoxidation, when it exceeds 0.10 wt%, not only the deoxidation effect is saturated but also inclusions increase, which adversely affects moldability. Therefore, the content of sol Al is 0.10 wt% or less. In order to secure stable production conditions, it is preferable that the range be 0.020 to 0.040 wt%.
[0022]
N: 0.0030wt% or less
N is an impurity element inevitably mixed in the steel, and forms a precipitate to cause a decrease in elongation. Further, when N remains in a solid solution state, the steel is hardened. The strength of the steel sheet according to the method of the present invention is sufficient, but rather a softer one is desired. Therefore, the upper limit of N content is 0.0030 wt%. In view of workability, the content is preferably 0.0020 wt% or less.
[0023]
By adding one or two of Nb and Ti in addition to the above basic components, the softening of the steel can be achieved.
Nb: 0.002 to 0.02 wt%, Ti: 0.001 to 0.02 wt%
Nb and Ti are elements useful for reducing the aging property and softening the steel due to carbon fixation. In order to obtain these effects, the Nb and Ti contents must be at least 0.002 wt% and 0.001 wt%, respectively. On the other hand, if any element is added in excess of 0.020 wt%, the homogeneity of hot-rolled sheet recrystallized grains is impaired, not only forming a non-uniform structure, but also increasing the load during hot rolling. For this reason, the Nb and Ti contents are 0.002 to 0.02 wt% and 0.001 to 0.02 wt%, respectively. In addition, when emphasizing workability, it is desirable that all be in the range of 0.005 to 0.015 wt%.
[0024]
Next, manufacturing conditions will be described including the reason for limitation.
(1) Hot rolling
Slab heating temperature:
If the slab heating temperature is too high, fine precipitates are deposited in the middle of hot rolling, and the pinning effect thereby makes the grain size of the hot rolled plate fine. As a result, the hot-rolled sheet is easily hardened, and the local deformability is lowered, which is not preferable. Therefore, it is desirable that the slab heating temperature is 1250 ° C. or less, and the precipitates are coarsened to achieve both formability and softening. Preferably, the temperature is set to 1100 ° C. or lower, and precipitates such as MnS are coarsely precipitated during slab heating, and the particle diameter after hot rolling is relatively large.
[0025]
Endless rolling:
Endless rolling is a particularly important component in the method of the present invention.
In the conventional rolling method for thin steel sheets, the coil tip flutters up to the beginning of winding, and the cooling conditions associated therewith are uneven. Therefore, the line speed cannot be increased, and then coil winding starts and tension is increased. When it became possible to increase the speed, the productivity was increased. In such a conventional method, it is unavoidable that the rolling conditions, particularly the rolling speed, vary greatly in the longitudinal direction of the coil as well as in the front and rear ends of the coil.
[0026]
This phenomenon is remarkably disadvantageous for improving the workability in the annealing omitting process aimed at by the present invention. To solve the phenomenon, it is important to control the rolling speed within a certain range. Specifically, it is desirable that the exit rolling speed of finish rolling is 1000 m / min or more, more preferably 1200 m / min or more, and the amount of speed fluctuation in the coil is 10% or less, more preferably 5% or less, Stable workability is obtained by performing finish rolling under these conditions. The rolling speed is also affected by the amount of Nb, the amount of reduction, the cooling conditions, and the like, and may be controlled in consideration of these operating factors within the appropriate range.
[0027]
Further, when the material uniformity is required in the longitudinal direction of the coil as in the case of a steel plate for cans, in the normal hot rolling method, the hot rolling conditions (finishing temperature, (Cooling cycle) Many parts become detached and the yield decreases.
In particular, the component composition targeted by the method of the present invention has a relatively high transformation point, so the coil tip and rear end are likely to have a finish below the transformation point (below −50 ° C.), resulting in residual or abnormal textures. It is easy to invite the generation of grains, and Ar_ThreeWhen rolling is completed in a relatively low temperature region below the transformation point, it becomes difficult to recrystallize the entire coil due to the self-annealing effect. In order to eliminate such disadvantages, it is essential to perform endless rolling.
For the reasons described above, it is important to perform endless rolling in order to make the material uniform.
[0028]
Finishing temperature:
In order to make the structure and grain size of the hot rolled sheet uniform, (Ar)_ThreeTransformation point -50 ° C) or higher, preferably Ar_ThreeIt must be above the transformation point. By making the finishing temperature higher than the transformation point, it can be expected that the structure is made more uniform, but considering the influence of the processed structure and its fraction, Ar_ThreeUp to -50 ° C transformation point is acceptable.
In addition, to reduce costs, Ar_ThreeA temperature lower than the transformation point (Ar_ThreeWhen hot rolling is performed at a temperature lower than the transformation point of −50 ° C., so-called warm lubrication rolling, in which rolling is performed under lubrication, can also be performed. In this case, sufficient recrystallization (self-annealing) after winding is important for obtaining workability. For that purpose, the final pass is strongly reduced, specifically, 20% in the final pass. It is desirable to perform the above strong pressure. In any case, if a coarse structure remains after finishing below the transformation point, 1) ridging occurs, and 2) after cold rolling, the material hardness in the sheet thickness direction becomes non-uniform, and cans are made. It also causes the flange cracking, so it is necessary to avoid the formation of such a structure. Accordingly, when performing warm rolling, it is essential to perform endless rolling while ensuring uniform reduction by applying lubrication such as oil lubrication. Note that the lower limit temperature of the warm rolling is not particularly limited as long as the winding temperature described later can be secured.
[0029]
Winding temperature:
The coiling temperature is determined by recrystallization (Ar_ThreeIn order to promote grain growth, it is desirable that Ar is hot-rolled at a transformation point of less than -50 ° C._ThreeWhen hot rolling at a transformation point of -50 ° C or higher, 640 ° C or higher, and Ar_ThreeWhen hot rolling is performed at a transformation point below -50 ° C, a temperature of 600 ° C or higher is required. However, when the temperature exceeds 750 ° C., the scale thickness increases remarkably, and the descalability during pickling deteriorates. In actual operation, it is difficult to wind up at 750 ° C or higher. For this reason, the winding temperature is (Ar_ThreeWhen hot rolling is performed at a transformation point of -50 ° C or higher, the temperature is set to 640 to 750 ° C._ThreeWhen hot rolling is performed below the transformation point (-50 ° C), the temperature is set to 600 to 750 ° C.
[0030]
(2) Cold rolling
Cold rolling after pickling needs to be performed at a rolling reduction of 40 to 90%. Since the grain size of the hot-rolled mother plate in the method of the present invention is relatively large, the material may be non-uniform unless cold rolling is performed at a rolling reduction of 40% or more. The upper limit is 90% from the viewpoint of local ductility because the strength is sufficient in consideration of the application. However, considering moldability further, it is desirable to make it 80% or less.
[0031]
(3) Heat treatment after cold rolling In the method of the present invention, it is possible to soften and increase the local deformability by subjecting the cold-rolled steel plate to a heat treatment in a low temperature range, and a subsequent can manufacturing process. Thus, it becomes easy to perform molding such as flange molding. In this case, as heat treatment conditions, it is desirable that the temperature is 200 ° C. or more and the time is 5 seconds or more. If the heat treatment temperature and time are less than this, the strain accumulated by cold rolling will not be recovered and will not soften. In addition, carbon and nitrogen remaining in the steel are not preferable because there is a risk of hardening. Also, the heating temperature is300If it exceeds ℃, there is a risk of excessive softening due to recrystallization and the like, and there is also a concern of deterioration such as temper color on the surface of the steel sheet or plating.300℃. Here, the holding time is desirably 10 seconds to 30 minutes. In the normal can manufacturing process, steel sheets and steel sheets with surface treatment (tin plating, chromate treatment, etc.) subjected to surface treatment (tin plating, chromate treatment, etc.) are subjected to paint baking or film laminating treatment in a can manufacturing line, and then can manufacturing Processed. Here, during the coating baking or film laminating process, the steel sheet is heated to a temperature of 200 ° C. or higher for a time of 5 seconds or longer, and therefore this step can be combined with the low-temperature heating step.
[0032]
【Example】
Steels having the chemical components shown in Table 1 were melted and subjected to rough rolling, finish rolling (endless rolling or normal rolling for comparison) and winding under the conditions shown in Table 2, followed by pickling. Cold rolling was performed at the rolling reduction shown in the table, and some of the samples were heated to 210 ° C. and held for 20 minutes.
The obtained specimens were examined for tensile properties, Rockwell hardness and flange formability. Here, the tensile test was performed using a JIS No. 5 test piece, and the scale of Rockwell hardness was HR30T. Flange formability is equivalent to # 25 equivalent tin plating under normal conditions, then formed into roll can and high-speed seam welding to form the equivalent of a 3-piece can body, and stretched and flanged to produce cracks. Judgment was made based on the presence or absence of. A sample was extracted from the entire length of the coil, the formability at each part was evaluated, and the yield was determined from the defect rate. These results are shown together in Table 2.
Further, endless hot rolling was performed at a temperature equal to or lower than the transformation point using the steel A shown in Table 1, and at that time, the lubrication conditions and the rolling reduction of the final pass in the finish rolling were variously changed. This material was cold-rolled at a cold rolling reduction rate of 70%, and a part of the material was heat-treated at 210 ° C. and held for 20 minutes. A similar test was performed on the obtained specimen. The results are shown in Table 3 together with the production conditions.
[0033]
[Table 1]

[0034]
[Table 2]

[0035]
[Table 3]

[0036]
From Tables 2 and 3, it can be seen that a hot steel sheet having high local elongation performance can be obtained by performing hot finish rolling by endless rolling according to the method of the present invention and winding at a predetermined temperature. In addition, in the case of warm rolling, it can be seen that it is effective for the self-recrystallization of the hot-rolled sheet to particularly reduce the final pass of the finish rolling. These steel sheet structures are the same structure as those annealed in the conventional process, and even if the annealing process is omitted, it is possible to obtain a formability substantially the same as that manufactured by the process including the conventional annealing process. It was confirmed from the metal structure.
Note that Nos. 2 to 4 in Table 3 deteriorated flange formability due to insufficient self-recrystallization.
[0037]
【The invention's effect】
As described above, according to the method of the present invention, it is possible to produce a steel plate for a can excellent in workability such as ridging resistance and stretch flangeability in a low-cost production process without annealing.
Further, according to the method of the present invention, since the material uniformity is improved and the yield is improved in this process-saving process, a steel plate for cans with stable quality can be produced at a lower cost.

Claims (10)

C: 0.0030 wt% or less, Si: 0.02 wt% or less, Mn: 0.05 to 0.5 wt%, P: 0.02 wt% or less, S: 0.02 wt% or less, solAl: 0.1 wt% or less , N: 0.0030 wt% or less, with the balance being roughly rolled a steel slab composed of Fe and inevitable impurities, joining the obtained sheet bar with the preceding sheet bar, and then finishing temperature Ar ₃ Finish rolling so as to be −50 ° C. or more, winding in a temperature range of 640 to 750 ° C., removing the scale, and cold rolling at a rolling reduction of 40 to 90%, and then 200 to 300 ° C. for 5 seconds. The manufacturing method of the steel plate for cans which did the recrystallization annealing after the cold rolling characterized by performing the above heat retention heat processing. C: 0.0030 wt% or less, Si: 0.02 wt% or less, Mn: 0.05 to 0.5 wt%, P: 0.02 wt% or less, S: 0.02 wt% or less, solAl: 0.1 wt% or less , N: 0.0030 wt% or less, with the balance being roughly rolled a steel slab composed of Fe and inevitable impurities, joining the obtained sheet bar with the preceding sheet bar, and then finishing temperature Ar ₃ After finishing rolling under lubrication so as to be less than −50 ° C., winding and self-annealing in a temperature range of 600 to 750 ° C., removing the scale, and cold rolling at a rolling reduction of 40 to 90%, The manufacturing method of the steel plate for cans which omitted the recrystallization annealing after the cold rolling characterized by performing the heat retention heat processing for 5 second or more at 200-300 degreeC. C: 0.0030 wt% or less, Si: 0.02 wt% or less, Mn: 0.05 to 0.5 wt%, P: 0.02 wt% or less, S: 0.02 wt% or less, solAl: 0.1 wt% or less N: 0.0030 wt% or less, Nb: 0.002 to 0.02 wt%, Ti: 0.001 to 0.02 wt%, or one or two of them, the balance being Fe and inevitable impurities The steel slab having the composition is roughly rolled, the obtained sheet bar is joined to the preceding sheet bar, and then finish rolling is performed so that the end temperature is Ar ₃ −50 ° C. or higher. Recrystallization after cold rolling, characterized by winding in temperature range, removing scale, cold rolling at a rolling reduction of 40 to 90%, and then performing heat holding heat treatment at 200 to 300 ° C. for 5 seconds or more Steel for cans without annealing The method of production. C: 0.0030 wt% or less, Si: 0.02 wt% or less, Mn: 0.05 to 0.5 wt%, P: 0.02 wt% or less, S: 0.02 wt% or less, solAl: 0.1 wt% or less N: 0.0030 wt% or less, Nb: 0.002 to 0.02 wt%, Ti: 0.001 to 0.02 wt%, or one or two of them, the balance being Fe and inevitable impurities The steel slab having the composition is roughly rolled, the obtained sheet bar is joined with the preceding sheet bar, and then finish rolling is performed under lubrication so that the end temperature is less than Ar ₃ -50 ° C. Winding self-annealing in a temperature range of ˜750 ° C. After scale removal, after cold rolling at a rolling reduction of 40 to 90%, a heat holding heat treatment at 200 to 300 ° C. for 5 seconds or more is performed. recrystallization after cold rolling Method of manufacturing a steel sheet for cans you omit the annealing. C: 0.0030 wt% or less, Si: 0.02 wt% or less, Mn: 0.05 to 0.5 wt%, P: 0.02 wt% or less, S: 0.02 wt% or less, solAl: 0.1 wt% or less , N: 0.0030 wt% or less, with the balance being roughly rolled a steel slab composed of Fe and inevitable impurities, joining the obtained sheet bar with the preceding sheet bar, and then finishing temperature Ar ₃ Finish rolling so as to be −50 ° C. or higher, winding in a temperature range of 640 to 750 ° C., removing the scale, cold rolling at a rolling reduction of 40 to 90%, performing surface treatment, The manufacturing method of the steel plate for cans which omitted the recrystallization annealing after the cold rolling characterized by performing the heat retention heat processing for 5 second or more at 200-300 degreeC. C: 0.0030 wt% or less, Si: 0.02 wt% or less, Mn: 0.05 to 0.5 wt%, P: 0.02 wt% or less, S: 0.02 wt% or less, solAl: 0.1 wt% or less , N: 0.0030 wt% or less, with the balance being roughly rolled a steel slab composed of Fe and inevitable impurities, joining the obtained sheet bar with the preceding sheet bar, and then finishing temperature Ar ₃ After finishing rolling under lubrication so as to be less than −50 ° C., winding and self-annealing in a temperature range of 600 to 750 ° C., removing the scale, and cold rolling at a rolling reduction of 40 to 90%, A method for producing a steel plate for cans, wherein surface treatment is performed, followed by heat-holding heat treatment at 200 to 300 ° C. for 5 seconds or more, wherein recrystallization annealing after cold rolling is omitted. C: 0.0030 wt% or less, Si: 0.02 wt% or less, Mn: 0.05 to 0.5 wt%, P: 0.02 wt% or less, S: 0.02 wt% or less, solAl: 0.1 wt% or less N: 0.0030 wt% or less, Nb: 0.002 to 0.02 wt%, Ti: 0.001 to 0.02 wt%, or one or two of them, the balance being Fe and inevitable impurities The steel slab having the composition is roughly rolled, the obtained sheet bar is joined to the preceding sheet bar, and then finish rolling is performed so that the end temperature is Ar ₃ −50 ° C. or higher. Winding in the temperature range, removing the scale, cold rolling at a rolling reduction of 40 to 90%, performing a surface treatment, and then performing a heat holding heat treatment at 200 to 300 ° C. for 5 seconds or more. re after cold rolling Method of manufacturing a steel sheet for cans you omit the crystal annealing. C: 0.0030 wt% or less, Si: 0.02 wt% or less, Mn: 0.05 to 0.5 wt%, P: 0.02 wt% or less, S: 0.02 wt% or less, solAl: 0.1 wt% or less N: 0.0030 wt% or less, Nb: 0.002 to 0.02 wt%, Ti: 0.001 to 0.02 wt%, or one or two of them, the balance being Fe and inevitable impurities The steel slab having the composition is roughly rolled, the obtained sheet bar is joined with the preceding sheet bar, and then finish rolling is performed under lubrication so that the end temperature is less than Ar ₃ -50 ° C. Winding self-annealing in a temperature range of ˜750 ° C. After removing the scale, after cold rolling at a rolling reduction of 40 to 90%, surface treatment is performed, and then heat holding heat treatment at 200 to 300 ° C. for 5 seconds or more Specially applied Cold preparation method for the omitted steel sheet for cans recrystallization annealing after rolling to. The method for producing a steel plate for cans according to any one of claims 5 to 8, wherein the surface treatment is any one of tin plating, chromium plating, chemical conversion treatment and oil coating. The method for producing a steel plate for a can according to any one of claims 1 to 9, wherein the speed of the finish rolling is 1000 m / min or more at the exit side speed of the final stage, and the speed fluctuation amount is 10% or less.