JP5076544B2 - Manufacturing method of steel sheet for cans - Google Patents

Description

  The present invention relates to a method for producing a steel plate for a can used for a two-piece DRD can or a three-piece welded can used as a can for beverage cans or food cans.

In recent years, in order to expand the demand for steel cans as steel plates for cans, reduction of can manufacturing costs has been taken.
As a measure to reduce can manufacturing costs, the cost of materials can be reduced, and not only two-piece cans that are drawn, but also three-piece cans mainly made of simple cylindrical molding, the use of thinner steel sheets can be achieved. It is being advanced.
However, simply reducing the thickness of the steel sheet reduces the strength of the can body, so it is not possible to use a thinned steel sheet in places where high-strength materials such as DRD cans and can bodies of welded cans are used, A high strength and extremely thin steel plate for cans has been desired. For example, when using a steel plate having a thickness of 0.16 mm, it is necessary to use a high strength material having a Rockwell hardness of about 73 to 76 and a tensile strength of about 550 MPa to 620 MPa at least for the can body.
Currently, ultra-thin and hard steel plates for cans are manufactured by the Duble Reduce method (hereinafter referred to as DR method) in which secondary cold rolling is performed after annealing. However, since the DR method has one more process than the processes up to hot rolling, cold rolling, annealing, secondary cold rolling and normal annealing, the cost is increased accordingly. Therefore, in this type of steel sheet for can manufacturing, cost reduction is demanded, and a method for manufacturing up to the recrystallization annealing process by adding various reinforcing elements has been proposed.
For example, Patent Document 1 and Patent Document 2 provide a steel sheet characterized by a high r value and small anisotropy by performing recrystallization annealing. Such a steel plate having a small anisotropy is suitable for a drawn can or the like that should suppress the occurrence of ears as much as possible.

However, a steel sheet that does not require a small amount of anisotropy does not necessarily need to be recrystallized after cold rolling. Recrystallization annealing is a method of heat treatment at a low temperature so that the strain that has been introduced in the cold rolling process after the strength is increased by cold rolling and the ductility of the material is restored to the minimum necessary range. Applicable on behalf of In this method, since recrystallization annealing is not performed, it is not necessary to add an element having precipitation strengthening ability or solid solution strengthening ability, and there is no need to worry about the influence of such elements on the corrosion resistance. Therefore, for steel sheets that do not require small anisotropy, the method of performing recovery annealing is effective, and the following techniques have been proposed.
In Patent Document 3, after performing finish rolling below the Ar3 transformation point, performing high temperature winding, and performing cold rolling at a rolling reduction of 85 to 90% by setting the crystal grain size after hot rolling to 50 μm Discloses a technique for obtaining a steel sheet having a TS of 530 to 570 MPa and an El of 6 to 8% by performing continuous annealing at 450 to 580 ° C.
In Patent Document 4, YS is obtained by performing finish rolling below the Ar3 transformation point at the time of hot rolling, performing cold rolling at a reduction rate of 85% or less, and then heat-treating at 200 to 500 ° C. for 10 minutes. A technique for obtaining a 640 MPa steel sheet is disclosed.
Patent Document 5 discloses a technique for obtaining a Rockwell hardness (HR30T) of about 70 by performing cold rolling and annealing at 400 ° C. or higher and a recrystallization temperature or lower.
In Patent Document 6, the steel having the same composition as Patent Document 5 is hot-rolled at least 50% at a temperature below the Ar3 transformation point, cold-rolled at a reduction ratio of 50% or more, and then 400 ° C or more. A technique for obtaining a steel having a Rockwell hardness of about 65 by annealing at a recrystallization temperature or lower is disclosed. Here, the recrystallization temperature refers to a temperature at which the recrystallization rate becomes a structure of less than 10%.
In Patent Document 7, finish rolling is performed at 40% or more of the total rolling reduction below the Ar3 transformation point during hot rolling, and cold rolling is performed at a rolling reduction of 50% or more, and then annealing is performed in a short time of 350 to 650 ° C. By doing so, YS discloses a technology for obtaining steel of 540 MPa to 700 MPa.
JP 2001-107186 JP 2005-336610 A Japanese Patent Laid-Open No. 53-20445 JP-A-8-269568 JP-A-6-248338 JP-A-6-248339 JP-A-8-41549

However, the above prior art has the following problems.
For example, in Patent Document 3, Patent Document 4, Patent Document 6, and Patent Document 7, it is necessary to perform finish rolling below the Ar3 transformation point during hot rolling. Certainly, when finish rolling below the Ar3 transformation point, the ferrite grain size of the hot-rolled material increases, and the strength of the steel after hot rolling decreases as shown in Fig. 3 shown in Patent Document 3, It is effective as a method for reducing the strength of steel itself. However, the edge part, which has a faster cooling rate than the center part, tends to have a lower temperature during finish rolling, and the strain introduced during finish rolling tends to increase the strength of the edge part without being released by recrystallization or recovery. is there. For this reason, the difference in strength between the center portion and the edge portion becomes large, and it is difficult to obtain a uniform hot-rolled sheet in the width direction, so it is difficult to obtain a uniform one in the current operation.
In Patent Document 4, steel having a YS of 640 to 680 MPa is obtained by annealing at 200 to 500 ° C. for 10 minutes or more after the cold pressure and taking the strain. However, if annealing is performed for 10 minutes or longer in a continuous annealing furnace, the line speed must be lowered, and productivity is significantly reduced.
Patent Document 5 and Patent Document 6 are characterized by annealing at 400 ° C. or higher and below the recrystallization temperature, but the strength of the steel obtained is about 65 to 70 in Rockwell hardness, which is the object of the present invention. In order to obtain a steel with a strength level, it is necessary to lower the annealing temperature. Therefore, since it cannot obtain at the annealing temperature manufactured with the normal can material, it is necessary to provide an annealing cycle separately, and productivity falls.
This invention is made | formed in view of this situation, and it aims at solving the above-mentioned problem of the prior art and proposing the method of manufacturing the steel plate for cans with high intensity | strength.
That is, the present invention is applied to applications where small anisotropy is not required, such as welding cans, and is intended for steel plates for cans that require workability in addition to strength. It aims at proposing the method of manufacturing the steel plate for high intensity | strength cans, ensuring required ductility.

The inventors of the present invention have intensively studied to solve the above problems. As a result, the following knowledge was obtained.
On the premise that the target strength is obtained by reducing the strength by recovery annealing, optimization of the component composition and manufacturing conditions was studied. And among them, by performing finish rolling above the Ar3 transformation point, a uniform hot-rolled steel sheet in the width direction with no difference in strength between the center part and the edge part is obtained, and after cold rolling, a recrystallization start temperature of −200 ° C. As described above, annealing at a recrystallization start temperature of −20 ° C. and lowering to a target strength level in a so-called recovery stage, and making these two features of the present invention and making them the main requirements, the target characteristics can be obtained. I found out.
Furthermore, by adding Nb: 0.005-0.05% and B: 0.0005-0.005%, annealing in the same temperature range (500-700 ° C) as the annealing temperature currently produced with steel plates for cans under the above production conditions It was also possible to obtain a tensile strength of 550 MPa to 650 MPa.

The present invention has been made based on the above findings, and the gist thereof is as follows.
[1] By mass%, C: 0.003% or less, N: 0.004% or less, Mn: 0.05% to 0.5% or less, P: 0.02% or less, Si: 0.02% or less, S: 0.03% or less, Al: 0.1% The steel containing the following, with the balance being iron and inevitable impurities, is hot-rolled at a finishing temperature equal to or higher than the Ar ₃ transformation point, wound at a winding temperature of 600 to 750 ° C., pickled, and then pickled. After performing cold rolling at a reduction rate of ~ 95%, annealing is performed at a temperature of (recrystallization start temperature −200) to (recrystallization start temperature −20) ° C. A method for producing a steel plate for a can.
[2] For cans according to [1], wherein the steel further contains one or two of mass%, Nb: 0.001% to 0.05%, and B: 0.0001% to 0.005%. A method of manufacturing a steel sheet.

In the present specification, “%” indicating the component of steel is “% by mass”.
In the present invention, the recrystallization start temperature is a temperature at which the rate of change in strength greatly varies with temperature, as shown in FIG. 1, and a structure in which the recrystallized structure accounts for 5% of the entire structure is obtained. Temperature.

According to the present invention, a steel plate for cans having a tensile strength of 550 to 600 MPa and a total elongation of 5% or more is obtained. Even in a method in which the DR and recrystallization annealing steps are omitted, when Nb and B are added, a tensile strength of 550 to 650 MPa and an elongation of 4% or more can be obtained.
As a result, by applying the production method of the present invention, it is possible to produce and provide a high-strength steel sheet for cans at a low cost without impairing corrosion resistance for can applications that do not require small anisotropy. become.
Furthermore, since the manufacturing method of this invention anneals in a low temperature range compared with the manufacturing method of the normal steel plate for cans, it becomes possible to reduce energy cost. Further, by adding Nb and B, annealing can be performed in the same temperature range as a normal steel plate for cans. In this case, it is not necessary to separately provide an annealing chance. As a result, it becomes possible to manufacture a TS550-6500 MPa grade steel sheet without impeding productivity.

  Furthermore, in the present invention, since the annealing is performed in a temperature range in which the change in strength is small depending on the annealing temperature, a steel plate having a uniform strength level in the width direction can be obtained even if the annealing temperature varies.

Hereinafter, the present invention will be described in detail.
The steel plate for cans of the present invention is a steel plate for cans having a tensile strength (hereinafter sometimes referred to as TS) of 550 to 600 MPa and a total elongation of 5% or more. Or when adding Nb and B, it is a steel plate for cans having a tensile strength of 550 to 650 MPa and a total elongation of 4% or more. Then, in manufacturing the steel sheet for the can is hot rolled at a finishing temperature of more than Ar ₃ transformation point, performing annealing in (recrystallization starting temperature -200) - (recrystallization starting temperature -20) ° C. of temperature It is characterized by that. These are the most important requirements of the present invention.

Next, the component composition of the steel plate for cans of this invention is demonstrated.
C: 0.003% or less Since the steel plate for cans proposed in the present invention increases the strength by the strain introduced by the primary cold rolling, it is necessary to reduce the alloy elements that increase the strength as much as possible. Regarding the ductility, the local ductility required at the time of can molding cannot be sufficiently obtained. In addition, if the amount of residual solute carbon increases, cracks will occur during stretch flange molding of the tightened part, which is the final process of can manufacturing, and wrinkles will occur when performing neck processing and flange processing because the amount of work hardening will also increase. There is a risk of doing. From the above, the C content is 0.003% or less.

N: 0.004% or less
N is an impurity element inevitably mixed in the steel. When the amount of N increases, slab cracking is likely to occur in the straightening zone during continuous casting. In addition, precipitates are formed to reduce the elongation, and when remaining in a solid solution state, the steel is hardened. As a condition for preventing the above contents, N is 0.004% or less. For applications that require further workability, 0.002% or less is preferable.

Si: 0.02% or less
Si is an element that increases the strength of steel by solid solution strengthening, but if added in a large amount, corrosion resistance is significantly impaired. Therefore, 0.02% or less.

Mn: 0.05% to 0.3%
Mn increases the strength of the steel by solid solution strengthening and reduces the crystal grain size. In addition, it is an element that increases the strength even as it is refined. The upper limit of Mn is 0.3% so as not to cause the above characteristics. On the other hand, if the Mn content is less than 0.05%, it is difficult to avoid so-called hot brittleness even when the S content is reduced, and problems such as surface cracks occur during hot rolling. Therefore, the lower limit of Mn is 0.05%.

P: 0.02% or less
If the P content is large, the strength of the steel will be remarkably increased by solid solution strengthening and the corrosion resistance will be deteriorated.

S: 0.03% or less
S is present as an inclusion in steel, and is an element that is disadvantageous to the ductility and corrosion resistance of the steel sheet, so 0.03% or less.

Al: 0.1% or less
Al improves the cleanliness as a deoxidizer. Moreover, it combines with solid solution N to form AlN and has an effect of reducing the amount of solid solution N. Therefore, it is necessary to contain in steel to some extent. As the condition, it is desirable to add approximately 0.005% or more. On the other hand, when the Al content exceeds 0.1%, the effect of improving the cleanliness is saturated, and problems such as an increase in manufacturing cost and an increase in the tendency to generate surface defects occur. Therefore, 0.1% or less.

Nb: 0.001 ~ 0.05%
Nb is an element having a high carbide-forming ability, and the recrystallization temperature rises due to pinning of grain boundaries by the generated carbide. Therefore, by changing the amount of Nb added, it is possible to change the recrystallization temperature of the steel and perform annealing at the target temperature as needed. And it can also combine the opportunity of annealing with other steel plates, which is very efficient from the viewpoint of productivity. However, if the content exceeds 0.05%, the recrystallization temperature becomes too high, the CAL threadability is lowered, and the target strength is increased due to precipitation strengthening of carbides, so the Nb content is 0.05% or less. . Basically, in the present invention, an element that increases the strength of the steel sheet is not added, but Nb needs to be added from the viewpoint of the annealing temperature, and if it is 0.05% or less, the precipitation of Nb is rather adjusted by adjusting the addition amount. It is possible to use reinforcement to achieve the desired strength. Further, the addition of Nb is also effective in preventing a decrease in welding strength by suppressing recrystallization during welding. On the other hand, if the Nb addition amount is less than 0.001%, the above effect cannot be exhibited, so 0.001% is set as the lower limit.

B: 0.0005-0.005% or less
B is an element that raises the recrystallization temperature. Therefore, B is added for the same reason as Nb addition. However, if added excessively, recrystallization in the austenite region must be inhibited during hot rolling and the rolling load must be increased, so the B addition amount is 0.005% or less. Moreover, since 0.005% or less cannot raise the recrystallization temperature, 0.0005% is made the lower limit.
Similarly to Nb, if B is within the above range, the desired strength can be obtained by precipitation strengthening of B. It is also effective to prevent the welding strength from being lowered by suppressing recrystallization during welding.

  The balance is Fe and inevitable impurities.

Plate thickness: 0.18 mm or less In the present invention, the plate thickness is an important factor. It is effective that the tensile strength of 550 MPa or more, which is the object of the present invention, is in a range where the plate thickness is 0.18 mm or less. In addition, if the steel sheet has a thickness of more than 0.18 mm, continuous annealing can be easily performed even in a high temperature range exceeding 750 ° C., but if the steel sheet has a thickness of 0.18 mm or less, the fracture or the shape of the plate may deteriorate during continuous annealing There is a decrease in productivity. Since the annealing temperature performed in the present invention is set to a recrystallization start temperature of −20 ° C. or less (the temperature described in the examples: 700 ° C. at the highest temperature), steel with a plate thickness of 0.18 mm or less can be easily produced. Therefore, in the present invention, the plate thickness is limited to 0.18 mm or less in order to express the effect in the range of the tensile strength of 550 MPa or more and to express the productivity improvement effect by annealing in the low temperature region.

Tensile strength: 550-650MPa
The present invention contemplates application to a can body portion of a DRD can or a welded can that currently uses a high strength and extremely thin material such as a DR material. If steel with a plate thickness of 0.18 mm or less and a tensile strength of 550 MPa or less, the can strength is insufficient, and there is a concern about buckling of the can. To avoid this, the tensile strength is set to 550 MPa or more. On the other hand, when trying to obtain a strength exceeding 650 MPa, a large amount of element is required, which may impair the corrosion resistance.
The tensile strength is controlled to a target value by the component, the cold rolling rate, and the annealing temperature.
Specifically, C: 0.003% or less, N: 0.004% or less, Mn: 0.05% to 0.5% or less, P: 0.02% or less, Si: 0.02% or less, S: 0.03% or less, Al: 0.1% or less Addition to make the cold rolling rate 60% or more, and control the tensile strength to 550-600MPa by annealing at the soaking temperature at the temperature of recrystallization start temperature -200) ~ (recrystallization start temperature-20) ° C. To do.
On the other hand, C: 0.003% or less, N: 0.004% or less, Mn: 0.05% to 0.5% or less, P: 0.02% or less, Si: 0.02% or less, S: 0.03% or less, Al: 0.1% or less, Nb: 0.001 % To 0.05%, B: 0.0001% to 0.005% One or two kinds are added to make the cold rolling rate 60% or more, and the soaking temperature is the recrystallization start temperature −200) to (recrystallization start temperature −20 ) The tensile strength is controlled to 550 to 650 MPa by annealing at a temperature of ° C.

Total elongation: If the total elongation is 4% or more and less than 4%, the weldability of the weld can deteriorates and the cracking rate increases, which affects the workability. To avoid this, the total elongation was limited to 4% or more. In order to improve the workability as much as possible, it is desirable to secure a total elongation of 5% or more.

  Note that the total elongation is controlled to a target value based on the components and the cooling rate after finishing during hot rolling.

Next, the manufacturing method of the steel plate for cans of this invention is demonstrated.
The molten steel adjusted to the above-described chemical composition is melted by a generally known melting method using a converter or the like, and then made into a rolled material by a commonly used casting method such as a continuous casting method.
Next, it is set as a hot-rolled sheet by hot rolling using the rolling raw material obtained by the above. At the start of rolling, the rolled material is preferably 1250 ° C. or higher. The finishing temperature is not less than the Ar3 transformation point. Then, it winds at the coiling temperature of 600-750 degreeC. Next, after pickling and cold rolling at a rolling reduction of 60 to 95%, annealing is performed at a temperature of (recrystallization start temperature −200) to (recrystallization start temperature −20) ° C.
(1) Hot rolling conditions Finishing temperature: Ar3 transformation point or higher It is necessary to finish so that the hot rolling finishing temperature is higher than the Ar3 transformation point. When finish rolling is performed below the Ar3 transformation point, the grain size of the hot-rolled structure increases, and the strength of the steel after hot-rolling is reduced, so that the strength after cold-rolling is likely to be reduced. It is effective for the method. However, if finish rolling is performed so that the center part of the slab is less than the Ar3 transformation point, the edge part that has a faster cooling rate than the center part does not consume the strain introduced during finish rolling due to recrystallization or recovery. Becomes hard, and the difference in strength between the central portion and the edge portion increases, and a hot-rolled sheet having a non-uniform structure is easily obtained. Therefore, in order to obtain a hot-rolled sheet having a uniform structure, the finishing temperature is set to the Ar3 transformation point or higher.
(2) Winding temperature: 600 ℃ ~ 750 ℃
The coiling temperature for hot rolling needs to be 600 ° C or higher and 750 ° C or lower. If it is less than 600 ° C., the heat retention effect after winding is not sufficient, and the ferrite grain size of the hot-rolled sheet becomes small, so the strength tends to increase, and it becomes easy to make a mixed grain structure, which is not preferable. . On the other hand, when it winds up at the temperature exceeding 750 degreeC, the scale thickness of a steel plate increases notably and there exists a possibility that the descaling property at the time of pickling of the next process may deteriorate. In order to further improve these problems, it is desirable to set the temperature at 700 ° C. or lower.
(3) Cold rolling conditions (rolling rate): 60-95%
In cold rolling, the rolling reduction is 60 to 95%. If the rolling reduction is less than 60%, the desired strength is not reached after cold rolling and heat treatment. Moreover, the malfunction considered to be based on the nonuniformity of a material, especially the nonuniformity of a plate | board thickness direction arises. On the other hand, if it exceeds 95%, it becomes difficult to avoid deterioration of local ductility.
(4) Heat treatment (annealing) conditions after cold rolling:
Temperature: Recrystallization start temperature −200 ° C. or higher, Recrystallization start temperature −20 ° C. or lower Heat treatment (annealing) is performed in a temperature range of a recrystallization start temperature −200 ° C. or higher and a recrystallization start temperature −20 ° C. or lower. Since the recrystallization temperature is changed by adding Nb, B, etc., the recrystallization start temperature of each steel is set to −200 ° C. to −20 ° C. The purpose of annealing in the present invention is to reduce the strength to the target strength by performing strain relief annealing from a state where the strength is increased by strain introduced by cold pressure. If the recrystallization start temperature is lower than −200 ° C., the strain is not sufficiently released, and the recrystallization start temperature −200 ° C. is set as the lower limit value because it is higher than the target strength and the ductility becomes lower. On the other hand, if the temperature is too high, recrystallization will start and it will soften too much to obtain the target strength, and it will not be able to obtain a uniform structure due to partial recrystallization. Is the upper limit.
In the present invention, it is considered to perform annealing in a continuous annealing furnace. Therefore, in order not to inhibit the productivity, it is preferable that the soaking time during annealing is 10 s or more and 90 s or less.

A steel slab was obtained by melting the steel containing the composition shown in Table 1 and the balance being inevitable impurities and Fe. After the obtained steel slab was reheated at 1250 ° C., hot rolling was performed at a finish rolling temperature of 800 to 890 ° C. and a winding temperature of 620 to 700 ° C. Next, after pickling, it was cold-rolled at a rolling reduction of 90% to produce a 0.15 mm thin steel plate. The obtained thin steel sheet is annealed in a continuous annealing furnace at an annealing temperature of 350 to 620 ° C. and an annealing time of 30 s (recovery), subjected to temper rolling so that the elongation rate is 1.5% or less, and ordinary chrome plating Was applied continuously to obtain tin-free steel. Detailed production conditions are shown in Table 2.
As for the annealing temperature, the recrystallization behavior of the steel sheet shown in Table 1 in FIG. 1 was confirmed. As a result, it was confirmed that the recrystallization was completed at 600 ° C. ˜580 ° C.

A tensile test and an r-value test were performed on the plated steel plate (tin-free steel) obtained as described above. The tensile test was performed using a JIS5 size tensile test piece, the tensile strength and elongation were measured, and the strength and ductility were evaluated. The r value was determined by the natural vibration method defined in JIS Z2254.
The obtained results are shown in Table 3.

From Table 3, the inventive examples (levels 1 and 2) have a tensile strength of 550 to 600 MPa and a total elongation of 5% or more.
On the other hand, in the comparative example (level 3), the annealing temperature is lower than the range of the present invention, and the ductility is reduced because the recovery of strain in steel is small. Further, the comparative example (level 4) is insufficient in strength because the annealing temperature exceeds the range of the present invention and recrystallization starts locally.

A steel slab was obtained by melting the steel containing the composition shown in Table 4 and the balance of inevitable impurities and Fe in an actual converter. The obtained steel slab was reheated at 1150 to 1250 ° C., and then hot rolled at a finish rolling temperature of 890 ° C. and a winding temperature of 620 ° C. Next, after pickling, the steel sheet was cold-rolled at a rolling reduction of 80 to 90% to produce a thin steel plate of 0.15 to 0.25 mm. The obtained thin steel sheet is annealed (recovery) at an annealing temperature of 300 to 700 ° C. and an annealing time of 30 s in a continuous annealing furnace, subjected to temper rolling so that the elongation rate is 1.5% or less, and ordinary chromium plating is performed. Was applied continuously to obtain tin-free steel. Detailed manufacturing conditions are shown in Table 5.
Moreover, regarding the annealing temperature, as a result of confirming the recrystallization behavior of the steel plates 2 to 6, it was confirmed that recrystallization was completed at 620 to 750 ° C. as shown in Table 5. For example, the result of confirming the recrystallization behavior of the steel plate 5 in Table 4 is shown in FIG.

  A tensile test and an r-value test were performed on the plated steel plate (tin-free steel) obtained as described above. Each characteristic was measured by the same method as in Example 1. The results obtained are shown in Table 6.

From Table 6, the inventive examples (levels 5, 7, 9, 10, 12, 13) have a tensile strength of 550 to 650 MPa and a total elongation of 4% or more.
On the other hand, in the comparative examples (levels 6 and 8), the annealing temperature is lower than the range of the present invention and the recovery of strain in the steel is small, so the strength is high and the ductility is low. In the comparative example (level 11), the annealing temperature is higher than the range of the present invention, and the recrystallization starts locally, so that the strength is insufficient. Moreover, since a component exceeds the range of this invention in a comparative example (level 14), intensity | strength is high and ductility is falling.

  And in the steel plate obtained by this invention, since recrystallization behavior changes with Nb and B addition amount, it is possible to change the applicable annealing temperature. Moreover, it is possible to change the intensity | strength obtained by Nb and B addition amount. Therefore, the manufacturing method of the present invention can be annealed in the same cycle as other steel plates for cans, and can obtain a desired strength. Therefore, the manufacturing method is very efficient in manufacturing an actual machine.

  According to the present invention, a steel plate for a can having a tensile strength of 550 to 650 MPa and an elongation of 4% or more can be obtained even if the DR and recrystallization annealing steps are omitted without adversely affecting ductility and corrosion resistance. Therefore, the steel plate for cans produced by the production method of the present invention is most suitable as a steel plate for cans, mainly 2-piece DRD cans and 3-piece welded cans used as cans for beverage cans and food cans.

It is a figure which shows the relationship between annealing temperature, TS, and recrystallization rate. It is a figure which shows the relationship between annealing temperature, TS, and recrystallization rate.

Claims (2)

In mass%, C: 0.003% or less, N: 0.004% or less, Mn: 0.05% to 0.5% or less, P: 0.02% or less, Si: 0.02% or less, S: 0.03% or less, Al: 0.1% or less Steel with the balance being iron and inevitable impurities,
Hot rolling at a finishing temperature above the Ar ₃ transformation point,
Winding at picking temperature of 600-750 ° C, pickling,
Then, after performing cold rolling at a rolling reduction of 60 to 95%,
A method for producing a steel plate for cans having a plate thickness of 0.18 mm or less, wherein annealing is performed at a temperature of (recrystallization start temperature −200) to (recrystallization start temperature −20) ° C.   The steel sheet for cans according to claim 1, wherein the steel further contains one or two kinds of Nb: 0.001% to 0.05% and B: 0.0001% to 0.005% in mass%. Method.

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