JP5434212B2 - Steel plate for high-strength container and manufacturing method thereof - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a steel plate for a high-strength container suitable as a container material for performing diameter reduction or enlargement processing after three-piece processing such as welding or two-piece processing such as DI, and a manufacturing method thereof.

2. Description of the Related Art In recent years, product development for reducing the product thickness of a steel material (steel plate), which is a material, has been promoted for the purpose of reducing costs and reducing the use of materials and the environmental load.
Further, since the rigidity is reduced when the product plate thickness is reduced, it is necessary to increase the strength of the steel material in order to compensate for this reduction in rigidity. However, when the strength of the steel material is increased, the steel material is hardened, so that there is a problem that cracking occurs in flange processing or necking processing.
In contrast, various manufacturing methods have been devised.

For example, in Patent Document 1, after controlling the components in steel within a certain range, hot rolling is finished at (Ar3 transformation point −30 ° C.) or more, and then pickling and cold rolling are performed. A method of carrying out continuous annealing and secondary cold rolling has been proposed.
However, in the method of Patent Document 1, P is set to 0.02 wt% or less so as not to deteriorate the flange workability, neck workability, and corrosion resistance, and further, the reduction ratio of the secondary cold rolling is set to 15 to 30%, so that it is a thin product. However, it is difficult to process efficiently and difficult to produce, and appearance defects are likely to occur. Furthermore, there is a problem that cracks may occur on the surface layer of the slab, resulting in a decrease in yield of the product. Moreover, it is difficult to produce stably, and improvement is required.

Moreover, the following method is proposed as a typical manufacturing method of the hard steel plate for containers, and it selects and uses suitably according to the kind of annealing (for example, nonpatent literature 1).
Hot rolling->pickling-> cold rolling-> box annealing (BAF)-> second cold rolling (rolling ratio: 20-50%)
Hot rolling->pickling-> cold rolling-> continuous annealing (CAL)-> second cold rolling (rolling ratio: 20-50%)
However, in the above method, various rolling oils with high viscosity are used for the purpose of improving lubricity during rolling, and therefore there is a problem of poor appearance after rolling due to uneven concentration of the rolling oil or partial oil adhesion. Further, when the rolling reduction ratio is high, the steel sheet is stretched by rolling, so that the difference in yield strength between the width direction of the steel sheet and the rolling direction becomes large.
On the other hand, a method of keeping the rolling reduction in the second cold rolling low can be considered. However, when the rolling reduction is lowered, it becomes difficult to obtain the required yield strength.

Japanese Patent No. 3108615

“Technological History of Steel Sheets for Cans in Japan” Issued on October 30, 1998, Japan Iron and Steel Institute p.188

  Thus, when it is going to obtain the steel plate for containers with thin product board thickness, there is no manufacturing method which satisfies all intensity | strength, workability, and productivity, and the present condition is desired.

  The present invention has been made in view of such circumstances, and has a tensile strength TS of 500 MPa or more, a proof stress difference between a sheet width direction and a rolling direction of 20 MPa or less, and further excellent for workability. It aims at providing a steel plate and its manufacturing method.

  The inventors of the present invention have intensively studied to solve the above problems. As a result, the following knowledge was obtained.

Adjusting the P content as the component composition, increasing the strength by performing a second cold rolling with a rolling reduction of 20 to 50%, and precipitating the carbide uniformly by performing an overaging treatment during continuous annealing Thus, it has been found that by using this carbide as a site for dispersing stress during processing, there is little incompatibility in appearance, and a high-strength material can be secured with a small difference in yield strength between the width direction and the rolling direction. Furthermore, it has also been found that a steel plate for containers that is further excellent in workability can be obtained by defining the particle size, density, and ratio of the carbide.
As described above, in the present invention, high strength steel sheets for cans have been completed by managing the components based on the above findings.

The present invention has been made based on the above findings, and the gist thereof is as follows.
[1] By mass%, C: 0.01 to 0.05%, Si: 0.04% or less, Mn: 0.1 to 1.2%, S: 0.10% or less, Al: 0.001 to 0.100%, N: 0.10% or less, P: 0.0020 to A steel plate for a high-strength container containing 0.100%, the balance being Fe and inevitable impurities, a tensile strength TS of 500 MPa or more, and a proof stress difference between the plate width direction and the rolling direction of 20 MPa or less.
[2] By mass%, C: 0.01 to 0.05%, Si: 0.04% or less, Mn: 0.1 to 1.2%, S: 0.10% or less, Al: 0.001 to 0.100%, N: 0.10% or less, P: 0.0020 to A steel plate for a high-strength container containing 0.020%, the balance being Fe and inevitable impurities, a tensile strength TS of 500 MPa or more, and a proof stress difference between the plate width direction and the rolling direction of 20 MPa or less.
[3] By mass%, C: 0.01 to 0.05%, Si: 0.04% or less, Mn: 0.1 to 1.2%, S: 0.10% or less, Al: 0.001 to 0.100%, N: 0.10% or less, P: 0.0020 to A steel containing 0.100%, the balance being Fe and inevitable impurities, is hot-rolled at a finishing temperature: (Ar3 transformation temperature-30 ° C) or higher and a coiling temperature: 400-750 ° C, pickled and cooled A method for producing a steel plate for a high-strength container, comprising performing a continuous annealing including an overaging treatment after the hot rolling and then performing a second cold rolling at a rolling reduction of 20 to 50%.
[4] By mass%, C: 0.01 to 0.05%, Si: 0.04% or less, Mn: 0.1 to 1.2%, S: 0.10% or less, Al: 0.001 to 0.100%, N: 0.10% or less, P: 0.0020 to A steel containing 0.020%, the balance being Fe and inevitable impurities, hot-rolled at a finishing temperature: (Ar3 transformation point temperature -30) ° C or higher and a coiling temperature: 400-750 ° C, pickled and cooled A method for producing a steel plate for a high-strength container, comprising performing a continuous annealing including an overaging treatment after the hot rolling and then performing a second cold rolling at a rolling reduction of 20 to 50%.
In addition, in this specification,% which shows the component of steel is mass% altogether. In the present invention, the “high-strength steel plate for containers” is a steel plate for containers having a tensile strength TS (hereinafter sometimes simply referred to as TS) of 500 MPa or more.
Furthermore, the steel plate for high-strength containers of the present invention is intended for container materials and can materials. Regardless of the presence or absence of surface treatment, tin plating, nickel tin plating, chromium plating (so-called tin-free plating) or further organic coating is applied, and it can be applied to a wide range of applications.
Further, the thickness of the plate is not particularly limited, but from the viewpoint of obtaining the effect by making the most of the present invention, the plate thickness is preferably 0.30 mm or less, and more preferably 0.20 mm or less. Particularly preferred is 0.170 mm or less.

According to the present invention, for a high-strength container having a TS of 500 MPa or more, having a proof stress difference of 20 MPa or less in the sheet width direction and the rolling direction, and excellent in workability that does not cause cracking during flange processing or necking processing. A steel plate is obtained.
Further, in the present invention, the P content is adjusted and the reduction ratio in the second cold rolling is increased to 20 to 50% to increase the strength, and the appearance problem after rolling and the difference in yield strength between the width direction and the rolling direction are increased. The problem is solved.
Further, by setting the N component to less than 0.01%, which is a preferred range, it is possible to prevent slab cracking and suppress a decrease in yield in products.

Hereinafter, the present invention will be described in detail.
The steel plate for containers of the present invention is a steel plate for high-strength containers having a TS of 500 MPa or more and a proof stress difference between the plate width direction and the rolling direction of 20 MPa or less. In the present invention, the P content is adjusted, and the reduction rate in the second cold rolling (hereinafter sometimes referred to as secondary cold rolling) is set to 20 to 50%, thereby increasing the strength. It is possible to provide steel plates for containers.

The component composition of the steel plate for containers according to the present invention will be described.
C: 0.01-0.05%
If the C component is large, the steel sheet after the secondary cold rolling is hardened more than necessary, and canability and neck workability are deteriorated. In addition, it becomes an element that causes HAZ cracking during flange processing due to remarkable hardening of the weld. When C exceeds 0.05%, these effects become significant, so C is made 0.05% or less. On the other hand, if the C component becomes extremely low, it is necessary to perform secondary cold rolling at a high pressure ratio in order to maintain the strength of the container, so C is made 0.01% or more. It is preferably 0.02% or more and 0.04% or less, more preferably 0.02% or more and 0.03% or less.

Si: 0.04% or less
When a large amount of Si is added, surface properties and corrosion resistance deteriorate. Therefore, Si is set to 0.04% or less.

Mn: 0.1-1.2%
Mn is an element effective in preventing hot cracking due to S. And the effect which prevents a crack is acquired by adding according to the amount of S. It also has the effect of refining crystal grains. In order to exhibit these effects, it is necessary to add at least 0.1% of Mn. On the other hand, if added in a large amount, the corrosion resistance tends to deteriorate and the steel plate is hardened more than necessary, and the flange workability and neck workability are deteriorated. Therefore, the upper limit is set to 1.2%. It is preferable to set it to 0.35% or less.

P: 0.0020-0.100%
P is a component that hardens steel, and in the present invention, P contains a predetermined amount according to the required strength. If less than 0.0020%, a TS of 500 MPa or more cannot be obtained, so the content is made 0.0020% or more. On the other hand, including an excessive amount of P component more than necessary deteriorates the corrosion resistance. In addition, flange workability and neck workability are deteriorated. Since these become remarkable when it exceeds 0.100%, the upper limit is made 0.100%. A content of 0.0020 to 0.020% is preferable because higher strength can be obtained by an appropriate strength by adding P and an effect of secondary cold rolling described later.

S: 0.10% or less
S exists as an inclusion in steel, and is an element that decreases the ductility of the steel sheet and further deteriorates the corrosion resistance. Therefore, it is 0.10% or less. Preferably it is 0.030% or less.

Al: 0.001 to 0.100%
Al is an element necessary for deoxidation of steel. If the amount is less than 0.001%, deoxidation is insufficient, and the flange workability and neck workability are deteriorated due to inclusions. Therefore, it is 0.001% or more. On the other hand, Al combines with the N component to reduce the solid solution N, but if the solid solution N is excessively reduced, the required strength cannot be obtained. Therefore, it shall be 0.100% or less. It is preferable to set it as 0.035 to 0.075%.

N: 0.10% or less N is an element useful for increasing the strength without increasing the hardness of the weld. However, if the content is too large, the steel sheet is remarkably hardened, and the risk of generating cracking defects in the rolled material (slab) is significantly increased. On the contrary, the flange workability and neck workability are deteriorated. Therefore, N is set to 0.10% or less. It is preferably 0.05% or less. Further, from the viewpoint of preventing slab cracking, it is more preferably less than 0.01%. Even more preferably, it is 0.005% or less. Thus, by reducing N, slab cracks can be reduced, and slab maintenance is not required, and yield can be improved.

The balance is Fe and inevitable impurities.
The balance other than the above components is Fe and inevitable impurities. As an inevitable impurity, for example, Sn: 0.01% or less is acceptable.

  The steel plate for containers of the present invention has the above composition, TS of 500 MPa or more, and a proof stress difference between the plate width direction and the rolling direction of 20 MPa or less. By having TS of 500 MPa or more, the rigidity does not decrease even if the plate thickness is reduced. Furthermore, since the difference in proof stress between the plate width direction and the rolling direction is 20 MPa or less, no cracking occurs during flange processing or necking processing.

Next, the manufacturing method of the steel plate for high strength containers of this invention is demonstrated.
The molten steel having the above composition is melted by a generally known melting method using a converter or the like, and then rolled into a rolled material (slab) by a generally known casting method such as a continuous casting method. Subsequently, these rolled materials are used to form hot rolled sheets by hot rolling.
Slab extraction temperature: 1050-1300 ° C (preferred conditions)
When the slab extraction temperature is 1050 ° C. or higher, a sufficiently high hot rolling end temperature can be secured in the hot rolling of the next step. On the other hand, when the extraction temperature is 1300 ° C. or lower, the surface properties of the steel sheet are not finally deteriorated. Therefore, the slab extraction temperature is preferably 1050 ° C. or higher and 1300 ° C. or lower.

Finishing temperature (hot rolling end temperature): (Ar3 transformation point temperature -30) ° C. or higher Hot rolling end temperature is to improve the cold rolling property and product characteristics of the subsequent process.
(Ar3 transformation point -30) It is necessary to set the temperature to be equal to or higher. (Ar3 transformation point -30) If it is less than 30 ° C, the metal structure of the final product is coarsened, and rough skin is likely to occur during can making. In addition, when the hot rolling finish temperature becomes low, a ridging phenomenon occurs, and an appearance defect after the forming process tends to occur. Accordingly, the hot rolling end temperature is set to (Ar3 transformation point−30) ° C. or higher.

Winding temperature: 400-750 ° C
If the coiling temperature is too low, the shape of the hot-rolled sheet will deteriorate, and the pickling and cold rolling operations in the next process will be hindered. On the other hand, if it becomes too high, aluminum nitride precipitates at the stage of the hot-rolled base plate, and it becomes impossible to ensure sufficient solute N for strengthening. In addition, a structure in which carbide aggregates is formed in the hot-rolled mother board, and the effect of uniform precipitation of carbide due to overaging described later cannot be obtained. In addition, this adversely affects the corrosion resistance of the steel sheet. Furthermore, pickling performance deteriorates as the scale thickness generated on the steel sheet surface increases. In order to avoid these problems, it is necessary to keep the temperature below 750 ° C.

  The hot-rolled sheet thus manufactured is pickled and cold-rolled to obtain a cold-rolled sheet. For pickling, the surface scale may be removed with an acid such as hydrochloric acid or sulfuric acid according to a conventional method.

Reduction ratio in cold rolling (after pickling): 80% or more (preferred condition)
If the rolling reduction is less than 80%, sufficient fine graining of the structure may not be obtained after annealing, so 80% or more is preferable. In addition, in order to achieve sufficient refinement | miniaturization of the structure | tissue with the steel plate of a raw material like this invention, 85% or more of a rolling reduction is more preferable. On the other hand, the upper limit of the rolling reduction is not particularly required, and is appropriately set in consideration of the capability of the equipment row for hot rolling and cold rolling.

Annealing temperature: 800 ° C or lower recrystallization temperature (preferred conditions)
If the non-recrystallized structure remains in the steel sheet, it causes a formability defect and a poor appearance at the time of can making, and therefore it is necessary to perform a recrystallization process by continuous annealing. However, if the annealing temperature is excessively increased, defects such as heat buckles and plate breakage occur during continuous annealing. And the risk of deteriorating appearance characteristics due to abnormal crystal grain growth increases. Therefore, the annealing temperature is preferably performed in a recrystallization temperature range of 800 ° C. or lower.

  Further, it is not necessary to keep the temperature constant within this temperature range. A time equivalent to soaking from 5 to 60 seconds is sufficient for the stability of operation. A soaking time of 5 s or more is preferable because the precipitation of carbides that become sites for dispersing stress during processing is sufficient.

Overaging treatment It is necessary to carry out an overaging treatment in order to further uniformly disperse the carbides precipitated by the annealing and to make the stress dispersion sites effective. In the overaging treatment, after the annealing, it is preferably cooled to a temperature range of 300 to 500 ° C. at a cooling rate of 10 ° C./s or more and maintained at a temperature range of 300 to 500 ° C. for 5 s or more. By cooling at a cooling rate of 10 ° C./s or higher to a temperature range of 300 to 500 ° C., it becomes easy for carbides to precipitate, and when kept at a temperature range of 300 to 500 ° C. for 5 seconds or more, uniform precipitation of carbides can be ensured. it can. In addition, by performing such overaging treatment, the difference in yield strength between the sheet width direction and the rolling direction can be 20 MPa or less even if the second cold rolling shown below is performed at a reduction rate of 20 to 50%. It becomes possible. By performing the overaging treatment under such conditions, the density and ratio of carbides having a particle size of 1.5 μm or less and a particle size of more than 1.5 μm and 3.0 μm or less can be set within a preferable range described later.

Second cold rolling reduction: 20-50% (preferably 20-30%)
The second cold rolling after the continuous annealing (hereinafter also referred to as secondary cold rolling) is necessary to ensure the pressure resistance of the weld can, that is, the yield strength of the steel sheet. In particular, in consideration of the case where the P content of the present invention is used, it is necessary that the rolling reduction of secondary cold rolling is at least 20%. On the other hand, when the rolling reduction exceeds 50%, the material property anisotropy increases, and the difference in yield strength between the sheet width direction and the rolling (rolling) direction exceeds 20 MPa. Moreover, the flange workability and neck workability in the new plate cutting method (a plate cutting method in which the rolling direction of the steel plate is parallel to the axial direction of the can body) are significantly deteriorated. Further, the welding at the time of can making increases the amount of strain release, and the softening in the heat affected zone becomes significant, so that flange cracking is likely to occur. Therefore, 50% or less. Preferably, it is 20% or more and 30% or less, but may be appropriately selected according to the P content and the intended steel sheet strength. Specifically, when the P content is as high as more than 0.020% and 0.100% or less, a relatively low rolling reduction is preferable.

  In the present invention, after secondary cold rolling, a plated layer can be formed on the surface of the cold-rolled steel sheet (at least one side) to obtain a plated steel sheet. Any plating layer applied to the steel plate for containers can be applied to the plating layer formed on the surface. Examples of the plating layer include tin plating, chromium plating, nickel plating, and nickel / chromium plating. Moreover, there is no problem in applying a coating, an organic resin film, etc. after these plating treatments.

A steel containing the components shown in Table 1 and the balance being Fe and unavoidable impurities was melted in a converter and made into a slab by a continuous casting method. Subsequently, these slabs were hot rolled at a slab extraction temperature of 1200 ° C., a hot rolling finishing temperature of 900 ° C. and a coiling temperature of 650 ° C. to obtain hot rolled sheets having a finished thickness of 2.0 mm. After that, these hot-rolled sheets were descaled by pickling, and further cold-rolled with a reduction rate of 90% to obtain cold-rolled sheets with a finished thickness of 0.20 mm, then the soaking temperature was set to 750 ° C, and the soaking time was set. Continuous annealing to 10 to 30 s, overaging treatment and secondary cold rolling were performed to obtain a cold rolled steel sheet.
The overaging treatment conditions and the secondary cold rolling reduction ratio are as shown in Table 2 and Table 3.

The steel plate obtained as described above was subjected to structure observation by the following method, and the density and ratio of the carbide particle size were determined. Moreover, the following test was done and the characteristic was evaluated.
The cold-rolled steel sheet obtained as described above was embedded in a bakelite resin and the cross section was polished. Next, after the caustic solution was used, an immersion treatment was performed in the caustic solution at 80 ° C. for 60 seconds using a sodium picrate acid solution prepared by mixing picric acid and sodium hydroxide. Next, the carbides were observed with a 400 × optical microscope in three fields (a range of about 0.1375 mm × 0.1375 mm). In each field of view, the number of carbides having a particle size of 1.5 μm or less, a particle size of more than 1.5 μm and less than 3.0 μm, and more than 3.0 μm was determined visually, and the average value of the density and ratio of the three fields of view was determined. At this time, the particle diameter of the carbide is set to the minimum diameter. For example, when the carbide shape is rectangular or elliptical and the short diameter and the long diameter exist, the minimum diameter is set as the particle diameter in the present invention.
(I) Tensile test JIS 13-B tensile test specimens were sampled in the rolling (L) direction from the center in the width direction of these cold-rolled steel sheets and subjected to a tensile test at a strain rate crosshead speed of 10 mm / s. The tensile strength TS and the yield strength YS were measured. The tensile test was carried out within one day after commercialization. The reason why the tensile test piece is a JIS 13-B test piece is to reduce as much as possible the phenomenon of breaking outside the gauge.

(Ii) Yield difference between sheet width direction and rolling direction YS measured by the tensile test in (i) above, and YS measured in the same manner as (i) on a JIS 13-B tensile specimen taken in the sheet width direction. The difference was obtained.

(Iii) Necking workability These cold-rolled steel sheets were Sn-plated (Sn deposition amount 2.8 g / m ² per side) to obtain plated steel sheets. After drawing, printing, and transparent varnish finish on the surface of this plated steel sheet, the steel sheet was cup-drawn under the following conditions without using press oil, and deep-drawing was performed by applying redrawing twice. The rate of occurrence of neck wrinkles was investigated.
Deep drawing conditions Blank diameter: 200mmφ
Lubrication condition: No press oil used, 1st aperture ratio: 1.5
Aperture ratio of the second aperture: 1.2
Aperture ratio of third aperture: 1.2
Wrinkle holding pressure of 1st to 3rd aperture: Optimal condition Flange processing: Elongation 8%
Redrawing die shoulder radius: 0.45mm
Machining speed: 0.3m / s
(Iv) In the deep drawing of flange crack resistance (iii), the incidence of flange cracking was investigated.

(V) Appearance These cold-rolled steel sheets were visually observed, and portions judged to have different gloss and color tone were regarded as defective appearance. When an appearance defect was confirmed even at one location in the observed 100 m unit, this 100 m was regarded as an appearance defect portion, and 10000 m was observed to obtain an appearance defect rate.
(Vi) Slab cracking The condition of slab cracking was visually observed on the slab surface after continuous casting.
If even one crack was confirmed in the observed 1 m unit, this 1 m was regarded as a defective appearance portion, and 10 m was observed to obtain the appearance defect rate. The results obtained are shown together with the conditions and in Table 3.

From Table 2 and Table 3, No.8-10, 13-18, 26-28, 31-36 which are examples of this invention have sufficient intensity | strength, and the proof stress difference of a sheet width direction and a rolling direction is 20 Mpa or less. For example, the performance required for 3-piece processing is sufficiently achieved. In addition, the appearance is excellent, and the comparative example No. It is recognized that there are few neck wrinkles and flange cracks compared to 1-7, 11, 12, 19-25, 29, 30. Moreover, in No.8-10, 13-15, 26-28, 31-33 whose density and ratio of a carbide | carbonized_material are a suitable range, it turns out that workability is still more excellent.
On the other hand, the comparative example No. Nos. 1, 2, 19 and 20 have a low rolling reduction in secondary cold rolling and cannot provide strength. No. In 3-5 and 21-23, the rolling reduction of secondary cold rolling is 20% or more and the strength is high, but the proof stress difference between the L direction and the C direction exceeds 20 MPa, and the occurrence of neck wrinkles and flange cracks is remarkable. It is. Moreover, the appearance defect has also occurred.
In addition, No. 6, 7, 11, 12, 24, 25, 29, 30 with a rolling reduction of secondary cold rolling of less than 20% cannot obtain strength.

Furthermore, the following knowledge was acquired regarding the density and ratio of carbide. In the steel plate for a high-strength container of the present invention, the ratio of the number of carbides having a particle size of 3.0 μm or less to the total number of carbides is preferably 85% or more from the viewpoint of workability. Furthermore, the ratio of the number of carbides having a particle size of 1.5 μm or less to the total number of carbides is preferably 52% or more. More preferably, the density of carbides with a particle size of 1.5 μm or less is 100/10000 μm ² or more, and the density of carbides with a particle size of more than 1.5 μm and 3.0 μm or less is 63/10000 μm ² .

  By setting the ratio of the number of carbides having a particle size of 3.0 μm or less to the total number of carbides to be 85% or more, a sufficient amount of carbides functioning as stress dispersion sites at the time of processing can be secured, and workability is further improved. More preferably, the ratio of the number of carbides having a particle size of 3.0 μm or less to the total number of carbides is more than 85%, and more preferably 90% or more.

  Further, when the ratio of the number of carbides having a particle size of 1.5 μm or less to the total number of carbides is 52% or more, the effect of the carbide functioning as a stress dispersion site is further enhanced, and the workability is further improved. More preferably, the ratio of the number of carbides having a particle size of 1.5 μm or less to the total number of carbides is more than 52%, and more preferably 55% or more.

Furthermore, the density of carbides with a particle size of 1.5 μm or less is 100/10000 μm ² or more, and the density of carbides with a particle size of more than 1.5 μm and 3.0 μm or less is 63/10000 μm ² , so that Increases workability. In More preferably, the density of the particle size 1.5μm or less of carbides 102 pieces / 10000 ² greater, more 105 pieces / 10000 ² or more, the density of the particle size 1.5μm ultra 3.0μm following carbide 70/10000 ² or more is there.

  The density and proportion of the carbide can be controlled by annealing the cold-rolled steel sheet under predetermined conditions. Specifically, in the continuous annealing process after cold rolling, an overaging treatment is performed by adjusting the thermal history of the steel sheet within a predetermined range.

  Further, Table 3 shows examples in which the N content is 0.0065% and 0.0043%, and the preferable range is less than 0.01%. From Table 3, it can be seen that when the N content is less than 0.01%, no slab cracking is confirmed and slab cracking is prevented.

  The steel plate for containers according to the present invention can provide excellent strength without cracking in necking and flange processing, so that, for example, food containers such as cans, non-food containers such as oil filters, and electronic parts such as batteries are mainly used. It can be suitably used as a container material.

Claims (4)

  By mass%, C: 0.01 to 0.05%, Si: 0.04% or less, Mn: 0.1 to 1.2%, S: 0.10% or less, Al: 0.001 to 0.100%, N: 0.10% or less, P: 0.0020 to 0.100% A steel plate for a high-strength container which contains, the balance is made of Fe and inevitable impurities, the tensile strength TS is 500 MPa or more, and the proof stress difference between the plate width direction and the rolling direction is 20 MPa or less.   By mass%, C: 0.01 to 0.05%, Si: 0.04% or less, Mn: 0.1 to 1.2%, S: 0.10% or less, Al: 0.001 to 0.100%, N: 0.10% or less, P: 0.0020 to 0.020% A steel plate for a high-strength container which contains, the balance is made of Fe and inevitable impurities, the tensile strength TS is 500 MPa or more, and the proof stress difference between the plate width direction and the rolling direction is 20 MPa or less. In mass%, C: 0.01 to 0.05%, Si: 0.04% or less, Mn: 0.1 to 1.2%, S: 0.10% or less, Al: 0.001 to 0.100%, N: 0.10% or less, P: 0.0020 to 0.100% Containing steel, the balance being Fe and inevitable impurities, hot rolled at a finishing temperature: (Ar3 transformation point temperature -30) ° C or higher, coiling temperature: 400-750 ° C, pickling and cold rolling After performing, it is cooled to a temperature range of 300 to 500 ° C. at a cooling rate of 10 ° C./s or more and 40 ° C./s or less, and is subjected to continuous annealing including an overaging treatment for holding at a temperature range of 300 to 500 ° C. for 5 seconds or more Then, the second cold rolling is performed at a reduction ratio of 20 to 50%. A method for producing a steel plate for a high-strength container. In mass%, C: 0.01 to 0.05%, Si: 0.04% or less, Mn: 0.1 to 1.2%, S: 0.10% or less, Al: 0.001 to 0.100%, N: 0.10% or less, P: 0.0020 to 0.020% Containing steel, the balance being Fe and inevitable impurities, hot rolled at a finishing temperature: (Ar3 transformation point temperature -30) ° C or higher, coiling temperature: 400-750 ° C, pickling and cold rolling After performing, it is cooled to a temperature range of 300 to 500 ° C. at a cooling rate of 10 ° C./s or more and 40 ° C./s or less, and is subjected to continuous annealing including an overaging treatment for holding at a temperature range of 300 to 500 ° C. for 5 seconds or more Then, the second cold rolling is performed at a reduction ratio of 20 to 50%. A method for producing a steel plate for a high-strength container.