WO2010113333A1 - Steel sheet for high‑strength container and manufacturing method thereof - Google Patents

Abstract

Provided are a steel sheet for containers that has a hardness of 500 MPa or greater and excellent workability and a manufacturing method thereof. Steel, which contains C: 0.001-0.10%, Si: 0.04% or less, Mn: 0.1‑1.2%, S: 0.10% or less, Al: 0.001‑0.100%, N: 0.10% or less, and P: 0.007‑0.100%, in % by mass, and the remainder of which is unavoidable impurities, is hot‑rolled at a finishing temperature (hot‑rolling ending temperature): (Ar3 transformation temperature – 30)°C or higher and a coiling temperature: 400-750°C, is pickled and cold‑rolled, and is then annealed continuously. Next, the steel is cold‑rolled for the second time with a rolling reduction: 10% or greater but less than 20%, and a steel sheet for high‑strength containers is obtained which has a tensile strength of 500 MPa or greater and exhibits a proof stress variation of 40 MPa or less in the sheet width direction and the rolling direction.

Description

Steel plate for high-strength container and method for producing the same

The present invention relates to a steel plate for a high-strength container suitable as a container material for reducing or expanding a diameter shape 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 higher, and then, after pickling and cold rolling, continuous annealing is performed. A method of performing secondary cold rolling has been proposed.
However, in the method of Patent Document 1, P is set to 0.02 wt% or less so that the flange workability, neck workability, and corrosion resistance are not deteriorated, and the reduction ratio of the secondary cold rolling is set to 15 to 30%. There are problems that it is difficult to efficiently process a thin product and it is difficult to produce it, and that 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, the rolling reduction in the second cold rolling is as high as 20 to 50%, and the operation efficiency is lowered due to the high rolling load. Moreover, since various rolling oils with high viscosity are used for the purpose of improving lubricity during rolling, 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 “Technical history of surface-treated steel sheets for cans in Japan” published by the Japan Steel Association on October 30, 1998 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 the plate width direction and the rolling direction of 40 MPa or less, and a container having excellent 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.
When P is secured as a component composition at a certain level and the second cold rolling is performed at a rolling reduction (10% or more and less than 20%) that is lower than the conventional rolling rolling reduction, the appearance mismatch is small, and the width direction and the rolling direction It was found that a high strength material can be secured with a small proof stress difference.
As described above, in the present invention, a steel sheet for a high-strength container has been completed by managing 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: 0.001 to 0.10%, Si: 0.04% or less, Mn: 0.1 to 1.2%, S: 0.10% or less, Al: 0.001 ~ 0.100%, N: 0.10% or less, P: 0.007 ~ 0.100%, the balance is made of Fe and inevitable impurities, the tensile strength TS is 500 MPa or more, and the sheet width direction A steel plate for a high-strength container having a difference in yield strength in the rolling direction of 40 MPa or less.
[2] By mass%, C: 0.001 to 0.10%, Si: 0.04% or less, Mn: 0.1 to 1.2%, S: 0.10% or less, Al: 0.001 ~ 0.100%, N: 0.10% or less, P: 0.007 ~ 0.100% steel, the balance consisting of Fe and inevitable impurities, finishing temperature: (Ar3 transformation temperature -30 ) C. or higher, coiling temperature: 400-750 ° C. Hot rolling, pickling and cold rolling, followed by continuous annealing, then rolling reduction: 10% or more and less than 20%, second cooling A method for producing a steel plate for a high-strength container, characterized by performing hot rolling.
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 of 500 MPa or more.
Moreover, 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 plate thickness 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.

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 TS500 MPa or more and a difference in yield strength between the plate width direction and the rolling direction of 40 MPa or less. And in this invention, in order to improve and ensure the intensity | strength before the 2nd cold rolling by addition of P, the reduction rate in the 2nd cold rolling (henceforth a secondary cold rolling may be called). Therefore, it is possible to provide a method with excellent productivity.
The component composition of the steel plate for containers according to the present invention will be described.
C: 0.001 to 0.10%
When there is much C component, the steel plate after secondary cold rolling will be hardened more than necessary, and can-making property and neck workability will deteriorate. Moreover, it becomes an element which produces a HAZ crack at the time of a flange process by remarkable hardening of a welding part. If C exceeds 0.10%, these effects become significant, so C is made 0.10% or less. On the other hand, if the C component is extremely low, secondary cold rolling at a high pressure reduction is required to maintain the strength of the container, so C is made 0.001% or more. It is preferably 0.020 to 0.050%.
Si: 0.04% or less When a large amount of Si is added, surface properties and corrosion resistance are deteriorated. Therefore, Si is made 0.04% or less.
Mn: 0.1 to 1.2%
Mn is an element effective for preventing hot cracking due to S. And the effect which prevents a crack is acquired by adding according to S amount. 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, when 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: 0.007 to 0.100%
P is a component necessary for hardening steel and obtaining a required strength, and is the most important requirement in the present invention. In order to acquire this effect, 0.007% or more of P is contained. On the other hand, including an excessive amount of P component more than necessary degrades 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%. It is preferably 0.010 to 0.020%.
S: 0.10% or less S is an element which exists as an inclusion in steel and reduces 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 becomes insufficient, and deterioration of flange workability and neck workability due to inclusions is caused. 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 is set to 0.100% or less. It is preferably 0.020 to 0.080%.
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 0.10% or less. It is preferable to make it 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 container steel plate 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 40 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 sheet width direction and the rolling direction is 40 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.
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 extraction temperature of the slab is set to 1050 ° C. or higher, a sufficiently high hot rolling end temperature can be secured in the hot rolling of the next process. On the other hand, if the heating temperature is 1300 ° C. or lower, the surface properties of the steel sheet will not be deteriorated finally. Therefore, the slab heating 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 The hot rolling end temperature is (Ar3 transformation point−) in order to improve the cold rolling property and product characteristics of the subsequent process. 30) It is necessary to set the temperature to be equal to or higher than ° C. When the temperature is lower than (Ar3 transformation point −30) ° C., the metal structure of the final product is coarsened, and rough skin is likely to occur during canning. 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. Therefore, the hot rolling end temperature is set to (Ar3 transformation point−30) ° C. or higher.
Winding temperature: 400 ~ 750 ℃
If the coiling temperature is too low, the shape of the hot-rolled sheet deteriorates, and the pickling and cold rolling operations in the next process are hindered. On the other hand, if it becomes too high, aluminum nitride precipitates at the stage of the hot-rolled mother 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 plate, which adversely affects the corrosion resistance of the steel plate. 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 set the temperature to 750 ° C. or lower.
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 which made ultra low carbon steel the 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: Recrystallization temperature of 800 ° C or less (preferred condition)
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 soaking time of 10 s or more is sufficient from the stability of the operation.
Secondary cold rolling reduction: 10% or more and less than 20% (preferably 10% or more and less than 15%)
Secondary cold rolling after continuous annealing is necessary to secure the pressure resistance of the weld can, that is, the yield strength of the steel sheet. In particular, considering the case of using ultra-low carbon steel, which is relatively soft as compared with the conventional material, as a raw material, the rolling reduction of secondary cold rolling needs to be at least 10%. On the other hand, when the rolling reduction is 20% or more, the material property anisotropy increases, and the difference in yield strength between the sheet width direction and the rolling direction exceeds 40 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, less than 20%. Furthermore, in order to ensure elongation and suppress flange cracking resistance and appearance defects, it is preferably 10% or more and less than 15%.
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.

（ｉ）引張試験
これら冷延鋼板の幅方向の中央部から圧延（Ｌ）方向に、ＪＩＳ　１３号−Ｂ引張試験片を採取し、歪速度クロスヘッド速度：１０ｍｍ／ｓで引張試験を実施し、引張強度ＴＳおよび降伏強度ＹＳを測定した。なお、引張試験は製品化後１日以内に実施した。引張試験片をＪＩＳ　１３号−Ｂ試験片としたのは、標点外で破断する現象を極力低減するためである。
これら冷延鋼板について、ＪＩＳ　Ｚ　２２４５の規定に準拠してＨＲ３０Ｔ硬さを測定した。
　（ｉｉ）幅方向と圧延方向での耐力差
上記（ｉ）の引張試験により測定したＹＳと、板幅（Ｃ）方向に採取したＪＩＳ　１３号−Ｂ引張試験片を（ｉ）と同様に測定したＹＳとの差を求めた。
　（ｉｉｉ）ネッキング加工性
これら冷延鋼板にＳｎめっき処理（片面あたりのＳｎ付着量２．８ｇ／ｍ^２）を行い、めっき鋼板とした。このめっき鋼板の表面に、塗装・印刷・透明ニス仕上げを行った後、プレス油を使用せずに前記鋼板を以下の条件でカップ絞り、さらに２度の再絞り加工を施す深絞り成形を１００回行い、ネックの絞りしわの発生率を調査した。
深絞り成形条件
ブランク径：２００ｍｍφ
潤滑条件：プレス油使用せず
第１絞りの絞り比：１．５
第２絞りの絞り比：１．２
第３絞りの絞り比：１．２
第１~３絞りのしわ押さえ圧：最適条件
フランジ加工：伸び率８％
再絞りダイス肩半径：０．４５ｍｍ
加工速度：０．３ｍ／ｓ
　（ｉｖ）耐フランジ割れ性
（ｉｉｉ）の深絞り成形において、フランジ割れの発生率を調査した。
　（ｖ）外観
これら冷延鋼板を目視で観察し、光沢や色調が異なると判断される部分を外観不良とした。観察した１００ｍ単位の中に１箇所でも外観不良が確認されればこの１００ｍを外観不良部とし、１００００ｍを観察して外観不良率を求めた。
　（ｖｉ）スラブ割れ
連続鋳造後のスラブ表面を目視でスラブ割れの状況を観察した。
観察した１ｍ単位の中に割れが１箇所でも確認されればこの１ｍを外観不良部とし、１０ｍを観察して外観不良率を求めた。
得られた結果を表２および表３に示す。

　表２および表３より、本発明例であるＮｏ．８~１０、Ｎｏ．１５~１７、Ｎｏ．２２~２４は十分な強度を有し、かつ板幅方向と圧延方向の耐力差が４０ＭＰａ以下であり、例えば、３ピース加工に必要な性能を十分に達成している。また、外観に優れ、ネックしわやフランジ割れも生じていないことが認められる。
一方、比較例のＮｏ．１、２はＰの含有量が０．００７％未満であり、かつ二次冷間圧延の圧下率も低いため、Ｎｏ．６、７、１３、１４、２０、２１は、二次冷間圧延の圧下率が低いため強度が不足している。また、Ｎｏ．４、５、１１、１２、１８、１９、２５、２６は二次冷間圧延の圧下率が２０％以上であるため強度は得られるが、板幅方向と圧延方向の耐力差が４０ＭＰａを超え、ネックしわやフランジ割れの発生が顕著である。また、外観の不良も発生している。さらに、Ｎｏ．３はＰの含有量が０．００７％未満であるため、二次冷間圧延の圧下率を１０％としても強度が不足する。
さらに、表３のＮｏ．１５~１７、Ｎｏ．２２~２４は、Ｎ含有量を０．００７０％、０．００２５％と好適範囲：０．０１％未満とした実施例である。表３より、Ｎ含有量を０．０１％未満とすることで、スラブ割れが全く確認されず、スラブ割れが防止されているのがわかる。
また、二次冷間圧延の圧下率を好適範囲である１０％以上１５％未満とすることで、フランジ割れおよび外観不良が完全に抑えられ、さらに良好な結果となっているのがわかる。また、強度は小さくなる傾向にあるが、５００ＭＰａ以上の十分な強度が得られる。
　本発明によれば５００ＭＰａ以上のＴＳを有し、板幅方向と圧延方向の耐力差が４０ＭＰａ以下であり、かつ、フランジ加工やネッキング加工時に割れが生じない加工性に優れた高強度容器用鋼板が得られる。
さらに、本発明では、Ｐ成分を用いて硬質化することで２回目の冷間圧延での圧下率を低くできるため、操業効率が高くなり生産性に優れる上、圧延後の外観の問題や幅方向と圧延方向での耐力差の問題が解消される。
また、Ｎ成分を好適範囲である０．０１％未満とすることで、スラブ割れを防止し、製品での歩留まり低下を抑えることができる。 A steel containing the components shown in Table 1 and the balance being Fe and inevitable 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 winding temperature of 650 ° C. to obtain hot rolled sheets having a finished thickness of 2.0 mm. Thereafter, the hot-rolled sheets are descaled by pickling, and further cold-rolled with a reduction rate of 90% to obtain cold-rolled sheets having a finished thickness of 0.20 mm. Continuous annealing at ˜30 s and secondary cold rolling at the rolling reduction shown in Tables 2 and 3 were performed to obtain cold-rolled steel sheets.
The steel plate obtained as described above was subjected to the following tests to evaluate the characteristics.

(I) Tensile test JIS No. 13-B tensile test specimens were collected from the center in the width direction of these cold-rolled steel sheets in the rolling (L) direction 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 No. 13-B test piece is to reduce as much as possible the phenomenon of breaking outside the gauge.
About these cold-rolled steel plates, HR30T hardness was measured based on the prescription | regulation of JISZ2245.
(Ii) Yield difference between width direction and rolling direction YS measured by tensile test of (i) above and JIS No. 13-B tensile specimen taken in the plate width (C) direction were measured in the same manner as (i). The difference from YS was determined.
(Iii) Necking workability These cold-rolled steel sheets were Sn-plated (Sn adhesion amount per side 2.8 g / m ² ) 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 the third aperture: 1.2
Wrinkle holding pressure of 1st to 3rd aperture: Optimal condition Flange processing: Elongation rate 8%
Redrawing die shoulder radius: 0.45mm
Processing speed: 0.3 m / 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. If 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 10,000 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 obtained results are shown in Tables 2 and 3.

From Table 2 and Table 3, No. which is an example of the present invention. 8-10, no. 15-17, no. Nos. 22 to 24 have sufficient strength, and the difference in yield strength between the sheet width direction and the rolling direction is 40 MPa or less, and for example, the performance necessary for three-piece processing is sufficiently achieved. Moreover, it is recognized that the appearance is excellent and neck wrinkles and flange cracks are not generated.
On the other hand, no. Nos. 1 and 2 have a P content of less than 0.007% and a low reduction ratio of secondary cold rolling. 6, 7, 13, 14, 20, and 21 are insufficient in strength because the rolling reduction of secondary cold rolling is low. No. 4, 5, 11, 12, 18, 19, 25, and 26 provide strength because the rolling reduction of secondary cold rolling is 20% or more, but the difference in yield strength between the sheet width direction and the rolling direction exceeds 40 MPa. Neck wrinkles and flange cracks are prominent. Moreover, the appearance defect has also occurred. Furthermore, no. No. 3 has a P content of less than 0.007%, so that the strength is insufficient even when the rolling reduction of the secondary cold rolling is 10%.
Further, in Table 3, No. 15-17, no. Examples 22 to 24 are examples in which the N content is 0.0070% and 0.0025%, and the preferred 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.
Moreover, it turns out that a flange crack and an external appearance defect are completely suppressed by making the rolling reduction rate of secondary cold rolling 10% or more and less than 15% which is a suitable range, and it has become a more favorable result. Further, although the strength tends to be small, a sufficient strength of 500 MPa or more can be obtained.
According to the present invention, a steel plate for a high-strength container having a TS of 500 MPa or more, a difference in yield strength between the sheet width direction and the rolling direction of 40 MPa or less, and excellent workability that does not cause cracking during flange processing or necking processing Is obtained.
Furthermore, in the present invention, since the reduction ratio in the second cold rolling can be lowered by hardening using the P component, the operational efficiency is increased and the productivity is excellent, and the appearance problems and width after rolling are reduced. The problem of the difference in yield strength between the direction and the rolling direction is solved.
Moreover, by making N component into less than 0.01% which is a suitable range, a slab crack can be prevented and the yield fall in a product can be suppressed.

The steel plate for containers of the present invention can provide excellent strength without cracking in necking and flange processing. 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: 0.001 to 0.10%, 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: 0.007 to 0.100%, the balance is made of Fe and inevitable impurities, the tensile strength TS is 500 MPa or more, and in the sheet width direction and the rolling direction A steel plate for high-strength containers having a proof stress difference of 40 MPa or less. By mass%, C: 0.001 to 0.10%, Si: 0.04% or less, Mn: 0.1 to 1.2%, S: 0.10% or less, Al: 0.001 to 0. 100%, N: less than 0.010%, P: 0.007 to 0.100%, the balance is made of Fe and inevitable impurities, the tensile strength TS is 500 MPa or more, and in the sheet width direction and the rolling direction A steel plate for high-strength containers having a proof stress difference of 40 MPa or less. In mass%, C: 0.001 to 0.10%, Si: 0.04% or less, Mn: 0.1 to 1.2%, S: 0.10% or less, Al: 0.001 to 0. Steel containing 100%, N: 0.10% or less, P: 0.007 to 0.100%, the balance being Fe and inevitable impurities, finishing temperature: (Ar3 transformation temperature -30) ° C or more , Coiling temperature: hot rolling at 400-750 ° C., pickling, cold rolling, continuous annealing, then rolling reduction: 10% or more and less than 20%, the second cold rolling The manufacturing method of the steel plate for high strength containers characterized by performing. By mass%, C: 0.001 to 0.10%, Si: 0.04% or less, Mn: 0.1 to 1.2%, S: 0.10% or less, Al: 0.001 to 0. Steel containing 100%, N: less than 0.010%, P: 0.007 to 0.100%, the balance being Fe and inevitable impurities, finishing temperature: (Ar3 transformation point temperature -30) ° C or higher Winding temperature: Hot rolling at 400 to 750 ° C., pickling and cold rolling, followed by continuous annealing, then rolling reduction: 10% or more and less than 20% for the second cold rolling The manufacturing method of the steel plate for high strength containers characterized by performing.