JP2001107189A - Extra-thin steel sheet excellent in homogeneity of material in coil and its producing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To proivde a stock for a thin WALL vessel producible with high productivity and also at a low cost and uniform in the material in a coil without requiring the conventional strict temperature control and special equipment investment. SOLUTION: By steel containing, by weight, 0.0040 to 0.0300% N and 0.005 to 0.080% Al, and in which the content of C is controlled to <=0.0400% at need under the conditions free from any special control of the uniformity of hot rolling temperature in a coil, i.e., under the conditions that hot rolling finishing temperature is <=930 deg.C, the temperature difference between the width central part and the width edge parts is >=20 deg.C, coiling temperature is >=200 deg.C, the temperature difference between the width central part and the width edge parts is >=30 deg.C, and the temperature difference between the longitudinal central position and the longitudinal tip or terminal position is >=30 deg.C, a steel sheet in which the variation of the material (standard deviation) between the width position and the longitudinal position is 20 MPa by 0.2% proof stress, is <=20 MPa by the maximum load, and <=2% by an earing ratio is produced. In particular, N may be contained to <=0.0300% by executing nitriding treatment in a continuous annealing furnace.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は飲料缶などの金属容
器に利用される鋼板およびその製造方法に関するもので
ある。具体的にはコイルの幅または長手位置における材
質変動の小さい鋼板およびその鋼板を、製造工程におい
て製造条件の厳密な制御なしに製造する方法に関するも
のである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel plate used for a metal container such as a beverage can and a method for producing the same. More specifically, the present invention relates to a method of manufacturing a steel sheet having a small variation in material at a coil width or a longitudinal position and a steel sheet without strict control of manufacturing conditions in a manufacturing process.

【０００２】[0002]

【従来の技術】飲料缶、食品缶などに代表される容器用
鋼板については、缶コスト低減のため、素材の薄手化が
求められている。薄手材の製缶加工においては金型形状
や金型間のクリアランスなど金型配置、さらには潤滑条
件や絞り成形でのしわ抑え荷重などが、規定の鋼板に合
わせて非常に狭い範囲で高精度に調整されているため、
僅かな材質の変動が成形不良につながりやすく、より均
質な素材が求められている。通常はこのような鋼板はコ
イルで供給されるため、具体的にはコイル幅および長手
位置での材質の変動が小さいことが求められている。2. Description of the Related Art As for steel plates for containers represented by beverage cans, food cans and the like, thinner materials are required to reduce the cost of cans. In can processing of thin materials, mold configuration such as mold shape and clearance between molds, as well as lubrication conditions and wrinkle suppression load in draw forming are highly accurate in a very narrow range according to the specified steel plate. Is adjusted to
A slight variation in the material easily leads to molding failure, and a more homogeneous material is required. Usually, such a steel sheet is supplied by a coil, and specifically, it is required that the material change at the coil width and the longitudinal position is small.

【０００３】一方、鋼板の製造においては鋼板の材質を
コイル内で均質に造り込むことは薄手化に伴い困難とな
る。この理由は主として製品板厚の薄手化に伴い熱延板
厚を薄くすると、熱延時のコイル内での温度の変動が大
きくなることに起因している。具体的には熱延中の温度
低下がコイル幅端部や長手先端、終端で中央部より大き
くなるためである。On the other hand, in the manufacture of a steel sheet, it is difficult to uniformly form the material of the steel sheet in the coil as the thickness is reduced. The main reason for this is that when the thickness of the hot-rolled sheet is reduced in accordance with the reduction in the thickness of the product, the temperature fluctuation in the coil during hot-rolling increases. Specifically, the temperature drop during hot rolling is greater at the coil width end, the longitudinal end, and the end than at the center.

【０００４】これを解決する手段として特開昭６１−２
０７５２０号公報、特開平９−１０４９２０号公報、特
開平９−１７６７４４号公報による技術が開示されてい
る。これら従来の技術に共通するのは、通常の操業では
温度の変動が大きくなる上記部位の温度を何らかの方法
により昇温または温度低下を抑制するという非常に直接
的な方法を適用していることである。しかし、これらの
方法は高精度の温度管理が必要なため生産性の低下を招
き、またそのような制御を行うために何らかの設備改造
に伴う投資が必要なため、素材コストの上昇が避けられ
ない。As means for solving this problem, Japanese Patent Laid-Open No.
Japanese Patent Application Laid-Open Nos. 07520, 9-104920 and 9-176744 disclose techniques. What is common to these conventional technologies is that a very direct method of suppressing the temperature rise or temperature decrease by some method is applied to the temperature of the above-mentioned portion where the temperature fluctuation is large in normal operation. is there. However, these methods require high-precision temperature control, which causes a decrease in productivity, and in order to perform such control, investment for some equipment remodeling is required, so that an increase in material costs is inevitable. .

【０００５】[0005]

【発明が解決しようとする課題】以上述べたように、従
来技術では素材コストが上昇するため、素材の薄手化に
より缶コストを低減するという目的には好ましい素材と
は言えない。本発明の目的は、従来のような厳格な温度
制御が不要で、かつ特殊な設備投資も必要とせず、コイ
ル内での材質が均一な素材を提供することにある。As described above, since the cost of the material increases in the prior art, it is not a preferable material for the purpose of reducing the cost of the can by making the material thinner. An object of the present invention is to provide a material having a uniform material in a coil without requiring strict temperature control as in the related art and without requiring special equipment investment.

【０００６】[0006]

【課題を解決するための手段】本発明者らは、特に焼鈍
後の２ＣＲにより強度を調整した板厚０．４mm以下の鋼
板の成分、特に固溶Ｃ，Ｎと熱延条件が材質に及ぼす影
響を検討するうち、成分、特にＮを特定範囲に限定した
鋼板では素材特性が熱延条件の影響を受けにくい場合が
あることを知見し、通常の熱延での操業条件におけるコ
イル内の温度変動との関連でさらなる検討を加え、本発
明を完成した。Means for Solving the Problems The present inventors have found that the composition of a steel sheet having a thickness of 0.4 mm or less, in particular, the strength of which is adjusted by 2CR after annealing, particularly the solute C and N, and the hot rolling conditions affect the material. In examining the effects, it was found that the material properties of steel sheets, in which the components, especially N, were limited to a specific range, were sometimes hard to be affected by the hot rolling conditions, and the temperature inside the coil under normal hot rolling operating conditions was found. Further investigations in the context of variations have led to the completion of the present invention.

【０００７】かかる状況下で成された本発明は、以下の
構成を要旨とする。すなわち、コイル内の熱延温度の均
一性に何ら特別な制御をしないような条件、すなわち熱
延仕上げ温度が９３０℃以下で幅中央部と幅端部の温度
差を２０℃以上、巻取り温度については７５０℃以下２
００℃以上の巻取で幅中央部と幅端部の温度差が３０℃
以上、長手中央位置と長手先端または終端位置での温度
差が３０℃以上という条件において、重量％でＮ：０．
００４０〜０．０３００％、Ａｌ：０．００５〜０．０
８０％を含有し、必要に応じてＣ：０．０４００％以下
とした鋼で、幅位置および長手位置での材質ばらつき
（標準偏差）がＪＩＳ５号引張り試験における０．２％
耐力で２０ＭＰａ以内、最高荷重で２０ＭＰａ以内、イ
ヤリング率で２．０％以内である鋼板を製造することで
ある。特にＮについては、冷延後、連続焼鈍炉内で再結
晶焼鈍をした後、窒化処理により０．０３００％以下ま
で含有させることでも製造が可能である。The gist of the present invention made under such circumstances is as follows. That is, a condition in which there is no special control on the uniformity of the hot rolling temperature in the coil, that is, the hot rolling finish temperature is 930 ° C. or less, the temperature difference between the width center portion and the width end portion is 20 ° C. or more, and the winding temperature About 750 ° C or less 2
Temperature difference between center of width and end of width is 30 ° C by winding at 00 ° C or more
As described above, under the condition that the temperature difference between the longitudinal center position and the longitudinal end or end position is 30 ° C. or more, N: 0.
0040 to 0.0300%, Al: 0.005 to 0.0
80%, and if necessary, C: 0.0400% or less, the material variation (standard deviation) at the width position and the longitudinal position is 0.2% in the JIS No. 5 tensile test.
The purpose is to manufacture a steel sheet having a proof stress of 20 MPa or less, a maximum load of 20 MPa or less, and an earring rate of 2.0% or less. In particular, N can also be produced by cold rolling, performing recrystallization annealing in a continuous annealing furnace, and then adding up to 0.0300% or less by nitriding.

【０００８】[0008]

【発明の実施の形態】以下、本発明を詳細に説明する。
まず、本発明における語の意味について説明する。本発
明中の記述において、長手中央部、長手先端部、長手終
端部、幅中央部、幅端部などの表現を用いているが、本
発明においては長手先端部はコイル長さの先端１５ｍ、
長手終端部はコイル長さの終端１５ｍ、長手中央部は先
端と終端を除いた部分、幅端部はコイルの両幅エッジか
ら全幅の１／８の幅内の部分、幅中央部は幅端部を除い
た部分と定義する。このため例えば長手中央部でも長手
位置により温度は少なからず異なる。このため本発明の
限定を評価する場合には、各部の温度を代表するように
偏りの無い部内の数点で温度を測定し、平均値をもつて
判定することが望ましい。BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
First, the meaning of the word in the present invention will be described. In the description of the present invention, expressions such as a longitudinal central portion, a longitudinal tip portion, a longitudinal end portion, a width central portion, and a width end portion are used, but in the present invention, the longitudinal tip portion is a coil length tip 15 m,
The longitudinal end is the end of the coil length 15m, the longitudinal center is the part excluding the tip and the end, the width end is the part within 1/8 of the total width from both width edges of the coil, and the width center is the width end Is defined as the part excluding the part. For this reason, for example, even at the central portion in the longitudinal direction, the temperature varies depending on the longitudinal position. For this reason, when evaluating the limitation of the present invention, it is desirable to measure the temperature at several points in an unbiased part so as to represent the temperature of each part, and to determine the average value.

【０００９】次に、成分について説明する。成分はすべ
て重量％である。Ｎは本発明の重要規定要件である。
０．００４０％未満では本発明の効果は得られない。望
ましくは０．００６０％以上である。また上限は鋳造欠
陥の可能性や窒化鉄形成による加工性劣化から０．０３
００％とする。Next, the components will be described. All components are% by weight. N is an important requirement of the present invention.
If less than 0.0040%, the effects of the present invention cannot be obtained. Desirably, it is 0.0060% or more. The upper limit is set to 0.03 due to the possibility of casting defects and deterioration in workability due to the formation of iron nitride.
00%.

【００１０】Ａｌは脱酸を目的として添加され０．００
５％以上含有される。Ｎ含有量が高い本発明鋼ではＡｌ
の含有量が高くなると鋼中に微細に析出するＡｌＮの析
出量が増大し再結晶を抑制する場合があるため、焼鈍時
に高温通板が必要となり通板性を顕著に劣化させる。そ
のため０．０８０％を上限とする。好ましい範囲は０．
０１０〜０．０６０％である。[0010] Al is added for the purpose of deoxidation, and 0.00
It is contained in 5% or more. In the steel of the present invention having a high N content, Al
When the content of Al increases, the precipitation amount of AlN that precipitates finely in the steel increases and recrystallization may be suppressed, so that high-temperature threading is required at the time of annealing, which significantly deteriorates sheetability. Therefore, the upper limit is 0.080%. The preferred range is 0.
010 to 0.060%.

【００１１】Ｃは０．０４００％超では本発明の効果が
小さくなる。望ましくは０．０１５０％以下、発明の効
果を最大に活用するには０．００５０％以下とすること
が望ましい。When C exceeds 0.0400%, the effect of the present invention is reduced. It is desirably 0.0150% or less, and 0.0050% or less for maximizing the effects of the invention.

【００１２】通常の鋼板に不可避的にあるいは特定の目
的のために含有されるＭｎ，Ｓｉ，Ｐ，Ｓ等は、一般に
容器用に用いられる鋼板に含有される程度に含有され
る。その範囲はＭｎ：０．０２〜２．０％、Ｓｉ：０．
００１〜０．１０％、Ｐ：０．００２〜０．０４０％、
Ｓ：０．００２〜０．０４０％であるが、特に限定する
ものではない。その他、製鋼工程でのスクラップ使用な
どで混入する各種の不純物元素も、通常の鋼板に含有さ
れる程度に含有することは本発明の効果を損なうもので
はない。Mn, Si, P, S and the like which are unavoidably contained in a normal steel plate or for a specific purpose are contained to the extent that they are generally contained in a steel plate used for containers. The range is as follows: Mn: 0.02 to 2.0%, Si: 0.
001 to 0.10%, P: 0.002 to 0.040%,
S: 0.002 to 0.040%, but not particularly limited. In addition, the effects of the present invention are not impaired if various impurity elements that are mixed in with the use of scrap in the steelmaking process are contained to the extent that they are contained in ordinary steel sheets.

【００１３】材質としてはコイル内での材質ばらつきが
コイル内で複数点測定した材質の標準偏差について、Ｊ
ＩＳ５号引張試験での０．２％耐力で２０ＭＰａ、最高
荷重で２０ＭＰａ以内であり、イヤリング率が２％以内
となつているものを本発明の対象とする。これは材質変
動がこれ以上に大きいものでは製缶時の成形不良が発生
する可能性が大きくなるためである。As for the material, the variation in the material within the coil is determined by the standard deviation of the material measured at a plurality of points in the coil.
The subject matter of the present invention is the one in which the 0.2% proof stress in the IS5 tensile test is 20 MPa, the maximum load is 20 MPa or less, and the earring ratio is 2% or less. This is because if the material variation is larger than this, the possibility of occurrence of molding failure during can manufacturing increases.

【００１４】標準偏差はサンプルの選び方により変動す
る。このためコイル内での測定点数は前述のコイル内の
各部に対し同じ程度の重み付けがなされ、偏りがない程
度に多数の点について測定される必要がある。本発明で
の標準的な測定位置は、長手位置としてコイル先端と終
端からそれぞれ５，１０ｍで各２点、ならびにコイル長
手中央部のコイル長さにわたつて１／５毎の４点で、合
計８点、幅位置では両最エッジ、幅の１／４，１／２，
３／４の５点で合計４０点とする。これにより長手位置
については中央部で２０点、先端および終端の端部で２
０点の測定となり、長手位置での材質均一化で問題とな
る先端、終端での材質変動を適当に評価できる。また、
幅位置については幅中央部で２４点、幅端部で１６点で
ある。特に幅位置での材質の変動が懸念される場合に
は、さらに幅端から５０または１００mm位置での測定値
も追加し、幅端部の合計で３２点としてもよい。The standard deviation varies depending on how the sample is selected. For this reason, the number of measurement points in the coil needs to be weighted to the same degree for each part in the coil, and measured for as many points as possible without bias. The standard measurement positions in the present invention are two points each at 5 and 10 m from the coil tip and end, respectively, as the longitudinal position, and four points every 1/5 over the coil length at the center of the coil longitudinal section. 8 points, both edges at width position, 1/4, 1/2, width
A total of 40 points out of 5 points of 3/4. As a result, the longitudinal position is 20 points at the center and 2 points at the leading and trailing ends.
The measurement is performed at the zero point, and the material variation at the leading end and the trailing end, which is a problem in uniformizing the material at the longitudinal position, can be appropriately evaluated. Also,
The width position is 24 points at the width center and 16 points at the width end. In particular, when there is a concern about a change in the material at the width position, a measurement value at a position 50 or 100 mm from the width end may be further added, and a total of 32 points at the width end may be set.

【００１５】測定位置は、目的とする材質測定用に採取
した試験片の中央部の位置をコイル内での相当位置とす
るが、例えば幅最端部については試験片中央をコイルの
最端部とすることは不可能である。この場合には試験片
中央部ができるだけ幅最端部に近づくように、言いかえ
れば試験片の一部がコイル幅最端部となるように試験片
を採取することとする。The measurement position is the position of the center of the test piece sampled for measuring the target material, which is the equivalent position in the coil. For example, for the end of the width, the center of the test piece is set at the end of the coil. Is impossible. In this case, the test piece is collected so that the center of the test piece is as close as possible to the end of the width, in other words, a part of the test piece is at the end of the coil width.

【００１６】熱延工程を経ることは必要な条件ではない
が、通常、コイル内の材質ばらつきの主要因の一つが熱
延工程にあることを考え、熱延条件のいくつかを以下の
理由で限定する。熱延板厚は３．０mm以下とする。これ
は熱延板厚が厚い場合には鋼板の熱容量が大きいため、
材質変動の原因となる熱延工程でのコイル内の温度変動
が比較的小さくなり、コイル内の材質変動が問題となり
難いためである。Although it is not a necessary condition to go through the hot rolling step, usually, considering that one of the main factors of the material variation in the coil is the hot rolling step, some of the hot rolling conditions are changed for the following reasons. limit. The thickness of the hot rolled sheet is 3.0 mm or less. This is because when the hot rolled sheet is thick, the heat capacity of the steel sheet is large,
This is because temperature fluctuation in the coil during the hot rolling process, which causes the material fluctuation, becomes relatively small, and the material fluctuation in the coil hardly causes a problem.

【００１７】熱延仕上げ温度は板幅の中央部で９３０℃
以下とする。これは板幅中央部での熱延仕上げ温度がこ
れ以上に高い場合には、幅端部や長手先端・終端でも比
較的高い温度を確保できるようになり、温度が材質に及
ぼす影響が小さくなるためである。この温度は、熱延中
の仕上げ圧延機出側でコイル全長にわたつて測定される
温度の平均値と定義する。The hot rolling finish temperature is 930 ° C. at the center of the sheet width.
The following is assumed. This means that if the hot-rolling finishing temperature at the center of the sheet width is higher than this, a relatively high temperature can be secured even at the width end, the longitudinal end, and the end, and the effect of the temperature on the material is reduced. That's why. This temperature is defined as the average of the temperatures measured over the entire length of the coil at the exit of the finishing mill during hot rolling.

【００１８】熱延巻取り温度は７５０℃以下２００℃以
上とする。これはこの温度以上では上記と同様に端部で
の温度確保が容易となり、材質への影響が小さくなるた
めである。また、これ以下の温度では温度が材質に及ぼ
す影響が小さくなるためである。The hot-rolling temperature is 750 ° C. or lower and 200 ° C. or higher. This is because, when the temperature is higher than this, it is easy to secure the temperature at the end portion similarly to the above, and the influence on the material is reduced. Further, at a temperature lower than this, the influence of the temperature on the material is reduced.

【００１９】熱延仕上げ温度については幅中央部と幅端
部の差を２０℃以上とする。これは例えば特開平９−１
０４９２０公報のような技術により、温度差を小さくす
れば材質変動も小さくなることは既に知られており、本
発明はこれら以外を対象とするからである。Regarding the hot-rolling finishing temperature, the difference between the width center portion and the width end portion is set to 20 ° C. or more. This is described in, for example,
It is already known that a technique such as that disclosed in Japanese Patent No. 04920 discloses that a change in material can be reduced by reducing the temperature difference, and the present invention covers other than these.

【００２０】熱延巻取り中の同一長手位置での幅中央部
と幅端部の温度差は３０℃以上とする。この理由は上記
と同様、温度差が小さければ材質変動も小さくなること
知られており、本発明はこれら以外を対象とするからで
ある。なお、コイル長手位置についてはコイル先端、終
端などの特殊な位置を除いた長手中央部で測定するもの
とする。The temperature difference between the width center and the width end at the same longitudinal position during hot rolling is 30 ° C. or more. The reason for this is that, similarly to the above, it is known that if the temperature difference is small, the material variation is also small, and the present invention covers other than these. Note that the coil longitudinal position is measured at the longitudinal central portion excluding special positions such as the coil tip and terminal.

【００２１】熱延巻取り中の幅中央部での長手中央部と
長手先端または終端部の温度差を３０℃以上とする。こ
の理由も温度差を小さくすれば材質変動も小さくなるこ
とは知られており、本発明はこれら以外を対象とするか
らである。The temperature difference between the central longitudinal portion and the longitudinal end or end portion at the central width portion during hot rolling is 30 ° C. or more. It is also known that, when the temperature difference is reduced, the material variation is also reduced, and the present invention covers other than these.

【００２２】板厚は本発明鋼の用途を考え、０．４００
mm以下と限定する。本発明鋼が特に必要とされるのは、
材質変動がより顕著となる０．２００mm以下、さらに効
果が発揮されるのは０．１７０mm以下の極薄鋼板におい
てである。Considering the use of the steel of the present invention, the thickness is set to 0.400.
mm or less. The steel of the present invention is particularly required,
An ultra-thin steel sheet having a thickness of 0.200 mm or less, at which the material variation becomes more remarkable, and a further effect is exhibited, is obtained with an extremely thin steel sheet of 0.170 mm or less.

【００２３】鋼板の０．２％耐力、全伸びは、成分、２
ＣＲ条件により変化し、従来鋼と同様に材質調整される
が、２ＣＲ率が高くなると材質が圧延による加工硬化に
支配されるようになるため、従来技術によるものでもコ
イル内の材質は均質化の方向に向かう。本発明の効果が
必要になるのは、特に２ＣＲ率が１５％以下で製造され
る鋼板である。特に２ＣＲ率が５％以下の鋼では、本発
明鋼と従来鋼の違いがより顕著になる。The 0.2% proof stress and the total elongation of the steel sheet
The material is adjusted according to the CR conditions, and the material is adjusted in the same manner as conventional steel. However, as the 2CR ratio increases, the material becomes dominated by work hardening by rolling. Head in the direction. The effect of the present invention is particularly required for a steel plate manufactured at a 2CR ratio of 15% or less. Particularly, in a steel having a 2CR ratio of 5% or less, the difference between the steel of the present invention and the conventional steel becomes more remarkable.

【００２４】また本発明鋼では焼鈍条件による材質の変
動も非常に小さいため、焼鈍条件の限定が不要で、焼鈍
後の組織が再結晶していれば本発明の効果を得ることが
できる。通常、材質制御には焼鈍条件、特に最高到達温
度と高温での保定時間の管理が重要で、材質を造り分け
るため焼鈍温度を変化させる場合には、変化させている
間および変化させた後の炉温が安定するまで通板が停滞
または無駄な板を通板する必要がある。このためユーザ
ーの要求に応じ様々な板厚および材質の鋼板を製造する
に当たり、焼鈍炉の温度の変動を極力小さくし通板速度
を一定として製造できるような通板スケジュールを組む
必要が生じるが、このための労力は甚大なものがあり、
また生産性を阻害させない完全なスケジュールを組むこ
とは不可能である。本発明鋼では材質に及ぼす焼鈍条件
の影響が非常に小さいため、実質的にスケジュールフリ
ー化が達成できるというメリットも享受できる。Further, in the steel of the present invention, since the change in the material due to the annealing conditions is very small, it is not necessary to limit the annealing conditions, and the effects of the present invention can be obtained if the structure after annealing is recrystallized. Usually, in the material control, it is important to control the annealing conditions, especially the retention time at the highest temperature and high temperature, and when changing the annealing temperature to separate the materials, during and after the change It is necessary to pass through the stagnation plate or useless plates until the furnace temperature becomes stable. Therefore, when manufacturing steel plates of various thicknesses and materials according to the user's requirements, it is necessary to set a passing schedule so that the fluctuation in the temperature of the annealing furnace can be minimized and the passing speed can be kept constant, The effort for this is enormous,
Moreover, it is impossible to make a complete schedule that does not hinder productivity. In the steel of the present invention, since the influence of the annealing conditions on the material is very small, the merit that schedule-free can be substantially achieved can be enjoyed.

【００２５】本発明で重要な因子であるＮは、冷延後の
連続焼鈍時の再結晶の後に窒化処理で含有させても本発
明の効果を得ることができる。この時は窒化によるＮの
含有量の増加重を２０〜３００ppm とし、さらに窒化後
の含有Ｎ量が０．０３００％以下と限定する。この理由
は、後述のように固溶Ｎによると考えられる本発明の効
果を得るには、ほとんどが固溶Ｎとして残存する窒化に
よるＮの増加が２０ppm 以上であることが必要なこと
と、窒化後の含有Ｎ量がこれ以上になると加工性が劣化
することによる。The effect of the present invention can be obtained even if N, which is an important factor in the present invention, is incorporated by nitriding after recrystallization during continuous annealing after cold rolling. At this time, the increasing weight of the N content due to nitriding is set to 20 to 300 ppm, and the N content after nitriding is limited to 0.0300% or less. The reason for this is that in order to obtain the effect of the present invention, which is considered to be due to solid solution N, as described later, it is necessary that the increase of N due to nitridation that remains mostly as solid solution N is 20 ppm or more. This is because when the content of N later becomes more than this, the workability deteriorates.

【００２６】また、熱間圧延終了後の板幅と鋼板として
の最終製品での板幅の差を２００mm以下とする。好まし
くは６０mm以下とする。これは前述のような材質ばらつ
きの主たる原因である熱延時の温度変動部、すなわち幅
端部を両端部で熱延終了後に切り捨てればコイル内の材
質変動を小さくできることは知られており、本発明はこ
れら以外を対象とするからである。The difference between the sheet width after the completion of hot rolling and the sheet width of the final product as a steel sheet is 200 mm or less. Preferably, it is 60 mm or less. It is known that the main cause of the above-mentioned material variation is the temperature fluctuation part during hot rolling, that is, if the width end is cut off at both ends after the end of hot rolling, material fluctuation in the coil can be reduced. This is because the invention covers other than these.

【００２７】本発明では、特にＮを本発明範囲内に限定
することで、特定の熱延温度条件で製造される鋼板にお
いてコイル内の材質均一化の効果を得ることができる。
このメカニズムは明らかではないが、固溶Ｃ，Ｎまたは
非常に微細な炭化物や窒化物が大きな役割を果たしてい
ると考えられる。通常、コイル端部での材質変動は熱延
での温度の変動が、主としてＡｌＮやセメンタイトなど
の析出物の形態に影響を及ぼすことや、熱間での圧延中
の温度の変動が鋼の変態点をまたぐ場合には結晶組織に
影響することに起因している。これに対し本発明鋼で
は、固溶または微細析出物を形成するＣ，Ｎが、温度変
動に起因する材質変動を支配する要因となり、また、こ
の影響は温度の影響に鈍感であるため、上記のような通
常鋼で見られるような影響を隠蔽し材質の変動を小さく
してしまうものと思われる。また、材質評価時において
も材質が固溶または微細析出物を形成しているＣ，Ｎで
支配的に決定されてしまうため、材質の変動が見られな
くなるものと思われる。本発明の効果が特に鋼中への固
溶限の大きなＮの影響を顕著に示すことから考えると、
固溶元素の効果である可能性が高いと考えられる。In the present invention, in particular, by limiting N within the range of the present invention, the effect of equalizing the material inside the coil can be obtained in a steel sheet manufactured under a specific hot rolling temperature condition.
Although the mechanism is not clear, it is considered that solid solution C, N or very fine carbide or nitride plays a large role. In general, the material fluctuation at the coil end is caused by the temperature fluctuation in hot rolling mainly affecting the morphology of precipitates such as AlN and cementite, and the temperature fluctuation during hot rolling is caused by the transformation of steel. This is due to the influence on the crystal structure when crossing points. On the other hand, in the steel of the present invention, C and N which form a solid solution or fine precipitates become a factor that governs the material variation caused by the temperature variation, and this effect is insensitive to the temperature. It is thought that the influences such as those normally observed in steel are concealed and the fluctuation of the material is reduced. Also, at the time of material evaluation, since the material is determined dominantly by C and N which form a solid solution or a fine precipitate, it is considered that there is no change in the material. Considering that the effect of the present invention particularly shows the influence of N having a large solid solubility limit in steel,
It is considered that the possibility of the effect of the solid solution element is high.

【００２８】本発明の効果は本発明で限定された製造履
歴によらない。熱延を行う場合のスラブはインゴット
法、連続鋳造法など製造法は限定されず、また熱延に至
るまでの熱履歴にもよらないため、スラブ再加熱法、鋳
造したスラブを再加熱することなく直接熱延するＣＣ−
ＤＲ法、さらには粗圧延などを省略した薄スラブ鋳造、
さらに粗バーを接合してコイル先端または終端での不連
続を無くした連続熱延によつても本発明の効果を得るこ
とができる。The effect of the present invention does not depend on the manufacturing history limited by the present invention. The slab for hot rolling is not limited to the ingot method, continuous casting method and other manufacturing methods, and it does not depend on the heat history up to hot rolling, so the slab reheating method, reheating the cast slab CC-
DR slab, and thin slab casting without rough rolling, etc.
Further, the effect of the present invention can also be obtained by continuous hot rolling in which a rough bar is joined to eliminate discontinuity at the leading end or the trailing end of the coil.

【００２９】また、用途に応じ特定の特性、例えば二次
加工性、深絞り性、耐食性などの改善を図るためＢ，Ｎ
ｂ，Ｔｉ，Ｖ，Ｍｏ，Ｃｒ，Ｎｉなどの元素を添加して
も本発明の効果が失われるものではない。通常、本発明
鋼板は表面処理鋼板用の原板として使用されるが、表面
処理により本発明の効果はなんら損なわれるものではな
い。缶用表面処理としては通常、錫、クロム（ティンフ
リー）などが施される。また、近年使用されるようにな
つている有機皮膜を貼つたラミネート鋼板用の原板とし
ても本発明の効果を損なうことなく使用できる。In order to improve specific properties such as secondary workability, deep drawability, corrosion resistance, etc., B, N
The effects of the present invention are not lost even if elements such as b, Ti, V, Mo, Cr, and Ni are added. Usually, the steel sheet of the present invention is used as an original sheet for a surface-treated steel sheet, but the surface treatment does not impair the effects of the present invention at all. As the surface treatment for cans, tin, chromium (tin-free) or the like is usually applied. In addition, it can be used as a base plate for a laminated steel sheet to which an organic film, which has recently been used, is attached without impairing the effects of the present invention.

【００３０】[0030]

【実施例】表１に示す各成分を含有するスラブを１２０
０℃に加熱し、９００℃で仕上げた熱間圧延板を、６５
０℃で巻き取った。この熱延板を圧下率９２％の冷間圧
延を施した後、７３０℃×１分の焼鈍を行い、圧下率２
％の再冷延を行う工程を基本条件とし、板厚０．１８m
m、板幅１０００mmの表２に示す６コイルを製造した。
表２の鋼番号中１，２，５，６は基本条件で製造し、鋼
番号３は熱延後鋼板エッジ片側を１００mmトリムし、焼
鈍温度を８００℃とした。また、鋼番号４は焼鈍後窒化
処理を行い、窒化後の鋼中含有Ｎが０．０２５０％とな
るようにした。EXAMPLE A slab containing each component shown in Table 1 was used for 120
The hot-rolled plate heated to 0 ° C and finished at 900 ° C
Wound at 0 ° C. After subjecting this hot-rolled sheet to cold rolling at a rolling reduction of 92%, annealing at 730 ° C. × 1 minute was performed to reduce the rolling reduction to 2%.
% As a basic condition and a thickness of 0.18m
The six coils shown in Table 2 having an m and a board width of 1000 mm were manufactured.
Steel numbers 1, 2, 5, and 6 in Table 2 were manufactured under basic conditions, and steel number 3 was prepared by hot rolling and trimming one side of a steel sheet edge at 100 mm, and the annealing temperature was 800 ° C. Steel No. 4 was subjected to nitriding treatment after annealing, so that the N content in the steel after nitriding was 0.0250%.

【００３１】各コイルより試験片を採取し下記測定を行
った。すなわち、圧延方向に板取したＪＩＳ５号引張試
験片による引張試験および直径５４mmの円形ブランクか
ら絞り加工で成形された直径３０mmの円筒カップにおけ
るイヤリング率により材質を測定した。イヤリング率は
カップのへり高さの最高値と最低値から（最高値−最低
値）／（最低値）により算出した。コイル内の測定位置
は長手位置としてコイル先端と終端のそれぞれ５，１０
ｍで各２点、ならびにコイル先端と終端の合計２０ｍを
除く長手の１／５毎の４点で合計８点、幅位置では両最
エッジ、幅の１／４，１／２，３／４の５点で合計４０
点とした。これらの鋼についての材質ばらつき（標準偏
差）を表２に示す。鋼番号２，６はＮ量の低い材料を用
いているために材質のばらつきが大きい。鋼番号３は鋼
番号２と同じ材料を用いているが、コイルエッジのトリ
ムや高温での焼鈍を実施したため材質偏差は小さくなっ
ているが、製造コストが高くなる。一方、本発明鋼１，
４，５では、製造条件によらず材質ばらつきが小さいこ
とが確認できる。Test pieces were taken from each coil and the following measurements were made. That is, the material was measured by a tensile test using a JIS No. 5 tensile test piece taken out in the rolling direction and an earring ratio in a cylindrical cup having a diameter of 30 mm formed by drawing from a circular blank having a diameter of 54 mm. The earring ratio was calculated from the maximum value and the minimum value of the edge height of the cup by (highest value-lowest value) / (lowest value). The measurement position in the coil is set to the longitudinal position as 5, 10,
m, 2 points each, and 4 points every 1/5 of the length excluding a total of 20 m of the coil tip and end, a total of 8 points, at the width position both extreme edges, 1/4, 1/2, 3/4 of the width 5 points for a total of 40
Points. Table 2 shows the material variation (standard deviation) of these steels. Steel Nos. 2 and 6 use a material with a low N content, and therefore have large variations in the material. Steel No. 3 uses the same material as Steel No. 2, but the material deviation is small due to the trimming of the coil edge and annealing at high temperature, but the manufacturing cost is high. On the other hand, steel 1 of the present invention
In Nos. 4 and 5, it can be confirmed that the material variation is small regardless of the manufacturing conditions.

【００３２】[0032]

【表１】 [Table 1]

【００３３】[0033]

【表２】 [Table 2]

【００３４】[0034]

【発明の効果】以上述べたごとく本発明によれば、従来
のような厳格な温度制御が不要で、かつ特殊な設備投資
も必要としないため高生産性かつ低コストで、コイル内
での材質が均一な薄手容器用素材を製造することができ
る。素材製造コストを抑え素材の薄手化メリットを無駄
なく生かした缶コストの低減が可能となる。As described above, according to the present invention, strict temperature control unlike the prior art is not required, and special equipment investment is not required. Can produce a uniform material for thin containers. It is possible to reduce the cost of material production and reduce the cost of cans by making full use of the advantage of thinner material.

───────────────────────────────────────────────────── フロントページの続き Ｆターム(参考） 4K032 AA01 AA04 AA16 AA21 AA27 AA29 AA31 BA01 CA03 CC04 CE01 CE02 CG02 CH04 CM01 4K037 EA01 EA04 EA05 EA15 EA18 EA23 EA25 EA27 EB02 EB06 EB08 FC04 FE01 FE02 FE03 FH01 FJ05 FM02 GA07 HA03 JA06  ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 4K032 AA01 AA04 AA16 AA21 AA27 AA29 AA31 BA01 CA03 CC04 CE01 CE02 CG02 CH04 CM01 4K037 EA01 EA04 EA05 EA15 EA18 EA23 EA25 EA27 EB02 EB06 FE08 FM03 FE08

Claims (4)

【特許請求の範囲】[Claims] 【請求項１】 重量％で、 Ｎ ：０．００４０〜０．０３００％、 Ａｌ：０．００５〜０．０８０％ を含有し、コイル内の材質ばらつき（標準偏差）が、Ｊ
ＩＳ５号引張り試験における０．２％耐力で２０ＭＰ
ａ、最高荷重で２０ＭＰａ以内であり、イヤリング率が
２．０％以内であることを特徴とする板厚０．４００mm
以下のコイル内材質の均質性に優れる極薄鋼板。1. The composition contains N: 0.0040 to 0.0300% and Al: 0.005 to 0.080% by weight, and the material variation (standard deviation) in the coil is J.
20MP at 0.2% proof stress in IS5 tensile test
a, the maximum load is within 20 MPa, and the earring ratio is within 2.0%.
Ultra-thin steel sheet with excellent homogeneity of the following coil materials. 【請求項２】 重量％で、Ｃ：０．０４００％以下を更
に含有することを特徴とする請求項１に記載の板厚０．
４００mm以下のコイル内材質の均質性に優れる極薄鋼
板。2. The sheet thickness according to claim 1, further comprising C: 0.0400% or less by weight%.
Ultra-thin steel sheet with excellent homogeneity of coil inner material of 400mm or less. 【請求項３】 重量％で、 Ｎ ：０．０４０〜０．０３００％、 Ａｌ：０．００５〜０．０８０％ を含有する鋼片を、熱間圧延を行うに際し、板幅中央部
の仕上温度を９３０℃以下とし、かつ仕上温度の幅中央
部と幅端部の差を２０℃以上とし、巻取り温度を７５０
℃以下２００℃以上とし、巻取り中の同一長手位置での
幅中央部の温度と幅端部の温度の差を３０℃以上とし、
巻取り中の幅中央部での長手中央の温度と長手先端又は
終端の温度の差を３０℃以上とし、熱延仕上板厚を３．
０mm以下とし、冷間圧延し、連続焼鈍し、Ｎの増加量が
板厚平均で２０〜３００ppm となるような窒化処理によ
り、Ｎ：０．０３００％以下とすることを特徴とする、
コイル内材質の均質性に優れる極薄鋼板の製造方法。3. A hot-rolled steel slab containing N: 0.040 to 0.0300% and Al: 0.005 to 0.080% by weight is finished at the center of the sheet width. The temperature is 930 ° C. or less, the difference between the width center and the width end of the finishing temperature is 20 ° C. or more, and the winding temperature is 750 °.
℃ or less and 200 ℃ or more, and the difference between the temperature at the center of the width and the temperature at the width end at the same longitudinal position during winding is 30 ℃ or more,
The difference between the temperature at the center of the width at the center of the width during winding and the temperature at the front end or the end of the length is 30 ° C. or more, and the hot-rolled finished plate thickness is 3.
0 mm or less, cold-rolled, continuously annealed, and nitridation treatment so that the increase in N is 20 to 300 ppm in average sheet thickness, N: 0.0300% or less,
A method for manufacturing ultra-thin steel sheets with excellent coil homogeneity. 【請求項４】 重量％で、Ｃを０．０４００％以下とす
ることを特徴とする請求項３記載のコイル内材質の均質
性に優れる極薄鋼板の製造方法。4. The method according to claim 3, wherein C is 0.0400% or less in terms of% by weight.