JPS6280224A - Manufacture of black plate for easy-opening lid - Google Patents

Abstract

PURPOSE:To manufacture a black plate for an easy-opening lid having superior suitability to forming into a lid and superior can opening properties by subjecting a continuously cast slab of a low carbon steel to hot rolling at a finishing temp. below the Ar3 transformation point, cold rolling, box annealing and skin pass rolling at a specified draft. CONSTITUTION:A continuously cast slab of a steel contg. <0.08wt% C, 0.05-0.50wt% Mn and 0.01-0.15wt% Al is hot rolled at a finishing temp. below the Ar3 transformation point to obtain a hot rolled soft plate having a large grain size. The plate is cold rolled as usual, box-annealed at the recrystallization temp. -750 deg.C and subjected to skin pass rolling at 5-30% draft. A black plate for an easy-opening can having superior suitability to forming into a lid by rivetting and other working and superior can opening properties is manufactured.

Description

【発明の詳細な説明】 （産業上の利用分野） 食缶、飲料缶用のイージーオープン蓋に供するぶりき又
はティンフリースチール原板（この明細書で単にぶりき
原板と呼ぶ）としての鋼板の使途適合に関しこの明細書
ではすぐれた開缶性および製蓋加工性を兼ねそなえるイ
ージーオープン蓋用のぶりき原板の製造方法についての
開発研究の成果を述べる。[Detailed Description of the Invention] (Industrial Application Field) Use of a steel plate as a tin or tin-free steel plate (simply referred to as a tin plate in this specification) for easy-open lids for food cans and beverage cans. With regard to suitability, this specification describes the results of research and development on a method for manufacturing a tin plate for easy-open lids that has excellent can-opening properties and lid-making processability.

イージーオープン蓋用材料としてはこれまで耐錆性、開
缶性の点からアルミニウムおよびその合金が主として使
われている。Up until now, aluminum and aluminum alloys have been mainly used as materials for easy-open lids because of their rust resistance and ease of can opening.

しかし食塩を含む内容物あるいは電解質の内容物の場合
、アルミニウム合金の一部使用によってガルバニック電
池（アルミニウム素地の露出部が陽極、ぶりき缶胴のピ
ンホール部が陰極）を形成し、電気化学的腐食が促進さ
れるため短時間のうちにアルミ蓋の穴あき発生につなが
る。したがってこのような場合は蓋用材料としてぶりき
又はティンフリースチールの使用が必要とされるわけで
ある。However, in the case of contents containing salt or electrolyte, a galvanic cell (the exposed part of the aluminum base is the anode and the pinhole part of the tin can body is the cathode) is formed by using a part of the aluminum alloy, and the electrochemical Corrosion is accelerated, leading to holes in the aluminum lid in a short period of time. Therefore, in such cases, it is necessary to use tinplate or tin-free steel as the lid material.

一方において空缶の廃′棄処分についての社会的な強い
要請に対する回収上の観点から缶材材が単一であること
が望ましい。On the other hand, from the viewpoint of recovery in response to strong social demands regarding the disposal of empty cans, it is desirable that the can stock be made of a single material.

そういった点から今後スティール製のイージーオープン
蓋（以下ＥＯＥと略す）の需要が高まることが予想され
る。From this point of view, it is expected that demand for steel easy-open lids (hereinafter abbreviated as EOE) will increase in the future.

（従来の技術） 従来ＩＥＯＥ用ぶりきとしては一般に７４−ＣＡと呼ば
れるＪＩＳ　Ｇ−３３０３に則るＴ４の調質度を有する
連続焼鈍材で製品の板厚が肌２２〜０．２６ｍｍのもの
が使用されてきた。しかるにこのぶりき製ＢＯＢの場合
ＡＩ製ＩＥＯＢに比べて開缶性がはるかに劣る。(Prior art) Conventional tinplate for IOE is a continuously annealed material with a heat treatment degree of T4 according to JIS G-3303, generally called 74-CA, and a product with a skin thickness of 22 to 0.26 mm. has been used. However, in the case of this tin BOB, the opening performance is far inferior to that of the AI made IEOB.

そこで開缶性の改善方法として析出炭化物を粗大化させ
てクラック起点を増加させる方法（詩興昭５５−６２１
４．２号公報）、高炭素材を素地鋼板中に微細なセメン
タイト粒子およびマルテンサイト粒子を均一分散させ開
缶時のボイド核生成の促進をはかる方法（特開昭６０−
２４３２８号公報）が提案されている。Therefore, as a method for improving can opening performance, there is a method of coarsening precipitated carbides and increasing the number of crack starting points (Shikosho 55-621).
4.2 Publication), a method in which fine cementite particles and martensite particles are uniformly dispersed in a base steel sheet using a high carbon material to promote void nucleation when opening a can (JP-A-60-1999).
24328) has been proposed.

（発明が解決しようとする問題点） 上記のような開缶性の改善策は、その反面リベット加工
性、耐衝撃性などに別の問題を派生してたとえばタブの
離脱や製品の輸送中のトラブル発生の懸念なしとしない
のであり、従ってリベット加工を含む製蓋性と開缶性の
両方を改善することがこの発明の目的である。(Problems to be Solved by the Invention) On the other hand, the above-mentioned measures to improve can openability may lead to other problems in riveting workability, impact resistance, etc., such as detachment of the tab or problems during transportation of the product. Therefore, it is an object of the present invention to improve both the lid-making properties including riveting and the can-opening properties.

（問題点を解決するための手段） 発明者らは上記の目的の充足のために種々実験検討を行
ってきた結果、以下の工程に従い有利に上記目的を達成
し得ることを３忍めた。(Means for Solving the Problems) As a result of various experimental studies conducted by the inventors in order to satisfy the above object, the inventors have found that the above object can be advantageously achieved by following the steps below.

つまりこの発明は、 Ｃ：　０．０８ｗｔ％以下、 Ｍｎ　：　０．０５〜０．５０ｗｔ％、Ａ１：０，０１
〜０．１５ｗｔ％、 残部実質的に鉄および不可避的不純物よりなる連続鋳造
スラブを、Ａｒｓ変態点以下の仕上温度で熱間圧延し、
ついで常法に従い冷間圧延を行った後、箱焼鈍法により
再結晶温度以上７５０℃以下の温度で焼鈍し、その後５
〜３０％の圧下率でスキンパスすることを特徴とするＥ
ＯＦ、用ぶりき原板の製造方法である。In other words, in this invention, C: 0.08wt% or less, Mn: 0.05 to 0.50wt%, A1: 0.01
~0.15 wt%, the balance substantially consisting of iron and unavoidable impurities, is hot rolled at a finishing temperature below the Ars transformation point,
Then, after performing cold rolling according to a conventional method, annealing is performed at a temperature above the recrystallization temperature and below 750°C by box annealing method, and then 5
E characterized by skin pass with a rolling reduction of ~30%
This is a method for producing tin plate originals for use in OF.

この発明においては、箱焼鈍後比較的高い圧下率のスキ
ンパスを施すことによりひずみをＩＩの中心部にまでお
よぼし、材質の均一性向上およびスコアー加工の際のス
コアー加工部の加工硬化を相対的に減じ開缶性の劣化を
防止するのである。In this invention, strain is applied to the center of II by performing a skin pass with a relatively high reduction rate after box annealing, thereby improving the uniformity of the material and relatively reducing work hardening of the scored part during score processing. This prevents deterioration in can opening performance.

（作　用） ここに素材ＣがＯ，Ｑ３ｗｔ％を超えると所望の調質度
を得るのに十分なスキンパス圧下率をかけることができ
なくなる。またカーバイドの増加によりスコアー加工部
の耐衝撃性に懸念が出てくるのでＣ含有量を０．３８ｗ
ｔ％以下に制限した。(Function) If the material C exceeds 3wt% of O,Q, it becomes impossible to apply a skin pass reduction rate sufficient to obtain the desired degree of heat treatment. In addition, due to the increase in carbide, there are concerns about the impact resistance of the score processed part, so the C content was reduced to 0.38w.
It was limited to t% or less.

Ｍｎは、不可避的不純物であるＳに起因する熱間脆性を
防止するため０．　Ｑ５ｗｔ％以上の含有が必要である
が、強度が増しすぎることを防止するため上限をＱ、　
５ｗｔ％とした。Mn is set to 0.00 to prevent hot embrittlement caused by S, which is an unavoidable impurity. It is necessary to contain Q5wt% or more, but to prevent the strength from increasing too much, the upper limit is set to Q,
It was set to 5wt%.

ＡＩについては脱酸に必要な０．０１％を下限とする含
有により連鋳時のブローホール等の発生を防ぐ必要があ
り一方Ａ１は高価なので過剰の添加は経済的に不利とな
るため０．１５％を上限とした。Regarding AI, it is necessary to prevent the occurrence of blowholes during continuous casting by limiting the content to 0.01%, which is necessary for deoxidation.On the other hand, since A1 is expensive, adding too much will be economically disadvantageous. The upper limit was set at 15%.

次にぶりき原板の熱延仕上温度は８３０℃以上の謂ゆる
高ＦＤＴとして微細均一な結晶粒径を得るのが通例であ
るがこの発明では １）できるだけ高いスキンパス圧下率を得るため、焼鈍
後の鋼板硬度を下げること、 ２）リベット加工性を含む製蓋加工性改善のため結晶粒
径を比較的大きなものとすること、の２つの目的からＡ
ｒ３変態点以下の温度で行い結晶粒径の大きな軟質な熱
延板を得るため、熱間圧延仕上温度を上記温度域とする
ことが不可欠である。Next, the hot-rolling finishing temperature of the tin plate is usually 830°C or higher, which is the so-called high FDT to obtain a fine and uniform crystal grain size. A.
In order to obtain a soft hot-rolled sheet with a large grain size by carrying out the hot rolling at a temperature below the r3 transformation point, it is essential that the hot rolling finishing temperature be within the above temperature range.

なお巻き取り温度については上記と同様の観点から、高
温が望ましいが６５０℃以上になると材質の幅方向の不
均一、炭化物の粗大化が発生し、種々問題が生じるので
６５０℃未満とすることがのぞましい。Regarding the winding temperature, from the same point of view as above, a high temperature is desirable, but if it exceeds 650°C, various problems such as non-uniformity in the width direction of the material and coarsening of carbides will occur, so it is not recommended to set it to less than 650°C. Delicious.

ついで常法による冷間圧延後箱焼鈍を採用する理由は、
連続焼鈍材にくらべて軟質な焼鈍後材質、そして大きな
結晶粒径が得られ易いというところにある。Next, the reason for adopting box annealing after cold rolling is as follows.
Compared to continuously annealed materials, it is easier to obtain a softer material after annealing and a larger crystal grain size.

焼鈍温度はその目的から再結晶温度以上とし、一方密着
などの操業トラブルを防止するためにその上限を７５０
　℃とした。For this purpose, the annealing temperature is set to be higher than the recrystallization temperature, while the upper limit is set at 750°C to prevent operational troubles such as adhesion.
℃.

次にスキンパスの圧下率は、ひずみを鋼板の中６部にま
でおよぼし材質の均一性向上およびスコアー加工の際の
スコアー加工部の加工硬化を相対的に減じて開缶性の劣
化を防止するためできるだけ大きくしたいが、種々製造
条件を調整しても圧下率３０％を超えるとそれによる加
工硬化過剰となり、リベット加工に支障をきたすので、
上限を３０％とした。一方スキンパスの圧下率下限につ
いては５％未満ではひずみの入り方が不十分であり、ス
コアー加工部の加工硬化が顕著となるばかりでなく肌荒
れ等の表面上の欠陥が出やすくなって、商品価値の低下
につながるので５％以上とした。Next, the rolling reduction rate of the skin pass is determined in order to apply strain to the middle 6 parts of the steel plate, improve the uniformity of the material, and relatively reduce work hardening of the score processed area during score processing to prevent deterioration of can openability. We want to make it as large as possible, but even if we adjust various manufacturing conditions, if the reduction rate exceeds 30%, it will cause excessive work hardening, which will interfere with riveting.
The upper limit was set at 30%. On the other hand, if the lower limit of the rolling reduction rate of the skin pass is less than 5%, the amount of strain introduced is insufficient, and not only will the work hardening of the score process become noticeable, but also surface defects such as rough skin will easily appear, resulting in product value. It was set at 5% or more because it leads to a decrease in

（実施例） 例１ 表−１に示す成分のＡ１キルド鋼を連続鋳造法によりス
ラブとなし、ＦＤＴを８５０℃、７６０℃の２水準とし
て、２．６ｍｍの熱延板をつくり、次で表−２に示す工
程で調質度Ｔ−４相当の発明材、比較材を製造した。(Example) Example 1 A1 killed steel with the components shown in Table 1 was made into a slab by continuous casting, and hot rolled sheets of 2.6 mm were made at two FDT levels of 850°C and 760°C. Inventive materials and comparative materials having a thermal refining degree of T-4 were manufactured in the process shown in -2.

製品板厚は０．２３ｍｍとした。これらの材料から５１
．５ｍｍφのＥＯＥを製造し、開缶性、リベット加工性
を評価した。なおスコアー残厚はすべて７０μｍに設定
した。評価結果を表３に示す。The product board thickness was 0.23 mm. 51 from these materials
．． EOEs with a diameter of 5 mm were manufactured, and their openability and rivet workability were evaluated. Note that the score residual thickness was all set to 70 μm. The evaluation results are shown in Table 3.

発明材でポツプ値が１．７ｋｇと従来にくらべて改善さ
れていることが明らかであり、その一方すベγト加工性
はリベット加工後のリベッ））ツブの直径で評価したと
ころ、管理目標範囲２．８ｍｍ以上に対し、発明材は２
．８８〜２．８９ｍｍで比較材の２．８２〜２．８５ｍ
ｍに比べてより良好な値を示して、リベット加工性が改
善されていることが明らかである。It is clear that the pop value of the invented material is 1.7 kg, which is improved compared to the conventional material.On the other hand, when the potability was evaluated by the diameter of the rivet after riveting, it was found that the control target was achieved. The invented material has a range of 2.8 mm or more.
．． 88-2.89mm and 2.82-2.85m of comparative material
It is clear that the riveting processability is improved by showing a better value than m.

なおこの試験でいずれの材料でも加工部の割れ等は生じ
なかった。In this test, no cracks or the like occurred in the processed parts of any of the materials.

（発明の効果） この発明によれば開缶性、製蓋性の必要性能を有利に充
足したＥＯＥ用ぶりき原板を簡便に製造できる。(Effects of the Invention) According to the present invention, it is possible to easily produce a tin plate for EOE that advantageously satisfies the required performance in terms of can-opening properties and lid-making properties.

Claims (1)

【特許請求の範囲】 １、Ｃ：０．０８ｗｔ％以下、 Ｍｎ：０．０５〜０．５０ｗｔ％、 Ａｌ：０．０１〜０．１５ｗｔ％、 残部実質的に鉄および不可避的不純物からなる連続鋳造
スラブを、Ａｒ＿３変態点以下の仕上温度で熱間圧延し
、ついで常法に従い冷間圧延を行った後、箱焼鈍により
再結晶温度以上７５０℃以下の温度で焼鈍し、その後５
〜３０％の圧下率でスキンパスする ことを特徴とするイージーオープン蓋用ぶりき原板の製
造方法。[Claims] 1. C: 0.08 wt% or less, Mn: 0.05 to 0.50 wt%, Al: 0.01 to 0.15 wt%, the remainder substantially consisting of iron and unavoidable impurities. The cast slab was hot rolled at a finishing temperature of Ar_3 transformation point or lower, then cold rolled according to a conventional method, and then annealed by box annealing at a temperature higher than the recrystallization temperature and lower than 750°C, and then 5
A method for manufacturing a tin plate for an easy-open lid, characterized by skin-passing at a rolling reduction of ~30%.