JP6198011B2 - Manufacturing method of steel plate for hard container - Google Patents
Manufacturing method of steel plate for hard container Download PDFInfo
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- AWJWCTOOIBYHON-UHFFFAOYSA-N furo[3,4-b]pyrazine-5,7-dione Chemical compound C1=CN=C2C(=O)OC(=O)C2=N1 AWJWCTOOIBYHON-UHFFFAOYSA-N 0.000 claims description 4
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 2
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- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical compound C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 description 1
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Landscapes
- Heat Treatment Of Sheet Steel (AREA)
Description
本発明は、硬質（高調質度）で加工性に優れ、かつ、時効硬化性を有する硬質容器用鋼板をバッチ焼鈍で製造する方法に関するものである。 The present invention is excellent in workability of a hard (harmonic quality level), and to a method for producing a steel plate for rigid containers having age-hardening properties in batch annealing.
ＪＩＳ Ｇ３３０３「ぶりき及びぶりき原板」や、ＪＩＳ Ｇ３３１５「ティンフリースチール」に規定される鋼板（容器用鋼板、缶用鋼板）は、その用途に要求される硬さに応じて調質度がＴ−１〜ＤＲ−１０（番号が小さい程、軟質であることを表す）に分類されている。このうち、調質度がＴ−１〜Ｔ−６の鋼板は、「低炭素鋼一回圧延」法、すなわち、低炭素鋼を一回冷間圧延した後、焼きなまし（再結晶焼鈍）することで、また、調質度がＤＲ−８〜ＤＲ−１０の鋼板は、「低炭素鋼二回圧延」法、すなわち、上記焼きなまし処理後の鋼板に二回目の冷間圧延をすることで製造すると規定されている。 Steel plates (steel plates for containers and steel plates for cans) specified in JIS G3303 “plates and tinplates” and JIS G3315 “tin-free steels” have a tempering degree according to the hardness required for their use. It is classified into T-1 to DR-10 (the smaller the number, the softer it is). Among these, the steel sheets having a tempering degree of T-1 to T-6 should be annealed (recrystallized annealing) after the cold rolling of the low carbon steel once, that is, the low carbon steel once rolling method. In addition, when the steel sheets having a tempering degree of DR-8 to DR-10 are manufactured by the “low carbon steel twice rolling” method, that is, by performing the second cold rolling on the steel sheet after the annealing treatment. It is prescribed.
上記「低炭素鋼一回圧延」法で製造される容器用鋼板のうち、軟質のＴ−１〜Ｔ−３の焼きなまし処理は、バッチ焼鈍炉ＢＡＦを用いた「バッチ焼鈍法（ボックス焼鈍）」で、また、硬質のＴ−４〜Ｔ−６の焼きなまし処理は、連続焼鈍ラインＣＡＬを用いた「連続焼鈍法」で施すのが一般的である。 Among the steel plates for containers manufactured by the above-mentioned “low rolling carbon steel” method, the annealing treatment of soft T-1 to T-3 is “batch annealing method (box annealing)” using a batch annealing furnace BAF. In addition, the hard annealing process of T-4 to T-6 is generally performed by a “continuous annealing method” using a continuous annealing line CAL.
ところで、近年、容器用鋼板の製造工程は、生産性を高める観点から、設備の連続化が進められており、その一環として、処理時間が長いバッチ焼鈍から高温・短時間で処理することができる連続焼鈍への切り替えが進められている。また、容器用鋼板の分野においては、ユーザーにおける材料コストの低減を図る観点から、硬質化（Ｔ−１〜Ｔ−３からＴ−４〜Ｔ−６への切り替え）による板厚低減（板厚０．２０ｍｍ未満）が積極的に進められている。その結果、連続焼鈍法で製造する容器用鋼板の比率は、近年、大きく上昇している。 By the way, in recent years, the manufacturing process of steel sheets for containers has been proceeding with continuation of equipment from the viewpoint of increasing productivity, and as part of this, processing can be performed at high temperature and in a short time from batch annealing with a long processing time. Switching to continuous annealing is underway. Also, in the field of steel plates for containers, from the viewpoint of reducing material costs for users, plate thickness reduction (plate thickness) by hardening (switching from T-1 to T-3 to T-4 to T-6) (Less than 0.20 mm) is being actively promoted. As a result, the ratio of steel plates for containers manufactured by a continuous annealing method has increased greatly in recent years.
しかし、硬質化や薄肉化、それに伴う連続焼鈍化は、鋼板の加工性の低下を招く。さらに、板厚の薄い鋼板を連続焼鈍法で製造することは、通板長の延長による生産性の低下を招くだけでなく、急速加熱、急速冷却に伴うヒートバックルや蛇行による板破断等の操業トラブルが発生し易く、安定生産することが難しくなるため、高度の通板技術が必要とされる。一方、バッチ焼鈍から連続焼鈍への切り替えに伴い、バッチ焼鈍炉の生産能力には余裕がある状態が続いている。そこで、硬質（高調質度）で、加工性に優れる容器用鋼板をバッチ焼鈍で製造する技術の開発が望まれている。 However, the hardening, thinning, and continuous annealing accompanying it cause a decrease in the workability of the steel sheet. Furthermore, manufacturing a thin steel plate by continuous annealing not only causes a decrease in productivity due to the extension of the plate length, but also operations such as heat buckle due to rapid heating and rapid cooling, and plate breakage due to meandering. Since trouble is likely to occur and stable production becomes difficult, advanced threading technology is required. On the other hand, with the switch from batch annealing to continuous annealing, the production capacity of the batch annealing furnace continues to have a margin. Then, development of the technique which manufactures the steel plate for containers which is hard (high quality) and excellent in workability by batch annealing is desired.
高強度化と薄肉化の両立を図る技術としては、先述した「低炭素鋼二回圧延」法がある。例えば、特許文献１には、低炭素鋼を素材とし、バッチ焼鈍することで、Ｔ−１からＤＲ−１０までの調質度の鋼板を製造する技術が提案されている。しかし、この方法は、Ｔ−４以上の硬さを得るためには、２回目の冷間圧延の圧下率を１５％以上とする必要があり、鋼板の延性低下が大きいため、加工性が要求される用途には使用できない。 As a technique for achieving both high strength and thinning, there is the aforementioned “low-carbon steel double rolling” method. For example, Patent Document 1 proposes a technique for manufacturing a steel sheet having a tempering degree from T-1 to DR-10 by using a low carbon steel as a raw material and performing batch annealing. However, in this method, in order to obtain a hardness of T-4 or more, it is necessary to set the reduction ratio of the second cold rolling to 15% or more, and the workability is required because the ductility of the steel sheet is greatly reduced. It cannot be used for the intended use.
また、特許文献２には、質量％で、Ｃ：０．０１８〜０．０６０％、Ｍｎ：０．２０〜０．３０％、Ａｌ：０．０２０〜０．０８０％、Ｎ：０．００３〜０．０１３％を含有する一次冷延後の鋼板を６００〜７００℃の温度範囲で２〜８時間保定するバッチ焼なまし炉による焼鈍（ＢＡＦ焼鈍）し、１〜２０％の二次冷延を行うことで、高強度かつ高ｒ値で、エキスパンド成形性に優れる３ピース缶用鋼板を製造する技術が提案されている。 Further, in Patent Document 2, in mass%, C: 0.018 to 0.060%, Mn: 0.20 to 0.30%, Al: 0.020 to 0.080%, N: 0.003 The steel sheet after primary cold rolling containing ˜0.013% is annealed (BAF annealing) in a batch annealing furnace that is held at a temperature range of 600 to 700 ° C. for 2 to 8 hours, followed by 1 to 20% secondary cooling. A technique for producing a steel plate for a three-piece can with high strength, high r value, and excellent expand formability by rolling is proposed.
しかしながら、上記特許文献１や特許文献２に提案された技術は、いずれも、二次冷延による生産性の低下やコストの上昇を招くため、容易に採用できないという問題がある。 また、上記技術では、バッチ焼鈍で鋼板を製造しているため、得られる鋼板は基本的に焼付硬化性を有さない。そのため、容器としての強度を確保する観点から、より高い調質度の鋼板が求められたり、板厚の低減が制限されたりするという問題もある。 However, any of the techniques proposed in Patent Document 1 and Patent Document 2 has a problem that it cannot be easily adopted because it causes a decrease in productivity and an increase in cost due to secondary cold rolling. Moreover, in the said technique, since the steel plate is manufactured by batch annealing, the steel plate obtained does not have bake hardenability fundamentally. Therefore, from the viewpoint of securing strength as a container, there is a problem that a steel sheet with a higher tempering degree is required or reduction of the plate thickness is limited.
本発明は、従来技術が抱える上記の問題点に鑑みてなされたものであり、その目的は、硬質（高調質度）で加工性に優れ、時効硬化性を有する容器用鋼板をバッチ焼鈍で安定して製造する方法を提案することにある。 The present invention, prior art suffer has been made in view of the above problems, and its object is excellent in workability of a hard (harmonic quality level), batch annealing the container steel sheet having age hardenable The purpose of this is to propose a stable manufacturing method.
発明者らは、上記の課題を解決するべく、素材となる低炭素鋼の成分組成と製造条件、特にバッチ焼鈍条件に着目して鋭意検討を重ねた。その結果、鋼素材のＡｌ含有量を高めることにより、バッチ焼鈍での浸窒を促進して固溶Ｎ量を所定量以上確保することで、硬質（高調質度）で加工性に優れるとともに時効硬化性を有する容器用鋼板を安定して製造することができことを見出し、本発明を開発するに至った。 In order to solve the above-mentioned problems, the inventors made extensive studies by paying attention to the component composition and production conditions of low-carbon steel as a raw material, particularly batch annealing conditions. As a result, by increasing the Al content of the steel material, nitriding in batch annealing is promoted to ensure a solid solution N amount of a predetermined amount or more, which is hard (high quality) and excellent in workability and aging. It discovered that the steel plate for containers which has curability could be manufactured stably, and came to develop this invention.
上記知見に基く本発明は、Ｃ：０．０２０〜０．０７０ｍａｓｓ％、Ｓｉ：０．０５ｍａｓｓ％以下、Ｍｎ：０．１０〜０．４０ｍａｓｓ％、Ｐ：０．０２０ｍａｓｓ％以下、Ｓ：０．０２０ｍａｓｓ％以下、Ａｌ：０．０５０〜０．２００ｍａｓｓ％を含有し、残部がＦｅおよび不可避的不純物からなる成分組成を有し、固溶Ｎ量が０．００５０ｍａｓｓ％以上で、硬さがＨＲ３０Ｔで５４以上である、バッチ焼鈍で製造された硬質容器用鋼板である。 The present invention based on the above-mentioned findings includes C: 0.020 to 0.070 mass%, Si: 0.05 mass% or less, Mn: 0.10 to 0.40 mass%, P: 0.020 mass% or less, S: 0.00. 020 mass% or less, Al: 0.050 to 0.200 mass%, the balance is composed of Fe and inevitable impurities, the solid solution N amount is 0.0050 mass% or more, and the hardness is HR30T It is the steel plate for hard containers manufactured by the batch annealing which is 54 or more.
本発明の上記硬質容器用鋼板は、２１０℃×２０分で時効後の硬さ上昇量がＨＲ３０Ｔで４以上であることを特徴とする。 The steel plate for a hard container of the present invention is characterized in that the amount of increase in hardness after aging at 210 ° C. × 20 minutes is 4 or more in HR30T.
また、本発明の上記硬質容器用鋼板は、上記成分組成に加えてさらに、Ｃｒ：０．０１〜０．１０ｍａｓｓ％、Ｔｉ：０．００５〜０．０５ｍａｓｓ％、Ｎｂ：０．００５〜０．０５ｍａｓｓ％、Ｖ：０．００５〜０．０５ｍａｓｓ％およびＺｒ：０．００５〜０．０５ｍａｓｓ％のうちから選ばれる１種または２種以上を含有することを特徴とする。 Moreover, in addition to the said component composition, the said steel plate for hard containers of this invention is further Cr: 0.01-0.10 mass%, Ti: 0.005-0.05mass%, Nb: 0.005-0. It contains one or more selected from 05 mass%, V: 0.005 to 0.05 mass%, and Zr: 0.005 to 0.05 mass%.
また、本発明の上記硬質容器用鋼板は、上記のいずれかに記載の鋼板の表面に電気めっきおよび／または電解クロム酸処理を施してなることを特徴とする。 Moreover, the said steel plate for hard containers of this invention is characterized by performing the electroplating and / or the electrolytic chromic acid process on the surface of the steel plate in any one of said.
また、本発明は、Ｃ：０．０２０〜０．０７０ｍａｓｓ％、Ｓｉ：０．０５ｍａｓｓ％以下、Ｍｎ：０．１０〜０．４０ｍａｓｓ％、Ｐ：０．０２０ｍａｓｓ％以下、Ｓ：０．０２０ｍａｓｓ％以下、Ａｌ：０．０５０〜０．２００ｍａｓｓ％、Ｎ：０．００２０〜０．０１５０ｍａｓｓ％を含有し、残部がＦｅおよび不可避的不純物からなる成分組成を有する冷間圧延板を、６００〜６８０℃×３〜１６ｈｒのバッチ焼鈍した後、伸び率が０．５〜２．０％の調質圧延を施す硬質容器用鋼板の製造方法において、上記バッチ焼鈍における雰囲気ガスを浸窒性として焼鈍後の鋼板中の固溶Ｎ量を０．００５０ｍａａｓｓ％以上とし、調質圧延後の鋼板の硬さをＨＲ３０Ｔで５４以上とすることを特徴とする請求項１〜３のいずれか１項に記載の硬質容器用鋼板の製造方法を提案する。 In the present invention, C: 0.020 to 0.070 mass%, Si: 0.05 mass% or less, Mn: 0.10 to 0.40 mass%, P: 0.020 mass% or less, S: 0.020 mass% Hereinafter, a cold-rolled sheet containing Al: 0.050-0.200 mass%, N: 0.0020-0.0150 mass%, with the balance being composed of Fe and unavoidable impurities, 600-680 ° C. In the manufacturing method of the steel plate for hard containers which performs the temper rolling whose elongation rate is 0.5 to 2.0% after batch annealing for 3 to 16 hours, the atmosphere gas in the batch annealing is set to be nitriding and after annealing. The solid solution N amount in the steel sheet is 0.0050 mass% or more, and the hardness of the steel sheet after temper rolling is 54 or more in HR30T. We propose a method for producing a rigid container for steel plate.
また、本発明の硬質容器用鋼板の製造方法は、上記雰囲気ガスとして、露点が−２０℃以下で、１〜１０ｖｏｌ％の水素ガスおよび５０ｖｏｌ％以上の窒素ガスを含有する浸窒性ガスを用いることを特徴とする。 Moreover, the manufacturing method of the steel plate for hard containers of this invention uses the nitriding gas which has a dew point of -20 degrees C or less and contains 1-10 vol% hydrogen gas and 50 vol% or more nitrogen gas as said atmosphere gas. It is characterized by that.
本発明によれば、加工性に優れ、しかも、硬質（高調質度）で時効硬化性を有する容器用鋼板を、バッチ焼鈍でも安定して製造することが可能となる。 ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to manufacture stably the steel plate for containers which is excellent in workability, and is hard (high quality) and has age-hardening property also by batch annealing.
まず、本発明の基本的技術思想について説明する。
調質度がＴ−４以上の硬質容器用鋼板をバッチ焼鈍で製造するときに用いる鋼については、従来、ＡＳＴＭに規定された、一般の食品容器に用いられるＭＲ型鋼にＰを添加したＭＣ型鋼や、上記ＭＲ型鋼やＭＣ型鋼にＮを添加したＮ型鋼が知られている（「ぶりきとティンフリー・スチール」東洋鋼鈑株式会社著、アグネ社発行、１９７４年５月１０日、ｐ．２１−２２）。
First, the basic technical idea of the present invention will be described.
About steel used when manufacturing steel plates for hard containers having a tempering degree of T-4 or more by batch annealing, MC type steel in which P is added to MR type steel used for general food containers, conventionally defined in ASTM. In addition, N type steels in which N is added to the above MR type steel and MC type steel are known (“Bukiki and Tin Free Steel” by Toyo Kohan Co., Ltd., published by Agne, May 10, 1974, p. 21-22).
しかし、Ｐは、鋼の強度や硬さを高める効果が大きい元素であるが、偏析を起こしやすく、また、容器用鋼板に求められる最も重要な特性である耐食性を低下させる元素でもある。そのため、Ｐを添加した鋼は現在では用いられていない。
また、Ｎは、連続焼鈍で鋼板を製造するときには、僅かな添加で鋼板の硬さを高めることができる有用な元素である。また、Ｎは、連続焼鈍のように高温から急冷する場合には、フェライト中に過飽和な固溶状態で存在するため、調質圧延後の時効硬化性（焼付硬化性）を高める効果がある。しかし、通常の製鋼設備では、０．０１５ｍａｓｓ％を超える窒素を鋼中に含有させるのは難しい。
However, P is an element that has a large effect of increasing the strength and hardness of steel, but is easily segregated, and is also an element that lowers corrosion resistance, which is the most important characteristic required for a steel plate for containers. Therefore, steel added with P is not used at present.
Further, N is a useful element that can increase the hardness of the steel sheet with a slight addition when the steel sheet is produced by continuous annealing. Further, N, when rapidly cooled from a high temperature like continuous annealing, is present in a supersaturated solid solution state in ferrite, and therefore has an effect of increasing age-hardening (bake hardenability) after temper rolling. However, it is difficult to contain more than 0.015 mass% of nitrogen in steel with ordinary steelmaking facilities.
ところで、食缶等に用いられる容器用鋼板は、優れた耐食性が要求されることから、鋼への含有が許容されている成分は少なく、上記ＰやＮ以外に鋼を強化（硬質化）する成分として挙げられるのはＳｉとＭｎしかない。しかし、ＳｉやＭｎの添加は、バッチ焼鈍で鋼板表面に濃化し、酸化膜を形成することによって、テンパーカラーと称される外観不良や、それに伴う耐食性の低下を引き起こすため、好ましくない。 By the way, since the steel plate for containers used for food cans etc. is required to have excellent corrosion resistance, there are few components allowed to be contained in steel, and the steel is strengthened (hardened) in addition to the above P and N. Only Si and Mn are listed as components. However, the addition of Si or Mn is not preferable because it concentrates on the surface of the steel sheet by batch annealing and forms an oxide film, thereby causing an appearance defect called temper color and a corresponding decrease in corrosion resistance.
そこで、発明者らは、容器用鋼板の素材（スラブ）の成分組成に加えて、製造条件にも着目して、鋼板の硬さを高める方法について検討を重ねた。その結果、鋼成分としてＡｌを従来よりも高めに添加し、バッチ焼鈍における浸窒を促進し、鋼板中のＮ含有量を高めることによってＡｌＮの析出量を高めることで高硬質化を図ることができること、また、上記バッチ焼鈍時に鋼板中に浸入し、Ａｌと結合せずに残った固溶Ｎ（フリーＮ）は、時効硬化性を有し、塗装・焼付後の硬さ（調質度）を高める効果を有することを見出し、本発明を開発するに至った。 Then, the inventors repeated examination about the method of raising the hardness of a steel plate paying attention also to manufacturing conditions in addition to the component composition of the raw material (slab) of the steel plate for containers. As a result, it is possible to increase the precipitation of AlN by increasing the precipitation amount of AlN by adding Al as a steel component higher than before, promoting nitriding in batch annealing, and increasing the N content in the steel sheet. In addition, solid solution N (free N) that penetrates into the steel sheet during the batch annealing and remains unbonded with Al has age-hardening properties, and hardness after coating and baking (tempering degree) As a result, the present invention has been developed.
次に、本発明に容器用鋼板の鋼素材の成分組成について説明する。
Ｃ：０．０２０〜０．０７０ｍａｓｓ％
Ｃは、鋼の強度に最も大きな影響を与える元素であり、バッチ焼鈍でＨＲ３０Ｔで５４以上の硬さを得るためには０．０２０ｍａｓｓ％以上含有させる必要がある。一方、Ｃ含有量が０．０７０ｍａｓｓ％を超えると、バッチ焼鈍時に鋼板表面にグラファイトが析出し、調質圧延時に光沢異常を引き起こすおそれがある。よって、Ｃは０．０２０〜０．０７０ｍａｓｓ％の範囲とする。好ましくは０．０３０〜０．０５０の範囲である。
Next, the component composition of the steel material of the steel plate for containers according to the present invention will be described.
C: 0.020-0.070 mass%
C is an element that has the greatest influence on the strength of the steel, and in order to obtain a hardness of 54 or more with HR30T by batch annealing, it is necessary to contain 0.020 mass% or more. On the other hand, if the C content exceeds 0.070 mass%, graphite may precipitate on the surface of the steel plate during batch annealing, which may cause abnormal gloss during temper rolling. Therefore, C is set to a range of 0.020 to 0.070 mass%. Preferably it is the range of 0.030-0.050.
Ｓｉ：０．０５ｍａｓｓ％以下
Ｓｉは、脱酸材として添加される元素であるが、鋼を固溶強化して硬さを高める元素でもある。しかし、多量に添加すると、スケール性の表面欠陥を引き起こしたり、バッチ焼鈍時に鋼板表面に濃化し、テンパーカラーを発生して外観を損ねたり、めっき性を阻害して耐食性を低下させたりする。よって、本発明では、Ｓｉは０．０５ｍａｓｓ％以下とする。好ましくは０．０２ｍａｓｓ％以下である。
Si: 0.05 mass% or less Si is an element added as a deoxidizing material, but is also an element that increases the hardness by solid solution strengthening of steel. However, if it is added in a large amount, it causes a scale-like surface defect, concentrates on the surface of the steel sheet during batch annealing, generates a temper color, impairs the appearance, or inhibits the plating property and lowers the corrosion resistance. Therefore, in this invention, Si shall be 0.05 mass% or less. Preferably it is 0.02 mass% or less.
Ｍｎ：０．１０〜０．４０ｍａｓｓ％
Ｍｎは、Ｓによる熱間脆性を防止し、熱間加工性を改善する元素である。また、Ｍｎは、固溶強化能があり、結晶粒を微細化し、硬さを高める効果もある。そこで、本発明では、Ｍｎを０．１０ｍａｓｓ％以上添加する。一方、Ｍｎは、０．４０ｍａｓｓ％を超えて過剰に添加すると、バッチ焼鈍時に鋼板表面に濃化してテンパーカラーを発生したり、耐食性を低下させたりする。よって、本発明では０．１０〜０．４０ｍａｓｓ％の範囲とする。好ましくは０．２４〜０．３５ｍａｓｓ％の範囲である。
Mn: 0.10 to 0.40 mass%
Mn is an element that prevents hot brittleness due to S and improves hot workability. Further, Mn has a solid solution strengthening ability, and has an effect of refining crystal grains and increasing hardness. Therefore, in the present invention, 0.10 mass% or more of Mn is added. On the other hand, if Mn exceeds 0.40 mass% and is added excessively, it concentrates on the surface of the steel sheet during batch annealing and generates a temper color or lowers the corrosion resistance. Therefore, in this invention, it is set as the range of 0.10-0.40 mass%. Preferably it is the range of 0.24-0.35 mass%.
Ｐ：０．０２０ｍａｓｓ％以下
Ｐは、鋼中に不可避的に混入してくる不純物元素であり、また、耐食性を低下させる元素でもあるため、できるだけ低減することが望ましい。よって、本発明では、Ｐは０．０２０ｍａｓｓ％以下とする。好ましくは０．０１６ｍａｓｓ％以下である。
P: 0.020 mass% or less P is an impurity element that is inevitably mixed in steel, and is also an element that lowers corrosion resistance. Therefore, in the present invention, P is 0.020 mass% or less. Preferably it is 0.016 mass% or less.
Ｓ：０．０２０ｍａｓｓ％以下
Ｓは、Ｐと同様、鋼中に不可避的に混入してくる不純物元素であり、鋼の熱間加工性を害したり、耐食性を低下させたりする有害元素でもある。よって、本発明では、Ｓは０．０２０ｍａｓｓ％以下とする。好ましくは０．００５ｍａｓｓ％以下である。
S: 0.020 mass% or less S, like P, is an impurity element that is inevitably mixed in steel, and is also a harmful element that impairs the hot workability of steel and reduces corrosion resistance. Therefore, in the present invention, S is 0.020 mass% or less. Preferably it is 0.005 mass% or less.
Ａｌ：０．０５０〜０．２００ｍａｓｓ％
Ａｌは、バッチ焼鈍において、鋼中のＮおよび浸窒したＮとＡｌＮを形成し、析出効果および細粒化効果を介して焼鈍後鋼板の硬さを高める効果を有する。さらに、発明者らの新規知見によれば、Ａｌは、雰囲気ガス中のＮの鋼板中への侵入（浸窒）を促進して固溶窒素量を増大し、時効硬化性を高める作用効果を有する。これらの効果を得るためには、Ａｌを０．０５０ｍａｓｓ％以上含有させる必要がある。しかし、０．２００ｍａｓｓ％を超える過剰な添加は、上記効果が飽和する他、再結晶温度を高めたり、粒成長を過度に阻害したりする。よって、本発明では、Ａｌは０．０５０〜０．２００ｍａｓｓ％の範囲とする。好ましくは０．０６０〜０．１００ｍａｓｓ％の範囲である。
Al: 0.050-0.200 mass%
Al has the effect of increasing the hardness of the steel sheet after annealing through the precipitation effect and the fine graining effect by forming N in the steel and nitrogen and AlN in the batch annealing. Furthermore, according to the inventors' new knowledge, Al promotes the penetration (nitrogenation) of N in the atmospheric gas into the steel sheet, thereby increasing the amount of dissolved nitrogen and improving the effect of age hardening. Have. In order to acquire these effects, it is necessary to contain Al 0.050 mass% or more. However, excessive addition exceeding 0.200 mass% saturates the above effect, raises the recrystallization temperature, and excessively inhibits the grain growth. Therefore, in the present invention, Al is in the range of 0.050 to 0.200 mass%. Preferably it is the range of 0.060-0.100 mass%.
Ｎ：０．００３０〜０．０１５０ｍａｓｓ％
Ｎは、上記Ａｌと結合して微細なＡｌＮを形成し、析出効果と細粒化効果により鋼板の硬さを高める効果がある。上記の効果を得るためには、０．００３０ｍａｓｓ％以上含有させる必要がある。しかし、容器用鋼板の通常の溶製条件において、０．０１５０ｍａｓｓ％を超えるＮを安定して鋼素材中に含有させるのは困難である。よって、Ｎは０．００３０〜０．０１５０ｍａｓｓ％の範囲とする。好ましくは０．００３〜０．０１０ｍａｓｓ％の範囲である。
N: 0.0030 to 0.0150 mass%
N combines with the Al to form fine AlN, and has the effect of increasing the hardness of the steel sheet due to the precipitation effect and the fine grain effect. In order to acquire said effect, it is necessary to contain 0.0030 mass% or more. However, it is difficult to stably contain N exceeding 0.0150 mass% in the steel material under normal melting conditions of the steel plate for containers. Therefore, N is set to a range of 0.0030 to 0.0150 mass%. Preferably it is the range of 0.003-0.010 mass%.
本発明の容器用鋼板の鋼素材は、上記必須とする成分の他には、バッチ焼鈍時における鋼板表面へのグラファイトの析出を抑制する目的で、Ｃｒ：０．０１〜０．１０ｍａｓｓ％、Ｔｉ：０．００５〜０．０５ｍａｓｓ％、Ｎｂ：０．００５〜０．０５ｍａｓｓ％、Ｖ：０．００５〜０．０５ｍａｓｓ％およびＺｒ：０．００５〜０．０５ｍａｓｓ％のうちから選ばれる１種または２種以上を含有することができる。特に、Ｃｒは、上記効果の他に、バッチ焼鈍における鋼板表面へのグラファイトの析出を抑制し、めっき後の耐食性を向上する効果があるので、添加するのが好ましい。 In addition to the essential components described above, the steel material of the steel plate for containers of the present invention is Cr: 0.01 to 0.10 mass%, Ti for the purpose of suppressing the precipitation of graphite on the steel plate surface during batch annealing. : 0.005 to 0.05 mass%, Nb: 0.005 to 0.05 mass%, V: 0.005 to 0.05 mass%, and Zr: 0.005 to 0.05 mass%, or one kind selected from Two or more kinds can be contained. In particular, Cr has the effect of suppressing the precipitation of graphite on the steel sheet surface during batch annealing and improving the corrosion resistance after plating, in addition to the above effects, so it is preferable to add Cr.
それらの効果は、Ｃｒは０．０１ｍａｓｓ％以上で、Ｔｉ，Ｎｂ，ＶおよびＺｒは、それぞれ０．００５ｍａｓｓ％以上の含有で得られる。一方、Ｃｒは０．１０ｍａｓｓ％超え、Ｔｉ，Ｎｂ，ＶおよびＺｒは、それぞれ０．０５ｍａｓｓ％超え含有すると、バッチ焼鈍時にテンパーカラーが発生し、表面品質や耐食性を損なうおそれがある。よって、Ｃｒ，Ｔｉ，Ｎｂ，ＶおよびＺｒを添加する場合には、上記範囲で添加するのが好ましい。より好ましくは、Ｃｒ：０．０１〜０．０５ｍａｓｓ％、Ｔｉ：０．００５〜０．０１ｍａｓｓ％、Ｎｂ：０．００５〜０．０１ｍａｓｓ％、Ｖ：０．００５〜０．０１ｍａｓｓ％およびＺｒ：０．００５〜０．０１ｍａｓｓ％の範囲である。 These effects are obtained when Cr is 0.01 mass% or more, and Ti, Nb, V and Zr are each contained 0.005 mass% or more. On the other hand, if Cr exceeds 0.10 mass% and Ti, Nb, V, and Zr each exceed 0.05 mass%, temper color is generated during batch annealing, which may impair the surface quality and corrosion resistance. Therefore, when adding Cr, Ti, Nb, V and Zr, it is preferable to add in the said range. More preferably, Cr: 0.01-0.05 mass%, Ti: 0.005-0.01 mass%, Nb: 0.005-0.01 mass%, V: 0.005-0.01 mass%, and Zr: It is the range of 0.005-0.01 mass%.
本発明の容器用鋼板の鋼素材における上記成分以外の残部は、Ｆｅおよび不可避的不純物である。ただし、本発明の効果を害しない範囲内であれば、他の元素の含有を拒むものではない。 The remainder other than the said component in the steel raw material of the steel plate for containers of this invention is Fe and an unavoidable impurity. However, as long as the effects of the present invention are not impaired, the inclusion of other elements is not rejected.
次に、本発明の容器用鋼板（製品板）の成分組成について説明する。
上記に説明した鋼素材中のＣ，Ｓｉ，Ｍｎ，Ｐ，ＳおよびＡｌは、通常の容器用鋼板の製造方法、製造条件であれば、鋼素材の組成のまま製品板となる。しかし、Ｎは、鋼素材の段階では不可避的封純物レベルの含有量であっても、バッチ焼鈍において、雰囲気ガス中に含まれる窒素が鋼中に浸入（浸窒）し、鋼中のフリーＡｌと結合してＡｌＮを形成し、析出効果と細粒化効果で鋼板の硬さを高める効果がある。
Next, the component composition of the steel plate for containers (product plate) of the present invention will be described.
C, Si, Mn, P, S, and Al in the steel material described above become a product plate with the composition of the steel material as long as it is a normal manufacturing method and manufacturing conditions for steel plates for containers. However, even if the N content is inevitable in the level of the sealed material at the stage of the steel material, in the batch annealing, nitrogen contained in the atmospheric gas penetrates into the steel (nitriding), and free in the steel. It combines with Al to form AlN, and has the effect of increasing the hardness of the steel sheet by the precipitation effect and the grain refining effect.
また、上記バッチ焼鈍時に鋼板中に浸入し、Ａｌと結合しなかったフリーなＮ（固溶Ｎ）は、容器製造時における塗装焼付工程で炭窒化物を形成して析出し、塗装焼付後の鋼板硬さを高める効果、いわゆる時効硬化能（焼付硬化性）を有する。ここで、上記時効硬化能は、本発明では、調質圧延後の鋼板に、２１０℃×２０ｍｉｎの時効処理を施した前後におけるＨＲ３０Ｔ硬さの上昇量で定義する。 In addition, free N (solid solution N) that penetrates into the steel sheet during the batch annealing and does not bond with Al is precipitated by forming carbonitrides in the coating baking process at the time of container manufacture, and after coating baking. It has the effect of increasing the steel sheet hardness, so-called age-hardening ability (bake hardenability). Here, in the present invention, the age-hardening ability is defined as an increase in HR30T hardness before and after the temper-rolled steel sheet is subjected to an aging treatment of 210 ° C. × 20 min.
発明者らの調査研究によれば、上記時効硬化能をＨＲ３０Ｔ硬さで４以上とするためには、バッチ焼鈍後の鋼板中の固溶Ｎ量は０．００５０ｍａｓｓ％（５０ｍａｓｓｐｐｍ）以上が必要であることが明らかとなっている。よって、本発明では、パッチ焼鈍後の固溶Ｎ量を０．００５０ｍａｓｓ％以上とする。より好ましくは０．００６０ｍａｓｓ％（６０ｍａｓｓｐｐｍ）以上である。ここで、調質圧延後の硬さが４上昇するということは、調質度が１つ上がることと同じである、即ち、調質圧延後の調質度がＴ−３の鋼板が、その後の焼付塗装における時効硬化で、調質度がＴ−４となることを意味する。 According to the research by the inventors, in order to make the age hardening capacity 4 or more in terms of HR30T hardness, the amount of solute N in the steel sheet after batch annealing needs to be 0.0050 mass% (50 massppm) or more. It is clear that there is. Therefore, in this invention, the amount of solute N after patch annealing shall be 0.0050 mass% or more. More preferably, it is 0.0060 mass% (60 massppm) or more. Here, increasing the hardness after temper rolling by 4 is the same as increasing the degree of tempering by 1, that is, after the temper rolling, the steel sheet having a tempering degree of T-3 is thereafter It means that the tempering degree becomes T-4 by age hardening in the baking coating.
次に、本発明の容器用鋼板の製造方法について説明する。
本発明の容器用鋼板の製造方法は、上記成分組成を有する鋼素材（スラブ）を熱間圧延し、冷間圧延し、浸窒処理を伴うバッチ焼鈍し、調質圧延して鋼板に所望の調質度を付与する方法である。
（鋼素材）
鋼素材の製造方法については、特に制限はないが、例えば、転炉や電気炉等で鋼を溶製し、取鍋処理や真空脱ガス処理等で上記成分組成を満たす鋼成分に調製した後、連続鋳造法あるいは造塊−分塊圧延法等で鋼素材（スラブ）とする方法が好ましい。なお、成分組成の均一性や、材質の均一性の観点からは、連続鋳造法を用いるのがより好ましい。
Next, the manufacturing method of the steel plate for containers of this invention is demonstrated.
The method for producing a steel plate for containers according to the present invention comprises hot rolling a steel material (slab) having the above component composition, cold rolling, batch annealing with nitriding treatment, and temper rolling to obtain a desired steel plate. This is a method of imparting a tempering degree.
(Steel material)
There are no particular restrictions on the method of manufacturing the steel material. For example, after the steel is melted in a converter or an electric furnace, the steel composition is prepared to satisfy the above composition by ladle processing, vacuum degassing processing, etc. A method of forming a steel material (slab) by a continuous casting method or an ingot-bundling rolling method is preferable. In addition, it is more preferable to use the continuous casting method from the viewpoint of the uniformity of the component composition and the uniformity of the material.
（熱間圧延）
上記鋼素材（スラブ）は、その後、熱間圧延して熱延板とするが、上記熱間圧延は、上記スラブを１０５０〜１３００℃の温度に再加熱した後、仕上圧延終了温度をＡｒ３変態点以上として行うのが望ましい。
上記スラブの再加熱温度が１０５０℃未満では、変形抵抗（圧延負荷）が増大して熱間圧延するのが難しくなったり、上記仕上圧延終了温度を確保することが困難となったりする。一方、スラブの再加熱温度が１３００℃を超えると、スケールロスが大きくなったり、表面疵が発生したりするようになるので好ましくない。
また、熱間圧延における仕上圧延終了温度がＡｒ３変態点未満となると、熱延後の結晶粒が粗大化して、材質不良や形状不良を引き起こすおそれがある。ただし、仕上圧延終了温度が高過ぎると、スケール起因の表面欠陥が発生するようになるので、上限は１０００℃程度とするのが好ましい。
なお、上記熱間圧延は、上記仕上圧延終了温度を確保できる限り、連続鋳造後の高温スラブを、再加熱することなく、そのまま連続して行ってもよい。
(Hot rolling)
Thereafter, the steel material (slab) is hot-rolled to form a hot-rolled sheet. In the hot-rolling, after the slab is reheated to a temperature of 1050 to 1300 ° C., the finish rolling finish temperature is set to Ar 3. It is desirable to carry out at or above the transformation point.
When the reheating temperature of the slab is less than 1050 ° C., deformation resistance (rolling load) increases and it becomes difficult to perform hot rolling, or it becomes difficult to ensure the finish rolling finishing temperature. On the other hand, if the reheating temperature of the slab exceeds 1300 ° C., the scale loss becomes large or surface flaws occur, which is not preferable.
In addition, when the finish rolling finish temperature in hot rolling is less than the Ar 3 transformation point, the crystal grains after hot rolling are coarsened, which may cause a material defect or a shape defect. However, if the finish rolling finish temperature is too high, surface defects due to scale will occur, so the upper limit is preferably about 1000 ° C.
In addition, as long as the said finish rolling completion temperature can be ensured, the said hot rolling may be continuously performed as it is, without reheating the high temperature slab after continuous casting.
上記熱間圧延のコイル巻取温度は、４５０〜７５０℃の範囲とするのが好ましい。巻取温度が４５０℃未満では、鋼板の形状が悪化するおそれがある。一方、７５０℃を超えると、鋼板表面に生成するスケールが厚くなり、酸洗性に悪影響を及ぼしたり、鋼板表層の結晶粒を粗大化させたりするので好ましくない。 The coiling temperature of the hot rolling is preferably in the range of 450 to 750 ° C. If the winding temperature is less than 450 ° C., the shape of the steel sheet may be deteriorated. On the other hand, when the temperature exceeds 750 ° C., the scale formed on the surface of the steel sheet becomes thick, which adversely affects the pickling property and coarsens the crystal grains of the steel sheet surface layer.
（冷間圧延）
上記熱間圧延後の鋼板は、その後、酸洗し、冷間圧延して所定の板厚の冷延板とする。
上記冷間圧延における圧下率は、常法に準じて決定すればよく、特に制限はないが、加工性や異方性を改善する観点から、７０〜９８％の範囲とするのが好ましい。
(Cold rolling)
The hot-rolled steel sheet is then pickled and cold-rolled to obtain a cold-rolled sheet having a predetermined thickness.
The rolling reduction in the cold rolling may be determined according to a conventional method and is not particularly limited. However, from the viewpoint of improving workability and anisotropy, the rolling reduction is preferably in the range of 70 to 98%.
（バッチ焼鈍）
上記冷間圧延後の鋼板は、その後、６００℃以上６８０℃以下の温度で３〜１６ｈｒ均熱保持するバッチ焼鈍を施す。ここで、本発明がバッチ焼鈍を採用する理由は、バッチ焼鈍時に雰囲気ガス中のＮを鋼板中に浸窒させ、鋼中のＡｌと結合し、微細なＡｌＮを析出させることにより、硬質の容器用鋼板を得るためである。
また、バッチ焼鈍における均熱温度を６００℃以上６８０℃以下とする理由は、６００℃未満では、再結晶が不完全となり、組織も不均一となって、均質な材質と優れた加工性を得ることが難しくなるおそれがあるほか、浸窒が十分に進行しないため、析出するＡｌＮ量が不足して硬質化が不十分となったり、固溶窒素量が不足して所定の時効硬化能が得られなくなったりするからである。一方、均熱温度が６８０℃を超えると、セメンタイトが粗大化して延性の低下を招く。また、鋼板表面へのＣ，Ｓｉ，Ｍｎ等の濃化や析出が著しくなり、テンパーカラーが発生したり、耐食性を阻害したりし、さらには、焼鈍時に鋼板の焼付きが生じるようになるので好ましくない。
また、均熱時間を３〜１６ｈｒとする理由は、３ｈｒ未満では再結晶が十分に進行せず、組織も不均一となって、均質な材質と優れた加工性を得ることが難しくなるとともに、浸窒が不十分となり、上記した硬質化が不足したり、所期した時効硬化能が得られなかったりするからである。一方、均熱時間が１６ｈｒを超えると、結晶粒が粗大化して鋼板が軟質化し、本発明の目的である硬質の鋼板が得られなくなるからである。好ましい焼鈍温度は６１０〜６５０℃の範囲、均熱時間は６〜１０ｈｒの範囲である。
(Batch annealing)
Thereafter, the steel sheet after the cold rolling is subjected to batch annealing that is maintained at a temperature of 600 ° C. or higher and 680 ° C. or lower for 3 to 16 hours. Here, the reason why the present invention adopts batch annealing is to harden the container by nitriding N in the atmosphere gas into the steel plate during batch annealing, bonding with Al in the steel, and precipitating fine AlN. This is to obtain a steel plate.
In addition, the reason for setting the soaking temperature in batch annealing to 600 ° C. or more and 680 ° C. or less is that if it is less than 600 ° C., recrystallization becomes incomplete and the structure becomes non-uniform, and a homogeneous material and excellent workability are obtained. In addition, since nitriding does not proceed sufficiently, the amount of precipitated AlN is insufficient and hardening becomes insufficient, or the amount of solid solution nitrogen is insufficient and the prescribed age hardening capacity is obtained. It is impossible to do so. On the other hand, when the soaking temperature exceeds 680 ° C., cementite is coarsened and ductility is lowered. In addition, the concentration and precipitation of C, Si, Mn, etc. on the steel sheet surface become significant, temper color is generated, corrosion resistance is impaired, and further, the steel sheet is seized during annealing. It is not preferable.
In addition, the reason for setting the soaking time to 3 to 16 hr is that recrystallization does not proceed sufficiently if the duration is less than 3 hr, the structure becomes non-uniform, and it becomes difficult to obtain a homogeneous material and excellent workability. This is because the nitriding becomes insufficient and the above-mentioned hardening is insufficient, or the desired age-hardening ability cannot be obtained. On the other hand, when the soaking time exceeds 16 hours, the crystal grains become coarse and the steel plate becomes soft, and the hard steel plate that is the object of the present invention cannot be obtained. A preferable annealing temperature is in the range of 610 to 650 ° C., and the soaking time is in the range of 6 to 10 hr.
ここで、本発明の製造方法において重要なことは、前述したように、このバッチ焼鈍において、焼鈍雰囲気ガス中の窒素を鋼板中に浸窒させ、鋼中のＡｌと結合させてＡｌＮを析出させるとともに、焼鈍後の鋼板中の固溶Ｎ量を０．００３０ｍａｓｓ％以上として、時効硬化能を確保することである。 Here, what is important in the production method of the present invention is that, as described above, in this batch annealing, nitrogen in the annealing atmosphere gas is nitrided in the steel sheet and is combined with Al in the steel to precipitate AlN. At the same time, the amount of solute N in the steel sheet after annealing is set to 0.0030 mass% or more to ensure age hardening.
上記の浸窒を起こさせるためには、バッチ焼鈍における雰囲気ガスを浸窒性とする必要がある。上記の浸窒性ガスとしては、露点が−２０℃以下で、Ｈ２：１〜１０ｖｏｌ％、Ｎ２：５０ｖｏｌ％以上を含有し、残部：不活性ガス（０ｖｏｌ％も含む）からなる混合ガスを用いるのが好ましい。 In order to cause the above nitriding, it is necessary to make the atmospheric gas in batch annealing nitriding. Examples of the immersion窒性gas, a dew point is -20 ° C. or less, H 2: 1~10vol%, N 2: containing more than 50 vol%, the balance: mixed gas comprising an inert gas (including 0 vol%) Is preferably used.
（調質圧延）
上記バッチ焼鈍後の鋼板は、その後、形状矯正や表面粗度の付与、機械的特性の改善（降伏伸びの消失、調質度の調整、歪時効性の付与）等を目的として調質圧延（スキンパス）を施し、容器用鋼板（原板）とする。
ここで、本発明において重要なことは、上記調質圧延の伸び率を０．５％以上２．０％以下の範囲に制限することである。伸び率が０．５％未満では、上記調質圧延の効果を確実に得ることが難しい。一方、調質圧延の伸び率を２．０％以上とすると、鋼板の延性低下や異方性の増大を招き、本発明が所期した加工性を確保することが難しくなる。そこで、本発明においては、２．０％を上限とする。ただし、硬さ（調質度）を重視し、加工性がそれほど要求されない用途向けの鋼板に対しては、調質圧延の伸び率を本発明の範囲より高めて製造してもよいことは勿論である。
(Temper rolling)
The steel sheet after batch annealing is then temper-rolled for the purposes of shape correction, surface roughness, mechanical property improvement (disappearance of yield elongation, adjustment of tempering degree, imparting strain aging), etc. A skin pass is applied to make a steel plate for containers (original plate).
Here, what is important in the present invention is to limit the elongation of the temper rolling to a range of 0.5% to 2.0%. If the elongation is less than 0.5%, it is difficult to reliably obtain the effect of the temper rolling. On the other hand, if the elongation of temper rolling is 2.0% or more, the ductility of the steel sheet is reduced and the anisotropy is increased, and it becomes difficult to ensure the workability expected by the present invention. Therefore, in the present invention, the upper limit is 2.0%. However, for steel sheets for applications where the hardness (tempering degree) is emphasized and workability is not so much required, it is of course possible to produce the temper rolling with a higher elongation than the scope of the present invention. It is.
（表面処理）
上記のようにして得た容器用鋼板の原板は、その後、電気めっきライン等に通板して電気めっき処理を施して、例えば、電気錫めっき処理を施してＪＩＳ Ｇ３３０３に規定の「ぶりき」や、電解クロム酸処理を施して金属クロムとクロム水和酸化物の２層からなるＪＩＳ Ｇ３３１５に規定の「ティンフリースチール」等の容器用鋼板とすることができる。なお、上記電気めっき処理は、上記電気錫めっき処理や電解クロム酸処理に限定されるものではない。また、本発明の容器用鋼板の原板は、上記電気めっき処理を施すことなく、塗装を施して塗装鋼板として用いてもよいし、無処理（原板）のまま使用してもよく、特に制限はない。
(surface treatment)
The container steel plate obtained as described above is then passed through an electroplating line or the like and subjected to electroplating treatment, for example, subjected to electrotin plating treatment, and `` Grip '' defined in JIS G3303. Alternatively, a steel plate for containers such as “Tin Free Steel” defined in JIS G3315, which is formed of two layers of metallic chromium and chromium hydrated oxide, can be obtained by performing electrolytic chromic acid treatment. The electroplating process is not limited to the electrotin plating process or the electrolytic chromic acid process. Moreover, the original plate of the steel plate for containers of the present invention may be used as a coated steel plate without being subjected to the above-described electroplating treatment, or may be used as it is without treatment (original plate). Absent.
表１に示したＡ〜Ｆの成分組成を有する鋼素材（スラブ）を連続鋳造法で製造し、１１５０℃の温度に再加熱した後、仕上圧延終了温度ＦＤＴを９００℃、巻取温度ＣＴを６１０℃とする熱間圧延により板厚が２．３ｍｍの熱延板とし、酸洗して鋼板表面のスケールを除去した後、１回の冷間圧延で板厚が０．２０２ｍｍ（圧下率９１％）の冷延板とした。
次いで、上記冷延板に、バッチ焼鈍炉で表２に示した条件で再結晶焼鈍を施した後、表２に示した伸び率の調質圧延を施してぶりき原板とした。その後、上記ぶりき原板を電気錫めっきラインＥＴＬに通板し、錫付着量が２．８ｇ／ｍ２の電気錫めっきを両面に施してぶりき製品板とした。
A steel material (slab) having the composition of A to F shown in Table 1 is manufactured by a continuous casting method, reheated to a temperature of 1150 ° C., finish rolling finish temperature FDT is 900 ° C., and winding temperature CT is A hot-rolled sheet having a thickness of 2.3 mm is formed by hot rolling at 610 ° C., pickled to remove the scale on the surface of the steel sheet, and then the thickness is reduced to 0.202 mm (reduction rate of 91 by one cold rolling). %) Cold-rolled sheet.
Next, the cold-rolled sheet was subjected to recrystallization annealing in the batch annealing furnace under the conditions shown in Table 2, and then subjected to temper rolling with the elongation shown in Table 2 to obtain a tinplate original sheet. Thereafter, the tin plate was passed through an electric tin plating line ETL, and electrotin plating with a tin adhesion amount of 2.8 g / m 2 was applied on both sides to obtain a tin plate product plate.
斯くして得たぶりき製品板からサンプルを採取し、以下の評価試験に供した。
＜固溶窒素量の測定＞
上記の各サンプルから分析用試料を採取し、めっき層を除去した後、不活性ガス中で上記試料を加熱・融解して試料中の窒素をＮ２として抽出・分離した後、熱伝導度検出器で全窒素量を定量し、次いで、電解臭素メタノール分解法（湿式Ｎ分析）で析出物（窒化物）を形成している窒素量を定量し、全窒素量から析出窒素量を差し引いて固溶窒素量を求めた。
＜調質圧延後の硬さ評価＞
上記の各サンプルについて、めっき後（時効前）の硬さＨＲ３０Ｔを測定し、硬さがＨＲ３０Ｔで５４以上を硬さ良（○）、５４未満を硬さ不良（×）と評価した。
＜時効硬化性の評価＞
上記の各サンプルについて、２１０℃×２０ｍｉｎの時効処理を施した後の硬さＨＲ３０Ｔを測定し、調質圧延後（時効処理前）の硬さとの差から時効硬化性を評価した。具体的には、ＨＲ３０Ｔ硬さの上昇量が６以上を時効硬化性優（◎）、６未満から４以上を時効硬化性良（○）、４未満を時効硬化性劣（×）と評価し、優（◎）と良（○）を合格とした。
＜耐錆性の評価＞
上記の各サンプルから４０ｍｍ×８０ｍｍの耐食試験片を採取し、乾燥状態（温度２５℃、相対湿度５０％）と湿潤状態（温度５０℃、相対湿度９８％）を３０分ごとに繰り返す乾湿繰り返し試験を９６時間実施し、試験片表面に発生した点錆の個数から、試験片の片面当たりの点錆の発生個数が５０個以下を耐錆性良（○）、５１個以上を耐錆性不良（×）と評価し、良（○）を合格とした。
＜加工性の評価＞
上記の各サンプルから、直径１００ｍｍφの円形ブランクを５枚ずつ打ち抜き、２ピース缶の缶胴の絞り加工を模擬した、絞り率が０．６の１次絞り後、絞り率が０．７５の２次絞り加工を行い、上記絞り加工における破断発生率（（破断数／全加工数）×１００％）が０．５％以下を加工性が良（○）、０．５％超えを加工性が不良（×）と評価し、良（○）を合格とした。
A sample was taken from the tinplate product plate thus obtained and subjected to the following evaluation test.
<Measurement of the amount of dissolved nitrogen>
Samples for analysis are collected from each of the above samples, the plating layer is removed, the sample is heated and melted in an inert gas, and nitrogen in the sample is extracted and separated as N 2 , followed by thermal conductivity detection. Quantify the total amount of nitrogen with a vessel, then quantitate the amount of nitrogen that forms precipitates (nitrides) by electrolytic bromine methanol decomposition (wet N analysis), subtract the amount of precipitated nitrogen from the total amount of nitrogen The amount of dissolved nitrogen was determined.
<Hardness evaluation after temper rolling>
About each said sample, hardness HR30T after metal-plating (before aging) was measured, hardness was HR30T and 54 or more were evaluated as hardness hardness ((circle)), and less than 54 evaluated hardness hardness (x).
<Evaluation of age hardening>
About each said sample, hardness HR30T after performing aging treatment of 210 degreeC x 20 min was measured, and age-hardening property was evaluated from the difference with the hardness after temper rolling (before aging treatment). Specifically, an HR30T hardness increase of 6 or more was evaluated as age-hardening excellent (◎), less than 6 to 4 or more as age-hardening good (◯), and less than 4 as age-hardening poor (×). Excellent (◎) and Good (○) were accepted.
<Evaluation of rust resistance>
A 40 mm x 80 mm corrosion-resistant test piece is taken from each of the above samples, and a dry / wet repeat test that repeats a dry state (temperature 25 ° C., relative humidity 50%) and a wet state (temperature 50 ° C., relative humidity 98%) every 30 minutes. For 96 hours. From the number of spot rust generated on the surface of the test piece, the number of spot rust generated on one side of the test piece is 50 or less, good rust resistance (○), and 51 or more is poor rust resistance. (×) was evaluated, and good (◯) was determined to be acceptable.
<Evaluation of workability>
Five round blanks with a diameter of 100 mmφ were punched out from each of the above samples, and after the first drawing with a drawing ratio of 0.6, simulating drawing of a two-piece can body, a drawing ratio of 2 was 0.75. The next drawing process is performed, and the fracture occurrence rate ((number of fractures / total number of processes) × 100%) in the above drawing process is 0.5% or less, the workability is good (◯), and the processability exceeds 0.5%. It was evaluated as defective (x), and good (◯) was determined as acceptable.
上記評価試験の結果を表１に併記した。
この結果から、本発明に適合した条件で製造した発明例の鋼板は、バッチ焼鈍で製造しているにも拘わらず、ＨＲ３０Ｔが５４以上で、かつ、加工性や耐食性に優れ、しかも、優れた時効硬化性を有していることがわかる。
The results of the evaluation test are also shown in Table 1.
From this result, although the steel plate of the inventive example manufactured under the conditions suitable for the present invention is manufactured by batch annealing, HR30T is 54 or more, and excellent in workability and corrosion resistance, and excellent It turns out that it has age-hardening property.
本発明の鋼板は、容器用に限定されるものではなく、例えば、家電製品や電子機器の部材用にも用いることができ、特に制限はない。 The steel plate of the present invention is not limited to containers, and can be used for members of household appliances and electronic devices, for example, and is not particularly limited.
Claims (5)
Ｓｉ：０．０５ｍａｓｓ％以下、
Ｍｎ：０．１０〜０．４０ｍａｓｓ％、
Ｐ：０．０２０ｍａｓｓ％以下、
Ｓ：０．０２０ｍａｓｓ％以下、
Ａｌ：０．０５０〜０．２００ｍａｓｓ％および
Ｎ：０．００２０〜０．０１５０ｍａｓｓ％を含有し、
残部がＦｅおよび不可避的不純物からなる成分組成を有する冷間圧延板を、６００〜６８０℃×３〜１６ｈｒのバッチ焼鈍した後、伸び率が０．５〜２．０％の調質圧延を施す硬質容器用鋼板の製造方法において、
上記バッチ焼鈍における雰囲気ガスを浸窒性として焼鈍後の鋼板中の固溶Ｎ量を０．００５０ｍａａｓｓ％以上とし、調質圧延後の鋼板の硬さをＨＲ３０Ｔで５４以上とすることを特徴とする硬質容器用鋼板の製造方法。 C: 0.020-0.070 mass%,
Si: 0.05 mass% or less,
Mn: 0.10 to 0.40 mass%,
P: 0.020 mass% or less,
S: 0.020 mass% or less,
Al: 0.050-0.200 mass% and N: 0.0020-0.0150 mass%,
A cold-rolled sheet having a component composition consisting of Fe and inevitable impurities as a balance is subjected to batch annealing at 600 to 680 ° C. for 3 to 16 hours, and then subjected to temper rolling with an elongation of 0.5 to 2.0%. In the method of manufacturing a steel plate for a hard container,
The atmosphere gas in the batch annealing is nitriding, the solid solution N amount in the steel plate after annealing is 0.0050 mass% or more, and the hardness of the steel plate after temper rolling is 54 or more in HR30T. method of manufacturing a hard quality container for steel plate that.
Ｃｒ：０．０１〜０．１０ｍａｓｓ％、Cr: 0.01-0.10 mass%,
Ｔｉ：０．００５〜０．０５ｍａｓｓ％、Ti: 0.005-0.05 mass%,
Ｎｂ：０．００５〜０．０５ｍａｓｓ％、Nb: 0.005 to 0.05 mass%,
Ｖ：０．００５〜０．０５ｍａｓｓ％およびV: 0.005-0.05 mass% and
Ｚｒ：０．００５〜０．０５ｍａｓｓ％のうちから選ばれる１種または２種以上を含有することを特徴とする請求項１〜３のいずれか１項に記載の硬質容器用鋼板の製造方法。The method for producing a steel plate for a hard container according to any one of claims 1 to 3, comprising one or more selected from Zr: 0.005 to 0.05 mass%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN112126858B (en) * | 2020-09-18 | 2021-12-07 | 唐山瑞丰钢铁（集团）有限公司 | Cold-rolled steel for USB electronic component and production method thereof |
| KR102493773B1 (en) * | 2020-12-21 | 2023-01-30 | 주식회사 포스코 | Steel sheet having high phospatability and manufacturing method of the same |
| KR102493772B1 (en) * | 2020-12-21 | 2023-01-30 | 주식회사 포스코 | Cold-rolled steel sheet having high phosphating properties and manufacturing method the same |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPS5194414A (en) * | 1975-02-18 | 1976-08-19 | FUKASHIBORIKANYOBURIKIGENBANNO SEIZOHOHO | |
| JPS6280224A (en) * | 1985-10-02 | 1987-04-13 | Kawasaki Steel Corp | Manufacture of black plate for easy-opening lid |
| JPS637336A (en) * | 1986-06-27 | 1988-01-13 | Nippon Steel Corp | Production of extra-thin steel sheet for welded can having excellent flanging property |
| JPH0759734B2 (en) * | 1989-04-07 | 1995-06-28 | 新日本製鐵株式会社 | Low carbon aluminum killed cold-rolled steel sheet excellent in workability, surface roughening property and earring property, and method for producing the same |
| JPH03236446A (en) * | 1990-02-09 | 1991-10-22 | Kawasaki Steel Corp | Steel sheet for two-piece can |
| JPH03285044A (en) * | 1990-03-30 | 1991-12-16 | Kawasaki Steel Corp | Manufacture of steel sheet for three-piece can and three-piece can |
| JP2002239646A (en) * | 2001-02-21 | 2002-08-27 | Kawasaki Steel Corp | Method of manufacturing special shaped can |
| JP5000452B2 (en) * | 2007-10-18 | 2012-08-15 | 新日本製鐵株式会社 | Steel plate for 3-piece can with high strength and excellent expand formability and manufacturing method thereof |
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