JP2001286927A - Method of manufacturing hot-rolled steel plate - Google Patents
Method of manufacturing hot-rolled steel plateInfo
- Publication number
- JP2001286927A JP2001286927A JP2000103335A JP2000103335A JP2001286927A JP 2001286927 A JP2001286927 A JP 2001286927A JP 2000103335 A JP2000103335 A JP 2000103335A JP 2000103335 A JP2000103335 A JP 2000103335A JP 2001286927 A JP2001286927 A JP 2001286927A
- Authority
- JP
- Japan
- Prior art keywords
- hot
- steel sheet
- steel plate
- rolled steel
- scale
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Metal Rolling (AREA)
- Shaping Metal By Deep-Drawing, Or The Like (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、熱延鋼板の表面酸
化スケールを、酸洗処理を行わずに、熱間圧延ラインの
インラインにて除去し、巻き取り前に塑性加工一般に用
いられる所定の潤滑剤を塗布し、鋼板自体に潤滑性を持
たせた、深絞り性の良い熱延鋼板の製造法に関するもの
である。BACKGROUND OF THE INVENTION The present invention relates to a method for removing the surface oxide scale of a hot-rolled steel sheet in-line in a hot rolling line without performing a pickling treatment, and performing a plastic working process before winding. The present invention relates to a method for producing a hot-rolled steel sheet having good deep drawability, in which a lubricant is applied to impart lubricity to the steel sheet itself.
【０００２】[0002]
【従来の技術】熱間圧延ラインにおいて、熱延鋼板は、
スラブ加熱後、粗圧延および仕上圧延で圧延された鋼板
ストリップをホットランテーブル上で冷却し、巻取機で
コイルにして製造される。スラブ加熱で生成したスラブ
の厚い酸化スケールは、粗圧延前および仕上げ圧延前に
高圧水によるスケールブレーカーで除去されるが、仕上
げスタンドから巻取機までの工程で鋼板表面には酸化ス
ケールが生成する。製造された熱延鋼板は、冷延鋼板の
素材となるほか、熱延製品として各種用途に加工され
る。いずれの場合も鋼板表面に酸化スケールがあると、
冷延時あるいは各種用途への加工時に鋼板表面およびロ
ールや工具の疵発生の原因となるので、スケール除去が
行われている。従来の熱延鋼板のスケール除去は、熱間
圧延後の連続酸洗ラインを通板し、塩酸や硫酸を使用す
る酸洗処理によって行われる。また酸洗速度を向上させ
るため、曲げやブラスト処理などの機械的処理を併用す
ること、さらには酸洗時に電気化学処理を施すことも行
われる。そしてその後、デスケーリングをされた鋼板は
プレス加工や深絞り加工などの二次加工を施される。こ
の時、塑性加工を行う際に金型や工具などに潤滑剤を塗
布し、加工負荷を軽減させ、焼き付きやかじりおよびし
わ等を生じないようにしている。2. Description of the Related Art In a hot rolling line, a hot-rolled steel sheet is
After the slab is heated, the steel strip, which has been rolled by rough rolling and finish rolling, is cooled on a hot run table, and is manufactured into a coil by a winder. Thick oxide scale of slab generated by slab heating is removed by high-pressure water scale breaker before rough rolling and finish rolling, but oxide scale is generated on the steel sheet surface in the process from finishing stand to winder . The manufactured hot-rolled steel sheet is used as a material for cold-rolled steel sheet, and is also processed as a hot-rolled product for various uses. In any case, if there is oxide scale on the steel sheet surface,
During cold rolling or processing for various uses, it causes the generation of scratches on the surface of the steel sheet, rolls, and tools, so scale removal is performed. Conventional scale removal of hot-rolled steel sheets is performed by a pickling process using hydrochloric acid or sulfuric acid through a continuous pickling line after hot rolling. Further, in order to improve the pickling speed, mechanical treatment such as bending or blasting is used in combination, and further, electrochemical treatment is performed at the time of pickling. After that, the descaled steel sheet is subjected to secondary processing such as pressing and deep drawing. At this time, when performing plastic working, a lubricant is applied to a mold, a tool, or the like to reduce the working load and prevent seizure, galling, wrinkles, and the like.
【０００３】[0003]
【発明が解決しようとする課題】まず、上記のような従
来の熱延鋼板のスケール除去は、鋼材製造メーカーや一
部の鋼材ユーザーで行われるが、酸洗処理を伴うため、
酸洗槽およびその周辺設備や関進設備の保全、酸洗廃液
の処理などに要するコストが増大している。今後、環境
問題などにより廃酸処理はますます厳しく、その処理コ
ストの高騰は避け難い課題となつている。−方、近年に
おける熱延素材の品質向上や熱延鋼板製造技術の向上に
伴って、材質および表面性状の優れた熱延鋼板が製造で
きるようになり、従来は冷延鋼板が使用されていた分野
に薄手の熱延鋼板が使用され始め、その用途はますます
拡大することが予想される。First, the scale removal of the conventional hot-rolled steel sheet as described above is carried out by a steel material manufacturer or some steel material users.
Costs required for preserving the pickling tank and its peripheral equipment and related equipment, and for treating pickling waste liquid are increasing. In the future, waste acid treatment will become more severe due to environmental problems and the like, and soaring treatment costs will be an unavoidable issue. -In recent years, with the improvement of hot rolled material quality and hot rolled steel sheet manufacturing technology in recent years, it has become possible to manufacture hot rolled steel sheets with excellent materials and surface properties, and conventionally cold rolled steel sheets were used Thin hot-rolled steel sheets have begun to be used in the field, and their applications are expected to expand further.
【０００４】そこで本発明が解決しようとする課題は、
熱延鋼板の表面酸化スケールを除去するにあたり、従来
のような熱間圧延後の酸洗ラインに通板せず、熱間圧延
ラインにおいて圧延終了後に存在する表面酸化スケール
を、熱間圧延ラインのインラインにて酸洗処理を行わず
に除去し、なおかつインラインにて塑性加工に用いられ
る所定の潤滑剤を塗布し、鋼板自体に潤滑性を持たせ、
深絞り性の良い熱延鋼板を製造することにある。The problem to be solved by the present invention is
In removing the surface oxide scale of the hot-rolled steel sheet, without passing through the pickling line after the conventional hot rolling, the surface oxide scale present after the end of the rolling in the hot rolling line, the hot rolling line Removed without performing in-line pickling treatment, and apply a predetermined lubricant used for plastic working in-line to give the steel plate itself lubricity,
An object of the present invention is to produce a hot-rolled steel sheet having good deep drawability.
【０００５】[0005]
【課題を解決するための手段】本発明は、鋼板の熱間圧
延ラインあるいは粗圧延設備と仕上げ圧延設備との間で
先行圧延材の尾端部と後行圧延材の先端部を接合し熱間
圧延するラインにおいて、最終仕上げ圧延機とピンチロ
ール間で還元性雰囲気を通板させることにより、鋼板表
面の酸化スケールを還元除去することを特徴とする熱延
鋼板の製造方法であり、前記記載の還元性雰囲気の組成
が水素５％以上、残部が不活性ガスあるいはＮ2 ガスか
らなることを特徴とする熱延鋼板の製造方法である。ま
た、還元性雰囲気を通板させた後、非酸化性雰囲気中で
冷却および／または焼鈍することを特徴とする熱延鋼板
の製造方法であり、前記記載の非酸化性の雰囲気の組成
が不活性ガスあるいはＮ2 ガス１００％とすることを特
徴とする熱延鋼板の製造方法であり、ピンチロールと巻
き取り前に塑性加工用として用いられる所定の潤滑剤を
塗布することにより自己潤滑性をもった鋼板とすること
を特徴とする熱延鋼板の製造方法であり、前記記載の各
熱間圧延方法によって得られた熱延鋼板を深絞り加工を
施してなる缶製品である。SUMMARY OF THE INVENTION According to the present invention, a hot rolling line or a rough rolling facility and a finishing rolling facility for a steel sheet are joined by joining the tail end of the preceding rolled material and the leading end of the succeeding rolled material. In a hot rolling steel sheet, a hot rolled steel sheet is produced by passing a reducing atmosphere between a final finishing mill and a pinch roll to reduce and remove oxide scale on the steel sheet surface. Wherein the composition of the reducing atmosphere is 5% or more of hydrogen and the balance is made of an inert gas or N 2 gas. Further, a method for producing a hot-rolled steel sheet characterized by cooling and / or annealing in a non-oxidizing atmosphere after passing through a reducing atmosphere, wherein the composition of the non-oxidizing atmosphere is not sufficient. A method for producing a hot-rolled steel sheet characterized by using 100% active gas or N 2 gas. The self-lubricating property is obtained by applying a pinch roll and a predetermined lubricant used for plastic working before winding. A method for producing a hot-rolled steel sheet, characterized in that the hot-rolled steel sheet obtained by each of the above-described hot rolling methods is subjected to deep drawing.
【０００６】即ち、本発明は、鋼板の熱間圧延ラインに
おいて、最終圧延後の通板中の鋼板を水素ガス含有雰囲
気中を通板し、巻き取り前に潤滑剤を塗布することを持
微とする熱延鋼板の製造方法であり、そして、前記通板
中の鋼板を非酸化性雰囲気中で冷却および／または焼鈍
することが好ましい。[0006] That is, the present invention is characterized in that, in a hot rolling line for a steel sheet, the steel sheet after the final rolling is passed through an atmosphere containing hydrogen gas and a lubricant is applied before winding. It is preferable to cool and / or anneal the steel sheet in the passing sheet in a non-oxidizing atmosphere.
【０００７】[0007]
【発明の実施の形態】鋼板の熱間圧延ラインにおいて、
仕上圧延後の鋼板ストリップは、ホットランテーブル上
を搬送されつつ冷却され、巻取機で巻き取られてコイル
となる。本発明法はこのような熱間圧延ラインにおい
て、仕上圧延機で最終圧延された通板中の熱延鋼板を水
素ガス含有雰囲気中を通板することで、鋼板表面の酸化
スケールを還元除去する。BEST MODE FOR CARRYING OUT THE INVENTION In a steel sheet hot rolling line,
The steel strip after the finish rolling is cooled while being conveyed on a hot run table, and wound by a winder to form a coil. The method of the present invention reduces and removes oxide scale on the surface of the steel sheet by passing the hot-rolled steel sheet in the finally rolled steel sheet in a hydrogen gas-containing atmosphere in a hot rolling line in such a hot rolling line. .
【０００８】熱間圧延ラインで生成する鋼板表面の酸化
スケールは鉄酸化物を主体とするものであり、水素で還
元されて鉄となる。この還元反応は温度が高いほど速
く、本発明者が実験の結果、熱間圧延ラインにおける仕
上最終圧延後の鋼板温度５００〜９００℃では、この段
階での厚さ１〜３μｍ程度の酸化スケールが１〜１０秒
以内の短時間で十分に還元除去できた。The oxide scale on the surface of the steel sheet generated in the hot rolling line is mainly composed of iron oxide, and is reduced by hydrogen to iron. This reduction reaction is faster as the temperature is higher, and as a result of experiments by the present inventor, at a steel sheet temperature of 500 to 900 ° C. after finishing and final rolling in a hot rolling line, an oxide scale having a thickness of about 1 to 3 μm at this stage is formed. Reduction and removal could be sufficiently performed in a short time within 1 to 10 seconds.
【０００９】従来、鉄酸化物のスケールが水素雰囲気で
還元されることはよく知られていたものの、処理ライン
を通板中に還元除去できる表面酸化スケールは、処理時
間および処理温度と還元速度から判断すると、厚さが
０．１μｍ以下の極めて薄いものとされていた。したが
って従来は、厚さが１μｍ以上もある熱延鋼板の表面酸
化スケールを、水素ガス含有雰囲気で還元除去するには
極めて長い時間を必要とし、熱間圧延ラインのインライ
ン処理で行うことは実用的には不可能と考えられてい
た。Conventionally, it has been well known that iron oxide scale is reduced in a hydrogen atmosphere. However, a surface oxide scale that can be reduced and removed while a processing line is being passed through a processing line requires a processing time, a processing temperature, and a reduction rate. As a result, it was determined that the thickness was extremely thin, 0.1 μm or less. Therefore, conventionally, it takes a very long time to reduce and remove the surface oxide scale of a hot-rolled steel sheet having a thickness of 1 μm or more in an atmosphere containing hydrogen gas, and it is practical to perform the in-line treatment in a hot rolling line. Was considered impossible.
【００１０】ところが本発明者が実験検討の結果、実際
の熱間圧延ラインで圧延された仕上最終圧延後の鋼板の
表面酸化スケールは、厚さが１μｍ以上であるにもかか
わらず、水素ガス含有雰囲気中を通板することで上記の
ように短時間で還元除去でき、インラインでのスケール
除去が可能であることが判明した。以下にその実験結果
について説明する。However, as a result of experimental studies by the present inventor, the surface oxide scale of the steel sheet after finishing and final rolling, which has been rolled in an actual hot rolling line, has a hydrogen gas content even though the thickness is 1 μm or more. It has been found that by passing through the atmosphere, reduction and removal can be performed in a short time as described above, and scale removal can be performed in-line. Hereinafter, the experimental results will be described.
【００１１】図１は、熱間圧延により生成した鋼板の表
面酸化スケールを、水素濃度２５％、残部Ｎ2 ７５％の
雰囲気で還元したときの、還元温度とスケール除去に必
要な還元所要時間の関係を示したものである。この図か
らわかるように、還元温度が高いほど還元所要時間は短
縮する。また、スケール厚さが増すと還元所要時間が長
くなるが、還元温度８００℃以上では、スケール厚さ
１．５μｍと３μｍではほとんど変わらず１秒程度で還
元除去できる。FIG. 1 shows the reduction temperature and the reduction time required for scale removal when the surface oxide scale of a steel sheet produced by hot rolling is reduced in an atmosphere having a hydrogen concentration of 25% and a balance of N 2 of 75%. It shows the relationship. As can be seen from this figure, the higher the reduction temperature, the shorter the required reduction time. In addition, the reduction time becomes longer as the scale thickness increases, but at a reduction temperature of 800 ° C. or higher, the reduction can be removed in about 1 second with almost no change at the scale thickness of 1.5 μm and 3 μm.
【００１２】図２は、図１における厚さ３μｍのスケー
ルについて、還元温度８００℃で、雰囲気の水素濃度と
還元所要時間との関係を示し、水素濃度５％以上では、
濃度に関係なく１秒程度で還元除去できることがわか
る。よって、還元性雰囲気の水素濃度を５％以上とし
た。５％未満では還元時間が長くなり設備上困難なため
である。FIG. 2 shows the relationship between the hydrogen concentration in the atmosphere and the time required for reduction at a reduction temperature of 800 ° C. for the 3 μm thick scale in FIG.
It can be seen that reduction and removal can be performed in about 1 second regardless of the concentration. Therefore, the hydrogen concentration in the reducing atmosphere was set to 5% or more. If it is less than 5%, the reduction time will be long and equipment will be difficult.
【００１３】以上の実験結果と、表面酸化スケールおよ
びその還元過程の観察結果から、熱間圧延後の鋼板の表
面酸化スケールが水素含有雰囲気で還元される過程につ
いて、図３および図４のスケッチ図により説明する。図
３（ａ）は厚さが１μｍ未満の酸化スケールの還元前の
伏態であり、地鉄１の表面にスケール層２が存在する。
図３（ｂ）は還元初期段階の状態であり、スケール層２
は水素ガスと接触する表面から還元されて、表層が還元
鉄層３で覆われる。そしてスケール層２の還元反応が終
了すると、図３（ｃ）に示すように地鉄１が還元鉄層３
で覆われる。From the above experimental results and the observation results of the surface oxide scale and the reduction process thereof, the process of reducing the surface oxide scale of the hot-rolled steel sheet in a hydrogen-containing atmosphere is shown in FIGS. 3 and 4. This will be described below. FIG. 3A shows an oxide scale having a thickness of less than 1 μm before reduction, and a scale layer 2 is present on the surface of the base iron 1.
FIG. 3B shows the state of the initial stage of the reduction, and the scale layer 2
Is reduced from the surface in contact with hydrogen gas, and the surface layer is covered with the reduced iron layer 3. When the reduction reaction of the scale layer 2 is completed, as shown in FIG.
Covered with.
【００１４】これに対してスケール層２の厚さが１μｍ
以上の場合は、図４（ａ）に示すように、還元前のスケ
ール層２は１μｍ未満の場合と変わらないが、還元初期
段階では、図４（ｂ）に示すように、スケール層２は表
面が還元鉄層３で覆われているほか、図３（ｂ）の場合
と異なり、スケール層２の内部には厚さ方向のクラック
４が観察され、クラック４に沿って還元鉄５が観察され
る。これは、厚さ１μｍ以上のスケール層２は、水素ガ
スに接触する表面から還元されて還元鉄層３が生成し、
還元による体積減少に伴って還元鉄層３の厚さがある限
界を超えると、図４（ｂ）のように厚さ方向にクラック
４が発生し、クラック４が新たな表面となって、スケー
ル層２と水素ガスとの反応が進行するためと考えられ
る。On the other hand, the thickness of the scale layer 2 is 1 μm.
In the above case, as shown in FIG. 4A, the scale layer 2 before reduction is not different from the case of less than 1 μm, but in the initial stage of reduction, as shown in FIG. In addition to the surface being covered with the reduced iron layer 3, unlike the case of FIG. 3B, cracks 4 in the thickness direction are observed inside the scale layer 2, and reduced iron 5 is observed along the cracks 4. Is done. This is because the scale layer 2 having a thickness of 1 μm or more is reduced from the surface in contact with the hydrogen gas to generate the reduced iron layer 3,
When the thickness of the reduced iron layer 3 exceeds a certain limit due to the reduction in volume due to reduction, cracks 4 are generated in the thickness direction as shown in FIG. It is considered that the reaction between the layer 2 and the hydrogen gas proceeds.
【００１５】したがって、厚さが１μｍ以上の酸化スケ
ールを有する場合でも、スケールと水素ガスとの反応面
積が増大して、インライン処理可能な短時間でスケール
が還元除去される。なお、上記図１および図２の実験結
果から、還元温度は８００℃以上、水素ガス濃度は５％
以上とするのが好ましい。還元反応が終了すると、図４
（ｃ）に示すように、地鉄１の表面は還元鉄層３で覆わ
れ、還元鉄層３内にはクラック４が観察される。Therefore, even when the oxide scale has a thickness of 1 μm or more, the reaction area between the scale and the hydrogen gas is increased, and the scale is reduced and removed in a short time that allows in-line processing. From the experimental results of FIGS. 1 and 2, the reduction temperature is 800 ° C. or higher and the hydrogen gas concentration is 5%.
It is preferable to make the above. When the reduction reaction is completed, FIG.
As shown in (c), the surface of the ground iron 1 is covered with the reduced iron layer 3, and cracks 4 are observed in the reduced iron layer 3.
【００１６】上記のような鋼板表面の酸化スケールの還
元除去は、熱間圧延ラインのホットランテーブルを走行
中の鋼板ストリップに対して行うことができる。例え
ば、ホットランテーブルに走行中のストリップを覆う保
定炉を設け、該保定炉中の雰囲気を水素ガス含有雰囲気
にすればよい。また、鋼板温度が５７０℃を超える温度
域では酸化スケールの生成速度が速いので、鋼板ストリ
ップが大気に触れる際の温度は５７０℃以下とすること
により、還元除去後のスケール生成を防止する。上記保
定炉などによる水素ガス含有雰囲気を出るときの鋼板温
度が酸化しやすい温度になる場合は、非酸化性雰囲気中
で冷却する。The reduction of oxide scale on the surface of the steel sheet as described above can be performed on the steel sheet strip running on the hot run table of the hot rolling line. For example, a holding furnace for covering the running strip may be provided on the hot run table, and the atmosphere in the holding furnace may be a hydrogen gas-containing atmosphere. Further, since the generation rate of the oxide scale is high in the temperature range where the steel sheet temperature exceeds 570 ° C., the temperature at which the steel sheet strip comes into contact with the atmosphere is set to 570 ° C. or less, thereby preventing scale formation after reduction and removal. When the temperature of the steel sheet at the time of exiting the hydrogen gas-containing atmosphere by the above-mentioned holding furnace or the like becomes a temperature at which oxidation is likely to occur, cooling is performed in a non-oxidizing atmosphere.
【００１７】本発明法により得られた熱延鋼板は、上記
のような過程で表面の酸化スケールが還元され、鋼板表
面にはクラックを含む還元鉄層が形成されている。この
ような過程を経て形成された鉄の層は、不純物の固溶や
析出物が極めて少ないので、耐食性にも優れている。In the hot-rolled steel sheet obtained by the method of the present invention, the oxide scale on the surface is reduced in the above process, and a reduced iron layer containing cracks is formed on the steel sheet surface. Since the iron layer formed through such a process has very few impurities in solid solution and precipitates, it has excellent corrosion resistance.
【００１８】通常の鋼には、原料および精錬過程で不可
避的な不純物が含まれ、Ｆｅよりも卑な元素であるＡ１
やＳｉ等が固溶していると、腐食環境でのＦｅの溶出速
度が速くなって耐食性が低下する。またＭｎＳ、Ａｌ
Ｎ、ＴｉＮ、ＴｉＣ、ＮｂＮ、ＮｂＣなどの析出物が表
面に存在すると、析出物を陽極とし、鋼表面を陰極とす
るミクロ的な局部電池の形成により腐食が促進される。
ところが、酸化スケールは主としてＦｅの外方拡散によ
り成長し、上記のような鋼中の不純物成分はスケール中
にはほとんど含有されないので、このスケールを還元し
て形成される還元鉄層は、不純物の固溶や析出物が極め
て少なくなる。[0018] Ordinary steel contains raw materials and impurities inevitable in the refining process.
If Si or Si is dissolved in solid solution, the elution rate of Fe in a corrosive environment increases, and the corrosion resistance decreases. MnS, Al
When precipitates such as N, TiN, TiC, NbN, and NbC are present on the surface, corrosion is promoted by the formation of a microscopic local battery having the precipitates as an anode and the steel surface as a cathode.
However, the oxide scale grows mainly by outward diffusion of Fe, and the impurity component in steel as described above is hardly contained in the scale. Therefore, the reduced iron layer formed by reducing this scale has Solid solution and precipitates are extremely reduced.
【００１９】また、還元後巻き取り前に該熱延鋼板に所
定の潤滑剤を塗布することによって、鋼板中のクラック
に潤滑剤が含浸され、自己潤滑性を持たせることができ
る。したがって、本発明法により自己潤滑性を有する鋼
板が得られる。また、前記理由にて耐食性にも優れた鋼
板が得られる。Further, by applying a predetermined lubricant to the hot-rolled steel sheet after the reduction and before the winding, cracks in the steel sheet can be impregnated with the lubricant and have self-lubricating properties. Therefore, a steel sheet having self-lubricating properties can be obtained by the method of the present invention. Further, for the above-mentioned reason, a steel sheet excellent in corrosion resistance can be obtained.
【００２０】次に、熱延鋼板が冷延鋼板のような加工用
に使用される場合、熱間圧延後に焼鈍を行って再結晶組
織にする必要がある。この焼鈍も、仕上最終圧延後、イ
ンラインにてホットランテーブル上で行うことができ
る。この場合は、仕上げ最終圧延後、水素ガス雰囲気で
酸化スケールを還元除去したのち、引き続き非酸化性雰
囲気で焼鈍することもでき、また水素含有雰囲気でスケ
ール還元と焼鈍を同時に行うこともできる。ここで非酸
化性雰囲気の組成としては不活性ガスあるいはＮ 2 ガス
１００％が好ましい。Next, the hot-rolled steel sheet is used for processing like a cold-rolled steel sheet.
When used for hot rolling, annealing is performed to recrystallize
Need to weave. This annealing is also performed after the final rolling.
Can be performed on a hot run table in line
You. In this case, after finishing the final rolling, in a hydrogen gas atmosphere
After reducing and removing the oxide scale,
Annealing can be performed in an atmosphere.
The reduction and annealing can be performed simultaneously. Where the non-acid
The composition of the oxidizing atmosphere may be inert gas or N2. Twogas
100% is preferred.
【００２１】[0021]
【実施例】（実施例１）熱間圧延ラインにおいて、仕上
圧延終了後の低炭素鋼熱延鋼帯を、本発明法によりイン
ラインにてスケール除去した。図５に示すように、粗圧
延後の熱延鋼帯６を高圧水デスケーリング装置７により
スケール除去した後、仕上圧延機８にて板厚２．０mmに
圧延し、引続きホットランテーブル上にて還元性雰囲気
炉９に通板して酸化スケールを還元除去した。還元性雰
囲気炉９に入る直前の鋼帯１の温度はα域あるいはγ域
であり、保定炉９内は水素ガス５％窒素ガス９５％の雰
囲気とし、炉内の通板時間は１．２秒間であった。得ら
れた鋼板の表面には肉眼的にはテンパーカラー状の酸化
スケールが認められなかった。EXAMPLES (Example 1) In a hot rolling line, a low-carbon steel hot-rolled steel strip after finishing rolling was scale-removed in-line by the method of the present invention. As shown in FIG. 5, the hot-rolled steel strip 6 after the rough rolling is descaled by a high-pressure water descaling device 7, and is then rolled to a thickness of 2.0 mm by a finishing mill 8, and subsequently on a hot run table. The scale was passed through a reducing atmosphere furnace 9 to reduce and remove the oxide scale. The temperature of the steel strip 1 immediately before entering the reducing atmosphere furnace 9 is in the α range or the γ range. Seconds. Temper color oxide scale was not visually observed on the surface of the obtained steel sheet.
【００２２】（実施例２）熱間圧延ラインにおいて、仕
上圧延終了後の低炭素鋼熱延鋼帯を、本発明法によりイ
ンラインにてスケール除去した。図５に示すように、粗
圧延後の熱延鋼帯６を高圧水デスケーリング装置７によ
りスケール除去した後、仕上圧延機８にて板厚２．０mm
に圧延し、引続きホットランテーブル上にて還元性雰囲
気炉９に通板して酸化スケールを還元除去し、ピンチロ
ールと巻き取り前に潤滑剤（１００％合成エステル）を
塗布した。還元性雰囲気炉９に入る直前の鋼帯６の温度
はα域あるいはγ域であり、保定炉９内は水素ガス５％
窒素ガス９５％の雰囲気とし、炉内の通板時間は１．２
秒間であった。得られた鋼板の表面には肉眼的にはテン
パーカラー状の酸化スケールが認めらず、この鋼板を深
絞り加工を施したところ、潤滑剤が塗布されていたた
め、深絞り加工は行えた。(Example 2) In a hot rolling line, a low-carbon steel hot-rolled steel strip after finish rolling was scale-removed in-line by the method of the present invention. As shown in FIG. 5, after the hot-rolled steel strip 6 after the rough rolling is scale-removed by a high-pressure water descaling device 7, a 2.0 mm-thick plate is finished by a finishing mill 8.
Then, it was passed through a reducing atmosphere furnace 9 on a hot run table to reduce and remove the oxide scale, and a pinch roll and a lubricant (100% synthetic ester) were applied before winding. The temperature of the steel strip 6 immediately before entering the reducing atmosphere furnace 9 is in the α range or the γ range.
Nitrogen gas 95% atmosphere, furnace passing time is 1.2
Seconds. Temper color oxide scale was not visually observed on the surface of the obtained steel sheet, and when this steel sheet was subjected to deep drawing, a lubricant was applied, so that deep drawing could be performed.
【００２３】（実施例３）熱間圧延ラインにおいて、仕
上圧延終了後の低炭素鋼熱延鋼帯を、本発明法によりイ
ンラインにてスケール除去した。図５に示すように、粗
圧延後の熱延鋼帯６を高圧水デスケーリング装置７によ
りスケール除去した後、仕上圧延機８にて板厚２．０mm
に圧延し、引続きホットランテーブル上にて還元性雰囲
気炉９に通板して酸化スケールを還元除去し、ピンチロ
ールと巻き取り前に潤滑剤（１００％合成エステル）を
塗布した。還元性雰囲気炉９に入る直前の鋼帯６の温度
はα域あるいはγ域であり、還元性雰囲気炉９内は水素
ガス５％窒素ガス９５％の雰囲気とし、炉内の通板時間
は１．２秒間であった。還元性雰囲気炉９を通過後、直
ちに非酸化性雰囲気の冷却ゾーン１０で鋼帯の温度を３
５０℃まで急冷却したので得られた鋼板の表面には肉眼
的には酸化スケールがまったく認められず、深絞り加工
を施したところ、まったく割れが生じなかった。Example 3 In a hot rolling line, a low-carbon steel hot-rolled steel strip after finishing rolling was scale-removed in-line by the method of the present invention. As shown in FIG. 5, after the hot-rolled steel strip 6 after the rough rolling is scale-removed by a high-pressure water descaling device 7, a 2.0 mm-thick plate is finished by a finishing mill 8.
Then, it was passed through a reducing atmosphere furnace 9 on a hot run table to reduce and remove oxide scale, and a pinch roll and a lubricant (100% synthetic ester) were applied before winding. The temperature of the steel strip 6 immediately before entering the reducing atmosphere furnace 9 is in the α range or the γ range, the inside of the reducing atmosphere furnace 9 is an atmosphere of 5% of hydrogen gas and 95% of nitrogen gas, and the passing time in the furnace is 1 2 seconds. Immediately after passing through the reducing atmosphere furnace 9, the temperature of the steel strip is reduced to 3 in the cooling zone 10 in the non-oxidizing atmosphere.
Since the steel sheet was rapidly cooled to 50 ° C., no oxide scale was visually recognized on the surface of the obtained steel sheet, and no deep cracking occurred when deep drawing was performed.
【００２４】（実施例４）熱間圧延ラインにおいて、仕
上圧延終了後の低炭素鋼熱延鋼帯を、本発明法によりイ
ンラインにてスケール除去した。図５に示すように、粗
圧延後の熱延鋼帯６を高圧水デスケーリング装置７によ
りスケール除去した後、仕上圧延機８にて板厚２．０mm
に圧延し、引続きホットランテーブル上にて還元性雰囲
気炉９に通板して酸化スケールを還元除去し、ピンチロ
ールと巻き取り前に潤滑剤（１００％合成エステル）を
塗布した。還元性雰囲気炉９に入る直前の鋼帯６の温度
はα域あるいはγ域であり、還元性雰囲気炉９内は水素
ガス５％窒素ガス９５％の雰囲気とし、炉内の通板時間
は１．２秒間であった。還元性雰囲気炉９を通過後、直
ちに非酸化性雰囲気の冷却ゾーン１０で鋼帯の温度を３
５０℃まで急冷却した後、８５０℃の焼鈍を施した。得
られた鋼板の表面には肉眼的には酸化スケールは認めら
れなかった。また、この鋼板を深絞り加工を施したとこ
ろ、割れの発生も無く良好な加工が行えた。この本発明
例と、還元性雰囲気炉９および冷却ゾーン１０を大気雰
囲気とした比較例について、ＧＤＳ分析により測定した
ＦｅとＯの深さ方向分布を図６および図７に示す。Example 4 In a hot rolling line, a low-carbon steel hot-rolled steel strip after finishing rolling was scale-removed in-line by the method of the present invention. As shown in FIG. 5, after the hot-rolled steel strip 6 after the rough rolling is scale-removed by a high-pressure water descaling device 7, a 2.0 mm-thick plate is finished by a finishing mill 8.
Then, it was passed through a reducing atmosphere furnace 9 on a hot run table to reduce and remove oxide scale, and a pinch roll and a lubricant (100% synthetic ester) were applied before winding. The temperature of the steel strip 6 immediately before entering the reducing atmosphere furnace 9 is in the α range or the γ range, the inside of the reducing atmosphere furnace 9 is an atmosphere of 5% hydrogen gas and 95% nitrogen gas, and the passing time in the furnace is 1 hour. 2 seconds. Immediately after passing through the reducing atmosphere furnace 9, the temperature of the steel strip is reduced to 3 in the cooling zone 10 in a non-oxidizing atmosphere.
After rapidly cooling to 50 ° C., annealing at 850 ° C. was performed. No oxide scale was visually observed on the surface of the obtained steel sheet. Further, when the steel sheet was subjected to deep drawing, good processing was performed without occurrence of cracks. FIGS. 6 and 7 show the distributions of Fe and O in the depth direction measured by GDS analysis with respect to this example of the present invention and a comparative example in which the reducing atmosphere furnace 9 and the cooling zone 10 were set to the air atmosphere.
【００２５】図７の比較例には、従来の熱延鋼板と同様
の酸化スケールが認められた。これに対して図６の本発
明例は、図７の比較例と比べて明らかなように、表面の
酸化スケールが還元されていることがわかる。すなわ
ち、本発明によれば圧延材表面にスケールが無い熱延鋼
板を製造することができ、なおかつ深絞りなどの２次加
工においても潤滑剤の塗布が不要になる。In the comparative example shown in FIG. 7, the same oxide scale as that of the conventional hot-rolled steel sheet was observed. On the other hand, in the example of the present invention in FIG. 6, the oxide scale on the surface is reduced as is apparent from comparison with the comparative example in FIG. That is, according to the present invention, a hot-rolled steel sheet having no scale on the surface of a rolled material can be manufactured, and the application of a lubricant is not required even in secondary processing such as deep drawing.
【００２６】[0026]
【発明の効果】本発明方法は、鋼板の熱間圧延ラインに
おいて、最終圧延後の通板中の鋼板を水素ガス含有雰囲
気にさらずことで、圧延終了後に存在する表面酸化スケ
ールを還元し、インラインにて酸洗処理を行わずに除去
することができる。このため、従来のような酸洗ライン
が不要となり、工程省略のほか、環境問題などにより今
後ますます厳しくなる廃酸処理が不要になる。また、イ
ンラインで潤滑を施すことにより鋼板に潤滑性を持たす
ことができ、その後の二次加工での潤滑剤の塗布が不要
になる。According to the method of the present invention, in a hot rolling line for a steel sheet, by reducing the steel sheet in the thread after the final rolling to a hydrogen gas-containing atmosphere, the surface oxide scale existing after the rolling is reduced, It can be removed in-line without performing pickling. For this reason, a conventional pickling line is not required, and in addition to omitting a process, a waste acid treatment which becomes more severe in the future due to environmental problems and the like becomes unnecessary. In addition, lubrication can be imparted to the steel sheet by performing in-line lubrication, and it is not necessary to apply a lubricant in the subsequent secondary processing.
【図１】本発明法における酸化スケールの還元温度と還
元所要時間との関係例を示すグラフである。FIG. 1 is a graph showing an example of the relationship between the reduction temperature of an oxide scale and the time required for reduction in the method of the present invention.
【図２】本発明法における雰囲気中の水素濃度と酸化ス
ケールの還元所要時間との関係例を示すグラフである。FIG. 2 is a graph showing an example of the relationship between the hydrogen concentration in the atmosphere and the time required for reducing the oxide scale in the method of the present invention.
【図３】（ａ）、（ｂ）、（ｃ）は、従来の酸化スケー
ルの還元過程を示す説明図である。FIGS. 3 (a), (b) and (c) are explanatory views showing a conventional reduction process of an oxidized scale.
【図４】（ａ）、（ｂ）、（ｃ）は、本発明法における
酸化スケールの還元過程を示す説明図である。FIGS. 4 (a), (b), and (c) are explanatory views showing a reduction process of an oxide scale in the method of the present invention.
【図５】本発明法における実施例の設備概要を示す説明
図である。FIG. 5 is an explanatory diagram showing an outline of equipment of an embodiment in the method of the present invention.
【図６】本発明例で得られた鋼板について、Ｆｅおよび
Ｏの表面からの深さ方向濃度分布を示すグラフである。FIG. 6 is a graph showing the concentration distribution of Fe and O in the depth direction from the surface of the steel sheet obtained in the example of the present invention.
【図７】比較例で得られた鋼板について、ＦｅおよびＯ
の表面からの深さ方向濃度分布を示すグラフである。FIG. 7 shows Fe and O of the steel sheet obtained in the comparative example.
5 is a graph showing a concentration distribution in the depth direction from the surface of FIG.
１ 地鉄 ２ スケール層 ３ 還元鉄層 ４ クラック ５ 還元鉄 ６ 熱延鋼帯 ７ 高圧水デスケーリング装置 ８ 仕上圧延機 ９ 還元性雰囲気炉 １０ 冷却炉および／または焼鈍炉 １１ ピンチロール １２ 巻取機 １３ 潤滑ノズル DESCRIPTION OF SYMBOLS 1 Ground iron 2 Scale layer 3 Reduced iron layer 4 Crack 5 Reduced iron 6 Hot rolled steel strip 7 High pressure water descaling device 8 Finishing rolling mill 9 Reducing atmosphere furnace 10 Cooling furnace and / or annealing furnace 11 Pinch roll 12 Winding machine 13 Lubrication nozzle
───────────────────────────────────────────────────── フロントページの続き (72)発明者 近藤 泰光 千葉県富津市新富20−１ 新日本製鐵株式 会社技術開発本部内 Ｆターム(参考） 4E002 AD04 BC08 BD05 BD10 CB03 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Yasumitsu Kondo 20-1 Shintomi, Futtsu-shi, Chiba F-term in the Technology Development Division of Nippon Steel Corporation (reference) 4E002 AD04 BC08 BD05 BD10 CB03
Claims (6)
行圧延材の尾端部と後行圧延材の先端部を接合し鋼板を
熱間圧延するラインにおいて、最終仕上げ圧延機とピン
チロール間で還元性雰囲気を通板させることにより、鋼
板表面の酸化スケールを還元除去することを特徴とする
熱延鋼板の製造方法。1. A final finishing mill and a pinch roll in a line for joining a tail end of a preceding rolling material and a leading end of a succeeding rolling material between a rough rolling facility and a finishing rolling facility and hot rolling a steel sheet. A method for producing a hot-rolled steel sheet, comprising reducing and removing oxide scale on the surface of a steel sheet by passing a reducing atmosphere between the steel sheets.
部が不活性ガスあるいはＮ2 ガスからなることを特徴と
する請求項１記載の熱延鋼板の製造方法。2. The method for producing a hot-rolled steel sheet according to claim 1, wherein the composition of the reducing atmosphere is 5% or more of hydrogen and the balance is made of an inert gas or N 2 gas.
雰囲気中で冷却および／または焼鈍することを特徴とす
る請求項１または請求項２記載の熱延鋼板の製造方法。3. The method for producing a hot-rolled steel sheet according to claim 1, wherein after the sheet is passed through a reducing atmosphere, the sheet is cooled and / or annealed in a non-oxidizing atmosphere.
るいはＮ2 ガス１００％とすることを特徴とする請求項
３記載の熱延鋼板の製造方法。4. The method for producing a hot-rolled steel sheet according to claim 3, wherein the composition of the non-oxidizing atmosphere is an inert gas or 100% N 2 gas.
化性雰囲気を通板した後、ピンチロールと巻き取り前に
塑性加工用として用いられる所定の潤滑剤を塗布するこ
とにより自己潤滑性をもった鋼板とすることを特徴とす
る請求項１〜４のいずれか１項記載の熱延鋼板の製造方
法。5. After passing through a reducing atmosphere or a reducing atmosphere and a non-oxidizing atmosphere, a predetermined lubricant used for plastic working is applied before being wound with a pinch roll and self-lubricating. The method for producing a hot-rolled steel sheet according to any one of claims 1 to 4, wherein the hot-rolled steel sheet is used.
方法によって得られた熱延鋼板を深絞り加工を施してな
ることを特徴とする缶製品。6. A can product obtained by subjecting a hot-rolled steel sheet obtained by the method according to any one of claims 1 to 5 to deep drawing.
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|---|---|---|---|
| JP2000103335A JP4299435B2 (en) | 2000-04-05 | 2000-04-05 | Manufacturing method of hot-rolled steel sheet |
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| US8784577B2 (en) | 2009-01-30 | 2014-07-22 | Jfe Steel Corporation | Thick high-tensile-strength hot-rolled steel sheet having excellent low-temperature toughness and manufacturing method thereof |
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| US9809869B2 (en) | 2009-01-30 | 2017-11-07 | Jfe Steel Corporation | Thick-walled high-strength hot rolled steel sheet having excellent hydrogen induced cracking resistance and manufacturing method thereof |
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