JPH0994601A - Production of hot rolled steel sheet containing copper having good surface condition - Google Patents
Production of hot rolled steel sheet containing copper having good surface conditionInfo
- Publication number
- JPH0994601A JPH0994601A JP1109196A JP1109196A JPH0994601A JP H0994601 A JPH0994601 A JP H0994601A JP 1109196 A JP1109196 A JP 1109196A JP 1109196 A JP1109196 A JP 1109196A JP H0994601 A JPH0994601 A JP H0994601A
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- JP
- Japan
- Prior art keywords
- slab
- less
- width direction
- processing
- rolling
- 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.)
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Links
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- Metal Rolling (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、主として一般建
材、コンテナ用素材、自動車の足廻り部品用素材等に用
いられる耐食性に優れた含銅熱延鋼板の製造方法に関す
るものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a hot-rolled copper-containing steel sheet having excellent corrosion resistance, which is mainly used for general building materials, materials for containers, materials for undercarriage parts of automobiles, and the like.
【０００２】[0002]
【従来の技術】一般に常温での耐食性を向上させるため
にはCuを0.2 ％以上添加することが有効とされている。
しかし、含銅鋼の欠点として熱間脆性があり、高温で加
工する際に鋼板に割れが発生し製品の表面疵の原因とな
ることが知られている。この熱間加工時の割れの原因は
概ね次のように考えられている。2. Description of the Related Art Generally, it is considered effective to add Cu by 0.2% or more in order to improve the corrosion resistance at room temperature.
However, it is known that a drawback of copper-containing steel is hot brittleness, which causes cracks in the steel sheet during processing at high temperatures, which causes surface defects of the product. The causes of cracking during hot working are generally considered as follows.
【０００３】すなわち、加熱炉においてスラブを加熱し
た際、Feがスケールとして酸化するためFeより酸化しに
くいCuはFeとスケールの界面に富化層を形成する。この
富化層のCu濃度が約８％以上に達した場合、1094℃以上
で液相を生じる。この液相の生じた脆弱な鋼板表面が熱
間加工を受けた場合に割れの発生に至るというものであ
る。That is, when the slab is heated in a heating furnace, Fe oxidizes as a scale and Cu, which is less oxidizable than Fe, forms an enriched layer at the interface between Fe and scale. When the Cu concentration in this enriched layer reaches about 8% or more, a liquid phase is generated at 1094 ° C or more. When the brittle steel plate surface in which the liquid phase is generated is subjected to hot working, cracking occurs.
【０００４】この表面割れ発生機構をもとに、割れすな
わち製品の表面疵を発生させないような工夫が種々行わ
れてきた。最も簡単な方法としてはNiをCuの1/2 以上の
量だけ添加し、Cu富化層の融点を上げる方法が知られて
いる。しかし、この方法は高価なNiを多量に必要とする
ため著しいコスト上昇につながる。また、Siについても
Cuの富化層がスケール側にくることにより表面疵を改善
する効果があるといわれている。On the basis of this surface crack generation mechanism, various measures have been taken to prevent cracks, that is, surface defects of products. The simplest method is to add Ni in an amount of 1/2 or more of Cu to raise the melting point of the Cu-rich layer. However, this method requires a large amount of expensive Ni, which leads to a significant cost increase. Also for Si
It is said that the Cu-enriched layer has the effect of improving the surface defects by coming to the scale side.
【０００５】Ni添加量低減方法としては特開平６−3130
2 号公報、同６−297025号公報にNi酸化物、Si酸化物を
スラブ表面に塗布する方法が開示されている。これはNi
およびSiの効果をスラブ表面のみとすることを目的とし
ているが、Ni、Si酸化物の塗布方法が不明確であり、ま
た、塗布するための新たな設備を設ける必要がある。A method for reducing the amount of Ni added is disclosed in Japanese Patent Laid-Open No. 6-3130.
No. 2 and No. 6-297025 disclose methods of applying Ni oxide and Si oxide to the slab surface. This is Ni
The purpose is to make the effect of Si and Si only on the slab surface, but the coating method of Ni and Si oxides is unclear, and new equipment for coating must be provided.
【０００６】Ni添加以外の方法としては、特開昭49−12
3458号公報に加熱温度を1300℃以上とし、1090℃以上で
粗圧延を完了し、引き続き1050℃以下まで冷却したのち
仕上げ圧延を行う方法が開示されている。これはCuをス
ケール中に拡散させること、およびCuの脆化が最も激し
い1050〜1100℃での熱間加工を避けることにより表面疵
抑制を狙ったものである。しかし、加熱温度を1300℃以
上とすることは炉の損傷やエネルギーコストの著しい上
昇などが伴い、量産ラインで実施することは困難であ
る。As a method other than the addition of Ni, Japanese Patent Laid-Open No. 49-12
Japanese Patent No. 3458 discloses a method in which a heating temperature is set to 1300 ° C. or higher, rough rolling is completed at 1090 ° C. or higher, followed by cooling to 1050 ° C. or lower and then finish rolling. This aims to suppress surface defects by diffusing Cu into the scale and avoiding hot working at 1050-1100 ° C, where Cu is most brittle. However, if the heating temperature is set to 1300 ° C or higher, it is difficult to carry out in a mass production line because of damage to the furnace and a significant increase in energy cost.
【０００７】また、加熱温度1300℃以下における表面疵
の防止方法として、特開昭51−126322号公報にスラブ表
面を熱間溶削したのち直ちに熱間圧延を実施する、また
は、熱間溶削したのち加熱時間、加熱温度を厳しく制限
し熱間圧延を実施する方法が開示されている。これらは
Cuが富化層を形成する前に熱間加工を完了させてしまう
というものであるが、そのためには新たに設備を設ける
必要があり、また加熱条件を著しく制約するという欠点
がある。Further, as a method for preventing surface defects at a heating temperature of 1300 ° C. or lower, JP-A-51-126322 discloses hot shaving the slab surface and then hot rolling, or hot shaving. After that, a method is disclosed in which the heating time and the heating temperature are strictly limited to carry out hot rolling. They are
Although the hot working is completed before the Cu-rich layer is formed, it has the drawback that new equipment must be installed for that purpose and the heating conditions are significantly restricted.
【０００８】[0008]
【発明が解決しようとする課題】従来技術は含銅鋼の表
面疵防止のために有効ではあるが、制限が多く実際の操
業においては実現困難である。ここに本発明の目的は、
実際の操業に容易に実施でき、かつ表面疵の発生を効果
的に防止できる含銅熱延鋼板の製造方法を提供すること
である。Although the prior art is effective for preventing surface flaws in copper-containing steel, it is difficult to realize it in actual operation due to many limitations. Here, the object of the present invention is to
It is an object of the present invention to provide a method for producing a copper-containing hot-rolled steel sheet which can be easily carried out in actual operation and which can effectively prevent the occurrence of surface defects.
【０００９】[0009]
【課題を解決するための手段】そこで本発明者らは、熱
延鋼板に対象を絞って表面疵の抑制方法を研究した結
果、熱延鋼板での含銅鋼の表面疵防止方法を開発した。
すなわち、熱延鋼板の特徴として、熱間圧延ではロール
接触表面が大きいこと、製品厚が薄いため製品端面の劣
化は問題とならないこと、そして加熱後に幅調整あるい
はスケール剥離向上の目的で幅方向の加工が加わること
が挙げられることに着目し、熱延鋼板の表面疵防止方法
として幅方向加工時の温度を制御することで、また幅方
向加工時の加工速度を制御することで、若干端面の劣化
はみられるものの、効果的に表面疵の発生防止が図ら
れ、量産ラインで適用が容易な製造方法が実現できるこ
とを知り、本発明を完成した。本発明に係わる表面性状
の良好な含銅熱延鋼板の製造方法は次の通りである。Therefore, as a result of researching a method for suppressing surface flaws by focusing on hot rolled steel sheets, the present inventors have developed a method for preventing surface flaws of copper-containing steel in hot rolled steel sheets. .
That is, the characteristics of hot-rolled steel sheet are that the roll contact surface is large in hot rolling, that the deterioration of the end surface of the product is not a problem because the product thickness is thin, and the width direction is adjusted after heating for the purpose of width adjustment or scale peeling improvement. Focusing on the fact that processing is added, by controlling the temperature during width direction processing as a method for preventing surface defects of hot rolled steel sheets, and by controlling the processing speed during width direction processing The present invention has been completed based on the knowledge that a surface flaw can be effectively prevented from occurring although deterioration is observed, and a manufacturing method that can be easily applied to a mass production line can be realized. The method for producing a copper-containing hot-rolled steel sheet having good surface properties according to the present invention is as follows.
【００１０】(1) 重量％で、Ｃ: 0.20％以下、 Mn：0.
10〜1.50％、Ｓ: 0.020 ％以下、Cu：0.20〜0.50％、残
部をFeおよび不可避的不純物から成る鋼組成を有する素
材鋼スラブを加熱したのち、スラブ幅方向の加工をスラ
ブ幅の４％以上行う場合、その加工を1170℃以上で実施
し、Ar3 点以上で仕上げ圧延を完了することを特徴とす
る表面性状の良好な含銅熱延鋼板の製造方法。(1) C: 0.20% or less, Mn: 0.
10 to 1.50%, S: 0.020% or less, Cu: 0.20 to 0.50%, the balance is a steel slab having a steel composition consisting of Fe and unavoidable impurities. After heating, the slab width is processed to 4% of the slab width. In the case of performing the above, the process is carried out at 1170 ° C. or higher, and finish rolling is completed at 3 or more points of Ar.
【００１１】(2) 重量％で、Ｃ: 0.20％以下、 Mn：0.
10〜1.50％、Ｓ: 0.020 ％以下、Cu：0.20〜0.50％ 残部をFeおよび不可避的不純物から成る鋼組成を有する
素材鋼スラブを加熱したのち、スラブ幅方向の加工をス
ラブ幅の４％以上行う場合、その加工を幅方向の下記
(1) 式で定義される加工速度(*1) 250mm/sec以下で実施
し、Ar3 点以上で仕上げ圧延を完了することを特徴とす
る表面性状の良好な含銅熱延鋼板の製造方法。(2) In% by weight, C: 0.20% or less, Mn: 0.
10 to 1.50%, S: 0.020% or less, Cu: 0.20 to 0.50% After heating the base steel slab having a steel composition composed of Fe and inevitable impurities, the balance is processed in the slab width direction at 4% or more of the slab width. If you do the following, in the width direction
Processing speed defined by formula (1) (* 1) Manufacturing method for copper-containing hot-rolled steel sheet with good surface properties, which is performed at 250 mm / sec or less and finish rolling is completed at Ar 3 points or more .
【００１２】 加工速度(*1)＝ (元スラブ幅−加工後スラブ幅) ／幅方向加工時間 ・・・・・(1) (3) 前記鋼組成が、さらに、重量％で、Si:1.2％以下、
Ti:0.15 ％以下、Nb:0.05 ％以下の少なくとも１種、お
よび／またはＰ:0.15 ％以下、Cr:1.5％以下の少なくと
も１種以上を含有する上記(1) または(2) 記載の表面性
状の良好な含銅熱延鋼板の製造方法。Machining speed (* 1) = (original slab width-post-machining slab width) / width direction machining time (1) (3) The steel composition further contains Si: 1.2% by weight. %Less than,
The surface texture according to (1) or (2) above, which contains at least one of Ti: 0.15% or less, Nb: 0.05% or less, and / or P: 0.15% or less, Cr: 1.5% or less. For manufacturing a copper-containing hot-rolled steel sheet of good quality.
【００１３】[0013]
【発明の実施の形態】すなわち、本発明によれば、Cu:
0.50 ％以下では、幅方向の加工がスラブ幅の４％未満
の場合、ロール接触面では疵の発生は見られず、鋼板端
面がわずかに劣化するのみであることがわかった。ま
た、幅方向にスラブ幅の４％以上の加工を加えた場合
は、鋼板表面に疵の発生が見られる場合もあるが、加工
温度を1170℃以上とするとき、またはスラブ幅方向の加
工速度が250mm/sec 以下のときは疵の発生が抑えられる
ことを見い出した。しかし、Cu:0.50 ％を超えると加工
温度が1170℃以上であっても、また幅方向の加工速度が
250mm/sec 以下でも表面疵が発生する場合がある。つま
りCu:0.50 ％以下、加工温度が1170℃以上、または幅方
向加工速度250mm/sec 以下では非ロール接触面 (自由
端) のみ疵が発生する。BEST MODE FOR CARRYING OUT THE INVENTION That is, according to the present invention, Cu:
At 0.50% or less, it was found that when the widthwise processing was less than 4% of the slab width, no flaw was observed on the roll contact surface and the steel plate end surface was only slightly deteriorated. When 4% or more of the slab width is applied in the width direction, flaws may appear on the steel plate surface, but when the processing temperature is 1170 ° C or higher, or the processing speed in the slab width direction. It was found that when the value is less than 250 mm / sec, the occurrence of flaws can be suppressed. However, if Cu: 0.50% is exceeded, the processing speed in the width direction will be increased even if the processing temperature is 1170 ° C or higher.
Surface defects may occur even at 250 mm / sec or less. That is, when Cu: 0.50% or less, the processing temperature is 1170 ° C or more, or the width direction processing speed is 250 mm / sec or less, only the non-roll contact surface (free end) is flawed.
【００１４】次に、本発明の製造方法において鋼組成お
よび加工条件を上記のように定めた理由について以下に
詳細に説明する。まず、本発明の対象となる素材鋼スラ
ブの化学組成を定めた理由を作用効果とともに述べる。
本明細書において「％」は特にことわりがなり限り、重
量％を表す。Next, the reason why the steel composition and working conditions are set as above in the manufacturing method of the present invention will be described in detail below. First, the reason for defining the chemical composition of the raw material steel slab which is the subject of the present invention will be described together with the action and effect.
In the present specification, “%” represents% by weight unless otherwise specified.
【００１５】Ｃ: 0.20％以下 Ｃは機械特性に対して影響の大きい元素である。Ｃが0.
20％を超えると加工性が著しく劣化し、冷間でのプレス
加工において所定の形状を得られない場合がある。ま
た、構造物とした場合、溶接部近傍の軟化、硬化が発生
し強度、靱性が十分得られない場合がある。そのためＣ
の含有量は0.20％以下とした。好ましくは0.03〜0.15％
である。C: 0.20% or less C is an element having a great influence on mechanical properties. C is 0.
If it exceeds 20%, the workability is remarkably deteriorated, and a predetermined shape may not be obtained in cold press working. Further, in the case of a structure, softening and hardening may occur in the vicinity of the welded portion, so that sufficient strength and toughness may not be obtained. Therefore C
Content was 0.20% or less. Preferably 0.03-0.15%
It is.
【００１６】Mn：0.10〜1.50％ MnはMnＳとしてＳの熱間脆化 (約900 〜1000℃) を防止
し表面疵の発生を防ぐ働きがある。このため下限を0.10
％とした。またMnは強化元素として有効であるが多量に
添加すると伸びが低下し加工性が著しく劣化する。その
ためMnの上限を1.50％とした。好ましくは0.30〜1.30％
である。Mn: 0.10 to 1.50% Mn acts as MnS to prevent hot embrittlement of S (about 900 to 1000 ° C.) and prevent surface defects from occurring. Therefore, the lower limit is 0.10
%. Mn is effective as a strengthening element, but if it is added in a large amount, elongation is reduced and workability is significantly deteriorated. Therefore, the upper limit of Mn is set to 1.50%. Preferably 0.30 to 1.30%
It is.
【００１７】Ｓ: 0.020 ％以下 Ｓは熱間加工性を劣化させる元素であり、できるだけ少
ないことが望ましい。しかし、Ｓが0.020 ％以下ではそ
の劣化が小さいことから上限を0.020 ％とした。好まし
くは、0.010 ％以下である。S: 0.020% or less S is an element that deteriorates hot workability, and it is desirable that S is as small as possible. However, if S is 0.020% or less, the deterioration is small, so the upper limit was made 0.020%. Preferably, it is not more than 0.010%.
【００１８】Cu：0.20〜0.50％ Cuは耐食性に対して重要な元素である。耐食性向上のた
めには0.20％以上の添加が必要であるため下限を0.20％
とした。また、耐食性に関しては0.70％程度まで上昇は
見られるが、Cuを0.50％を超えて添加すると、本発明の
方法では表面疵を皆無にすることは困難である。そのた
め上限は0.50％とした。好ましくは、0.30〜0.50％であ
る。Cu: 0.20 to 0.50% Cu is an important element for corrosion resistance. To improve corrosion resistance, 0.20% or more must be added, so the lower limit is 0.20%.
And Further, although the corrosion resistance can be increased to about 0.70%, if Cu is added in an amount of more than 0.50%, it is difficult to eliminate surface defects by the method of the present invention. Therefore, the upper limit was made 0.50%. Preferably, it is 0.30 to 0.50%.
【００１９】Si、Ti、Nb、Ｐ、Cr：これらは必要に応じ
て添加してもよい。Si、Ti、Nb、Ｐ、Crを添加するのは
次の効果を期待する場合である。Si, Ti, Nb, P, Cr: These may be added if necessary. The addition of Si, Ti, Nb, P and Cr is a case where the following effects are expected.
【００２０】Si: 1.2 ％以下 Siは成形性の劣化が少なく鋼板の強度を向上させるのに
適した元素である。このため自動車の足廻り部品などに
含銅熱延鋼板を使用する場合などはSiを添加するのは有
効な手段である。しかし1.2 ％を超えて添加するとFe2S
iO4 が大量に発生し異常酸化の原因となりスケールロス
が大きくなる。そのため上限は1.2 ％とした。好ましく
は、0.50〜1.10％である。Si: 1.2% or less Si is an element suitable for improving the strength of a steel sheet with little deterioration in formability. For this reason, adding Si is an effective means when using copper-containing hot-rolled steel sheets for undercarriage parts of automobiles. However, when added in excess of 1.2%, Fe 2 S
A large amount of iO 4 is generated, causing abnormal oxidation and increasing scale loss. Therefore, the upper limit was 1.2%. It is preferably 0.50 to 1.10%.
【００２１】Ti：0.15％以下、Nb：0.05％以下 Ti、NbはそれぞれTiＣ、NbＣとして析出して強度上昇に
有効な元素である。しかし、Tiは0.15％を超えて添加し
てもその効果は小さくなり、コスト上昇につながるのみ
のため上限を0.15％とした。同様な理由によりNbも上限
を0.05％とした。好ましくは、Ti：0.02〜0.12％、Nb：
0.01〜0.035 ％である。Ti: 0.15% or less, Nb: 0.05% or less Ti and Nb are elements effective in increasing strength by precipitating as TiC and NbC, respectively. However, even if Ti is added in excess of 0.15%, its effect will be small and only increase in cost, so the upper limit was made 0.15%. For the same reason, the upper limit of Nb was set to 0.05%. Preferably, Ti: 0.02 to 0.12%, Nb:
It is 0.01 to 0.035%.
【００２２】Ｐ: 0.15％以下 Ｐは耐食性に対して有効な元素である。そのためさらな
る耐食性の向上が必要な場合は添加すると良い。しか
し、Ｐは0.15％を超えて添加しても耐食性の向上は見ら
れないだけでなく鋼の靱性を劣化させるため上限は0.15
％とした。好ましくは、0.05〜0.12％である。P: 0.15% or less P is an element effective for corrosion resistance. Therefore, if it is necessary to further improve the corrosion resistance, it may be added. However, if P is added in excess of 0.15%, not only the corrosion resistance is not improved but also the toughness of the steel is deteriorated, so the upper limit is 0.15%.
%. Preferably, it is 0.05 to 0.12%.
【００２３】Cr: 1.5 ％以下 Crも耐食性に有効な元素であり、特に耐海水腐食性が有
効である。このため耐海水腐食性が必要な場合は添加す
る必要がある。しかし1.5 ％を超えてもその効果は飽和
するため上限を1.5 ％とした。好ましくは、1.0 〜1.5
％である。Cr: 1.5% or less Cr is also an element effective in corrosion resistance, and particularly effective in seawater corrosion resistance. Therefore, if seawater corrosion resistance is required, it must be added. However, the effect is saturated even if it exceeds 1.5%, so the upper limit was made 1.5%. Preferably 1.0-1.5
%.
【００２４】次に製造条件の限定理由について説明す
る。熱間圧延は、スラブを加熱炉より抽出後、スラブ幅
方向加工→デスケーリング→粗圧延→仕上げ圧延→冷却
→巻き取りの各工程を経て行われる。Next, the reasons for limiting the manufacturing conditions will be described. The hot rolling is performed after each step of extracting the slab from the heating furnace and then processing the slab in the width direction → descaling → rough rolling → finish rolling → cooling → winding.
【００２５】スラブ幅方向加工量：スラブ幅の４％以上 スラブ幅方向の加工量がスラブ幅の圧下量で４％未満と
小さい場合は、スラブは幅方向の加工を加えても表面疵
は発生しにくい。このため、スラブ幅方向の加工量がス
ラブ幅の４％未満は本発明の範囲外となる。このためス
ラブ幅方向の加工量はスラブ幅の圧下量で４％以上とし
た。好ましくは６％以上である。Slab width direction working amount: 4% or more of the slab width If the working amount in the slab width direction is less than 4% of the reduction amount of the slab width, the slab has surface flaws even if it is processed in the width direction. Hard to do. Therefore, if the amount of processing in the slab width direction is less than 4% of the slab width, it is outside the scope of the present invention. Therefore, the processing amount in the slab width direction is set to 4% or more in terms of the reduction amount of the slab width. It is preferably at least 6%.
【００２６】スラブ幅方向加工の加工温度：1170℃以上 スラブ幅方向加工の加工温度を1170℃以上とすることは
表面疵防止の上で重要である。含銅熱延鋼板の表面疵発
生原因は幅方向の加工に起因するところが大きい。すな
わち幅方向の加工では鋼板表面は自由端となり製品時に
表面側に疵が発生する原因となるためである。この幅方
向の加工をCuの脆化温度以外で行うことにより含銅熱延
鋼板の表面疵は防止可能である。このためスラブ幅方向
加工の加工温度を1170℃以上とした。好ましくは、1200
〜1250℃である。Slab width direction processing temperature: 1170 ° C. or higher It is important to prevent the surface flaws by setting the slab width direction processing temperature to 1170 ° C. or higher. The cause of surface defects of the copper-containing hot-rolled steel sheet is largely due to the processing in the width direction. That is, in the width direction processing, the surface of the steel sheet becomes a free end, which may cause flaws on the surface side during product processing. Surface flaws of the copper-containing hot-rolled steel sheet can be prevented by performing the widthwise working at a temperature other than the brittleness temperature of Cu. Therefore, the processing temperature of the slab width direction processing was set to 1170 ° C or higher. Preferably 1200
~ 1250 ℃.
【００２７】スラブ幅方向加工の加工速度：250mm/sec
以下 本発明は、その別の面からは、幅方向の加工速度を規制
することによって、加工時の表面疵防止を図るのであ
る。Processing speed of slab width direction processing: 250 mm / sec
From the other aspect, the present invention aims to prevent surface flaws during processing by limiting the processing speed in the width direction.
【００２８】スラブ幅方向加工の加工速度を250 mm/sec
以下とすることは表面疵防止の上で重要である。含銅熱
延鋼板の表面疵発生原因は幅方向の加工に起因するとこ
ろが大きい。すなわち幅方向の加工では鋼板表面は自由
端となり製品時に表面側に疵が発生する原因となるため
である。鋼板表面疵と幅方向の加工速度について検討し
た結果、加工速度が大きくなるに従い表面疵が発生する
確立が高くなることがわかった。従って、幅方向の加工
速度の上限を規定することによりCuに起因した表面の脆
化は防止可能である。このためスラブ幅方向加工の加工
速度の上限を250mm/sec 以下とした。好ましくは、200m
m/sec 以下である。ここでスラブ幅方向加工速度とは、
前述の(1) 式で示されるように、 (元スラブ幅−加工後
スラブ幅) ／幅方向加工時間と定義する。The processing speed of the slab width direction processing is 250 mm / sec.
The following is important for preventing surface defects. The cause of surface defects of the copper-containing hot-rolled steel sheet is largely due to the processing in the width direction. That is, in the width direction processing, the surface of the steel sheet becomes a free end, which may cause flaws on the surface side during product processing. As a result of studying the surface flaws on the steel sheet and the machining speed in the width direction, it was found that the probability of surface flaws increasing as the machining speed increased. Therefore, by specifying the upper limit of the processing speed in the width direction, the embrittlement of the surface due to Cu can be prevented. Therefore, the upper limit of the processing speed for slab width direction processing was set to 250 mm / sec or less. Preferably 200m
It is less than m / sec. Here, the slab width direction processing speed is
As shown in the above equation (1), it is defined as (original slab width-post-machining slab width) / width direction machining time.
【００２９】仕上げ圧延温度：Ar3 点以上 Ar3 点以上で仕上げ圧延を完了させる理由は、圧延中に
変態が起きると圧延荷重の変化により鋼板の平坦度や寸
法精度が大きく劣化するばかりでなく、通板そのものが
困難となるためである。Finishing rolling temperature: Ar 3 points or more Ar 3 points or more is the reason for completing the finishing rolling. Not only the flatness and dimensional accuracy of the steel sheet are greatly deteriorated due to changes in rolling load when transformation occurs during rolling, but also The reason is that it becomes difficult for the threading itself.
【００３０】巻取り温度については、含銅熱延鋼板の表
面に与える影響はないが、巻き取り不良の防止のため70
0 ℃以下とすることが望ましい。次に、本発明の作用効
果を実施例に基づいてさらに具体的に説明する。The winding temperature has no influence on the surface of the copper-containing hot-rolled steel sheet, but is 70% to prevent winding defects.
It is desirable that the temperature is 0 ° C. or less. Next, the function and effect of the present invention will be described more specifically based on Examples.
【００３１】[0031]
(実施例１)本例では、Ｃ＝0.10％、Mn＝0.50％、Ｓ＝0.
015 ％の基本鋼組成に、Cu＝0.2、0.5 、0.8 ％をそれ
ぞれ添加した３種の鋼組成を持った素材鋼スラブ240t×
1200ｗ×6000〜7000L (mm)を作製し、加熱炉にて加熱、
抽出後、スラブ幅方向加工→デスケーリング→粗圧延→
仕上げ圧延→冷却→巻き取りの順で熱間圧延を実施し
た。(Example 1) In this example, C = 0.10%, Mn = 0.50%, S = 0.
Raw steel slab with 3 kinds of steel composition of Cu = 0.2, 0.5, 0.8% added to 015% basic steel composition 240t ×
1200w × 6000〜7000L (mm) is produced and heated in a heating furnace.
After extraction, slab width direction processing → descaling → rough rolling →
Hot rolling was performed in the order of finish rolling, cooling, and winding.
【００３２】スラブ幅方向の加工はサイジングプレスで
スラブ幅の約12.5％(150 mm)実施した。また、スラブ加
熱温度は全て約1220℃とし、その後ホットランテーブル
上で所定の幅方向加工温度まで冷却を実施した。圧延は
幅方向加工後に粗圧延、タンデムの仕上げ圧延により板
厚2.6 mmにまで実施した。Processing in the slab width direction was performed by a sizing press at about 12.5% (150 mm) of the slab width. The slab heating temperature was set to about 1220 ° C., and then the slab was cooled to a predetermined width-direction processing temperature on a hot run table. After rolling in the width direction, rough rolling and tandem finish rolling were performed to a plate thickness of 2.6 mm.
【００３３】図１はこのときの加工温度と表面疵発生率
(%) との関係を表わすグラフである。図１のように、幅
方向加工温度は約1100℃の時に最も表面疵が発生してい
るのが判る。さらにCu:0.50 ％以下では幅方向加工温度
が1170℃以上で表面疵の発生が抑えられている。逆にCu
＝0.8 ％では幅方向の加工温度が1170℃以上でも表面疵
は、わずかではあるが、発生する場合がある。FIG. 1 shows the processing temperature and the occurrence rate of surface defects at this time.
It is a graph showing the relationship with (%). As shown in FIG. 1, it can be seen that the surface defects are most generated when the processing temperature in the width direction is about 1100 ° C. Further, when Cu: 0.50% or less, the surface flaw generation is suppressed when the width-direction processing temperature is 1170 ° C or higher. Conversely Cu
= 0.8%, surface defects may occur at a processing temperature in the width direction of 1170 ° C or higher, albeit slightly.
【００３４】(実施例２)表１の含有成分の鋼(Ar3≒800
℃) を常法により溶製後、幅方向加工温度、加工量を変
化させて熱間圧延を行った。製造したスラブの寸法は24
0t×1200ｗ×6000〜7000L(mm) とし、実施例１の場合と
同様に抽出後、サイジングプレスにより幅方向圧下率２
％(24mm)〜20％(240mm) のスラブ幅方向加工を実施した
後、粗圧延、仕上げ圧延、コイル巻取りを実施した。(Example 2) Steel containing the components shown in Table 1 (Ar 3 ≈ 800)
(° C) was melted by a conventional method, and then hot rolling was performed while changing the width direction working temperature and the working amount. The size of the manufactured slab is 24
0t × 1200w × 6000 to 7000L (mm), after extraction as in the case of Example 1, a width direction rolling reduction of 2 by a sizing press.
% (24 mm) to 20% (240 mm) slab width direction processing was performed, and then rough rolling, finish rolling, and coil winding were performed.
【００３５】その結果を表２に示す。表面疵発生の有無
は、次工程である酸洗ラインにて目視による検査を行っ
た結果である。この結果より本発明の方法では含銅熱延
鋼板の表面に疵が発生しないことが判る。The results are shown in Table 2. The presence or absence of surface flaws is the result of visual inspection in the next step, the pickling line. From this result, it can be seen that the method of the present invention does not cause flaws on the surface of the copper-containing hot-rolled steel sheet.
【００３６】また機械特性は酸洗ラインにて熱延コイル
の1/4wの位置より採取したサンプルをJIS ５号試験片に
て圧延方向の引張試験を行った結果である。本発明方法
により得られた鋼は良好な機械特性を有しているのに対
して、Ｃ、Mnを過剰に添加したものは、伸びの劣化が著
しいことが判る。さらに、Tiを0.15％以上、Nbを0.05％
以上に多量に添加しても強度への影響が小さいことが判
る。The mechanical properties are the results of a tensile test in the rolling direction using a JIS No. 5 test piece of a sample taken from the position of 1 / 4w of the hot rolled coil in the pickling line. It can be seen that the steel obtained by the method of the present invention has good mechanical properties, whereas the alloys containing C and Mn added in excess have markedly deteriorated elongation. Furthermore, Ti is 0.15% or more, Nb is 0.05%.
It can be seen that the effect on strength is small even if added in a large amount.
【００３７】さらに酸洗ラインにて採取したサンプルの
耐食性を評価するため、促進型バクロ試験を実施した。
促進型バクロ試験は、通常のバクロ試験に加え、１回／
週、５％食塩水を散布することを特徴とする。Further, in order to evaluate the corrosion resistance of the sample collected on the pickling line, an accelerated bakuro test was carried out.
In addition to the usual bakuro test, the accelerated bakuro test is performed once
Characterized by spraying 5% saline solution weekly.
【００３８】この試験結果から、本発明で規定する範囲
より少ないCu添加量では耐食性の劣化が著しいことが判
る。また、耐食性向上に有効なＰ、Crについても、本発
明範囲を越えて多量に添加してもその効果が飽和するこ
とが判る。スケールロスについてもSiを多量に添加した
場合に、スケールロスが大きいことが判る。From these test results, it can be seen that the corrosion resistance is significantly deteriorated when the added amount of Cu is less than the range specified in the present invention. It is also found that the effects of P and Cr, which are effective in improving the corrosion resistance, are saturated even if added in a large amount beyond the range of the present invention. As for the scale loss, it can be seen that the scale loss is large when a large amount of Si is added.
【００３９】[0039]
【表１】 [Table 1]
【００４０】[0040]
【表２】 [Table 2]
【００４１】(実施例３)本例では、実施例１の場合と同
様にＣ＝0.10％、Mn＝0.50％、Ｓ＝0.015 ％の基本鋼組
成に、Cu＝0.2 、0.5 、0.8 ％をそれぞれ添加した３種
の鋼組成を持った素材鋼スラブ240t×1200ｗ×6000〜70
00L (mm)を作製し、圧延を実施したときの幅方向加工速
度と表面疵発生率の関係を調べた。(Example 3) In this example, as in the case of Example 1, the basic steel composition of C = 0.10%, Mn = 0.50% and S = 0.015% was added to Cu = 0.2, 0.5 and 0.8%, respectively. Material steel slab with three kinds of added steel composition 240t × 1200w × 6000〜70
00L (mm) was prepared and the relationship between the width direction processing speed and the surface defect occurrence rate when rolling was examined.
【００４２】スラブ幅方向の加工はサイジングプレスで
スラブ幅の圧下率で約20％(240 mm)実施した。また、ス
ラブ加熱温度は全て約1200℃とした。圧延は幅方向加工
後に粗圧延、タンデムの仕上げ圧延により板厚2.6 mmに
まで実施した。Processing in the slab width direction was carried out by a sizing press at a reduction rate of the slab width of about 20% (240 mm). Further, the slab heating temperature was all set to about 1200 ° C. After rolling in the width direction, rough rolling and tandem finish rolling were performed to a plate thickness of 2.6 mm.
【００４３】図２はこのときの加工温度と表面疵発生率
(%) との関係を表わすグラフである。図２のように幅方
向加工速度が早くなるに従い表面疵発生率が高くなるこ
とがわかる。さらにCu:0.50 ％以下では幅方向加工速度
が250 mm/sec以下では表面疵の発生が抑えられている。
逆にCu＝0.8 ％では幅方向加工速度が250mm/sec 以下で
も表面疵は、かなり発生する場合がある。FIG. 2 shows the processing temperature and the occurrence rate of surface defects at this time.
It is a graph showing the relationship with (%). As shown in FIG. 2, it can be seen that the surface flaw occurrence rate increases as the width direction processing speed increases. Furthermore, when Cu: 0.50% or less, surface flaws are suppressed when the width direction processing speed is 250 mm / sec or less.
On the other hand, when Cu = 0.8%, surface defects may occur considerably even when the processing speed in the width direction is 250 mm / sec or less.
【００４４】(実施例４)表３の含有成分の鋼(Ar3＝約80
0 ℃) を常法により溶製後、幅方向加工温度、加工量を
変化させて熱間圧延を行った。製造したスラブの寸法は
240t×1200ｗ×6000〜7000L(mm) とし、実施例３の場合
と同様に抽出後、スラブ幅方向の加工をサイジングプレ
スにより幅方向圧下率２％ (24mm) 〜20％(240mm) 、加
工速度 150〜350mm/sec で行い、その後粗圧延、Ar3 点
以上での仕上げ圧延、コイル巻取りを実施した。(Embodiment 4) Steel containing the components shown in Table 3 (Ar 3 = about 80)
(0 ° C.) was melted by a conventional method, and then hot rolling was performed while changing the width direction working temperature and the working amount. The dimensions of the manufactured slab are
240t x 1200w x 6000 to 7000L (mm), after extraction as in the case of Example 3, slab width processing is performed with a sizing press in the width direction rolling reduction of 2% (24mm) to 20% (240mm) and processing speed. The rolling was performed at 150 to 350 mm / sec, and then rough rolling, finish rolling with 3 or more points of Ar, and coil winding were performed.
【００４５】その結果を表４に示す。表面疵発生の有無
は、次工程である酸洗ラインにて目視による検査を行っ
た結果である。この結果より本発明方法で得られた熱延
鋼板の表面には疵が発生しないことが判る。また機械特
性は酸洗ラインにて熱延コイルの1/4wの位置より採取し
たサンプルをJIS ５号試験片にて圧延方向の引張試験を
行った結果である。The results are shown in Table 4. The presence or absence of surface flaws is the result of visual inspection in the next step, the pickling line. From this result, it can be seen that the surface of the hot-rolled steel sheet obtained by the method of the present invention has no flaws. The mechanical properties are the result of a tensile test in the rolling direction using a JIS No. 5 test piece of a sample taken from the position of 1 / 4w of the hot rolled coil in the pickling line.
【００４６】本発明方法により得られた鋼は良好な機械
特性を有しているのに対して、Ｃ、Mnを過剰に添加した
ものは、伸びの劣化が著しいことが判る。さらに、Ti、
Nbを1.0 ％以上に多量に添加しても強度への影響が小さ
いことが判る。It can be seen that the steel obtained by the method of the present invention has good mechanical properties, whereas the alloys containing C and Mn added in excess have markedly deteriorated elongation. In addition, Ti,
It can be seen that the effect on strength is small even if Nb is added in a large amount of 1.0% or more.
【００４７】さらに酸洗ラインにて採取したサンプルの
耐食性を評価するため、促進型バクロ試験を実施した。
促進型バクロ試験は、通常のバクロ試験に加え、１回／
週、５％食塩水を散布することを特徴とする。Further, in order to evaluate the corrosion resistance of the sample collected on the pickling line, an accelerated bakuro test was carried out.
In addition to the usual bakuro test, the accelerated bakuro test is performed once
Characterized by spraying 5% saline solution weekly.
【００４８】この試験結果から、本発明で規定する範囲
より少ないCu添加量では耐食性の劣化が著しいことが判
る。また、耐食性向上に有効なＰ、Crについても、本発
明範囲以上添加してもその効果が飽和することが判る。
スケールロスについてもSiを多量に添加した場合に、ス
ケールロスが大きいことが判る。From these test results, it is understood that the corrosion resistance is significantly deteriorated when the added amount of Cu is less than the range specified in the present invention. Further, it is understood that the effects of P and Cr, which are effective in improving the corrosion resistance, are saturated even if they are added within the range of the present invention.
As for the scale loss, it can be seen that the scale loss is large when a large amount of Si is added.
【００４９】[0049]
【表３】 [Table 3]
【００５０】[0050]
【表４】 [Table 4]
【００５１】[0051]
【発明の効果】本発明によれば高価なNiや加熱条件を大
きく制限することなく表面の良好な含鋼熱延鋼板を製造
することができる。Cu含有量が0.5 ％以下の場合、幅方
向加工を1170℃以上で実施するか、またはスラブ幅方向
加工速度を250mm/sec 以下とすることによりCuの脆化に
よる表面疵の発生を実質上完全に防止することができ
る。According to the present invention, a steel-containing hot-rolled steel sheet having a good surface can be manufactured without greatly limiting expensive Ni and heating conditions. When the Cu content is 0.5% or less, the width direction processing is performed at 1170 ° C or higher, or the slab width direction processing speed is set to 250 mm / sec or less to substantially complete the generation of surface defects due to Cu embrittlement. Can be prevented.
【図１】Cu含有量を変えた場合における鋼の幅方向加工
温度と表面疵発生率の関係を示すグラフである。FIG. 1 is a graph showing a relationship between a width direction working temperature of steel and a surface flaw occurrence rate when the Cu content is changed.
【図２】Cu含有量を変えた場合における鋼の幅方向加工
速度と表面疵発生率の関係を示すグラフである。FIG. 2 is a graph showing the relationship between the width direction working speed of steel and the surface flaw occurrence rate when the Cu content is changed.
Claims (3)
素材鋼スラブを加熱したのち、スラブ幅方向の加工をス
ラブ幅の４％以上行う場合、その加工を1170℃以上で実
施し、Ar3 点以上で仕上げ圧延を完了することを特徴と
する表面性状の良好な含銅熱延鋼板の製造方法。1. A raw material steel having a steel composition comprising C: 0.20% or less, Mn: 0.10 to 1.50%, S: 0.020% or less, Cu: 0.20 to 0.50%, and the balance being Fe and unavoidable impurities. After heating the slab, if processing in the slab width direction is performed at 4% or more of the slab width, the processing is performed at 1170 ° C or higher, and finish rolling is completed at Ar 3 points or more. Good surface quality. For producing a copper-containing hot rolled steel sheet.
素材鋼スラブを加熱したのち、スラブ幅方向の加工をス
ラブ幅の４％以上行う場合、その加工を幅方向の加工速
度(*1) 250mm/sec以下で実施し、Ar3 点以上で仕上げ圧
延を完了することを特徴とする表面性状の良好な含銅熱
延鋼板の製造方法。 加工速度(*1)＝ (元スラブ幅−加工後スラブ幅) ／幅方
向加工時間2. A raw steel slab having a steel composition comprising C: 0.20% or less, Mn: 0.10 to 1.50%, S: 0.020% or less, Cu: 0.20 to 0.50% with the balance being Fe and inevitable impurities. After heating the slab, if processing in the slab width direction is performed at 4% or more of the slab width, the processing is performed at a processing speed in the width direction (* 1) of 250 mm / sec or less, and finish rolling is completed with Ar 3 points or more. A method for producing a copper-containing hot-rolled steel sheet having good surface properties. Machining speed (* 1) = (original slab width-post-machining slab width) / width direction machining time
くとも１種、 および／またはＰ:0.15 ％以下、Cr:1.5％以下の少なく
とも１種以上を含有する請求項１または２記載の表面性
状の良好な含銅熱延鋼板の製造方法。3. The steel composition further comprises, by weight, at least one of Si: 1.2% or less, Ti: 0.15% or less, Nb: 0.05% or less, and / or P: 0.15% or less, Cr: 1.5. % Or less at least one or more kinds, The manufacturing method of the copper-containing hot-rolled steel sheet with favorable surface property of Claim 1 or 2.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8011091A JP2988355B2 (en) | 1995-07-25 | 1996-01-25 | Method for producing copper-containing hot-rolled steel sheet with good surface properties |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
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| JP7-189100 | 1995-07-25 | ||
| JP8011091A JP2988355B2 (en) | 1995-07-25 | 1996-01-25 | Method for producing copper-containing hot-rolled steel sheet with good surface properties |
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| Publication Number | Publication Date |
|---|---|
| JPH0994601A true JPH0994601A (en) | 1997-04-08 |
| JP2988355B2 JP2988355B2 (en) | 1999-12-13 |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002371337A (en) * | 2001-06-14 | 2002-12-26 | Nkk Corp | Cu-CONTAINING STEEL FOR WELD STRUCTURE SUPERIOR IN SURFACE PROPERTY, AND MANUFACTURING METHOD THEREFOR |
-
1996
- 1996-01-25 JP JP8011091A patent/JP2988355B2/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002371337A (en) * | 2001-06-14 | 2002-12-26 | Nkk Corp | Cu-CONTAINING STEEL FOR WELD STRUCTURE SUPERIOR IN SURFACE PROPERTY, AND MANUFACTURING METHOD THEREFOR |
| JP4608817B2 (en) * | 2001-06-14 | 2011-01-12 | Ｊｆｅスチール株式会社 | Cu-containing steel for welded structure having excellent surface properties and method for producing the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2988355B2 (en) | 1999-12-13 |
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