JPS6297702A - Production of steel sheet by hot reverse mill - Google Patents

Abstract

PURPOSE:To obtain a steel sheet having good quality at high efficiency by once coiling a thin steel ingot with a coiler and holding the coil, then un-coiling the steel sheet and rolling the sheet at a specific draft with hot reverse mills. CONSTITUTION:The thin steel ingot which is cast to >=20-<=80mm thickness by a continuous casting installation 1 is cut to a required length by a shearing machine 2 and is heated in a heating furnace 3 as necessary. The heated ingot is coiled by a coiler 4. The coiled ingot is held in a holding furnace 5 and is un-coiled by an un-coiler 6. The un-coiled ingot is rolled at >=40% and <=60% average draft by 2 stands of high-draft hot reverse mills 8. The mills 8 have a coiler 7 and an un-coiler 9 as ancillary equipment before and behind said mills. The thin steel ingot is rolled to the prescribed thickness during the time when the ingot is repeatedly rolled in forward and backward directions. The rolled sheet is coiled by a coiler 10.

Description

【発明の詳細な説明】 産業上の利用分野 本発明は、連続鋳造により鋳造された薄鋳片を一旦巻取
機で巻き取り、保熱後巻き戻し、熱間リバースミルで圧
延して良質の鋼板を高能率で製造する方法に関する。DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention involves rolling up a thin slab cast by continuous casting using a winder, rewinding it after heat retention, and rolling it using a hot reverse mill to obtain high quality. This invention relates to a method for manufacturing steel plates with high efficiency.

従来の技術 従来、連続鋳造鋳片から鋼板を製造するには、連続鋳造
された２００〜２５０−■厚程度の鋳片（スラブ）を直
ちに熱間圧延ミルで圧延して鋼板とするか、一旦冷却さ
れた鋳片を加熱炉で加熱した後圧延していた。Conventional technology Conventionally, in order to manufacture steel plates from continuously cast slabs, the continuously cast slabs with a thickness of about 200 to 250 mm are either immediately rolled into steel plates in a hot rolling mill, or they are first rolled into steel plates. The cooled slab was heated in a heating furnace and then rolled.

また特開昭５２−１（９５５０号公報のように、連続鋳
造設備により鋳造された鋳造材を直ちに所定厚さ以下に
圧延した後巻取機で巻き取り、該巻き取った鋳造材を連
続式の熱間仕上圧延ミルの入側で巻き戻し、該圧延ミル
で所要の寸法に圧延する粗圧延工程を省略した方法が提
案されている。In addition, as in JP-A No. 52-1 (9550), a cast material cast by continuous casting equipment is immediately rolled to a predetermined thickness or less, and then wound up by a winder, and the rolled casting material is transferred to a continuous casting method. A method has been proposed in which the rough rolling step of unwinding the material at the entry side of a hot finishing rolling mill and rolling it to a required dimension in the rolling mill is omitted.

あるいはまた、熱間化上連続ミルの替りに熱間リバース
ミルを用いる方法も行なわれており、例えば特開昭５７
−１７７８０６号公報では予備圧延用リバースミルと化
上圧延用リバースミルとを相前後して配置し、前記予備
圧延用リバースミルと化上圧延用リバースミルを単独駆
動からタンデム駆動に切換え可能とした装置が提案され
ている。Alternatively, a method of using a hot reverse mill instead of a continuous mill for hot heating has also been carried out;
- In Publication No. 177806, a reverse mill for preliminary rolling and a reverse mill for top rolling are arranged one after the other, and the reverse mill for preliminary rolling and the reverse mill for top rolling can be switched from independent drive to tandem drive. A device has been proposed.

発明の目的 しかしながら、上記従来の方法において、連続鋳造材か
ら鋼板を製造するＣＣホットストリップミルプロセスは
、断面の大きい鋳造材を用い、１〜６スタンドの粗圧延
ミルと６〜′ｌスタンドの仕上圧延ミルを用いた１５万
トン７月以上の生産規模を有する多量生産向きの方法で
あり、生産規模が１５万トン７月以下を対象とする場合
は、設備建設費および製造費が割高になるという問題が
ある。Purpose of the Invention However, in the above-mentioned conventional method, the CC hot strip mill process for manufacturing steel sheets from continuous casting materials uses casting materials with large cross sections, and involves a rough rolling mill of 1 to 6 stands and a finishing process of 6 to 1 stands. This method is suitable for mass production with a production scale of 150,000 tons or more using a rolling mill, and if the production scale is less than 150,000 tons in July, the equipment construction costs and manufacturing costs will be relatively high. There is a problem.

また、連続鋳造設備の出口で所定の厚さ以下に圧延した
後巻取機で巻き取った連続鋳造材を、巻き戻し、連続式
の熱間仕上圧延ミルで圧延する前記特開昭５２−８９５
５０号公報で提案された方法においては、前記熱間仕上
圧延ミルはタンデムミル、ゼ／ジミャ圧延ミルなどの連
続式圧延ミルのため、圧下率の上限に制約があり、生産
量に関係なく素材厚と製品厚から必要なスタンド数が決
まるので、生産規模が小さくても圧延設備の規模を大き
くせざるを得ないという問題がある。Further, in the above-mentioned Japanese Patent Application Laid-Open No. 52-895, the continuous casting material is rolled to a predetermined thickness or less at the exit of the continuous casting equipment, then wound up with a winder, and then unwound and rolled with a continuous hot finishing mill.
In the method proposed in Publication No. 50, since the hot finishing mill is a continuous rolling mill such as a tandem mill or a Ze/Jimya rolling mill, there is a restriction on the upper limit of the rolling reduction, and the material can be processed regardless of the production volume. Since the number of required stands is determined by the thickness and product thickness, there is a problem in that even if the production scale is small, the scale of the rolling equipment must be increased.

前記熱間リバースミルを用いる方法は、生産規模に合せ
た圧延設備とすることが可能で（コンパクトな設備とし
得るが、従来用いられている熱間リバースミルにおいて
は最終製品まで圧延するのに長時間を要し、圧延中の温
度降下が大きく、最終仕上り温度を確保できず、最悪の
場合には圧延途中で圧延不能の事態になることがある。In the method using the hot reverse mill, the rolling equipment can be adapted to the production scale (it can be a compact equipment, but in the conventional hot reverse mill, it takes a long time to roll the final product). It takes time, the temperature drop during rolling is large, the final finish temperature cannot be secured, and in the worst case, rolling may become impossible during rolling.

このため、ステツケルミルのようにミルの前後に保熱炉
を装備して、圧延中にコイルを加熱しながら圧延する方
式もあるが、この場合は製品表面にスケールが生成し、
製品の表面性状を著しく損ねる。従って、一般にリバー
スミルでは圧延可能最小製品厚およびコイル単重に制限
を受け、また、圧延に長時間を要するために圧延能率が
低く、生産性が悪いという問題がある。For this reason, some systems, such as the Stetskell mill, are equipped with heat retention furnaces before and after the mill to heat the coils during rolling, but in this case, scale forms on the product surface.
Significantly impairs the surface quality of the product. Therefore, reverse mills are generally limited by the minimum product thickness that can be rolled and the coil unit weight, and also have the problem of low rolling efficiency and poor productivity because rolling takes a long time.

本発明は５〜１５万ト／／月程度の生産規模に速した設
備により連続鋳造材から鋼板を製造する方法を提供する
ことを目的とする。An object of the present invention is to provide a method for manufacturing steel plates from continuous casting materials using equipment capable of achieving a production scale of about 50,000 to 150,000 tons/month.

発明の構成 本発明は上記目的をもってなされたものであって、その
要旨とするところは連続鋳造設備により鋳造された厚さ
２０ｍ−以上８０１■以下の薄鋳片を巻取機で巻き取り
、保熱した後巻き戻し、熱間リバースミルで平均圧下率
４０％以上６０％以下で圧延することを特徴とする鋼板
の製造方法にある。Structure of the Invention The present invention has been made for the above-mentioned purpose, and its gist is to wind up a thin cast piece with a thickness of 20 m or more and 801 cm or less cast by continuous casting equipment using a winding machine, and then to preserve it. A method for manufacturing a steel plate, which comprises heating, unwinding, and rolling with a hot reverse mill at an average reduction rate of 40% or more and 60% or less.

以下、図にもとづいて説明する。The explanation will be given below based on the figures.

第１図は、本発明法を実施するためのＨａの一例の構成
を示す説明図である。同図において、連続鋳造設備（１
）で鋳造された厚さ２０ＩＩ１１以上８０　ｍｖａ以下
の薄鋳片はせん断ａ■で所要の長さに切断され、必要に
応じて加熱炉（３）で加熱され、巻取機（４）で巻き取
られる。該巻き取られた薄鋳片は保熱炉（５）で保熱さ
れた後巻取機（６）により巻き戻され、２スタンドの高
圧下熱間リバースミル（８）で平均圧下率４０％以上６
０％以下で圧延される。該高圧下熱間リバースミル（８
）は、前後に付属設備として巻取・巻戻ＩＩ！■、（９
）を存し、前記薄鋳片は正方向および逆方向への繰り返
し圧延を受ける間に所定の厚さまで圧延され、巻取機Ｑ
（Ｉｔで巻き取られる。FIG. 1 is an explanatory diagram showing the configuration of an example of Ha for implementing the method of the present invention. In the same figure, continuous casting equipment (1
) Thin slabs with a thickness of 20 II 11 or more and 80 mva or less are cut to the required length by shearing a■, heated in a heating furnace (3) if necessary, and wound in a winder (4). taken. The rolled thin slab is heated in a heat retention furnace (5), then rewound by a winder (6), and then passed through a two-stand high-pressure hot reverse mill (8) at an average reduction rate of 40%. Above 6
Rolled at 0% or less. The high pressure hot reverse mill (8
) is equipped with winding/rewinding II as an accessory equipment at the front and rear! ■, (9
), the thin slab is rolled to a predetermined thickness while being repeatedly rolled in the forward and reverse directions, and
(It is wound up.

圧延用素材として２０１１以上８ｏ、ｍ以下の薄鋳片を
用いるのは、謎薄鋳片の連続鋳造設備の生産能力が１ス
トランド当り５〜１０万トン７月で、圧延設備を含めて
生産規模が比較的小さいプロセスに適しているためであ
る。The reason why we use thin slabs of 2011 or above and 8o and below 8m as rolling materials is a mystery.The continuous casting equipment for thin slabs has a production capacity of 50,000 to 100,000 tons per strand in July, and the production scale including the rolling equipment. This is because it is suitable for relatively small processes.

薄鋳片を鋳造後一旦巻取機に巻き取り、巻き戻して圧延
するのは次の理由による。すなわち、鋳造設備に直結し
た圧延設備で直ちにインラインで圧延する場合は、鋳造
速度に合せた速度で圧延しなければならず、圧延速度が
通常の圧延に比較して遅くなるため、圧延用ロールの表
面に肌荒れや亀甲状の割れが生ずる。また、圧延設備は
連続鋳造設備の各ストランド毎に一系列必要となり、生
産規模に比較して圧延設備の規模が大きくなる。The reason why a thin slab is wound up on a winding machine after casting, then unwound and rolled is as follows. In other words, when rolling is performed immediately in-line using a rolling equipment directly connected to the casting equipment, rolling must be performed at a speed that matches the casting speed, and the rolling speed is slower than normal rolling. Rough skin and tortoiseshell-like cracks occur on the surface. Further, one series of rolling equipment is required for each strand of the continuous casting equipment, and the scale of the rolling equipment becomes large compared to the production scale.

これに対し、一度巻取機に巻き取ってから巻き戻して圧
延すると、連続鋳造設備と圧延設備をそれぞれ独立して
稼動させ得るため、圧延速度を鋳造速度に合せる必要が
なく、インラインで圧延する場合に生ずる前記の問題は
起らない。また、一般に圧延能力は鋳造能力に比較して
２〜３倍あるため、連続鋳造設備２ストランドに対して
圧延設備は１系列とすることが可能で、該圧延設備をコ
ンパクトにし得る。On the other hand, if the winding is done once on a winder and then rewound and rolled, the continuous casting equipment and rolling equipment can be operated independently, so there is no need to match the rolling speed to the casting speed, and rolling can be done in-line. The above-mentioned problem that occurs in the case does not occur. Furthermore, since the rolling capacity is generally two to three times as large as the casting capacity, it is possible to use one series of rolling equipment for two strands of continuous casting equipment, and the rolling equipment can be made compact.

次に、圧延に高圧下熱間リバースミルを用いるのは、生
産規模に合せた圧延設備で能率よく圧延することができ
るからである。ここに高圧下熱間リバースミルとは１バ
ス当り圧下率４０％以上の圧下が可能である熱間リバー
スミルをいう。連続式圧延ミルの圧下率は４０％未清で
あるから、例えば厚さ５０龍の鋳片から厚さ２■■の鋼
板を製造する場合、最低４スタンドの圧延ミルが必要に
なるように、素材厚と製品厚から必要な圧延ミルのスタ
ンド数が決まるため、生産規模に関係なく圧延設備の規
模を大きくせざるを得ないが、熱間リバースミルを用い
ると、生産規模に合せた圧延設備の設置が可能であり、
連続式圧延ミルに比較して少ないスタンド数で所定厚さ
の鋼板を製造することができる。しかも、高圧下リバー
スミルを使用することにより、前記従来の熱間リバース
ミルの欠点、−すなわち圧延に長時間を要することによ
る温度降下を避け、厚さ１．２　ａｍ　、重Ｊｌｉ３０
）ンの大単重コイルを製造することが可能になる。Next, the reason why a high-pressure hot reverse mill is used for rolling is that rolling can be carried out efficiently using rolling equipment that is suited to the production scale. Here, the term "hot reverse mill under high pressure" refers to a hot reverse mill that is capable of rolling down at a rolling reduction rate of 40% or more per bath. Since the rolling reduction rate of a continuous rolling mill is 40%, for example, when producing a 2mm thick steel plate from a 50mm thick slab, a rolling mill with at least 4 stands is required. The number of rolling mill stands required is determined by the material thickness and product thickness, so the scale of the rolling equipment must be increased regardless of the production scale. However, if a hot reverse mill is used, the rolling equipment can be adjusted to match the production scale. It is possible to install
A steel plate of a predetermined thickness can be manufactured with fewer stands than a continuous rolling mill. Moreover, by using a high-pressure reverse mill, the drawbacks of the conventional hot reverse mill, i.e., the temperature drop due to the long time required for rolling, can be avoided, and the
) It becomes possible to manufacture large unit weight coils.

高圧下熱間リバースミルの平均圧下率の下限を４０％と
したのは、圧下率が４０％に溝たない場合、圧延バス回
数が多くなり、鋼板の仕上り温度が降下して薄い鋼板の
製造が困難となるためである。また上限を６０％とした
のは、圧下率が６０％を超えると、ロールの必耗、肌荒
れがＷｎ箸になり、同時に製品の断面形伏の制御が困難
になるためである。The lower limit of the average rolling reduction rate of the hot reverse mill under high pressure was set at 40% because if the rolling reduction rate does not reach 40%, the number of rolling baths will increase, the finishing temperature of the steel plate will drop, and thin steel plates will be manufactured. This is because it becomes difficult. The upper limit was set at 60% because if the rolling reduction exceeds 60%, roll wear and roughness will occur, and at the same time, it will be difficult to control the cross-sectional shape of the product.

実　　　施　　　例 以下、実施例にもとづいて説明する。Example The following is a description based on examples.

高圧下熱間リバースミルを使用し、第１図に示した構成
の装置により厚さ５０謹■の薄鋳片を厚さ１、２鴎、単
ｆｆｔ３０）ンのコイルに圧延した。比較のため通常の
熱間リバースミルを用いた場合についても実施した。第
１表に圧延の実施諸元を示す。Using a hot reverse mill under high pressure and an apparatus having the configuration shown in FIG. 1, a thin cast slab with a thickness of 50 mm was rolled into a coil with a thickness of 1 to 2 mm and a single thickness of 30 mm. For comparison, a case using a normal hot reverse mill was also conducted. Table 1 shows the rolling specifications.

圧延所要時間、圧延開始温度、最終仕上り温度および圧
延能率を第２表に示す。同表から通常の熱間リバースミ
ルを用いた従来法では最終仕上り温度が必要温度である
８５０℃以下であるのに対し、高圧下熱間リバースミル
を用いた本発明法では８８０℃と十分の温度を存してお
り、しかも圧延能率は従来法に比べ約５″ＭｒＪ増の２
５０７／Ｈを示すことがわかる。Table 2 shows the required rolling time, rolling start temperature, final finishing temperature, and rolling efficiency. The table shows that in the conventional method using a normal hot reverse mill, the final finishing temperature is below the required temperature of 850°C, whereas in the method of the present invention using a hot reverse mill under high pressure, it is a sufficient temperature of 880°C. In addition, the rolling efficiency is approximately 5″MrJ higher than that of the conventional method.
507/H.

第　　１　　表 第２表 ※　必要な最終仕上り温度：８５０℃以上発明の効果 以上述べたように、連続鋳造により鋳造される薄鋳片を
一旦巻取機で巻き皐り、保熱後巻き戻し、高圧下熱間リ
バースミルで平均圧下率４０％以上６０％以下で圧延す
る本発明の方法により、生産規模が比較的小さい場合で
あっても、従来のｆＡ　Ｒ１リバースミルでは実現でき
ない大単重のコイルを高能率で製造することができる。Table 1 Table 2* Required final finishing temperature: 850°C or higher Effects of the invention As mentioned above, the thin slab cast by continuous casting is once rolled and scorched using a winder, and after heat retention, it is rewound. By the method of the present invention, which involves rolling with a hot reverse mill under high pressure at an average reduction rate of 40% to 60%, even when the production scale is relatively small, it is possible to achieve large unit weights that cannot be achieved with the conventional fA R1 reverse mill. Coils can be manufactured with high efficiency.

【図面の簡単な説明】[Brief explanation of drawings]

第１図は本発明法を実施するための装置の一例の構成を
示す説明図である。 ｌ・・・連続鋳造設備　２・・・せん断機３・・・加熱
炉　　　　４・・・巻取機５・・・保熱炉　　　　６・
・・巻戻機７・・・巻取・巻戻ｆｉ８・・・高圧下熱間
リバースミル９・・・巻取ｅ巻戻機　■０・・・巻取機
第１図FIG. 1 is an explanatory diagram showing the configuration of an example of an apparatus for carrying out the method of the present invention. l... Continuous casting equipment 2... Shearing machine 3... Heating furnace 4... Winding machine 5... Heat retention furnace 6.
... Rewinding machine 7 ... Winding/unwinding fi 8 ... High-pressure hot reverse mill 9 ... Winding e-unwinding machine ■0 ... Winding machine Fig. 1

Claims (1)

【特許請求の範囲】[Claims] 連続鋳造設備により鋳造された厚さ２０ｍｍ以上８０ｍ
ｍ以下の薄鋳片を巻取機で巻き取り、保熱した後巻き戻
し、熱間リバースミルで平均圧下率４０％以上６０％以
下で圧延することを特徴とする鋼板の製造法。Cast with continuous casting equipment, thickness 20mm or more, 80m
A method for producing a steel plate, which comprises winding a thin cast slab of 500 m or less in diameter using a winder, rewinding it after heat retention, and rolling it in a hot reverse mill at an average reduction rate of 40% or more and 60% or less.