JP3356084B2 - Continuous casting method of beam blank - Google Patents
Continuous casting method of beam blankInfo
- Publication number
- JP3356084B2 JP3356084B2 JP32624898A JP32624898A JP3356084B2 JP 3356084 B2 JP3356084 B2 JP 3356084B2 JP 32624898 A JP32624898 A JP 32624898A JP 32624898 A JP32624898 A JP 32624898A JP 3356084 B2 JP3356084 B2 JP 3356084B2
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- JP
- Japan
- Prior art keywords
- slab
- rolling
- reduction
- center
- roll
- 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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Description
【０００１】[0001]
【発明の属する技術分野】本発明は、中心偏析およびセ
ンターポロシティがなく、かつ内部割れの発生もない、
内部品質に優れたビームブランクを製造することができ
る鋼の連続鋳造方法に関する。BACKGROUND OF THE INVENTION The present invention relates to a method for producing a composite material, which is free from center segregation and center porosity and free from internal cracks.
The present invention relates to a method for continuously casting steel capable of producing a beam blank having excellent internal quality.
【０００２】[0002]
【従来の技術】建築用材料などに使用されるＨ形鋼の製
造では、製造コストの削減を目的に、加熱炉での素材の
加熱効率の向上、圧延工程での圧延パス回数の削減など
が図られてきた。そのため、素材のビームブランクを、
スラブまたはブルームなどの連続鋳造鋳片から連続鋳造
機内で圧下して製造する方法が提案されている。2. Description of the Related Art In the production of H-section steels used for building materials, for the purpose of reducing production costs, it is necessary to improve the efficiency of heating materials in a heating furnace and reduce the number of rolling passes in a rolling process. It has been planned. Therefore, beam blank of material,
2. Description of the Related Art A method has been proposed in which a continuous cast slab such as a slab or a bloom is rolled down in a continuous caster for production.
【０００３】一方、建築物の高層化や耐震化にともな
い、Ｈ形鋼の高強度化、高品質化が要求されるようにな
ってきた。Ｈ形鋼に要求されるこのような特性を満たす
ために、その素材であるビームブランクに対して、中心
偏析やセンターポロシティのない、かつ内部割れのな
い、優れた内部品質が求められる。[0003] On the other hand, with the rise of buildings and earthquake resistance of buildings, H-section steels are required to have higher strength and higher quality. In order to satisfy such characteristics required for the H-section steel, the beam blank as the material thereof is required to have excellent internal quality without center segregation or center porosity and without internal cracks.
【０００４】鉄と鋼、６７（１９８１）８、Ｐ２８４に
は、ビームブランクの横断面形状をした鋳片を連続鋳造
により直接製造する方法が提案されている。しかし、こ
の方法では、鋳片の中心部近傍に中心偏析やセンターポ
ロシティが発生する場合がある。[0004] For iron and steel, 67 (1981) 8, P284, a method for directly producing a slab having a cross section of a beam blank by continuous casting has been proposed. However, in this method, center segregation or center porosity may occur near the center of the slab.
【０００５】中心偏析とは、鋳片の厚み方向中心部に
Ｃ、Ｓ、Ｐ、Ｍｎなどの偏析成分が濃化した状態のこと
である。凝固の進行に伴い偏析成分の濃化した溶鋼が、
凝固の際の収縮などにより最終凝固部である鋳片の厚み
中心部に移動、集積し、そのまま凝固することにより発
生する。[0005] Center segregation refers to a state in which segregation components such as C, S, P, and Mn are concentrated at the center in the thickness direction of a slab. As the solidification progresses, the molten steel with the segregated components concentrated,
It is generated by moving and accumulating at the center of the thickness of the slab, which is the final solidified portion, due to shrinkage at the time of solidification and solidifying as it is.
【０００６】ポロシティとは、偏析成分の濃化した溶鋼
は最終凝固部では流動しにくいので、収縮によって生じ
る狭い隙間に溶鋼が補給されずに凝固が完了するために
発生する孔のことである。The porosity is a hole generated when solidification is completed without molten steel being replenished in a narrow gap caused by shrinkage because molten steel in which segregated components are concentrated hardly flows in a final solidified portion.
【０００７】したがって、これら中心偏析やポロシティ
の防止対策として、偏析成分の濃化した溶鋼の移動、集
積を抑制するため、最終凝固部近傍の鋳片の未凝固部を
ロールなどで圧下するのが有効である。[0007] Therefore, as a countermeasure against these center segregation and porosity, in order to suppress the movement and accumulation of the molten steel in which the segregated components are concentrated, the unsolidified part of the slab near the final solidified part is rolled down with a roll or the like. It is valid.
【０００８】特開平８−２８１３０１号公報には、横断
面形状が矩形のブルーム連続鋳造機の後端にユニバーサ
ル圧延機を設置して、鋳片の未凝固部を圧下することに
よりビームブランクを製造する方法が提案されている。
しかし、この方法では、圧下開始時期や圧下量が適切で
ないと、圧下後のビームブランクに中心偏析やセンター
ポロシティが発生したり、さらに、内部割れが発生する
という問題がある。Japanese Unexamined Patent Publication No. Hei 8-281301 discloses a method of manufacturing a beam blank by installing a universal rolling mill at a rear end of a bloom continuous caster having a rectangular cross section and rolling down an unsolidified portion of a slab. A way to do that has been proposed.
However, in this method, if the rolling start time and the rolling amount are not appropriate, there is a problem that center segregation and center porosity occur in the beam blank after rolling, and further, internal cracks occur.
【０００９】[0009]
【発明が解決しようとする課題】本発明は、中心偏析お
よびセンターポロシティがなく、かつ内部割れの発生も
ない、内部品質に優れたビームブランクを製造すること
が可能な連続鋳造方法を提供することを目的とする。SUMMARY OF THE INVENTION It is an object of the present invention to provide a continuous casting method capable of producing a beam blank having no center segregation and center porosity and having no internal cracks and having excellent internal quality. With the goal.
【００１０】[0010]
【課題を解決するための手段】本発明の要旨は、ビーム
ブランクの連続鋳造方法に関し、一対の水平ロールおよ
び一対の垂直ロールを備える少なくとも１台の圧下装置
を用いて、内部に未凝固部が存在する断面形状が矩形の
鋳片を、上下および左右方向から圧下することによりビ
ームブランクを製造する方法において、圧下開始時期を
圧下位置における鋳片の中心固相率が０．３以上０．９
８未満の間とし、下記（Ａ）式で表される圧下形状比α
が１．２以上５．８以下となる条件で圧下することにあ
る。SUMMARY OF THE INVENTION The gist of the present invention relates to a continuous casting method of a beam blank, in which an unsolidified portion is internally formed by using at least one reduction device having a pair of horizontal rolls and a pair of vertical rolls. In a method of manufacturing a beam blank by reducing an existing slab having a rectangular cross-sectional shape in vertical and horizontal directions, the reduction start time is set such that the center solid phase ratio of the slab at the reduction position is 0.3 or more and 0.9 or less.
The rolling reduction ratio α is expressed by the following formula (A).
Is to be reduced under the condition that is not less than 1.2 and not more than 5.8.
【００１１】 α ＝ （Ｄ・Ｒ）0.5／Ｌ ・・・（Ａ） ここで、Ｄ：水平ロールの直径（ｍｍ） Ｒ：水平ロールによる鋳片の圧下量（ｍｍ） Ｌ：圧下位置における鋳片内の固相率０．９９の凝固界
面間の圧下方向の未凝固部の厚み（ｍｍ） 一対の水平ロールおよび一対の垂直ロールを備えた圧下
装置を用いる理由は、たとえば、一対の水平ロールで鋳
片の長辺の幅中央部近傍を圧下して、矩形断面形状の鋳
片をビームブランクに成形する場合に、鋳片の短辺が外
側に膨らむのを、水平ロールと同一断面または水平ロー
ルよりも鋳造方向で下流側にある一対の垂直ロールによ
り押さえるためである。Α = (D · R) 0.5 / L (A) where D: diameter of horizontal roll (mm) R: reduction amount of cast slab by horizontal roll (mm) L: casting at reduction position The thickness (mm) of the unsolidified portion in the rolling direction between the solidification interfaces having a solid phase ratio of 0.99 in the piece (mm) The reason for using a rolling device having a pair of horizontal rolls and a pair of vertical rolls is, for example, a pair of horizontal rolls. In the case of shaping the slab having a rectangular cross-section into a beam blank by pressing down the vicinity of the center of the width of the long side of the slab in the beam blank, the short side of the slab bulges outward, the same cross section as the horizontal roll or horizontal This is because a pair of vertical rolls located downstream of the rolls in the casting direction hold down the rolls.
【００１２】内部に未凝固部が存在する鋳片を圧下する
のは、圧下する際の圧下力が小さくて済むことの他に、
中心偏析やセンターポロシティ（以下、ポロシティと記
す）のないビームブランクを得るためである。[0012] The reduction of the slab having an unsolidified portion inside is not only because the rolling force at the time of reduction is small, but also.
This is for obtaining a beam blank without center segregation or center porosity (hereinafter, referred to as porosity).
【００１３】鋳片の未凝固部を圧下する場合に、圧下開
始時の鋳片の中心固相率を適正な範囲の値にすれば、中
心偏析やポロシティを発生させることがなく、内部品質
のよいビームブランクを得ることができる。すなわち、
圧下開始時の鋳片の中心固相率が適正な範囲の値である
と、圧下後にはほとんど未凝固部が残存せず、したがっ
て、圧下後に鋳片の中心部が完全に凝固する過程で、中
心偏析やポロシティは生成しない。なお、鋳片の中心固
相率は、鋳片の厚み中心部の温度を伝熱凝固解析により
計算して求め、これと、その鋼に固有の液相線温度およ
び固相線温度などから求めることができる。When the unsolidified portion of the slab is rolled down, if the center solid phase ratio of the slab at the start of rolling is set to a value within an appropriate range, center segregation and porosity do not occur, and the internal quality is reduced. Good beam blanks can be obtained. That is,
If the center solid phase ratio of the slab at the start of rolling is a value in an appropriate range, almost no unsolidified portion remains after rolling, and therefore, in the process of completely solidifying the central portion of the slab after rolling, No central segregation or porosity is generated. In addition, the center solid phase ratio of the slab is obtained by calculating the temperature at the center of the thickness of the slab by heat transfer solidification analysis, and from this, the liquidus temperature and the solidus temperature specific to the steel. be able to.
【００１４】鋳片の未凝固部を圧下する際に、上記
（Ａ）式で表される圧下形状比αの値を適正な範囲とす
る。これにより、鋳片を圧下する際に、内部割れを発生
させることなく、中心偏析やポロシティのないビームブ
ランクを得ることができる。この圧下形状比αを適正な
範囲の値にするという意味は、圧下開始時の鋳片の未凝
固厚みＬに対して、適正な圧下ロールの直径Ｄとする
か、適正な圧下量Ｒとするか、または圧下ロールの直径
Ｄと圧下量ＲをかけたＤ・Ｒを適正な値とするかを意味
する。すなわち、このような圧下形状比αの条件で圧下
すれば、圧下を受ける凝固界面に圧縮応力が作用するの
で、内部割れが発生しにくくなる。さらに、圧下により
未凝固部の溶鋼の流動が強められるために、凝固界面近
傍の柱状晶間に吸引された偏析成分が濃化した溶鋼が、
鋳造方向の上流側に絞り出されやすくなり、中心偏析や
ポロシティが発生しにくくなる。When the unsolidified portion of the slab is reduced, the value of the reduced shape ratio α represented by the above formula (A) is set to an appropriate range. This makes it possible to obtain a beam blank free from center segregation and porosity without causing internal cracks when the slab is reduced. Making the rolling shape ratio α a value within an appropriate range means that the unrolled thickness L of the slab at the start of rolling is set to a proper rolling roll diameter D or a proper rolling amount R. Or a value obtained by multiplying the diameter D of the reduction roll by the reduction amount R to an appropriate value. That is, when the rolling is performed under the condition of the rolling shape ratio α, a compressive stress acts on the solidification interface that receives the rolling, so that an internal crack is less likely to occur. Furthermore, since the flow of the molten steel in the unsolidified portion is strengthened by the reduction, the molten steel in which the segregated components sucked between the columnar crystals near the solidification interface are concentrated,
It is easy to squeeze out to the upstream side in the casting direction, so that center segregation and porosity do not easily occur.
【００１５】なお、（Ａ）式の右辺の一部を変形した
（Ｄ・Ｒ／２）0.5 は、圧下ロールと鋳片の投影接触長
さを示す式である。接触投影長さとは、圧延理論で一般
的に用いられている概念である。したがって、圧下形状
比αは、投影接触長さを未凝固部の厚みで除したものに
係数を掛けた式であることを意味する。(D · R / 2) 0.5 in which a part of the right side of the formula (A) is deformed is a formula indicating the projected contact length between the rolling roll and the slab. The contact projection length is a concept generally used in rolling theory. Therefore, the rolling shape ratio α means that the projection contact length is divided by the thickness of the unsolidified portion and multiplied by a coefficient.
【００１６】[0016]
【発明の実施の形態】図１は、本発明の方法を実施する
ための連続鋳造装置の構成を示す図である。FIG. 1 is a diagram showing the configuration of a continuous casting apparatus for carrying out the method of the present invention.
【００１７】鋳型４から連続的に引き抜かれた断面形状
が矩形の鋳片１は、二次冷却帯５で水冷却され、次い
で、ガイドロール６を経て、ピンチロール７により引き
抜かれる。その後、上下および左右方向から圧下できる
ように一対の水平ロールおよび一対の垂直ロールを備
え、ピンチロールの後段に設置された未凝固圧下装置９
により、鋳片は圧下される。The slab 1 having a rectangular cross section continuously drawn from the mold 4 is water-cooled in the secondary cooling zone 5, and then pulled out by the pinch roll 7 through the guide roll 6. Thereafter, a non-solidification rolling device 9 provided with a pair of horizontal rolls and a pair of vertical rolls so as to be able to be rolled down from up and down and right and left directions is provided at the subsequent stage of the pinch roll.
As a result, the slab is reduced.
【００１８】鋳片を上下および左右方向から圧下する際
に、図１に示すように同時に圧下してもよいし、上下方
向から圧下するロールと左右方向から圧下するロールが
鋳造方向に隣り合わせる程度に間隔をあけて圧下しても
構わない。When the slab is lowered from the vertical and horizontal directions, the slab may be lowered simultaneously as shown in FIG. 1, or the rolls which are lowered from the vertical direction and the rolls which are lowered from the horizontal direction are adjacent to each other in the casting direction. The pressure may be reduced at intervals.
【００１９】図２は、断面形状が矩形の鋳片を未凝固圧
下したときの鋳片の横断面形状を模式的に示す図であ
る。鋳片内部に未凝固部８を含む鋳片を、鋳片の幅より
も狭い胴幅の一対の水平ロール２−１および２−２、さ
らに一対の垂直ロール３−１および３−２で、上下およ
び左右方向から同時に未凝固圧下し、ビームブランク１
０に成形する。ただし、垂直ロール３−１および３−２
では、鋳片の膨らみを押さえる程度の圧下を行う。FIG. 2 is a view schematically showing a cross-sectional shape of a slab when a slab having a rectangular cross-sectional shape is unsolidified and reduced. The slab including the unsolidified portion 8 in the slab is formed by a pair of horizontal rolls 2-1 and 2-2 having a body width smaller than the width of the slab, and a pair of vertical rolls 3-1 and 3-2. Unsolidified pressure is simultaneously reduced from the top and bottom and left and right directions.
Mold to 0. However, the vertical rolls 3-1 and 3-2
Then, the reduction is performed to the extent that the swelling of the slab is suppressed.
【００２０】鋳片の未凝固部を圧下する際に、圧下開始
時の鋳片の中心固相率は０．３〜０．９８未満とする。When the unsolidified portion of the slab is reduced, the center solid fraction of the slab at the start of the reduction is set to 0.3 to less than 0.98.
【００２１】中心固相率が０．３未満では、圧下後に残
存する未凝固部の厚みが厚くなり、その後に凝固が進行
する過程で、再び中心偏析やポロシティが生成する。ま
た、後述するように、圧下形状比αを適正な範囲の値と
して内部割れの発生を防止するため、ロールの直径Ｄま
たは鋳片の圧下量Ｒを大きくすることとなり、設備が過
大となる。また、中心固相率が０．９８以上に大きい場
合には、圧下の際の圧下ロールの負荷が大きくなり、圧
下できないか、または、鋳片の引き抜きができなくな
る。If the central solid phase ratio is less than 0.3, the thickness of the unsolidified portion remaining after the reduction becomes large, and the center segregation and porosity are generated again in the process of solidification progressing thereafter. Further, as described later, in order to prevent the occurrence of internal cracks by setting the rolling shape ratio α to a value within an appropriate range, the diameter D of the roll or the rolling amount R of the slab is increased, and the equipment becomes excessively large. On the other hand, when the center solid fraction is greater than 0.98, the load of the rolling roll during rolling is large, and the rolling cannot be performed or the slab cannot be pulled out.
【００２２】鋳片の未凝固部を圧下する際に、圧下形状
比αを１．２〜５．８とする。When the unsolidified portion of the slab is reduced, the reduced shape ratio α is set to 1.2 to 5.8.
【００２３】図３は、鋳片を圧下後のビームブランクに
残存するセンターポロシティの最大径に及ぼす圧下形状
比αの影響を示す図である。圧下形状比αが１．２以上
でポロシティの最大径は実害がない程度に小さくなり、
ポロシティの発生が顕著に抑制され、１．５以上でポロ
シティは消滅している。FIG. 3 is a diagram showing the effect of the rolling shape ratio α on the maximum diameter of the center porosity remaining in the beam blank after the slab is rolled. When the rolling shape ratio α is 1.2 or more, the maximum diameter of porosity becomes small to the extent that there is no actual harm,
The occurrence of porosity is remarkably suppressed, and the porosity disappears at 1.5 or more.
【００２４】図４は、圧下後のビームブランクに発生し
た内部割れの最大長さに及ぼす圧下形状比αの影響を示
す図である。圧下形状比が０〜１の間の特定の値で内部
割れの長さが最大となるが、圧下形状比が１．２以上
で、内部割れの発生は抑制され、１．５以上では発生し
なくなる。FIG. 4 is a diagram showing the effect of the reduced shape ratio α on the maximum length of internal cracks generated in the beam blank after the reduction. The length of the internal crack is maximized at a specific value of the reduction shape ratio between 0 and 1. However, when the reduction shape ratio is 1.2 or more, the occurrence of internal cracks is suppressed. Disappears.
【００２５】圧下形状比が５．８を超えると、圧下ロー
ルへの負荷が大きくなりすぎて、圧下できないか、また
は、鋳片の引き抜きが困難になるので、圧下形状比は
５．８以下とする。圧下ロールへの負荷を、さらに減ら
すためには、４．５以下が望ましい。If the reduction shape ratio exceeds 5.8, the load on the reduction roll becomes too large, and the reduction cannot be performed, or it becomes difficult to pull out the slab. Therefore, the reduction shape ratio is 5.8 or less. I do. In order to further reduce the load on the reduction roll, 4.5 or less is desirable.
【００２６】これらの観点から、圧下形状比αは１．２
〜５．８とする。また、１．５〜４．５が望ましい。From these viewpoints, the reduction shape ratio α is 1.2
To 5.8. Moreover, 1.5-4.5 is desirable.
【００２７】水平ロールの直径は、２００〜１２００ｍ
ｍが望ましい。２００ｍｍ未満の場合には、圧下力の内
部浸透性が低いため、中心偏析やポロシテイなどの改善
効果が十分でない。また、１２００ｍｍを超えると、大
きな圧下力を必要とするので未凝固圧下装置が大型化
し、設備費用が上昇する。The diameter of the horizontal roll is 200 to 1200 m
m is desirable. If it is less than 200 mm, the internal permeability of the rolling force is low, and the effect of improving center segregation and porosity is not sufficient. On the other hand, if it exceeds 1200 mm, a large rolling force is required, so that the size of the unsolidified rolling device is increased, and the equipment cost is increased.
【００２８】水平ロール２−１、２−２のロール形状は
両端が丸みを有し、その他の部分はフラットな形状と
し、また、垂直ロール３−１、３−２のロール形状は、
膨らみを押さえるためフラットな形状とし、ロールの胴
幅は鋳片の厚みより広くするのが望ましい。The roll shape of the horizontal rolls 2-1 and 2-2 is round at both ends and the other portions are flat. The roll shapes of the vertical rolls 3-1 and 3-2 are as follows.
It is preferable that the roll has a flat shape so as to suppress the bulging, and the body width of the roll is wider than the thickness of the slab.
【００２９】未凝固圧下装置の装置数は、とくに限定し
ないが、多段に設けることは設備が大型化することか
ら、通常は１段だけとするのが望ましい。多段の未凝固
圧下装置を用いる場合には、それぞれの未凝固圧下装置
において、上述した適正な圧下開始時期の鋳片の中心固
相率および適正な圧下形状比の条件を満たすように圧下
するのがよい。Although the number of unsolidified rolling devices is not particularly limited, it is usually desirable to provide only one stage since providing the devices in multiple stages increases the size of the equipment. In the case of using a multi-stage unsolidified rolling device, in each unsolidified rolling device, the rolling is performed so as to satisfy the conditions of the above-described center solid phase ratio of the slab and the proper rolling shape ratio at the proper rolling start timing. Is good.
【００３０】[0030]
【実施例】図１に示す装置構成の連続鋳造機を用いて、
断面形状が厚み３００ｍｍ、幅６５０ｍｍの矩形のブル
ームを鋳造し、ブルームの未凝固部を水平ロールで圧下
して、ビームブランクを製造した。DESCRIPTION OF THE PREFERRED EMBODIMENTS Using a continuous casting machine having an apparatus configuration shown in FIG.
A rectangular bloom having a cross section of a thickness of 300 mm and a width of 650 mm was cast, and an unsolidified portion of the bloom was pressed down with a horizontal roll to produce a beam blank.
【００３１】用いた鋼は、Ｃ含有率が０．１０重量％
で、鋳型直下から６ｍまでの間を０．１〜２．０リット
ル／ｋｇ・鋼の比水量の条件で二次冷却した。鋳造速度
を０．８〜１．７ｍ／分の範囲で変化させ、圧下開始時
の未凝固部の厚みおよび中心固相率を変えた。The steel used had a C content of 0.10% by weight.
The secondary cooling was performed under the conditions of a specific water amount of 0.1 to 2.0 liters / kg · steel from immediately below the mold to 6 m. The casting speed was changed in the range of 0.8 to 1.7 m / min, and the thickness of the unsolidified portion and the center solid phase ratio at the start of reduction were changed.
【００３２】未凝固部の厚みは、半径方向一次元の非定
常伝熱解析により求めるとともに、鋳造中に溶鋼にＦｅ
Ｓを添加して調査した。両者から求められた未凝固部の
厚みはよく一致した。鋳片の中心固相率は、鋳片中心部
の温度を伝熱凝固解析により計算するとともに、その鋼
に固有の液相線温度および固相線温度などから求めた。The thickness of the unsolidified portion is determined by a one-dimensional unsteady heat transfer analysis in the radial direction.
The addition of S was investigated. The thickness of the unsolidified portion obtained from both of them was in good agreement. The center solidus fraction of the slab was obtained by calculating the temperature at the center of the slab by heat transfer solidification analysis and from the liquidus temperature and solidus temperature specific to the steel.
【００３３】未凝固圧下装置は、１台のスタンドとし、
溶鋼のメニスカスから２４ｍの距離に配置した。水平ロ
ールのロール径は３００、６００、１０００ｍｍの３種
類、ロールの胴幅は４３０ｍｍで、ロールのコーナー部
に半径５〜５０ｍｍの丸みを持たせた。水平ロールによ
る圧下量は、２０〜９０ｍｍの範囲で試験した。The unsolidified rolling device is a single stand,
It was arranged at a distance of 24 m from the meniscus of the molten steel. The horizontal roll had three types of roll diameters of 300, 600 and 1000 mm, the roll had a body width of 430 mm, and the corners of the roll were rounded with a radius of 5 to 50 mm. The amount of reduction by the horizontal roll was tested in the range of 20 to 90 mm.
【００３４】垂直ロールのロール径は４００ｍｍ、ロー
ルの胴幅は３５０ｍｍで、ロールの表面はフラットな形
状とした。水平ロールで鋳片の長辺を圧下する際に、垂
直ロールで鋳片の短辺を押さえて、鋳片の短辺が膨らむ
のを防止した。The roll diameter of the vertical roll was 400 mm, the roll width was 350 mm, and the surface of the roll was flat. When rolling down the long side of the slab with the horizontal roll, the short side of the slab was pressed with the vertical roll to prevent the short side of the slab from expanding.
【００３５】鋳造速度が一定となった後、鋳造方向に長
さ約２ｍのビームブランクを採取し、鋳造方向に１００
ｍｍの間隔で２０個の横断面サンプルを切り出した。After the casting speed became constant, a beam blank having a length of about 2 m was sampled in the casting direction, and 100 mm in the casting direction.
Twenty cross-sectional samples were cut out at mm intervals.
【００３６】ポロシティについては、横断面サンプル内
のポロシティの発生個数と形状を目視観察し、さらに寸
法を計測した。ポロシティ総面積は、形状を円または楕
円形状に近似し、計測した寸法から１個のポロシティ面
積を求め、これらを合計して求めた。このポロシティ総
面積と横断面サンプル面積との比をポロシティ面積率
（％）として評価した。１０個の横断面サンプルを調査
して、その結果を平均して求めた。Regarding the porosity, the number and shape of porosity generated in the cross section sample were visually observed, and the dimensions were measured. The porosity total area was obtained by approximating the shape to a circle or an ellipse, obtaining one porosity area from the measured dimensions, and summing these. The ratio of the porosity total area to the cross-sectional sample area was evaluated as a porosity area ratio (%). Ten cross-sectional samples were investigated and the results were averaged.
【００３７】中心偏析度は、鋳片中心部より、直径５ｍ
ｍのドリル刃により穿孔して得られた切り削のＣ含有率
Ｃに対する鋳片のレードルＣ分析値Ｃ0 の比Ｃ／Ｃ0 に
より評価した。５個の横断面サンプルを調査して、その
結果を平均して求めた。The center segregation degree is 5 m in diameter from the center of the slab.
It was evaluated by the ratio C / C 0 of the ladle C analysis value C 0 of the cast slab to the C content C of the cut obtained by drilling with a m drill blade. Five cross-sectional samples were investigated and the results were averaged.
【００３８】内部割れは、５個の横断面サンプルのサル
ファプリントにより判定し、その割れ発生の程度を、な
し、軽微および顕著で評価した。Internal cracks were determined by sulfur printing of five cross-sectional samples, and the degree of occurrence of the cracks was evaluated as none, slight, or remarkable.
【００３９】さらに、鋳片の圧下中に鋳片の引き抜き作
業の状況について観察し、引き抜き不可が発生するかど
うかを評価した。Further, the state of the work of drawing the slab during the rolling of the slab was observed, and it was evaluated whether or not the drawing was impossible.
【００４０】これらの試験条件および試験結果を表１に
示す。Table 1 shows the test conditions and test results.
【００４１】[0041]
【表１】 [Table 1]
【００４２】本発明例の試験Ｎｏ．１〜Ｎｏ．５では、
本発明で規定する中心固相率の範囲内の０．３０〜０．
９０および本発明で規定する圧下形状比の範囲内の１．
６〜３．８の条件で圧下した。その結果、ポロシティ面
積率は０．０１〜０．０２％と小さく、内部割れの発生
もなく、中心偏析度は０．９８〜０．９９であり、良好
な内部品質の鋳片が得られた。また、引き抜き作業も順
調であった。Test No. of the present invention example. 1 to No. In 5,
0.30 to 0.1 within the range of the central solid fraction specified in the present invention.
90 within the range of the rolling shape ratio defined in the present invention.
The pressure was reduced under the conditions of 6 to 3.8. As a result, the porosity area ratio was as small as 0.01 to 0.02%, no internal cracks occurred, the center segregation degree was 0.98 to 0.99, and a slab of good internal quality was obtained. . The pulling out work was also successful.
【００４３】比較例の試験Ｎｏ．６では、圧下形状比を
本発明で規定する範囲下限未満の１．０、比較例の試験
Ｎｏ．８では、中心固相率を本発明で規定する範囲下限
未満の０．２０で試験した。試験Ｎｏ．６では、内部割
れが発生するとともに、ポロシティ面積率は１．５％と
大きく、中心偏析度も１．３１と高く、悪かった。ま
た、圧下時の圧下量および水平ロールの直径が小さすぎ
て、中心偏析やポロシティが発生した。試験Ｎｏ．８で
は、内部割れは発生しなかったが、ポロシティ面積率は
２．８％、中心偏析度は１．４で、さらに悪い結果であ
った。また、圧下開始時の中心固相率が小さすぎて、圧
下後に中心偏析やポロシティが発生した。Test No. of Comparative Example In Test No. 6, the rolling shape ratio was 1.0, which was less than the lower limit of the range specified in the present invention, and Test No. In No. 8, the central solid fraction was tested at 0.20 which was below the lower limit of the range specified in the present invention. Test No. In No. 6, internal cracks occurred, the porosity area ratio was as large as 1.5%, and the degree of center segregation was as high as 1.31, which was poor. In addition, the amount of reduction during the reduction and the diameter of the horizontal roll were too small, and center segregation and porosity occurred. Test No. In No. 8, no internal cracking occurred, but the porosity area ratio was 2.8% and the degree of center segregation was 1.4, which was an even worse result. In addition, the center solid phase ratio at the start of the reduction was too small, and center segregation and porosity occurred after the reduction.
【００４４】比較例の試験Ｎｏ．７およびＮｏ．９で
は、圧下形状比または中心固相率を、本発明で規定する
範囲外の大きな値で試験しようとしたが、いずれも鋳片
の引き抜き作業ができず、鋳造試験ができなかった。Test No. of Comparative Example 7 and No. 7 In No. 9, an attempt was made to test the rolling shape ratio or the central solid phase ratio at a large value outside the range specified in the present invention, but none of them could perform the work of pulling out the slab and could not perform the casting test.
【００４５】[0045]
【発明の効果】本発明の方法の適用により、中心偏析お
よびセンターポロシティがなく、かつ内部割れの発生も
ない、内部品質に優れたビームブランクを製造すること
が可能である。さらに、製造コストの削減が可能であ
る。According to the method of the present invention, it is possible to produce a beam blank having excellent center quality without center segregation and center porosity and without occurrence of internal cracks. Further, manufacturing costs can be reduced.
【図１】本発明の方法を実施するための連続鋳造装置の
構成を示す図である。FIG. 1 is a diagram showing a configuration of a continuous casting apparatus for performing a method of the present invention.
【図２】断面形状が矩形の鋳片を未凝固圧下したときの
鋳片の横断面形状を模式的に示す図である。FIG. 2 is a view schematically showing a cross-sectional shape of a slab when a slab having a rectangular cross-sectional shape is unsolidified and reduced.
【図３】センターポロシティの最大径に及ぼす圧下形状
比αの影響を示す図である。FIG. 3 is a diagram showing the effect of the rolling shape ratio α on the maximum diameter of the center porosity.
【図４】内部割れ最大長さに及ぼす圧下形状比αの影響
を示す図である。FIG. 4 is a diagram showing the influence of the rolling shape ratio α on the maximum length of internal cracks.
１： 鋳片 ２−１、２−２： 水平ロール ３−１、３−２： 垂直ロール ４： 鋳型 ５： 二次冷却帯 ６： ガイドロール ７： ピンチロール ８： 未凝固部 ９： 未凝固圧下装置 １０： ビームブランク 1: Slabs 2-1 and 2-2: Horizontal rolls 3-1 and 3-2: Vertical rolls 4: Mold 5: Secondary cooling zone 6: Guide rolls 7: Pinch rolls 8: Unsolidified parts 9: Unsolidified parts Reduction device 10: Beam blank
フロントページの続き (56)参考文献 特開 平８−281301（ＪＰ，Ａ) 特開 昭58−29548（ＪＰ，Ａ) 特開 平６−126406（ＪＰ，Ａ) 特開 平10−193064（ＪＰ，Ａ) 特開2000−15398（ＪＰ，Ａ) 特開 平11−156512（ＪＰ，Ａ) 特開 平11−129060（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) B22D 11/00 B22D 11/128 350 B22D 11/20 Continuation of front page (56) References JP-A-8-281301 (JP, A) JP-A-58-29548 (JP, A) JP-A-6-126406 (JP, A) JP-A-10-193064 (JP) JP-A-2000-15398 (JP, A) JP-A-11-156512 (JP, A) JP-A-11-129060 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name ) B22D 11/00 B22D 11/128 350 B22D 11/20
Claims (1)
を備える少なくとも１台の圧下装置を用いて、内部に未
凝固部が存在する断面形状が矩形の鋳片を、上下および
左右方向から圧下することによりビームブランクを製造
する方法において、圧下開始時期を圧下位置における鋳
片の中心固相率が０．３以上０．９８未満の間とし、下
記（Ａ）式で表される圧下形状比αが１．２以上５．８
以下となる条件で圧下することを特徴とするビームブラ
ンクの連続鋳造方法。 α ＝ （Ｄ・Ｒ）0.5／Ｌ ・・・（Ａ） ここで、Ｄ：水平ロールの直径（ｍｍ） Ｒ：水平ロールによる鋳片の圧下量（ｍｍ） Ｌ：圧下位置における鋳片内の固相率０．９９の凝固界
面間の圧下方向の未凝固部の厚み（ｍｍ）1. A slab having a rectangular cross-sectional shape having an unsolidified portion therein is reduced from above and below and from side to side by using at least one reduction device having a pair of horizontal rolls and a pair of vertical rolls. In the method for manufacturing a beam blank, the rolling start timing is set so that the center solid phase ratio of the slab at the rolling position is 0.3 or more and less than 0.98, and the rolling shape ratio α represented by the following formula (A): Is 1.2 or more and 5.8
A continuous casting method of a beam blank, wherein the reduction is performed under the following conditions. α = (D · R) 0.5 / L (A) where, D: diameter of horizontal roll (mm) R: amount of reduction of slab by horizontal roll (mm) L: in slab at reduction position The thickness (mm) of the unsolidified portion in the rolling direction between solidification interfaces with a solid phase ratio of 0.99
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32624898A JP3356084B2 (en) | 1998-11-17 | 1998-11-17 | Continuous casting method of beam blank |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32624898A JP3356084B2 (en) | 1998-11-17 | 1998-11-17 | Continuous casting method of beam blank |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2000153342A JP2000153342A (en) | 2000-06-06 |
| JP3356084B2 true JP3356084B2 (en) | 2002-12-09 |
Family
ID=18185659
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP32624898A Expired - Fee Related JP3356084B2 (en) | 1998-11-17 | 1998-11-17 | Continuous casting method of beam blank |
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| Country | Link |
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Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5829548A (en) * | 1981-08-18 | 1983-02-21 | Nippon Steel Corp | Continuous casting device for steel |
| JP2995520B2 (en) * | 1992-10-20 | 1999-12-27 | 新日本製鐵株式会社 | How to improve the quality of continuous cast slabs |
| JPH08281301A (en) * | 1995-04-14 | 1996-10-29 | Nippon Steel Corp | Production of beam blank |
| JP3139402B2 (en) * | 1997-01-10 | 2001-02-26 | 住友金属工業株式会社 | Unsolidified rolling method of slab |
| JP3240978B2 (en) * | 1997-10-28 | 2001-12-25 | 住友金属工業株式会社 | Manufacturing method of continuous cast slab |
| JPH11156512A (en) * | 1997-12-02 | 1999-06-15 | Sumitomo Metal Ind Ltd | Unsolidified press down manufacturing method of blank beam |
| JP2000015398A (en) * | 1998-06-29 | 2000-01-18 | Sumitomo Metal Ind Ltd | Method for continuously casting beam blank |
-
1998
- 1998-11-17 JP JP32624898A patent/JP3356084B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP2000153342A (en) | 2000-06-06 |
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