JP2009248178A - Vibration method for continuous casting mold for steel and continuous casting method for steel - Google Patents
Vibration method for continuous casting mold for steel and continuous casting method for steel Download PDFInfo
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本発明は、鋼の連続鋳造鋳型の振動方法及び鋼の連続鋳造方法に関する。 The present invention relates to a vibration method of a continuous casting mold of steel and a continuous casting method of steel.
鋼の連続鋳造では、鋳型と鋳片間の潤滑が不十分となると凝固シェルが鋳型に焼き付き、凝固シェルが破断を繰り返し、拘束性ブレークアウトが発生する。これを防止するため、鋳型は上下方向に振動（オシレーション）する機構を持っている。加えて、鋳型内には連続鋳造用パウダーが添加される。連続鋳造用パウダーはＣａＯ、ＳｉＯ2、Ｎａ2Ｏ、Ｆを主成分とする合成スラグであり、鋳型内の溶鋼表面で溶融し、鋳型壁と凝固シェルの間に流入し、鋳型と鋳片間の潤滑剤として働く。このように、鋼の連続鋳造においては、鋳型振動の付与と連続鋳造用パウダーの添加により、鋳型と鋳片間の潤滑が確保されている。 In continuous casting of steel, if the lubrication between the mold and the slab becomes insufficient, the solidified shell will seize on the mold, the solidified shell will repeatedly break, and a restrictive breakout will occur. In order to prevent this, the mold has a mechanism that vibrates in the vertical direction (oscillation). In addition, continuous casting powder is added into the mold. Continuous casting powder is a synthetic slag composed mainly of CaO, SiO 2 , Na 2 O, and F. It melts on the molten steel surface in the mold and flows between the mold wall and the solidified shell. Works as a lubricant. Thus, in continuous casting of steel, lubrication between the mold and the slab is ensured by applying mold vibration and adding powder for continuous casting.
このうち鋳型振動法では、通常は正弦波の振動が与えられる。また鋳型振動の１周期において、鋳型の下降速度が鋳造速度を上回る時間すなわちネガティブストリップタイムの確保が必要である。このネガティブストリップタイムには、凝固シェルに鋳造方向の圧縮力が加わるために、それ以外の時期（これをポジティブストリップタイムと呼ぶ）に加わった引張力を緩和する作用がある。特許文献１にはネガティブストリップタイムを０．１−０．２秒の範囲に制御することを特徴とする鋳造方法について記述されている。 Of these, the mold vibration method usually gives a sinusoidal vibration. Also, it is necessary to secure a time during which the mold lowering speed exceeds the casting speed, that is, a negative strip time, in one cycle of the mold vibration. The negative strip time has a function of relaxing the tensile force applied at other times (referred to as positive strip time) because a compressive force in the casting direction is applied to the solidified shell. Patent Document 1 describes a casting method characterized in that the negative strip time is controlled within a range of 0.1 to 0.2 seconds.
また連続鋳造パウダーによる鋳型内潤滑の指標としてパウダーの消費量が用いられている。パウダー消費量が少なくパウダーの流入が不十分となると、ブレークアウトが発生しやすい。パウダー消費量は、パウダーの粘度、凝固温度の低減により増加するため、このような物性のパウダーではブレークアウトは生じにくい。しかし、パウダー粘度が低いとパウダーが溶鋼中に巻き込まれて鋳片の欠陥となる。また凝固温度が低いパウダーを用いると、鋳型・鋳片間におけるパウダーの固着層の形成が不十分となり、鋳型内抜熱量が増加するので、鋳片表面の縦割れが生じやすい。 In addition, powder consumption is used as an index of in-mold lubrication by continuous casting powder. Breakout is likely to occur when powder consumption is low and powder inflow is insufficient. Since powder consumption increases due to reduction of powder viscosity and coagulation temperature, breakout is unlikely to occur with powders having such physical properties. However, when the powder viscosity is low, the powder is caught in the molten steel and becomes a defect of the slab. If a powder having a low solidification temperature is used, the formation of a fixed layer of the powder between the mold and the slab becomes insufficient, and the amount of heat extracted from the mold increases, so that the slab surface tends to crack vertically.
またパウダー消費量は、鋳型振動の振動数の低減により、増加することが知られている。ただし、振動数を下げると鋳型下降速度が小さくなるため、ネガティブストリップタイムの確保が困難になり、必ずしも鋳型内潤滑の改善にはつながらない。 Further, it is known that the powder consumption is increased by reducing the frequency of the mold vibration. However, if the frequency is lowered, the mold lowering speed becomes smaller, so that it becomes difficult to ensure the negative strip time, and this does not necessarily lead to improvement of the lubrication within the mold.
加えて正弦波以外の振動波形についての提案も見られる。特許文献２では、鋳型が上昇する時間を下降する時間より長くすることを特徴とする鋳型の振動方法が提案されている。非特許文献１には、この技術によりオシレーションマークが浅くなることが報告されている。またパウダー消費量も若干増加することが報告されている。しかしオシレーションマークが浅く不安定に形成されることは、パウダー流入も不安定にすると思われ、パウダー消費量を増加できても鋳型内潤滑の抜本的な改善には結びつかないと考えられる。 In addition, there are proposals for vibration waveforms other than sine waves. Patent Document 2 proposes a mold vibration method characterized in that the time during which the mold rises is longer than the time during which the mold rises. Non-Patent Document 1 reports that this technique makes the oscillation mark shallower. It has also been reported that powder consumption increases slightly. However, when the oscillation mark is shallow and unstable, it is thought that the powder inflow is also unstable, and even if the powder consumption can be increased, it is considered that it does not lead to a drastic improvement in the lubrication in the mold.
以上のように、鋼の連続鋳造では鋳型振動と連続鋳造用パウダーにより、鋳型と鋳片間の潤滑がなされる。しかしながら、さらなる高速鋳造のために潤滑を向上させたり、パウダーの巻き込みを防止するために粘度の高いパウダーを使用したりするためには、さらなるパウダー流入の安定化が必要であり、これが本発明における課題である。 As described above, in continuous casting of steel, the mold and the slab are lubricated by the mold vibration and the powder for continuous casting. However, in order to improve lubrication for further high-speed casting and to use powder with high viscosity to prevent entrainment of powder, further stabilization of powder inflow is necessary, which is the present invention. It is a problem.
本発明者らは、鋳型振動によるパウダーの流入メカニズムに関して詳細な解析を行い、以下の点を明らかにした。 The present inventors conducted detailed analysis on the inflow mechanism of powder by mold vibration, and clarified the following points.
鋳型と鋳片間のパウダー流入は、おもに鋳型振動と鋳片の引き抜きによるパウダーの引きずりによって流入する。この際に下方にどれだけのパウダーが流入するかは、パウダーの流路の厚みに大きく依存する。この流路の厚みは、パウダー流路内の圧力と凝固シェルに働く溶鋼静圧のバランスによって決定される。このうちパウダー流路内の圧力は、鋳型振動に伴う動圧の変化によって変化する。そのためオシレーションによって流路の厚みが変化を繰り返すことになる。すなわち、鋳型上昇期には流路内の圧力が上昇し流路が拡大し、鋳型下降時には流路内の圧力が低下し流路が縮小する。ただし鋳型上昇時には鋳型の上昇に引きずられてパウダーは上方に逆流し、鋳型下降時には下向きに流入する。以上を総括すると、鋳型上昇によって拡大されたパウダーの流路に、鋳型下降時にパウダーが引きずり込まれ、パウダーが流入する。 The powder inflow between the mold and the slab mainly flows in due to the vibration of the mold and dragging of the powder due to the slab pulling out. At this time, how much powder flows downward depends greatly on the thickness of the powder passage. The thickness of this flow path is determined by the balance between the pressure in the powder flow path and the molten steel static pressure acting on the solidified shell. Among these, the pressure in the powder flow path changes due to a change in dynamic pressure accompanying mold vibration. Therefore, the thickness of the flow path is repeatedly changed by the oscillation. That is, the pressure in the flow path increases and the flow path expands during the mold rising period, and the pressure in the flow path decreases and the flow path shrinks when the mold descends. However, when the mold is raised, the powder is dragged upward by the mold, and the powder flows back upward. When the mold is lowered, the powder flows downward. In summary, the powder is dragged into the powder flow path enlarged by the mold rising, and the powder flows in when the mold is lowered.
また鋳型オシレーションにより鋳片の表面にはオシレーションマーク、すなわち周期的な凹凸が形成される。オシレーションマークは鋳型湯面での曲率をもったメニスカス部で凝固シェルが形成されるために生じるが、メニスカス部での凝固シェルはパウダーを引きずり込む作用を持つことがわかった。したがって、オシレーションマークが安定的に形成されると、パウダーの流入は増加する。 Moreover, an oscillation mark, that is, periodic irregularities are formed on the surface of the slab by mold oscillation. Oscillation marks occur because a solidified shell is formed at the meniscus portion having a curvature on the mold surface, but it has been found that the solidified shell at the meniscus portion has an action of dragging powder. Therefore, when the oscillation mark is stably formed, the inflow of powder increases.
このような知見を踏まえ本発明者らは、さらに効果的にパウダーを流入させる鋳型振動波形の検討を行った。その結果、通常の正弦波の振動と異なり、鋳型上昇時間が鋳型下降時間に比べて短い振動波形の方が、流路の拡大している時間が長く、パウダーの流入が促進されることがわかった。この効果は、凝固シェルに働く慣性力の作用により、鋳型下降時にも流路が開いた状態が長く継続されるためである。またこのような波形を用いると、鋳片表面のオシレーションマークがより周期的かつ安定的に形成されることが分かった。このことも、パウダー流入の安定化に寄与する。 Based on such knowledge, the present inventors have studied a mold vibration waveform for allowing powder to flow more effectively. As a result, unlike the normal sine wave vibration, it was found that the vibration waveform with a shorter mold rise time compared to the mold fall time has a longer flow path expansion time and promotes the inflow of powder. It was. This effect is due to the action of the inertial force acting on the solidified shell, which keeps the channel open for a long time even when the mold is lowered. It was also found that when such a waveform was used, the oscillation mark on the slab surface was formed more periodically and stably. This also contributes to stabilization of powder inflow.
本発明は上記知見に基づいてなされたものであり、その要旨とするところは以下のとおりである。
（１）鋳型を上下方向に振動させる鋼の連続鋳造鋳型の振動方法において、次式で定義される鋳型上昇時間率τが０．３４以上０．５未満であることを特徴とする鋼の連続鋳造鋳型の振動方法。
τ＝（振動１周期における鋳型上昇時間）／（振動１周期）
（２）鋳型振動のストロークが３ｍｍ以上１０ｍｍ以下であることを特徴とする上記（１）に記載の鋼の連続鋳造鋳型の振動方法。
（３）鋳型降下速度が鋳造速度を上回る時間が、振動１周期内で０．１秒以上であることを特徴とする上記（１）又は（２）に記載の鋼の連続鋳造鋳型の振動方法。
（４）上記（１）乃至（３）のいずれかに記載の鋼の連続鋳造鋳型の振動方法を用いた鋼の連続鋳造方法であって、１３００℃における粘性が８ｐｏｉｓｅ以上の連続鋳造パウダーを用いて鋳造することを特徴とする鋼の連続鋳造方法。
（５）上記（１）乃至（３）のいずれかに記載の鋼の連続鋳造鋳型の振動方法を用いた鋼の連続鋳造方法であって、鋳造速度２．０ｍ／ｍｉｎ以上で鋳造することを特徴とする鋼の連続鋳造方法。
This invention is made | formed based on the said knowledge, The place made into the summary is as follows.
(1) In a steel continuous casting mold vibration method in which the mold is vibrated in the vertical direction, the mold rising time rate τ defined by the following formula is 0.34 or more and less than 0.5, and the continuous steel Casting mold vibration method.
τ = (mold rise time in one vibration period) / (one vibration period)
(2) The method for vibrating a continuous casting mold for steel as set forth in (1) above, wherein the stroke of the mold vibration is 3 mm or more and 10 mm or less.
(3) The method for vibrating a continuous casting mold for steel according to (1) or (2) above, wherein the time during which the mold lowering speed exceeds the casting speed is 0.1 second or more within one vibration period .
(4) A continuous casting method of steel using the vibration method of the continuous casting mold for steel according to any one of (1) to (3) above, wherein a continuous casting powder having a viscosity at 1300 ° C. of 8 poise or more is used. A continuous casting method of steel characterized by casting.
(5) A continuous casting method of steel using the vibration method of the continuous casting mold for steel according to any one of (1) to (3) above, wherein casting is performed at a casting speed of 2.0 m / min or more. A method for continuous casting of steel.
本発明により、鋳型・凝固シェル間への連続鋳造用パウダーの流入を促進し、鋳型内の潤滑を安定化することができる。その結果として、従来にない高速鋳造の実現や高粘性パウダーを用いた操業が可能となった。 According to the present invention, the inflow of the powder for continuous casting between the mold and the solidified shell can be promoted, and the lubrication in the mold can be stabilized. As a result, unprecedented high-speed casting and operation using high-viscosity powder became possible.
本発明で用いる鋳型の振動波形は、通常、油圧シリンダー方式の鋳型振動装置によって得られる。油圧ステッピングシリンダー、電気油圧式アクチュエータなどを用いることができる。 The vibration waveform of the mold used in the present invention is usually obtained by a hydraulic cylinder type mold vibration apparatus. A hydraulic stepping cylinder, an electrohydraulic actuator, or the like can be used.
本発明では、図４に示すように、［振動１周期における鋳型上昇時間］Ｂと［振動１周期］Ａに基づき、鋳型上昇時間率τを次式によって定義する。
τ＝Ｂ／Ａ＝（振動１周期における鋳型上昇時間）／（振動１周期）
In the present invention, as shown in FIG. 4, the mold rising time rate τ is defined by the following equation based on [Mold rising time in one vibration period] B and [One vibration period] A.
τ = B / A = (Template rising time in one vibration period) / (One vibration period)
本発明において、鋳型上昇時間率τは０．３４以上０．５未満とする。０．４７以下であると好ましい。前述のように、鋳型上昇時間が鋳型下降時間に比べて短い振動波形の方が、すなわち鋳型上昇時間率τが低いほどパウダー消費量が増加する。したがって、パウダー消費量の確保という点では鋳型上昇時間率τは低いほどよい。ただし、鋳型上昇時間率τが著しく低いと、鋳型上昇時の上昇速度と鋳片下降速度（すなわち鋳造速度）との相対速度が著しく大きくなり、凝固シェルの破断をもたらす場合がある。したがって、鋳型上昇時間率τは０．３４以上が好ましく、さらに好ましくは０．３８以上である。これに対して、鋳型上昇時間率τが０．５に近づくと、すなわち鋳造の正弦波の振動に近づくと、パウダー消費量は低下する。すなわち本発明の効果は得られにくくなる。またオシレーションマークの形成も浅く、不安定になりやすい。したがって、鋳型上昇時間率τは０．５未満、好ましくは０．４７以下、さらに好ましくは０．４５以下である。鋳型上昇時間率τが０．５以上である従来の連続鋳造においては、パウダーの粘度が高いほど、パウダー消費量が少なくなる傾向が顕著となっていた。それに対し本発明においては、鋳型上昇時間率τを０．５未満とすることにより、パウダー消費量が増加するとともにパウダー粘度によるパウダー消費量の変化が少なくなるという効果を得ることができる。そのため、１３００℃における粘性が８ｐｏｉｓｅ以上の連続鋳造パウダーを用いてもパウダー消費量を確保することが可能となる。 In the present invention, the mold rising time rate τ is 0.34 or more and less than 0.5. It is preferable that it is 0.47 or less. As described above, the amount of powder consumption increases as the vibration waveform has a shorter mold rise time than the mold fall time, that is, as the mold rise time rate τ is lower. Therefore, the lower the mold rising time rate τ is better in terms of securing the powder consumption. However, when the mold rising time rate τ is extremely low, the relative speed between the rising speed when the mold is raised and the slab lowering speed (that is, the casting speed) is remarkably increased, and the solidified shell may be broken. Therefore, the mold rising time rate τ is preferably 0.34 or more, more preferably 0.38 or more. On the other hand, when the mold rising time rate τ approaches 0.5, that is, when it approaches the vibration of a casting sine wave, the powder consumption decreases. That is, the effect of the present invention is difficult to obtain. Also, the formation of oscillation marks is shallow and tends to be unstable. Therefore, the mold rising time rate τ is less than 0.5, preferably 0.47 or less, more preferably 0.45 or less. In the conventional continuous casting in which the mold rising time rate τ is 0.5 or more, the tendency that the powder consumption decreases as the viscosity of the powder increases. On the other hand, in the present invention, by setting the mold rising time rate τ to less than 0.5, it is possible to obtain the effect of increasing the powder consumption and reducing the change in the powder consumption due to the powder viscosity. Therefore, it is possible to ensure the amount of powder consumption even when using a continuously cast powder having a viscosity at 1300 ° C. of 8 poise or more.
次に、鋳型振動のストロークすなわち鋳型の最大の変位量は３ｍｍ以上１０ｍｍ以下が好ましく、さらに好ましくは５ｍｍ以上８ｍｍ以下である。鋳型振動ストロークが３ｍｍに満たないとオシレーションマークの形成が非常に小さく、パウダーの流入量が低下する。またストロークが１０ｍｍを超えると、鋳片表面にオシレーションマークが深く形成されるが、特に大きな鋳型振動によって溶鋼湯面の攪乱が起こるため、乱れたオシレーションマークが形成される。すなわち、オシレーションマークのピッチが非周期的となり、部分的に深いオシレーションマークが形成される。その結果、オシレーションマークの凹みに割れが生じたり、オシレーションマークの爪状の組織に気泡や介在物が捕捉されたりするため、鋳片品質が悪化する。 Next, the stroke of the mold vibration, that is, the maximum amount of displacement of the mold is preferably 3 mm or more and 10 mm or less, and more preferably 5 mm or more and 8 mm or less. If the mold vibration stroke is less than 3 mm, the formation of oscillation marks is very small and the amount of powder inflow is reduced. When the stroke exceeds 10 mm, an oscillation mark is formed deeply on the surface of the slab. However, since the molten steel surface is disturbed particularly by a large mold vibration, a distorted oscillation mark is formed. That is, the pitch of the oscillation mark becomes aperiodic and a partially deep oscillation mark is formed. As a result, cracks occur in the recesses of the oscillation mark, and bubbles and inclusions are trapped in the nail-like structure of the oscillation mark, so that the slab quality is deteriorated.
最後に鋳型振動の振動数は、ネガティブストリップが確保できるように設定すると好ましい。このためには、鋳造速度が速いほど、またストロークが小さいほど、大きな振動数を設定することが好ましい。また０．１秒以上のネガティブストリップタイムを設けることが望ましい。本発明においては、鋳型上昇時間率τを０．３４以上０．５未満とすることによりパウダー消費量の増加を実現するとともに、ネガティブストリップタイムを０．１秒以上とすることによって、ブレークアウト発生の原因となるブリード発生率を低減することができる。 Finally, the frequency of the mold vibration is preferably set so that a negative strip can be secured. For this purpose, it is preferable to set a larger frequency as the casting speed is higher and the stroke is smaller. It is desirable to provide a negative strip time of 0.1 seconds or more. In the present invention, the powder consumption is increased by setting the mold rising time rate τ to 0.34 or more and less than 0.5, and the breakout occurs by setting the negative strip time to 0.1 seconds or more. It is possible to reduce the occurrence rate of bleed that causes the above.
上記本発明の振動方法を用いた鋼の連続鋳造においては、パウダー消費量が増加し、特に粘度が高いパウダーにおいてパウダー消費量の増加が顕著である。従来、１３００℃における粘性が８ｐｏｉｓｅ以上の連続鋳造パウダーを用いるとパウダー消費量が不足して安定した鋳造が困難であった。それに対し、上記本発明の鋼の連続鋳造鋳型の振動方法を用いた鋼の連続鋳造方法においては、１３００℃における粘性が８ｐｏｉｓｅ以上の連続鋳造パウダーを用いて安定した連続鋳造が可能となった。これにより、鋳型内の凝固シェルへのパウダー巻き込みを低減して良好な品質の鋳片を安定して鋳造することが可能となる。 In the continuous casting of steel using the vibration method of the present invention, the amount of powder consumption increases, and the increase in the amount of powder consumption is particularly remarkable in powders with high viscosity. Conventionally, when a continuous casting powder having a viscosity at 1300 ° C. of 8 poise or more is used, powder consumption is insufficient and stable casting is difficult. On the other hand, in the continuous casting method of steel using the vibration method of the continuous casting mold of steel of the present invention, stable continuous casting is possible using continuous casting powder having a viscosity at 1300 ° C. of 8 poise or more. This makes it possible to stably cast a slab of good quality by reducing powder entrainment in the solidified shell in the mold.
従来、鋳造速度を２．０ｍ／ｍｉｎ以上の高速鋳造を行おうとすると、パウダー消費量が減少して安定した鋳造が困難であった。それに対し、本発明の鋼の連続鋳造鋳型の振動方法を用いた鋼の連続鋳造方法においては、鋳造速度２．０ｍ／ｍｉｎ以上で安定した鋳造することが可能となった。これにより、高い生産性を確保しつつ安定して鋳造することが可能となる。 Conventionally, when trying to perform high speed casting at a casting speed of 2.0 m / min or more, powder consumption is reduced and stable casting is difficult. On the other hand, in the continuous casting method of steel using the vibration method of the continuous casting mold of steel of the present invention, it has become possible to perform stable casting at a casting speed of 2.0 m / min or more. Thereby, it is possible to stably perform casting while ensuring high productivity.
次に本発明の実施例について述べる。 Next, examples of the present invention will be described.
低炭素アルミキルド鋼を転炉、二次精錬設備にて溶製し、垂直曲げ型のスラブ連続鋳造機で鋳造した。鋳片の断面サイズは２５０ｍｍ厚×２１００ｍｍ幅であった。鋳型に添加したパウダーの質量から鋳造中のパウダー消費量を算出した。また鋳型に埋設した熱電対により、拘束性ブレークアウトの検知を行い、検知率を評価した。 Low carbon aluminum killed steel was melted in a converter and secondary refining equipment, and cast with a vertical bending slab continuous casting machine. The cross-sectional size of the slab was 250 mm thick × 2100 mm wide. The powder consumption during casting was calculated from the mass of the powder added to the mold. In addition, restraint breakout was detected by a thermocouple embedded in the mold, and the detection rate was evaluated.
（実施例１）
連続鋳造において鋳型上昇時間率τを変化させ、パウダー消費量、オシレーションマーク深さ、ブレークアウト検知率に及ぼす影響を評価した。鋳型振動の鋳型振動数を１５５ｃｐｍ、振動ストロークを６．８ｍｍとし、図４に示すにように、鋳型上昇時と下降時にそれぞれ異なった周期の正弦波形とすることにより、鋳型上昇時間率τを調整した。連続鋳造用パウダーとして、１３００℃の粘度が１ｐｏｉｓｅ、４ｐｏｉｓｅ、８ｐｏｉｓｅの３種類の粘度のパウダーを用いた。鋳造速度を１．４ｍ／ｍｉｎとした。
Example 1
In continuous casting, the mold rising time rate τ was changed, and the effects on powder consumption, oscillation mark depth, and breakout detection rate were evaluated. The mold rising time rate τ is adjusted by setting the mold frequency of the mold vibration to 155 cpm, the vibration stroke to 6.8 mm, and sine waveforms with different periods when the mold is raised and lowered, as shown in FIG. did. As continuous casting powders, powders having a viscosity of 1300 ° C. and three types of viscosity of 1 poise, 4 poise, and 8 poise were used. The casting speed was 1.4 m / min.
図１に、鋳型上昇時間率τとパウダーの消費量の関係を示す。鋳型上昇時間率τが減少するにつれて、パウダー消費量は増加している。これはすでに述べたように、鋳型・鋳片間のパウダー流路が拡大している時間が長くなるためであると考えられる。さらに図２に鋳型上昇時間率τとオシレーションマーク深さの関係を示す。図２において、「●」が平均値、「−」が平均値から標準偏差だけ離れた位置を示している。図２から明らかなように、鋳型上昇時間率τの減少とともに、オシレーションマークが均一にすなわち安定的に生成している。このこともパウダー消費量の増加に寄与していると考えられる。 FIG. 1 shows the relationship between the mold rising time rate τ and the amount of powder consumed. As the mold rise time rate τ decreases, the powder consumption increases. As described above, this is considered to be because the time during which the powder flow path between the mold and the slab is expanded becomes longer. Further, FIG. 2 shows the relationship between the mold rising time rate τ and the oscillation mark depth. In FIG. 2, “●” indicates an average value, and “−” indicates a position away from the average value by a standard deviation. As is apparent from FIG. 2, the oscillation mark is uniformly or stably generated as the mold rising time rate τ decreases. This is also thought to contribute to an increase in powder consumption.
鋳型上昇時間率τが０．５以上では図２に示すようにオシレーションマークの形成が浅く不安定となり、図１に示すようにパウダー消費量が低下する。これに対して本発明のように、鋳型上昇時間率τが０．５よりも低くなると、図２のようにオシレーションマークが安定的に形成され、図１のようにパウダー消費量も増加する。さらに、鋳型上昇時間率τが０．４７以下であればパウダー消費量は十分に高位であり（図１）、図３に示すようにブレークアウトの検知率を低くできる。加えて鋳型上昇時間率τが０．３４以上であれば、鋳型上昇時における鋳片と鋳型との相対速度が大きすぎないため、鋳片に働く引張応力が小さい。そのため、図３に示すようにブレークアウトの検知率が低い。 When the mold rising time rate τ is 0.5 or more, the formation of the oscillation mark is shallow and unstable as shown in FIG. 2, and the powder consumption is reduced as shown in FIG. On the other hand, when the mold rising time rate τ is lower than 0.5 as in the present invention, the oscillation mark is stably formed as shown in FIG. 2, and the powder consumption is also increased as shown in FIG. . Furthermore, if the mold rising time rate τ is 0.47 or less, the powder consumption is sufficiently high (FIG. 1), and the breakout detection rate can be lowered as shown in FIG. In addition, if the mold rising time rate τ is 0.34 or more, the tensile stress acting on the slab is small because the relative speed between the slab and the mold when the mold is rising is not too high. Therefore, the breakout detection rate is low as shown in FIG.
このように鋳造速度、鋳型振幅、振動数、モールドパウダーの粘性が同じ場合において、鋳型上昇時間率τが本発明範囲に入る場合には、鋳型上昇時間率τが本発明範囲から外れる場合に比べてパウダー消費量が増加している。そのためブレークアウト検知率が低位である。 As described above, when the casting speed, mold amplitude, frequency, and mold powder viscosity are the same, when the mold rising time rate τ falls within the range of the present invention, the mold rising time rate τ deviates from the range of the present invention. As a result, powder consumption is increasing. Therefore, the breakout detection rate is low.
図１において、連続鋳造用パウダーの１３００℃の粘度が１ｐｏｉｓｅ、４ｐｏｉｓｅ、８ｐｏｉｓｅの３種類の粘度のパウダーを用いた。図１から明らかなように、鋳型上昇時間率τが０．５以上の従来の領域においては、パウダーの粘度が高くなるほどパウダー消費量が低下していることがわかる。それに対し、鋳型上昇時間率τが０．５未満の本発明範囲では、パウダーの粘度が高くなってもパウダー消費量がさほど低下しないことが明らかである。鋳型上昇時間率が低くなるほどこの傾向は顕著である。すなわち、本発明では、特にパウダーの粘度が高い場合でも図１に示すようにパウダー消費量は大きく低下しない。よってパウダー消費量の粘度依存性が小さいため、粘度の高いパウダーを使用することが可能である。 In FIG. 1, powders having a viscosity of 1300 ° C. and three types of viscosity of 1 poise, 4 poise, and 8 poise were used as the powder for continuous casting. As can be seen from FIG. 1, in the conventional region where the mold rising time rate τ is 0.5 or more, the powder consumption decreases as the powder viscosity increases. On the other hand, in the range of the present invention where the mold rising time rate τ is less than 0.5, it is apparent that the powder consumption does not decrease so much even if the powder viscosity increases. This tendency becomes more prominent as the mold rising time rate becomes lower. That is, in the present invention, even when the viscosity of the powder is particularly high, the powder consumption is not greatly reduced as shown in FIG. Therefore, since the viscosity dependence of the powder consumption is small, it is possible to use a powder having a high viscosity.
（実施例２）
連続鋳造において、鋳型上昇時間率τ、鋳型振動の振動数、振動ストローク、鋳造速度を変化させ、また使用する連続鋳造用パウダーの粘度を変化させ、ネガティブストリップタイムＴN、パウダー消費量の評価を行った。図４に示すにように、鋳型上昇時と下降時にそれぞれ異なった周期の正弦波形とすることにより、鋳型上昇時間率τを調整した。結果を表１に示す。実施例１〜８８が本発明例、比較例１〜２７が比較例である。
(Example 2)
In continuous casting, change the mold rising time rate τ, mold vibration frequency, vibration stroke, casting speed, change the viscosity of the powder for continuous casting used, and evaluate the negative strip time T N and the powder consumption. went. As shown in FIG. 4, the mold rising time rate τ was adjusted by using a sinusoidal waveform with different periods when the mold was raised and lowered. The results are shown in Table 1. Examples 1 to 88 are examples of the present invention, and Comparative Examples 1 to 27 are comparative examples.
表１の実施例１〜４を対比すると、本発明範囲内で鋳型上昇時間率τを低くするほど、パウダー消費量が増加することがわかる。これに対し比較例１〜３は鋳型上昇時間率τが本発明範囲外であり、パウダー消費量が少ない。 Comparing Examples 1 to 4 in Table 1, it can be seen that the lower the mold rising time rate τ within the scope of the present invention, the higher the powder consumption. On the other hand, in Comparative Examples 1 to 3, the mold rising time rate τ is outside the range of the present invention, and the powder consumption is small.
表１の実施例１、５、９、比較例１、４、８を対比すると、本発明範囲内で鋳型上昇時間率τが低くなると、パウダーの粘度が高くなってもパウダー消費量の低下が小さいことがわかる。それに対し鋳型上昇時間率τが本発明範囲外となる比較例では、パウダーの粘度が高くなるとパウダー消費量が減少している。 When Examples 1, 5, 9 and Comparative Examples 1, 4, 8 in Table 1 are compared, if the mold rising time rate τ is low within the scope of the present invention, the powder consumption is reduced even if the powder viscosity is high. I understand that it is small. On the other hand, in the comparative example in which the mold rising time rate τ is out of the range of the present invention, the powder consumption decreases as the powder viscosity increases.
表１の実施例３７〜６０、比較例１５〜２０を対比すると、鋳造速度が２．５ｍ／ｍｉｎという高速鋳造においても、鋳型上昇時間率τが本発明範囲内であればパウダー消費量が十分に確保できることがわかる。高速鋳造下でもブレークアウトなく安定鋳造が可能である。それに対し鋳型上昇時間率τが本発明範囲外となる比較例では、高速鋳造において十分なパウダー消費量を確保することができない。なお、実施例３７〜４０において、ネガティブストリップタイムＴNが０．１秒以上のものは、０．１秒未満に比較してブレークアウト検知率がより一層低減している。 Comparing Examples 37 to 60 and Comparative Examples 15 to 20 in Table 1, even in a high speed casting at a casting speed of 2.5 m / min, the powder consumption is sufficient if the mold rising time rate τ is within the range of the present invention. It can be seen that it can be secured. Stable casting is possible without breakout even under high-speed casting. On the other hand, in the comparative example in which the mold rising time rate τ is outside the range of the present invention, it is not possible to ensure a sufficient powder consumption in high speed casting. In Examples 37 to 40, when the negative strip time TN is 0.1 seconds or more, the breakout detection rate is further reduced as compared to less than 0.1 seconds.
高速鋳造において、ネガティブストリップタイムＴNを０．１秒以上とするためには、鋳造速度に応じて、鋳型振動のストローク、振動数、鋳型上昇時間率τを調整することによって可能である。表１の実施例２６〜２８は鋳造速度２．０ｍ／ｍｉｎにおいて、実施例５１、５２などは鋳造速度２．５ｍ／ｎｉｎにおいて、ネガティブストリップタイムＴNが０．１秒以上となっている。 In high-speed casting, the negative strip time TN can be set to 0.1 seconds or more by adjusting the mold vibration stroke, frequency, and mold rising time rate τ according to the casting speed. Examples 26 to 28 in Table 1 have a negative strip time TN of 0.1 seconds or more at a casting speed of 2.0 m / min, and Examples 51 and 52 have a casting speed of 2.5 m / nin.
鋳型オシレーションのストロークが３ｍｍ以上の場合には、３ｍｍよりも小さい場合に比べて、パウダー消費量も大きくブリード検知率も少ない。表１の実施例８１〜８４（振動ストロークが２．８ｍｍ）とそれ以外の実施例を対比すると、振動ストロークが３ｍｍ以上である方がパウダー消費量がより一層増加していることがわかる。振動ストロークが１０ｍｍ以下である場合には、オシレーションマークの深さが適度であり、良好な表面状態の鋳片を得ることができる。一方、実施例７３〜７６は振動ストロークが１０．４ｍｍと大きく、鋳造した鋳片のオシレーションマークが深くなる傾向が見られた。鋳片品質の点では、振動ストロークを１０ｍｍ以下としてオシレーションマークを浅く保つことにより良好な品質を得ることができるので好ましい。 When the stroke of the mold oscillation is 3 mm or more, the powder consumption is large and the bleed detection rate is small as compared with the case where the stroke is smaller than 3 mm. When Examples 81 to 84 (vibration stroke is 2.8 mm) in Table 1 and the other examples are compared, it can be seen that the powder consumption is further increased when the vibration stroke is 3 mm or more. When the vibration stroke is 10 mm or less, the depth of the oscillation mark is appropriate, and a cast piece having a good surface state can be obtained. On the other hand, in Examples 73 to 76, the vibration stroke was as large as 10.4 mm, and there was a tendency that the oscillation mark of the cast slab became deep. In terms of slab quality, it is preferable to obtain a good quality by keeping the oscillation mark shallow by setting the vibration stroke to 10 mm or less.
Claims (5)
τ＝（振動１周期における鋳型上昇時間）／（振動１周期） In a method for vibrating a continuous casting mold of steel in which the mold is vibrated in the vertical direction, a mold rising time rate τ defined by the following formula is 0.34 or more and less than 0.5, Vibration method.
τ = (mold rise time in one vibration period) / (one vibration period)
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102717044A (en) * | 2011-03-29 | 2012-10-10 | 鞍钢股份有限公司 | Method for controlling nail shooting process of continuous casting slab |
| JP2012206160A (en) * | 2011-03-30 | 2012-10-25 | Nippon Steel Corp | Continuous casting method |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS606248A (en) * | 1983-06-27 | 1985-01-12 | Nippon Kokan Kk <Nkk> | Oscillating method of continuous casting mold |
| JPH04172161A (en) * | 1990-11-05 | 1992-06-19 | Nkk Corp | Method for continuously casting cast slab having beautiful surface |
| JPH08257695A (en) * | 1995-01-25 | 1996-10-08 | Nippon Steel Corp | Continuous casting mold for steel and continuous casting method |
| JPH105956A (en) * | 1996-06-27 | 1998-01-13 | Kawasaki Steel Corp | Continuous casting method of steel |
| JP2002153946A (en) * | 2000-11-21 | 2002-05-28 | Nkk Corp | Method for continuously casting extra-low carbon steel |
| JP2003094155A (en) * | 2001-09-21 | 2003-04-02 | Kawasaki Steel Corp | Continuous casting method for steel |
| JP2004122139A (en) * | 2002-09-30 | 2004-04-22 | Jfe Steel Kk | Method for continuously casting extra-low carbon steel and mold powder for continuous casting |
-
2008
- 2008-04-10 JP JP2008102549A patent/JP5130485B2/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS606248A (en) * | 1983-06-27 | 1985-01-12 | Nippon Kokan Kk <Nkk> | Oscillating method of continuous casting mold |
| JPH04172161A (en) * | 1990-11-05 | 1992-06-19 | Nkk Corp | Method for continuously casting cast slab having beautiful surface |
| JPH08257695A (en) * | 1995-01-25 | 1996-10-08 | Nippon Steel Corp | Continuous casting mold for steel and continuous casting method |
| JPH105956A (en) * | 1996-06-27 | 1998-01-13 | Kawasaki Steel Corp | Continuous casting method of steel |
| JP2002153946A (en) * | 2000-11-21 | 2002-05-28 | Nkk Corp | Method for continuously casting extra-low carbon steel |
| JP2003094155A (en) * | 2001-09-21 | 2003-04-02 | Kawasaki Steel Corp | Continuous casting method for steel |
| JP2004122139A (en) * | 2002-09-30 | 2004-04-22 | Jfe Steel Kk | Method for continuously casting extra-low carbon steel and mold powder for continuous casting |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102717044A (en) * | 2011-03-29 | 2012-10-10 | 鞍钢股份有限公司 | Method for controlling nail shooting process of continuous casting slab |
| CN102717044B (en) * | 2011-03-29 | 2014-09-03 | 鞍钢股份有限公司 | Method for controlling nail shooting process of continuous casting slab |
| JP2012206160A (en) * | 2011-03-30 | 2012-10-25 | Nippon Steel Corp | Continuous casting method |
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