TWI599417B - Continuous Casting of Steel Emboss Casting - Google Patents
Continuous Casting of Steel Emboss Casting Download PDFInfo
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- TWI599417B TWI599417B TW105130015A TW105130015A TWI599417B TW I599417 B TWI599417 B TW I599417B TW 105130015 A TW105130015 A TW 105130015A TW 105130015 A TW105130015 A TW 105130015A TW I599417 B TWI599417 B TW I599417B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
- B22D11/116—Refining the metal
- B22D11/117—Refining the metal by treating with gases
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/10—Supplying or treating molten metal
- B22D11/11—Treating the molten metal
- B22D11/114—Treating the molten metal by using agitating or vibrating means
- B22D11/115—Treating the molten metal by using agitating or vibrating means by using magnetic fields
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Description
本發明係關於:藉由控制鑄模內的熔鋼流來製造鋼胚鑄片表層內的非金屬夾雜物很少的高品質鋼胚鑄片之連續鑄造方法。 BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a continuous casting process for producing high quality steel slabs having few non-metallic inclusions in the surface layer of a steel slab by controlling the flow of molten steel in the mold.
近年來,汽車外板用鋼板、罐用鋼板之類的高級鋼製品的品質要求更嚴格,在鋼胚鑄片的階段,換言之,從連續鑄造階段就要求鋼胚鑄片的高品質化。鋼胚鑄片被要求的品質之一,例如:在鋼胚鑄片表層內的非金屬夾雜物(後述說明中,簡稱為「夾雜物」)很少。 In recent years, the quality requirements of high-grade steel products such as steel sheets for automobile outer panels and steel sheets for cans have been stricter, and in the stage of steel slab casting, in other words, high quality of steel slabs has been required from the continuous casting stage. One of the required qualities of the steel slab is, for example, a non-metallic inclusion in the surface layer of the steel slab (in the following description, simply referred to as "inclusion").
被捕捉於鋼胚鑄片的表層內的夾雜物,可例舉出下列的物質。 The inclusions trapped in the surface layer of the steel slab are exemplified by the following.
(a)藉由鋁之類的元素來進行熔鋼的脫氧工序時,所生成的懸浮在熔鋼中的脫氧生成物。 (a) A deoxidation product suspended in a molten steel when the molten steel deoxidation step is performed by an element such as aluminum.
(b)利用澆鑄槽、浸漬式噴嘴吹入到熔鋼內的氬氣的氣泡內部所包含的細微的氧化物。 (b) A fine oxide contained in the inside of the bubble of the argon gas blown into the molten steel by the casting tank or the immersion nozzle.
(c)添加在鑄模內的熔鋼湯面上的鑄模粉被捲入熔鋼中而形成的懸濁物等。 (c) A suspension or the like formed by the mold powder added to the molten steel soup surface in the mold being wound into the molten steel.
上述夾雜物都會在鋼製品的階段形成表面缺陷,因此,盡量地減少被鋼胚鑄片的表層所捕捉到的夾雜物的量是很重要。此外,如果被捕捉在鋼胚鑄片的表層的氬氣氣泡,在鋼胚鑄片表層破裂開的話,氣泡內部因受到加熱爐等的加熱而被氧化,氧化後的部分將會成為表面缺陷。 The above inclusions all form surface defects at the stage of the steel product, and therefore it is important to minimize the amount of inclusions caught by the surface layer of the steel slab. Further, if the argon gas bubbles caught in the surface layer of the steel slab are broken and the surface of the steel slab is broken, the inside of the bubble is oxidized by heating by a heating furnace or the like, and the oxidized portion becomes a surface defect.
以往,為了防止因為熔鋼中的脫氧生成物、氬氣氣泡、鑄模粉被凝固鑄片外殼所捕捉而成為鋼製品的缺陷,有人提出的技術方案:係將連續鑄造用鑄模內的熔鋼的流動,維持在合宜的狀態的作法。 Conventionally, in order to prevent defects such as deoxidation products, argon bubbles, and mold powder in the molten steel from being caught by the solidified cast piece outer casing, there has been a proposal that the molten steel in the continuous casting mold is used. Flow, maintain the proper state of practice.
例如:專利文獻1所揭示的技術,係使用具有:相對於浸漬式噴嘴的鉛直軸呈對稱地配置的一對吐出孔之浸漬式噴嘴的連續鑄造方法,其中,係對於:浸漬式噴嘴的浸漬深度、在鑄模1/4寬度處的吐出流的最大流速、吐出孔的吐出角度加以規定,並且,將來自浸漬式噴嘴之吐出流的吐出方向與鑄模長邊所形成的角度予以調整成:在水平面上係為3~7°。將吐出流的吐出方向與鑄模長邊所形成的角度予以調整成:3~7°之目的,係想要使得吐出流的至少一部分接觸到鑄模長邊側的凝固鑄片外殼,藉此,可使得吐出流的流速衰減。 For example, the technique disclosed in Patent Document 1 uses a continuous casting method having a pair of discharge nozzles that are symmetrically arranged with respect to the vertical axis of the immersion nozzle, wherein the immersion nozzle is impregnated. The depth, the maximum flow velocity of the discharge flow at the width of the mold 1/4, and the discharge angle of the discharge hole are defined, and the discharge direction of the discharge flow from the immersion nozzle and the angle formed by the long side of the mold are adjusted: The horizontal plane is 3~7°. The angle between the discharge direction of the discharge flow and the long side of the mold is adjusted to be 3 to 7°, so that at least a part of the discharge flow is intended to contact the solidified cast piece outer casing on the long side of the mold, thereby The flow rate of the spit outflow is attenuated.
[先前技術文獻] [Previous Technical Literature]
[專利文獻] [Patent Literature]
專利文獻1:日本特許第4285345號公報 Patent Document 1: Japanese Patent No. 4285345
專利文獻2:日本特許第5742992號公報 Patent Document 2: Japanese Patent No. 5,742,992
然而,上述的習知技術係有下述的問題。 However, the above-mentioned conventional techniques have the following problems.
即,隨著近年來的汽車外板用鋼板等之品質要求的嚴格化,以往並不被視為問題之起因於微小氣泡、鑄模粉的捲入所導致的缺陷,也被視為問題,因此,只依照傳統方法的話,無法充分地對應這樣嚴格的品質要求。尤其是合金化熔融鍍鋅鋼板,係在熔融鍍鋅後,又進行加熱來使得母材鋼板的鐵成分擴散到鍍鋅層,因此,母材鋼板的表層性狀對於合金化熔融鍍鋅層的品質有很大的影響。即,如果母材鋼板的表層具有氣泡性或鑄模粉性的缺陷的話,即使是很小的缺陷,也會導致鍍鋅層的厚度參差不齊,這個部分將會在鋼板表面顯現出條紋狀的缺陷,因而就無法使用在:汽車外板用鋼板之類的對於品質要求很嚴格的用途。 In other words, with the stricter quality requirements of steel sheets for automobile exterior panels in recent years, defects caused by the intrusion of fine bubbles and mold powder, which are not considered to be problems in the past, are also considered as problems. According to the traditional method, such strict quality requirements cannot be fully met. In particular, the alloyed hot-dip galvanized steel sheet is heated and then heated to diffuse the iron component of the base material steel sheet to the galvanized layer. Therefore, the surface properties of the base material steel sheet are good for the quality of the alloyed hot-dip galvanized layer. Have a great impact. That is, if the surface layer of the base metal sheet has the defects of bubble or mold powder, even a small defect may cause the thickness of the galvanized layer to be uneven, and this portion will appear striped on the surface of the steel sheet. Defects, so it can not be used in the use of steel plates for automotive exterior panels for quality requirements.
專利文獻1,係嘗試藉由調整:浸漬式噴嘴吐出孔的浸漬深度、形狀、以及來自浸漬式噴嘴的吐出方向,來控制鑄模內熔鋼流動。一般而言,為了抑制夾雜物(主要是Al2O3)附著到浸漬式噴嘴的內壁,在澆鑄槽流出孔與浸漬式噴嘴吐出孔之間,吹入氬氣或氮氣之類的鈍氣。這種氣體的吹入被認為是:對於吐出噴流的舉動所造 成的影響非常大,而且熔鋼吞吐量當然也會對於吐出噴流的舉動造成很大的影響。如果不將氣體吹入量、熔鋼吞吐量控制在合宜的範圍內,而只是調整浸漬式噴嘴的設計事項的話,其所獲得的流動控制效果並不足,無法適用於汽車外板用鋼板之類的品質要求嚴格的鋼材的製造。 Patent Document 1 attempts to control the flow of molten steel in a mold by adjusting the immersion depth and shape of the immersion nozzle discharge hole and the discharge direction from the immersion nozzle. In general, in order to suppress adhesion of inclusions (mainly Al 2 O 3 ) to the inner wall of the immersion nozzle, between the casting tank outlet hole and the immersion nozzle discharge hole, an argon gas such as argon gas or nitrogen gas is blown. . The insufflation of such a gas is considered to have a very large influence on the behavior of the spouting jet, and the molten steel throughput certainly has a great influence on the behavior of the spouting jet. If the gas injection amount and the molten steel throughput are not controlled within a suitable range, but only the design of the immersion nozzle is adjusted, the flow control effect obtained is insufficient, and it cannot be applied to a steel plate for an automobile outer panel or the like. The quality of the steel requires strict manufacturing.
本發明係有鑒於上述的問題而進行開發完成的,其目的係想要提供:不僅將來自浸漬式噴嘴的熔鋼的吐出位置、浸漬式噴嘴形狀、熔鋼吞吐量、吹入鈍氣的流量等予以控制在合宜的範圍內,也將浸漬式噴嘴的吐出方向調整到合宜的方向來控制鑄模內的熔鋼流動,而能夠製造高品質的鋼胚鑄片之連續鑄造方法。進而提供:針對於各種的鑄模內電磁流動控制技術,提示合宜的浸漬式噴嘴吐出方向,而能夠製造出更少夾雜物的高品質鋼胚鑄片之連續鑄造方法。 The present invention has been made in view of the above problems, and an object thereof is to provide not only a discharge position of a molten steel from an immersion nozzle, an immersion nozzle shape, a molten steel throughput, and a flow rate of blowing an blunt gas. It is also possible to control the continuous casting method of the high-quality steel blank cast piece by controlling the discharge direction of the dipping nozzle to a suitable direction to control the flow of the molten steel in the mold. Further, a continuous casting method for high-quality steel slabs capable of producing less inclusions is provided for various electromagnetic flow control technologies in the mold, suggesting a suitable immersion nozzle discharge direction.
用以解決這種技術課題之本發明的技術特徵,係如下所述。 The technical features of the present invention for solving such technical problems are as follows.
[1]一種鋼胚鑄片之連續鑄造方法,係將浸漬式噴嘴配置在連續鑄造用鑄模內,將熔鋼供給到該浸漬式噴嘴,以將該熔鋼進行鑄造之連續鑄造方法,其中,前述浸漬式噴嘴係具有:相對於其鉛直軸呈對稱地配置之一對吐出孔,將前述浸漬式噴嘴的浸漬深度(從鑄模內熔鋼湯面起迄前述吐出孔上端的距離)設定為180mm以上且未達 300mm;將前述吐出孔之從水平方向朝下的熔鋼吐出角度設定在15~35°的範圍內;將被吹入到從澆鑄槽流出孔起迄前述吐出孔之間的鈍氣的流量A(NL/min)與熔鋼吞吐量P(ton/min)的比值A/P設定在2.0~3.5NL/ton的範圍內,將前述浸漬式噴嘴的吐出方向設定成:通過前述浸漬式噴嘴的鉛直軸中心,並且相對於與鑄模長邊面平行的基準面,係在下列數式(1)的範圍內呈傾斜,θ-6≦α≦θ+10...數式(1) [1] A continuous casting method for a steel slab, which is a continuous casting method in which a immersion nozzle is disposed in a casting mold for continuous casting, and molten steel is supplied to the immersion nozzle to cast the molten steel. The immersion nozzle has one pair of discharge holes arranged symmetrically with respect to the vertical axis thereof, and the immersion depth of the immersion nozzle (the distance from the molten steel soup surface in the mold to the upper end of the discharge hole) is set to 180 mm. Above and not reached 300mm; the molten steel discharge angle of the discharge hole facing downward from the horizontal direction is set in the range of 15 to 35°; the flow rate A of the blunt gas which is blown into the discharge hole from the casting groove outflow hole to the discharge hole The ratio A/P of (NL/min) to the molten steel throughput P (ton/min) is set in the range of 2.0 to 3.5 NL/ton, and the discharge direction of the above-described immersion nozzle is set to be passed through the aforementioned immersion nozzle. The center of the vertical axis, and the reference plane parallel to the long side surface of the mold, is inclined within the range of the following formula (1), θ-6≦α≦θ+10. . . Number (1)
在數式(1)中,α係將前述連續鑄造用鑄模從鉛直上方觀看時,前述浸漬式噴嘴的吐出方向之相對於前述基準面的傾斜角度(°);θ係將前述連續鑄造用鑄模從鉛直上方觀看時,從前述浸漬式噴嘴的鉛直軸中心起朝向鑄模長邊與鑄模短邊的接觸點的直線與前述基準面所形成的角度(銳角),並且係由下列的數式(2)所定義的角度(°),tanθ=(D/2)/(W/2)...數式(2) In the equation (1), when the continuous casting mold is viewed from the upper side, the α is the inclination angle (°) with respect to the reference surface in the discharge direction of the immersion nozzle; θ is the continuous casting mold. When viewed from the upper side, the angle formed by the straight line from the center of the vertical axis of the immersion nozzle toward the contact point between the long side of the mold and the short side of the mold and the reference plane (an acute angle) is determined by the following formula (2) ) defined angle (°), tan θ = (D / 2) / (W / 2). . . Number (2)
在數式(2)中,D係被連續鑄造的鋼胚鑄片的厚度(mm);W係被連續鑄造的鋼胚鑄片的寬度(mm)。 In the formula (2), D is the thickness (mm) of the continuously cast steel blank cast piece; W is the width (mm) of the continuously cast steel blank cast piece.
[2]如[1]所述的鋼胚鑄片之連續鑄造方法,其係在連續鑄造中或連續鑄造中之鑄模寬度變更結束後,進行測定前述α,如果前述α未符合前述數式(1)的話,就以謀求符合前述數式(1)的關係的方式來變更前述浸漬式噴嘴的吐出方向。 [2] The continuous casting method for a steel slab according to [1], wherein the α is determined after the change of the width of the mold in continuous casting or continuous casting, if the α does not satisfy the aforementioned formula ( In the case of 1), the discharge direction of the immersion nozzle is changed so as to satisfy the relationship of the above formula (1).
[3]如[1]所述的鋼胚鑄片之連續鑄造方法,其係在前述鑄模長邊的背面,配置:隔介著前述鑄模長邊而相對向之一對上部磁極與一對下部磁極,將前述吐出孔的位置設在:由前述上部磁極所施加的直流靜磁場的最大值的位置與由前述下部磁極所施加的直流靜磁場的最大值的位置之間,利用前述上部磁極與前述下部磁極施加直流靜磁場來對於熔鋼流進行制動,如果由前述上部磁極所施加的直流靜磁場的強度係1500Gs以上且未達2500Gs(高斯;1Gs=10-4T)的話,就將前述浸漬式噴嘴的吐出方向之相對於前述基準面呈傾斜的範圍,由下列數式(3)來取代上述數式(1);如果前述直流靜磁場的強度係2500Gs以上且未達3500Gs的話,就將前述浸漬式噴嘴的吐出方向之相對於前述基準面呈傾斜的範圍,由下列數式(4)來取代上述數式(1),θ≦α≦θ+5...數式(3) [3] The continuous casting method of a steel slab according to [1], which is disposed on a back surface of a long side of the mold, and is disposed opposite to the upper magnetic pole and the pair of lower portions via the long side of the mold. a magnetic pole, wherein a position of the discharge hole is set between a position of a maximum value of a DC static magnetic field applied by the upper magnetic pole and a position of a maximum value of a DC static magnetic field applied by the lower magnetic pole, and the upper magnetic pole is used The lower magnetic pole applies a DC static magnetic field to brake the molten steel flow. If the intensity of the DC static magnetic field applied by the upper magnetic pole is 1500 Gs or more and less than 2500 Gs (Gauss; 1 Gs = 10 -4 T), the foregoing The discharge direction of the immersion nozzle is inclined with respect to the reference plane, and the above formula (1) is replaced by the following formula (3); if the intensity of the DC static magnetic field is 2500 Gs or more and less than 3500 Gs, The range in which the discharge direction of the immersion nozzle is inclined with respect to the reference plane is replaced by the following formula (4), θ ≦ α ≦ θ + 5. . . Equation (3)
θ+6≦α≦θ+10...數式(4)。 θ+6≦α≦θ+10. . . Equation (4).
[4]如[3]所述的鋼胚鑄片之連續鑄造方法,其係在連續鑄造中或連續鑄造中之鑄模寬度變更結束後,進行測定前述α,如果前述直流靜磁場的強度係1500Gs以上且未達2500Gs,並且前述α未符合前述數式(3)的話,就變更前述浸漬式噴嘴的吐出方向,來謀求符合前述數式(3)的關係,如果前述直流靜磁場的強度係2500Gs以上且未達3500Gs,並且前述α未符合前述數式(4)的話,就以謀 求符合前述數式(4)的關係的方式來變更前述浸漬式噴嘴的吐出方向。 [4] The continuous casting method for steel slabs according to [3], wherein the measurement of the aforementioned α is performed after continuous change of the mold width in continuous casting or continuous casting, if the strength of the DC static magnetic field is 1500 Gs. When the above α is less than 2500 Gs, and the above α does not satisfy the above formula (3), the discharge direction of the immersion nozzle is changed to obtain the relationship according to the above formula (3), and the intensity of the DC static magnetic field is 2500 Gs. If the above α does not reach 3500 Gs, and the aforementioned α does not conform to the above formula (4), The discharge direction of the immersion nozzle is changed so as to satisfy the relationship of the above formula (4).
[5]如[1]所述的鋼胚鑄片之連續鑄造方法,其係在前述鑄模長邊的背面,設置:磁場的移動方向係為鑄模寬度方向之直線型移動磁場發生裝置,為了對於自前述浸漬式噴嘴吐出的熔鋼流賦予制動力,乃施加從前述鑄模短邊側朝向前述浸漬式噴嘴側的移動磁場;或者,為了賦予熔鋼流加速力,乃施加從前述浸漬式噴嘴側朝向前述鑄模短邊側的移動磁場,來控制流動,並且將前述浸漬式噴嘴的吐出方向之相對於前述基準面呈傾斜的範圍,由下列數式(5)來取代上述數式(1),θ+2≦α≦θ+7...數式(5)。 [5] The continuous casting method of the steel slab according to [1], which is provided on the back side of the long side of the mold, and is provided with a linear moving magnetic field generating device in which the moving direction of the magnetic field is the width direction of the mold, The molten steel flow discharged from the immersion nozzle imparts a braking force to the moving magnetic field from the short side of the mold toward the immersion nozzle side, or is applied from the immersion nozzle side in order to impart an acceleration force to the molten steel flow. The flow is controlled toward the moving magnetic field on the short side of the mold, and the range of the discharge direction of the immersion nozzle is inclined with respect to the reference surface, and the above formula (5) is replaced by the following formula (5). θ+2≦α≦θ+7. . . Equation (5).
[6]如[5]所述的鋼胚鑄片之連續鑄造方法,其係在連續鑄造中或連續鑄造中之鑄模寬度變更結束後,進行測定前述α,如果前述α未符合前述數式(5)的話,就以謀求符合前述數式(5)的關係的方式來變更前述浸漬式噴嘴的吐出方向。 [6] The continuous casting method for a steel slab according to [5], wherein the α is determined after the change of the width of the mold in continuous casting or continuous casting, if the α does not satisfy the aforementioned formula ( In the case of 5), the discharge direction of the immersion nozzle is changed so as to satisfy the relationship of the above formula (5).
[7]如[1]所述的鋼胚鑄片之連續鑄造方法,其係在前述鑄模長邊的背面,配置:隔介著前述鑄模長邊而相對向之一對磁極,從前述磁極施加交流移動磁場來對於熔鋼進行水平方向上的迴旋攪拌,除了將前述交流移動磁場的強度設定在300~1000Gs的範圍內之外,如果前述交流移動磁場的強度X(Gs)與被連續鑄造的鋼胚鑄片的寬度 W(mm)的比值X/W(Gs/mm)係0.30以上且未達0.45的話,就將前述浸漬式噴嘴的吐出方向設成:朝向由前述交流移動磁場所形成的迴旋流的上游側,並且將相對於前述基準面呈傾斜的範圍,由下列數式(6)來取代上述數式(1),如果前述比值X/W(Gs/mm)係0.45以上且未達0.55的話,將相對於前述基準面呈傾斜的範圍,由下列數式(7)來取代上述數式(1),θ-3≦α≦θ...數式(6) [7] The continuous casting method for a steel slab according to [1], wherein the back surface of the long side of the mold is disposed to face a pair of magnetic poles with respect to a long side of the mold, and is applied from the magnetic pole The alternating moving magnetic field is used to perform the cyclotron stirring in the horizontal direction of the molten steel, except that the intensity of the alternating magnetic moving magnetic field is set in the range of 300 to 1000 Gs, if the intensity X (Gs) of the alternating magnetic moving magnetic field is continuously cast Width of steel slab When the ratio X/W (Gs/mm) of W (mm) is 0.30 or more and less than 0.45, the discharge direction of the immersion nozzle is set to the upstream side of the swirling flow formed by the alternating magnetic field. And the range (1) is replaced by the following formula (6) in a range inclined with respect to the reference plane, and if the ratio X/W (Gs/mm) is 0.45 or more and less than 0.55, In the range in which the reference plane is inclined, the above formula (1), θ-3≦α≦θ is replaced by the following formula (7). . . Number (6)
θ-6≦α≦θ-4...數式(7)。 ≦-6≦α≦θ-4. . . Equation (7).
[8]如[7]所述的鋼胚鑄片之連續鑄造方法,其係在連續鑄造中或連續鑄造中之鑄模寬度變更結束後,進行測定前述α,如果前述比值X/W(Gs/mm)係0.30以上且未達0.45,而且前述α未符合前述數式(6)的話,就變更前述浸漬式噴嘴的吐出方向,來謀求符合前述數式(6)的關係;如果前述比值X/W(Gs/mm)係0.45以上且未達0.55,而且前述α未符合前述數式(7)的話,就以謀求符合前述數式(7)的關係的方式來變更前述浸漬式噴嘴的吐出方向。 [8] The continuous casting method for steel slabs according to [7], wherein the above-mentioned α is measured after continuous change of the mold width in continuous casting or continuous casting, if the ratio X/W (Gs/) When the mm is 0.30 or more and less than 0.45, and the above α does not satisfy the above formula (6), the discharge direction of the immersion nozzle is changed to obtain the relationship according to the above formula (6); if the ratio X/ When W (Gs/mm) is 0.45 or more and less than 0.55, and the above-mentioned α does not satisfy the above formula (7), the discharge direction of the immersion nozzle is changed so as to satisfy the relationship of the above formula (7). .
[9]如[1]所述的鋼胚鑄片之連續鑄造方法,其係在前述鑄模長邊的背面,配置:隔介著前述鑄模長邊而相對向之一對上部磁極與一對下部磁極,將前述吐出孔的位置設在:由前述上部磁極所施加的直流靜磁場的最大值的位置與由前述下部磁極所施加的直流靜磁場的最大值的位置之間,從前述上部磁極重疊地施加直流靜磁場與交流移動 磁場,利用前述上部磁極所施加的交流移動磁場,在鑄模內熔鋼湯面形成在水平方向上進行旋轉的熔鋼的迴旋流,利用前述上部磁極所施加的直流靜磁場來對於熔鋼流進行制動,並且利用前述下部磁極所施加的直流靜磁場來對於熔鋼流進行制動,除了將前述交流移動磁場的強度設定在500~900Gs(高斯;1Gs=10-4T)的範圍內,將前述上部磁極所施加的直流靜磁場的強度設定在2000~3300Gs的範圍內,將前述下部磁極所施加的直流靜磁場的強度設定在3000~4500Gs的範圍內之外,又將前述交流移動磁場的強度X(Gs)與被連續鑄造的鋼胚鑄片的寬度W(mm)的比值X/W(Gs/mm)控制在0.30以上且未達0.55,同時將前述浸漬式噴嘴的吐出方向設定成:朝向由前述交流移動磁場所形成的前述熔鋼的迴旋流的上游側,並且相對於前述基準面係呈傾斜。 [9] The continuous casting method for a steel slab according to [1], which is disposed on a back surface of a long side of the mold, and is disposed opposite to the upper magnetic pole and the pair of lower portions via the long side of the mold. a magnetic pole, wherein a position of the discharge hole is provided between a position at which a maximum value of a DC static magnetic field applied by the upper magnetic pole and a maximum value of a DC static magnetic field applied by the lower magnetic pole are overlapped from the upper magnetic pole Applying a DC static magnetic field and an AC moving magnetic field, and using the AC moving magnetic field applied by the upper magnetic pole to form a swirling flow of the molten steel rotating in the horizontal direction in the molten steel soup surface in the mold, and using the DC applied by the upper magnetic pole The static magnetic field brakes the molten steel flow, and uses the DC static magnetic field applied by the lower magnetic pole to brake the molten steel flow, except that the intensity of the aforementioned alternating moving magnetic field is set at 500 to 900 Gs (Gauss; 1 Gs = 10 -4) In the range of T), the intensity of the DC static magnetic field applied by the upper magnetic pole is set in the range of 2000 to 3300 Gs, and the DC static magnetic field applied by the lower magnetic pole is set. The intensity is set in the range of 3,000 to 4,500 Gs, and the ratio X/W (Gs/mm) of the intensity X (Gs) of the AC moving magnetic field to the width W (mm) of the continuously cast steel slab is controlled. The discharge direction of the immersion nozzle is set to be on the upstream side of the swirling flow of the molten steel formed by the alternating-current moving magnetic field, and is inclined with respect to the reference surface, at 0.30 or more and less than 0.55.
[10]如[9]所述的鋼胚鑄片之連續鑄造方法,其中,如果前述比值X/W(Gs/mm)係0.30以上且未達0.45的話,就將前述浸漬式噴嘴的吐出方向之相對於前述基準面呈傾斜的範圍,由下列數式(8)來取代上述數式(1);如果前述比值X/W(Gs/mm)係0.45以上且未達0.55的話,就將前述浸漬式噴嘴的吐出方向之相對於前述基準面呈傾斜的範圍,由下列數式(9)來取代上述數式(1),θ-2≦α≦θ+5...數式(8) [10] The continuous casting method of a steel slab according to [9], wherein the discharge direction of the immersion nozzle is set if the ratio X/W (Gs/mm) is 0.30 or more and less than 0.45. In the range in which the reference plane is inclined with respect to the reference plane, the above formula (1) is replaced by the following formula (8); if the ratio X/W (Gs/mm) is 0.45 or more and less than 0.55, the foregoing The discharge direction of the immersion nozzle is inclined with respect to the reference plane, and the above formula (1) is replaced by the following formula (9), θ-2 ≦ α ≦ θ + 5. . . Number (8)
θ-5≦α≦θ+2...數式(9)。 Θ-5≦α≦θ+2. . . Equation (9).
[11]如[10]所述的鋼胚鑄片之連續鑄造方法,其係 在連續鑄造中或連續鑄造中之鑄模寬度變更結束後,進行測定前述α,如果前述比值X/W(Gs/mm)係0.30以上且未達0.45,而且前述α未符合前述數式(8)的話,就變更前述浸漬式噴嘴的吐出方向,來謀求符合前述數式(8)的關係;如果前述比值X/W(Gs/mm)係0.45以上且未達0.55,而且前述α未符合前述數式(9)的話,就以謀求符合前述數式(9)的關係的方式來變更前述浸漬式噴嘴的吐出方向。 [11] The continuous casting method for steel slabs as described in [10], After the change of the mold width in continuous casting or continuous casting is completed, the above α is measured, and if the ratio X/W (Gs/mm) is 0.30 or more and less than 0.45, and the aforementioned α does not satisfy the above formula (8) In the case of changing the discharge direction of the immersion nozzle, the relationship of the above formula (8) is obtained. If the ratio X/W (Gs/mm) is 0.45 or more and less than 0.55, the α does not satisfy the above number. In the case of the formula (9), the discharge direction of the immersion nozzle is changed so as to satisfy the relationship of the above formula (9).
根據本發明,除了將浸漬式噴嘴形狀、熔鋼吞吐量、吹入鈍氣的流量等,控制在合宜的範圍內,也將浸漬式噴嘴的吐出方向調整到適切的方向,藉此,可適切地控制鑄模內的熔鋼流動,而可達成製造出高品質的鋼胚鑄片。此外,針對於各種的鑄模內電磁流動控制條件,藉由控制成:合宜的浸漬式噴嘴的吐出方向,而可達成製造出夾雜物更少之高品質鋼胚鑄片。 According to the present invention, in addition to controlling the shape of the immersion nozzle, the throughput of the molten steel, the flow rate of the blown air, and the like, it is controlled within a suitable range, and the discharge direction of the immersion nozzle is also adjusted to an appropriate direction, thereby being adapted. The flow of molten steel in the mold is controlled to achieve high quality steel slab casting. Further, for various electromagnetic flow control conditions in the mold, by controlling the discharge direction of the appropriate immersion nozzle, it is possible to produce a high-quality steel slab having less inclusions.
1‧‧‧連續鑄造用鑄模 1‧‧‧Continuous casting mold
2‧‧‧鑄模長邊 2‧‧‧Molded long side
3‧‧‧鑄模短邊 3‧‧‧Molded short side
4‧‧‧浸漬式噴嘴 4‧‧‧Dip nozzle
5‧‧‧吐出孔 5‧‧‧Spit hole
6‧‧‧上部磁極 6‧‧‧Upper magnetic pole
7‧‧‧下部磁極 7‧‧‧lower magnetic pole
8‧‧‧熔鋼 8‧‧‧Fused steel
9‧‧‧凝固鑄片外殼 9‧‧‧ Solidified cast shell
10‧‧‧鑄模內熔鋼湯面 10‧‧‧Molded steel noodle soup in mold
11‧‧‧吐出流 11‧‧‧Spit out
12‧‧‧交流移動磁場發生線圈 12‧‧‧AC moving magnetic field generating coil
13‧‧‧直流靜磁場發生線圈 13‧‧‧DC static magnetic field generating coil
14‧‧‧直流靜磁場發生線圈 14‧‧‧DC static magnetic field generating coil
15‧‧‧迴旋流 15‧‧‧ whirlpool
16‧‧‧反轉流 16‧‧‧ Reverse flow
17‧‧‧低流速領域 17‧‧‧Low flow rate field
18‧‧‧渦流 18‧‧‧ eddy current
19‧‧‧下降流 19‧‧‧ Downstream
20‧‧‧連續鑄造用鑄模 20‧‧‧Continuous casting mold
30‧‧‧連續鑄造用鑄模 30‧‧‧Continuous casting mold
40‧‧‧連續鑄造用鑄模 40‧‧‧Continuous casting mold
42‧‧‧直線型移動磁場發生裝置 42‧‧‧Linear moving magnetic field generating device
50‧‧‧連續鑄造用鑄模 50‧‧‧Continuous casting mold
52‧‧‧磁極 52‧‧‧ magnetic pole
第1圖係將連續鑄造用鑄模之一例從鑄模長邊側觀看時的概略剖面圖。 Fig. 1 is a schematic cross-sectional view showing an example of a continuous casting mold as viewed from the long side of the mold.
第2圖係顯示來自連續鑄造用鑄模中的浸漬式噴嘴之吐出流的狀態之概略剖面圖。 Fig. 2 is a schematic cross-sectional view showing a state of a discharge flow from an immersion nozzle in a continuous casting mold.
第3圖係從鉛直上方來觀看將浸漬式噴嘴的吐出方向予以傾斜來進行鑄造時的樣子之概略圖。 Fig. 3 is a schematic view showing a state in which the discharge direction of the immersion nozzle is inclined and the casting is performed from the vertical upper side.
第4圖係與第1圖不同之別種連續鑄造用鑄模的概略剖面圖。 Fig. 4 is a schematic cross-sectional view showing a mold for continuous casting which is different from Fig. 1 .
第5圖係從鉛直上方來觀看第4圖時的概略剖面圖。 Fig. 5 is a schematic cross-sectional view when the fourth figure is viewed from the upper side.
第6圖係與第1圖及第4圖不同之別種連續鑄造用鑄模的概略剖面圖。 Fig. 6 is a schematic cross-sectional view showing a mold for continuous casting which is different from the first and fourth drawings.
第7圖係從鉛直上方來觀看第6圖時的概略剖面圖。 Fig. 7 is a schematic cross-sectional view when the sixth figure is viewed from the upper side.
第8圖係與第1圖、第4圖及第6圖不同之別種連續鑄造用鑄模的概略剖面圖。 Fig. 8 is a schematic cross-sectional view showing a mold for continuous casting different from the first, fourth, and sixth drawings.
第9圖係從鉛直上方來觀看第8圖時的概略剖面圖。 Fig. 9 is a schematic cross-sectional view showing the eighth figure from the vertical upper side.
第10圖係將吐出方向設定成垂直於鑄模短邊的鑄造條件下之鑄模內的熔鋼流速狀況的示意圖。 Fig. 10 is a schematic view showing the flow direction of the molten steel in the mold under casting conditions perpendicular to the short side of the mold.
第11圖從鉛直上方來觀看將吐出方向予以傾斜來進行鑄造時的樣子之概略圖。 Fig. 11 is a schematic view showing a state in which the direction of the discharge is inclined and the casting is performed from the vertical upper side.
第12圖係與第1圖、第4圖、第6圖及第8圖不同之別種連續鑄造用鑄模的概略剖面圖。 Fig. 12 is a schematic cross-sectional view showing a mold for continuous casting which is different from Fig. 1, Fig. 4, Fig. 6, and Fig. 8.
第13圖係第12圖的上部磁極的部位之概略橫剖面圖。 Fig. 13 is a schematic cross-sectional view showing a portion of the upper magnetic pole of Fig. 12.
第14圖係第12圖的下部磁極的部位之概略橫剖面圖。 Fig. 14 is a schematic cross-sectional view showing a portion of the lower magnetic pole of Fig. 12.
第15圖係將來自浸漬式噴嘴的吐出方向設定成垂直於鑄模短邊的鑄造條件下之鑄模內的熔鋼流速狀況的示意圖。 Fig. 15 is a view showing the flow direction of the molten steel in the mold under the casting condition perpendicular to the short side of the mold, with the discharge direction from the immersion nozzle being set.
第16圖從鉛直上方來觀看將浸漬式噴嘴的吐出方向予以朝迴旋流的上游側傾斜來進行鑄造時的樣子之概略圖。 Fig. 16 is a schematic view showing a state in which the discharge direction of the immersion nozzle is inclined toward the upstream side of the swirling flow when the casting direction is performed.
第17圖係顯示將吐出方向的傾斜角度α進行變更處理之一例的流程圖。 Fig. 17 is a flowchart showing an example of a process of changing the inclination angle α of the discharge direction.
第18圖係顯示與第17圖不同的別種例子的流程圖。 Fig. 18 is a flow chart showing another example different from Fig. 17.
第19圖係顯示與第17圖及第18圖不同的別種例子的流程圖。 Fig. 19 is a flow chart showing another example different from Fig. 17 and Fig. 18.
第20圖係顯示與第17圖~第19圖不同的別種例子的流程圖。 Fig. 20 is a flow chart showing another example different from Fig. 17 to Fig. 19.
第21圖係顯示與第17圖~第20圖不同的別種例子的流程圖。 Fig. 21 is a flow chart showing another example different from Fig. 17 to Fig. 20.
第22圖係顯示將第17圖~第21圖的各種處理依據鑄造條件的不同來分開使用進行處理之一例的流程圖。 Fig. 22 is a flow chart showing an example in which the various processes of Figs. 17 to 21 are separately used depending on the casting conditions.
第23圖係將本發明例19~38之「α-θ」與「製品缺陷指數」的關係,以2500(Gs)的靜磁場強度為境界,予以分區顯示的圖。 Fig. 23 is a diagram showing the relationship between "α-θ" and "product defect index" of Examples 19 to 38 of the present invention, and the static magnetic field strength of 2500 (Gs) is used as a boundary.
第24圖係顯示本發明例39~49之「α-θ」與「製品缺陷指數」的關係之圖。 Fig. 24 is a graph showing the relationship between "α-θ" and "product defect index" in Examples 39 to 49 of the present invention.
第25圖係將本發明例50~71之「α-θ」與「製品缺陷指數」的關係,以X/W的比值0.45為境界,予以分區顯示的圖。 Fig. 25 is a diagram showing the relationship between "α-θ" and "product defect index" of Examples 50 to 71 of the present invention, with a ratio of X/W of 0.45 as a boundary.
第26圖係將本發明例83~106之「α-θ」與「製品缺陷指數」的關係,以X/W的比值0.45為境界,予以分 區顯示的圖。 Figure 26 is a diagram showing the relationship between "α-θ" and "product defect index" of Examples 83 to 106 of the present invention, and the ratio of X/W is 0.45. The map displayed by the area.
以下,將透過發明的實施方式來詳細說明本發明。第1圖係顯示可適用於本實施方式的連續鑄造方法之鋼胚連續鑄造機的連續鑄造用鑄模20之一例,並且是從鑄模長邊側來觀看連續鑄造用鑄模20時的剖面圖。鋼胚鑄片用的連續鑄造用鑄模20,係由:相對向的一對鑄模長邊2、相對向的一對鑄模短邊3組合而構成的。在由一對鑄模長邊與一對鑄模短邊所圍繞而成的鑄模內部空間內,係配置有浸漬式噴嘴4,熔鋼8係從浸漬式噴嘴4的吐出孔5注入鑄模內部空間,來進行熔鋼8的連續鑄造。吐出孔5係相對於浸漬式噴嘴4的鉛直軸呈左右對稱地配置在浸漬式噴嘴4的側壁。從吐出孔5注入的熔鋼8,係形成吐出流而朝向左右的鑄模短邊3的方向吐出。被注入到鑄模內部空間的熔鋼8,接觸到鑄模長邊2及鑄模短邊3而被冷卻,而在與鑄模長邊2及鑄模短邊3進行接觸的接觸面形成凝固鑄片外殼9。以這種凝固鑄片外殼9作為外殼而在內部還有尚未凝固的熔鋼8之鋼胚鑄片,係呈連續性地被往下方拉拔,而被製成鋼胚鑄片。此時,在鑄模內的熔鋼湯面10上,係被添加可發揮:潤滑劑、保溫劑、氧化防止劑等的功能的鑄模粉(未圖示)。又,為了防止夾雜物附著到浸漬式噴嘴4的內面,在澆鑄槽流出孔(未圖示)至浸漬式噴嘴4的吐出孔5之間,係被吹入氬 氣、氮氣等。 Hereinafter, the present invention will be described in detail through embodiments of the invention. 1 is an example of a continuous casting mold 20 which can be applied to the continuous casting method of the present embodiment, and is a cross-sectional view when the continuous casting mold 20 is viewed from the long side of the mold. The continuous casting mold 20 for a steel slab is composed of a pair of opposed mold long sides 2 and a pair of opposed mold short sides 3 combined. In the inner space of the mold surrounded by the long sides of the pair of molds and the short sides of the pair of molds, the immersion nozzle 4 is disposed, and the molten steel 8 is injected into the inner space of the mold from the discharge hole 5 of the immersion nozzle 4. Continuous casting of the molten steel 8 is performed. The discharge hole 5 is disposed on the side wall of the immersion nozzle 4 in a bilaterally symmetrical manner with respect to the vertical axis of the immersion nozzle 4 . The molten steel 8 injected from the discharge hole 5 is discharged in the direction of the short side 3 of the right and left molds by forming a discharge flow. The molten steel 8 injected into the inner space of the mold is cooled by contact with the long side 2 of the mold and the short side 3 of the mold, and a solidified cast piece casing 9 is formed on the contact surface which is in contact with the long side 2 of the mold and the short side 3 of the mold. The solidified cast piece casing 9 is used as a casing, and a steel slab of molten steel 8 which has not been solidified inside is continuously drawn downward to be formed into a steel slab. At this time, a mold powder (not shown) which functions as a lubricant, a heat retaining agent, an oxidation preventive agent, or the like is added to the molten steel noodle soup 10 in the mold. Further, in order to prevent the inclusions from adhering to the inner surface of the immersion nozzle 4, argon is blown between the casting tank outflow holes (not shown) to the discharge holes 5 of the immersion nozzle 4. Gas, nitrogen, etc.
將第1圖所示的鑄造條件下的鑄模內的流動舉動,藉由:數值計算、實際機器的1/1水模型裝置、使用低融點合金(Bi-Pb-Sn-Cd合金;融點約70℃)之實際機器的1/4尺寸的試驗鑄造裝置來進行流速測定,反覆數次進行了確認。此時,尤其是著眼於吐出流11的流動舉動,嘗試將鑄模內流動的適正化條件予以定量化。 The flow behavior in the mold under the casting conditions shown in Fig. 1 is calculated by numerical calculation, 1/1 water model device of the actual machine, and low-melting alloy (Bi-Pb-Sn-Cd alloy; melting point) The flow rate measurement was performed on a 1/4-size test casting apparatus of an actual machine of about 70 ° C), and it was confirmed several times in succession. At this time, in particular, focusing on the flow behavior of the discharge stream 11, it is attempted to quantify the proper normalization conditions for the flow in the mold.
第2圖係顯示來自連續鑄造用鑄模中的浸漬式噴嘴的吐出流的狀態之概略剖面圖。可得知:在浸漬式噴嘴4的浸漬深度(由鑄模內熔鋼湯面起迄吐出孔上端為止的距離)為180mm以上且未達300mm,且將吐出孔5之從水平方向朝下方的熔鋼吐出角度設定在15~35°的範圍內之條件下,將吹入到從澆鑄槽流出孔起迄浸漬式噴嘴4的吐出孔5之間的鈍氣的流量A(NL/min)與熔鋼吞吐量P(ton/min)的比值A/P予以控制在2.0~3.5(NL/ton)的範圍內的話,係如第2圖(a)所示般地,吐出流11在抵達鑄模短邊附近後,吐出流11係有朝向彎液面(Meniscus)側浮上的傾向。即,可得知:因為是將鈍氣吹入浸漬式噴嘴4的吐出孔5,因此吐出流11係顯現出上昇舉動(lift up)。由此可知:藉由將相對於熔鋼吞吐量之鈍氣流量比也就是A/P值、浸漬式噴嘴4的浸漬深度、與吐出角度之間的平衡性做適切的控制,就能夠穩定地控制:吐出流11的流動舉動。又,如第2圖(b)所示,如果相對於熔鋼吞吐量P之鈍氣流量A太多的話,吐出流11受到上昇(lift up)效 果,將會提前浮上。可得知:這種提前的吐出流11的浮上,將會助長彎液面產生變動,而很容易將鑄模粉捲入。另一方面,如第2圖(c)所示,亦可得知:如果相對於熔鋼吞吐量P之鈍氣流量A太小的話,吐出流11不易浮上,會直接撞擊到鑄模短邊3而有產生鑄漏之虞慮、對於彎液面側的熔鋼供給變得不穩定,因而對於彎液面的熱供給不足,有引起鑄模粉的熔融不良之可能性。此外,這些創見,係在鑄造寬度為1000~2000(mm)、每一個吐出孔1的面積為4000~10000(mm2)、熔鋼吞吐量為3.0~8.0(ton/min)的範圍內,已經獲得了確認,因此,只要是在這種範圍內的鑄造條件的話,就可以穩定地控制:吐出流11的流動舉動。 Fig. 2 is a schematic cross-sectional view showing a state of a discharge flow from an immersion nozzle in a continuous casting mold. It can be seen that the immersion depth of the immersion nozzle 4 (the distance from the molten steel soup surface in the mold to the upper end of the discharge hole) is 180 mm or more and less than 300 mm, and the discharge hole 5 is melted downward from the horizontal direction. When the steel discharge angle is set in the range of 15 to 35°, the flow rate A (NL/min) of the indulgent gas which is blown between the discharge holes 5 of the immersion nozzle 4 from the outflow hole of the casting groove is melted and melted. When the ratio A/P of the steel throughput P (ton/min) is controlled within the range of 2.0 to 3.5 (NL/ton), as shown in Fig. 2(a), the discharge flow 11 is short in reaching the mold. Immediately after the side, the discharge flow 11 tends to float toward the meniscus side. That is, it can be seen that since the blunt gas is blown into the discharge hole 5 of the immersion nozzle 4, the discharge flow 11 exhibits a lift up. From this, it can be seen that the blunt gas flow ratio with respect to the throughput of the molten steel, that is, the A/P value, the immersion depth of the immersion nozzle 4, and the balance between the discharge angle and the discharge angle can be appropriately controlled. Control: The flow of the discharge stream 11 is discharged. Further, as shown in Fig. 2(b), if the blunt gas flow rate A with respect to the molten steel throughput P is too large, the discharge flow 11 is subjected to a lift up effect and will float upward. It can be known that the floating of the advanced discharge stream 11 will promote the change of the meniscus, and it is easy to wind the mold powder. On the other hand, as shown in Fig. 2(c), it can also be seen that if the blunt gas flow rate A with respect to the molten steel throughput P is too small, the discharge flow 11 is less likely to float and directly hits the short side of the mold 3 On the other hand, there is a concern that the casting leakage occurs, and the supply of the molten steel on the meniscus side becomes unstable. Therefore, the heat supply to the meniscus is insufficient, and there is a possibility that the molten powder of the mold powder is poorly melted. In addition, these innovations are in the range of casting widths of 1000 to 2000 (mm), each of the discharge holes 1 is 4000 to 10000 (mm 2 ), and the molten steel throughput is 3.0 to 8.0 (ton/min). Since it has been confirmed, as long as it is a casting condition within such a range, the flow behavior of the discharge flow 11 can be stably controlled.
其次,本發明人等著眼於:吐出流11的吐出方向加以調查。其結果,係得知:除了如上述般地將吐出流11的上昇舉動做合宜的控制之外,如果朝向鑄模角落部將吐出方向控制在適切的角度範圍內的話,可在彎液面(Meniscus)獲得適度的流速,能夠抑制:發生表面缺陷的原因之氣泡和微小夾雜物暨粉體等被捕捉到凝固鑄片外殼9,藉此,可降低表面缺陷。 Next, the inventors of the present invention paid attention to the investigation of the discharge direction of the discharge flow 11. As a result, it has been found that, in addition to the above-described control of the upward movement of the discharge flow 11 as described above, if the discharge direction is controlled within a suitable angle range toward the corner portion of the mold, it can be in the meniscus (Meniscus By obtaining a moderate flow rate, it is possible to suppress that bubbles and minute inclusions and powders which cause surface defects are caught in the solidified cast piece casing 9, whereby surface defects can be reduced.
第3圖係由鉛直上方來觀看將浸漬式噴嘴的吐出方向傾斜來進行鑄造時的樣子之概略圖。如第3圖所示,假設「通過浸漬式噴嘴4的鉛直軸中心,並且朝向鑄模長邊2與鑄模短邊3的接觸點(鑄模角落部)延伸的直線」以及「與鑄模長邊面平行且通過浸漬式噴嘴4的鉛直 軸中心的基準面」所形成的角度(銳角)為θ(°),θ係使用:被鑄造的鋼胚鑄片的厚度D(mm)與被鑄造的鋼胚鑄片的寬度W(mm),並且利用下列的數式(2)來加以定義(在以下的說明中,也將角度θ稱為「對角線方向角度θ」)。是以,對角線方向角度θ係隨著鋼胚鑄片的橫剖面的尺寸而變化。 Fig. 3 is a schematic view showing a state in which the direction in which the immersion nozzle is ejected obliquely is viewed from the upper side to perform casting. As shown in Fig. 3, it is assumed that "the line passing through the center of the vertical axis of the immersion nozzle 4 and extending toward the contact point (the corner portion of the mold) of the long side 2 of the mold and the short side 3 of the mold" and "the parallel side with the long side of the mold" are assumed. And through the vertical of the immersion nozzle 4 The angle (sharp angle) formed by the reference plane of the center of the shaft is θ (°), and θ is used: the thickness D (mm) of the cast steel slab and the width W (mm) of the cast steel slab It is defined by the following formula (2) (in the following description, the angle θ is also referred to as "diagonal direction angle θ"). Therefore, the diagonal direction angle θ varies depending on the size of the cross section of the steel slab.
tanθ=(D/2)/(W/2)...數式(2) Tan θ = (D / 2) / (W / 2). . . Number (2)
又,如第3圖所示,係將浸漬式噴嘴4的吐出方向傾斜來進行鑄造時,由鉛直上方來觀看連續鑄造用鑄模20時的浸漬式噴嘴4的吐出方向之相對於基準面的傾斜角度,視為α(°)。 In addition, as shown in Fig. 3, when the casting direction of the immersion nozzle 4 is tilted and the casting mold 20 for continuous casting is viewed from the upper side, the inclination of the discharge direction of the immersion nozzle 4 with respect to the reference surface is observed. The angle is treated as α(°).
本發明人等,找到一種創見,係為:除了適正地控制吐出流11的流動舉動之外,如果將相對於基準面的傾斜角度α設定在下列的數式(1)的範圍內的話,可獲得表面缺陷很少之良質的鋼胚鑄片。即,藉由將傾斜角度α控制在數式(1)的範圍內,係能夠獲得可排除表面缺陷因子之適切的流速。 The present inventors have found a finding that, in addition to properly controlling the flow behavior of the discharge flow 11, if the inclination angle α with respect to the reference plane is set within the range of the following formula (1), A steel slab with a few surface defects is obtained. That is, by controlling the inclination angle α within the range of the formula (1), it is possible to obtain a suitable flow velocity at which the surface defect factor can be excluded.
θ-6≦α≦θ+10...數式(1) ≦-6≦α≦θ+10. . . Number (1)
又,如果傾斜角度α小於θ-6的話,係無法獲得適切的流速。此外,如果傾斜角度α大於θ+10的話,吐出流11將會直接衝撞長邊凝固鑄片外殼9,因此,發生鑄漏的風險變大。 Further, if the inclination angle α is smaller than θ-6, a suitable flow velocity cannot be obtained. Further, if the inclination angle α is larger than θ + 10, the discharge flow 11 will directly collide with the long-side solidified cast piece casing 9, and therefore, the risk of occurrence of casting leakage becomes large.
是以,藉由採用本實施方式的連續鑄造方法,不必使用高價的電磁流動線圈設備,即可製造良質的鋼胚鑄片。此外,在本實施方式中,係以厚度220~300(mm)的範圍內的鋼胚鑄片為對象,只要是在該範圍內的厚度的鋼胚的話,即可適用本實施方式的連續鑄造方法。 Therefore, by adopting the continuous casting method of the present embodiment, it is possible to manufacture a good steel blank cast piece without using an expensive electromagnetic flow coil device. Further, in the present embodiment, the steel blank slab in the range of 220 to 300 (mm) is used, and the continuous casting of the present embodiment can be applied as long as it is a steel slab having a thickness within the range. method.
其次,本發明人等,係針對於:使用各種鑄模內電磁流動控制方式的情況下之相對於基準面之最適合的傾斜角度α加以調查。 Next, the inventors of the present invention have investigated the most suitable inclination angle α with respect to the reference surface in the case of using various electromagnetic flow control methods in the mold.
第4圖係與前述不同之別種連續鑄造用鑄模的概略剖面圖。又,第5圖係將第4圖由鉛直上方觀看時的概略剖面圖。鋼胚鑄片用的連續鑄造用鑄模30,係對於第1圖所示的連續鑄造用鑄模20,又在鑄模長邊2的背面,設置有:隔介著鑄模長邊2而相對向的一對上部磁極6與一對下部磁極7。在各個上部磁極6以及下部磁極7,係如第5圖所示,設置有:用來施加直流靜磁場之直流靜磁場發生線圈13。直流靜磁場發生線圈13係被配置成:與被鑄造的鋼胚鑄片的寬度同等程度或者更大。 Fig. 4 is a schematic cross-sectional view showing a mold for continuous casting which is different from the above. In addition, Fig. 5 is a schematic cross-sectional view when the fourth figure is viewed from the upper side. The continuous casting mold 30 for a steel slab is provided for the continuous casting mold 20 shown in Fig. 1 and the opposite side of the long side 2 of the mold. The upper magnetic pole 6 and the pair of lower magnetic poles 7. As shown in Fig. 5, each of the upper magnetic poles 6 and the lower magnetic poles 7 is provided with a DC static magnetic field generating coil 13 for applying a DC static magnetic field. The DC static magnetic field generating coil 13 is arranged to be equal to or larger than the width of the cast steel slab.
藉由從上部磁極6的直流靜磁場發生線圈13所施加的直流靜磁場,在鑄模內熔鋼湯面10的熔鋼流受到制動(減速)。同樣地,藉由從下部磁極7的直流靜磁場發生線圈13所施加的直流靜磁場,在吐出流11之中的想要朝向下方通過直流靜磁場發生線圈13的位置之熔鋼流係受到制動(減速)。此外,浸漬式噴嘴4的吐出孔5,係 設置在:「由上部磁極6所施加的直流靜磁場的最大值的位置」與「由下部磁極7所施加的直流靜磁場的最大值的位置」之間。 The molten steel flow of the molten steel noodle 10 in the mold is braked (decelerated) by the DC static magnetic field applied from the DC static magnetic field generating coil 13 of the upper magnetic pole 6. Similarly, by the DC static magnetic field applied from the DC static magnetic field generating coil 13 of the lower magnetic pole 7, the molten steel flow system in the discharge flow 11 that is intended to pass downward through the DC static magnetic field generating coil 13 is braked. (slow down). Further, the discharge hole 5 of the immersion nozzle 4 is It is provided between "the position of the maximum value of the DC static magnetic field applied by the upper magnetic pole 6" and "the position of the maximum value of the DC static magnetic field applied by the lower magnetic pole 7".
執行這種電磁流動控制的話,熔鋼流係受到靜磁場所制動,因此能夠抑制鑄模粉的被捲入。另一方面,為了抑制氣泡和微小夾雜物被捕捉到凝固鑄片外殼9,也必須賦予熔鋼流具有適度的流速。本發明人等,不斷努力地反覆進行檢討之結果,找到了一種創見,就是:因應於上部磁極6的直流靜磁場的強度,確實存在著:適切的吐出方向的傾斜角度α。亦即,可以得知:如果由上部磁極6所施加的直流靜磁場的強度為1500Gs以上且未達2500Gs(高斯;1Gs=10-4T)的話,將浸漬式噴嘴4的吐出方向設定為:通過浸漬式噴嘴4的鉛直軸中心,並且相對於與鑄模長邊面平行的基準面,在下列的數式(3)的範圍內保持傾斜,而如果由上部磁極6所施加的直流靜磁場的強度為2500Gs以上且未達3500Gs的話,則是在下列的數式(4)的範圍內保持的話,係可獲得良質的鋼胚鑄片。這是因為:如果是直流靜磁場的強度係2500Gs以上且未達3500Gs之較強的情況下,藉由將傾斜角度α設定在如數式(4)所示的這樣的較大角度的話,就可對於熔鋼流賦予其與靜磁場所導致的制動效果相匹配的流速。 When such electromagnetic flow control is performed, the molten steel flow system is braked by the static magnetic field, so that the mold powder can be prevented from being caught. On the other hand, in order to suppress the bubbles and minute inclusions from being caught in the solidified cast piece casing 9, it is necessary to impart a moderate flow velocity to the molten steel flow. The inventors of the present invention have continuously strived to repeat the results of the review, and found a finding that, in response to the intensity of the DC static magnetic field of the upper magnetic pole 6, there is indeed an inclination angle α of the appropriate discharge direction. That is, it can be known that if the intensity of the DC static magnetic field applied by the upper magnetic pole 6 is 1500 Gs or more and less than 2500 Gs (Gauss; 1 Gs = 10 -4 T), the discharge direction of the immersion nozzle 4 is set to: By the center of the vertical axis of the immersion nozzle 4, and with respect to the reference plane parallel to the long side surface of the mold, the inclination is maintained in the range of the following formula (3), and if the DC static magnetic field is applied by the upper magnetic pole 6, When the strength is 2,500 Gs or more and less than 3,500 Gs, if it is maintained within the range of the following formula (4), a good steel slab can be obtained. This is because if the intensity of the DC static magnetic field is 2500 Gs or more and the strength is less than 3500 Gs, by setting the inclination angle α to such a large angle as shown in the formula (4), The flow rate at which the molten steel flow is matched to the braking effect caused by the static magnetic field.
θ≦α≦θ+5...數式(3) ≦≦α≦θ+5. . . Equation (3)
θ+6≦α≦θ+10...數式(4) θ+6≦α≦θ+10. . . Equation (4)
第6圖係與前述不同之別種連續鑄造用鑄模的概略剖 面圖。又,第7圖係由鉛直上方來觀看第6圖時的概略剖面圖。鋼胚鑄片用的連續鑄造用鑄模40,係對於第1圖所示的連續鑄造用鑄模20,在鑄模長邊2的背面,又設置了:隔介著鑄模長邊2而相對向的一對直線型移動磁場發生裝置42。直線型移動磁場發生裝置42的磁場的移動方向是沿著鑄模寬度方向。對於從設置在鑄模內的浸漬式噴嘴4所吐出的吐出流11賦予制動力,來控制鑄模內流動的情況下,係如第7圖(a)所示般地,係朝向:從鑄模短邊3往浸漬式噴嘴4的方向施加移動磁場;對於吐出流11賦予加速力,來控制鑄模內流動的情況下,則是如第7圖(b)所示般地,係朝向:從浸漬式噴嘴4往鑄模短邊3的方向施加移動磁場。可知這種流動控制方式的特徵係為:對於吐出流11賦予制動力或者加速力,而能夠將吐出流11隨時都控制在合宜的狀態,但基本上係形成以浸漬式噴嘴4為中心之左右對稱的熔鋼流,因此,在左右的熔鋼流互相干擾的部分,將會產生流速很小的領域。本發明人等,也找到了一種創見,就是:即使是在這種情況下,也是可以藉由將浸漬式噴嘴4的吐出方向之相對於基準面的傾斜角度α控制在適切的值,來抑制氣泡和微小夾雜物被捕捉在凝固鑄片外殼9中。經過各種的實驗和調查的結果得知:在施加這種移動磁場的鑄模內流動控制方式的情況下,藉由將浸漬式噴嘴4的吐出方向設定為:通過浸漬式噴嘴的鉛直軸中心,並且相對於與鑄模長邊面平行的基準面,在下列的數式(5)的範圍內保持傾斜的話,即 可獲得良質的鋼胚鑄片。 Fig. 6 is a schematic cross-sectional view of a casting mold for continuous casting different from the above Surface map. In addition, Fig. 7 is a schematic cross-sectional view when the sixth figure is viewed from the upper side. The continuous casting mold 40 for a steel slab is the one for the continuous casting mold 20 shown in Fig. 1, and the opposite side of the long side 2 of the mold is provided on the back side of the long side 2 of the mold. The linear magnetic field generating device 42 is moved. The moving direction of the magnetic field of the linear moving magnetic field generating device 42 is along the width direction of the mold. When the braking force is applied to the discharge flow 11 discharged from the immersion nozzle 4 provided in the mold to control the flow in the mold, as shown in Fig. 7(a), the orientation is from the short side of the mold. 3, a moving magnetic field is applied in the direction of the immersion nozzle 4; when an acceleration force is applied to the discharge flow 11 to control the flow in the mold, as shown in Fig. 7(b), the direction is: from the immersion nozzle 4 A moving magnetic field is applied in the direction of the short side 3 of the mold. It is understood that the flow control method is characterized in that the discharge flow 11 is given a braking force or an acceleration force, and the discharge flow 11 can be controlled in a convenient state at any time, but basically the center of the immersion nozzle 4 is formed. The symmetrical molten steel flow, therefore, in the portion where the left and right molten steel flows interfere with each other, an area where the flow velocity is small will occur. The present inventors have also found a finding that even in this case, it is possible to suppress the inclination angle α of the discharge direction of the immersion nozzle 4 with respect to the reference surface to an appropriate value. Air bubbles and minute inclusions are trapped in the solidified cast piece casing 9. As a result of various experiments and investigations, it is known that, in the case of the flow control method in the mold to which the moving magnetic field is applied, the discharge direction of the immersion nozzle 4 is set to be the center of the vertical axis passing through the immersion nozzle, and When it is inclined in the range of the following formula (5) with respect to the reference plane parallel to the long side surface of the mold, A good quality steel slab can be obtained.
θ+2≦α≦θ+7...數式(5) θ+2≦α≦θ+7. . . Equation (5)
亦即,被認為是:即使對於很容易形成左右對稱的鑄模內的熔鋼流,只要將浸漬式噴嘴的吐出方向朝向數式(5)所示的傾斜角度的話,亦可對於熔鋼流賦予適度的流速。 In other words, it is considered that even if it is easy to form a molten steel flow in a bilaterally symmetrical mold, if the discharge direction of the immersion nozzle is directed to the inclination angle shown by the formula (5), the molten steel flow can be imparted. Moderate flow rate.
第8圖係與前述不同之別種連續鑄造用鑄模的概略剖面圖。又,第9圖係由鉛直上方觀看第8圖時的概略剖面圖。在連續鑄造用鑄模50上,係對於第1圖所示的連續鑄造用鑄模20,係在鑄模長邊2的背面,又設置了:隔介著鑄模長邊2而相對向之一對磁極52。在磁極52,係如第9圖所示般地,設置有:可施加交流移動磁場的交流移動磁場發生線圈12。磁極52係施加磁場的移動方向係沿著鑄模寬度方向的交流移動磁場,並且對於鑄模內的熔鋼8賦予水平方向上的迴旋流來控制熔鋼流的流動。在這種流動控制手法中,係舉出:將來自浸漬式噴嘴4的吐出方向設定成:在鑄模短邊3的方向上呈左右對稱地吐出的情況的例子,來說明鑄模內的熔鋼流的流動。 Fig. 8 is a schematic cross-sectional view showing a mold for continuous casting which is different from the above. Further, Fig. 9 is a schematic cross-sectional view when the eighth figure is viewed from the upper side. In the continuous casting mold 50, the continuous casting mold 20 shown in Fig. 1 is placed on the back surface of the long side 2 of the mold, and is provided with a pair of magnetic poles 52 opposed to each other via the long side 2 of the mold. . In the magnetic pole 52, as shown in Fig. 9, an AC moving magnetic field generating coil 12 to which an AC moving magnetic field can be applied is provided. The magnetic pole 52 is moved in a direction in which the magnetic field is applied, and is a moving magnetic field in the width direction of the mold, and a swirling flow in the horizontal direction is given to the molten steel 8 in the mold to control the flow of the molten steel flow. In the flow control method, the discharge direction from the immersion nozzle 4 is set to be symmetrical in the direction of the short side 3 of the mold, and the molten steel flow in the mold is explained. The flow.
第10圖係顯示將吐出方向設定成垂直於鑄模短邊的鑄造條件下之鑄模內的熔鋼流速狀況的示意圖。在第10圖中,元件符號15係表示:由交流移動磁場所形成的鑄模內熔鋼湯面10以及在其附近之朝向順時針方向或逆時針方向進行單一方向旋轉的迴旋流;16係表示:吐 出流11衝撞鑄模短邊3側的凝固鑄片外殼9之後,朝向鉛直上方流動,然後,在鑄模內熔鋼湯面10從鑄模短邊側朝向浸漬式噴嘴側流動的反轉流;17係表示:低流速領域;18係表示:因為迴旋流15與反轉流16撞擊而發生的渦流;19係表示:吐出流11撞擊鑄模短邊側的凝固鑄片外殼之後,朝向鉛直下方流動的下降流。此外,在第10圖中,雖然只在其中一側的鑄模短邊側,標示出低流速領域17以及渦流18,但是,在另一側的鑄模短邊側也會發生低流速領域17以及渦流18。而且已經確認出如第10圖所示的,在交流移動磁場所造成的迴旋流15的下游領域之鑄模長邊2的寬度方向之鑄模短邊3的旁邊,會發生熔鋼流速很小之低流速領域17。從根據這種鑄造條件下的連續鑄造機所鑄造的鋼製品,進行缺陷分布的調查結果,可以確認出:鋼製品的缺陷所存在的領域,係與低流速領域17的發生位置一致。 Fig. 10 is a view showing the flow rate of the molten steel in the casting mold under the casting conditions in which the discharge direction is set to be perpendicular to the short side of the mold. In Fig. 10, reference numeral 15 denotes a molten steel noodle soup 10 formed by an alternating magnetic field and a swirling flow in a single direction in a clockwise or counterclockwise direction in the vicinity thereof; :threw up The outflow 11 collides with the solidified cast piece casing 9 on the short side 3 side of the mold, and then flows vertically upward, and then, in the mold, the molten steel noodle 10 flows from the short side of the mold toward the impregnation nozzle side; Indicates: low flow velocity field; 18 series indicates: eddy current due to the impact of the swirling flow 15 and the reverse flow 16; 19 indicates that the discharge flow 11 hits the solidified cast piece shell on the short side of the mold, and then flows downward toward the vertical flow. flow. Further, in Fig. 10, although the low flow velocity region 17 and the eddy current 18 are indicated on only the short side of the mold on one side, the low flow velocity region 17 and the eddy current also occur on the short side of the mold on the other side. 18. Further, it has been confirmed that, as shown in Fig. 10, the flow rate of the molten steel is extremely low next to the short side 3 of the mold in the width direction of the long side 2 of the mold in the downstream region of the swirling flow 15 caused by the alternating moving magnetic field. Flow rate field 17. From the results of the investigation of the defect distribution of the steel product cast by the continuous casting machine under such casting conditions, it was confirmed that the field in which the defects of the steel product existed coincides with the occurrence position of the low flow velocity field 17.
此外,本發明人等,經過各種的考察之結果,找到一種創見,就是:在鑄模短邊3的旁邊,會有:因交流移動磁場所造成的迴旋流15又與吐出流11撞擊短邊側凝固鑄片外殼9所造成的反轉流16進行撞擊和干擾而產生低流速領域17,氣泡和夾雜物等被捕捉於這個低流速領域17中,因而成為最終的鋼製品的缺陷。而且,也找到了一種創見,就是:因迴旋流15與反轉流16進行衝撞,而造成渦流18,鑄模粉被這種渦流18捲入而被捕捉在凝固鑄片外殼9內,這種鑄模粉也有可能成為鋼製品 的缺陷。本發明人等,乃針對於這些問題的解決對策不斷努力地檢討。如前所述,起因於夾雜物、氣泡、鑄模粉被捕捉而產生的鋼製品的缺陷,係因為:交流移動磁場所造成的迴旋流15與吐出流11的反轉流16進行衝撞和干擾而形成低流速領域17以及產生渦流18所導致的。因此,本發明人等,找到了一種創見,就是:即使是在施加交流移動磁場來造成水平方向上的迴旋流15的流動控制方式中,只要將浸漬式噴嘴4的吐出方向設定成:相對於基準面保持傾斜的話,就可以避免迴旋流15與反轉流16進行衝撞和干擾。 Further, the inventors of the present invention, after various investigations, found a finding that, beside the short side 3 of the mold, there will be: the swirling flow 15 caused by the alternating magnetic field and the short side of the spouting stream 11 The reverse flow 16 caused by the solidified cast piece casing 9 strikes and interferes to produce a low flow velocity field 17, in which bubbles and inclusions are trapped, thereby becoming a defect in the final steel product. Moreover, a concept has also been found in which the swirling flow 15 collides with the reverse flow 16 to cause the eddy current 18, and the mold powder is caught by the eddy current 18 and captured in the solidified cast piece casing 9, which is molded. Powder may also become a steel product Defects. The present inventors have continuously reviewed the solutions to these problems. As described above, the defects of the steel product resulting from the inclusion of inclusions, bubbles, and mold powder are caused by the collision and interference of the swirling flow 15 caused by the alternating magnetic field and the reverse flow 16 of the discharge stream 11. The low flow rate field 17 is formed and the eddy current 18 is generated. Therefore, the present inventors have found a finding that even in the flow control mode in which the alternating magnetic field is applied to cause the swirling flow 15 in the horizontal direction, the discharge direction of the dipping nozzle 4 is set to be: If the reference surface is kept inclined, it is possible to prevent the swirling flow 15 from colliding and disturbing with the reverse flow 16.
第11圖係由鉛直上方來觀看將吐出方向保持傾斜來進行鑄造時的樣子之概略圖。經過各種的流動調查實驗得知:如第11圖所示般地,將浸漬式噴嘴4的吐出方向設定成:朝向由交流移動磁場所造成的迴旋流15的上游側保持傾斜的作法是很重要的。此外,本發明人等,在進行過流動調查實驗之後得知:將交流移動磁場的強度設定在300~1000Gs的範圍內,並且在交流移動磁場的強度X(Gs)與被連續鑄造的鋼胚鑄片的寬度W(mm)之比值X/W(Gs/mm)係為0.30以上且未達0.45的情況下,將浸漬式噴嘴4的吐出方向設定成:通過浸漬式噴嘴4的鉛直軸中心,並且相對於與鑄模長邊面平行的基準面,朝向由交流移動磁場所形成的迴旋流的上游側,在下列數式(6)的範圍內呈傾斜;在交流移動磁場的強度X(Gs)與被連續鑄造鋼胚鑄片的寬度W(mm)之比值X/W(Gs/mm)係為0.45 以上且未達0.55的情況下,將浸漬式噴嘴4的吐出方向設定成:通過浸漬式噴嘴4的鉛直軸中心,並且相對於與鑄模長邊面平行的基準面,朝向由交流移動磁場所形成的迴旋流的上游側,在下列數式(7)的範圍內呈傾斜的話,係可獲得良質的鋼胚鑄片。 Fig. 11 is a schematic view showing a state in which the direction in which the discharge direction is kept inclined and the casting is performed from the vertical upper side. According to various flow investigation experiments, it is known that, as shown in Fig. 11, the discharge direction of the immersion nozzle 4 is set such that it is important to keep the inclination toward the upstream side of the swirling flow 15 caused by the alternating magnetic field. of. Further, the inventors of the present invention have learned from the flow investigation experiment that the intensity of the alternating magnetic field is set in the range of 300 to 1000 Gs, and the intensity X (Gs) of the alternating magnetic field and the continuously cast steel embryo. When the ratio X/W (Gs/mm) of the width W (mm) of the slab is 0.30 or more and less than 0.45, the discharge direction of the immersion nozzle 4 is set to pass through the center of the vertical axis of the immersion nozzle 4. And with respect to the reference plane parallel to the long side surface of the mold, toward the upstream side of the swirling flow formed by the alternating magnetic field, is inclined in the range of the following formula (6); the intensity X of the moving magnetic field in the alternating current (Gs The ratio of the width W (mm) of the continuously cast steel slab is X/W (Gs/mm) is 0.45. When the above is less than 0.55, the discharge direction of the immersion nozzle 4 is set so as to pass through the center of the vertical axis of the immersion nozzle 4, and is formed toward the magnetic field by the alternating current with respect to the reference plane parallel to the long side surface of the mold. On the upstream side of the swirling flow, if it is inclined within the range of the following formula (7), a good steel blank cast piece can be obtained.
θ-3≦α≦θ...數式(6) Θ-3≦α≦θ. . . Number (6)
θ-6≦α≦θ-4...數式(7) ≦-6≦α≦θ-4. . . Equation (7)
對於第4圖所示的熔鋼8施加直流靜磁場的情況下,以及對於第6圖所示的吐出流11賦予制動力或加速力的情況下,基本上,鑄模內的熔鋼流都是呈左右對稱,因此,為了賦予適度的迴旋流速,係將浸漬式噴嘴4的吐出方向設定成:朝鑄模長邊2側做大幅度的傾斜為宜。另一方面,利用第8圖所示的電磁流動控制來賦予迴旋流攪拌的情況下,只要傾斜的角度是足以抑制反轉流16與迴旋流15發生衝撞和干繞的程度的話就可以,因此,採用數式(6)以及數式(7)所示般的較小的傾斜角度α為宜。此外,傾斜角度α太大的話,凝固鑄片外殼9旁邊的熔鋼的流速將會太快,會阻礙凝固鑄片外殼9的成長,會有引發鑄漏(Break out)之類的作業障礙之虞慮,因此並不合宜。 When a DC static magnetic field is applied to the molten steel 8 shown in Fig. 4, and when a braking force or an acceleration force is applied to the discharge flow 11 shown in Fig. 6, basically, the molten steel flow in the mold is Since it is symmetrical to the left and right, in order to provide an appropriate swirling flow rate, the discharge direction of the immersion nozzle 4 is preferably set to a large inclination toward the long side 2 side of the mold. On the other hand, in the case where the swirling flow agitation is given by the electromagnetic flow control shown in Fig. 8, the angle of inclination is sufficient to suppress the collision and dry winding of the reverse flow 16 and the swirling flow 15, so It is preferable to use a small inclination angle α as shown in the formula (6) and the formula (7). Further, if the inclination angle α is too large, the flow rate of the molten steel beside the solidified cast piece casing 9 will be too fast, which will hinder the growth of the solidified cast piece casing 9, and may cause operational troubles such as causing a blow out. It is not appropriate, therefore.
第12圖係與前述不同之別種連續鑄造用鑄模1之概略剖面圖,元件符號1係表示:連續鑄造用鑄模;2係表示:鑄模長邊;3係表示:鑄模短邊;4係表示:浸漬式噴嘴;5係表示:浸漬式噴嘴的吐出孔;6係表示:上部磁極;7係表示:下部磁極;8係表示:熔鋼;9 係表示:凝固鑄片外殼;10係表示:鑄模內熔鋼湯面;11係表示:來自浸漬式噴嘴的吐出流。 Fig. 12 is a schematic cross-sectional view showing a mold 1 for continuous casting different from the above, and the symbol 1 indicates: a mold for continuous casting; 2 indicates a long side of the mold; 3 indicates a short side of the mold; and 4 indicates: Immersion nozzle; 5 series means: discharge hole of the immersion nozzle; 6 series means: upper magnetic pole; 7 series means: lower magnetic pole; 8 series means: molten steel; It means: solidified cast piece outer casing; 10 series means: molten steel noodle soup in the mold; 11 series shows: discharge flow from the immersion nozzle.
連續鑄造用鑄模1係由:相對向的一對鑄模長邊2、相對向的一對鑄模短邊3組合而構成的,在由一對鑄模長邊2與一對鑄模短邊3所圍繞的鑄模內部空間,配置有浸漬式噴嘴4,從浸漬式噴嘴4的吐出孔5將熔鋼8注入鑄模內部空間,來進行熔鋼8的連續鑄造。吐出孔5係相對於通過浸漬式噴嘴4的中心的直線呈左右對稱地配置在浸漬式噴嘴4的側壁,由吐出孔5所注入的熔鋼8將成為吐出流11而朝向左右的鑄模短邊3的方向吐出。被注入到鑄模內部空間的熔鋼8將會與鑄模長邊2及鑄模短邊3接觸而受到冷卻,在與鑄模長邊2及鑄模短邊3的接觸面將會形成凝固鑄片外殼9,以這個凝固鑄片外殼9為外殻,而其內部是尚未凝固的熔鋼8的鋼胚則是被連續性地朝下方抽拉,而被製成鋼胚鑄片。此時,係在鑄模內的熔鋼湯面10上添加可發揮潤滑劑、保溫劑、氧化防止劑等的功能之鑄模粉(未圖示)。 The continuous casting mold 1 is composed of a pair of opposed mold long sides 2 and a pair of opposed mold short sides 3, and is surrounded by a pair of mold long sides 2 and a pair of mold short sides 3. In the inner space of the mold, the immersion nozzle 4 is disposed, and the molten steel 8 is injected into the inner space of the mold from the discharge hole 5 of the immersion nozzle 4 to carry out continuous casting of the molten steel 8. The discharge hole 5 is disposed on the side wall of the immersion nozzle 4 in a bilaterally symmetrical manner with respect to a straight line passing through the center of the immersion nozzle 4, and the molten steel 8 injected from the discharge hole 5 becomes the discharge flow 11 and faces the right and left sides of the mold. Spit in the direction of 3. The molten steel 8 injected into the inner space of the mold will be cooled by contact with the long side 2 of the mold and the short side 3 of the mold, and a solidified cast shell 9 will be formed at the contact surface with the long side 2 of the mold and the short side 3 of the mold. The solidified cast piece casing 9 is an outer casing, and the steel blank in which the inside of the molten steel 8 which has not been solidified is continuously drawn downward, and is formed into a steel blank cast piece. At this time, a mold powder (not shown) which functions as a lubricant, a heat retaining agent, an oxidation inhibitor, or the like is added to the molten steel noodle soup 10 in the mold.
第13圖係第12圖的上部磁極的部位之概略橫剖面圖。又,第14圖係第12圖的下部磁極的部位之概略橫剖面圖。本實施方式所使用的連續鑄造用鑄模1,係在鑄模長邊2的背面,配置有:隔介著鑄模長邊2而相對向的一對上部磁極6與一對下部磁極7。在上部磁極6係如第13圖所示般地,設置有:用來施加交流移動磁場的交流移動磁場發生線圈12、以及用來施加直流靜磁場的 直流靜磁場發生線圈13;另一方面,在下部磁極7係如第14圖所示般地,設置有:用來施加直流靜磁場的直流靜磁場發生線圈14。交流移動磁場發生線圈12、直流靜磁場發生線圈13以及直流靜磁場發生線圈14的配置長度,係與被鑄造的鋼胚鑄片的寬度同等程度或者更大。 Fig. 13 is a schematic cross-sectional view showing a portion of the upper magnetic pole of Fig. 12. Further, Fig. 14 is a schematic cross-sectional view showing a portion of the lower magnetic pole of Fig. 12; The continuous casting mold 1 used in the present embodiment is disposed on the back surface of the long side 2 of the mold, and is disposed with a pair of upper magnetic poles 6 and a pair of lower magnetic poles 7 opposed to each other via the long side 2 of the mold. The upper magnetic pole 6 is provided with an alternating current moving magnetic field generating coil 12 for applying an alternating current moving magnetic field and for applying a direct current static magnetic field as shown in FIG. The DC static magnetic field generating coil 13 is provided. On the other hand, as shown in Fig. 14, the lower magnetic pole 7 is provided with a DC static magnetic field generating coil 14 for applying a DC static magnetic field. The arrangement length of the AC moving magnetic field generating coil 12, the DC static magnetic field generating coil 13, and the DC static magnetic field generating coil 14 is equal to or greater than the width of the cast steel blank cast piece.
根據由上部磁極6的交流移動磁場發生線圈12所施加的交流移動磁場,鑄模內熔鋼將會形成朝水平方向旋轉之熔鋼8的迴旋流,而且,根據由上部磁極6的直流靜磁場發生線圈13所施加的直流靜磁場,鑄模內的熔鋼湯面10的熔鋼流將會受到制動(減速)。同樣地,根據由下部磁極7的直流靜磁場發生線圈14所施加的直流靜磁場,吐出流11之中的朝向下方之正要通過直流靜磁場發生線圈14的位置的熔鋼流將會受到制動(減速)。此外,浸漬式噴嘴4的吐出孔5係設置在:「由上部磁極6所施加的直流靜磁場之最大值的位置」與「由下部磁極7所施加的直流靜磁場之最大值的位置」之間。 According to the alternating current moving magnetic field applied by the alternating magnetic field generating coil 12 of the upper magnetic pole 6, the molten steel in the mold will form a swirling flow of the molten steel 8 which is rotated in the horizontal direction, and, depending on the direct current static magnetic field generated by the upper magnetic pole 6, The DC static magnetic field applied by the coil 13 will be braked (decelerated) by the molten steel flow of the molten steel noodle 10 in the mold. Similarly, according to the DC static magnetic field applied by the DC static magnetic field generating coil 14 of the lower magnetic pole 7, the molten steel flow which is directed downward through the position of the DC static magnetic field generating coil 14 in the discharge flow 11 will be braked. (slow down). Further, the discharge hole 5 of the immersion nozzle 4 is provided at "the position of the maximum value of the DC static magnetic field applied by the upper magnetic pole 6" and "the position of the maximum value of the DC static magnetic field applied by the lower magnetic pole 7". between.
第15圖係將來自浸漬式噴嘴的吐出方向設定成垂直於鑄模短邊的鑄造條件下之鑄模內的熔鋼流速狀況的示意圖。本發明人等,使用第12圖所示的連續鑄造用鑄模1,對於上部磁極6重疊地施加直流靜磁場與交流移動磁場,對於下部磁極7則是施加直流靜磁場,並且針對於:將來自浸漬式噴嘴4的吐出孔5的吐出方向設定成與鑄模長邊面平行,並且吐出流11是垂直地朝向鑄模短邊3的鑄造條件下的鑄模內的流動狀況進行了調查。 Fig. 15 is a view showing the flow direction of the molten steel in the mold under the casting condition perpendicular to the short side of the mold, with the discharge direction from the immersion nozzle being set. The present inventors have used the continuous casting mold 1 shown in Fig. 12 to apply a DC static magnetic field and an AC moving magnetic field to the upper magnetic pole 6, and to apply a DC static magnetic field to the lower magnetic pole 7, and to: The discharge direction of the discharge hole 5 of the immersion nozzle 4 was set to be parallel to the long side surface of the mold, and the flow state of the discharge flow 11 in the mold under the casting condition perpendicularly to the short side 3 of the mold was investigated.
將這種鑄造條件下之鑄模內的流速分布,藉由數值計算和使用了低融點合金(Bi-Pb-Sn-Cd合金;融點約70℃)的實際機器之1/4尺寸的試驗鑄造裝置所進行的流速測定,反覆進行了確認。其結果,係確認出:如第15圖所示般地,在交流移動磁場所造成的迴旋流15的下流領域,也就是在鑄模長邊2的寬度方向上的鑄模短邊3的旁邊,產生了熔鋼流速變小的低流速領域17。在第15圖中,元件符號15係表示:由交流移動磁場所形成的在鑄模內熔鋼湯面10及其近旁朝順時鐘方向或逆時鐘方向的單一方向進行旋轉的迴旋流;16係表示:吐出流11衝撞鑄模短邊側的凝固鑄片外殼之後,朝鉛直上方流動,然後,在鑄模內熔鋼湯面10從鑄模短邊側朝向浸漬式噴嘴側流動之反轉流;17係表示:低流速領域;18係表示:因為迴旋流15與反轉流16衝撞所產生的渦流;19係表示:吐出流11衝撞鑄模短邊側的凝固鑄片外殼之後,朝鉛直下方流動的下降流。此外,在第15圖中雖然只在其中一側的鑄模短邊側標示出低流速領域17及渦流18,氮是在另一側的鑄模短邊側也會產生低流速領域17及渦流18。 The flow velocity distribution in the mold under such casting conditions was calculated by numerical calculation and a quarter-size test of an actual machine using a low melting point alloy (Bi-Pb-Sn-Cd alloy; melting point about 70 ° C) The flow rate measurement by the casting apparatus was repeatedly confirmed. As a result, it was confirmed that, as shown in Fig. 15, the downstream flow region of the swirling flow 15 caused by the alternating magnetic field, that is, the short side 3 of the mold in the width direction of the long side 2 of the mold was produced. The flow rate of the molten steel becomes smaller in the low flow rate field 17 . In Fig. 15, reference numeral 15 denotes a swirling flow which is formed by an alternating current moving magnetic field and which is rotated in a single direction of the molten steel noodle soup 10 in the mold and its vicinity in the clockwise direction or the counterclockwise direction; : The discharge flow 11 collides with the solidified cast piece shell on the short side of the mold, and then flows vertically upward, and then, in the mold, the molten steel noodle 10 flows from the short side of the mold toward the impregnation nozzle side; : low flow rate field; 18 series means: eddy current generated by the swirling flow 15 colliding with the reverse flow 16; 19 is a downward flow flowing downwardly directly after the discharge flow 11 collides with the solidified cast piece shell on the short side of the mold. . Further, in Fig. 15, although the low flow velocity region 17 and the eddy current 18 are indicated on only the short side of the mold on one side, the nitrogen flow field 17 and the eddy current 18 are generated on the short side of the mold on the other side.
此外,從在這種鑄造條件下的實際機器的連續鑄造機所鑄造的鋼製品的缺陷分布的調查結果,也確認出:鋼製品之缺陷所存在的領域係與上述的低流速領域17的發生位置一致。 In addition, from the investigation results of the defect distribution of the steel product cast by the continuous casting machine of the actual machine under such casting conditions, it was also confirmed that the field in which the defect of the steel product exists and the occurrence of the low flow rate field 17 described above The position is the same.
本發明人等,經過了各種考察之結果,找到 了一種創見,就是:在鑄模短邊的近旁,由交流移動磁場所造成的迴旋流15與來自吐出孔5的吐出流11衝撞短邊凝固鑄片外殼之後所造成的反轉流16,因為這兩種流動的互相衝撞和干擾而產生了低流速領域17,氣泡和夾雜物等被捕捉到這種低流速領域17內,而成為最終鋼製品的缺陷。此外,也找到了一種創見,就是:迴旋流15與反轉流16衝撞將會產生渦流18,鑄模粉被捲入到這種渦流18而被凝固鑄片外殼所捕捉,這個也有可能成為鋼製品的缺陷。 The inventors, etc., after various investigations, found A novelty is that, in the vicinity of the short side of the mold, the swirling flow 15 caused by the alternating magnetic field and the discharge flow 11 from the discharge hole 5 collide with the reverse flow 16 caused by the short-side solidified cast shell, because this The two flows collide and interfere with each other to create a low velocity field 17 where bubbles and inclusions are trapped into this low velocity field 17 and become a defect in the final steel product. In addition, a finding has been found that the swirling flow 15 and the reverse flow 16 collide to generate a vortex 18, and the mold powder is drawn into the vortex 18 and captured by the solidified cast shell, which may also become a steel product. Defects.
本發明人等,針對於這些問題的解決對策不斷地努力檢討。如前所述,起因於夾雜物、氣泡、鑄模粉受到捕捉而導致的鋼製品的缺陷係因為:交流移動磁場所造成的迴旋流15與來自吐出孔5的吐出流11的反轉流16進行衝撞和干擾所產生的低流速領域17及渦流18所引起的。因此,本發明人等,乃針對於如何能夠避免:迴旋流15與反轉流16進行衝撞和干繞的方法加以檢討,其結果,找到了一種創見,就是:將來自浸漬式噴嘴4的吐出流11的吐出方向,從與鑄模短邊3垂直的方向上錯開。 The inventors of the present invention constantly strive to review the solutions to these problems. As described above, the defects of the steel product caused by inclusions, bubbles, and mold powder are caused by the reverse flow 16 of the swirling flow 15 caused by the AC moving magnetic field and the discharge flow 11 from the discharge hole 5. The low velocity fields 17 and eddy currents 18 caused by collisions and disturbances are caused. Therefore, the inventors of the present invention have focused on how to avoid the method in which the swirling flow 15 and the reverse flow 16 collide and dry, and as a result, find a finding that the discharge from the dipping nozzle 4 is performed. The discharge direction of the flow 11 is shifted from the direction perpendicular to the short side 3 of the mold.
通常,浸漬式噴嘴4的吐出孔5大多是以將熔鋼8朝向鑄模短邊面吐出的方式,被配置成:朝向與鑄模長邊面平行的方向,而且被刻意設置成:保持鑄模內左右的熔鋼流動的對稱性。但是,在本發明的這種利用交流移動磁場來對於鑄模內的熔鋼8賦予迴旋流15的條件 下,被認為是:與其要保持鑄模內左右的對稱性的作法,倒不如以考慮到以浸漬式噴嘴4為中心的軸對稱性,來決定浸漬式噴嘴4的吐出孔5的吐出方向的作法,在原理上更為合適。 In general, the discharge hole 5 of the immersion nozzle 4 is often disposed so as to be discharged toward the short side surface of the mold, and is disposed in a direction parallel to the long side surface of the mold, and is intentionally provided to keep the inside and outside of the mold. The symmetry of the molten steel flow. However, the condition for imparting the swirling flow 15 to the molten steel 8 in the mold by the alternating moving magnetic field of the present invention is employed. In the following, it is considered that the symmetry of the left and right sides of the mold is maintained, and the discharge direction of the discharge port 5 of the immersion nozzle 4 is determined in consideration of the axis symmetry centering on the immersion nozzle 4 . In principle, it is more appropriate.
第16圖係從鉛直上方來觀看將浸漬式噴嘴的吐出方向朝向迴旋流的上游側傾斜來進行鑄造的樣子之概略圖。根據數值解析和使用低融點合金的試驗鑄造裝置,以各種條件,針對於來自浸漬式噴嘴4的吐出方向加以檢討之結果,找到了一種創見,就是:將上部磁極6的交流移動磁場的強度設定在500~900(Gs)的範圍內,將上部磁極6的直流靜磁場的強度設定在2000~3300(Gs)的範圍內,將下部磁極7的直流靜磁場的強度設定在3000~4500(Gs)的範圍內,並且將上部磁極6的交流移動磁場強度X(Gs)與被連續鑄造的鋼胚鑄片的寬度W(mm)之比值X/W(Gs/mm)予以控制在0.30以上且未達0.55的情況下,係如第16圖所示般地,將浸漬式噴嘴4的吐出方向設定成:朝向被交流移動磁場所形成的迴旋流15的上游側傾斜,可避免迴旋流15與反轉流16的衝撞和干擾,不會產生低流速領域17以及渦流18,而可獲得所期望的鑄模內熔鋼流動。 Fig. 16 is a schematic view showing a state in which the discharge direction of the immersion nozzle is inclined toward the upstream side of the swirling flow as viewed from the upper side. According to the numerical analysis and the test casting apparatus using the low-melting alloy, the results of reviewing the discharge direction from the immersion nozzle 4 under various conditions have found a novelty that the intensity of the alternating magnetic field of the upper magnetic pole 6 is moved. Set the range of 500 to 900 (Gs), set the intensity of the DC static magnetic field of the upper magnetic pole 6 to the range of 2000 to 3300 (Gs), and set the intensity of the DC static magnetic field of the lower magnetic pole 7 to 3000 to 4500. Within the range of Gs), the ratio X/W (Gs/mm) of the AC moving magnetic field strength X (Gs) of the upper magnetic pole 6 to the width W (mm) of the continuously cast steel blank is controlled to be 0.30 or more. When it is less than 0.55, as shown in Fig. 16, the discharge direction of the immersion nozzle 4 is set so as to be inclined toward the upstream side of the swirling flow 15 formed by the alternating magnetic field, and the swirling flow 15 can be avoided. The collision and interference with the reverse flow 16 does not produce the low velocity field 17 and the vortex 18, and the desired molten steel flow in the mold can be obtained.
此外,X/W的比值若未達0.30的話,相對於鋼胚鑄片的寬度之迴旋流15的流速太小,因此即使將浸漬式噴嘴4的吐出方向保持傾斜也是無法獲得充分的效果。此外,也被認為是:X/W的比值若是0.55以上的 話,係可確保相對於鋼胚鑄片的寬度之充分的迴旋流15的流速,而可抑制因為與反轉流16的衝撞所產生的低流速領域17等的弊端,因此,將浸漬式噴嘴4的吐出方向設成傾斜所獲得的效果將會變小。又,如果將X/W的比值過度提高的話,迴旋流15變得太強,會捲入鑄模粉,因而會有發生由被捲入的鑄模粉所引起的缺陷之可能,因此並不合宜。此外,也被認為:在迴旋流15的流速充分夠快的情況下,若將吐出方向傾斜的話,迴旋流15將會變得太強,導致凝固鑄片外殼9的厚度變薄,而會有發生鑄漏現象之類的阻礙作業穩定性的原因之可能,因此並不合宜。 Further, if the ratio of X/W is less than 0.30, the flow velocity of the swirling flow 15 with respect to the width of the steel slab is too small, so that a sufficient effect cannot be obtained even if the discharge direction of the immersion nozzle 4 is kept inclined. In addition, it is also considered to be: if the ratio of X/W is 0.55 or more In this case, it is possible to ensure a sufficient flow velocity of the swirling flow 15 with respect to the width of the steel slab, and it is possible to suppress the disadvantages of the low flow velocity region 17 due to the collision with the reverse flow 16 and, therefore, the immersion nozzle The effect obtained by setting the discharge direction of 4 to be inclined will become smaller. Further, if the ratio of X/W is excessively increased, the swirling flow 15 becomes too strong, and the mold powder is entangled, so that defects due to the mold powder to be wound may occur, which is not preferable. Further, it is also considered that, in the case where the flow velocity of the swirling flow 15 is sufficiently fast enough, if the discharge direction is inclined, the swirling flow 15 will become too strong, resulting in a thinning of the thickness of the solidified cast piece casing 9, and there will be It is not appropriate to cause a cause such as a casting leakage phenomenon that hinders the stability of the operation.
此外,本發明人等,不斷反覆地進行檢討和實驗,著眼於交流移動磁場的強度X(Gs)與被鑄造的鋼胚鑄片的寬度W(mm)之比值X/W,因而找到了,最佳吐出方向的關係性。 In addition, the present inventors have continuously reviewed and experimented repeatedly, focusing on the ratio X/W of the intensity X (Gs) of the alternating moving magnetic field to the width W (mm) of the cast steel slab, and thus found that The relationship between the best spitting directions.
可得知:在交流移動磁場強度為X,與鑄片寬度W的比值X/W之(Gs/mm)為0.30以上且未達0.45的情況下,係將吐出方向設成:通過浸漬式噴嘴4的鉛直軸中心,且將相對於與鑄模長邊面平行的基準面之吐出方向的傾斜角度α,設定在下列的數式(8)的範圍內為宜。其原因被認為是:因為相對於鋼胚鑄片的寬度W之交流移動磁場強度X比較小,所以必須加大傾斜角度α,更積極的避免在迴旋流15的下流側的迴旋流15與反轉流16發生衝撞和干擾的緣故。 It can be seen that when the ratio of the alternating magnetic field strength X to the ratio X/W of the slab width W (Gs/mm) is 0.30 or more and less than 0.45, the discharge direction is set to: through the immersion nozzle It is preferable to set the inclination angle α of the discharge axis direction of the reference plane parallel to the long side surface of the mold to the center of the vertical axis of 4, and to set it within the range of the following formula (8). The reason for this is considered to be that since the AC moving magnetic field strength X with respect to the width W of the steel slab is relatively small, the inclination angle α must be increased, and the swirling flow 15 and the counter on the downstream side of the swirling flow 15 are more actively avoided. The flow 16 is subject to collision and interference.
θ-2≦α≦θ+5...數式(8) Θ-2≦α≦θ+5. . . Number (8)
又,也得知:在X/W的比值之(Gs/mm)為0.45以上且未達0.55的情況下,係將吐出方向設成:通過浸漬式噴嘴4的鉛直軸中心,且將相對於與鑄模長邊面平行的基準面之吐出方向的傾斜角度α,設定在下列的數式(9)的範圍內為宜。這是因為相對於鋼胚鑄片的寬度W之交流移動磁場強度X比較大,所以藉由將傾斜角度α設定成小一點來使吐出方向保持傾斜的話,既可避免在迴旋流15的下流側之迴旋流15與反轉流16發生衝撞和干擾,又可排除如上所述的鑄漏現象之類的阻礙作業穩定性的要因的風險的緣故。 Further, it is also known that when the ratio of X/W (Gs/mm) is 0.45 or more and less than 0.55, the discharge direction is set to pass through the center of the vertical axis of the immersion nozzle 4, and will be relative to The inclination angle α of the discharge direction of the reference surface parallel to the long side surface of the mold is preferably set within the range of the following formula (9). This is because the AC moving magnetic field intensity X with respect to the width W of the steel slab is relatively large. Therefore, by setting the inclination angle α to be small to keep the discharge direction inclined, the downstream side of the swirling flow 15 can be avoided. The swirling flow 15 collides with the reverse flow 16 and interferes with the risk of the stability of the work such as the casting leakage phenomenon as described above.
θ-5≦α≦θ+2...數式(9) Θ-5≦α≦θ+2. . . Number (9)
又,浸漬式噴嘴4的吐出方向的傾斜角度α,除了可以在連續鑄造開始之前就進行設定之外,亦可使用可變更吐出方向的傾斜角度α的裝置,在連續鑄造中來進行設定。使用該裝置在連續鑄造中,每當改變鑄模寬度等的鑄造條件時,就逐次地測定α和θ,以成為可符合數式(1)或從數式(3)至數式(9)所表示的α與θ的大小關係之傾斜角度α的方式,來變更浸漬式噴嘴4的吐出方向的話,可獲得更好的效果。 Further, the inclination angle α of the discharge direction of the immersion nozzle 4 can be set in the continuous casting, in addition to the setting before the start of continuous casting, or by using an apparatus that can change the inclination angle α of the discharge direction. In the continuous casting using the apparatus, each time the casting conditions such as the width of the mold are changed, α and θ are successively measured so as to be in accordance with the formula (1) or from the formula (3) to the formula (9). A better effect can be obtained by changing the discharge direction of the immersion nozzle 4 in such a manner that the inclination angle α of the magnitude relationship between α and θ is expressed.
第17圖係顯示進行變更吐出方向的傾斜角度α的處理之一例的流程圖。此處,使用第17圖來說明變 更浸漬式噴嘴4的吐出方向的傾斜角度α之處理。第17圖所示的處理,每隔預先設定的時間,就進行確認:浸漬式噴嘴4的浸漬深度為180mm以上且未達300mm,從吐出孔的水平方向朝下的熔鋼吐出角度為15~35°,在澆鑄槽流出孔與吐出孔之間吹入鈍氣的流量A(NL/min)與熔鋼吞吐量P(ton/min)之比值A/P是否落在2.0~3.5NL/ton的範圍內,如果符合該條件的話,就開始進行處理。又,該處理係可使用例如:專利文獻2所揭示的這種具備可變更吐出方向的驅動機構的裝置(以下,稱為「角度調整裝置」)來實施。在本實施方式中,係將角度調整裝置視為變更吐出方向的傾斜角度α的主體,來進行說明。 Fig. 17 is a flowchart showing an example of a process of changing the inclination angle α of the discharge direction. Here, use Figure 17 to illustrate the change The treatment of the inclination angle α of the discharge direction of the immersion nozzle 4 is further performed. The processing shown in Fig. 17 is confirmed every predetermined time: the immersion depth of the immersion nozzle 4 is 180 mm or more and less than 300 mm, and the molten steel discharge angle from the horizontal direction of the discharge hole is 15~ 35°, whether the ratio A/P of the flow rate A (NL/min) and the molten steel throughput P (ton/min) between the outflow hole and the discharge hole of the casting tank is between 2.0 and 3.5 NL/ton. Within the scope of this, if this condition is met, processing begins. In addition, the processing can be carried out using, for example, a device (hereinafter referred to as "angle adjustment device") having a drive mechanism capable of changing the discharge direction as disclosed in Patent Document 2. In the present embodiment, the angle adjustment device will be described as a main body that changes the inclination angle α of the discharge direction.
在第17圖所示的處理中,角度調整裝置係先判斷:連續鑄造裝置是否正處於定常的澆鑄中(步驟S101)。在本實施方式中,所稱的「定常的澆鑄中」,係指:「正在澆鑄中,既不是鑄造速度受到變更的狀態,也不是鑄模寬度受到變更的狀態,既不是鈍氣的流量受到變更的狀態,也不是浸漬式噴嘴4的浸漬深度受到變更的狀態」的狀態之意。 In the processing shown in Fig. 17, the angle adjusting means first judges whether or not the continuous casting apparatus is in the constant casting (step S101). In the present embodiment, the term "constant casting" means that "the casting speed is changed during the casting, and the mold width is not changed, and the flow rate of the blunt gas is not changed. The state of the immersion nozzle 4 is not changed in the state in which the immersion depth of the immersion nozzle 4 is changed.
角度調整裝置,若判斷出連續鑄造裝置並不是處於定常的澆鑄中的話(步驟S101:No),就結束第17圖所示的處理。角度調整裝置,係當連續鑄造裝置處於定常的澆鑄中的情況下(步驟S101:Yes),角度調整裝置才進行測定傾斜角度α與θ,並且判斷傾斜角度α是否符合數式(1)(步驟S102)。角度調整裝置,判斷出傾斜角度α 符合數式(1)的話(步驟S102:Yes),就結束第17圖所示的處理。另一方面,角度調整裝置若判斷出傾斜角度α不符合數式(1)的話(步驟S102:No),就再設定符合數式(1)的傾斜角度α(步驟S103)。角度調整裝置,就以可變成再設定的傾斜角度α的方式,來變更浸漬式噴嘴4的吐出方向(步驟S104),然後結束第17圖所示的處理。 When the angle adjusting device determines that the continuous casting device is not in the constant casting (step S101: No), the processing shown in Fig. 17 is ended. The angle adjusting device is configured such that when the continuous casting device is in a constant casting (step S101: Yes), the angle adjusting device performs the measurement of the inclination angles α and θ, and determines whether the inclination angle α conforms to the formula (1) (step S102). Angle adjustment device, determining the tilt angle α If the expression (1) is satisfied (step S102: Yes), the processing shown in Fig. 17 is ended. On the other hand, when the angle adjustment device determines that the inclination angle α does not satisfy the formula (1) (step S102: No), the inclination angle α conforming to the equation (1) is set again (step S103). The angle adjusting device changes the discharge direction of the immersion nozzle 4 so as to become the reset inclination angle α (step S104), and then ends the processing shown in Fig. 17.
以這種方式,角度調整裝置係藉由第17圖所示的處理,每隔預先設定的時間,就以可使得傾斜角度α符合數式(1)的方式,來變更浸漬式噴嘴4的吐出方向。如此一來,即使有某些不明的原因,導致傾斜角度α變成不再符合數式(1)的情況下,亦可利用角度調整裝置來變更浸漬式噴嘴4的吐出方向,以謀求傾斜角度α可符合數式(1)的關係,因此,可防止連續地製造出含有夾雜物的鋼胚鑄片。 In this manner, the angle adjusting device changes the discharge of the immersion nozzle 4 so that the inclination angle α conforms to the formula (1) every predetermined time by the processing shown in FIG. direction. In this way, even if there is some unknown reason that the inclination angle α becomes no longer in accordance with the formula (1), the discharge direction of the immersion nozzle 4 can be changed by the angle adjusting device to achieve the inclination angle α. The relationship of the formula (1) can be satisfied, and therefore, it is possible to prevent the steel slab containing inclusions from being continuously produced.
第18圖係顯示與前述不同的例子的流程圖。使用第18圖來說明變更浸漬式噴嘴4的吐出方向的傾斜角度α的別種處理。第18圖所示的處理,係除了第17圖所示的處理的開始條件之外,又在鑄模長邊2的背面,配置:隔介著鑄模長邊而相對向的一對上部磁極6與一對下部磁極7,將吐出孔配置在:「由上部磁極6所施加的直流靜磁場的最大值的位置」與「由下部磁極7所施加的直流靜磁場的最大值的位置」之間,當該靜磁場的強度為1500Gs以上且未達3500Gs的情況下,就開始進行處理。 Fig. 18 is a flow chart showing an example different from the foregoing. Another treatment for changing the inclination angle α of the discharge direction of the immersion nozzle 4 will be described using FIG. In the processing shown in Fig. 18, in addition to the start condition of the processing shown in Fig. 17, on the back surface of the long side 2 of the mold, a pair of upper magnetic poles 6 opposed to each other across the long side of the mold are disposed. The pair of lower magnetic poles 7 are disposed between the "position of the maximum value of the DC static magnetic field applied by the upper magnetic pole 6" and "the position of the maximum value of the DC static magnetic field applied by the lower magnetic pole 7". When the intensity of the static magnetic field is 1500 Gs or more and less than 3500 Gs, the treatment is started.
在第18圖所示的處理中,角度調整裝置係先 判斷連續鑄造裝置是否為定常的澆鑄中(步驟S201)。角度調整裝置判斷出連續鑄造裝置並不是定常的澆鑄中的情況下(步驟S201:No),就結束第18圖所示的處理。角度調整裝置係當連續鑄造裝置成為定常的澆鑄中的情況下(步驟S201:Yes),角度調整裝置係判斷直流靜磁場的強度是否落在1500≦Gs<2500的範圍內(步驟S202)。角度調整裝置判斷出直流靜磁場的強度落在1500≦Gs<2500的範圍內的情況下(步驟S202:Yes),就進行測定傾斜角度α與θ,並且判斷傾斜角度α是否符合數式(3)的關係(步驟S203)。 In the process shown in Figure 18, the angle adjustment device is first It is judged whether or not the continuous casting apparatus is in a constant casting (step S201). When the angle adjusting device determines that the continuous casting device is not in the constant casting (step S201: No), the processing shown in Fig. 18 is ended. The angle adjusting device is a case where the continuous casting device is in a constant casting (step S201: Yes), and the angle adjusting device determines whether the intensity of the direct current static magnetic field falls within the range of 1500 ≦ Gs < 2500 (step S202). When the angle adjusting device determines that the intensity of the DC static magnetic field falls within the range of 1500 ≦Gs<2500 (step S202: Yes), the inclination angles α and θ are measured, and it is judged whether or not the inclination angle α conforms to the formula (3). Relationship (step S203).
角度調整裝置判斷出傾斜角度α係符合數式(3)的情況下(步驟S203:Yes),就結束第18圖所示的處理。另一方面,角度調整裝置判斷出傾斜角度α並不符合數式(3)的情況下(步驟S203:No),就再設定符合數式(3)的傾斜角度α(步驟S204)。角度調整裝置就以可符合再設定的傾斜角度α的方式,來變更浸漬式噴嘴4的吐出方向(步驟S205),然後,結束第18圖所示的處理。 When the angle adjustment device determines that the inclination angle α is in accordance with the equation (3) (step S203: Yes), the processing shown in Fig. 18 is ended. On the other hand, when the angle adjustment device determines that the inclination angle α does not satisfy the formula (3) (step S203: No), the inclination angle α conforming to the equation (3) is set again (step S204). The angle adjusting device changes the discharge direction of the immersion nozzle 4 so as to conform to the reset inclination angle α (step S205), and then ends the processing shown in Fig. 18.
另一方面,當角度調整裝置判斷出直流靜磁場的強度並未落在1500≦Gs<2500的範圍內,而是落在2500≦Gs<3500的範圍內的情況下(步驟S202:No),就進行測定傾斜角度α與θ,並且判斷傾斜角度α是否符合數式(4)的關係(步驟S206)。當角度調整裝置判斷出傾斜角度α符合數式(4)的情況下(步驟S206:Yes),就結束第18圖所示的處理。另一方面,當角度調整裝置判斷出傾 斜角度α並不符合數式(4)的情況下(步驟S206:No),就再設定符合數式(4)的傾斜角度α(步驟S207)。角度調整裝置就以可符合再設定的傾斜角度α的方式,來變更浸漬式噴嘴4的吐出方向(步驟S208),然後,結束第18圖所示的處理。 On the other hand, when the angle adjusting means determines that the intensity of the DC static magnetic field does not fall within the range of 1500 ≦ Gs < 2500, but falls within the range of 2500 ≦ Gs < 3500 (step S202: No), The inclination angles α and θ are measured, and it is judged whether or not the inclination angle α conforms to the relationship of the formula (4) (step S206). When the angle adjusting means determines that the inclination angle α conforms to the formula (4) (step S206: Yes), the processing shown in Fig. 18 is ended. On the other hand, when the angle adjusting device determines that the tilt When the inclination angle α does not satisfy the formula (4) (step S206: No), the inclination angle α in accordance with the equation (4) is set again (step S207). The angle adjusting device changes the discharge direction of the immersion nozzle 4 so as to conform to the reset inclination angle α (step S208), and then ends the processing shown in Fig. 18.
第19圖係顯示與前述不同之別種例子的流程圖。將使用第19圖來說明變更浸漬式噴嘴4的吐出方向的傾斜角度α之別種處理。第19圖所示的處理,係除了第17圖所示的處理的開始條件之外,又設置了:將磁場的移動方向設在鑄模寬度方向上的直線型移動磁場發生裝置42的情況下開始進行處理。 Fig. 19 is a flow chart showing another example different from the foregoing. The other processing of changing the inclination angle α of the discharge direction of the immersion nozzle 4 will be described using FIG. The processing shown in Fig. 19 is performed in addition to the start condition of the processing shown in Fig. 17, in the case where the moving direction of the magnetic field is set to the linear moving magnetic field generating device 42 in the width direction of the mold. Process it.
在第19圖所示的處理中,角度調整裝置係先判斷連續鑄造裝置是否處在定常的澆鑄中(步驟S301)。角度調整裝置判斷出連續鑄造裝置並不是處在定常的澆鑄中的情況下(步驟S301:No),就結束第19圖所示的處理。角度調整裝置,當連續鑄造裝置已變成定常的澆鑄中的情況下(步驟S301:Yes),角度調整裝置就測定傾斜角度α與θ,並且判斷傾斜角度α是否符合數式(5)的關係(步驟S302)。當角度調整裝置判斷出傾斜角度α已符合數式(5)的情況下(步驟S302:Yes),就結束第19圖所示的處理。另一方面,角度調整裝置若判斷出傾斜角度α並不符合數式(5)的情況下(步驟S302:No),就再設定符合數式(5)的傾斜角度α(步驟S303)。角度調整裝置,係以可形成再設定的傾斜角度α的方式,來變更浸漬式噴嘴4的吐出方向 (步驟S304),然後,結束第19圖所示的處理。 In the processing shown in Fig. 19, the angle adjusting means first judges whether or not the continuous casting apparatus is in a constant casting (step S301). When the angle adjusting device determines that the continuous casting device is not in the constant casting (step S301: No), the processing shown in Fig. 19 is ended. The angle adjusting device, when the continuous casting device has become a constant casting (step S301: Yes), the angle adjusting device measures the inclination angles α and θ, and determines whether the inclination angle α conforms to the relationship of the formula (5) ( Step S302). When the angle adjusting means determines that the inclination angle ? has satisfied the formula (5) (step S302: Yes), the processing shown in Fig. 19 is ended. On the other hand, when it is judged that the inclination angle α does not satisfy the formula (5) (step S302: No), the angle adjustment device sets the inclination angle α in accordance with the equation (5) (step S303). The angle adjusting device changes the discharge direction of the immersion nozzle 4 so that the reset inclination angle α can be formed. (Step S304), then the processing shown in Fig. 19 is ended.
第20圖係顯示與前述不同之別種例子的流程圖。將使用第20圖來說明變更浸漬式噴嘴4的吐出方向的傾斜角度α之別種處理。第20圖所示的處理,係除了第17圖所示的處理的開始條件之外,又在鑄模長邊2的背面具備一對磁極52,由該磁極施加300~1000Gs的範圍內的強度之交流移動磁場,當交流移動磁場的強度與鋼胚鑄片的寬度之比值X/W為0.30以上且未達0.55的情況下開始進行處理。 Fig. 20 is a flow chart showing another example different from the foregoing. The other treatment for changing the inclination angle α of the discharge direction of the immersion nozzle 4 will be described using FIG. In the process shown in Fig. 20, in addition to the start condition of the process shown in Fig. 17, a pair of magnetic poles 52 are provided on the back surface of the long side 2 of the mold, and the strength in the range of 300 to 1000 Gs is applied from the magnetic pole. The alternating moving magnetic field is started when the ratio X/W of the intensity of the alternating moving magnetic field to the width of the steel slab is 0.30 or more and less than 0.55.
在第20圖所示的處理中,角度調整裝置係先判斷連續鑄造裝置是否處在定常的澆鑄中(步驟S401)。角度調整裝置判斷出連續鑄造裝置並不是處在定常的澆鑄中的情況下(步驟S401:No),就結束第20圖所示的處理。角度調整裝置,當連續鑄造裝置已變成定常的澆鑄中的情況下(步驟S401:Yes),角度調整裝置就判斷X/W的比值是否為0.30以上且未達0.45(步驟S402)。當角度調整裝置判斷出X/W的比值為0.30以上且未達0.45的情況下(步驟S402:Yes),就進行測定傾斜角度α與θ,並且判斷傾斜角度α是否符合數式(6)的關係(步驟S403)。 In the processing shown in Fig. 20, the angle adjusting means first judges whether or not the continuous casting apparatus is in a constant casting (step S401). When the angle adjusting device determines that the continuous casting device is not in the constant casting (step S401: No), the processing shown in Fig. 20 is ended. In the case where the continuous casting apparatus has become a constant casting (step S401: Yes), the angle adjusting means determines whether the ratio of X/W is 0.30 or more and less than 0.45 (step S402). When the angle adjusting device determines that the ratio of X/W is 0.30 or more and does not reach 0.45 (step S402: Yes), the inclination angles α and θ are measured, and it is judged whether or not the inclination angle α conforms to the formula (6). Relationship (step S403).
當角度調整裝置判斷出傾斜角度α符合數式(6)的情況下(步驟S403:Yes),就結束第20圖所示的處理。另一方面,角度調整裝置若判斷出傾斜角度α並不符合數式(6)的情況下(步驟S403:No),就再設定符合數式(6)的傾斜角度α(步驟S404)。角度調整裝置,係以可形 成再設定的傾斜角度α的方式,來變更浸漬式噴嘴4的吐出方向(步驟S405),然後,結束第20圖所示的處理。 When the angle adjusting means determines that the inclination angle ? corresponds to the equation (6) (step S403: Yes), the processing shown in Fig. 20 is ended. On the other hand, when the angle adjustment device determines that the inclination angle α does not satisfy the formula (6) (step S403: No), the inclination angle α in accordance with the equation (6) is set again (step S404). Angle adjustment device The discharge direction of the immersion nozzle 4 is changed so that the inclination angle α is set again (step S405), and the process shown in FIG. 20 is completed.
另一方面,角度調整裝置判斷出X/W的比值並不是0.30以上且未達0.45。而是0.45以上且未達0.55的情況下(步驟S402:No),就進行測定傾斜角度α與θ,並且判斷傾斜角度α是否符合數式(7)的關係(步驟S406)。 On the other hand, the angle adjusting device determines that the ratio of X/W is not 0.30 or more and less than 0.45. When it is 0.45 or more and less than 0.55 (step S402: No), the inclination angles α and θ are measured, and it is judged whether or not the inclination angle α satisfies the relationship of the formula (7) (step S406).
角度調整裝置判斷出傾斜角度α符合數式(7)的情況下(步驟S406:Yes),就結束第20圖所示的處理。另一方面,角度調整裝置判斷出傾斜角度α並不符合數式(7)的情況下(步驟S406:No),就再設定符合數式(7)的傾斜角度α(步驟S407)。角度調整裝置係以可形成再設定的傾斜角度α的方式,來變更浸漬式噴嘴4的吐出方向(步驟S408),然後結束第20圖所示的處理。 When the angle adjustment device determines that the inclination angle α conforms to the equation (7) (step S406: Yes), the processing shown in Fig. 20 is ended. On the other hand, when the angle adjustment device determines that the inclination angle α does not satisfy the formula (7) (step S406: No), the inclination angle α conforming to the equation (7) is set again (step S407). The angle adjusting device changes the discharge direction of the immersion nozzle 4 so that the reset inclination angle α can be formed (step S408), and then ends the processing shown in Fig. 20.
第21圖係顯示與前述不同的別種例子的流程圖。使用第21圖來說明變更浸漬式噴嘴4的吐出方向的傾斜角度α之別種處理。第21圖所示的處理,係除了第17圖所示的處理的開始條件之外,又在鑄模長邊的背面,配置了隔介著鑄模長邊而相對向的一對上部磁極6與一對下部磁極7,並且將吐出孔配置由上部磁極6所施加的直流靜磁場的最大值的位置與由下部磁極7所施加的直流靜磁場的最大值的位置之間,重疊地施加:由上部磁極6所施加的500~900Gs的範圍內的強度的交流移動磁場,以及2000~3300Gs的範圍內的強度的直流靜磁場, 由下部磁極7所施加的3000~4500Gs的範圍內的強度的直流靜磁場,在交流移動磁場的強度與鋼胚鑄片的寬度之X/W的比值為0.30以上且未達0.55的情況下開始進行處理。 Fig. 21 is a flow chart showing another example different from the foregoing. The other processing of changing the inclination angle α of the discharge direction of the immersion nozzle 4 will be described using Fig. 21 . In the process shown in Fig. 21, in addition to the start condition of the process shown in Fig. 17, a pair of upper magnetic poles 6 and one facing each other across the long side of the mold are disposed on the back side of the long side of the mold. The lower magnetic pole 7 is disposed so as to overlap the position where the discharge hole is disposed at the maximum value of the DC static magnetic field applied by the upper magnetic pole 6 and the maximum value of the DC static magnetic field applied by the lower magnetic pole 7: The AC moving magnetic field of the intensity in the range of 500 to 900 Gs applied by the magnetic pole 6, and the DC static magnetic field of the intensity in the range of 2000 to 3300 Gs, The DC static magnetic field of the intensity in the range of 3000 to 4500 Gs applied by the lower magnetic pole 7 starts when the ratio of the intensity of the AC moving magnetic field to the X/W of the width of the steel slab is 0.30 or more and less than 0.55. Process it.
在第21圖所示的處理中,角度調整裝置係判斷連續鑄造裝置是否處在定常的澆鑄中(步驟S501)。角度調整裝置判斷出連續鑄造裝置並不是定常的澆鑄中的情況下(步驟S501:No),就結束第21圖所示的處理。角度調整裝置係在連續鑄造裝置處在定常的澆鑄中的情況下(步驟S501:Yes),角度調整裝置才進行判斷X/W的比值是否為0.30以上且未達0.45(步驟S502)。角度調整裝置判斷出X/W的比值為0.30以上且未達0.45的情況下(步驟S502:Yes),就測定傾斜角度α與θ,並且判斷傾斜角度α是否符合數式(8)的關係(步驟S503)。 In the process shown in Fig. 21, the angle adjusting means determines whether or not the continuous casting device is in a constant casting (step S501). When the angle adjusting device determines that the continuous casting device is not in the constant casting (step S501: No), the processing shown in Fig. 21 is ended. When the angle adjusting device is in the constant casting (step S501: Yes), the angle adjusting device determines whether the ratio of X/W is 0.30 or more and less than 0.45 (step S502). When the angle adjusting device determines that the ratio of X/W is 0.30 or more and does not reach 0.45 (step S502: Yes), the inclination angles α and θ are measured, and it is judged whether or not the inclination angle α conforms to the relationship of the formula (8) ( Step S503).
角度調整裝置判斷出傾斜角度α符合數式(8)的情況下(步驟S503:Yes),就結束第21圖所示的處理。另一方面,角度調整裝置判斷出傾斜角度α並不符合數式(8)的情況下(步驟S503:No),就再設定符合數式(8)的傾斜角度α(步驟S504)。角度調整裝置係以可形成再設定的傾斜角度α的方式來變更浸漬式噴嘴4的吐出方向(步驟S505),然後結束第21圖所示的處理。 When the angle adjusting device determines that the tilt angle α corresponds to the equation (8) (step S503: Yes), the processing shown in Fig. 21 is ended. On the other hand, when the angle adjusting device determines that the inclination angle α does not satisfy the formula (8) (step S503: No), the inclination angle α in accordance with the equation (8) is set again (step S504). The angle adjusting device changes the discharge direction of the immersion nozzle 4 so that the reset inclination angle α can be formed (step S505), and then ends the processing shown in Fig. 21.
另一方面,角度調整裝置判斷出X/W的比值並不是0.30以上且未達0.45,而是0.45以上且未達0.55的情況下(步驟S502:No),就測定傾斜角度α與θ,並 且判斷傾斜角度α是否符合數式(9)的關係(步驟S506)。 On the other hand, when the angle adjusting device determines that the ratio of X/W is not 0.30 or more and does not reach 0.45, but is 0.45 or more and less than 0.55 (step S502: No), the inclination angles α and θ are measured, and And it is judged whether or not the inclination angle α satisfies the relationship of the formula (9) (step S506).
角度調整裝置判斷出傾斜角度α符合數式(9)的情況下(步驟S506:Yes),就結束第21圖所示的處理。另一方面,角度調整裝置判斷出傾斜角度α並不符合數式(9)的情況下(步驟S506:No),就再設定符合數式(9)的傾斜角度α(步驟S507)。角度調整裝置係以可形成再設定的傾斜角度α的方式來變更浸漬式噴嘴4的吐出方向(步驟S508),然後結束第21圖所示的處理。 When the angle adjusting device determines that the inclination angle α conforms to the formula (9) (step S506: Yes), the processing shown in Fig. 21 is ended. On the other hand, when the angle adjustment device determines that the inclination angle α does not satisfy the formula (9) (step S506: No), the inclination angle α in accordance with the equation (9) is set again (step S507). The angle adjusting device changes the discharge direction of the immersion nozzle 4 so that the reset inclination angle α can be formed (step S508), and then the processing shown in Fig. 21 is ended.
第22圖係依據鑄造條件來分開使用第17圖~第21圖的各種處理之一例的流程圖。在第22圖所示的例子中,角度調整裝置係每隔預先設定的時間,就進行確認鑄造條件,並且依據該鑄造條件的不同,來分開使用第17圖~第21圖所記載的處理。當角度調整裝置判斷出符合:「浸漬式噴嘴4的浸漬深度為180mm以上且未達300mm,吐出孔之從水平方向朝下方的熔鋼吐出角度為15~35°,吹入到從澆鑄槽流出孔起迄吐出孔之間的鈍氣的流量A(NL/min)與熔鋼吞吐量P(ton/min)的比值A/P落在2.0~3.5NL/ton的範圍內」之所謂的「條件A」的情況下,就執行第17圖所示的變更吐出方向的傾斜角度α的處理。 Fig. 22 is a flow chart showing an example of various processes of Figs. 17 to 21 in accordance with casting conditions. In the example shown in Fig. 22, the angle adjusting device performs the checking of the casting conditions every predetermined time, and separately uses the processes described in Figs. 17 to 21 depending on the casting conditions. When the angle adjusting device determines that the immersion depth of the immersion nozzle 4 is 180 mm or more and less than 300 mm, the molten steel discharge angle of the discharge hole from the horizontal direction to the lower side is 15 to 35°, and is blown into the flow from the casting groove. The ratio A/P of the flow rate A (P/ton) of the blunt gas between the hole and the discharge hole to the molten steel throughput P (ton/min) falls within the range of 2.0 to 3.5 NL/ton. In the case of the condition A", the process of changing the inclination angle α in the discharge direction shown in Fig. 17 is executed.
又,角度調整裝置判斷出符合:「除了條件A之外,在鑄模長邊的背面配置有隔介著鑄模長邊而相對向的一對上部磁極6與一對下部磁極7,並且將吐出孔配置在由上部磁極6所施加的直流靜磁場的最大值的位置與 由下部磁極7所施加的直流靜磁場的最大值的位置之間,且該靜磁場的強度為1500Gs以上且未達3500Gs」之所謂的「條件B」的情況下,就執行第18圖所示的變更吐出方向的傾斜角度α的處理。 Further, the angle adjusting device determines that the pair of upper magnetic poles 6 and the pair of lower magnetic poles 7 that face each other with the long side of the mold are disposed on the back side of the long side of the mold in addition to the condition A, and the discharge hole is formed. Positioned at the maximum value of the DC static magnetic field applied by the upper magnetic pole 6 When the position of the maximum value of the DC static magnetic field applied by the lower magnetic pole 7 is between 1500 Gs or more and the intensity of the static magnetic field is less than 3500 Gs, the condition B is as shown in FIG. The process of changing the inclination angle α of the discharge direction.
又,角度調整裝置判斷出符合:「除了條件A之外,又設有磁場的移動方向係沿著鑄模寬度方向的直線型移動磁場發生裝置42」之所謂的「條件C」的情況下,就執行第19圖所示的變更吐出方向的傾斜角度α的處理。 In addition, when the angle adjustment device determines that the condition C is in addition to the condition A, the so-called "condition C" in which the moving direction of the magnetic field is along the linear direction of the mold width is "condition C" The process of changing the inclination angle α of the discharge direction shown in Fig. 19 is performed.
又,角度調整裝置判斷出符合:「除了條件A之外,又在長邊背面具備一對磁極52,由磁極52施加300~1000Gs的範圍內的強度的交流移動磁場,並且交流移動磁場的強度與鋼胚鑄片的寬度之比值X/W為0.30以上且未達0.55」之所謂的「條件D」的情況下,就執行第20圖所示的變更吐出方向的傾斜角度α的處理。 Further, the angle adjusting device determines that "the magnetic pole 52 is provided on the back side of the long side in addition to the condition A, and the alternating magnetic field of the intensity in the range of 300 to 1000 Gs is applied from the magnetic pole 52, and the intensity of the alternating magnetic field is applied. In the case of the so-called "condition D" in which the ratio X/W of the width of the steel slab is 0.30 or more and less than 0.55", the process of changing the inclination angle α in the discharge direction shown in Fig. 20 is executed.
此外,角度調整裝置判斷出符合:「除了條件A之外,又在鑄模長邊的背面配置了隔介著鑄模長邊而相對向的一對上部磁極6與一對下部磁極7,將吐出孔配置在由上部磁極6所施加的直流靜磁場的最大值的位置與由下部磁極7所施加的直流靜磁場的最大值的位置之間,由上部磁極6重疊地施加500~900Gs的範圍內的強度的交流移動磁場以及2000~3300Gs的範圍內的強度的直流靜磁場,由下部磁極7施加3000~4500Gs的範圍內的強度的直流靜磁場,並且交流移動磁場的強度與鋼胚鑄片的 寬度的比值X/W係0.30以上且未達0.55」之所謂的「條件E」的情況下,就執行第21圖所示的變更吐出方向的傾斜角度α的處理。 Further, the angle adjusting device determines that "in addition to the condition A, a pair of upper magnetic poles 6 and a pair of lower magnetic poles 7 that face each other across the long side of the mold are disposed on the back side of the long side of the mold, and the discharge holes are formed. Between the position where the maximum value of the DC static magnetic field applied by the upper magnetic pole 6 and the maximum value of the DC static magnetic field applied by the lower magnetic pole 7 are placed, the upper magnetic pole 6 is overlapped and applied in the range of 500 to 900 Gs. The intensity of the AC moving magnetic field and the DC static magnetic field of the intensity in the range of 2000 to 3300 Gs, the DC static magnetic field of the intensity in the range of 3000 to 4500 Gs is applied by the lower magnetic pole 7, and the strength of the AC moving magnetic field and the strength of the steel embryo casting When the ratio X/W of the width is 0.30 or more and the condition E is less than 0.55", the processing of changing the inclination angle α in the discharge direction shown in Fig. 21 is executed.
是以,本實施方式中的角度調整裝置,係每隔預先設定的時間,就執行變更與鑄造條件相對應的傾斜角度α的處理,如果判斷出傾斜角度α並不符合與鑄造條件相對應的數式(1)、(3)~(9)的話,就變更浸漬式噴嘴4的吐出方向來謀求符合該數式。如此一來,即使是在因為某種原因而導致傾斜角度α不符合數式(3)~(9)的情況下,亦可利用角度調整裝置來變更浸漬式噴嘴4的吐出方向來謀求可符合該數式的關係,因此,可防止連續地製造出含有夾雜物的鋼胚鑄片。 Therefore, the angle adjusting device according to the present embodiment performs the process of changing the tilt angle α corresponding to the casting condition every predetermined time, and determines that the tilt angle α does not correspond to the casting condition. In the case of the equations (1) and (3) to (9), the discharge direction of the immersion nozzle 4 is changed to conform to the equation. In this way, even if the inclination angle α does not satisfy the equations (3) to (9) for some reason, the angle adjustment device can be used to change the discharge direction of the immersion nozzle 4 to achieve compliance. According to the relationship of the equations, it is possible to prevent the steel slabs containing inclusions from being continuously produced.
如上所述,藉由採用本實施方式的連續鑄造方法,除了可將由上部磁極及下部磁極所施加的直流靜磁場的強度和交流移動磁場的強度等予以設定在最佳範圍內,並且可使來自浸漬式噴嘴的吐出方向朝向由交流移動磁場所產生的迴旋流的上游側傾斜,因此,可以避免由於迴旋流與反轉流的互相衝撞和干擾而產生的低流速領域及渦流,能夠製造出夾雜物很少之高品質的鋼胚鑄片。 As described above, by using the continuous casting method of the present embodiment, in addition to the intensity of the DC static magnetic field and the intensity of the AC moving magnetic field applied by the upper magnetic pole and the lower magnetic pole, the optimum range can be set and can be derived from The discharge direction of the immersion nozzle is inclined toward the upstream side of the swirling flow generated by the alternating current moving magnetic field, so that low flow velocity fields and eddy currents due to mutual collision and interference between the swirling flow and the reverse flow can be avoided, and inclusions can be produced. High quality steel slabs with few materials.
[實施例1] [Example 1]
使用具有第1圖所示的連續鑄造用鑄模20的鋼胚連續鑄造機,進行鑄造約300(ton)的鋁(脫氧)鎮靜熔鋼的鑄造試驗。所鑄造的鋼胚鑄片的厚度是250(mm),寬 度是1000~2000(mm),熔鋼注入流量是3.0~8.0(ton/min)。所使用的兩孔式浸漬式噴嘴的吐出孔的熔鋼吐出角度(將水平狀態視為角度是零)是朝下方15(°),浸漬式噴嘴的浸漬深度(從鑄模內熔鋼湯面起迄吐出孔上端為止的距離)是180(mm)以上且未達300(mm)。浸漬式噴嘴的吐出孔的形狀,是每一邊的長度為80(mm)的正方形,浸漬式噴嘴的內徑是80(mm)。又,來自浸漬式噴嘴的吹入鈍氣係使用氬氣。來自浸漬式噴嘴的吐出流的吐出方向,係有兩種方向,一種是與鑄模長邊平行的方向(與鑄模短邊垂直的方向);另外一種是對於基準面呈傾斜的方向。 A casting test of aluminum (deoxidized) killed molten steel of about 300 (ton) was carried out using a steel continuous casting machine having the continuous casting mold 20 shown in Fig. 1. The thickness of the cast steel slab is 250 (mm), wide The degree is 1000~2000 (mm), and the molten steel injection flow rate is 3.0~8.0 (ton/min). The molten steel discharge angle of the discharge hole of the two-hole type immersion nozzle used (the horizontal state is regarded as the angle is zero) is 15 (°) downward, and the immersion depth of the immersion nozzle (from the molten steel noodle soup in the mold) The distance from the upper end of the discharge hole is 180 (mm) or more and less than 300 (mm). The shape of the discharge hole of the immersion nozzle is a square having a length of 80 (mm) on each side, and the inner diameter of the immersion nozzle is 80 (mm). Further, argon gas was used for the blow-in air from the immersion nozzle. The discharge direction of the discharge flow from the immersion nozzle has two directions, one is a direction parallel to the long side of the mold (direction perpendicular to the short side of the mold), and the other is a direction inclined with respect to the reference surface.
針對於所鑄造出來的鋼胚鑄片,依序實施:熱軋、冷軋、合金化熔融鍍鋅處理,使用線上(on line)表面缺陷計連續地測定這種合金化熔融鍍鋅鋼板的表面缺陷,再從所測定到的結果當中,藉由觀察缺陷的外觀以及進行SEM分析、ICP分析等項目,來判別出:製鋼性的缺陷(由鋼胚鑄片的夾雜物所引起的缺陷),再以合金化熔融鍍鋅鋼板之每100(m)長度中的缺陷個數(也稱為「製品缺陷指數」)來進行評比。表1中係顯示出本發明例1~18及比較例1~18的鑄造條件以及製品缺陷指數的調查結果。 For the cast steel slabs, the steel slabs are sequentially processed: hot rolling, cold rolling, alloying hot galvanizing, and the surface of the alloyed galvanized steel sheet is continuously measured using an on line surface defect meter. Defects, and from the measured results, by observing the appearance of the defects and performing SEM analysis, ICP analysis, and the like, it is determined that the steel defects (defects caused by the inclusions of the steel slabs), The number of defects per 100 (m) length of the alloyed hot-dip galvanized steel sheet (also referred to as "product defect index") was evaluated. Table 1 shows the results of investigations on casting conditions and product defect indexes of Inventive Examples 1 to 18 and Comparative Examples 1 to 18.
表1中係記載著:以所鑄造的鑄片的厚度D與鑄片的寬度W來計算出來的對角線方向角度θ以及鑄造時的吐出流的傾斜角度α。此外,對角線方向角度θ,係將小數點第2位予以四捨五入而計算出來的。又,表1中所記載的「α-θ」的數值,係將小數點第1位予以四捨五入後的數值。 Table 1 shows the diagonal direction angle θ calculated from the thickness D of the cast slab and the width W of the cast piece, and the inclination angle α of the discharge flow at the time of casting. In addition, the diagonal direction angle θ is calculated by rounding off the second decimal place. Further, the numerical value of "α-θ" described in Table 1 is a numerical value obtained by rounding off the first decimal place.
可以看出:在本發明例1~18中,因為除了是將熔鋼 吞吐量與氬氣流量的比值A/P設定成落在2.0~3.5(NL/ton)的範圍內之外,也將「α-θ」設定在-6~10(°)的範圍內,因此,製品缺陷指數很低,只有0.26~0.29(個/100m)而已。亦即,可以得知:藉由將傾斜角度α(°)設定在「θ-6」以上且「θ+10」以下的範圍內,可賦予熔鋼流合適的流速,而可降低製品缺陷指數。 It can be seen that in the inventive examples 1 to 18, because in addition to being molten steel The ratio A/P of the throughput to the argon flow rate is set to fall within the range of 2.0 to 3.5 (NL/ton), and "α-θ" is also set within the range of -6 to 10 (°). The product defect index is very low, only 0.26~0.29 (pieces/100m). That is, it can be known that by setting the inclination angle α (°) within a range of “θ-6” or more and “θ+10” or less, a suitable flow velocity of the molten steel flow can be imparted, and the product defect index can be lowered. .
相對於此,比較例1~6並未將吐出方向保持傾斜,因此,製品缺陷指數偏高而達到0.61~0.68(個/100m)。又,比較例7~9的傾斜角度α係小於本發明例1~18,這種情況的製品缺陷指數也是偏高而達到0.63~0.67(個/100m)。其原因被推定:是因為傾斜角度α太小,因而無法賦予熔鋼流合適的流速之結果。 On the other hand, in Comparative Examples 1 to 6, the discharge direction was not inclined, and thus the product defect index was high and reached 0.61 to 0.68 (pieces/100 m). Further, the inclination angles α of Comparative Examples 7 to 9 were smaller than those of Examples 1 to 18 of the present invention, and the product defect index in this case was also high to 0.63 to 0.67 (pieces/100 m). The reason for this is presumed: it is because the inclination angle α is too small to give a suitable flow rate of the molten steel flow.
比較例10~12的傾斜角度α係大於本發明例1~18。這種情況的製品缺陷指數雖然降低成0.27~0.29(個/100m)的程度,但是,從鑄片剖面的調查結果,發現了在鑄模內的鑄片外殼的成長厚度係有較薄的地方,而有發生鑄漏現象之類的阻礙作業穩定性的可能性。 The inclination angles α of Comparative Examples 10 to 12 were larger than those of Examples 1 to 18 of the present invention. In this case, the product defect index is reduced to 0.27 to 0.29 (pieces/100 m). However, from the investigation results of the cast sheet profile, it has been found that the growth thickness of the cast shell in the mold is thin. There is a possibility that the occurrence of casting leakage phenomenon hinders the stability of the work.
比較例13~18之熔鋼吞吐量P與氬氣流量A的比值A/P係落在2.0~3.5(NL/ton)的範圍外,這種情況的製品缺陷指數偏高而達到0.61~0.68(個/100m)。其原因被推定:是因為無法控制吐出噴流,從而無法發揮將吐出方向設成傾斜的效果之結果。 The ratio A/P of the molten steel throughput P to the argon flow rate A of Comparative Examples 13 to 18 falls outside the range of 2.0 to 3.5 (NL/ton). In this case, the product defect index is high and reaches 0.61 to 0.68. (one / 100m). The reason for this is presumed: it is because the discharge jet cannot be controlled, and the effect of setting the discharge direction to be inclined cannot be exhibited.
此外,在本實施例中雖然並未記載出來,但是也另外又確認出來:即使所鑄造的鋼胚鑄片的厚度係在 220~300(mm)的範圍內,還是可以獲得與本實施例所記載的鋼胚鑄片同等程度的效果。此外,也確認出來:浸漬式噴嘴的熔鋼吐出角度落在15~35(°)的範圍內亦可獲得同樣的傾向。其他,關於浸漬式噴嘴的吐出孔的形狀和浸漬式噴嘴的內徑,並不是只限定本實施例所記載的條件,只要是本行業者所能想到的範圍內的話,也都無妨。 Further, although not described in the present embodiment, it is additionally confirmed that even if the thickness of the cast steel slab is In the range of 220 to 300 (mm), the same effect as that of the steel blank cast piece described in the present embodiment can be obtained. In addition, it was confirmed that the same tendency was obtained in the range in which the molten steel discharge angle of the immersion nozzle fell within the range of 15 to 35 (°). In addition, the shape of the discharge hole of the immersion nozzle and the inner diameter of the immersion nozzle are not limited to the conditions described in the present embodiment, and may be any extent as long as it is within the range that can be considered by those skilled in the art.
[實施例2] [Embodiment 2]
使用具有第4圖所示的上部磁極6、下部磁極7的連續鑄造用鑄模30之鋼胚連續鑄造機,進行鑄造約300(ton)的鋁(脫氧)鎮靜熔鋼的鑄造試驗。所鑄造的鋼胚鑄片的厚度是250(mm),寬度是1800(mm),熔鋼注入流量是5.0~8.0(ton/min)。所使用的兩孔式浸漬式噴嘴的吐出孔的吐出角度是朝下方15(°),浸漬式噴嘴的浸漬深度(從鑄模內熔鋼湯面起迄吐出孔上端為止的距離)是180(mm)以上且未達300(mm)。浸漬式噴嘴的吐出孔的形狀,是每一邊的長度為80(mm)的正方形,浸漬式噴嘴的內徑是80(mm)。又,從浸漬式噴嘴吹入的鈍氣係使用氬氣。熔鋼吞吐量P與氬氣流量A的比值A/P是設定成落在2.0~3.5(NL/ton)的範圍內。 A casting test of aluminum (deoxidized) killed molten steel of about 300 (ton) was carried out using a steel continuous casting machine having a continuous casting mold 30 having an upper magnetic pole 6 and a lower magnetic pole 7 shown in Fig. 4 . The cast steel slab has a thickness of 250 (mm), a width of 1800 (mm), and a molten steel injection flow rate of 5.0 to 8.0 (ton/min). The discharge angle of the discharge hole of the two-hole type immersion nozzle used is 15 (°) downward, and the immersion depth of the immersion nozzle (the distance from the molten steel soup surface in the mold to the upper end of the discharge hole) is 180 (mm). Above and less than 300 (mm). The shape of the discharge hole of the immersion nozzle is a square having a length of 80 (mm) on each side, and the inner diameter of the immersion nozzle is 80 (mm). Further, argon gas was used as the blunt gas blown from the immersion nozzle. The ratio A/P of the molten steel throughput P to the argon flow rate A is set to fall within the range of 2.0 to 3.5 (NL/ton).
來自浸漬式噴嘴的吐出流的吐出方向,係有兩種方向,一種是與鑄模長邊平行的方向(與鑄模短邊垂直的方向);另外一種是對於基準面呈傾斜的方向。 The discharge direction of the discharge flow from the immersion nozzle has two directions, one is a direction parallel to the long side of the mold (direction perpendicular to the short side of the mold), and the other is a direction inclined with respect to the reference surface.
針對於所鑄造出來的鋼胚鑄片,依序實施: 熱軋、冷軋、合金化熔融鍍鋅處理,使用線上(on line)表面缺陷計連續地測定這種合金化熔融鍍鋅鋼板的表面缺陷,再從所測定到的結果當中,藉由觀察缺陷的外觀以及進行SEM分析、ICP分析等項目,來判別出:製鋼性的缺陷(由鋼胚鑄片的夾雜物所引起的缺陷),再以合金化熔融鍍鋅鋼板之每100(m)長度中的缺陷個數(也稱為「製品缺陷指數」)來進行評比。表2係顯示:本發明例19~38以及比較例19~32的鑄造條件以及製品缺陷指數的調查結果。在表2中也是同樣地,對角線方向角度θ,係將小數點第2位予以四捨五入而計算出來的。又,表2中所記載的對角線方向角度θ的數值,係將小數點第2位予以四捨五入後的數值。又,「α-θ」的數值,係將小數點第1位予以四捨五入後的數值。第23圖係將本發明例19~38的「α-θ」與「製品缺陷指數」的關係,以2500(Gs)的靜磁場強度作為境界予以分區顯示的圖。 For the cast steel slab cast, it is implemented in order: Hot rolling, cold rolling, alloying hot-dip galvanizing treatment, using the on line surface defect meter to continuously measure the surface defects of the alloyed hot-dip galvanized steel sheet, and then observing the defects from the measured results The appearance and the SEM analysis, ICP analysis, etc., to determine the defects of the steelmaking (defects caused by the inclusions of the steel slab), and then the length of each 100 (m) of the alloyed hot-dip galvanized steel sheet The number of defects in the middle (also known as the "product defect index") is used for evaluation. Table 2 shows the results of investigations on casting conditions and product defect indexes of Inventive Examples 19 to 38 and Comparative Examples 19 to 32. Similarly in Table 2, the diagonal direction angle θ is calculated by rounding off the second decimal place. Further, the numerical value of the diagonal direction angle θ described in Table 2 is a value obtained by rounding off the second decimal place. Further, the value of "α-θ" is a value obtained by rounding off the first decimal place. Fig. 23 is a view showing the relationship between "α-θ" and "product defect index" of Examples 19 to 38 of the present invention, and the static magnetic field strength of 2500 (Gs) is used as a boundary.
本發明例19~28係將直流靜磁場強度設定為1500(Gs)以上且未達2500(Gs)。從第23圖可以得知:在這種情況下,藉由將「α-θ」設定在0~5(°)的範圍內,可使得製品缺陷指數更低而達到0.21~0.24(個/100m)。也就是說,可以得知:在將直流靜磁場強度設定為1500(Gs)以上且未達2500(Gs)的情況下,係將傾斜角度α(°)設定成落在「θ」以上且「θ+5」以下的範圍內為宜。 In Examples 19 to 28 of the present invention, the DC static magnetic field strength was set to 1500 (Gs) or more and less than 2500 (Gs). It can be seen from Fig. 23 that in this case, by setting "α-θ" in the range of 0 to 5 (°), the defect index of the product can be made lower and reach 0.21 to 0.24 (pieces/100 m). ). In other words, when the DC static magnetic field strength is set to 1500 (Gs) or more and less than 2500 (Gs), the inclination angle α (°) is set to fall below "θ" and " It is preferable to be in the range of θ + 5" or less.
又,本發明例29~38係將直流靜磁場強度設定成2500(Gs)以上且未達3500(Gs)。可以得知:在這種情況下,藉由將「α-θ」設定成落在6~10(°)的範圍內,可使得製品缺陷指數變得更低而達到0.21~0.24(個/100m)。 也就是說,可以得知:在將直流靜磁場強度設定為2500(Gs)以上且未達3500(Gs)的情況下,係將傾斜角度α(°)設定成落在「θ+6」以上且「θ+10」以下的範圍內為宜。 Further, in Examples 29 to 38 of the present invention, the DC static magnetic field strength was set to 2500 (Gs) or more and less than 3500 (Gs). It can be known that in this case, by setting "α-θ" to fall within the range of 6 to 10 (°), the defect index of the product can be made lower to 0.21 to 0.24 (pieces/100 m). ). In other words, it can be seen that when the DC static magnetic field strength is set to 2500 (Gs) or more and less than 3500 (Gs), the inclination angle α (°) is set to fall below "θ + 6". It is preferable to use a range of "θ+10" or less.
比較例19~23以及比較例26~30,係將傾斜角度α設定成小於「θ-6」。這種情況的製品缺陷指數昇高為0.51~0.54(個/100m)。又,比較例24~25以及比較例31~32,係將傾斜角度α設定成大於「θ+10」。這種情況的製品缺陷指數,雖然降低成0.22~0.25(個/100m),但是,從鑄片剖面的調查結果,發現了在鑄模內的鑄片外殼的成長厚度係有較薄的地方,而有發生鑄漏現象之類的阻礙作業穩定性的可能性。 In Comparative Examples 19 to 23 and Comparative Examples 26 to 30, the inclination angle α was set to be smaller than "θ-6". In this case, the product defect index is increased by 0.51 to 0.54 (pieces/100 m). Further, in Comparative Examples 24 to 25 and Comparative Examples 31 to 32, the inclination angle α was set to be larger than "θ + 10". In this case, the product defect index is reduced to 0.22 to 0.25 (pieces per 100 m). However, from the investigation results of the cast sheet profile, it has been found that the growth thickness of the cast shell in the mold is thinner, and There is a possibility of hindering the stability of the work such as the occurrence of casting leakage.
此外,在本實施例中雖然並未記載出來,但是也另外又確認出來:即使所鑄造的鋼胚鑄片的厚度在220~300(mm)、鑄造寬度為1000~2000(mm)、熔鋼吞吐量為3.0~8.0的範圍內,還是可以獲得與本實施例所記載的鋼胚鑄片同等程度的效果。此外,也確認出來:浸漬式噴嘴的熔鋼吐出角度落在15~35(°)的範圍內亦可獲得同樣的傾向。其他,關於浸漬式噴嘴的吐出孔的形狀和浸漬式噴嘴的內徑,並不是只限定本實施例所記載的條件,只要是本行業者所能想到的範圍內的話,也都無妨。 In addition, although not described in the present embodiment, it is additionally confirmed that even if the cast steel slab has a thickness of 220 to 300 (mm) and a casting width of 1000 to 2000 (mm), molten steel In the range of the throughput of 3.0 to 8.0, the same effect as that of the steel slab cast described in the present embodiment can be obtained. In addition, it was confirmed that the same tendency was obtained in the range in which the molten steel discharge angle of the immersion nozzle fell within the range of 15 to 35 (°). In addition, the shape of the discharge hole of the immersion nozzle and the inner diameter of the immersion nozzle are not limited to the conditions described in the present embodiment, and may be any extent as long as it is within the range that can be considered by those skilled in the art.
[實施例3] [Example 3]
使用了具備:設有第6圖所示的一對直線型 移動磁場發生裝置42的連續鑄造用鑄模40之鋼胚連續鑄造機,進行鑄造約300(ton)的鋁(脫氧)鎮靜熔鋼的鑄造試驗。所鑄造的鋼胚鑄片的厚度是250(mm),寬度是1600(mm),熔鋼注入流量是5.0~6.0(ton/min)。所使用的兩孔式浸漬式噴嘴的吐出孔的吐出角度係朝下方25(°),浸漬式噴嘴的浸漬深度(從鑄模內熔鋼湯面起迄吐出孔上端為止的距離)是180(mm)以上且未達300(mm)。浸漬式噴嘴的吐出孔的形狀是每一邊的長度為70(mm)的正方形,浸漬式噴嘴的內徑是70(mm)。從浸漬式噴嘴吹入的鈍氣係使用了氬氣。並且將熔鋼吞吐量P與氬氣流量A的比值A/P設定在2.0~3.5(NL/ton)的範圍。由磁極施加交流移動磁場,在對於熔鋼吐出流進行制動的條件下,實施了鑄造。 Used: equipped with a pair of straight lines as shown in Figure 6 The steel preform continuous casting machine for the continuous casting mold 40 of the moving magnetic field generating device 42 was subjected to a casting test for casting aluminum (deoxidized) killed molten steel of about 300 (ton). The cast steel slab has a thickness of 250 (mm), a width of 1600 (mm), and a molten steel injection flow rate of 5.0 to 6.0 (ton/min). The discharge angle of the discharge hole of the two-hole type immersion nozzle used is 25 (°) downward, and the immersion depth of the immersion nozzle (the distance from the molten steel soup surface in the mold to the upper end of the discharge hole) is 180 (mm). Above and less than 300 (mm). The shape of the discharge hole of the immersion nozzle is a square having a length of 70 (mm) on each side, and the inner diameter of the immersion nozzle is 70 (mm). The blunt gas blown from the immersion nozzle used argon gas. Further, the ratio A/P of the molten steel throughput P to the argon flow rate A is set in the range of 2.0 to 3.5 (NL/ton). The alternating magnetic field is applied by the magnetic pole, and casting is performed under the condition that the molten steel discharge flow is braked.
針對於所鑄造出來的鋼胚鑄片,依序實施:熱軋、冷軋、合金化熔融鍍鋅處理,使用線上(on line)表面缺陷計連續地測定這種合金化熔融鍍鋅鋼板的表面缺陷,再從所測定到的結果當中,藉由觀察缺陷的外觀以及進行SEM分析、ICP分析等項目,來判別出:製鋼性的缺陷(由鋼胚鑄片的夾雜物所引起的缺陷),再以合金化熔融鍍鋅鋼板之每100(m)長度中的缺陷個數(也稱為「製品缺陷指數」)來進行評比。表3中係顯示本發明例30~49的鑄造條件以及製品缺陷指數的調查結果。在表3中也是同樣地,對角線方向角度θ,係將小數點第2位予以四捨五入而計算出來的。又,表3中所記載的對角線方向角度 θ的數值,係將小數點第2位予以四捨五入後的數值。又,「α-θ」的數值,係將小數點第1位予以四捨五入後的數值。第24圖係顯示本發明例39~49之「α-θ」與「製品缺陷指數」的關係的圖。 For the cast steel slabs, the steel slabs are sequentially processed: hot rolling, cold rolling, alloying hot galvanizing, and the surface of the alloyed galvanized steel sheet is continuously measured using an on line surface defect meter. Defects, and from the measured results, by observing the appearance of the defects and performing SEM analysis, ICP analysis, and the like, it is determined that the steel defects (defects caused by the inclusions of the steel slabs), The number of defects per 100 (m) length of the alloyed hot-dip galvanized steel sheet (also referred to as "product defect index") was evaluated. Table 3 shows the results of investigations on the casting conditions and the product defect index of Examples 30 to 49 of the present invention. Similarly in Table 3, the diagonal direction angle θ is calculated by rounding off the second decimal place. Also, the diagonal direction angles shown in Table 3 The value of θ is the value obtained by rounding off the second decimal place. Further, the value of "α-θ" is a value obtained by rounding off the first decimal place. Fig. 24 is a graph showing the relationship between "α-θ" and "product defect index" in Examples 39 to 49 of the present invention.
此外,在表3中雖然並未記載,但是,也確認出來:利用同樣的流動控制方式,但並未使浸漬式噴嘴吐出孔呈傾斜而是朝向短邊的情況下,製品缺陷指數是昇高到達0.51~0.56(個/100m)。 In addition, although it is not described in Table 3, it is confirmed that the same flow control method is used, but the impregnation nozzle discharge hole is not inclined but is directed to the short side, and the product defect index is increased. It reaches 0.51~0.56 (pieces/100m).
本發明例39~44是將「α-θ」設定在2~7(°)的範圍內。如第24圖所示,在這種情況下,製品缺陷指數是降低到0.22~0.24(個/100m)。換言之,可得知:在設有直線型移動磁場發生裝置,一面對於熔鋼流進行制動一面控制流動的情況下,係將傾斜角度α(°)設定在「θ+2」以上且「θ+7」以下的範圍內為宜。 In the inventive examples 39 to 44, "α-θ" was set in the range of 2 to 7 (°). As shown in Fig. 24, in this case, the product defect index is reduced to 0.22 to 0.24 (pieces/100 m). In other words, when the linear moving magnetic field generating device is provided and the flow is controlled while braking the molten steel flow, the inclination angle α (°) is set to be "θ + 2" or more and "θ + 7" is within the following range.
另一方面,本發明例45~47則是將「α-θ」設定在-6~0(°)的範圍內。在這種情況下,製品缺陷指數是稍微昇高到0.27~0.29(個/100m)。其原因被推定 為:賦予熔鋼流的流速稍微變小的結果,但這些例子也都是充分良質的鋼胚。又,本發明例48~49是將「α-θ」設定在8~10(°)的範圍內。在這種情況下,製品缺陷指數稍微昇高成0.27~0.28(個/100m)。其原因被推定為:賦予熔鋼流的流速稍微變大,因而助長了鑄模粉被捲入的結果,但這些例子也都是充分良質的鋼胚。此外,針對這些鋼胚的鑄片剖面進行了調查之結果,雖然也可以看到在鑄模內的凝固鑄片外殼的成長厚度有稍薄一點的地方,但並未達到可能會阻礙作業穩定性的程度。 On the other hand, in the present invention examples 45 to 47, "α-θ" is set in the range of -6 to 0 (°). In this case, the product defect index is slightly increased to 0.27~0.29 (pieces/100m). The reason is presumed It is the result that the flow rate of the molten steel flow is slightly reduced, but these examples are also sufficiently good quality steel embryos. Further, in Examples 48 to 49 of the present invention, "α-θ" was set in the range of 8 to 10 (°). In this case, the product defect index is slightly increased to 0.27 to 0.28 (pieces/100 m). The reason for this is presumed to be that the flow rate to the molten steel flow is slightly increased, thereby contributing to the fact that the mold powder is entrapped, but these examples are also sufficiently good quality steel embryos. In addition, as a result of investigating the profile of the slabs of these steel slabs, it is also possible to see that the growth thickness of the solidified slab shell in the mold is slightly thinner, but it does not reach a situation that may hinder the stability of the work. degree.
此外,在本實施例中雖然未記載,但是,也確認出來:即使將來自浸漬式噴嘴的熔鋼吐出流予以加速的情況下,也具有同樣的傾向。而且也又另外確認出來:在所鑄造的鋼胚鑄片的厚度為220~300(mm)的範圍,鑄造寬度為1000~2000(mm),熔鋼吞吐量為3.0~8.0的範圍的情況下,亦可獲得本實施例所記載的例子同等程度的效果。此外,也確認出來:在浸漬式噴嘴的熔鋼吐出角度為15~35(°)的範圍亦可獲得同樣的傾向。其他,關於浸漬式噴嘴的吐出孔的形狀和浸漬式噴嘴的內徑,並不是只限定本實施例所記載的條件,只要是本行業者所能想到的範圍內的話,也都無妨。 Further, although not described in the present embodiment, it has been confirmed that even when the molten steel discharge flow from the immersion nozzle is accelerated, the same tendency is obtained. Moreover, it has been confirmed separately: in the case where the thickness of the cast steel slab is 220 to 300 (mm), the casting width is 1000 to 2000 (mm), and the molten steel throughput is in the range of 3.0 to 8.0. The same effects as those of the examples described in the examples can be obtained. Further, it was confirmed that the same tendency was obtained in the range in which the molten steel discharge angle of the immersion nozzle was 15 to 35 (°). In addition, the shape of the discharge hole of the immersion nozzle and the inner diameter of the immersion nozzle are not limited to the conditions described in the present embodiment, and may be any extent as long as it is within the range that can be considered by those skilled in the art.
[實施例4] [Example 4]
使用了具有:具備如第8圖所示的一對磁極52的連續鑄造用鑄模50之鋼胚連續鑄造機,進行鑄造約 300(ton)的鋁(脫氧)鎮靜熔鋼的鑄造試驗。所鑄造的鋼胚鑄片的厚度是260(mm),寬度是1600(mm),熔鋼注入流量是5.0~6.0(ton/min)。所使用的兩孔式浸漬式噴嘴的吐出孔的吐出角度是朝下方25(°),浸漬式噴嘴的浸漬深度(從鑄模內熔鋼湯面起迄吐出孔上端為止的距離)是180(mm)以上且未達300(mm)。浸漬式噴嘴的吐出孔的形狀是每一邊的長度為70(mm)的正方形,浸漬式噴嘴的內徑是70(mm)。從浸漬式噴嘴吹入的鈍氣是使用氬氣。熔鋼吞吐量P與氬氣流量A的比值A/P,是設定成落在2.0~3.5(NL/ton)的範圍內。在交流移動磁場強度為300~1000(Gs)的範圍內,改變交流移動磁場強度X與所鑄造的鋼胚鑄片的寬度W的比值X/W(Gs/mm),以及來自浸漬式噴嘴的吐出流的傾斜角度α,實施了鑄造。 A steel slab continuous casting machine having a continuous casting mold 50 having a pair of magnetic poles 52 as shown in Fig. 8 is used for casting. Casting test of 300 (ton) aluminum (deoxidized) killed molten steel. The cast steel slab has a thickness of 260 (mm), a width of 1600 (mm), and a molten steel injection flow rate of 5.0 to 6.0 (ton/min). The discharge angle of the discharge hole of the two-hole type immersion nozzle used is 25 (°) downward, and the immersion depth of the immersion nozzle (the distance from the molten steel soup surface in the mold to the upper end of the discharge hole) is 180 (mm). Above and less than 300 (mm). The shape of the discharge hole of the immersion nozzle is a square having a length of 70 (mm) on each side, and the inner diameter of the immersion nozzle is 70 (mm). The blunt gas blown from the immersion nozzle is argon gas. The ratio A/P of the molten steel throughput P to the argon flow rate A is set to fall within the range of 2.0 to 3.5 (NL/ton). In the range of the AC moving magnetic field strength of 300 to 1000 (Gs), the ratio X/W (Gs/mm) of the AC moving magnetic field strength X to the width W of the cast steel slab is changed, and the immersion nozzle is used. The casting angle was performed by the inclination angle α of the discharge flow.
針對於所鑄造出來的鋼胚鑄片,依序實施:熱軋、冷軋、合金化熔融鍍鋅處理,使用線上(on line)表面缺陷計連續地測定這種合金化熔融鍍鋅鋼板的表面缺陷,再從所測定到的結果當中,藉由觀察缺陷的外觀以及進行SEM分析、ICP分析等項目,來判別出:製鋼性的缺陷(由鋼胚鑄片的夾雜物所引起的缺陷),再以合金化熔融鍍鋅鋼板之每100(m)長度中的缺陷個數(也稱為「製品缺陷指數」)來進行評比。表4係顯示本發明例50~71的鑄造條件以及製品缺陷指數的調查結果。在表4中也是同樣地,對角線方向角度θ,係將小數點第2位予以四捨五入而計算出來的。又,表4中所記載的對角線方向角度θ 的數值,係將小數點第2位予以四捨五入後的數值。又,「α-θ」的數值,係將小數點第1位予以四捨五入後的數值。在比較例33~37中也記載出將吐出孔朝向迴旋流的下流側的傾斜角度。第25圖係顯示將本發明例50~71之「α-θ」與「製品缺陷指數」的關係,以X/W的比值0.45為境界予以分區顯示的圖。 For the cast steel slabs, the steel slabs are sequentially processed: hot rolling, cold rolling, alloying hot galvanizing, and the surface of the alloyed galvanized steel sheet is continuously measured using an on line surface defect meter. Defects, and from the measured results, by observing the appearance of the defects and performing SEM analysis, ICP analysis, and the like, it is determined that the steel defects (defects caused by the inclusions of the steel slabs), The number of defects per 100 (m) length of the alloyed hot-dip galvanized steel sheet (also referred to as "product defect index") was evaluated. Table 4 shows the results of investigations on the casting conditions and the product defect index of Examples 50 to 71 of the present invention. Similarly in Table 4, the diagonal direction angle θ is calculated by rounding off the second decimal place. Further, the diagonal direction angle θ described in Table 4 The value is the value obtained by rounding off the second decimal place. Further, the value of "α-θ" is a value obtained by rounding off the first decimal place. In Comparative Examples 33 to 37, the inclination angle of the discharge hole toward the downstream side of the swirling flow is also described. Fig. 25 is a view showing the relationship between "α-θ" and "product defect index" of Examples 50 to 71 of the present invention, and the partition is displayed with a ratio of X/W of 0.45.
此外,表4中雖然並未記載,但是,也確認出來:利用同樣的流動控制方式,但並未使浸漬式噴嘴吐出孔呈傾斜而是朝向短邊的情況下,製品缺陷指數是昇高到達0.45~0.51(個/100m)。 In addition, although it is not described in Table 4, it is confirmed that the same flow control method is used, but the impregnation nozzle discharge hole is not inclined but is directed to the short side, and the product defect index is increased and reached. 0.45~0.51 (pieces/100m).
本發明例50~60係將X/W的比值(Gs/mm)設 定在0.30以上且未達0.45的情況。如第25圖所示,可以得知:在這種情況下,藉由將「α-θ」設定在-3~0(°)的範圍內,可使製品缺陷指數降到特別低的0.18~0.20(個/100m)。換言之,可以得知:X/W的比值(Gs/mm)是0.30以上且未達0.45的情況下,係將傾斜角度α(°)設定在「θ-3」以上且「θ」以下的範圍內為宜。 In the examples 50 to 60 of the present invention, the ratio of X/W (Gs/mm) is set. It is set at 0.30 or more and does not reach 0.45. As shown in Fig. 25, it can be known that in this case, by setting "α-θ" in the range of -3 to 0 (°), the defect index of the product can be reduced to a particularly low 0.18~ 0.20 (pieces / 100m). In other words, when the ratio (Gs/mm) of X/W is 0.30 or more and less than 0.45, the inclination angle α (°) is set to a range of "θ-3" or more and "θ" or less. The inside is appropriate.
另一方面,本發明例61~71係將X/W的比值(Gs/mm)設定在0.45以上且未達0.55。可以得知:在這種情況下,藉由將「α-θ」設定在-6~-4(°)的範圍內,可使製品缺陷指數降到特別低的0.18~0.20(個/100m)。換言之,可以得知:X/W的比值(Gs/mm)是0.45以上且未達0.55的情況下,係將傾斜角度α(°)設定在「θ-6」以上且「θ-4」以下的範圍內為宜。其原因被推定為:藉由配合X/W的比值來設定合適的傾斜角度,可將熔鋼流控制得很良好所致的結果。其他的本發明例亦可獲得充分良質的鋼胚。 On the other hand, in the inventive examples 61 to 71, the X/W ratio (Gs/mm) was set to 0.45 or more and less than 0.55. It can be known that in this case, by setting "α-θ" in the range of -6~-4 (°), the defect index of the product can be reduced to a particularly low 0.18~0.20 (pieces/100m). . In other words, when the ratio (Gs/mm) of X/W is 0.45 or more and less than 0.55, the inclination angle α (°) is set to be "θ-6" or more and "θ-4" or less. The scope is appropriate. The reason for this is presumed to be that the result of controlling the flow of the molten steel is good by setting the appropriate inclination angle in accordance with the ratio of X/W. Other examples of the present invention can also obtain sufficiently good quality steel embryos.
另一方面,如比較例33~37所示,如果將吐出流朝向迴旋流的下游側的話,製品缺陷指數明顯升高為0.65~0.68(個/100m)。其原因被推定:是因為助長了迴旋流與反轉流發生衝突和干擾的結果。 On the other hand, as shown in Comparative Examples 33 to 37, if the discharge flow was directed to the downstream side of the swirling flow, the product defect index was remarkably increased to 0.65 to 0.68 (pieces/100 m). The reason for this is presumed: it is the result of the conflict and interference between the swirling flow and the reverse flow.
此外,在本實施例中雖然未記載,但是,也確認出來:即使在所鑄造的鋼胚鑄片的厚度為220~300(mm)的範圍,鑄造寬度為1000~2000(mm),熔鋼吞吐量為3.0~8.0的範圍的情況下,亦可獲得本實施例所記載 的例子同等程度的效果。此外,也確認出來:在浸漬式噴嘴的熔鋼吐出角度為15~35(°)的範圍亦可獲得同樣的傾向。其他,關於浸漬式噴嘴的吐出孔的形狀和浸漬式噴嘴的內徑,並不是只限定本實施例所記載的條件,只要是本行業者所能想到的範圍內的話,也都無妨。 Further, although not described in the present embodiment, it has been confirmed that even in the range of the cast steel slab having a thickness of 220 to 300 (mm), the casting width is 1000 to 2000 (mm), and the molten steel When the throughput is in the range of 3.0 to 8.0, the present embodiment can also be obtained. The example has the same effect. Further, it was confirmed that the same tendency was obtained in the range in which the molten steel discharge angle of the immersion nozzle was 15 to 35 (°). In addition, the shape of the discharge hole of the immersion nozzle and the inner diameter of the immersion nozzle are not limited to the conditions described in the present embodiment, and may be any extent as long as it is within the range that can be considered by those skilled in the art.
[實施例5] [Example 5]
使用了具備:具有第12圖所示的一對上部磁極6與一對下部磁極7的連續鑄造用鑄模1之鋼胚連續鑄造機,進行鑄造約300(ton)的鋁(脫氧)鎮靜熔鋼的鑄造試驗。所鑄造的鋼胚鑄片的厚度是260(mm),寬度是1000~1900(mm),熔鋼注入流量是4.0~7.5(ton/min)。所使用的兩孔式浸漬式噴嘴的吐出孔的吐出角度(水平時係視為零度角度)係朝下方25°,浸漬式噴嘴的浸漬深度(從鑄模內熔鋼湯面起迄吐出孔上端為止的距離)是180(mm)以上且未達300(mm)。浸漬式噴嘴的吐出孔的形狀是每一邊的長度為80(mm)的正方形,浸漬式噴嘴的內徑是80(mm)。從浸漬式噴嘴吹入的鈍氣係使用氬氣。熔鋼吞吐量P與氬氣流量A的比值A/P係是設定成落在2.0~3.5(NL/ton)的範圍內。 A steel continuous casting machine having a continuous casting mold 1 having a pair of upper magnetic poles 6 and a pair of lower magnetic poles 7 shown in Fig. 12 was used, and aluminum (deoxidized) killed molten steel of about 300 (ton) was cast. Casting test. The cast steel slab has a thickness of 260 (mm), a width of 1000 to 1900 (mm), and a molten steel injection flow rate of 4.0 to 7.5 (ton/min). The discharge angle of the discharge hole of the two-hole type immersion nozzle used (the angle is regarded as a zero degree in the horizontal direction) is 25° below, and the immersion depth of the immersion nozzle (from the molten steel soup surface in the mold to the upper end of the discharge hole) The distance) is 180 (mm) or more and less than 300 (mm). The shape of the discharge hole of the immersion nozzle is a square having a length of 80 (mm) on each side, and the inner diameter of the immersion nozzle is 80 (mm). Argon gas is used as the blunt gas blown from the immersion nozzle. The ratio A/P of the molten steel throughput P to the argon flow rate A is set to fall within the range of 2.0 to 3.5 (NL/ton).
來自浸漬式噴嘴的吐出流的吐出方向係區分成:朝向由交流移動磁場所形成的迴旋流的上游側、迴旋流的下游側、以及與鑄模長邊呈平行的方向(與鑄模短邊呈垂直的方向)之三種。即使將吐出流的吐出方向朝向迴 旋流的上游側及迴旋流的下游側傾斜的情況下,也是將傾斜角度α予以改變。此外,也分別改變由上部磁極所施加的交流移動磁場、由上部磁極所施加的直流靜磁場、以及由下部磁極所施加的直流靜磁場的強度,來實施了鑄造。 The discharge direction of the discharge flow from the immersion nozzle is divided into: an upstream side of the swirling flow formed by the alternating magnetic field, a downstream side of the swirling flow, and a direction parallel to the long side of the mold (vertical to the short side of the mold) The direction of the three). Even if the spit out direction of the spit out is directed back When the upstream side of the swirling flow and the downstream side of the swirling flow are inclined, the inclination angle α is also changed. Further, casting was also performed by changing the intensity of the alternating current moving magnetic field applied by the upper magnetic pole, the direct current static magnetic field applied by the upper magnetic pole, and the direct current static magnetic field applied by the lower magnetic pole.
針對於所鑄造出來的鋼胚鑄片,依序實施:熱軋、冷軋、合金化熔融鍍鋅處理,使用線上(on line)表面缺陷計連續地測定這種合金化熔融鍍鋅鋼板的表面缺陷,再從所測定到的結果當中,藉由觀察缺陷的外觀以及進行SEM分析、ICP分析等項目,來判別出:製鋼性的缺陷(由鋼胚鑄片的夾雜物所引起的缺陷),再以合金化熔融鍍鋅鋼板之每100(m)長度中的缺陷個數(也稱為「製品缺陷指數」)來進行評比。表5係顯示本發明例72~79以及比較例38~46的鑄造條件以及製品缺陷指數的調查結果。表5中,對角線方向角度θ以及傾斜角度α,係將小數點第2位予以四捨五入計算而得的數值。 For the cast steel slabs, the steel slabs are sequentially processed: hot rolling, cold rolling, alloying hot galvanizing, and the surface of the alloyed galvanized steel sheet is continuously measured using an on line surface defect meter. Defects, and from the measured results, by observing the appearance of the defects and performing SEM analysis, ICP analysis, and the like, it is determined that the steel defects (defects caused by the inclusions of the steel slabs), The number of defects per 100 (m) length of the alloyed hot-dip galvanized steel sheet (also referred to as "product defect index") was evaluated. Table 5 shows the results of investigations on casting conditions and product defect indexes of Inventive Examples 72 to 79 and Comparative Examples 38 to 46. In Table 5, the diagonal direction angle θ and the inclination angle α are values obtained by rounding off the second decimal place.
如表5所示,係將由上部磁極所施加的交流移動磁場的強度控制在500~900(Gs)的範圍內;將由上部磁極所施加的直流靜磁場的強度控制在2000~3300(Gs)的範圍內;將由下部磁極所施加的直流靜磁場的強度控制在3000~4500(Gs)的範圍內,來進行連續鑄造。此外,雖然在表5中並未記載,但是,也確認出來:當由上部磁極以及下部磁極所施加的直流靜磁場的強度,落在這些範圍之外的情況下,全部都是製品缺陷指數偏高的結果。此外,雖然在表5中並未記載,但是,也確認出來:上部磁極的交流移動磁場的強度X與鋼胚鑄片的寬度W的比值X/W未達0.30的情況下,製品缺陷指數也偏高。 As shown in Table 5, the intensity of the AC moving magnetic field applied by the upper magnetic pole is controlled within a range of 500 to 900 (Gs); and the intensity of the DC static magnetic field applied by the upper magnetic pole is controlled at 2000 to 3300 (Gs). Within the range; the strength of the DC static magnetic field applied by the lower magnetic pole is controlled within a range of 3000 to 4500 (Gs) for continuous casting. Further, although not described in Table 5, it is also confirmed that when the intensity of the DC static magnetic field applied by the upper magnetic pole and the lower magnetic pole falls outside these ranges, all of them are product defect index deviations. High results. In addition, although it is not described in Table 5, it is also confirmed that when the ratio X/W of the intensity X of the AC moving magnetic field of the upper magnetic pole to the width W of the steel slab is less than 0.30, the product defect index is also High.
表5中係記載出:依據所鑄造的鑄片厚度D與鑄片寬度W而計算出來的對角線方向角度θ、以及鑄造時的吐出流的傾斜角度α。此外,對角線方向角度θ係將小數點第2位予以四捨五入的數值。 In Table 5, the diagonal direction angle θ calculated based on the cast slab thickness D and the slab width W, and the inclination angle α of the discharge flow at the time of casting are described. Further, the diagonal direction angle θ is a value obtained by rounding off the second decimal place.
本發明例72~79係將來自浸漬式噴嘴的吐出流朝向由交流移動磁場所形成的迴旋流的上游側傾斜。這種情況下的製品缺陷指數係降到0.12~0.25(個/100m),可獲得良好的結果。 In the examples 72 to 79 of the present invention, the discharge flow from the immersion nozzle was inclined toward the upstream side of the swirling flow formed by the alternating current moving magnetic field. In this case, the product defect index is reduced to 0.12 to 0.25 (pieces/100 m), and good results are obtained.
相對於此,比較例38~41則並未將吐出方向予以傾斜。這種情況的製品缺陷指數是0.35~0.42(個/100m),高於本發明例72~79。又,比較例42~43係將浸漬式噴嘴的吐出方向朝向交流移動磁場所形成的迴旋流的下游側傾斜。可確認出:這種情況的製品缺陷指數是 0.55~0.58(個/100m),呈現大幅度惡化。其原因被推定:是因為助長了在迴旋流的下游側的迴旋流與反轉流發生衝突和干擾的結果。 On the other hand, in Comparative Examples 38 to 41, the discharge direction was not inclined. The product defect index in this case is 0.35 to 0.42 (pieces/100 m), which is higher than the examples 72 to 79 of the present invention. Further, in Comparative Examples 42 to 43, the discharge direction of the immersion nozzle was inclined toward the downstream side of the swirling flow formed by the AC moving magnetic field. It can be confirmed that the product defect index of this case is 0.55~0.58 (pieces/100m), showing a significant deterioration. The reason for this is presumed: it is because the result of the collision and interference between the swirling flow and the reverse flow on the downstream side of the swirling flow is promoted.
本發明例80~82係將上部磁極的交流移動磁場的強度X與鋼胚鑄片的寬度W的比值X/W(Gs/mm)設定在0.55以上。這種情況的製品缺陷指數是0.30~0.32(個/100m),稍微高於本發明例72~79。其原因被推定:是因為相對於寬度W的交流移動磁場強度X太強,因而鑄模內的熔鋼流動稍微變得不穩定所致。 In the examples 80 to 82 of the present invention, the ratio X/W (Gs/mm) of the intensity X of the AC moving magnetic field of the upper magnetic pole to the width W of the steel slab is set to 0.55 or more. The product defect index in this case was 0.30 to 0.32 (pieces/100 m), which was slightly higher than the examples 72 to 79 of the present invention. The reason for this is presumed: it is because the AC moving magnetic field strength X with respect to the width W is too strong, and thus the molten steel flow in the mold is slightly unstable.
此外,在本實施例中雖然未記載,但是,也確認出來:即使在所鑄造的鋼胚鑄片的厚度為220~300(mm)的範圍內的情況下,亦可獲得本實施例所記載的例子同等程度的效果。此外,關於浸漬式噴嘴的吐出孔的形狀和浸漬式噴嘴的內徑,並不是只限定本實施例所記載的條件,只要是本行業者所能想到的範圍內的話,也都無妨。 Further, although not described in the present embodiment, it has been confirmed that even in the case where the thickness of the cast steel slab is in the range of 220 to 300 (mm), the present embodiment can be obtained. The example has the same effect. Further, the shape of the discharge hole of the immersion nozzle and the inner diameter of the immersion nozzle are not limited to the conditions described in the examples, and may be any extent as long as they are within the range that can be considered by those skilled in the art.
[實施例6] [Embodiment 6]
與實施例5同樣地,使用了具有:具備如第12圖所示的上下兩段磁極的連續鑄造用鑄模1之鋼胚連續鑄造機,進行了用來鑄造約300(ton)鋁(脫氧)鎮淨熔鋼的鑄造試驗。所鑄造的鋼胚鑄片的厚度是260(mm),寬度是1600~1700(mm),熔鋼注入流量是6.0~7.0(ton/min)。所使用的兩孔式浸漬式噴嘴的吐出孔的吐出角度是朝下方25(°),浸漬式噴嘴的浸漬深度(從鑄模內熔鋼 湯面起迄吐出孔上端為止的距離)是180(mm)以上且未達300(mm)。浸漬式噴嘴的吐出孔的形狀是每一邊的長度為80(mm)的正方形,浸漬式噴嘴的內徑是80(mm)。從浸漬式噴嘴吹入的鈍氣是使用氬氣。 In the same manner as in the fifth embodiment, a steel continuous casting machine having a casting mold 1 for continuous casting having the upper and lower magnetic poles as shown in Fig. 12 was used, and was cast for about 300 (ton) aluminum (deoxidation). Casting test of Zhenjing molten steel. The cast steel slab has a thickness of 260 (mm), a width of 1600 to 1700 (mm), and a molten steel injection flow rate of 6.0 to 7.0 (ton/min). The discharge angle of the discharge hole of the two-hole type immersion nozzle used is 25 (°) downward, and the immersion depth of the immersion nozzle (from the molten steel in the mold) The distance from the top of the soup to the upper end of the hole is 180 (mm) or more and less than 300 (mm). The shape of the discharge hole of the immersion nozzle is a square having a length of 80 (mm) on each side, and the inner diameter of the immersion nozzle is 80 (mm). The blunt gas blown from the immersion nozzle is argon gas.
實施例6係將來自浸漬式噴嘴的吐出方向,朝向由交流移動磁場所形成的迴旋流的上游側傾斜。此外,將施加於上部磁極的交流移動磁場的強度控制在500~900(Gs)的範圍內,將施加於上部磁極的直流靜磁場的強度控制在2000~3300(Gs)的範圍內,將施加於下部磁極的直流靜磁場的強度控制在3000~4500(Gs)的範圍內,並且改變交流移動磁場強度X與所鑄造的鋼胚鑄片的寬度W的比值X/W(Gs/mm)以及來自浸漬式噴嘴的吐出流的傾斜角度α,而實施了鑄造。 In the sixth embodiment, the discharge direction from the immersion nozzle is inclined toward the upstream side of the swirling flow formed by the alternating current moving magnetic field. Further, the intensity of the AC moving magnetic field applied to the upper magnetic pole is controlled within a range of 500 to 900 (Gs), and the intensity of the DC static magnetic field applied to the upper magnetic pole is controlled within a range of 2000 to 3300 (Gs), which is applied. The intensity of the DC static magnetic field at the lower magnetic pole is controlled within the range of 3000 to 4500 (Gs), and the ratio X/W (Gs/mm) of the AC moving magnetic field strength X to the width W of the cast steel slab is changed and Casting was carried out by the inclination angle α of the discharge flow from the immersion nozzle.
針對於所鑄造出來的鋼胚鑄片,依序實施:熱軋、冷軋、合金化熔融鍍鋅處理,使用線上(on line)表面缺陷計連續地測定這種合金化熔融鍍鋅鋼板的表面缺陷,再從所測定到的結果當中,藉由觀察缺陷的外觀以及進行SEM分析、ICP分析等項目,來判別出:製鋼性的缺陷(由鋼胚鑄片的夾雜物所引起的缺陷),再以合金化熔融鍍鋅鋼板之每100(m)長度中的缺陷個數(也稱為「製品缺陷指數」)來進行評比。表6係顯示本發明例80~103的鑄造條件以及製品缺陷指數的調查結果。表6中的對角線方向角度θ的數值是將小數點第2位予以四捨五入的數值;「α-θ」的數值係將小數點第1位予以四捨五入的 數值。此外,第26圖係將本發明例83~106之「α-θ」與「製品缺陷指數」的關係,以X/W的比值0.45作為境界予以分區顯示的圖。 For the cast steel slabs, the steel slabs are sequentially processed: hot rolling, cold rolling, alloying hot galvanizing, and the surface of the alloyed galvanized steel sheet is continuously measured using an on line surface defect meter. Defects, and from the measured results, by observing the appearance of the defects and performing SEM analysis, ICP analysis, and the like, it is determined that the steel defects (defects caused by the inclusions of the steel slabs), The number of defects per 100 (m) length of the alloyed hot-dip galvanized steel sheet (also referred to as "product defect index") was evaluated. Table 6 shows the results of investigations on the casting conditions and the defect index of the products of Examples 80 to 103 of the present invention. The value of the diagonal direction angle θ in Table 6 is the value that rounds off the second decimal place; the value of "α-θ" is rounded off the first decimal place. Value. Further, Fig. 26 is a diagram showing the relationship between "α-θ" and "product defect index" of Examples 83 to 106 of the present invention, and the ratio of X/W is 0.45 as a boundary.
本發明例83~94係將X/W的比值(Gs/mm)設定在0.30以上且未達0.45。如第26圖所示,可以得知:在這種情況下,藉由將「α-θ」設定在-2°~5°的範圍內,可使得製品缺陷指數降到特別低的0.13~0.15(個/100m)。換言之,可以得知:在X/W的比值(Gs/mm)為0.30以上且未達0.45的情況下,係將傾斜角度α(°)設定在「θ-2」以上且「θ+5」以下的範圍內為宜。 In Examples 83 to 94 of the present invention, the X/W ratio (Gs/mm) was set to 0.30 or more and less than 0.45. As shown in Fig. 26, it can be known that in this case, by setting "α-θ" in the range of -2° to 5°, the defect index of the product can be reduced to a particularly low level of 0.13 to 0.15. (one / 100m). In other words, when the ratio (Gs/mm) of X/W is 0.30 or more and less than 0.45, the inclination angle α (°) is set to be "θ-2" or more and "θ+5". The following ranges are appropriate.
另一方面,可以得知:本發明例95~106係在X/W的比值(Gs/mm)為0.45以上且未達0.55的條件 下,此時的「α-θ」在-5~2(°)的範圍內的話,製品缺陷指數降到特別低的0.13~0.15(個/100m)。換言之,當X/W的比值(Gs/mm)為0.45以上且未達0.55的情況下,係將傾斜角度α(°)設定在「θ-5」以上且「θ+2」以下的範圍內為宜。 On the other hand, it can be understood that the examples 95 to 106 of the present invention have a ratio of X/W (Gs/mm) of 0.45 or more and less than 0.55. When the "α-θ" at this time is in the range of -5 to 2 (°), the product defect index falls to a particularly low level of 0.13 to 0.15 (pieces/100 m). In other words, when the ratio (Gs/mm) of X/W is 0.45 or more and less than 0.55, the inclination angle α (°) is set within a range of “θ-5” or more and “θ+2” or less. It is appropriate.
此外,在表6中,雖然只是記載出鋼胚鑄片的厚度和寬度落在某一定範圍內的例子而已,但是,也確認出來:例如鋼胚鑄片的厚度在220~300(mm)的範圍內,鋼胚鑄片的寬度在1000~2000(mm)的範圍內,也具有同等程度的效果。 Further, in Table 6, although only the example in which the thickness and the width of the steel slab are within a certain range is described, it is also confirmed that, for example, the thickness of the steel slab is 220 to 300 (mm). Within the range, the width of the steel slab is in the range of 1000 to 2000 (mm), and has the same degree of effect.
2‧‧‧鑄模長邊 2‧‧‧Molded long side
3‧‧‧鑄模短邊 3‧‧‧Molded short side
4‧‧‧浸漬式噴嘴 4‧‧‧Dip nozzle
5‧‧‧吐出孔 5‧‧‧Spit hole
8‧‧‧熔鋼 8‧‧‧Fused steel
9‧‧‧凝固鑄片外殼 9‧‧‧ Solidified cast shell
10‧‧‧鑄模內熔鋼湯面 10‧‧‧Molded steel noodle soup in mold
11‧‧‧吐出流 11‧‧‧Spit out
20‧‧‧連續鑄造用鑄模 20‧‧‧Continuous casting mold
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