JP6198648B2 - Ingot casting method - Google Patents
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- JP6198648B2 JP6198648B2 JP2014056647A JP2014056647A JP6198648B2 JP 6198648 B2 JP6198648 B2 JP 6198648B2 JP 2014056647 A JP2014056647 A JP 2014056647A JP 2014056647 A JP2014056647 A JP 2014056647A JP 6198648 B2 JP6198648 B2 JP 6198648B2
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- 238000000034 method Methods 0.000 title claims description 28
- 238000002347 injection Methods 0.000 claims description 106
- 239000007924 injection Substances 0.000 claims description 106
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 43
- 229910000831 Steel Inorganic materials 0.000 description 39
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- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
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Description
本発明は、鋳型の配列が非対称である下注造塊装置において下注ぎ鋳造を行う下注造塊方法に関する。 The present invention relates to a lower casting ingot method for performing lower casting in a lower casting ingot apparatus having an asymmetrical arrangement of molds.
通常、下注造塊装置においては、取鍋からの溶鋼を注入する注入管を基準にすると、当該注入管に対して、左右対称に鋳型を配列して鋳造を行うことが多いが、取鍋の溶鋼重量と、鋳造する1つの鋼塊重量と兼ね合いによっては、左側に2基の鋳型、右側に1基の鋳型というように、非対称に鋳型を配置しなければならない場合がある。このように、非対称に鋳型を配置した場合、各鋳型内で湯上がり速度が異なるため、右側の鋳型の湯面が左側の鋳型の湯面よりも高くなり、鋳型間での湯面の高さが異なってしまう。 Usually, in a pouring ingot device, when an injection pipe for injecting molten steel from a ladle is used as a reference, casting is often performed by arranging molds symmetrically with respect to the injection pipe. Depending on the weight of the molten steel and the weight of one ingot to be cast, there are cases where the molds must be arranged asymmetrically, such as two molds on the left side and one mold on the right side. In this way, when the molds are arranged asymmetrically, since the hot water rising speed is different in each mold, the molten metal surface of the right mold is higher than the molten metal surface of the left mold, and the molten metal height between the molds is high. It will be different.
このようなことから、例えば、湯面が同じ高さとなるまで溶鋼の注入を中断したり、取鍋のノズルを絞って溶鋼の注入速度を極端に少なくすることで湯面の高い鋳型内の溶鋼を湯道に逆流させることにより、鋳型間での湯面の高さを均一化をしている。
しかしながら、このような方法では、注湯速度の制御が非常に大変であると共に、注湯時間が長くなり、作業効率が低下してしまう。また、溶鋼を湯道に逆流させる方法を行った場合は、湯道内に残留していた溶損した耐火物などがゆっくりとした流れで他の鋳型内に持ち込まれると共に、持ち込まれた耐火物は鋳型内で浮上することが難しいため、鋼塊のボトム部に容易に捕捉されて、介在物による欠陥が発生してしまう虞がある。
For this reason, for example, the molten steel in the mold with a high molten metal surface can be reduced by interrupting the molten steel injection until the molten metal surface is at the same height, or by squeezing the ladle nozzle to extremely reduce the molten steel injection speed. The height of the hot water surface between the molds is made uniform by allowing the water to flow back to the runner.
However, in such a method, it is very difficult to control the pouring speed, and the pouring time becomes long and the working efficiency is lowered. In addition, when the method of flowing the molten steel back to the runner was performed, the molten refractory remaining in the runner was brought into another mold in a slow flow, and the refractory carried in was Since it is difficult to float in the mold, there is a risk that defects will be generated due to inclusions that are easily captured by the bottom of the steel ingot.
さて、上述した方法以外で鋳型間での湯面の高さを均一化する技術として、特許文献1〜3に示すものがある。
特許文献1は、1ランナー1モールドと1ランナー2モールド内側のモールド間の溶鋼面差をなくすることを目的としている。この特許文献1では、1つの注入管から定盤に形成された複数本のランナーを通して溶鋼を前記複数本のランナー上に夫々設けたモールド内に注入してなる下注ぎ造塊設備において、1ランナー2モールド側のランナーの断面積(d1)と1ランナー2モールドの側のランナーの断面積(d2)との比をd1:d2=1:0.40〜0.60としている。
As a technique for equalizing the height of the molten metal surface between molds other than the method described above, there are those shown in Patent Documents 1 to 3.
Patent document 1 aims at eliminating the molten steel surface difference between the molds inside 1 runner 1 mold and 1 runner 2 mold. In this Patent Document 1, in a down-pour ingot facility in which molten steel is injected into a mold provided on each of the plurality of runners through a plurality of runners formed on a surface plate from one injection tube, one runner The ratio of the cross-sectional area (d1) of the runner on the 2 mold side to the cross-sectional area (d2) of the runner on the 1 runner 2 mold side is d1: d2 = 1: 0.40 to 0.60.
特許文献2は、注入初期における注入管寄りのモールドに生じていた激しい湯暴れを防止し、且つ注入中期乃至末期におけるモールド内溶鋼の湯面差を減少することにより、鋼塊の表面疵および内部欠陥の発生とモールドの溶損を防止することを目的としている。この特許文献2では、少なくとも1本の1ランナー・多モールド注入管よりの湯上り口断面積を1ランナー・1モールドの湯上り口断面積の1.3〜2.5倍の大きさにしている。 Patent Document 2 discloses a method of preventing a hot water runoff that has occurred in a mold near an injection pipe in the initial stage of injection, and reducing the surface difference between the molten steel in the mold in the middle to the end of the injection, thereby reducing the surface flaws and the inside of the steel ingot. The purpose is to prevent the occurrence of defects and melt damage of the mold. In Patent Document 2, the cross-sectional area of the hot water inlet from at least one 1 runner / multi-mold injection pipe is 1.3 to 2.5 times the cross-sectional area of the hot water inlet of 1 runner / one mold.
特許文献3は、下注ぎ造塊作業の注入中期から後期におけるモールド間の溶鋼の湯上りを均一化するとともに、注入初期におけるモールド内での溶鋼の湯暴れを減少することにより、鋼塊底部欠陥や表面疵の防止、モールドの溶損を防止することを目的としている。この特許文献3では、1ランナー2モールド側の注入管よりのモールドの湯道管の湯上がり口を少なくとも1層の溶損性の内側耐火物と、耐溶損性の外側耐火物層とから構成している。これにより、モールド内の溶鋼の湯面があがるにつれて溶損が進み、その断面積が拡大され、この結果、注入中期、乃至後期におけるモールド内に進入する溶鋼の流れはスムーズとなり溶鋼の流入量は他のモールドより増加するため各モールド間の湯面差を減少している。 Patent Document 3 discloses that the molten steel rise between the molds in the middle to late injection of the bottom pouring ingot operation is made uniform, and that the molten steel runoff in the mold in the initial injection is reduced, thereby reducing the bottom defect of the steel ingot. It is intended to prevent surface flaws and mold melt damage. In this patent document 3, the runner outlet of the mold runner pipe from the 1 runner 2 mold side injection pipe is composed of at least one layer of a fusible inner refractory and a fusible outer refractory layer. ing. As a result, as the molten steel surface in the mold rises, the erosion progresses and the cross-sectional area increases, and as a result, the flow of molten steel entering the mold in the middle or later stage of injection becomes smooth and the inflow of molten steel is In order to increase from other molds, the difference in molten metal level between the molds is reduced.
また、上述した特許文献1〜3の他に、特許文献4に示す技術がある。この特許文献4は、溶融金属注入流に巻き込まれたガス体が湯道管を通じて鋳型内へ流れ込むことを防止することを目的としている。特許文献4では、下注ぎ管と鋳型との間に設けた湯道管の一部内径を他の湯道内径より小径にして、湯道全体の溶鋼流に抵抗を与え、ガスの巻き込みを防止している。 Moreover, there exists a technique shown in patent document 4 other than the patent documents 1-3 mentioned above. This patent document 4 aims to prevent a gas body caught in a molten metal injection flow from flowing into a mold through a runner pipe. In Patent Document 4, a partial inner diameter of a runner pipe provided between a bottom pouring pipe and a mold is made smaller than other runner inner diameters to provide resistance to the molten steel flow throughout the runner and prevent gas entrainment. doing.
特許文献1では、1ランナー1モールド側の湯道全長を細くしているため、鋳型の注入口から鋳型内に向けて噴出する溶鋼流速が速まり、スプラッシュを生じて鋳型内面に溶鋼が張り付き、インゴットの表面部に二重肌やの欠陥を生じる虞がある。また、特許文献1のように、湯道全長を細くしてしまうと、湯道内での溶鋼凝固やアルミナの付着によって詰まりが発生することがある。 In Patent Document 1, since the runner length on the mold side of 1 runner 1 mold is narrowed, the flow speed of the molten steel ejected from the mold inlet into the mold is increased, the splash is generated, and the molten steel sticks to the mold inner surface. There is a risk of causing double skin or defects on the surface of the ingot. In addition, as in Patent Document 1, if the runner is made thinner, the clogging may occur due to solidification of molten steel or adhesion of alumina in the runner.
特許文献2を、例えば、30トンを超える大型の鋳型に適用した場合、鋳造終了後に鋳型を取り外した後、インゴットを湯道から切り離す作業(根切りと呼ばれる)を行う際に、湯道を繋ぐ湯口が大きいために強度が大きく、切り離し作業が困難となる。
特許文献3では、耐火物の溶損を利用しているため、溶損した耐火物が鋳型内に進入し、介在物欠陥を生じたり、溶損速度が鋳造条件で異なり不安定になることがある。
When Patent Document 2 is applied to, for example, a large mold exceeding 30 tons, after removing the mold after the completion of casting, the runner is connected when performing an operation (referred to as root cutting) for separating the ingot from the runner. Since the gate is large, the strength is high and the separation work becomes difficult.
In Patent Document 3, since the refractory is melted, the melted refractory enters the mold to cause inclusion defects, and the melt speed may vary depending on the casting conditions and become unstable. is there.
特許文献4は、湯道径を細くすることが開示されているものの、湯道径を短くする基準が示されていないと共に、細くした湯道部の長さや鋳型の非対象についても示されておらず、湯面高さを一定にすることは困難である。
したがって、鋳型の配列が非対称である下注造塊装置を用いて造塊を行うに際して、特許文献1〜4を用いた場合でも、各鋳型間の湯面高さの差を少なくしつつ、高品質の鋼塊を製造することは困難であるのが実情である。
Although Patent Document 4 discloses that the runner diameter is narrowed, the standard for shortening the runner diameter is not shown, and the length of the narrow runner and the non-target of the mold are also shown. In addition, it is difficult to keep the hot water surface constant.
Therefore, when performing ingoting using a sub-casting ingot apparatus in which the arrangement of the molds is asymmetric, even when Patent Documents 1 to 4 are used, while reducing the difference in the molten metal surface height between the molds, The reality is that it is difficult to produce quality steel ingots.
本発明は、上述の問題に鑑みてなされたもので、各鋳型間の湯面高さの差を少なくしつつ、高品質の鋼塊を製造することができる下注造塊方法を提供することを目的とする。 The present invention has been made in view of the above-mentioned problems, and provides a sub-casting ingot method capable of producing a high-quality steel ingot while reducing the difference in molten metal surface height between the molds. With the goal.
本発明は、上記目的を達成するために、次の手段を講じた。
即ち、本発明に係る下注造塊方法は、注入管から分かれた湯道に、鋳型数が1基である第1鋳型と鋳型数が2基である第2鋳型とが設けられる下注造塊装置において下注ぎ鋳造を行うに際して、前記第1鋳型と第2鋳型とが全て同じ形状であり、前記第1鋳型の鋳型と第2鋳型の注入管側の鋳型が注入管に対し対称に配置されていて、前記第2鋳型の注入管側の鋳型と他の鋳型との距離が湯道の長さに対して無視できる程度の距離であり、前記第1鋳型側の湯道であって狭くなる細径部の内径D1(mm)が55〜90、前記第2鋳型側の湯道内径D2(mm)が70〜90、及び前記第1鋳型側の細径部以外の湯道内径D3(mm)が第2鋳型側の湯道内径D2と等しくされており、前記鋳型サイズが40t〜50tとされている場合に、前記注入管に注入する注湯流量は2〜10t/minとし、前記第1鋳型側の湯道長さと第2鋳型側の湯道長さとの比を1:2.3〜1:2.7の範囲に設定されており、前記第2鋳型側の湯道内径D2(mm)に対して、前記第1鋳型側の湯道であって狭くなる細径部の内径D1(mm)が式(1)〜式(3)を満たし、前記細径部の湯道長さL1(mm)が式(4)を満たし、前記細径部の終端位置と鋳型の注入口の距離L2(mm)とが式(5)を満たすことを特徴とする。
In order to achieve the above object, the present invention has taken the following measures.
That is, the lower Note ingot-making method according to the present invention, the runners were separated from the injection tube, the lower the number of molds that first mold and the number of mold 1 groups and the second mold is a 2 group provided Note When the down casting is performed in the ingot forming apparatus, the first mold and the second mold are all the same shape, and the mold of the first mold and the mold on the injection pipe side of the second mold are symmetrical with respect to the injection pipe. The distance between the mold on the injection pipe side of the second mold and the other mold is a distance that can be ignored with respect to the length of the runner, and the runner on the first mold side The narrow diameter portion has an inner diameter D1 (mm) of 55 to 90, the runner inner diameter D2 (mm) on the second mold side is 70 to 90, and a runner inner diameter D3 other than the narrow portion on the first mold side. (mm) are equal to the runner inner diameter D2 of the second mold side, when the mold size is a 40T~50t, The pouring flow rate to be injected into the injection tube is 2 to 10 t / min, and the ratio of the runner length on the first mold side to the runner length on the second mold side is in the range of 1: 2.3 to 1: 2.7. The inner diameter D1 (mm) of the narrow diameter portion which is a runner on the first mold side and becomes narrower than the runner inner diameter D2 (mm) on the second mold side is expressed by the formula (1). ~ Equation (3) is satisfied, the runner length L1 (mm) of the narrow portion satisfies Formula (4), and the distance L2 (mm) between the terminal position of the narrow portion and the casting inlet of the mold is expressed by the formula ( 5) is satisfied.
本発明によれば、各鋳型間の湯面高さの差を少なくしつつ、高品質の鋼塊を製造することができる。 According to the present invention, it is possible to manufacture a high-quality steel ingot while reducing the difference in the molten metal surface height between the molds.
以下、図を参照しながら、本発明の実施形態について説明する。
造塊法として、下注ぎ造塊法と上注ぎ造塊法の2種類がある。上注ぎ造塊法では鋳型の上部の開口部に取鍋から直接、溶鋼を注ぎ込んで鋳造するのに対し、下注ぎ造塊法では、注入管と呼ばれるロート状の注ぎ口が設けられた垂直の管に溶鋼を注ぎ込んで、湯道を介して鋳型に注湯することにより鋳造を行う。本発明では、造塊法のうち、下注ぎ造塊法を対象としている。
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
There are two types of ingot forming methods: a bottom pouring ingot method and an upper pouring ingot method. In the top pouring ingot method, molten steel is poured directly from the ladle into the opening at the top of the mold and cast, whereas in the bottom pouring ingot method, a vertical pouring with a funnel-shaped spout called an injection tube is provided. Casting is performed by pouring molten steel into a pipe and pouring it into a mold through a runner. The present invention is directed to the bottom pouring ingot method among the ingot making methods.
下注ぎ造塊法において、2個以上の鋳型に同時に注湯する場合は、注入管の下部から左右若しくは多方向に分岐された湯道を経由して、各鋳型の底の注入口から当該鋳型内に溶鋼が注湯される。ここで、鉄鋼メーカでは多くの場合、大量のインゴットを効率良く鋳造し、注入場から搬出するため、鋳造したインゴットを鋳型と注入管、湯道ともども、運搬用列車の台車に積載して移動させる。このようなことから、湯道は、台車の長手方向、即ち、左右方向に沿った配列になる。つまり、湯道は、注入管から左右に分かれて設置される。 In case of pouring simultaneously into two or more molds in the bottom pouring ingot method, the molds are injected from the injection port at the bottom of each mold via a runner that branches from the lower part of the injection pipe to the left or right or in multiple directions. Molten steel is poured inside. Here, in many cases, steel makers efficiently cast a large amount of ingots and carry them out of the pouring station, so that the cast ingots, molds, pouring pipes, and runners are also loaded and moved on the carriage train carriage. . For this reason, the runners are arranged along the longitudinal direction of the carriage, that is, the left-right direction. That is, the runner is installed separately from the injection tube on the left and right.
さて、上述したように、下注ぎ造塊法では、通常、注入管を基準として、左右対称に鋳型を配置する。ここで、取鍋の溶鋼重量と、鋳造する1つの鋼塊重量と兼ね合いによっては、鋳型数(鋳型の個数)が奇数にならざるを得ない場合が生じる。例えば、取鍋の溶鋼量が250トンで、鋳型内の鋼塊重量が50トンの場合、注入管を基準として、一方側に設置された3基の鋳型と、他方側に設置された2基の鋳型とで同時に鋳造することになる。 Now, as described above, in the bottom pouring ingot method, the molds are usually arranged symmetrically with respect to the injection tube. Here, depending on the balance between the molten steel weight of the ladle and the weight of one ingot to be cast, the number of molds (number of molds) may have to be an odd number. For example, when the amount of molten steel in the ladle is 250 tons and the weight of the steel ingot in the mold is 50 tons, three molds installed on one side and two units installed on the other side based on the injection pipe The same mold is cast at the same time.
このように、本発明の下注造塊方法では、溶鋼を注入する注入管の下端側から湯道を分岐させたうえで、注入管を基準として、鋳型が非対称に設置して鋳造を行うことを前提としている。
まず、下注造塊方法を行う下注造塊装置の構造について説明する。
図1は、下注造塊装置の全体を示している。
As described above, in the ingot casting method of the present invention, the runner is branched from the lower end side of the injection pipe for injecting molten steel, and then the casting is performed with the casting mold being asymmetrically set based on the injection pipe. Is assumed.
First, the structure of the lower casting ingot apparatus which performs the lower casting ingot method is demonstrated.
FIG. 1 shows the entire lower casting ingot apparatus.
図1に示すように、下注造塊装置1は、下注ぎ造塊法により溶鋼2を鋳造するものであ
って、取鍋3内の溶鋼2を注入する注入管4と、注入管4の下端から左右に分岐した湯道5と、この湯道5に連通する鋳型6とを備えている。
詳しくは、定盤7には1本の注入管4が立設され、注入管4の下端であって定盤7の内部には当該注入管4から枝分かれした湯道5が形成されている。また、注入管4を基準として、右側に1基の鋳型(第1鋳型という)6aが設けられ、左側に2基の鋳型(第2鋳型という)6bが設けられている。なお、下注造塊装置1は、注入管4を基準として、鋳型6が非対象に設けられたものであればよく、鋳型6(6a、6b)の位置や鋳型6(6a、6b)の数(鋳型数)は、上述した例に限定されない。また、注入管4、湯道5、鋳型6、注入口8の内面は耐火物で構成されている。
As shown in FIG. 1, the lower casting ingot device 1 is for casting molten steel 2 by the lower pouring ingot method, and includes an injection pipe 4 for injecting molten steel 2 in a ladle 3, and an injection pipe 4. A runway 5 branched from the lower end to the left and right and a mold 6 communicating with the runway 5 are provided.
Specifically, one injection pipe 4 is erected on the platen 7, and a runner 5 branched from the injection pipe 4 is formed inside the platen 7 at the lower end of the injection pipe 4. With reference to the injection tube 4, one template (referred to as a first template) 6a is provided on the right side, and two templates (referred to as second templates) 6b are provided on the left side. In addition, the lower casting ingot making apparatus 1 should just be the thing in which the casting_mold | template 6 was provided in non-object with the injection | pouring pipe | tube 4, and the position of casting_mold | template 6 (6a, 6b) and the casting_mold | template 6 (6a, 6b) The number (number of molds) is not limited to the example described above. The inner surfaces of the injection pipe 4, the runner 5, the mold 6 and the injection port 8 are made of a refractory material.
注入管4の下端から第1鋳型6a側に向かう湯道5aは、第1鋳型6aの下部において幅方向中央部に形成された注入口8に接続されている。注入管4の下端から第2鋳型6b側に向かう湯道5bは、第2鋳型6bの下部において、幅方向中央部に形成された注入口8に接続されている。また、湯道5aには、湯道5bよりも内径が小さい細径部9が形成されている。 The runner 5a from the lower end of the injection pipe 4 toward the first mold 6a is connected to an injection port 8 formed at the center in the width direction at the lower part of the first mold 6a. The runner 5b from the lower end of the injection pipe 4 toward the second mold 6b is connected to an injection port 8 formed at the center in the width direction at the lower part of the second mold 6b. The runner 5a is formed with a narrow portion 9 having an inner diameter smaller than that of the runner 5b.
第1鋳型6a側の湯道の全長A1と、第2鋳型6b側の湯道の全長A2との比(A2/A1)は、1:2.3〜1:2.7の範囲に設定されている。
図2は、鋳型、注入管の間隔を0として示した場合の下注造塊装置1の平面図を示したものである。図2を用いて、A2/A1について説明する。
図2に示すように、第1鋳型6a側の湯道の全長A1は、注入管4の外寸法dの1/2(1/2d)と、1基の第1鋳型6a側の外寸法Dの1/2(1/2D)の合計(1/2d+1/2D)になる。一方、第2鋳型6b側の湯道の全長A2は、注入管4の外寸法dの1/2(1/2d)と、2基の第2鋳型6a側の外寸法Dの3/2(3/2D)との合計(1/2d+3/2D)になる。
The ratio (A2 / A1) between the full length A1 of the runner on the first mold 6a side and the full length A2 of the runway on the second mold 6b side is set in a range of 1: 2.3 to 1: 2.7. ing.
FIG. 2 is a plan view of the lower casting ingot device 1 when the distance between the casting mold and the injection tube is set to zero. A2 / A1 will be described with reference to FIG.
As shown in FIG. 2, the total length A1 of the runner on the first mold 6a side is 1/2 (1 / 2d) of the outer dimension d of the injection tube 4 and the outer dimension D on the one first mold 6a side. (1 / 2d + 1 / 2D). On the other hand, the full length A2 of the runner on the second mold 6b side is 1/2 (1 / 2d) of the outer dimension d of the injection tube 4 and 3/2 (2/2 of the outer dimension D on the two second molds 6a side. 3 / 2D) and (1 / 2d + 3 / 2D).
ここで、第1鋳型6a側の湯道の全長A1と、第2鋳型6b側の湯道の全長A2との比(A2/A1)を、注入管4の外寸法d及び鋳型の外寸法Dとで表すと、A2/A1=(1/2d+3/2D)/(1/2d+1/2D)={(1/2d+1/2D)+D}/(1/2d+1/2D)=1+2D/(d+D)となる。ここで、通常、d=0.2D〜0.5Dであるため、A2/A1≒2.3〜2.7となる。実際の鋳型6、注入管4の配列では、鋳型間や注入管と鋳型間はスペースが設けられるが、このスペースの大きさは、鋳型6や注入管4の大きさに比べると小さいので、このA2/A1の値に影響は与えない。 Here, the ratio (A2 / A1) between the full length A1 of the runner on the first mold 6a side and the full length A2 of the runner on the second mold 6b side is defined as the outer dimension d of the injection tube 4 and the outer dimension D of the mold. In this case, A2 / A1 = (1 / 2d + 3 / 2D) / (1 / 2d + 1 / 2D) = {(1 / 2d + 1 / 2D) + D} / (1 / 2d + 1 / 2D) = 1 + 2D / (d + D) Become. Here, since d = 0.2D to 0.5D normally, A2 / A1≈2.3 to 2.7. In the actual arrangement of the mold 6 and the injection tube 4, a space is provided between the molds and between the injection tube and the mold, but the size of this space is smaller than the size of the mold 6 and the injection tube 4. It does not affect the value of A2 / A1.
以上、まとめると、当該下注造塊装置1は、第1鋳型6aの鋳型数と第2鋳型6bの鋳型数とが異なる装置であって、第1鋳型6a側の湯道長さL1と、第2鋳型6b側の湯道長さL2との比(A2/A1)が1:2.3〜1:2.7の範囲に設定された装置である。
次に、下注造塊方法について詳しく説明する。
In summary, the lower ingot casting apparatus 1 is an apparatus in which the number of molds of the first mold 6a and the number of molds of the second mold 6b are different, and the runner length L1 on the first mold 6a side, 2 The ratio (A2 / A1) to the runner length L2 on the mold 6b side is set in the range of 1: 2.3 to 1: 2.7.
Next, the ingot casting method will be described in detail.
例えば、左側に2基の鋳型を設置し、右側に2基の鋳型を設置した左右対称の鋳造において、鋳型間の注入速度は略一定と考えられるが、水モデル実験結果により、当該左右対称の鋳造でも、鋳型毎の注入流量のバラツキが生じている。しかしながら、左右対称の鋳造において、注湯流量を変化させて鋳造し、鋳型毎の注入流量のバラツキがあったとしても、品質上の問題は発生していない。そこで、左右非対称の鋳造においても、最大注入流量差(注入流量の差が最も大きい場合での流量差)が従来のような左右対称の鋳造と同等以下であれば問題がないとした。 For example, in a symmetric casting in which two molds are installed on the left side and two molds are installed on the right side, the injection speed between the molds is considered to be substantially constant. Even in casting, there is a variation in the injection flow rate for each mold. However, in symmetric casting, there is no problem in quality even if casting is performed by changing the pouring flow rate and there is variation in the injection flow rate for each mold. Therefore, even in the asymmetrical casting, there is no problem if the maximum injection flow rate difference (flow rate difference when the injection flow rate difference is the largest) is equal to or less than that of the conventional symmetrical casting.
図3及び図4は、左側に2基、右側に2基の左右対称の鋳型における水モデルの結果をまとめたものである。
水モデルでは、注湯流量を10L/min、20L/min、30L/minの3つのパターンとし、各パターンにおいて、左右の湯道の内径を同じとした。湯道の内径は、14mmφ、16mmφ、18mmφとした。また、水モデルでは、注湯流量を各パターンに応じて変化させ、各鋳型への湯上り速度を測定し、各鋳型への注入流量を求めた。左右に配置した鋳型の合計は4基であるため、各鋳型への注入流量は、注湯流量を鋳型基数の4で割った値(2.5L/min、5.0L/min、7.5L/min)である。
FIG. 3 and FIG. 4 summarize the results of the water model with two symmetrical molds on the left and two on the right.
In the water model, the pouring flow rate was set to three patterns of 10 L / min, 20 L / min, and 30 L / min, and the inner diameters of the left and right runners were the same in each pattern. The inner diameter of the runner was 14 mmφ, 16 mmφ, and 18 mmφ. In the water model, the pouring flow rate was changed according to each pattern, the hot water rising speed to each mold was measured, and the pouring flow rate to each mold was obtained. Since the total number of molds arranged on the left and right is 4, the injection flow rate into each mold is a value obtained by dividing the pouring flow rate by 4 of the number of mold groups (2.5 L / min, 5.0 L / min, 7.5 L). / Min).
このような水モデルでは、湯道管径(湯道内径)と、各注入流量における最大注入流量差との関係は、図3に示す結果となった。また、最大注入流量差を各鋳型への注入流量で割り、最大注入流量差をパーセントで示すと図4の結果となった。
図4に示すように、湯道の内径が変化したとしても、注入流量において最大注入流量差が7.1%以下であれば、品質上の問題は生じないと考えられる。
In such a water model, the relationship between the runner pipe diameter (runner bore inner diameter) and the maximum injection flow rate difference at each injection flow rate is the result shown in FIG. Further, when the maximum injection flow rate difference is divided by the injection flow rate into each mold and the maximum injection flow rate difference is shown in percentage, the result shown in FIG. 4 is obtained.
As shown in FIG. 4, even if the inner diameter of the runner changes, if the maximum injection flow rate difference is 7.1% or less in the injection flow rate, it is considered that there will be no quality problem.
次に、左右非対称の鋳造において、鋳型間の注入速度を一定にするための湯道内径(湯道管径)の検証を行った。
まず、図1に示した下注造塊装置1の1/5に相当する非対称の水モデルの模型を作成する。具体的には、図5に示すように、第1鋳型6aに相当する1基の鋳型(鋳型Cという)を右側に配置し、第2鋳型6bに相当する2基の鋳型(鋳型A、鋳型Bという)を左側に配置した模型を作成する。また、第1鋳型6a側の湯道5aに相当する湯道10aを鋳型Cに接続すると共に、第2鋳型6b側の湯道5bに相当する湯道10bを鋳型A及び鋳型Bに接続する。
Next, in the asymmetric casting, the runner inner diameter (runner pipe diameter) was verified in order to make the injection speed between the molds constant.
First, a model of an asymmetric water model corresponding to 1/5 of the lower casting ingot device 1 shown in FIG. 1 is created. Specifically, as shown in FIG. 5, one template corresponding to the first template 6a (referred to as template C) is arranged on the right side, and two templates corresponding to the second template 6b (template A, template C). B) is placed on the left side. Further, the runner 10a corresponding to the runner 5a on the first mold 6a side is connected to the mold C, and the runner 10b corresponding to the runner 5b on the second mold 6b side is connected to the mold A and the mold B.
この水モデルでは、湯道10aの内径(第1鋳型6a側の湯道5aに相当する内径)をD1とし、湯道10bの内径(第2鋳型6b側の湯道5bに相当する内径)をD2する。説明の便宜上、湯道10aの内径D1を「第1湯道内径D1」といい、湯道10bの内径を「第2湯道内径D2」という。
水モデルを用いて、第1湯道内径D1と、第2湯道内径D2と、注湯流量とを、それぞれ変化させた場合の各鋳型への注入流量を求めた。なお、第2湯道内径D2は、14mmφ、16mmφ、18mmφとした。
In this water model, the inner diameter of the runner 10a (the inner diameter corresponding to the runner 5a on the first mold 6a side) is D1, and the inner diameter of the runner 10b (the inner diameter corresponding to the runner 5b on the second mold 6b side). D2. For convenience of explanation, the inner diameter D1 of the runner 10a is referred to as "first runner inner diameter D1", and the inner diameter of the runner 10b is referred to as "second runner inner diameter D2."
Using the water model, the injection flow rate into each mold when the first runner inner diameter D1, the second runner inner diameter D2, and the pouring flow rate were changed was obtained. The second runner inner diameter D2 was 14 mmφ, 16 mmφ, and 18 mmφ.
図6は、第2湯道内径D2を16mmφとした場合において、第1湯道内径D1と、鋳型への注入流量との関係をまとめたものである。水モデルの実験結果から各鋳型(鋳型A、鋳型B、鋳型C)への注入流量と、注湯流量と、第1湯道内径D1との関係を整理すると、各鋳型への注入流量は、式(I)〜式(III)に示す結果となった。 FIG. 6 summarizes the relationship between the first runner inner diameter D1 and the injection flow rate into the mold when the second runner inner diameter D2 is 16 mmφ. If the relationship between the injection flow rate into the molds (mold A, mold B, mold C), the pouring flow rate, and the first runner inner diameter D1 is arranged from the experimental results of the water model, the injection flow rate into each mold is The results shown in Formula (I) to Formula (III) were obtained.
次に、左右非対称の鋳型の注入流量においても、左右対称の鋳型における最大注入流量差が範囲以下(7.1%以下)となるための湯道内径、即ち、最適な湯面上昇速度を求める。詳しくは、式(I)〜式(III)に示された第1湯道内径D1と、最大注入流量差との関係を整理した。図7は、注湯流量Qを変化させた場合であって第2湯道内径D2が16mmφである場合における第1湯道内径D1と、鋳型への最大注入流量差との関係をまとめたものである。図7に示すように、注湯流量Qの増加とともに最大注入流量差は増加するが各注湯流量において、極小点が存在する。 Next, also in the injection flow rate of the asymmetric mold, the runner inner diameter for obtaining the maximum injection flow difference in the symmetrical mold is less than the range (7.1% or less), that is, the optimum melt surface rising speed is obtained. . Specifically, the relationship between the first runner inner diameter D1 shown in the formulas (I) to (III) and the maximum injection flow rate difference was arranged. FIG. 7 summarizes the relationship between the first runner inner diameter D1 when the pouring flow rate Q is changed and the second runner inner diameter D2 is 16 mmφ and the maximum injection flow rate difference into the mold. It is. As shown in FIG. 7, the maximum injection flow rate difference increases as the pouring flow rate Q increases, but there is a minimum point at each pouring flow rate.
そして、図7に示した最大注入流量差を図4と同じようにパーセントに置き換え、そのうえで、最大注入流量差が7.1%以下となる第1湯道内径D1の最小径と最大径を求める。図8は、図7に基づいて、注湯流量と、最大注入流量差が7.1%以下となる第1湯道内径D1の最小径と最大径をまとめたものである。図8に示すように、所定の注湯流量Qにおいて、第1湯道内径D1が最小径と最大径との範囲内にあるときは、最大注入流量差が7.1%以下となる。 Then, the maximum injection flow rate difference shown in FIG. 7 is replaced with a percentage as in FIG. 4, and then the minimum diameter and the maximum diameter of the first runner inner diameter D1 at which the maximum injection flow rate difference is 7.1% or less are obtained. . FIG. 8 summarizes the minimum and maximum diameters of the first runner inner diameter D1 where the difference between the pouring flow rate and the maximum injection flow rate is 7.1% or less, based on FIG. As shown in FIG. 8, at a predetermined pouring flow rate Q, when the first runner inner diameter D1 is within the range between the minimum diameter and the maximum diameter, the maximum injection flow rate difference is 7.1% or less.
上述した実施形態では、第2湯道内径D2が16mmφであるときの第1湯道内径D1の最小径と最大径とを求めているが、第2湯道内径D2が14mmφ、18mmφである
ときの第1湯道内径D1の最小径と最大径とについても同様の方法で求め、第1湯道内径D1と、第2湯道内径D2と、注湯流量との関係を整理すると、式(1a)〜式(3a)に示す結果となった。
In the embodiment described above, the minimum and maximum diameters of the first runner inner diameter D1 when the second runner inner diameter D2 is 16 mmφ are obtained, but when the second runner inner diameter D2 is 14 mmφ and 18 mmφ. The minimum diameter and the maximum diameter of the first runner inner diameter D1 are obtained by the same method, and the relationship between the first runner inner diameter D1, the second runner inner diameter D2, and the pouring flow rate is expressed by the formula ( The results shown in 1a) to (3a) were obtained.
次に、式(A)を用いて、水モデルにおける注湯流量Qを実機のスループットWR(t/min)に換算すると、スループット(実機の注湯流量)WRと、第1湯道内径D1(第1鋳型6a側の湯道内径D1に相当)と、第2湯道内径D2(第2鋳型6b側の湯道内径D2に相当)とは、式(1)〜式(3)となった。 Next, using equation (A), it is converted pouring flow rate Q in the water model to a real machine throughput W R (t / min), throughput (actual pouring rate) W R and, first runner inner diameter D1 (corresponding to the runner inner diameter D1 on the first mold 6a side) and second runner inner diameter D2 (corresponding to the runner inner diameter D2 on the second mold 6b side) are expressed by the following equations (1) to (3). became.
式(1)〜式(3)に示すように、第1鋳型6a側の湯道内径D1を、第2鋳型6b側の湯道内径D2に基づいて設定することにより、第1鋳型6a側の湯上がり速度と、第2鋳型6b側の湯上がり速度とを一定にすることができると考えられる。つまり、第1鋳型6a側の湯道内径D1を、式(1)〜式(3)に基づいて、第2鋳型6b側の湯道内径D2よりも細くすることにより、湯上がり速度を一定にすることができると考えられる。 As shown in the equations (1) to (3), by setting the runner inner diameter D1 on the first mold 6a side based on the runner inner diameter D2 on the second mold 6b side, It is considered that the hot water rising speed and the hot water rising speed on the second mold 6b side can be made constant. That is, by making the runner inner diameter D1 on the first mold 6a side smaller than the runner inner diameter D2 on the second mold 6b side based on the expressions (1) to (3), the hot water rising speed is made constant. It is considered possible.
発明者は、第1鋳型6a側の湯道5aと、第2鋳型6b側の湯道5bとの関係について、さらに検証したところ、第1鋳型6a側の湯道内径D1、即ち、湯道5aの内径を細くしたとしても、細くした湯道5aが短すぎると効果が無いことが分かった。
そこで、湯道5aの長さを求めるため、まず、水モデルにおいて、図5に示すように、実機の湯道5aに相当する湯道10aに細径部11(実機の細径部9に相当)を形成して、最大注入流量差が7.1%以下となる細径部11の長さL1(実機の湯道5aに形成した細径部9の長さに相当)について求めた。説明の便宜上、細径部11の長さL1は、「細径部長さL1」という。
The inventor further examined the relationship between the runner 5a on the first mold 6a side and the runner 5b on the second mold 6b side. As a result, the runner inner diameter D1 on the first mold 6a side, that is, the runner 5a. It has been found that even if the inner diameter of the pipe is reduced, there is no effect if the reduced runner 5a is too short.
Therefore, in order to obtain the length of the runner 5a, first, in the water model, as shown in FIG. 5, the small diameter portion 11 (corresponding to the small diameter portion 9 of the actual machine) is connected to the runway 10a corresponding to the actual runner 5a. ) And the length L1 of the small diameter portion 11 (corresponding to the length of the small diameter portion 9 formed in the actual runner 5a) at which the maximum injection flow rate difference is 7.1% or less was obtained. For convenience of explanation, the length L1 of the small diameter portion 11 is referred to as “thin diameter portion length L1”.
なお、この水モデル実験では、細径部11の内径は、上述した第1湯道内径D1に相当することとし、この細径部11の内径D1(第1湯道内径D1)と、第2湯道内径D2とは、式(1a)〜式(3a)を満たしていることを条件とした。
第2湯道内径D2を16mmφとし、第1湯道内径D1を11mmφとした場合における最大注入流量差と、細径部長さL1との関係は、図9に示す結果となった。図9に示す矢印は、最大注入流量差が7.1%となったときの細径部長さL1を示しており、この細径部長さL1の長さ以上で最大注入流量差が7.1%以下となることを示す。図9に示すように、最大注入流量差が7.1%ときの細径部長さL1は、注湯流量が増加するに伴って大きくなる。
In this water model experiment, the inner diameter of the narrow diameter portion 11 corresponds to the above-described first runner inner diameter D1, and the inner diameter D1 (first runner inner diameter D1) of the narrow diameter portion 11 and the second runner diameter D1. The runner inner diameter D2 was on condition that the formulas (1a) to (3a) were satisfied.
The relationship between the maximum injection flow rate difference and the small diameter portion length L1 when the second runner inner diameter D2 is 16 mmφ and the first runner inner diameter D1 is 11 mmφ is the result shown in FIG. The arrow shown in FIG. 9 indicates the length L1 of the small diameter portion when the maximum injection flow rate difference is 7.1%, and the maximum injection flow rate difference is 7.1 or more beyond the length of the small diameter portion length L1. % Or less. As shown in FIG. 9, the small diameter portion length L1 when the maximum injection flow rate difference is 7.1% increases as the pouring flow rate increases.
以上のように、第2湯道内径D2を16mmφした場合において、最大注入流量差が7.1%ときの細径部長さL1と、細径部11の内径D1(第1湯道内径D1)と注湯流量Qとの関係を水モデルにより求めると、図10に示す結果となった。図10に示すように、細径部11の内径D1がいずれの場合であっても、注湯流量の増加に伴って、細径部長さL1は略直線的に増加している。 As described above, when the second runner inner diameter D2 is 16 mmφ, the narrow diameter portion length L1 when the maximum injection flow rate difference is 7.1% and the inner diameter D1 of the narrow diameter section 11 (first runner inner diameter D1). When the relationship between the hot water flow rate Q and the pouring flow rate Q was obtained from the water model, the result shown in FIG. 10 was obtained. As shown in FIG. 10, regardless of the inner diameter D1 of the small-diameter portion 11, the small-diameter portion length L1 increases substantially linearly as the pouring flow rate increases.
図9に基づいて、細径部長さL1と、細径部11の内径D1と、注湯流量との関係を、実験式で整理すると、式(4a)に示す通りとなった。 Based on FIG. 9, the relationship between the small-diameter portion length L1, the inner diameter D1 of the small-diameter portion 11 and the pouring flow rate is arranged as shown in Equation (4a).
次に、式(A)を用いて、水モデルにおける注湯流量Qを実機のスループットWRに換算すると、スループット(実機の注湯流量)WRと、細径部11の内径D1等との関係は
、式(4)となった。
Next, using equation (A), is converted pouring flow rate Q in the water model to a real machine throughput W R, throughput (actual pouring flow rate) and W R, the inner diameter D1 or the like of the small-diameter portion 11 The relationship is represented by equation (4).
以上のように、第1鋳型6a側の湯道5aであって狭くなる細径部の内径D1及び細径部長さL1が式(4)を満たすように設定することにより、第1鋳型6a及び第2鋳型6b側の湯上がり速度を一定にすることができる。
つまり、第2鋳型6b側の湯道内径D2(第2湯道内径D2)に対して、第1鋳型6a側の湯道5aであって狭くなる細径部9の内径D1(細径部11の内径D1)が式(1)〜式(3)を満たし、細径部9の湯道長さL1(細径部長さL1)が式(4)を満たすことによって、第1鋳型6a及び第2鋳型6b側の湯上がり速度を一定にすることができる。
As described above, the first mold 6a and the runner 5a on the first mold 6a side are set so that the inner diameter D1 and the narrow section length L1 of the narrow section narrowed satisfy the formula (4). The hot water rising speed on the second mold 6b side can be made constant.
That is, with respect to the runner inner diameter D2 (second runner inner diameter D2) on the second mold 6b side, the inner diameter D1 (thinner diameter section 11) of the narrow diameter portion 9 which is the runner 5a on the first mold 6a side and becomes narrower. The inner diameter D1) of the first mold 6a and the second mold 6a by satisfying the formulas (1) to (3) and the runner length L1 (the narrow diameter portion length L1) of the narrow diameter portion 9 satisfying the formula (4). The hot water rising speed on the mold 6b side can be made constant.
さて、上述した条件を満たした場合であっても、湯道5aの細径部9の終端位置(細径部9の出口)から第1鋳型6aの注入口8までの距離L2が短いと、図11に示すようなスプラッシュが発生することがある。スプラッシュが生じると、特公開昭54−62120号公報に述べられているように、「溶鋼飛沫のモールド内壁付着によるへげ疵の如き鋼塊の表面疵あるいは内部欠陥等が発生する」ことが知られているのでスプラッシュの発生を抑える必要がある。 Even if the above-described conditions are satisfied, if the distance L2 from the end position of the narrow diameter portion 9 of the runner 5a (the outlet of the small diameter portion 9) to the injection port 8 of the first mold 6a is short, Splash as shown in FIG. 11 may occur. When splash occurs, as described in Japanese Patent Publication No. 54-62120, it is known that “a surface flaw or internal defect of a steel ingot such as a hail caused by adhesion of molten steel droplets to the inner wall of a mold” occurs. Therefore, it is necessary to suppress the occurrence of splash.
そこで、水モデルにおいて、図5に示すように、湯道10aの細径部11の終端部12aから鋳型Cの注入口13までの部分には、細径部11よりも大きな内径を有する大径部14を設けた。なお、大径部14の内径D3(第1鋳型6a側の湯道5aにおいて、細径部9以外の部分の内径に相当)は、鋳型A及び鋳型Bの湯道10b(第2鋳型6b側の湯道に相当)と同じ内径とした。これは、湯道を構成する耐火物の管理上、耐火物の種類を増やさないためである。以下、説明の便宜上、大径部14の内径D3は、「細径部外内径」という。 Therefore, in the water model, as shown in FIG. 5, the portion from the end portion 12 a of the narrow diameter portion 11 of the runner 10 a to the inlet 13 of the mold C has a large diameter having a larger inner diameter than the small diameter portion 11. Part 14 was provided. The inner diameter D3 of the large diameter portion 14 (corresponding to the inner diameter of the portion other than the narrow diameter portion 9 in the runner 5a on the first mold 6a side) is the runner 10b of the mold A and the mold B (on the second mold 6b side). The inner diameter is the same as that of This is because the number of types of refractories is not increased in the management of refractories constituting the runner. Hereinafter, for convenience of explanation, the inner diameter D3 of the large-diameter portion 14 is referred to as a “small-diameter outer diameter”.
この水モデルでは、細径部11の内径D1(第1湯道内径D1)、第2湯道内径D2、細径部長さL1等は、上述した式(1a)〜式(4a)を満たすことを前提とした。
この水モデルでは、湯道10aの細径部11の終端部12aから鋳型Cの注入口13(第1鋳型6aの注入口8に相当)までの距離L2(離間距離L2という)を変化させ、スプラッシュの有無について調査を行った。スプラッシュの状況は、鋳造開始時の注入流の噴出状況をビデオ撮影によって撮像して確認した。
In this water model, the inner diameter D1 (first runner inner diameter D1), the second runner inner diameter D2, the narrow diameter section length L1, and the like of the narrow diameter portion 11 satisfy the above-described formulas (1a) to (4a). Assumed.
In this water model, the distance L2 (referred to as the separation distance L2) from the terminal end 12a of the narrow diameter portion 11 of the runner 10a to the inlet 13 of the mold C (corresponding to the inlet 8 of the first mold 6a) is changed, The presence or absence of splash was investigated. The state of the splash was confirmed by imaging the injection state of the injection flow at the start of casting.
第2湯道内径D2が18mmφ、第1湯道内径D1が13mm、細径部外内径D3が18mm、細径部長さL1が285mmであるときの注湯流量と、離間距離L2と、スプラッシュの有無の関係は図12に示す結果となった。図12に示すように、注湯流量の増加に応じて離間距離L2を大きくすれば、スプラッシュは発生しなくなる。
また、第2湯道内径D2が16mmφ、第1湯道内径D1が11mm、細径部外内径D3が16mm、細径部長さL1が285mmであるときの注湯流量と、離間距離L2と、スプラッシュの有無の関係は図13に示す結果となった。第2湯道内径D2が18mmφ、第1湯道内径D1が11mm、細径部外内径D3が18mm、細径部長さL1が285mmであるときの注湯流量と、離間距離L2と、スプラッシュの有無の関係は図14に示す結果となった。
The pouring flow rate when the second runner inner diameter D2 is 18 mmφ, the first runner inner diameter D1 is 13 mm, the narrow outer diameter D3 is 18 mm, and the narrow diameter L1 is 285 mm, the separation distance L2, and the splash The presence / absence relationship was as shown in FIG. As shown in FIG. 12, if the separation distance L2 is increased as the pouring flow rate increases, the splash does not occur.
In addition, the pouring flow rate when the second runner inner diameter D2 is 16 mmφ, the first runner inner diameter D1 is 11 mm, the small diameter outer diameter D3 is 16 mm, and the small diameter length L1 is 285 mm, and the separation distance L2. The relationship of the presence or absence of splash was as shown in FIG. The pouring flow rate when the second runner inner diameter D2 is 18 mmφ, the first runner inner diameter D1 is 11 mm, the outer diameter inner diameter D3 is 18 mm, and the smaller diameter section length L1 is 285 mm, the separation distance L2, and the splash The presence / absence relationship was as shown in FIG.
図12〜14に基づいて、スプラッシュが発生しない離間距離L2と、細径部外内径D3と、注湯流量との関係を整理すると図15に示すものとなり、実験式で示すと式(5a)に示す通りとなった。 Based on FIGS. 12 to 14, the relationship among the separation distance L <b> 2 at which no splash occurs, the outer diameter D <b> 3 of the small-diameter portion, and the pouring flow rate is arranged as shown in FIG. 15. It became as shown in.
次に、式(A)を用いて、水モデルにおける注湯流量を実機のスループットWRに換算すると、スループット(実機の注湯流量)WRと、細径部外内径D3等との関係は、式(5)となった。 Next, using equation (A), is converted pouring flow rate in water model of a real machine throughput W R, throughput and (actual pouring rate) W R, the relationship between the small diameter outer inner diameter D3, etc. The equation (5) was obtained.
以上、本発明によれば、注入管から分かれた湯道に、第1鋳型と第2鋳型とが設けられ且つ第1鋳型の鋳型数と第2鋳型の鋳型数とが異なる下注造塊装置において下注ぎ鋳造を行うに際して、注入管に注入する注湯流量は2〜10t/minとし、第1鋳型側の湯道長さと第2鋳型側の湯道長さとの比を1:2.3〜1:2.7の範囲に設定されており、第2鋳型側の湯道内径D2(mm)に対して、第1鋳型側の湯道であって狭くなる細径部の内径D1(mm)が式(1)〜式(3)を満たし、細径部の湯道長さL1(mm)が式(4)を満たし、細径部の終端位置と鋳型の注入口の距離L2(mm)とが式(5)を満たすように鋳造を行う。 As described above, according to the present invention, the first casting mold and the second casting mold are provided in the runner separated from the injection pipe, and the number of casting molds of the first casting mold and the number of casting molds of the second casting mold are different. In the case of downcasting, the flow rate of pouring poured into the pouring tube is 2 to 10 t / min, and the ratio of the runner length on the first mold side to the runner length on the second mold side is 1: 2.3 to 1 Is set to a range of 2.7, and the inner diameter D1 (mm) of the narrow diameter portion of the runner on the first mold side is narrower than the runner inner diameter D2 (mm) on the second mold side. Expression (1) to Expression (3) are satisfied, the runner length L1 (mm) of the small diameter portion satisfies Expression (4), and the distance L2 (mm) between the end position of the small diameter portion and the casting inlet of the mold is Casting is performed so as to satisfy Expression (5).
なお、水モデル流量を実機のスループットに換算するに際しては、フルード数を適用した。即ち、流体の流速を「V」、代表寸法を「L」、動粘性係数を「ν」、フルード数を「Fr」、レイノルズ数を「Re」、重力の加速度を「g」とするとこれらの関係は、式(B)、(C)となる。 The fluid number was applied when converting the water model flow rate into the actual machine throughput. That is, when the fluid flow velocity is “V”, the representative dimension is “L”, the kinematic viscosity coefficient is “ν”, the Froude number is “Fr”, the Reynolds number is “Re”, and the acceleration of gravity is “g”. The relationship is expressed by equations (B) and (C).
運動方程式を無次元化すると、(慣性項)+(粘性項)/Re+(外力項)=0でFrは外力項に(1/Fr2)で入る。Reが大きくなれば、(粘性項)/Reが小さくなるため、Reは運動方程式より消去されることになる。Re>4000以上で通常乱流領域とされており、Fr数近似を用いることができる。本発明の範囲ではRe>38、000となるので、乱流域となることからFr数近似を適用した。 When the equation of motion is made dimensionless, (inertia term) + (viscosity term) / Re + (external force term) = 0, and Fr enters the external force term as (1 / Fr 2 ). As Re increases, (viscosity term) / Re decreases, so Re is eliminated from the equation of motion. Re> 4000 or more and a normal turbulent region, and Fr number approximation can be used. In the scope of the present invention, Re> 38,000, so that the Fr number approximation is applied because it is a turbulent region.
インゴットの下注ぎ鋳造における実機と模型実験のフルード数の一致させ、実機の代表寸法と水モデル模型の代表寸法比を5:1、すなわち1/5の縮尺モデルとした場合、フルード数一致の観点から、V/L0.5を同じにする必要がある。縮尺を1/λ(=1/5)とすると、VR/LR 0.5=VM/LM 0.5(ここでRは実機、Mはモデルを示す。)となる。
VM/VR=LM 0.5/LR 0.5=1/λ0.5=1/50.5≒0.447となる。つまり、VM≒0.447VRとなる。したがって、縮尺1/5の模型実験では、0.447倍の流速でFr数の一致が得られることになる。ここで、流量をQ、時間をTとすると、
TR=LR/VR
TM=LM/VM
TR=TM・LR/LM・VM/VR=TMλ0.5
QM/QR=(LM 3/TM)/(LR 3/TR)=λ−3・λ0.5=λ−2.5
となり、この結果、水モデルの流量は、実機の流量の1/52.5=0.0179倍となる。また、水モデルの流量QM(L/min)を実機スループットWR(t/min)に換算する場合、溶鋼の比重を7t/m3とすると、上述した式(A)となる。
When the fluid number of the actual machine and the model experiment in ingot casting is matched, and the representative dimension ratio of the actual machine and the water model is 5: 1, that is, 1/5 scale model, the fluid number is the same. From the viewpoint, V / L 0.5 needs to be the same. When the scale is 1 / λ (= 1/5), V R / L R 0.5 = V M / L M 0.5 (where R is an actual machine and M is a model).
The V M / V R = L M 0.5 / L R 0.5 = 1 / λ 0.5 = 1/5 0.5 ≒ 0.447. In other words, the V M ≒ 0.447V R. Therefore, in a 1/5 scale model experiment, Fr number coincidence can be obtained at a flow rate of 0.447 times. Here, if the flow rate is Q and the time is T,
T R = L R / V R
T M = L M / V M
T R = T M · L R / L M · V M / V R = T M λ 0.5
Q M / Q R = (L M 3 / T M) / (L R 3 / T R) = λ -3 · λ 0.5 = λ -2.5
As a result, the flow rate of the water model is 1/5 2.5 = 0.0179 times the flow rate of the actual machine. Further, when the flow rate QM (L / min) of the water model is converted into the actual machine throughput W R (t / min), the above formula (A) is obtained when the specific gravity of the molten steel is 7 t / m 3 .
表1〜5は、本発明の下注造塊方法に基づいて実験を行った例と、本発明の下注造塊方法とは異なる方法によって実験を行った例とをまとめたものである。 Tables 1 to 5 summarize an example in which an experiment was performed based on the ingot ingot casting method of the present invention and an example in which an experiment was performed by a method different from the ingot ingot ingot method of the present invention.
40t鋼塊用鋳型の実機の1/5のスケールの模型を用いて実験を行った。水モデルでは、鋳型は、透明ポリ塩化ビニル製であって、上部が底部よりも広がった上広鋳型とした。詳しくは、底面は、440×220mm、上面は、480×260mm、高さは、560mm、注入管の内径は、26mmφとした。湯道10b(左側の湯道)の長さは、985mm、湯道10a側の長さ(全体の長さ)は、395mm、985mmとした。湯道1
0a側の全長と、湯道10b側の全長との比は、1:2.3〜1:2.7の範囲とした。
The experiment was conducted using a 1/5 scale model of the actual 40t steel ingot mold. In the water model, the mold was made of transparent polyvinyl chloride, and the upper mold was wider than the bottom. Specifically, the bottom surface was 440 × 220 mm, the top surface was 480 × 260 mm, the height was 560 mm, and the inner diameter of the injection tube was 26 mmφ. The length of the runner 10b (the left runner) was 985 mm, and the length of the runner 10a (the overall length) was 395 mm and 985 mm. Yudo 1
The ratio of the total length on the 0a side to the total length on the runner 10b side was in the range of 1: 2.3 to 1: 2.7.
第2湯道内径D2は、14mmφ、16mmφ、18mmφとした。第1湯道内径D1は、11mmφ、13mmφ、15mmφ、16mmφ、18mmφとした。細径部長さL1は、114mm〜395mmした。離間距離L2は、0mm〜80mmとした。上述した寸法は、いずれも内寸である。なお、
注湯流量Qは、7.5L/min(実機で2.93t/min相当)、15.0L/min(実機で5.85t/min相当)、22.5Lmin(実機で8.78t/min相当)とした。なお、水モデルにおける注湯流量は、注入管に水を注入する前の配管に取り付けた流量計で注湯流量を計測した値である。
The second runner inner diameter D2 was 14 mmφ, 16 mmφ, and 18 mmφ. The first runner inner diameter D1 was 11 mmφ, 13 mmφ, 15 mmφ, 16 mmφ, and 18 mmφ. The small-diameter portion length L1 was 114 mm to 395 mm. The separation distance L2 was set to 0 mm to 80 mm. All the dimensions described above are internal dimensions. In addition,
The pouring flow rate Q is 7.5 L / min (equivalent to 2.93 t / min in the actual machine), 15.0 L / min (equivalent to 5.85 t / min in the actual machine), 22.5 Lmin (equivalent to 8.78 t / min in the actual machine). ). Note that the pouring flow rate in the water model is a value obtained by measuring the pouring flow rate with a flow meter attached to the pipe before pouring water into the pouring pipe.
水モデルでは、透明な鋳型内に赤色インクで着色した水の湯面上昇速度をデジタルムービーカメラで撮影し、撮影した画像を再生し、一定時間ごとの湯面位置から上昇速度を求め、注入流量に換算した。注入流量は、例えば、2.5L/min(実機で0.98t/min相当)、5.0L/min(実機で1.95t/min相当)、7.5L/min(実機で2.93t/min相当)となった。 In the water model, the water level rising speed of water colored with red ink in a transparent mold is photographed with a digital movie camera, the captured image is reproduced, and the rate of rise is determined from the position of the level at regular intervals. Converted into The injection flow rate is, for example, 2.5 L / min (corresponding to 0.98 t / min in the actual machine), 5.0 L / min (corresponding to 1.95 t / min in the actual machine), 7.5 L / min (2.93 t / in in the actual machine). min equivalent).
水モデルでは、最大注入流量差が7.1%以下で且つスプラッシュが発生していない場合を良好「○」、最大注入流量差が7.1%を超える、或いは、スプラッシュが発生している場合を不良「×」とし、総合評価を行った。
表に示すように、注入管に注入する注湯流量(実機換算値)が2〜10t/minであって、第2湯道内径D2に対して、第1湯道内径D1(細径部の内径D1)が式(1a)〜式(3a)を満たし、細径部の湯道長さL1が式(4a)を満たし、細径部の終端位置と鋳型の注入口の距離(離間距離)L2が式(5a)を満たしている場合、最大注入流量差が7.1%以下で且つスプラッシュも発生しなかった。
In the water model, the case where the maximum injection flow rate difference is 7.1% or less and no splash occurs is good, “○”, the maximum injection flow rate difference exceeds 7.1%, or the splash is generated Was evaluated as “bad”, and a comprehensive evaluation was performed.
As shown in the table, the pouring flow rate (actual machine equivalent value) to be injected into the injection pipe is 2 to 10 t / min, and the first runner inner diameter D1 (of the small diameter portion of the second runner inner diameter D2). The inner diameter D1) satisfies the expressions (1a) to (3a), the runner length L1 of the small diameter portion satisfies the expression (4a), and the distance (separation distance) L2 between the end position of the small diameter portion and the casting inlet of the mold When satisfying formula (5a), the maximum injection flow rate difference was 7.1% or less and no splash occurred.
一方、第1湯道内径D1(細径部の内径D1)が式(1a)〜式(3a)を満たさなかったり、細径部の湯道長さL1が式(4a)を満たさなかったり、離間距離L2が式(5a)を満たさない場合、最大注入流量差が7.1%を超えたり、スプラッシュが発生した。
例えば、実験1、2、11〜13、26〜28では、離間距離L2が式(5a)を満たしていないため、スプラッシュが発生した。また、実験41〜49では、第1湯道内径D1(細径部の内径D1)が式(1a)を満たさなかったため、最大注入流量差が7.1%を超えてしまった。また、実験79では、細径部の湯道長さL1が式(4a)を満たさなかったため、最大注入流量差が7.1%を超えてしまった。
以上、本発明によれば、各鋳型間の湯面高さの差を少なくしつつ、高品質の鋼塊を製造することができる。
On the other hand, the first runner inner diameter D1 (the inner diameter D1 of the narrow diameter portion) does not satisfy the formulas (1a) to (3a), the runner length L1 of the narrow diameter portion does not satisfy the formula (4a), or is separated. When the distance L2 did not satisfy the formula (5a), the maximum injection flow rate difference exceeded 7.1% or splash occurred.
For example, in Experiments 1, 2, 11 to 13, and 26 to 28, since the separation distance L2 does not satisfy the formula (5a), splash occurred. Further, in Experiments 41 to 49, the first runner inner diameter D1 (the inner diameter D1 of the narrow diameter portion) did not satisfy the formula (1a), and thus the maximum injection flow rate difference exceeded 7.1%. In Experiment 79, the runner length L1 of the narrow diameter portion did not satisfy the formula (4a), and thus the maximum injection flow rate difference exceeded 7.1%.
As described above, according to the present invention, a high-quality steel ingot can be manufactured while reducing the difference in the molten metal surface height between the molds.
なお、今回開示された実施の形態はすべての点で例示であって制限的なものではないと考えられるべきである。本発明の範囲は上記した説明ではなくて特許請求の範囲によって示され、特許請求の範囲と均等の意味及び範囲内でのすべての変更が含まれることが意図される。 The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
1 下注造塊装置
2 溶鋼
3 取鍋
4 注入管
5 湯道
6 鋳型
6a 第1鋳型
6b 第2鋳型
7 定盤
8 注入口
9 細径部
10a 湯道
10b 湯道
11 細径部
12a 終端部
13 注入口
14 大径部
DESCRIPTION OF SYMBOLS 1 Lower pouring apparatus 2 Molten steel 3 Ladle 4 Injection pipe 5 Runway 6 Mold 6a 1st mold 6b 2nd mold 7 Surface plate 8 Inlet 9 Narrow diameter part 10a Runway 10b Runway 11 Narrow diameter part 12a Termination part 13 Inlet 14 Large diameter part
Claims (1)
前記第1鋳型と第2鋳型とが全て同じ形状であり、
前記第1鋳型の鋳型と第2鋳型の注入管側の鋳型が注入管に対し対称に配置されていて、
前記第2鋳型の注入管側の鋳型と他の鋳型との距離が湯道の長さに対して無視できる程度の距離であり、
前記第1鋳型側の湯道であって狭くなる細径部の内径D1(mm)が55〜90、前記第2鋳型側の湯道内径D2(mm)が70〜90、及び前記第1鋳型側の細径部以外の湯道内径D3(mm)が第2鋳型側の湯道内径D2と等しくされており、
前記鋳型サイズが40t〜50tとされている場合に、
前記注入管に注入する注湯流量は2〜10t/minとし、前記第1鋳型側の湯道長さと第2鋳型側の湯道長さとの比を1:2.3〜1:2.7の範囲に設定されており、
前記第2鋳型側の湯道内径D2(mm)に対して、前記第1鋳型側の湯道であって狭くなる細径部の内径D1(mm)が式(1)〜式(3)を満たし、
前記細径部の湯道長さL1(mm)が式(4)を満たし、前記細径部の終端位置と鋳型の注入口の距離L2(mm)とが式(5)を満たすことを特徴とする下注造塊方法。
The first mold and the second mold are all the same shape,
The casting mold on the first casting mold side and the casting mold side on the second casting mold side are arranged symmetrically with respect to the injection pipe;
The distance between the mold on the injection pipe side of the second mold and the other mold is a distance that can be ignored with respect to the length of the runner,
The inner diameter D1 (mm) of the narrow portion that is the runner on the first mold side and becomes narrower is 55 to 90, the runner inner diameter D2 (mm) on the second mold side is 70 to 90, and the first mold. The runner inner diameter D3 (mm) other than the narrow portion on the side is made equal to the runner inner diameter D2 on the second mold side,
When the mold size is 40t to 50t,
The pouring flow rate to be injected into the injection pipe is 2 to 10 t / min, and the ratio of the runner length on the first mold side to the runner length on the second mold side is in the range of 1: 2.3 to 1: 2.7. Is set to
With respect to the runner inner diameter D2 (mm) on the second mold side, the inner diameter D1 (mm) of the narrow diameter portion which is the runner on the first mold side and becomes narrower is expressed by the following formulas (1) to (3). Meet,
The runner length L1 (mm) of the narrow diameter portion satisfies the formula (4), and the end position of the narrow diameter portion and the distance L2 (mm) between the mold inlet satisfy the formula (5). The method of ingot casting.
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JPS6043826B2 (en) * | 1977-10-27 | 1985-09-30 | 日本鋼管株式会社 | Runner pipes of bottom pouring ingot making equipment |
JPS5462121A (en) * | 1977-10-27 | 1979-05-18 | Nippon Kokan Kk | Tapping tube of bottom casting installation |
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