JP2016135493A - Mold powder for continuous casting of steel - Google Patents

Mold powder for continuous casting of steel Download PDF

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JP2016135493A
JP2016135493A JP2015010988A JP2015010988A JP2016135493A JP 2016135493 A JP2016135493 A JP 2016135493A JP 2015010988 A JP2015010988 A JP 2015010988A JP 2015010988 A JP2015010988 A JP 2015010988A JP 2016135493 A JP2016135493 A JP 2016135493A
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JP6394414B2 (en
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塚口 友一
Yuichi Tsukaguchi
友一 塚口
達一 棚橋
Tatsuichi Tanahashi
達一 棚橋
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Nippon Steel Corp
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Nippon Steel and Sumitomo Metal Corp
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Abstract

PROBLEM TO BE SOLVED: To restrain sintering of mold powders and to prevent excess growth of slag rim in a casting mold.SOLUTION: There is provided the mold powder 3 for continuous casting of steel including MgO, CaO, SrO, BaO and SiOas main components and having a total main component concentration of 60 atom% or more. The base material of the mold powder 3 having the total main component concentration of 60 atom% or more contains at least one of group 2 metal carbonates such as carbonates of magnesium, calcium, strontium and barium. Total concentration of group 2 metal oxides generating by thermal decomposition of group 2 metal carbonates is controlled to be in the range of 7 to 30 atom%. SiOderived from soda-lime glass dust included in the base material is made to account for 50 mass% or more of total amount of SiOincluded in the mold powder.EFFECT: Problem accompanying slag rim thickening is remedied without taking an operation risk.SELECTED DRAWING: Figure 1

Description

本発明は、鋼等の高温溶融金属の連続鋳造に用いられる潤滑保温剤であるモールドパウダーに関するものである。   The present invention relates to a mold powder which is a lubricating heat insulating agent used for continuous casting of high-temperature molten metal such as steel.

図1に示すように、鋼等の連続鋳造において、鋳型1に供給された溶融金属2の湯面上に添加されたモールドパウダー3は、溶融金属2の熱で溶けて溶融金属2の湯面上で溶融スラグ4の層を形成する。   As shown in FIG. 1, in continuous casting of steel or the like, the mold powder 3 added onto the molten metal 2 supplied to the mold 1 is melted by the heat of the molten metal 2 to melt the molten metal 2. A layer of molten slag 4 is formed above.

形成された溶融スラグ4は、鋳型1と鋳片5との間隙に流入してフィルム6を形成する。このフィルム6は、鋳型1と鋳片5の焼き付きを防止する潤滑の役割と、鋳片5から鋳型1への熱流束を制御する冷却調整の役割を担う。   The formed molten slag 4 flows into the gap between the mold 1 and the cast slab 5 to form a film 6. The film 6 plays a role of lubrication for preventing seizure of the mold 1 and the slab 5 and a role of cooling adjustment for controlling a heat flux from the slab 5 to the mold 1.

モールドパウダー3は、一般に、融点あるいは軟化温度の異なる複数種の原料を混合しているので、溶融開始段階では低融点原料が先に溶けて高融点原料を繋げるバインダーとして作用し、焼結体を形成した後、完全溶融に至る。   Since the mold powder 3 is generally a mixture of a plurality of types of raw materials having different melting points or softening temperatures, the low melting point raw material melts first in the melting start stage and acts as a binder to connect the high melting point raw materials. After forming, complete melting occurs.

溶融開始段階で形成される焼結体は、鋳型1の内壁面に沿って連続したスラグリム(スラグベアとも言う)7を形成する。スラグリム7は、鋳型振動(オシレーション)と相まって溶融スラグ4の流入を促進するポンプ作用を果たすが、スラグリム7が過大に成長すると、自重によって徐々に鋳型1の内側へ倒れ込んで、溶融スラグ4の流入経路を塞いだり、鋳片5の先端部を押し込んだりする悪弊を生じるようになる。   The sintered body formed at the melting start stage forms a continuous slag rim (also referred to as a slag bear) 7 along the inner wall surface of the mold 1. The slag rim 7 performs a pumping action that promotes the inflow of the molten slag 4 in combination with the mold vibration (oscillation). However, when the slag rim 7 grows excessively, the slag rim 7 gradually falls to the inside of the mold 1 by its own weight, and the molten slag 4 A bad effect of closing the inflow path or pushing the tip of the slab 5 occurs.

そこで、従来から、スラグリムの肥大化を抑制する技術が、提案されている。
例えば特許文献1,2では、モールドパウダー中のアルカリ金属酸化物の濃度を低減することによって、焼結のバインダーとなる低融点液相の生成そのものを抑制する発明が提案されている。また、特許文献3では、モールドパウダーの骨材となるカーボンの種類や配合量を工夫することによって焼結を抑制する発明が提案されている。
Thus, conventionally, a technique for suppressing the enlargement of the slag rim has been proposed.
For example, Patent Documents 1 and 2 propose inventions that suppress the generation of a low-melting-point liquid phase that becomes a binder for sintering by reducing the concentration of alkali metal oxide in the mold powder. Patent Document 3 proposes an invention that suppresses sintering by devising the type and blending amount of carbon to be an aggregate of mold powder.

特許文献1〜3で提案されたモールドパウダーはいずれも有効である。
しかしながら、アルカリ金属酸化物の濃度を低減する場合、モールドパウダーの粘性や結晶化温度といった物性値の調整が難しくなるので、全てのモールドパウダーに適用できるわけではない。また、カーボンの種類や配合量の工夫も、モールドパウダーの粒形状が中空顆粒である場合には、造粒の都合上、使えるカーボンの種類が制限されるので、活用が難しい。
Any of the mold powders proposed in Patent Documents 1 to 3 is effective.
However, when the concentration of the alkali metal oxide is reduced, it is difficult to adjust the physical property values such as the viscosity and crystallization temperature of the mold powder, so that it cannot be applied to all mold powders. In addition, when the shape of the mold powder is a hollow granule, the type of carbon and the amount of carbon are difficult to use because the types of carbon that can be used are limited for granulation.

特許第2985671号公報Japanese Patent No. 2985671 特許第3637895号公報Japanese Patent No. 3637895 特開平11−10297号公報Japanese Patent Laid-Open No. 11-10297

本発明が解決しようとする問題点は、スラグリムの過大成長を防止するために、アルカリ金属酸化物の濃度を低減する場合、物性値の調整が難しくなるので、全てのモールドパウダーに適用できるわけではないという点である。また、カーボンの種類や配合量の工夫も、モールドパウダーの粒形状が中空顆粒である場合は、造粒の都合上、使えるカーボンの種類が制限されるので、活用が難しいという点である。   The problem to be solved by the present invention is that, when the concentration of alkali metal oxide is reduced in order to prevent overgrowth of slag rim, it is difficult to adjust the physical property value, so it cannot be applied to all mold powders. There is no point. In addition, when the mold powder has a hollow granule, the type of carbon and the amount of carbon are also difficult to use because the type of carbon that can be used is limited for granulation.

本発明は、上記技術的背景に鑑みて成されたものであり、化学組成の変更やカーボン原料の工夫に頼ることなくモールドパウダーの焼結を抑制し、鋳型内におけるスラグリムの過大な成長を防止することができるモールドパウダーの提供を目的とするものである。   The present invention has been made in view of the above technical background, and suppresses the sintering of mold powder without relying on the change of chemical composition or the device of carbon material, and prevents excessive growth of slag rim in the mold. An object of the present invention is to provide a mold powder that can be used.

鋼の連続鋳造用モールドパウダーは、通常、第二族金属の塩基性酸化物であるMgO ,CaO ,SrO ,BaO と、酸性酸化物であるSiO2を主成分として含有する。その理由は、これらの組み合わせが比較的安価に凝固温度や粘度といった物性値を調整するのに好適だからである。 The mold powder for continuous casting of steel usually contains MgO 2, CaO 2, SrO 2, BaO, which are basic oxides of Group 2 metals, and SiO 2 , which is an acidic oxide, as main components. The reason is that these combinations are suitable for adjusting physical properties such as solidification temperature and viscosity at a relatively low cost.

発明者らは、前記主成分の原料として、第二族金属の炭酸塩である炭酸マグネシウム、炭酸カルシウム、炭酸ストロンチウム、炭酸バリウム、にソーダ石灰ガラス粉を組み合わせて、それぞれある割合以上用いることによって、モールドパウダーが鋳型内で焼結して生じるスラグリムの気孔率が高まり、強度が低下することを見出した。   The inventors use magnesium carbonate, calcium carbonate, strontium carbonate, barium carbonate, and soda lime glass powder, which are carbonates of Group 2 metals, as a raw material of the main component, respectively, by using more than a certain ratio, respectively. It has been found that the porosity of the slag rim generated by sintering the mold powder in the mold increases and the strength decreases.

強度の低いスラグリムは鋳型内で自己崩壊するので、スラグリムの気孔率を高めるとスラグリムが過大に成長することを防止できるのである。その理由は、これら炭酸塩が熱分解して炭酸ガスを放出する温度とソーダ石灰ガラス粉が軟化する温度が、共に800〜1000℃の間にあるので、炭酸ガスによる発泡作用がソーダ石灰ガラス粉に作用して焼結体の気孔率が高まるためと考えられる。ソーダ石灰ガラス粉は溶融時にも高い粘度を保つので、炭酸塩の分解によって生じたガスを取り込んで発泡し、焼結体の気孔率を増大させる能力が高いと考えられる。   Since the slag rim having low strength self-collapses in the mold, the slag rim can be prevented from growing excessively when the porosity of the slag rim is increased. The reason for this is that the temperature at which these carbonates are thermally decomposed to release carbon dioxide and the temperature at which soda lime glass powder is softened are between 800-1000 ° C., so that the foaming action by carbon dioxide is the soda lime glass powder. This is thought to be due to the fact that the porosity of the sintered body is increased by acting on the above. Since soda lime glass powder maintains a high viscosity even when melted, it is considered that the soda lime glass powder has a high ability to take in and foam a gas generated by the decomposition of carbonate and increase the porosity of the sintered body.

本発明は、上記の発明者らの知見を基にしており、モールドパウダーの主成分であるMgO ,CaO ,SrO,BaO およびSiO2の原料に、第二族金属炭酸塩とソーダ石灰ガラス粉を組み合わせて、規定濃度あるいは割合以上用いることによって、鋳型内におけるスラグリムの過大な成長を防止することをその骨子としている。 The present invention is based on the knowledge of the above-mentioned inventors, and Group 2 metal carbonate and soda lime glass powder are used as raw materials for MgO, CaO, SrO, BaO and SiO 2 which are the main components of mold powder. The essential point is to prevent excessive growth of the slag rim in the mold by using a combined concentration or a proportion or more in combination.

すなわち、本発明は、
鋼等の高温溶融金属の連続鋳造に用いられ、第二族金属酸化物であるMgO ,CaO ,SrO,BaO とSiO2を主成分とし、これら主成分の合計濃度が60atomic%以上である鋼の連続鋳造用モールドパウダーであって、
前記主成分の合計濃度が60atomic%以上であるモールドパウダーの基材原料中に、第二族金属炭酸塩である炭酸マグネシウム、炭酸カルシウム、炭酸ストロンチウム、炭酸バリウムの内、少なくとも1種類以上を含有し、これら第二族金属炭酸塩が熱分解して生じる前記主成分となる第二族金属酸化物の合計濃度が7〜30atomic%の範囲内にあり、
かつ、前記基材原料中に含有したソーダ石灰ガラス粉に由来するSiO2が、モールドパウダーに含まれるSiO2の総量の50mass%以上を占めることを最も主要な特徴としている。
That is, the present invention
It is used for continuous casting of high-temperature molten metals such as steel, and is mainly composed of group 2 metal oxides MgO, CaO, SrO, BaO and SiO 2 and the total concentration of these main components is 60 atomic% or more. Mold powder for continuous casting,
The base material of the mold powder in which the total concentration of the main components is 60 atomic% or more contains at least one of the group 2 metal carbonates magnesium carbonate, calcium carbonate, strontium carbonate, and barium carbonate. The total concentration of the Group 2 metal oxides, which are the main components generated by the thermal decomposition of these Group 2 metal carbonates, is in the range of 7 to 30 atomic%.
And the main feature is that SiO 2 derived from soda-lime glass powder contained in the base material occupies 50 mass% or more of the total amount of SiO 2 contained in the mold powder.

本発明において、MgO ,CaO ,SrO,BaO とSiO2を主成分とするとは、これら酸化物の合計濃度が60atomic%以上であることと定義する。これら酸化物の合計濃度の上限は100atomic%であることは言うまでもない。 In the present invention, MgO 2, CaO 2, SrO, BaO 2 and SiO 2 as main components are defined as the total concentration of these oxides being 60 atomic% or more. Needless to say, the upper limit of the total concentration of these oxides is 100 atomic%.

本発明の鋼の連続鋳造用モールドパウダーにおけるスラグリム成長の抑制効果は、モールドパウダーの主成分であるMgO ,CaO ,SrO,BaO の原料にこれらの炭酸塩を用い、炭酸塩由来のMgO ,CaO ,SrO,BaO の合計濃度が7atomic%以上、より好ましくは10atomic% 以上の場合に発揮される。   The effect of suppressing the growth of slag rim in the mold powder for continuous casting of the steel of the present invention is that these carbonates are used as raw materials for MgO, CaO, SrO, BaO, which are the main components of the mold powder, and MgO, CaO, This is exhibited when the total concentration of SrO and BaO is 7 atomic% or more, more preferably 10 atomic% or more.

しかしながら、これら炭酸塩由来のMgO ,CaO ,SrO ,BaO の合計濃度が30atomic%を超えると、炭酸塩分解に伴う吸熱がモールドパウダーの溶鋼湯面保温作用を損なうので好ましくない。   However, if the total concentration of MgO, CaO, SrO, and BaO derived from these carbonates exceeds 30 atomic%, the endotherm accompanying the decomposition of the carbonates is not preferable because the heat-insulating action of the mold powder is impaired.

ところで、一般的にモールドフラックスの原料として使われる炭酸塩には、第二族金属炭酸塩の他に、Na2CO3などのアルカリ金属炭酸塩がある。 Incidentally, carbonates generally used as a raw material for mold flux include alkali metal carbonates such as Na 2 CO 3 in addition to Group 2 metal carbonates.

しかしながら、アルカリ金属炭酸塩は、分解時にSiO2と反応して800℃程度で液相を生じ、それをバインダーとしてモールドフラックスの焼結収縮が促進されてしまう側面を持つ。 However, the alkali metal carbonate has a side surface that reacts with SiO 2 at the time of decomposition to form a liquid phase at about 800 ° C., and the sintering shrinkage of the mold flux is promoted by using it as a binder.

これに対して、第二族金属炭酸塩は、分解時にSiO2と反応して800℃程度で液相を生じることがなく、バインダーとしてモールドフラックスの焼結収縮を促進せずにスラグリムの形成を抑制できる。 On the other hand, the Group 2 metal carbonate does not react with SiO 2 at the time of decomposition to form a liquid phase at about 800 ° C., and does not promote the sintering shrinkage of the mold flux as a binder, thereby forming a slag rim. Can be suppressed.

そこで、本発明では、スラグリム成長抑制の観点から好適である第二族金属炭酸塩を利用することとしている。   Therefore, in the present invention, a Group 2 metal carbonate that is suitable from the viewpoint of suppressing the growth of slag rim is used.

一方の主成分であるSiO2に関しては、その原料の50mass%以上、より好ましくは60mass%以上をソーダ石灰ガラス粉とすれば、炭酸塩分解によるガス発生とソーダ石灰ガラス粉軟化の相乗効果によって十分な効果が得られる。ソーダ石灰ガラス粉に由来するSiO2が、モールドパウダーに含まれるSiO2の総量に占める割合の上限は100mass%であることは言うまでもない。 With regard to SiO 2 as one main component, if 50 mass% or more, more preferably 60 mass% or more of the raw material is made soda lime glass powder, it is sufficient due to the synergistic effect of gas generation by carbonate decomposition and soda lime glass powder softening. Effects can be obtained. Needless to say, the upper limit of the proportion of SiO 2 derived from soda-lime glass powder in the total amount of SiO 2 contained in the mold powder is 100 mass%.

ところで、ソーダ石灰ガラスとは、最も広範に使われているガラスであり、その組成は70〜73mass%SiO2,1〜2mass%Al2O3 ,13〜15mass%Na2O,7〜12mass%CaO のものが一般的であるが、Na2Oの一部をK2O に置き換えたものや数%程度のMgO を含むもの、 着色のために微量の遷移金属酸化物などを加えたものもある。本発明では、このようなソーダ石灰ガラスを数μm 〜数10μm 程度の粒径に粉砕したものを原料に用いる。この粒度は他の基材原料と同等である。 By the way, soda lime glass is the most widely used glass, and its composition is 70 to 73 mass% SiO 2 , 1 to 2 mass% Al 2 O 3 , 13 to 15 mass% Na 2 O, 7 to 12 mass%. CaO is generally used, but some of which Na 2 O is replaced with K 2 O, some containing about several percent MgO, and some with addition of a small amount of transition metal oxide for coloring. is there. In the present invention, such a soda-lime glass pulverized to a particle size of about several μm to several tens of μm is used as a raw material. This particle size is equivalent to other base material.

本発明で規定しないモールドフラックスの基材原料としては、CaO およびSiO2を主に含む原料としてポルトランドセメントやウォラストナイト、SiO2原料として珪砂や珪藻土、Al2O3 の原料としてアルミナ粉、MgO の原料としてマグネシア粉(マグネシアクリンカ)、Na2O原料としてソーダ灰(炭酸ナトリウム)、F 原料としてホタル石など、一般的な原料を用いればよい。 The substrate material of the mold flux which is not defined in the present invention, portland cement and wollastonite the CaO and SiO 2 as raw materials containing mainly silica sand and diatomaceous earth as a SiO 2 raw material, alumina powder as a raw material for Al 2 O 3, MgO Common raw materials such as magnesia powder (magnesia clinker), sodium ash (sodium carbonate) as Na 2 O raw material, and fluorite as F raw material may be used.

また、モールドフラックスは、溶融速度調整用の骨材原料として、カーボンブラックやコークス粉などの炭素質原料を数mass%程度配合するが、これら骨材原料の配合については、本発明では特に規定しない。   In addition, the mold flux contains about several mass% of a carbonaceous raw material such as carbon black or coke powder as an aggregate raw material for adjusting the melting rate. However, the composition of the aggregate raw material is not particularly defined in the present invention. .

本発明において、濃度をatomic%で表すのは、原子量が大きく異なるマグネシウム〜バリウムまでの第二族金属を含む原料の濃度をmass%で表すと、濃度と配合効果との関係が原料毎に大きく異なってしまうためである。   In the present invention, the concentration is expressed in atomic%. When the concentration of a raw material containing a group II metal from magnesium to barium with greatly different atomic weights is expressed in mass%, the relationship between the concentration and the mixing effect is large for each raw material. This is because they are different.

本発明のモールドパウダーは、多くの炭酸塩を含有する配合となるので、単に原料粉末を混合して製品とした場合、鋳型内で炭酸塩の熱分解によって発生するガスが原料粉末を舞い上げ、作業環境汚染を引き起こす場合がある。   Since the mold powder of the present invention has a composition containing many carbonates, when simply mixing raw material powders into a product, the gas generated by pyrolysis of carbonates in the mold soars the raw material powders, May cause work environment contamination.

そこで、本発明のモールドパウダーは、基材原料にカーボンを主とした骨材原料を加えて混合したものを水で練ってスラリーにした後、顆粒状に成形した製品とすることが望ましい。   Therefore, it is desirable that the mold powder of the present invention is a product in which a material obtained by adding an aggregate raw material mainly composed of carbon to a base material is kneaded with water to form a slurry, and then formed into granules.

顆粒の粒形状は、俵状、丸粒、中空丸粒、いずれであっても構わない。また、顆粒の大きさ(短径)は特に限定されないが、一般的には、0.3mm〜1.5mm程度のものを使用する。   The particle shape of the granule may be any of a bowl shape, a round particle, and a hollow round particle. The size (minor axis) of the granule is not particularly limited, but generally about 0.3 mm to 1.5 mm is used.

本発明では、モールドフラックスの化学組成を保ったまま、原料系の変更によって、スラグリムの成長を抑制できるので、操業上のリスクを負うことなく、スラグリムの肥大化にともなう問題を改善することができる。しかも、それに用いる原料が、リサイクル原料であるガラス粉など比較的安価なものであることも、本発明の優れた点である。   In the present invention, the growth of the slag rim can be suppressed by changing the raw material system while maintaining the chemical composition of the mold flux, so that the problems associated with the enlargement of the slag rim can be improved without incurring operational risks. . Moreover, it is also an excellent point of the present invention that the raw material used for it is relatively inexpensive such as glass powder which is a recycled raw material.

連続鋳造中の鋳型内の状況を説明する図である。It is a figure explaining the condition in the casting_mold | template in continuous casting. 本発明の実施例と比較例におけるスラグリムの厚さを示した図である。It is the figure which showed the thickness of the slag rim in the Example and comparative example of this invention.

本発明では、化学組成の変更やカーボン原料の工夫に頼ることなくモールドパウダーの焼結を抑制し、鋳型内におけるスラグリムの過大な成長を防止するという目的を、モールドフラックスの化学組成を保ったまま、原料系を変更することで実現した。   The purpose of the present invention is to suppress the sintering of the mold powder without relying on a change in the chemical composition or the device of the carbon raw material, and to prevent excessive growth of the slag rim in the mold, while maintaining the chemical composition of the mold flux. This was realized by changing the raw material system.

以下に、本発明の実施例を比較例と対比して示しながら、本発明について具体的に説明する。   Hereinafter, the present invention will be described in detail while showing examples of the present invention in comparison with comparative examples.

下記表1には、本発明の実施例と比較例の基材組成及びその濃度、基材組成の主成分であるMgO ,CaO ,SrO ,BaO とSiO2の合計濃度、炭酸塩由来の基材の濃度、炭酸塩のMgO ,CaO ,SrO ,BaO の合計濃度、全SiO2中のソーダ石灰ガラス粉由来の割合、製品の粒形状を示している。 Table 1 below shows base material compositions and concentrations of Examples and Comparative Examples of the present invention, total concentrations of MgO, CaO, SrO, BaO and SiO 2 as main components of the base material composition, base materials derived from carbonates. concentration, MgO carbonate, CaO, SrO, total concentration of BaO, proportions from soda-lime glass powder of the total SiO 2, shows the particle shape of the product.

Figure 2016135493
Figure 2016135493

表1中のAは、本発明の請求項1を満たすモールドフラックス、BおよびCは、本発明の請求項1および請求項2を満たすモールドフラックスの実施例を示す。   In Table 1, A represents a mold flux satisfying claim 1 of the present invention, and B and C represent examples of mold flux satisfying claims 1 and 2 of the present invention.

これらの実施例A〜Cにおいては、SiO2原料の多くを占めるソーダ石灰ガラス粉が軟化する温度域において第二族金属炭酸塩の分解によりガスが発生して焼結体の気孔率が高まり、後述する連続鋳造試験結果のようにスラグリムの成長が効果的に抑制される。 In these Examples A to C, gas is generated by decomposition of the Group 2 metal carbonate in the temperature range where the soda lime glass powder occupying most of the SiO 2 raw material is softened, and the porosity of the sintered body is increased. The growth of the slag rim is effectively suppressed as in the continuous casting test result described later.

一方、表1中のD〜Fは、本発明の請求項を満たさないモールドフラックスの比較例を示す。   On the other hand, D to F in Table 1 show comparative examples of mold fluxes that do not satisfy the claims of the present invention.

これらの比較例D,E,Fは、それぞれ実施例A,B,Cと同じ化学組成を有するモールドフラックスであるが、第二族金属炭酸塩やソーダ石灰ガラス粉の配合が本発明の規定を満たさないので、スラグリムが成長しやすい例である。   These Comparative Examples D, E, and F are mold fluxes having the same chemical composition as Examples A, B, and C, respectively, but the composition of Group 2 metal carbonate and soda lime glass powder stipulates the provisions of the present invention. This is an example in which the slag rim is likely to grow because it does not satisfy.

また表1中のGは、主成分(MgO +CaO +SrO +BaO +SiO2)の合計濃度が本発明で規定する範囲を満たさないので、本発明の効果を発揮しえない比較例である。 Further, G in Table 1 is a comparative example in which the effect of the present invention cannot be exhibited because the total concentration of the main components (MgO + CaO + SrO + BaO + SiO 2 ) does not satisfy the range defined by the present invention.

次に、実施例Cおよび比較例Fのモールドフラックスを実際の連続鋳造に供した結果について説明する。   Next, the results of subjecting the mold fluxes of Example C and Comparative Example F to actual continuous casting will be described.

横断面が300mm×400mmの矩形断面鋳型に、内径が80mm、外径が150mmの浸漬ノズルを通して下記表2に示した化学組成を有する高炭素鋼の溶鋼を供給しながら、0.7m/minの鋳造速度で、280分間に亘って連続鋳造した後、鋳型内で成長したスラグリムの厚みt(図1参照)を測定した。スラグリムは、鋳造の終わった鋳型内から採取し、矩形断面鋳型のコーナー部2箇所とコーナー部から100mm離れた部位2箇所の厚みを測定して、その厚みデータを得た。   While supplying molten steel of high carbon steel having the chemical composition shown in Table 2 below through a submerged nozzle having an inner diameter of 80 mm and an outer diameter of 150 mm into a rectangular cross-section mold having a cross section of 300 mm × 400 mm, 0.7 m / min After continuous casting for 280 minutes at the casting speed, the thickness t (see FIG. 1) of the slag rim grown in the mold was measured. The slag rim was collected from the cast mold, and the thickness data were obtained by measuring the thickness of two corner portions of the rectangular cross-section mold and two portions 100 mm away from the corner portions.

Figure 2016135493
Figure 2016135493

その結果、図2に示すように、実施例Cのモールドフラックスを使用した場合の平均スラグリム厚みは、比較例Fのモールドフラックスを使用した場合の半分程度に低減した。   As a result, as shown in FIG. 2, the average slag rim thickness when the mold flux of Example C was used was reduced to about half that when the mold flux of Comparative Example F was used.

本発明は上記の例に限らず、各請求項に記載された技術的思想の範疇であれば、適宜実施の形態を変更しても良いことは言うまでもない。   The present invention is not limited to the above example, and it goes without saying that the embodiments may be changed as appropriate within the scope of the technical idea described in each claim.

1 鋳型
2 溶融金属
3 モールドパウダー
4 溶融スラグ
5 鋳片
6 フィルム
7 スラグリム
1 Mold 2 Molten Metal 3 Mold Powder 4 Molten Slag 5 Slab 6 Film 7 Slag Rim

Claims (2)

鋼等の高温溶融金属の連続鋳造に用いられ、第二族金属酸化物であるMgO ,CaO ,SrO,BaO とSiO2を主成分とし、これら主成分の合計濃度が60atomic%以上である鋼の連続鋳造用モールドパウダーであって、
前記主成分の合計濃度が60atomic%以上であるモールドパウダーの基材原料中に、第二族金属炭酸塩である炭酸マグネシウム、炭酸カルシウム、炭酸ストロンチウム、炭酸バリウムの内、少なくとも1種類以上を含有し、これら第二族金属炭酸塩が熱分解して生じる前記主成分となる第二族金属酸化物の合計濃度が7〜30atomic%の範囲内にあり、
かつ、前記基材原料中に含有したソーダ石灰ガラス粉に由来するSiO2が、モールドパウダーに含まれるSiO2の総量の50mass%以上を占めることを特徴とする鋼の連続鋳造用モールドパウダー。
It is used for continuous casting of high-temperature molten metals such as steel, and is mainly composed of group 2 metal oxides MgO, CaO, SrO, BaO and SiO 2 and the total concentration of these main components is 60 atomic% or more. Mold powder for continuous casting,
The base material of the mold powder in which the total concentration of the main components is 60 atomic% or more contains at least one of the group 2 metal carbonates magnesium carbonate, calcium carbonate, strontium carbonate, and barium carbonate. The total concentration of the Group 2 metal oxides, which are the main components generated by the thermal decomposition of these Group 2 metal carbonates, is in the range of 7 to 30 atomic%.
And the mold powder for continuous casting of steel, wherein SiO 2 derived from soda-lime glass powder contained in the base material occupies 50 mass% or more of the total amount of SiO 2 contained in the mold powder.
前記基材原料と、当該基材原料中に含有する第二族金属炭酸塩及びソーダ石灰ガラス粉の粒形状が顆粒であることを特徴とする請求項1に記載の鋼の連続鋳造用モールドパウダー。   The mold powder for continuous casting of steel according to claim 1, wherein the base material and the group shape metal carbonate and soda lime glass powder contained in the base material are granules. .
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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10501471A (en) * 1995-04-10 1998-02-10 フォセコ、インターナショナル、リミテッド Mold flux for continuous casting of steel
JP2010227972A (en) * 2009-03-27 2010-10-14 Shinagawa Refractories Co Ltd Mold powder for continuously casting steel

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10501471A (en) * 1995-04-10 1998-02-10 フォセコ、インターナショナル、リミテッド Mold flux for continuous casting of steel
JP2010227972A (en) * 2009-03-27 2010-10-14 Shinagawa Refractories Co Ltd Mold powder for continuously casting steel

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