JPH0741383B2 - Mold powder for continuous casting - Google Patents
Mold powder for continuous castingInfo
- Publication number
- JPH0741383B2 JPH0741383B2 JP5722291A JP5722291A JPH0741383B2 JP H0741383 B2 JPH0741383 B2 JP H0741383B2 JP 5722291 A JP5722291 A JP 5722291A JP 5722291 A JP5722291 A JP 5722291A JP H0741383 B2 JPH0741383 B2 JP H0741383B2
- Authority
- JP
- Japan
- Prior art keywords
- weight
- raw material
- powder
- carbon
- carbonate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 239000000843 powder Substances 0.000 title claims description 50
- 238000009749 continuous casting Methods 0.000 title claims description 14
- 239000002994 raw material Substances 0.000 claims description 47
- 238000002485 combustion reaction Methods 0.000 claims description 27
- 229910052799 carbon Inorganic materials 0.000 claims description 19
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 18
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 14
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 14
- 239000006229 carbon black Substances 0.000 claims description 14
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 claims description 10
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 claims description 10
- FGIUAXJPYTZDNR-UHFFFAOYSA-N potassium nitrate Chemical compound [K+].[O-][N+]([O-])=O FGIUAXJPYTZDNR-UHFFFAOYSA-N 0.000 claims description 10
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 claims description 10
- 229910000029 sodium carbonate Inorganic materials 0.000 claims description 7
- 238000002156 mixing Methods 0.000 claims description 6
- 239000000377 silicon dioxide Substances 0.000 claims description 6
- 239000011736 potassium bicarbonate Substances 0.000 claims description 5
- 229910000028 potassium bicarbonate Inorganic materials 0.000 claims description 5
- 235000015497 potassium bicarbonate Nutrition 0.000 claims description 5
- 229910000027 potassium carbonate Inorganic materials 0.000 claims description 5
- 235000011181 potassium carbonates Nutrition 0.000 claims description 5
- TYJJADVDDVDEDZ-UHFFFAOYSA-M potassium hydrogencarbonate Chemical compound [K+].OC([O-])=O TYJJADVDDVDEDZ-UHFFFAOYSA-M 0.000 claims description 5
- 229940086066 potassium hydrogencarbonate Drugs 0.000 claims description 5
- 235000010333 potassium nitrate Nutrition 0.000 claims description 5
- 239000004323 potassium nitrate Substances 0.000 claims description 5
- 229910000030 sodium bicarbonate Inorganic materials 0.000 claims description 5
- 235000017557 sodium bicarbonate Nutrition 0.000 claims description 5
- 235000017550 sodium carbonate Nutrition 0.000 claims description 5
- 235000010344 sodium nitrate Nutrition 0.000 claims description 5
- 239000004317 sodium nitrate Substances 0.000 claims description 5
- 239000000203 mixture Substances 0.000 claims description 4
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-N carbonic acid Chemical compound OC(O)=O BVKZGUZCCUSVTD-UHFFFAOYSA-N 0.000 claims 2
- 229910052744 lithium Inorganic materials 0.000 claims 2
- 238000013329 compounding Methods 0.000 claims 1
- 229910000831 Steel Inorganic materials 0.000 description 20
- 239000010959 steel Substances 0.000 description 20
- 239000002893 slag Substances 0.000 description 19
- 239000010410 layer Substances 0.000 description 9
- 239000000463 material Substances 0.000 description 9
- 229910001209 Low-carbon steel Inorganic materials 0.000 description 8
- 238000005255 carburizing Methods 0.000 description 8
- 238000006243 chemical reaction Methods 0.000 description 7
- 238000005469 granulation Methods 0.000 description 7
- 230000003179 granulation Effects 0.000 description 7
- 229910052751 metal Inorganic materials 0.000 description 7
- 239000002184 metal Substances 0.000 description 7
- 238000002844 melting Methods 0.000 description 5
- 230000008018 melting Effects 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 238000000354 decomposition reaction Methods 0.000 description 4
- 238000005266 casting Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 description 3
- 229910052808 lithium carbonate Inorganic materials 0.000 description 3
- 239000011734 sodium Substances 0.000 description 3
- 229910004298 SiO 2 Inorganic materials 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 235000012241 calcium silicate Nutrition 0.000 description 2
- 229910052918 calcium silicate Inorganic materials 0.000 description 2
- 239000003575 carbonaceous material Substances 0.000 description 2
- 239000003610 charcoal Substances 0.000 description 2
- 238000001125 extrusion Methods 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 239000008187 granular material Substances 0.000 description 2
- 230000005484 gravity Effects 0.000 description 2
- 239000000155 melt Substances 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- 239000005909 Kieselgur Substances 0.000 description 1
- 239000011398 Portland cement Substances 0.000 description 1
- 239000004111 Potassium silicate Substances 0.000 description 1
- 239000004115 Sodium Silicate Substances 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- AYJRCSIUFZENHW-DEQYMQKBSA-L barium(2+);oxomethanediolate Chemical compound [Ba+2].[O-][14C]([O-])=O AYJRCSIUFZENHW-DEQYMQKBSA-L 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 229910021538 borax Inorganic materials 0.000 description 1
- 239000000378 calcium silicate Substances 0.000 description 1
- JHLNERQLKQQLRZ-UHFFFAOYSA-N calcium silicate Chemical compound [Ca+2].[Ca+2].[O-][Si]([O-])([O-])[O-] JHLNERQLKQQLRZ-UHFFFAOYSA-N 0.000 description 1
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 description 1
- 150000001721 carbon Chemical class 0.000 description 1
- 235000019241 carbon black Nutrition 0.000 description 1
- 125000005587 carbonate group Chemical group 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 229910001610 cryolite Inorganic materials 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 239000010433 feldspar Substances 0.000 description 1
- 150000002222 fluorine compounds Chemical class 0.000 description 1
- 239000010881 fly ash Substances 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- BHEPBYXIRTUNPN-UHFFFAOYSA-N hydridophosphorus(.) (triplet) Chemical compound [PH] BHEPBYXIRTUNPN-UHFFFAOYSA-N 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- ORUIBWPALBXDOA-UHFFFAOYSA-L magnesium fluoride Chemical compound [F-].[F-].[Mg+2] ORUIBWPALBXDOA-UHFFFAOYSA-L 0.000 description 1
- 229910001635 magnesium fluoride Inorganic materials 0.000 description 1
- 230000005499 meniscus Effects 0.000 description 1
- 150000001247 metal acetylides Chemical class 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000010451 perlite Substances 0.000 description 1
- 235000019362 perlite Nutrition 0.000 description 1
- NNHHDJVEYQHLHG-UHFFFAOYSA-N potassium silicate Chemical compound [K+].[K+].[O-][Si]([O-])=O NNHHDJVEYQHLHG-UHFFFAOYSA-N 0.000 description 1
- 229910052913 potassium silicate Inorganic materials 0.000 description 1
- 235000019353 potassium silicate Nutrition 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 1
- 229910052911 sodium silicate Inorganic materials 0.000 description 1
- 239000004328 sodium tetraborate Substances 0.000 description 1
- 235000010339 sodium tetraborate Nutrition 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 239000010456 wollastonite Substances 0.000 description 1
- 229910052882 wollastonite Inorganic materials 0.000 description 1
Landscapes
- Continuous Casting (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、鋼の連続鋳造用モール
ドパウダーに関し、特に、極低炭素鋼、ステンレス鋼の
連続鋳造時に浸炭の少ない連続鋳造用モールドパウダー
に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold powder for continuous casting of steel, and more particularly to a mold powder for continuous casting of extremely low carbon steel and stainless steel with less carburization.
【０００２】鋼の連続鋳造においては、モールド内にお
いてモールドパウダーが添加される。浸漬ノズルを介し
てモールド内に注入された溶鋼表面上に添加されたモー
ルドパウダーは、溶鋼からの受熱により溶鋼表面より溶
融スラグ層、未溶融の原パウダー層の層状構造を形成
し、種々の役割を果たしながら消費される。特に、モ
ールドと凝固シェルとの潤滑作用、溶鋼中から浮上す
る介在物の溶解、吸収作用、溶鋼の保温作用が重要な
役割である。In continuous casting of steel, mold powder is added in the mold. The mold powder added on the molten steel surface injected into the mold through the immersion nozzle forms a layered structure of molten slag layer and unmelted raw powder layer from the molten steel surface by receiving heat from the molten steel and plays various roles. Is consumed while fulfilling. In particular, the role of lubrication between the mold and the solidified shell, dissolution of inclusions floating from the molten steel, absorption, and heat retention of the molten steel play important roles.
【０００３】近年、鋼の連続鋳造の進歩は目覚ましく、
鋳片品質や操業安定度に大きく影響するモールドパウダ
ーに対する要求も一段と厳しいものがあり、モールドパ
ウダーは各種鋼成分、各種鋳造条件に適合するように品
質設計がなされている。上記の特性を確保するため、一
般的なモールドパウダーには、ポルトランドセメント、
黄リンスラグ、高炉スラグ、ウォラストナイト、ダイカ
ルシウムシリケート、合成珪酸カルシウムなどを主原料
として、必要に応じて塩基度や嵩比重などの粉体特性調
整のためシリカ質原料を加え、更に、蛍石、氷晶石、硼
砂、フッ化マグネシウムなどの弗化物、炭酸ナトリウ
ム、炭酸バリウムなどの炭酸塩といった軟化点、粘度等
の溶融特性調整材としてのフラックス原料、溶融速度調
整材としての炭素質原料などを混合した混合タイプや、
炭素質原料を除く成分の全部を予め溶融水砕したプリメ
ルトタイプ、一部を予め溶融水砕したセミプリメルトタ
イプがある。また、一部金属や合金原料を使用したタイ
プもある。更に、形状的には、粉末原料を混合した粉末
タイプと更に種々の方法で造粒した顆粒タイプがある。In recent years, the progress of continuous casting of steel has been remarkable,
There are even more stringent requirements for mold powders, which greatly affect the quality of slabs and the stability of operation, and the quality of mold powders is designed to meet various steel components and various casting conditions. To ensure the above characteristics, general mold powders include Portland cement,
Yellow phosphorous slag, blast furnace slag, wollastonite, dicalcium silicate, synthetic calcium silicate, etc. as the main raw materials, and if necessary, siliceous raw materials are added to adjust powder characteristics such as basicity and bulk specific gravity. , Cryolite, borax, fluorides such as magnesium fluoride, carbonates such as sodium carbonate and barium carbonate, softening point, flux raw materials for adjusting melting characteristics such as viscosity, carbonaceous raw materials for melting speed adjusting materials, etc. Mixed type that mixed
There are a pre-melt type in which all the components except the carbonaceous raw material are previously melt-water granulated, and a semi-pre-melt type in which a part of them are previously melt-water granulated. In addition, Thailand using some metal and alloy raw materials
There is also a pu. Further, in terms of shape, there are a powder type in which powder raw materials are mixed and a granule type in which granulation is performed by various methods.
【０００４】近年、自動車用を中心として需要が急増し
ている極低炭素鋼の連続鋳造において、モールドパウダ
ーは溶鋼の保温作用に優れるだけでなく、パウダー中の
炭素質原料に起因する溶鋼の浸炭を生じさせないことが
極めて重要になってきている。In continuous casting of ultra-low carbon steel, which has been rapidly increasing in demand mainly for automobiles in recent years, the mold powder not only excels in heat retaining effect of molten steel, but also carburizes molten steel due to carbonaceous raw material in the powder. It is becoming extremely important not to cause
【０００５】パウダー中の炭素質原料に起因する溶鋼の
浸炭を防止する方法としては、パウダー中のカーボン質
原料の使用量を極力抑えるとの発想から、代替の溶融速
度調整材としてＳｉ3Ｎ4、ＴｉＮ、ＳｉＣなどの窒化
物、炭化物または金属などが提案され、また、２ＣａＯ
・ＳｉＯ2を用いる方法も提案されている。これらの溶
融速度調整材を併用することによりカーボン質原料の使
用量の少ない極低炭素鋼用モールドパウダーが開示され
ている。As a method of preventing carburization of molten steel due to the carbonaceous raw material in the powder, Si 3 N 4 is used as an alternative melting rate adjusting material from the idea of suppressing the use amount of the carbonaceous raw material in the powder as much as possible. , TiN, SiC and other nitrides, carbides or metals have been proposed, and 2CaO
-A method using SiO 2 has also been proposed. A mold powder for ultra-low carbon steel in which the amount of carbonaceous raw material used is small is disclosed by using these melting rate adjusting materials together.
【０００６】[0006]
【発明が解決しようとする課題】上記の炭素質原料の使
用量の少ない極低炭素鋼用モールドパウダーは、浸炭の
低減にはある程度の効果はあるものの、保温性の低下や
滓化不良等の問題を引き起こし、実用的とは言い難い。
なぜなら、カーボン質原料は滓化溶融速度調整材として
の役割を果たすだけでなく、未溶融の原パウダー層内に
おいては、種々の原料相互の焼結抑制材として寄与し、
低熱伝導の層を維持するとともに、酸化時の発熱反応に
より溶鋼の保温性に果たす役割大であり、上記のモール
ドパウダーは、これらの役割を十分果たせないためであ
る。Although the above-mentioned mold powder for ultra-low carbon steel, which uses a small amount of carbonaceous raw material, has some effect in reducing carburization, it does not cause deterioration in heat retention and poor slag formation. It causes problems and is hardly practical.
This is because the carbonaceous raw material not only plays a role of a slag melting rate adjusting material, but also contributes as a sintering suppressing material for various raw materials in the unmelted raw powder layer,
This is because the role of maintaining the low thermal conductivity layer and the heat retaining property of the molten steel due to the exothermic reaction during oxidation are large, and the above-mentioned mold powder cannot sufficiently fulfill these roles.
【０００７】また、浸炭についても、モールド内の湯面
変動が大きい場合、原パウダー層と溶鋼との接触により
起こる浸炭の低減についてはカーボン質原料の使用量が
少ないことが接触機会の減少につながるため効果を挙げ
ていたが、湯面制御技術が進歩した現在では、この湯面
変動起因の浸炭は余り大きな問題ではなく、湯面の安定
した定常鋳造時に起こる浸炭の低減が特に重要である。
すなわち、炭素質原料使用量低減だけでは、浸炭の根本
的な解決にはなっていないのが現状である。Also, regarding carburization, when the fluctuation of the molten metal surface in the mold is large, in order to reduce the carburization caused by the contact between the raw powder layer and the molten steel, the use amount of the carbonaceous raw material is small, which leads to a decrease in contact opportunities. However, the carburization caused by the fluctuation of the molten metal level is not a big problem at present, and the reduction of the carburizing that occurs during stable steady casting of the molten metal level is particularly important.
In other words, the current situation is that reducing the amount of carbonaceous raw material used is not a fundamental solution to carburization.
【０００８】極低炭素鋼用モールドパウダーとしては、
浸炭を起こさず、かつ保温性、滓化性状に優れることが
必要不可欠であり、実用的な完成品はないのが現状であ
る。As a mold powder for ultra-low carbon steel,
It is indispensable that it does not cause carburization, and has excellent heat retention and slag formation properties, and there is no practical finished product at present.
【０００９】[0009]
【課題を解決するための手段】本発明者らは、上記課題
を解決するために種々検討を重ねた結果、浸炭のメカニ
ズムを明らかにし、上述のごとき従来の極低炭素鋼用モ
ールドパウダーの欠点をすべて克服できることを見出し
た。As a result of various studies to solve the above problems, the present inventors have clarified the mechanism of carburization, and have the drawbacks of the conventional mold powder for ultra-low carbon steel as described above. I found that I can overcome all.
【００１０】本発明に係る連続鋳造用モールドパウダー
は、比表面積９５ＢＥＴ−ｍ2／ｇ以上で、かつｐＨ８
未満のカーボンブラック６０重量％以上を含むカーボン
質原料を０.５〜５重量％、カーボンの燃焼促進剤とし
て炭酸ナトリウム、炭酸水素ナトリウム、硝酸ナトリウ
ム、炭酸カリウム、炭酸水素カリウム、硝酸カリウム、
炭酸リチウムの１種または２種以上を３〜３５重量％含
有し、燃焼促進剤とカーボン質原料の配合比が重量比で
５.０以上であることを特徴とする。The mold powder for continuous casting according to the present invention has a specific surface area of 95 BET-m 2 / g or more and a pH of 8.
Less than 0.5% by weight of a carbonaceous raw material containing 60% by weight or more of carbon black, and sodium carbonate, sodium hydrogencarbonate, sodium nitrate, potassium carbonate, potassium hydrogencarbonate, potassium nitrate as a carbon combustion accelerator.
One or two or more kinds of lithium carbonate is contained in an amount of 3 to 35% by weight, and the blending ratio of the combustion promoter and the carbonaceous raw material is 5.0 or more by weight.
【００１１】また、本発明の他の実施態様に係る連続鋳
造用モールドパウダーは、比表面積９５ＢＥＴ−ｍ2／
ｇ以上で、かつｐＨ８未満のカーボンブラック６０重量
％以上を含むカーボン質原料を０.５〜５重量％、カー
ボンの燃焼促進剤として炭酸ナトリウム、炭酸水素ナト
リウム、硝酸ナトリウム、炭酸カリウム、炭酸水素カリ
ウム、硝酸カリウム、炭酸リチウムの１種または２種以
上を３〜３５重量％並びにシリカ含有量６０重量％以上
のシリカ質原料を１０重量％未満含有し、燃焼促進剤と
シリカ質原料の配合比が重量比で１.５以上、燃焼促進
剤とカーボン質原料の配合比が重量比で５.０以上であ
ることを特徴とする。Further, a mold powder for continuous casting according to another embodiment of the present invention has a specific surface area of 95 BET-m 2 /
0.5 to 5% by weight of a carbonaceous raw material containing 60% by weight or more of carbon black having a pH of 8 or less and a pH of less than 8, sodium carbonate, sodium hydrogen carbonate, sodium nitrate, potassium carbonate, potassium hydrogen carbonate as a carbon combustion accelerator. , Potassium nitrate, lithium carbonate, 3 to 35% by weight, and less than 10% by weight of a siliceous raw material having a silica content of 60% by weight or more, and the mixing ratio of the combustion accelerator and the siliceous raw material is weight. The ratio is 1.5 or more, and the mixing ratio of the combustion promoter and the carbonaceous raw material is 5.0 or more by weight.
【００１２】[0012]
【作用】本発明者等は種々の研究、検討を行った結果、
以下の知見を得た：実際の鋳片の浸炭状況を調べる
と、浸炭は極表層部(〜２ｍｍ)で著しい。従って、従来
から言われているように、モールド内全面で浸炭が進ん
でいるのではなく、浸炭は主としてメニスカス近傍で起
こっていると考えられる；浸炭のメカニズムを明らか
にするために、溶融パウダースラグ層、スラグフィルム
中のカーボンの挙動を検討した結果、従来カーボンがな
いとされていた溶融パウダースラグ層、スラグフィルム
内にも２００〜９００ｐｐｍ程度のカーボンが存在する
ことが判明した；極低炭素鋼と実機でサンプリングし
たパウダースラグ、スラグフィルムとを接触させて加熱
すると、パウダースラグ、スラグフィルム中のカーボン
量が極僅かにも拘わらず浸炭が起こる；従って、モー
ルドパウダーがモールド内で溶融するときに、カーボン
質原料が溶融パウダースラグ層中に残存し、このカーボ
ンがメニスカス近傍で溶鋼や鋼の初期凝固シェルと接触
して浸炭が起こると考えられる；各種カーボン質原料
の極低炭素鋼への浸炭速度を調査検討した結果、木炭及
びカーボンブラックが最も遅いことが判明した。[Function] As a result of various studies and investigations by the present inventors,
The following findings were obtained: When the actual carburizing condition of the cast slab was examined, carburizing was remarkable at the extreme surface layer portion (~ 2 mm). Therefore, it is considered that carburization does not proceed on the entire surface of the mold as it has been conventionally said, but carburization mainly occurs near the meniscus; in order to clarify the mechanism of carburization, molten powder slag is used. As a result of investigating the behavior of carbon in the layer and the slag film, it was found that about 200 to 900 ppm of carbon is also present in the molten powder slag layer and the slag film, which were conventionally considered to have no carbon; And heating the powder slag and slag film sampled with an actual machine in contact with each other causes carburization to occur even though the amount of carbon in the powder slag and slag film is extremely small; therefore, when the mold powder melts in the mold. , The carbonaceous raw material remains in the molten powder slag layer, and this carbon It is considered that carburization occurs in the vicinity of the molten steel and in contact with the initially solidified shell of steel; carburization rate of ultra-low carbon steel of various carbonaceous raw materials is investigated and found to be the slowest for charcoal and carbon black did.
【００１３】すなわち、湯面の安定した定常鋳造時に起
こる浸炭は、このパウダースラグやスラグフィルムを介
して起こることが明らかとなった。浸炭を根本的に解決
するためには、この浸炭を防止する必要がある。そのた
めには、モールド内でパウダーが溶融する際に、カーボ
ン質原料を完全燃焼させてパウダースラグやスラグフィ
ルム中にカーボンを残さないこと、また、残存しても溶
鋼や鋼の初期凝固シェルと接触したときの浸炭の速度が
遅いことが極めて重要である。That is, it has been clarified that the carburization which occurs during stable steady casting of the molten metal surface occurs through the powder slag and the slag film. In order to solve the carburization fundamentally, it is necessary to prevent the carburization. To that end, when the powder melts in the mold, the carbonaceous raw material must be completely burned to leave no carbon in the powder slag or slag film, and even if it remains, it must come into contact with the molten steel or the initially solidified shell of steel. It is extremely important that the carburizing speed is slow.
【００１４】本発明の連続鋳造用モールドパウダーは上
記の知見を基になされたものである。すなわち、カーボ
ン質原料として比表面積９５ＢＥＴ−ｍ2／ｇ以上で、
かつｐＨ８未満のカーボンブラックを使用し、完全燃焼
させるために燃焼促進剤を用いる。カーボンブラックの
選定理由は鋼への浸炭速度が遅いためであり、カーボン
ブラックとしては反応性に富み、分散性に優れる比表面
積９５ＢＥＴ−ｍ2／ｇ以上で、かつｐＨ８未満のカー
ボンブラックの使用が望ましい。比表面積９５ＢＥＴ−
ｍ2／ｇ未満だと、反応性が不十分で、完全燃焼が難し
く好ましくない。また、ｐＨ８以上では分散性が不十分
で凝集物を残し易く、完全燃焼の障害となり易く好まし
くない。ただし、カーボン質原料として比表面積９５Ｂ
ＥＴ−ｍ2／ｇ以上で、かつｐＨ８未満のカーボンブラ
ックを６０重量％以上用いれば、４０重量％未満の範囲
で他のカーボンブラック及び木炭も使用可能である。カ
ーボン質原料の使用量としては０.５〜５重量％が望ま
しい。該使用量が０.５重量％未満であれば、滓化速度
の調整が困難となり、また、５重量％を超えると完全燃
焼が難しく好ましくない。The mold powder for continuous casting of the present invention is based on the above findings. That is, as a carbonaceous raw material, with a specific surface area of 95 BET-m 2 / g or more,
A carbon black having a pH of less than 8 is used, and a combustion accelerator is used for complete combustion. The reason for selecting carbon black is that the carburizing speed into steel is slow, and it is recommended to use carbon black having a specific surface area of 95 BET-m 2 / g or more and a pH of less than 8 which is highly reactive and excellent in dispersibility as carbon black. desirable. Specific surface area 95 BET-
If it is less than m 2 / g, reactivity is insufficient and complete combustion is difficult, which is not preferable. Further, when the pH is 8 or more, the dispersibility is insufficient and aggregates are liable to be left, which hinders complete combustion, which is not preferable. However, the carbonaceous raw material has a specific surface area of 95B.
If 60% by weight or more of carbon black having an ET-m 2 / g or more and a pH of less than 8 is used, other carbon black and charcoal can be used within the range of less than 40% by weight. The amount of carbonaceous material used is preferably 0.5 to 5% by weight. If the amount used is less than 0.5% by weight, it will be difficult to adjust the slagging rate, and if it exceeds 5% by weight, complete combustion will be difficult, which is not preferable.
【００１５】カーボンの燃焼促進剤として炭酸ナトリウ
ム、炭酸水素ナトリウム、硝酸ナトリウム、炭酸カリウ
ム、炭酸水素カリウム、硝酸カリウム、炭酸リチウムの
１種または２種以上を使用することによりカーボンを安
定に、かつ完全燃焼させることができる。炭酸ナトリウ
ムを例にとると下記の反応が進行し、カーボンの酸化燃
焼が促進される：Stable and complete combustion of carbon by using one or more of sodium carbonate, sodium hydrogen carbonate, sodium nitrate, potassium carbonate, potassium hydrogen carbonate, potassium nitrate, lithium carbonate as a carbon combustion accelerator. Can be made. Taking sodium carbonate as an example, the following reactions proceed to promote the oxidative combustion of carbon:
【００１６】[0016]
【化１】 Ｎａ2ＣＯ3＋２Ｃ→２Ｎａ↑＋３ＣＯ・・・・・(1)[Chemical formula 1] Na 2 CO 3 + 2C → 2Na ↑ + 3CO (1)
【００１７】更に、(1)式で生じたＮａガスが未溶融の
原パウダー層中の酸素と反応して酸化燃焼する。このた
め発熱反応熱が得られるのに加え、炭酸塩の分解に伴う
吸熱反応が起こらないため溶鋼の保温性の点からも極め
て有効である。炭酸塩の使用が保温性の低下につながら
ないのである。Further, the Na gas generated by the formula (1) reacts with oxygen in the unmelted raw powder layer to oxidize and burn. Therefore, in addition to obtaining exothermic reaction heat, an endothermic reaction due to decomposition of carbonate does not occur, which is extremely effective from the viewpoint of heat retention of molten steel. The use of carbonate does not reduce the heat retention.
【００１８】燃焼促進剤の使用量は３〜３５重量％が望
ましい。３重量％未満では効果がなく、３５重量％を超
えるとガス発生量が多くなりすぎ、作業性が低下するた
め好ましくない。更に、燃焼促進剤とカーボン質原料の
配合比が重量比で５.０以上であることが重要である。
この重量比が５.０未満であると、カーボンの燃焼が十
分進まず、未燃焼のカーボンが残り易く好ましくない。The amount of the combustion accelerator used is preferably 3 to 35% by weight. If it is less than 3% by weight, there is no effect, and if it exceeds 35% by weight, the amount of gas generated is too large and the workability is deteriorated. Further, it is important that the blending ratio of the combustion accelerator and the carbonaceous raw material is 5.0 or more by weight.
If this weight ratio is less than 5.0, the combustion of carbon does not proceed sufficiently and unburned carbon tends to remain, which is not preferable.
【００１９】更に、モールドパウダーの塩基度や嵩比重
などの粉体特性調整のために使用されるシリカ質原料と
の関係も重要である。例えば製鉄研究第２９９号(１９
７０年)第５２〜６０頁に記載されているように、Ｓｉ
Ｏ2がＮａ2ＣＯ3の分解を促進することが知られてい
る。そこで、カーボンと燃焼促進剤の反応に及ぼすシリ
カ質原料の影響について調査した。その結果、ＳｉＯ2
が多量に存在すると、カーボンと燃焼促進剤の反応が円
滑に進まず、燃焼促進剤の分解が優先的に進んでしまう
ため好ましくない。シリカ質原料を添加配合する場合に
は、シリカ含有量６０重量％以上のシリカ質原料を１０
重量％未満に限定する必要がある。シリカ質原料として
はパーライト、フライアッシュ、珪砂、長石、珪石、珪
藻土、珪酸ナトリウム、珪酸カリウム、ガラス粉など通
常モールドパウダーに使用される原料が使用できる。な
お、燃焼促進剤とシリカ質原料の配合比が重量比で１.
５以上であることが重要である。この重量比が１.５未
満であると、燃焼促進剤のシリカによる分解が優先的に
進み易く、燃焼促進剤とカーボンとの反応が不充分とな
り、未燃焼のカーボンが残り易く好ましくない。Further, the relationship with the siliceous raw material used for adjusting the powder characteristics such as basicity and bulk specific gravity of the mold powder is also important. For example, Ironmaking Research No. 299 (19
70), as described on pages 52-60, Si
O 2 is known to accelerate the decomposition of Na 2 CO 3 . Therefore, the influence of the siliceous raw material on the reaction between carbon and the combustion accelerator was investigated. As a result, SiO 2
Is present in a large amount, the reaction between the carbon and the combustion accelerator does not proceed smoothly, and the decomposition of the combustion accelerator proceeds preferentially, which is not preferable. When a siliceous raw material is added and blended, the siliceous raw material having a silica content of 60% by weight or more is used.
It should be limited to less than wt%. As the siliceous raw material, there can be used raw materials usually used for mold powders such as perlite, fly ash, silica sand, feldspar, silica stone, diatomaceous earth, sodium silicate, potassium silicate and glass powder. The weight ratio of the combustion accelerator and the siliceous raw material is 1.
It is important that it is 5 or more. If this weight ratio is less than 1.5, the decomposition of the combustion promoter by silica tends to proceed preferentially, the reaction between the combustion promoter and carbon becomes insufficient, and unburned carbon remains, which is not preferable.
【００２０】なお、本発明の連続鋳造用モールドパウダ
ーは主原料（基材原料）、シリカ質原料、フラックス原
料、燃焼促進剤、カーボン質原料、その他の原料（酸化
物、金属、合金）など前述の粉末原料を混合した粉末状
または押出造粒、撹拌造粒、流動造粒、転動造粒、噴霧
造粒などの方法で造粒した顆粒状にて使用することがで
きる。造粒に際しては、必要に応じて有機質、無機質の
バインダーを使用することができる。The mold powder for continuous casting of the present invention comprises a main raw material (base material raw material), a siliceous raw material, and a flux raw material.
Materials, combustion accelerators, carbonaceous materials, other materials (oxidation
(Materials, metals, alloys) mixed with the above powder raw materials or in the form of granules granulated by a method such as extrusion granulation, stirring granulation, fluidized granulation, tumbling granulation, spray granulation, etc. be able to. At the time of granulation, an organic or inorganic binder can be used if necessary.
【００２１】[0021]
【実施例】以下に実施例を挙げて本発明の連続鋳造用モ
ールドパウダーを更に説明する。 実施例 以下の表１に本発明品及び比較品の配合及び実機での使
用結果を記載する。表１中、本発明品Ｎo.４は粉末原料
混合物を加水混練し、押出造粒機によって柱状に造粒し
た顆粒品であり、その他は粉末配合物をＶ型ミキサーに
て混合した粉末品である。EXAMPLES The mold powder for continuous casting of the present invention will be further described below with reference to examples. Examples Table 1 below shows the formulations of the products of the present invention and comparative products, and the results of use in actual machines. In Table 1, the product No. 4 of the present invention is a granulated product in which the powder raw material mixture is hydro-kneaded and granulated into a column shape by an extrusion granulator, and the others are powder products obtained by mixing the powder blend with a V-type mixer. is there.
【００２２】[0022]
【表１】 [Table 1]
【００２３】[0023]
【表２】 [Table 2]
【００２４】表１中、カーボンブラックＡは比表面積１
０５ＢＥＴ−ｍ2／ｇ、ｐＨ＝６のものであり、カーボ
ンブラックＢは比表面積１３０ＢＥＴ−ｍ2／ｇ、ｐＨ
＝３のものであり、カーボンブラックＣは比表面積８５
ＢＥＴ−ｍ2／ｇ、ｐＨ＝８のものである。比表面積はB
runauer−Emmett−Teller法にて測定した値である。In Table 1, carbon black A has a specific surface area of 1
05BET-m 2 / g, pH = 6, carbon black B has a specific surface area of 130 BET-m 2 / g, pH
= 3, carbon black C has a specific surface area of 85
BET-m 2 / g, pH = 8. Specific surface area is B
It is a value measured by the runauer-Emmett-Teller method.
【００２５】[0025]
【発明の効果】以上のごとく、本発明の連続鋳造用モー
ルドパウダーは、浸炭低減対策である炭素質原料の使用
量低減だけでは解決できなかった浸炭の問題に対し、浸
炭機構を明らかにし、根本的な解決を実現したものであ
り、極低炭素鋼やステンレス鋼等用のモールドパウダー
として有効である。As described above, the mold powder for continuous casting of the present invention clarifies the carburizing mechanism for the problem of carburizing which cannot be solved only by reducing the amount of carbonaceous raw material used as a carburizing reducing measure. It is an effective solution as a mold powder for ultra-low carbon steel and stainless steel.
Claims (2)
かつｐＨ８未満のカーボンブラック６０重量％以上を含
むカーボン質原料を０.５〜５重量％、カーボンの燃焼
促進剤として炭酸ナトリウム、炭酸水素ナトリウム、硝
酸ナトリウム、炭酸カリウム、炭酸水素カリウム、硝酸
カリウム、炭酸リチウムの１種または２種以上を３〜３
５重量％含有し、燃焼促進剤とカーボン質原料の配合比
が重量比で５.０以上であることを特徴とする連続鋳造
用モールドパウダー。1. A specific surface area of 95 BET-m 2 / g or more,
And 0.5 to 5% by weight of a carbonaceous raw material containing 60% by weight or more of carbon black having a pH of less than 8, sodium carbonate, sodium hydrogen carbonate, sodium nitrate, potassium carbonate, potassium hydrogen carbonate, potassium nitrate, carbonic acid as a combustion promoter of carbon. 3 to 3 of one kind or two or more kinds of lithium
A mold powder for continuous casting, containing 5% by weight, and the mixture ratio of the combustion accelerator and the carbonaceous raw material is 5.0 or more by weight.
かつｐＨ８未満のカーボンブラック６０重量％以上を含
むカーボン質原料を０.５〜５重量％、カーボンの燃焼
促進剤として炭酸ナトリウム、炭酸水素ナトリウム、硝
酸ナトリウム、炭酸カリウム、炭酸水素カリウム、硝酸
カリウム、炭酸リチウムの１種または２種以上を３〜３
５重量％並びにシリカ含有量６０重量％以上のシリカ質
原料を１０重量％未満含有し、燃焼促進剤とシリカ質原
料の配合比が重量比で１.５以上、燃焼促進剤とカーボ
ン質原料の配合比が重量比で５.０以上であることを特
徴とする連続鋳造用モールドパウダー。2. A specific surface area of 95 BET-m 2 / g or more,
And 0.5 to 5% by weight of a carbonaceous raw material containing 60% by weight or more of carbon black having a pH of less than 8, sodium carbonate, sodium hydrogen carbonate, sodium nitrate, potassium carbonate, potassium hydrogen carbonate, potassium nitrate, carbonic acid as a combustion promoter of carbon. 3 to 3 of one kind or two or more kinds of lithium
5% by weight and less than 10% by weight of a siliceous raw material having a silica content of 60% by weight or more, and the mixing ratio of the combustion accelerator and the siliceous raw material is 1.5 or more by weight. Mold powder for continuous casting, characterized in that the compounding ratio is 5.0 or more by weight.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5722291A JPH0741383B2 (en) | 1991-03-20 | 1991-03-20 | Mold powder for continuous casting |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5722291A JPH0741383B2 (en) | 1991-03-20 | 1991-03-20 | Mold powder for continuous casting |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04294849A JPH04294849A (en) | 1992-10-19 |
| JPH0741383B2 true JPH0741383B2 (en) | 1995-05-10 |
Family
ID=13049505
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5722291A Expired - Fee Related JPH0741383B2 (en) | 1991-03-20 | 1991-03-20 | Mold powder for continuous casting |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0741383B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06198404A (en) * | 1993-01-07 | 1994-07-19 | Nippon Steel Corp | Hollow ceramic particle for heat insulation of molten steel and its production |
| JP4508086B2 (en) * | 2005-11-14 | 2010-07-21 | 住友金属工業株式会社 | Mold powder for continuous casting of steel and continuous casting method |
| CN107282903B (en) * | 2016-12-30 | 2019-04-05 | 西峡龙成冶金材料有限公司 | A kind of continuous super low carbon steel casting crystallizer protecting residue |
| CN114769533B (en) * | 2022-03-31 | 2024-08-20 | 西峡县西保冶金材料有限公司 | Functional protection material of continuous casting crystallizer for industrial pure iron |
-
1991
- 1991-03-20 JP JP5722291A patent/JPH0741383B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04294849A (en) | 1992-10-19 |
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