JP2002129223A - Processing method and slab of molten steel for high carbon steel - Google Patents
Processing method and slab of molten steel for high carbon steelInfo
- Publication number
- JP2002129223A JP2002129223A JP2000324161A JP2000324161A JP2002129223A JP 2002129223 A JP2002129223 A JP 2002129223A JP 2000324161 A JP2000324161 A JP 2000324161A JP 2000324161 A JP2000324161 A JP 2000324161A JP 2002129223 A JP2002129223 A JP 2002129223A
- Authority
- JP
- Japan
- Prior art keywords
- molten steel
- steel
- weight
- slab
- added
- 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.)
- Granted
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 144
- 239000010959 steel Substances 0.000 title claims abstract description 144
- 229910000677 High-carbon steel Inorganic materials 0.000 title claims abstract description 23
- 238000003672 processing method Methods 0.000 title description 2
- 238000000034 method Methods 0.000 claims abstract description 31
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 8
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 7
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 claims abstract description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 22
- 229910052760 oxygen Inorganic materials 0.000 claims description 22
- 239000001301 oxygen Substances 0.000 claims description 22
- 229910052749 magnesium Inorganic materials 0.000 claims description 18
- 238000007711 solidification Methods 0.000 abstract description 16
- 230000008023 solidification Effects 0.000 abstract description 16
- 230000007547 defect Effects 0.000 abstract description 15
- 238000011081 inoculation Methods 0.000 abstract description 15
- 239000000463 material Substances 0.000 abstract description 14
- 150000003568 thioethers Chemical class 0.000 abstract description 2
- 239000011777 magnesium Substances 0.000 description 62
- 229910052751 metal Inorganic materials 0.000 description 13
- 239000002184 metal Substances 0.000 description 13
- 239000013078 crystal Substances 0.000 description 12
- 238000005204 segregation Methods 0.000 description 10
- 238000005266 casting Methods 0.000 description 9
- 229910052726 zirconium Inorganic materials 0.000 description 9
- 239000002054 inoculum Substances 0.000 description 8
- 229910001093 Zr alloy Inorganic materials 0.000 description 6
- 238000011156 evaluation Methods 0.000 description 6
- 229910001566 austenite Inorganic materials 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 5
- 238000007654 immersion Methods 0.000 description 5
- 238000003756 stirring Methods 0.000 description 5
- 238000001816 cooling Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 238000009749 continuous casting Methods 0.000 description 3
- 238000005096 rolling process Methods 0.000 description 3
- 229910052717 sulfur Inorganic materials 0.000 description 3
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 2
- 229910017076 Fe Zr Inorganic materials 0.000 description 2
- 229910000861 Mg alloy Inorganic materials 0.000 description 2
- 229910018505 Ni—Mg Inorganic materials 0.000 description 2
- 229910007981 Si-Mg Inorganic materials 0.000 description 2
- 229910008316 Si—Mg Inorganic materials 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000007664 blowing Methods 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 239000002893 slag Substances 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 229910001018 Cast iron Inorganic materials 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000015271 coagulation Effects 0.000 description 1
- 238000005345 coagulation Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- VASIZKWUTCETSD-UHFFFAOYSA-N manganese(II) oxide Inorganic materials [Mn]=O VASIZKWUTCETSD-UHFFFAOYSA-N 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- OXNIZHLAWKMVMX-UHFFFAOYSA-N picric acid Chemical compound OC1=C([N+]([O-])=O)C=C([N+]([O-])=O)C=C1[N+]([O-])=O OXNIZHLAWKMVMX-UHFFFAOYSA-N 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- VSZWPYCFIRKVQL-UHFFFAOYSA-N selanylidenegallium;selenium Chemical compound [Se].[Se]=[Ga].[Se]=[Ga] VSZWPYCFIRKVQL-UHFFFAOYSA-N 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Landscapes
- Continuous Casting (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
(57)【要約】
【課題】 溶鋼中に、接種核として有効な酸化物や硫化
物を生成させ、凝固した鋳片の凝固組織を微細にして内
部欠陥等の発生を防止し、この鋳片を加工した鋼材の品
質を向上することができる高炭素鋼用溶鋼の処理方法及
び鋳片を提供する。
【解決手段】 炭素を０．５重量％以上含有する高炭素
鋼用溶鋼の処理方法において、溶鋼１１中にＺｒを添加
してＺｒ酸化物を生成させた後、溶鋼１１にＭｇを添加
してＭｇ硫化物を生成させる。
(57) [Summary] [PROBLEMS] To produce oxides and sulfides effective as inoculation nuclei in molten steel, to refine the solidification structure of the solidified slab to prevent the occurrence of internal defects, etc. Provided are a method for treating molten steel for high carbon steel and a slab that can improve the quality of a steel material obtained by processing steel. SOLUTION: In a method of treating molten steel for high carbon steel containing 0.5% by weight or more of carbon, Zr is added to molten steel 11 to generate a Zr oxide, and then Mg is added to molten steel 11. Generate Mg sulfide.
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、溶鋼の凝固組織を
微細にして鋳片の品質を向上することができる高炭素鋼
用溶鋼の処理方法及び鋳片に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a method for treating molten steel for high carbon steel, which can improve the quality of the slab by making the solidification structure of the molten steel fine.
【０００２】[0002]
【従来の技術】従来、溶鋼を凝固させた鋳片には、中心
偏析やセンターポロシティ、内部割れ等の内部欠陥が発
生する場合がある。この内部欠陥を抑制するため、鋳造
時の溶鋼の温度を低くする低温鋳造を行ったり、鋳型や
支持セグメントに電磁攪拌装置を設置して凝固しつつあ
る溶鋼を攪拌する等により、溶鋼が凝固した鋳片の等軸
晶の形成を促進し、凝固組織を微細化することが行われ
ている。しかし、低温鋳造を行うと、溶鋼を鋳型に注湯
する浸漬ノズルの詰まりが生じる。その結果、溶鋼湯面
や鋳造速度が変動して操業が不安定になり、場合によっ
ては鋳造作業の中断を招く。一方、電磁攪拌装置を用い
て溶鋼を攪拌する場合は、攪拌力を付与した近傍の溶鋼
の凝固組織を微細にできるが、鋳片の全体に攪拌力を付
与できないため、全体を等軸晶の微細な凝固組織にする
ことができない。しかも、鋳片の全体を等軸晶にするに
は、電磁攪拌装置を多段に配置する必要があり、設備費
用や電力コストが増大したり、設備制約から設置するこ
とが困難となる。この対策として、特開平７−６２４１
７号公報に記載されているように、金属ＭｇやＭｇ合金
に、Ｓｉ、Ｍｎ、Ａｌ、Ｃの一種以上を混合して溶鋼に
添加し、生成する酸化物のサイズを小さくし、しかも、
Ｍｇの添加コストを低減することが行われている。更
に、特開平９−２８７０１５号公報に記載されているよ
うに、溶鋼に、金属ＡｌあるいはＡｌ合金を添加してＡ
ｌ脱酸処理を行った後に、Ｚｒ、Ｃａ、Ｍｇの一種以上
を添加して脱酸を行い、溶鋼中の粗大なアルミナクラス
ター（酸化物）の個数を低減して製品の表面品質を改善
することが行われている。2. Description of the Related Art Heretofore, cast iron obtained by solidifying molten steel sometimes has internal defects such as center segregation, center porosity and internal cracks. In order to suppress this internal defect, the molten steel was solidified by performing low-temperature casting to lower the temperature of the molten steel at the time of casting, or by installing an electromagnetic stirrer in the mold or the support segment to stir the solidifying molten steel. 2. Description of the Related Art The formation of equiaxed crystals in cast slabs has been promoted and the solidification structure has been refined. However, when low-temperature casting is performed, clogging of the immersion nozzle for pouring molten steel into the mold occurs. As a result, the molten steel surface and the casting speed fluctuate and the operation becomes unstable, and in some cases, the casting operation is interrupted. On the other hand, when stirring the molten steel using an electromagnetic stirrer, the solidification structure of the molten steel in the vicinity of the applied stirring power can be fine, but the stirring power cannot be applied to the entire cast slab, so that the whole is equiaxed. It cannot be a fine solidified structure. In addition, in order to make the entire cast slab equiaxed, it is necessary to arrange electromagnetic stirring devices in multiple stages, which increases equipment costs and electric power costs, and makes it difficult to install them due to equipment restrictions. As a countermeasure against this, Japanese Patent Laid-Open No. 7-6241
As described in Japanese Patent Publication No. 7, a metal Mg or Mg alloy is mixed with at least one of Si, Mn, Al, and C and added to molten steel to reduce the size of the generated oxide.
The cost of adding Mg has been reduced. Further, as described in Japanese Patent Application Laid-Open No. 9-287015, metal Al or Al alloy is added to
1 After deoxidation, one or more of Zr, Ca and Mg are added to perform deoxidation, and the number of coarse alumina clusters (oxides) in the molten steel is reduced to improve the surface quality of the product. That is being done.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、特開平
７−６２４１７号公報に記載された方法では、Ｍｇを添
加した際に、ＳｉＯ2 、ＭｎＯ、Ａｌ2 Ｏ3 等の酸化物
が同時に生成して、酸化物の量が増加し、この酸化物が
脱酸過程で生成したＭｇＯと結合して低融点の酸化物を
形成し、溶鋼の凝固時に接種核として作用しなくなる。
しかも、凝固時の初晶がオーステナイト組織である溶鋼
に対して、接種核として作用する酸化物を優先的に生成
させることができない。しかも、この溶鋼を凝固させた
鋳片は、凝固組織が粗大化しており、中心偏析やセンタ
ーポロシティ、内部割れ等の内部欠陥が発生し、鋳片の
品質を著しく阻害する。更に、特開平９−２８７０１５
号公報に記載された方法では、溶鋼をＡｌ脱酸した後
に、Ｚｒ、Ｃａ、Ｍｇの一種以上を添加しているので、
脱酸によって生成する酸化物としては、Ａｌ2 Ｏ3 、Ｍ
ｇＯ、ＺｒＯ2 等の単体、あるいはこれ等が結合した複
合の酸化物が生成する。しかし、この方法は、粗大なア
ルミナクラスターを低減するものであって、凝固時の初
晶がオーステナイトである溶鋼の接種核の生成を意図す
るものでない。従って、生成したＺｒＯ2 の単体の酸化
物を溶鋼の接種核として活用できるが、ＭｇＳ等の接種
核を形成することができず、有効な接種核が不足して鋳
片の凝固組織を微細にすることができない。更に、Ａｌ
2 Ｏ3 、ＭｇＯ等の単体の酸化物及びこれ等とＺｒＯ2
の結合した複合酸化物は、オーステナイトの凝固組織に
なる溶鋼に対して、接種核として作用しないため、前述
した特開平７−６２４１７号公報に記載された方法と同
様に、凝固組織が粗大化し、中心偏析やセンターポロシ
ティ、内部割れ等の内部欠陥が発生し、鋳片の品質が著
しく悪化する。このように、従来の溶鋼の処理方法で
は、中心偏析やセンターポロシティ、内部割れ等の内部
欠陥を防止できず、鋳片品質が悪化し、これを用いた鋼
材の溶接部の靱性の低下を抑制できない等の解決できな
い問題がある。However, in the method described in Japanese Patent Application Laid-Open No. 7-62417, when Mg is added, oxides such as SiO 2 , MnO, and Al 2 O 3 are simultaneously formed. The amount of the oxide increases, and this oxide combines with MgO generated in the deoxidation process to form an oxide having a low melting point, and does not function as an inoculum nucleus during solidification of molten steel.
Moreover, oxides acting as inoculation nuclei cannot be preferentially generated in molten steel whose primary crystal during solidification has an austenitic structure. In addition, the cast slab obtained by solidifying the molten steel has a coarse solidified structure, and internal defects such as center segregation, center porosity, and internal cracks occur, thereby significantly impairing the quality of the cast slab. Further, Japanese Patent Application Laid-Open No. 9-287015
In the method described in Japanese Patent Application Publication No. H07-27, one or more of Zr, Ca, and Mg are added after molten steel is deoxidized with Al.
Oxides generated by deoxidation include Al 2 O 3 , M
Simple substances such as gO and ZrO 2 , or composite oxides in which these are combined are formed. However, this method is intended to reduce coarse alumina clusters and is not intended to form inoculation nuclei of molten steel whose primary crystal during solidification is austenite. Therefore, the generated single oxide of ZrO 2 can be used as an inoculation nucleus for molten steel, but an inoculation nucleus such as MgS cannot be formed, and an effective inoculation nucleus is insufficient, and the solidified structure of the slab is finely divided. Can not do it. Furthermore, Al
Simple oxides such as 2 O 3 and MgO, and these and ZrO 2
Does not act as an inoculation nucleus for molten steel that becomes a solidified structure of austenite, so that the solidified structure is coarsened, as in the method described in JP-A-7-62417 described above. Internal defects such as center segregation, center porosity, and internal cracks occur, and the quality of the slab is significantly deteriorated. As described above, the conventional molten steel processing method cannot prevent internal defects such as center segregation, center porosity, and internal cracks, deteriorating the quality of cast slabs, and suppressing a decrease in toughness of a welded portion of a steel material using the same. There are problems that cannot be solved, such as inability.
【０００４】本発明はかかる事情に鑑みてなされたもの
で、溶鋼中に、凝固時の接種核として有効な酸化物や硫
化物を生成させ、凝固した鋳片の凝固組織を微細にして
内部欠陥等の発生を防止し、この鋳片を加工した鋼材の
品質を向上することができる高炭素鋼用溶鋼の処理方法
及び鋳片を提供することを目的とする。The present invention has been made in view of such circumstances, and produces oxides and sulfides effective as inoculation nuclei at the time of solidification in molten steel. It is an object of the present invention to provide a method for treating molten steel for high carbon steel and a slab which can prevent the occurrence of the like and improve the quality of a steel material obtained by processing the slab.
【０００５】[0005]
【課題を解決するための手段】前記目的に沿う本発明に
係る高炭素鋼用溶鋼の処理方法は、炭素を０．５重量％
以上含有する高炭素鋼用の溶鋼の処理方法において、前
記溶鋼中にＺｒを添加してＺｒ酸化物を生成させた後、
該溶鋼にＭｇを添加してＭｇ硫化物を生成させる。この
方法により、溶鋼中に含まれる酸素（Ｏ）をジルコニウ
ム（Ｚｒ）と反応させてＺｒ酸化物（ＺｒＯ2 ）を生成
させ、同時に溶鋼中の酸素濃度を低くしておき、この後
にマグネシウム（Ｍｇ）を添加して溶鋼中の硫黄（Ｓ）
と反応させてＭｇ硫化物（ＭｇＳ）を形成させることが
でき、溶鋼が凝固する際にＺｒＯ2 、ＭｇＳを接種核と
して有効に活用することができる。なお、添加するＺｒ
としては、Ｆｅ−Ｚｒ合金、金属Ｚｒ、Ｍｇとしては、
金属Ｍｇ、Ｆｅ−Ｓｉ−Ｍｇ、Ｎｉ−Ｍｇを含む。According to the present invention, there is provided a method for treating molten steel for high carbon steel, the method comprising:
In the method for treating molten steel for high carbon steel containing above, after adding Zr to the molten steel to generate a Zr oxide,
Mg is added to the molten steel to generate Mg sulfide. According to this method, oxygen (O) contained in the molten steel is reacted with zirconium (Zr) to generate a Zr oxide (ZrO 2 ), and at the same time, the oxygen concentration in the molten steel is lowered, and thereafter, magnesium (Mg) ) To add sulfur (S) in molten steel
To form Mg sulfide (MgS), and when molten steel solidifies, ZrO 2 and MgS can be effectively used as inoculation nuclei. In addition, Zr to be added
As for Fe-Zr alloy, metal Zr, and Mg,
Includes metal Mg, Fe-Si-Mg, Ni-Mg.
【０００６】ここで、前記溶鋼中に含まれるＺｒ重量
％、酸素重量％、Ｍｇ重量％が式（１）を満たすように
調整するのが好ましい。 （２．８４×酸素重量％）＜Ｚｒ重量％＜ （２．８４×酸素重量％＋０．９×Ｍｇ重量％） ・・・・・（１） これにより、溶鋼中のＯがＺｒと反応してＺｒＯ2 を安
定して生成することができ、しかも、後から添加するＭ
ｇがＯと反応するのを抑制してＭｇＯの生成を防止する
ことができる。更に、前記溶鋼中に含まれるＭｇ重量％
とＳ重量％が式（２）を満たすことが好ましい。 （Ｍｇ重量％）×（Ｓ重量％）＞４×１０-5 ・・・・・（２） これにより、Ｍｇを添加した際に、ＭｇＳが溶鋼中に生
成し易くなり、溶鋼が凝固する際にＭｇＳを接種核とし
て有効に活用することができる。Here, it is preferable that Zr weight%, oxygen weight%, and Mg weight% contained in the molten steel are adjusted so as to satisfy the formula (1). (2.84 × weight of oxygen) <Zr weight% <(2.84 × weight of oxygen + 0.9 × weight of Mg) (1) O in the molten steel reacts with Zr. ZrO 2 can be produced stably by the addition, and M
The reaction of g with O can be suppressed to prevent the generation of MgO. Furthermore, the Mg weight% contained in the molten steel
And S weight% preferably satisfy formula (2). (Mg wt%) × (S wt%)> 4 × 10 −5 ... (2) As a result, when Mg is added, MgS is easily generated in the molten steel, and when the molten steel solidifies, In addition, MgS can be effectively used as an inoculum nucleus.
【０００７】上記式（１）、式（２）に示す条件は実験
により求めた値であり、式（１）においてＺｒ重量％を
溶鋼中の酸素重量％の２．８４倍より大きくしたのは、
Ｚｒと酸素が反応してジルコニア（ＺｒＯ2 ）を生成す
る際に、酸素重量に対して化学量論より多くＺｒを添加
して、溶鋼中の酸素を略ＺｒＯ2 として固定するためで
ある。Ｚｒの原子量を９１、酸素の原子量を１６とする
と、化学量論的にＺｒＯ 2 が生成するときのＺｒと酸素
の重量比は、９１／（１６×２）＝２．８４となる。こ
の結果、引き続き溶鋼中にＭｇを添加した際に、Ｍｇが
溶鋼中の酸素と反応しオーステナイト初晶の接種核とし
て作用しないＭｇＯの生成に消費されることが抑制さ
れ、Ｍｇは溶鋼中のＳと反応しオーステナイト初晶の接
種核として有効なＭｇＳを効率的に生成できることにな
る。さらに、Ｚｒ重量％を（２．８４×酸素重量％＋
０．９×Ｍｇ重量％）未満にした理由は、これ以上のＺ
ｒ重量％になると、ＭｇＳの生成よりもＺｒＳの生成が
優先されるため、ＺｒＳの生成に溶鋼中のＳが消費され
Ｍｇ添加時にＭｇＳが効率的に生成しなくなるからであ
る。また、式（２）においてＭｇ重量％とＳ重量％の積
を４×１０-5より大きくした理由は、４×１０-5以下の
場合オーステナイト初晶の接種核として有効なＭｇＳを
凝固開始前に溶鋼中に安定して生成できないためであ
る。The conditions shown in the above equations (1) and (2) are experimental
And the value of Zr wt% in the formula (1)
The reason for making it greater than 2.84 times the weight percent of oxygen in the molten steel is that
Zr reacts with oxygen to form zirconia (ZrOTwo Generate)
More Zr than stoichiometric to oxygen weight
And the oxygen in the molten steel is reduced to approximately ZrOTwo In order to fix as
is there. The atomic weight of Zr is 91 and the atomic weight of oxygen is 16
And stoichiometrically ZrO Two And oxygen in the formation of oxygen
Is 91 / (16 × 2) = 2.84. This
As a result, when Mg was continuously added to the molten steel,
Reacts with oxygen in molten steel to form inoculation nuclei for austenite primary crystals
Is prevented from being consumed for the production of MgO
Mg reacts with S in the molten steel to form an austenite primary crystal.
MgS, which is effective as a seed nucleus, can be produced efficiently.
You. Further, Zr weight% is changed to (2.84 × oxygen weight% +
0.9 × Mg weight%) because the Z
r% by weight, the production of ZrS is more than the production of MgS.
As priority is given, S in molten steel is consumed to produce ZrS.
This is because MgS is not generated efficiently when Mg is added.
You. Further, in the equation (2), the product of Mg weight% and S weight%
Is 4 × 10-FiveThe reason for making it larger is 4 × 10-Fivebelow
MgS effective as inoculation nucleus for austenite primary crystal
This is because it cannot be formed stably in molten steel before solidification starts.
You.
【０００８】前記目的に沿う本発明に係る鋳片は、溶鋼
中にＺｒを添加して、Ｚｒ酸化物を生成させ、更にＭｇ
を添加してＭｇＳを生成させた溶鋼を連続鋳造してい
る。この鋳片は、接種核として有効なＺｒＯ2 、ＭｇＳ
を含んでいるので、鋳片の凝固組織を等軸晶の多い微細
な組織にすることができ、中心偏析やセンターポロシテ
ィ、内部割れ等の内部欠陥の発生を防止し、鋳片の品質
を向上する。しかも、鋳片を圧延加工した鋼材の溶接部
の靱性の低下を防止することができる。In the slab according to the present invention, which meets the above object, Zr is added to molten steel to form a Zr oxide, and further, Mg is added.
Is continuously cast into molten steel in which MgS is generated by adding Mg. This slab is made of ZrO 2 , MgS
As a result, the solidified structure of the slab can be made into a fine structure with many equiaxed crystals, preventing the occurrence of internal defects such as center segregation, center porosity, and internal cracks, and improving the quality of the slab. I do. Moreover, it is possible to prevent a decrease in toughness of a welded portion of a steel material obtained by rolling a slab.
【０００９】[0009]
【発明の実施の形態】続いて、添付した図面を参照しつ
つ、本発明を具体化した実施の形態につき説明し、本発
明の理解に供する。図１は本発明の一実施の形態に係る
高炭素鋼用溶鋼の処理方法に適用される溶鋼の処理装置
の全体図、図２は本発明の一実施の形態に係る鋳片を鋳
造する連続鋳造装置の全体図である。図１に示すよう
に、本発明の一実施の形態に係る高炭素鋼用溶鋼の処理
方法に適用される溶鋼の処理装置１０は、溶鋼１１を貯
留可能な取鍋１２と、取鍋１２の上方に、Ｚｒの一例で
あるＺｒ合金の表面を薄鋼板で覆ったＺｒ合金ワイヤ、
及びＭｇの一例である金属Ｍｇの表面を薄鋼板で覆った
Ｍｇワイヤを案内するガイドパイプ１３を備え、Ｚｒ合
金ワイヤ、及びＭｇワイヤを送り出して取鍋１２内のス
ラグ１４を貫通して溶鋼１１に供給するドラム式供給装
置１５とを有している。なお、ドラム式供給装置１５
は、図示しない駆動源に接続し、しかも、クイックチェ
ンジすることができるドラムを内蔵しており、容易にワ
イヤの種類を取り替えることができる。DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention. FIG. 1 is an overall view of an apparatus for processing molten steel applied to a method for processing molten steel for high carbon steel according to one embodiment of the present invention, and FIG. 2 is a continuous view for casting a slab according to one embodiment of the present invention. It is an overall view of a casting device. As shown in FIG. 1, a molten steel processing apparatus 10 applied to a method for processing molten steel for high carbon steel according to one embodiment of the present invention includes a ladle 12 capable of storing molten steel 11, Above, a Zr alloy wire in which the surface of a Zr alloy as an example of Zr is covered with a thin steel sheet,
And a guide pipe 13 for guiding an Mg wire in which the surface of a metal Mg, which is an example of Mg, is covered with a thin steel plate. The Zr alloy wire and the Mg wire are sent out and penetrated through a slag 14 in a ladle 12 to form a molten steel 11 And a drum-type supply device 15 for supplying the same to the apparatus. In addition, the drum type supply device 15
Has a built-in drum that can be connected to a drive source (not shown) and that can be changed quickly, so that the type of wire can be easily changed.
【００１０】次に、本発明の一実施の形態に係る高炭素
鋼用溶鋼の処理方法について説明する。炭素を０．５重
量％含む高炭素鋼用溶鋼の溶鋼１１を取鍋１２に入れ、
Ｚｒ合金ワイヤをドラム式供給装置１５から２ｋｇ／分
の速度で送り出し、ガイドパイプ１３で案内しながら溶
鋼１１に装入して、添加されたＺｒ合金中のＺｒにより
溶鋼１１に含まれるＯの脱酸を行った。このＺｒは、溶
鋼１１に含まれるＳよりもＯとの結合力が強いため、溶
鋼１１中のＯと反応してＺｒＯ2 を生成し、溶鋼１１が
凝固する際に接種核として有効に作用する。Ｚｒを添加
した後に、ドラム式供給装置１５のドラムを金属Ｍｇワ
イヤを巻いたドラムに交換する。そして、ドラム式供給
装置１５から２ｋｇ／分の速度で金属Ｍｇワイヤを送り
出してガイドパイプ１３で案内しながら溶鋼１１内に装
入する。添加された金属Ｍｇは、溶鋼１１中に含まれる
Ｓと反応してＭｇＳを生成し、溶鋼１１が凝固する際の
接種核として有効に作用する。Next, a method for treating molten steel for high carbon steel according to one embodiment of the present invention will be described. The molten steel 11 of the molten steel for high carbon steel containing 0.5% by weight of carbon is put into the ladle 12,
The Zr alloy wire is sent out from the drum type supply device 15 at a rate of 2 kg / min, and is charged into the molten steel 11 while being guided by the guide pipe 13, so that Zr in the added Zr alloy removes O contained in the molten steel 11. The acid was run. Since Zr has a stronger binding force with O than S contained in the molten steel 11, it reacts with O in the molten steel 11 to generate ZrO 2, and effectively acts as an inoculum nucleus when the molten steel 11 solidifies. . After adding Zr, the drum of the drum-type supply device 15 is replaced with a drum around which a metal Mg wire is wound. Then, the metal Mg wire is sent out from the drum type supply device 15 at a rate of 2 kg / min, and charged into the molten steel 11 while being guided by the guide pipe 13. The added metal Mg reacts with S contained in the molten steel 11 to generate MgS, and effectively acts as an inoculum nucleus when the molten steel 11 solidifies.
【００１１】なお、Ｚｒ及びＭｇの添加前に、溶鋼１１
をサンプリングして、分析を行って酸素重量％を求めて
おき、Ｚｒ、Ｍｇ歩留りの過去の実績等を用いて、溶鋼
中に含まれるＺｒ重量％、酸素重量％、Ｍｇ重量％が下
式の関係を満たすようにＺｒ及びＭｇを添加する。 （２．８４×酸素重量％）＜Ｚｒ重量％＜（２．８４×
酸素重量％＋０．９×Ｍｇ重量％） その結果、溶鋼１１中に添加するＺｒの量が多くなるの
を抑制し、ＺｒＯ2 を安定して生成させることができ
る。そして、ＺｒＯ2 が生成された溶鋼１１にＭｇを添
加することにより、溶鋼１１中のＯとの反応によるＭｇ
Ｏの生成を抑制することができ、溶鋼１１中のＳと反応
させてＭｇＳの生成を促進できる。特に、Ｚｒの添加量
が過剰になる場合は、Ｚｒの一部が溶鋼１１中に含まれ
るＳと反応してＺｒＳ2 が生成し、接種核として作用し
なくなり、しかも、溶鋼１１中のＳがＺｒとの反応に消
費されて、ＭｇＳの生成が阻害される。従って、更に溶
鋼１１中に効率良くＭｇＳを生成するために、Ｍｇの添
加を下式を満たすように行う。 （Ｍｇ重量％）×（Ｓ重量％）＞４×１０-5 Ｍｇ重量％とＳ重量％を所定の範囲にすることにより、
金属Ｍｇを添加した際に、ＭｇＳが溶鋼中に安定して生
成される。生成したＺｒＯ2 、ＭｇＳは、オーステナイ
トとの結晶格子歪みが小さいため、溶鋼１１内に分散し
て炭素を０．５重量％含む凝固時の初晶がオーステナイ
ト相の溶鋼の接種核として作用する。その結果、これ等
の接種核を起点に凝固が開始され、ピンニング作用との
相乗した働きによって、凝固組織を非常に微細な等軸晶
にすることができる。Before the addition of Zr and Mg, molten steel 11
Sample and perform an analysis to determine oxygen percent by weight
Using the past results of Zr, Mg yield, etc.
Zr wt%, oxygen wt%, Mg wt% contained in
Zr and Mg are added so as to satisfy the relationship of the formula. (2.84 x oxygen weight%) <Zr weight% <(2.84 x
(Oxygen weight% + 0.9 × Mg weight%) As a result, the amount of Zr added to the molten steel 11 increases.
And ZrOTwo Can be generated stably
You. And ZrOTwo Mg is added to the molten steel 11 in which
By adding, Mg by reaction with O in molten steel 11
O generation can be suppressed and reacts with S in molten steel 11
As a result, generation of MgS can be promoted. In particular, the amount of Zr added
Is excessive, a part of Zr is contained in the molten steel 11.
Reacts with STwo Is produced and acts as an inoculum nucleus
And the S in the molten steel 11 disappears in the reaction with Zr.
Spent, the production of MgS is inhibited. Therefore, further melting
In order to efficiently generate MgS in the steel 11, Mg is added.
Addition is performed so as to satisfy the following equation. (Mg weight%) × (S weight%)> 4 × 10-Five By setting the Mg weight% and the S weight% within a predetermined range,
When metal Mg is added, MgS is produced stably in molten steel.
Is done. Generated ZrOTwo , MgS is austenitic
The crystal lattice distortion with the
The primary crystal during solidification containing 0.5% by weight of carbon is austenitic.
It acts as an inoculation nucleus for molten steel in the G phase. As a result, these
Coagulation starts from the inoculation nucleus of
By synergistic action, solidification structure can be made very fine equiaxed
Can be
【００１２】次に、本発明の一実施の形態に係る鋳片２
５を鋳造する連続鋳造装置２０について説明する。図２
に示すように、連続鋳造装置２０は、溶鋼１１を貯湯す
るタンディッシュ２１と鋳型２２を有し、タンディッシ
ュ２１の底部に鋳型２２に注湯する浸漬ノズル２３と、
溶鋼１１に図示しない冷却ノズルから散水して溶鋼１１
の凝固殻１１ａの成長を促進する支持セグメント２４を
備えており、図示しないピンチロールによって鋳片２５
を一定の速度で引き抜きながら鋳造を行う装置である。
本実施の形態に係る鋳片２５は、前記連続鋳造装置２０
によって以下のように連続鋳造される。まず、炭素を
０．５重量％含んだ溶鋼１１に、Ｚｒ合金ワイヤを２ｋ
ｇ／溶鋼トン添加して脱酸を行い、その後に金属Ｍｇを
２ｋｇ／溶鋼トン添加して、ＺｒＯ2 、ＭｇＳを生成さ
せて、この溶鋼１１をタンディッシュ２１に貯湯して浸
漬ノズル２３から鋳型２２に注湯した。そして、鋳型２
２による冷却と支持セグメント２４に配置した冷却ノズ
ルからの散水により、溶鋼１１が凝固して凝固殻１１ａ
を形成し、更に冷却ノズルからの散水によって、凝固殻
１１ａの成長が促進され、完全に凝固したものをピンチ
ロールで０．６ｍ／分の速度で引き抜きながら鋳片２５
を鋳造した。この鋳片２５を切断し、その断面の凝固組
織を調査した結果、全体が微細な等軸晶であり、凝固過
程で内部に形成される内部割れや中心偏析、センターポ
ロシティ等の内部欠陥が無く、優れた凝固組織を備えて
いることが確認された。更に、この鋳片２５に圧延等の
加工を施した鋼材には、内部欠陥が無く、鋼材を溶接し
た際の溶接部における靱性が低下するのを防止すること
ができた。Next, a slab 2 according to an embodiment of the present invention will be described.
5 will be described. FIG.
As shown in FIG. 1, the continuous casting apparatus 20 has a tundish 21 for storing molten steel 11 and a mold 22, and an immersion nozzle 23 for pouring the mold 22 at the bottom of the tundish 21,
Water is sprinkled from a cooling nozzle (not shown) on the molten steel
And a support segment 24 for promoting the growth of the solidified shell 11a.
This is a device that performs casting while drawing at a constant speed.
The slab 25 according to the present embodiment is a
Is continuously cast as follows. First, 2 k of Zr alloy wire was added to molten steel 11 containing 0.5% by weight of carbon.
g / ton of molten steel and deoxidation, then add 2 kg of metallic Mg / ton of molten steel to generate ZrO 2 and MgS, store the molten steel 11 in the tundish 21 and mold it through the immersion nozzle 23. 22 was poured. And mold 2
2 and the water spray from the cooling nozzle arranged in the support segment 24 solidifies the molten steel 11 to form a solidified shell 11a.
The growth of the solidified shell 11a is promoted by water spray from the cooling nozzle, and the completely solidified shell 11a is drawn out with a pinch roll at a speed of 0.6 m / min.
Was cast. As a result of investigating the solidified structure of the cross section of the slab 25, the whole was fine equiaxed, and there were no internal defects such as internal cracks, center segregation, and center porosity formed inside during the solidification process. It was confirmed that it had an excellent solidified structure. Further, the steel material obtained by subjecting the slab 25 to rolling or the like did not have any internal defects, and it was possible to prevent a decrease in toughness in a welded portion when the steel material was welded.
【００１３】[0013]
【実施例】次に、本発明に係る高炭素鋼用溶鋼の処理方
法によって連続鋳造した鋳片の調査結果について説明す
る。炭素を０．７９重量％含み表１に示す組成の高炭素
鋼用の溶鋼３５０トンを取鍋に入れ、この溶鋼中にＺｒ
合金ワイヤによりＺｒを添加して脱酸を行った後、金属
ＭｇワイヤによりＭｇを添加して、溶鋼中のＺｒ重量
％、Ｍｇ重量％を所定の濃度に調整して、溶鋼中にＺｒ
Ｏ2 、ＭｇＳを生成させた。この溶鋼を内寸が厚み３６
０ｍｍ、幅４８０ｍｍの鋳型に注湯し、支持セグメント
での散水による冷却によって凝固殻の成長を促進して凝
固させ、０．８ｍの速度でピンチロールにより引き抜い
て鋳片を鋳造した。この鋳片を切断してピクリン酸でエ
ッチングを行い、電子顕微鏡により切断面の凝固組織の
結晶の大きさ及び中心偏析等の内部欠陥を観察した。そ
して、Ｚｒ添加重量％、Ｍｇ添加重量％、鋳片の凝固組
織、内部品質、鋼材の溶接部靱性、総合評価について表
２に示す。実施例１及び実施例２は、Ｚｒを添加した後
にＭｇを添加し、しかも、ＺｒとＭｇの添加濃度が本発
明の範囲を満足した場合であり、溶鋼の凝固前に細かな
ＺｒＯ2 、ＭｇＳが多数生成しており、鋳片の凝固組織
が微細な等軸晶になり、内部品質は中心偏析やセンター
ポロシティ、内部割れ等が無く非常に良好になり、各鋳
片から製造した鋼材のサンプルを測定した場合溶接部の
靱性も良好であり、総合評価として良い（○）結果にな
った。Next, the results of investigations on cast slabs continuously cast by the method for processing molten steel for high carbon steel according to the present invention will be described. 350 tons of molten steel for high carbon steel containing 0.79% by weight of carbon and having the composition shown in Table 1 was placed in a ladle, and Zr was added to the molten steel.
After Zr is added and deoxidized by an alloy wire, Mg is added by a metal Mg wire to adjust the Zr weight% and the Mg weight% in the molten steel to predetermined concentrations, and Zr is added to the molten steel.
O 2 and MgS were generated. The inner diameter of this molten steel is 36
The molten metal was poured into a mold having a width of 0 mm and a width of 480 mm, and the growth of a solidified shell was promoted and solidified by cooling by spraying water on a support segment. The solidified shell was cast by a pinch roll at a speed of 0.8 m. The slab was cut and etched with picric acid, and the electron microscope was used to observe the crystal size of the solidified structure on the cut surface and internal defects such as center segregation. Table 2 shows Zr addition weight%, Mg addition weight%, solidification structure of cast slab, internal quality, weld toughness of steel material, and comprehensive evaluation. Example 1 and Example 2 are cases where Mg is added after Zr is added, and the addition concentration of Zr and Mg satisfies the range of the present invention, and fine ZrO 2 and MgS are added before solidification of molten steel. The solidification structure of the slab becomes a fine equiaxed crystal, the internal quality is very good without center segregation, center porosity, internal cracks, etc., and a sample of steel material manufactured from each slab Was measured, the toughness of the welded portion was also good, and the result was good (○) as the overall evaluation.
【００１４】[0014]
【表１】 [Table 1]
【００１５】[0015]
【表２】 [Table 2]
【００１６】これに対し、比較例１は、Ｚｒ添加重量
％、Ｍｇ添加重量％は本発明の範囲を満足しているが、
Ｍｇを最初に添加し、その後にＺｒを添加した場合であ
り、溶鋼中にＭｇＯやＺｒＳ2 が生成して凝固組織が粗
大になり、中心偏析やセンターポロシティ、内部割れ等
の欠陥が生じて内部品質が不良であり、鋼材の溶接部の
靱性も不良になり、総合評価として悪い（×）結果にな
った。比較例２は、溶鋼にＺｒのみを添加した場合、比
較例３は、溶鋼にＭｇのみを添加した場合であり、いず
れとも鋳片の一部しか凝固組織を等軸晶にできず、内部
品質及び鋼材の溶接部の靱性はやや改善したものの総合
評価としてやや悪い（△）結果になった。比較例４は、
溶鋼にＭｇのみを添加し、しかも、Ｍｇ添加重量％が
０．００４１重量％と低い場合であり、ＭｇＯが生成し
て接種核として作用せず、鋳片の凝固組織が粗大にな
り、内部品質及び鋼材の溶接部の靱性が不良であり、総
合評価として悪い（×）結果になった。比較例５は、溶
鋼に何も添加しなかった場合であり、接種核が生成され
ず、鋳片の凝固組織が粗大になり、内部品質及び鋼材の
溶接部の靱性が不良であり、総合評価として悪い（×）
結果になった。On the other hand, Comparative Example 1 satisfies the range of the present invention in which Zr added weight% and Mg added weight% satisfy the range of the present invention.
This is the case where Mg is added first, and then Zr is added. MgO or ZrS 2 is generated in the molten steel, the solidification structure becomes coarse, and defects such as center segregation, center porosity, and internal cracks occur, and The quality was poor, the toughness of the welded portion of the steel material was also poor, and the overall evaluation was poor (x). Comparative Example 2 was a case where only Zr was added to the molten steel, and Comparative Example 3 was a case where only Mg was added to the molten steel. Although the toughness of the welded portion of the steel material was slightly improved, the overall evaluation was somewhat poor (△). Comparative Example 4
This is the case where only Mg is added to molten steel, and the Mg addition weight% is as low as 0.0041% by weight, MgO is not generated and does not act as an inoculum nucleus, the solidified structure of the slab becomes coarse, and the internal quality is reduced. Also, the toughness of the welded portion of the steel material was poor, and the overall evaluation was poor (x). Comparative Example 5 is a case where nothing was added to the molten steel, inoculation nuclei were not generated, the solidified structure of the slab became coarse, the internal quality and the toughness of the welded portion of the steel material were poor, and the overall evaluation was performed. As bad (×)
The result was.
【００１７】以上、本発明の実施の形態を説明したが、
本発明は、上記した形態に限定されるものでなく、要旨
を逸脱しない条件の変更等は全て本発明の適用範囲であ
る。例えば、ＺｒあるいはＭｇの添加方法としては、ワ
イヤ添加の他に、先端に吹き込み孔を有する浸漬ランス
を用いて、Ｆｅ−Ｚｒ合金、金属Ｚｒ、金属Ｍｇ、Ｆｅ
−Ｓｉ−Ｍｇ、Ｎｉ−Ｍｇ等の粉、又は粒を溶鋼中に吹
き込んで添加することができる。The embodiment of the present invention has been described above.
The present invention is not limited to the above-described embodiment, and all changes in conditions that do not depart from the gist are within the scope of the present invention. For example, as a method of adding Zr or Mg, in addition to the addition of a wire, an immersion lance having a blowing hole at the tip is used to add Fe-Zr alloy, metal Zr, metal Mg, Fe
Powder or grains such as -Si-Mg, Ni-Mg can be added by blowing into molten steel.
【００１８】[0018]
【発明の効果】請求項１〜３記載の高炭素鋼用溶鋼の処
理方法は、炭素を０．５重量％以上含有する高炭素鋼用
溶鋼の処理方法において、溶鋼中にＺｒを添加してＺｒ
酸化物を生成させた後、溶鋼にＭｇを添加してＭｇ硫化
物を生成させるので、溶鋼中に、接種核として有効な酸
化物や硫化物を生成させて、鋳片の凝固組織を微細にし
て、中心偏析やセンターポロシティ、内部割れ等の内部
欠陥を防止して鋳片品質及び鋼材の品質を向上すること
ができる。更に、接種核としてのＭｇの歩留りを高め、
使用するＭｇ合金等を節減してコストを低減することが
できる。The method for treating molten steel for high carbon steel according to any one of claims 1 to 3, further comprising the step of adding Zr to the molten steel in the method for treating molten steel for high carbon steel containing 0.5% by weight or more of carbon. Zr
After the oxide is generated, Mg is added to the molten steel to generate Mg sulfide.In the molten steel, an oxide or sulfide effective as an inoculum nucleus is generated, and the solidified structure of the slab is refined. Thus, it is possible to prevent internal defects such as center segregation, center porosity, and internal cracks, thereby improving the quality of cast slabs and steel. Furthermore, increase the yield of Mg as an inoculum nucleus,
The cost can be reduced by saving the Mg alloy to be used.
【００１９】特に、請求項２記載の高炭素鋼用溶鋼の処
理方法は、溶鋼中に含まれるＺｒ重量％、酸素重量％、
Ｍｇ重量％を所定の範囲に調整するので、ＺｒＯ2 を安
定して生成し、その後に、ＭｇＳの生成を促進して、鋳
片の凝固組織を安定して微細にすることができる。In particular, the method for treating molten steel for high carbon steel according to claim 2 is characterized in that the weight percent of Zr, the weight percent of oxygen contained in the molten steel,
Since the Mg weight% is adjusted to a predetermined range, ZrO 2 can be generated stably, and thereafter, the generation of MgS can be promoted, and the solidified structure of the slab can be stably made fine.
【００２０】請求項３記載の高炭素鋼用溶鋼の処理方法
は、溶鋼中に含まれるＭｇ重量％とＳ重量％を所定の範
囲にしているので、溶鋼中にＺｒＯ2 及びＭｇＳを安定
して形成し、鋳片の凝固組織を極めて微細にすることが
でき、内部欠陥を確実に無くし、鋳片の品質を向上する
ことができる。In the method for treating molten steel for high carbon steel according to the third aspect of the present invention, since the weight percent of Mg and the weight percent of S contained in the molten steel are within a predetermined range, ZrO 2 and MgS are stably contained in the molten steel. When formed, the solidified structure of the slab can be made extremely fine, internal defects can be reliably eliminated, and the quality of the slab can be improved.
【００２１】請求項４記載の鋳片は、溶鋼中にＺｒを添
加して、Ｚｒ酸化物を生成させ、更にＭｇを添加してＭ
ｇＳを生成させた溶鋼を連続鋳造しており、接種核とし
て有効なＺｒＯ2 、ＭｇＳが形成された溶鋼を用い、鋳
片を鋳造しているため、凝固組織を等軸晶の多い微細な
組織にでき、内部欠陥の発生を防止でき、鋳片の品質を
安定して向上することができる。しかも、鋳片を圧延加
工した鋼材に発生する内部欠陥を無くし、溶接した際の
溶接部の靱性の低下を防止して鋼材の品質を向上するこ
とができる。In the slab according to the fourth aspect, Zr is added to the molten steel to generate a Zr oxide, and Mg is further added to add Mr.
Since the molten steel that produced gS is continuously cast, and the molten steel in which ZrO 2 and MgS effective as inoculation nuclei are formed and the slab is cast, the solidified structure has a fine structure with many equiaxed crystals. And the occurrence of internal defects can be prevented, and the quality of the slab can be stably improved. In addition, it is possible to eliminate internal defects generated in the steel material obtained by rolling the cast slab, prevent a decrease in toughness of a welded portion at the time of welding, and improve the quality of the steel material.
【図１】本発明の一実施の形態に係る高炭素鋼用溶鋼の
処理方法に適用される溶鋼の処理装置の全体図である。FIG. 1 is an overall view of an apparatus for treating molten steel applied to a method for treating molten steel for high carbon steel according to an embodiment of the present invention.
【図２】本発明の一実施の形態に係る鋳片を鋳造する連
続鋳造装置の全体図である。FIG. 2 is an overall view of a continuous casting apparatus for casting a slab according to one embodiment of the present invention.
１０：溶鋼の処理装置、１１：溶鋼、１１ａ：凝固殻、
１２：取鍋、１３：ガイドパイプ、１４：スラグ、１
５：ドラム式供給装置、２０：連続鋳造装置、２１：タ
ンディッシュ、２２：鋳型、２３：浸漬ノズル、２４：
支持セグメント、２５：鋳片10: molten steel processing apparatus, 11: molten steel, 11a: solidified shell,
12: Ladle, 13: Guide pipe, 14: Slag, 1
5: drum type feeding device, 20: continuous casting device, 21: tundish, 22: mold, 23: immersion nozzle, 24:
Support segment, 25: slab
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 ＦＩ テーマコート゛(参考） Ｃ２１Ｃ 7/00 Ｃ２１Ｃ 7/00 Ｈ Ｃ２２Ｃ 38/00 ３０１ Ｃ２２Ｃ 38/00 ３０１Ｂ 38/14 38/14 ──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. 7 Identification symbol FI Theme coat ゛ (Reference) C21C 7/00 C21C 7/00 H C22C 38/00 301 C22C 38/00 301B 38/14 38/14
Claims (4)
鋼用の溶鋼の処理方法において、前記溶鋼中にＺｒを添
加してＺｒ酸化物を生成させた後、該溶鋼にＭｇを添加
してＭｇ硫化物を生成させることを特徴とする高炭素鋼
用溶鋼の処理方法。1. A method for treating molten steel for high carbon steel containing 0.5% by weight or more of carbon, wherein Zr is added to the molten steel to form a Zr oxide, and then Mg is added to the molten steel. A method for treating molten steel for high carbon steel, comprising: forming Mg sulfide.
法において、前記溶鋼中に含まれるＺｒ重量％、酸素重
量％、Ｍｇ重量％が式（１）を満たすように調整されて
いることを特徴とする高炭素鋼用溶鋼の処理方法。 （２．８４×酸素重量％）＜Ｚｒ重量％＜ （２．８４×酸素重量％＋０．９×Ｍｇ重量％） ・・・・・（１）2. The method for treating molten steel for high carbon steel according to claim 1, wherein Zr wt%, oxygen wt%, and Mg wt% contained in the molten steel are adjusted to satisfy the formula (1). A method for treating molten steel for high carbon steel, characterized in that: (2.84 × weight of oxygen) <Zr weight% <(2.84 × weight of oxygen + 0.9 × weight of Mg) (1)
処理方法において、前記溶鋼中に含まれるＭｇ重量％と
Ｓ重量％が式（２）を満たすことを特徴とする高炭素鋼
用溶鋼の処理方法。 （Ｍｇ重量％）×（Ｓ重量％）＞４×１０-5 ・・・・・（２）3. The method for treating molten steel for high carbon steel according to claim 1, wherein the Mg weight% and the S weight% contained in the molten steel satisfy the formula (2). Method of processing molten steel. (Mg wt%) × (S wt%)> 4 × 10 −5 (2)
生成させ、更にＭｇを添加してＭｇＳを生成させた溶鋼
を連続鋳造したことを特徴とする鋳片。4. A slab, wherein Zr is added to molten steel to form a Zr oxide, and Mg is further added to form MgS to continuously cast a molten steel.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004300502A (en) * | 2003-03-31 | 2004-10-28 | Nippon Steel Corp | Steel manufacturing method |
| EP1589124A1 (en) * | 2003-01-27 | 2005-10-26 | Nippon Steel Corporation | High strength high toughness high carbon steel wire rod and process for producing the same |
-
2000
- 2000-10-24 JP JP2000324161A patent/JP4264189B2/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1589124A1 (en) * | 2003-01-27 | 2005-10-26 | Nippon Steel Corporation | High strength high toughness high carbon steel wire rod and process for producing the same |
| EP1589124A4 (en) * | 2003-01-27 | 2007-10-17 | Nippon Steel Corp | HIGH-CARBON HIGH-STRENGTH CARBON STEEL YARN AND PROCESS FOR MANUFACTURING THE SAME |
| JP2004300502A (en) * | 2003-03-31 | 2004-10-28 | Nippon Steel Corp | Steel manufacturing method |
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