JP2013224480A - Method for producing steel for saw wire - Google Patents
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- JP2013224480A JP2013224480A JP2012190163A JP2012190163A JP2013224480A JP 2013224480 A JP2013224480 A JP 2013224480A JP 2012190163 A JP2012190163 A JP 2012190163A JP 2012190163 A JP2012190163 A JP 2012190163A JP 2013224480 A JP2013224480 A JP 2013224480A
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 138
- 239000010959 steel Substances 0.000 title claims abstract description 138
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 14
- 238000007670 refining Methods 0.000 claims abstract description 129
- 239000002893 slag Substances 0.000 claims abstract description 77
- 239000013078 crystal Substances 0.000 claims abstract description 43
- 238000003756 stirring Methods 0.000 claims abstract description 38
- 239000002994 raw material Substances 0.000 claims abstract description 18
- 239000000203 mixture Substances 0.000 claims abstract description 17
- 238000000034 method Methods 0.000 claims description 93
- 230000008569 process Effects 0.000 claims description 79
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 38
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 17
- 239000002245 particle Substances 0.000 claims description 13
- 239000011819 refractory material Substances 0.000 claims description 13
- 238000010276 construction Methods 0.000 abstract description 2
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 30
- 230000000052 comparative effect Effects 0.000 description 29
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 22
- 239000000463 material Substances 0.000 description 19
- 239000000395 magnesium oxide Substances 0.000 description 15
- 238000003723 Smelting Methods 0.000 description 13
- 239000002184 metal Substances 0.000 description 12
- 229910052751 metal Inorganic materials 0.000 description 12
- 229910052742 iron Inorganic materials 0.000 description 11
- 238000002844 melting Methods 0.000 description 11
- 230000008018 melting Effects 0.000 description 11
- 229910052710 silicon Inorganic materials 0.000 description 10
- 238000002407 reforming Methods 0.000 description 9
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 8
- 239000011449 brick Substances 0.000 description 8
- 239000010703 silicon Substances 0.000 description 8
- 238000007664 blowing Methods 0.000 description 6
- 229910000655 Killed steel Inorganic materials 0.000 description 5
- 238000005520 cutting process Methods 0.000 description 5
- 230000003749 cleanliness Effects 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 239000011261 inert gas Substances 0.000 description 4
- 230000004048 modification Effects 0.000 description 4
- 238000012986 modification Methods 0.000 description 4
- 229910052596 spinel Inorganic materials 0.000 description 4
- 239000011029 spinel Substances 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 230000002411 adverse Effects 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 238000009749 continuous casting Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 239000002270 dispersing agent Substances 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 238000004901 spalling Methods 0.000 description 2
- 230000001629 suppression Effects 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 238000012795 verification Methods 0.000 description 2
- 235000012431 wafers Nutrition 0.000 description 2
- 238000005491 wire drawing Methods 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910001341 Crude steel Inorganic materials 0.000 description 1
- 229910000677 High-carbon steel Inorganic materials 0.000 description 1
- 101150006573 PAN1 gene Proteins 0.000 description 1
- 229910001327 Rimmed steel Inorganic materials 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 229910003481 amorphous carbon Inorganic materials 0.000 description 1
- 229910001570 bauxite Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000006837 decompression Effects 0.000 description 1
- 238000007872 degassing Methods 0.000 description 1
- UAMZXLIURMNTHD-UHFFFAOYSA-N dialuminum;magnesium;oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[O-2].[Mg+2].[Al+3].[Al+3] UAMZXLIURMNTHD-UHFFFAOYSA-N 0.000 description 1
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000005674 electromagnetic induction Effects 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 238000001764 infiltration Methods 0.000 description 1
- 230000008595 infiltration Effects 0.000 description 1
- 150000002500 ions Chemical group 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052863 mullite Inorganic materials 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000002250 progressing effect Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 238000001004 secondary ion mass spectrometry Methods 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Treatment Of Steel In Its Molten State (AREA)
- Furnace Housings, Linings, Walls, And Ceilings (AREA)
- Ceramic Products (AREA)
Abstract
Description
本発明は、例えば、シリコン太陽電池、半導体シリコンウェハなどを精密に切断加工するための切断刃として使われるソーワイヤの元材となるソーワイヤ用鋼の製造方法に関する。 The present invention relates to a method for manufacturing steel for saw wire, which is a base material of saw wire used as a cutting blade for precisely cutting a silicon solar cell, a semiconductor silicon wafer, or the like.
従来より、転炉などで脱炭処理した溶鋼を取鍋に出鋼し、当該取鍋を二次精錬ステーションに移動させて、二次精錬処理を行うことによって線材に用いられる高清浄度鋼を製造している。高清浄度鋼を製造する技術（精錬する技術）として、例えば、特許文献１〜５に示すものがある。
特許文献１では、精錬後の溶鋼を取鍋から排出して連続鋳造した後、取鍋を転炉に再び戻して溶鋼を受鋼する工程を１サイクルとする操業方法が開示されている。この操業では、複数の取鍋を組み合わせて循環使用しており、シリコンキルド鋼について連続して複数回繰り返すに際して、この繰り返しが終了するまでは、シリコンキルド鋼を受鋼する取鍋は、前回のチャージで受鋼する鋼種がシリコンキルド鋼またはリムド鋼のみであることとしている。
Conventionally, high cleanliness steel used for wire rods is obtained by removing molten steel decarburized in a converter, etc. into a ladle, moving the ladle to a secondary refining station, and performing secondary refining treatment. Manufacture. Examples of techniques for manufacturing high cleanliness steel (refining techniques) include those shown in Patent Documents 1 to 5.
Patent Document 1 discloses an operation method in which a cycle in which molten steel after refining is discharged from a ladle and continuously casted and then the ladle is returned to the converter and the molten steel is received is one cycle. In this operation, a plurality of ladles are combined and circulated, and when the silicon killed steel is repeated several times in succession, the ladle receiving the silicon killed steel is the last one until this repetition is completed. It is assumed that the steel grade to receive by charge is only silicon killed steel or rimmed steel.
特許文献２では、鋼線材の元となる溶鋼の精錬処理を行うにあたり、精錬処理は取鍋ガス攪拌精錬、減圧槽内取鍋ガス攪拌精錬、取鍋内電磁誘導攪拌精錬、還流式脱ガス精錬のいずれか１つ又は２つ以上を組み合わせたものとし、各精錬における攪拌動力に関する指標Ｅを８００〜１５００の範囲内にする技術を開示している。
特許文献３では、Ｃを０．６０〜１．０質量％含有する高炭素鋼を製造するに当たり、取鍋精錬でのスラグの最終組成を、塩基度が０．７〜１．４、Ａｌ２Ｏ３が２〜１０質量％となるようにし、ＣａＯの質量がスラグ全体の２０％以下とする技術を開示している。
In Patent Document 2, when refining the molten steel that is the source of the steel wire rod, the refining process is ladle gas stirring refining, ladle gas stirring refining in a decompression tank, ladle electromagnetic induction stirring refining, reflux degassing refining 1 or a combination of two or more thereof, and discloses a technique for setting an index E relating to stirring power in each refining within a range of 800 to 1500.
In patent document 3, in producing high carbon steel containing 0.60 to 1.0% by mass of C, the final composition of slag in ladle refining has a basicity of 0.7 to 1.4, Al 2 O 3 is set to be 2 to 10 mass%, discloses a technique in which the mass of CaO is 20% or less of the total slag.
特許文献４では、精錬後の溶鋼中の[Ｓｉ]を０．８〜３．０質量％に設定すると共に、精錬に使用するスラグの塩基度を前記溶鋼の[Ｓｉ]に基づいて所定範囲内に設定し、攪拌精錬における攪拌動力量Ｅをスラグの塩基度に基づいて所定範囲内に設定する技術を開示している。
特許文献５では、最終鋼塊成分をＣ：０．３〜１．０％、Ｓｉ：０．１〜２．５％，Ｍｎ：０．１〜１．５％とする共に、Ａｌの含有量を二次イオン質量分析法による測定値で２．３〜６ｐｐｍになる様に制御し、高清浄鋼の製造を行う技術を開示している。
In Patent Document 4, [Si] in the molten steel after refining is set to 0.8 to 3.0 mass%, and the basicity of the slag used for refining is within a predetermined range based on [Si] of the molten steel. And a technique for setting the stirring power amount E in the stirring and refining within a predetermined range based on the basicity of the slag.
In Patent Document 5, the final steel ingot component is C: 0.3 to 1.0%, Si: 0.1 to 2.5%, Mn: 0.1 to 1.5%, and the content of Al Is controlled to be 2.3 to 6 ppm as measured by secondary ion mass spectrometry, and a technique for producing highly clean steel is disclosed.
さて、上述したように二次精錬処理では取鍋内の溶鋼に対して精錬処理を行うが、使用する取鍋内の耐火物に関する技術として、特許文献６及び７に示すものがある。
特許文献６に開示された耐火物では、電融アルミナ，焼結アルミナ，電融スピネル，焼結スピネル，電融スピネル，電融マグネシアおよび焼結マグネシアの中から選ばれた１種または２種以上の主骨材１００重量％に対し、分散剤０．０５〜０．５重量％、平均粒径０．５μｍ以下の仮焼アルミナを３〜１０重量％、Ａｌ２ Ｏ３＋ＣａＯの合量が９９重量％以上の高純度アルミナセメントをＣａＯ量として１重量％を越えない範囲で添加し、さらに添加水分が４．５重量％以下としている。
Now, as described above, in the secondary refining process, the refining process is performed on the molten steel in the ladle. As techniques relating to the refractory in the ladle to be used, there are those shown in Patent Documents 6 and 7.
In the refractory disclosed in Patent Document 6, one or more selected from fused alumina, sintered alumina, fused spinel, sintered spinel, fused spinel, fused magnesia, and sintered magnesia. The total amount of Al 2 O 3 + CaO is 99 to 100% by weight of the dispersant, 0.05 to 0.5% by weight of dispersant, 3 to 10% by weight of calcined alumina having an average particle size of 0.5 μm or less, and 99%. A high-purity alumina cement of not less than 1% by weight is added in a range not exceeding 1% by weight as the CaO amount, and the added moisture is not more than 4.5% by weight.
特許文献７では、耐火物を構成する骨材が、焼結アルミナ、電融アルミナ、ボーキサイト、ムライト、ロー石、シャモット、アルミナーマグネシアスピネル、炭化珪素、黒鉛、無定形炭素、ピッチ粉から選択される１種又は２種以上の原料からなることが開示されている。
この他にも取鍋などに施工する耐火物について特許文献８〜１４に示すものがある。
In Patent Document 7, the aggregate constituting the refractory is selected from sintered alumina, fused alumina, bauxite, mullite, rholite, chamotte, alumina-magnesia spinel, silicon carbide, graphite, amorphous carbon, and pitch powder. It consists of 1 type, or 2 or more types of raw materials.
In addition, there are those shown in Patent Documents 8 to 14 regarding refractories to be constructed in a ladle or the like.
特許文献１〜５では、精錬処理において、溶鋼の攪拌動力に関する指数、スラグの組成、溶鋼（鋼）の成分等を規定することによって介在物を制御し、高清浄度鋼を製造している。このような技術を用いると、バネなどの線材に用いる高清浄度鋼を製造することができるものの、近年、太陽電池用シリコンインゴット等の切断に用いられるソーワイヤなどの高性能な線材を製造することは難しいのが実情である。 In patent documents 1-5, in a refining process, inclusions are controlled by prescribing an index relating to stirring power of molten steel, a composition of slag, components of molten steel (steel), and the like, and high cleanliness steel is manufactured. Using such a technique, although it is possible to produce high cleanliness steel for use in wire rods such as springs, in recent years, it is possible to produce high performance wire rods such as saw wires used for cutting silicon ingots for solar cells, etc. Is difficult.
さて、上述した特許文献１〜５に示すように、精錬処理では、溶鋼の攪拌動力に関する指数、スラグの組成、溶鋼（鋼）の成分等の精錬条件を規定して溶鋼の介在物を制御することが考えられる。しかしながら、特許文献６〜１４に示されるように、耐火物について様々な技術が開発されているが、いずれの技術も単に耐火物の耐食性を向上さて寿命を長くする技術であり、精錬処理と連動して耐火物によって精錬処理後の溶鋼内に生成する介在物を制御するような技術ではない。 Now, as shown in Patent Documents 1 to 5 described above, in the refining process, the index related to the stirring power of the molten steel, the composition of the slag, the refining conditions such as the components of the molten steel (steel), etc. are defined to control the inclusions in the molten steel. It is possible. However, as shown in Patent Documents 6 to 14, various technologies have been developed for refractories, but all of these technologies are technologies that simply improve the corrosion resistance of the refractories and prolong the service life. Thus, it is not a technique for controlling inclusions generated in the molten steel after the refining treatment by the refractory.
そこで、本発明では、取鍋に施工する耐火物と精錬処理における条件との両面を考慮することにより介在物の生成を抑えて、高強度なソーワイヤを製造可能なソーワイヤ用鋼の製造方法を提供することを目的とする提供することを目的とする。 In view of this, the present invention provides a method for producing steel for saw wire capable of producing high-strength saw wire by suppressing the formation of inclusions by considering both the refractory to be applied to the ladle and the conditions in the refining process. The purpose is to provide.
前記目的を達成するために、本発明は、次の手段を講じた。
本発明の技術的手段は、取鍋にて溶鋼の精錬処理を行うことでソーワイヤ用鋼を製造するに際し、前記精錬処理に使用する取鍋に施工する耐火物に関し、当該耐火物の原料は、１ｍｍ以上のアルミナ粒子からなる粗骨材と、１ｍｍ未満のアルミナ粒子からなる微細骨材とを有しており、前記粗骨材に関し、その質量割合は、耐火物の原料の全量の４０％以上６０％以下とし、結晶径が１００μｍ以下である粗骨材の体積割合は粗骨材の全体積の３％以下とし、前記微細骨材に関し、結晶径が２０〜６０μｍである微細骨材の体積割合は微細骨材の全体積の５％以下とし、結晶径が１０μｍ以下である微細骨材の体積割合は微細骨材の全体積の４０％以上としており、前記取鍋での精錬処理に関し、ソーワイヤ用鋼を精錬する処理の１つ前に実施する精錬処理では、使用するスラグの組成を、Ｃ／Ｓ＝０．５〜１．２、Ａｌ２Ｏ３＝５〜１５質量％、ＭｇＯ＝２〜１５質量％とし、前記スラグの原単位を５〜１５ｋｇ／ｔｏｎとし、溶鋼の攪拌量を６５〜８５ｋＪ／ｔｏｎとすると共に、[sol．Al]を８ppm以下とし、ソーワイヤ用鋼を精錬する処理では、使用するスラグの組成を、Ｃ／Ｓ＝０．５〜１．２、Ａｌ２Ｏ３＝５〜１５質量％、ＭｇＯ＝２〜１５質量％とし、前記スラグの原単位を５〜１５ｋｇ／ｔｏｎとし、溶鋼の攪拌量を４０〜６０ｋＪ／ｔｏｎとすると共に、[sol．Al]を２ppm以下としていることを特徴とする。
In order to achieve the above object, the present invention has taken the following measures.
The technical means of the present invention relates to a refractory to be applied to a ladle used for the refining process when producing steel for saw wire by refining molten steel in a ladle, and the raw material of the refractory is: It has a coarse aggregate made of alumina particles of 1 mm or more and a fine aggregate made of alumina particles of less than 1 mm, and the mass ratio of the coarse aggregate is 40% or more of the total amount of refractory raw materials The volume ratio of the coarse aggregate having a crystal diameter of 60 μm or less is 3% or less of the total volume of the coarse aggregate, and the volume of the fine aggregate having a crystal diameter of 20 to 60 μm with respect to the fine aggregate. The ratio is 5% or less of the total volume of the fine aggregate, and the volume ratio of the fine aggregate having a crystal diameter of 10 μm or less is 40% or more of the total volume of the fine aggregate. Performed one step before refining saw wire steel That in refining process, the composition of the slag to be used, C / S = 0.5~1.2, Al 2 O 3 = 5~15 wt%, MgO = and 2 to 15 wt%, the basic unit of the slag 5 to 15 kg / ton, the stirring amount of molten steel is 65 to 85 kJ / ton, and [sol. In the process of refining steel for saw wire with Al] being 8 ppm or less, the composition of the slag used is C / S = 0.5 to 1.2, Al 2 O 3 = 5 to 15% by mass, MgO = 2 to 2 15 mass%, the basic unit of the slag is 5 to 15 kg / ton, the stirring amount of the molten steel is 40 to 60 kJ / ton, and [sol. Al] is 2 ppm or less.
本発明によれば、高強度なソーワイヤを製造可能なソーワイヤ用鋼を溶製することができる。特に、溶鋼中に含まれるアルミナ介在物を低減することができるため、製造されたソーワイヤは、伸線時における断線回数が非常に少ないものとなる。 According to the present invention, steel for saw wire capable of producing a high strength saw wire can be melted. In particular, since the alumina inclusions contained in the molten steel can be reduced, the manufactured saw wire has a very small number of breaks during wire drawing.
以下、本発明の実施の形態を図面に基づき説明する。
図１は、ソーワイヤ用の鋼を精錬処理する手順を示したものである。ソーワイヤとは、シリコン太陽電池、半導体シリコンウェハなどを精密に切断加工するための切断刃として使われるスチール鋼材のことである。以降、説明の便宜上、ソーワイヤを製造するための鋼のことをソーワイヤ鋼という。
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a procedure for refining saw wire steel. Saw wire is a steel material used as a cutting blade for precisely cutting silicon solar cells, semiconductor silicon wafers, and the like. Hereinafter, for convenience of explanation, steel for manufacturing saw wire is referred to as saw wire steel.
図１に示すように、ソーワイヤ鋼を製造するに際しては、まず、ソーワイヤ鋼を溶製する際に用いる取鍋１に対して所定の耐火物２を施工する（耐火物施工）。そして、ソーワイヤ鋼を溶製する１つ前の精錬処理（前精錬処理）では、取鍋１を用いてソーワイヤ鋼とは別の鋼を溶製した後、前精錬処理後に同一の取鍋１で本精錬処理にてソーワイヤ鋼を溶製する。 As shown in FIG. 1, when manufacturing saw wire steel, first, a predetermined refractory 2 is applied to a ladle 1 used when melting saw wire steel (refractory construction). In the previous refining process (pre-refining process) in which the saw wire steel is melted, a steel other than the saw wire steel is melted using the ladle 1 and then the same ladle 1 after the pre-smelting process. Saw wire steel is melted by this refining process.
図２は、ソーワイヤ鋼を溶製する取鍋の断面構造を示したものである。まず、取鍋の構造について説明する。なお、取鍋は図２に示したものに限定されない。
取鍋１は、本体を構成する上部が開放となった円柱状の鉄皮３を備えている。この鉄皮３の稼働面側（溶鋼が入る側）には、定形の耐火物２で構成された第１パーマ煉瓦２ａが施工されている。鉄皮３内において、鉄皮３の胴部４に対応する部分には、第１パーマ煉瓦２ａに続き、さらに当該第１パーマ煉瓦２ａの内側に２層目となる第２パーマ煉瓦２ｂが施工されている。また、鉄皮３内において、鉄皮３の底部６及び鉄皮３の胴部４に対応する部分には、不定形の耐火物２であるキャスタブル２ｃが施工されている。
FIG. 2 shows a cross-sectional structure of a ladle for melting saw wire steel. First, the structure of the ladle will be described. The ladle is not limited to that shown in FIG.
The ladle 1 includes a columnar iron skin 3 whose upper part constituting the main body is open. A first permanent brick 2a composed of a regular refractory 2 is applied to the working surface side (the side into which molten steel enters) of the iron shell 3. In the iron shell 3, the second permanent brick 2b, which is the second layer, is constructed inside the first permanent brick 2a, following the first permanent brick 2a, in the portion corresponding to the body 4 of the iron shell 3. Has been. In addition, castable 2 c, which is an irregular refractory 2, is applied to portions corresponding to the bottom portion 6 of the iron skin 3 and the body portion 4 of the iron skin 3 in the iron skin 3.
詳しくは、鉄皮３の底部６に対応する第２パーマ煉瓦２ｂの稼働面にキャスタブル２ｃが流し込み施工されている。また、鉄皮３の胴部４に対応する部分であって、底部６から上下方向中途部分までの溶鋼が接する部分にもキャスタブル２ｃが施工されている。言い換えれば、鉄皮３の胴部４に施工した第２パーマ煉瓦２ｂの稼働面うち、スラグラインを除く稼働面側には、キャスタブル２ｃが施工されている。 Specifically, the castable 2c is poured into the working surface of the second permanent brick 2b corresponding to the bottom portion 6 of the iron skin 3. Further, the castable 2c is also applied to a portion corresponding to the body portion 4 of the iron shell 3 and in contact with the molten steel from the bottom portion 6 to the middle portion in the vertical direction. In other words, the castable 2c is constructed on the working surface side excluding the slag line among the working surfaces of the second permanent brick 2b constructed on the body 4 of the iron skin 3.
キャスタブル２ｃから上部側であって、スラグラインに対応する部分には、定形の耐火物９であるマグカーボン（ＭｇＯ−Ｃ耐火物）が施工されている。なお、取鍋１の敷部６には、溶鋼を外部へ出鋼（排出）するための排出口８が設けられている。
さて、取鍋２の内部を見たとき、取鍋２の敷部６に施工されたキャスタブル２ｃや取鍋２の胴部４に施工されたキャスタブル２ｃは、運搬時や精錬処理時などに溶鋼が頻繁に接する部分（メタルライン）である。本発明では、溶鋼が頻繁に接するメタルラインの耐火物（キャスタブル２ｃ）を、後述するような耐火物（アルミナ系不定形耐火物）にすることによって、精錬処理時に耐火物から溶鋼に混入する硬質のアルミナ介在物を低減することとしている。
Magcarbon (MgO—C refractory), which is a regular refractory 9, is applied to the upper portion from the castable 2 c and corresponding to the slag line. The ladle portion 6 of the ladle 1 is provided with a discharge port 8 for discharging the molten steel to the outside (discharge).
Now, when the inside of the ladle 2 is seen, the castable 2c constructed in the laying part 6 of the ladle 2 and the castable 2c constructed in the trunk 4 of the ladle 2 are molten steel during transportation or refining treatment. Is a part (metal line) that frequently touches. In the present invention, the refractory (castable 2c) of the metal line with which the molten steel is frequently in contact is made a refractory (alumina-based amorphous refractory) as described later, so that the hard material mixed into the molten steel from the refractory during refining treatment. The alumina inclusions are reduced.
メタルラインに用いる耐火物は、主にアルミナ粒子が含有された原料で構成されたもので、アルミナ系不定形耐火物とされている。アルミナ系不定形耐火物の成分は、例えば、Ａｌ２Ｏ３が９０〜９５質量％、ＭｇＯが５〜８質量％、その他はＳｉＯ２などである。
図３は、アルミナ系不定形耐火物の原料を模したものである。
図３に示すように、アルミナ系不定形耐火物の主原料は、まず、１ｍｍ以上の粒子によって構成された粗骨材１０と、１ｍｍ未満の粒子によって構成された微細骨材１１とに分けられる。詳しくは、粗骨材１０は多結晶体であって１ｍｍ以上のアルミナ粒子で構成されたもので、微細骨材１１はほぼ単結晶であって１ｍｍ未満のアルミナ粒子によって構成されたものである。粗骨材１０と微細骨材１１とは、顕微鏡などを用いた観察により容易に選別することができる。特に、粗骨材１０については、特開平０７−３００３７０号公報や特開２００２−２３４７７６号公報に開示されているものであり、当業者であれば容
易に認識することができる。
The refractory used for the metal line is mainly composed of a raw material containing alumina particles, and is an alumina-based amorphous refractory. The components of the alumina-based amorphous refractory include, for example, Al 2 O 3 of 90 to 95% by mass, MgO of 5 to 8% by mass, and other components such as SiO 2 .
FIG. 3 imitates the raw material of the alumina-based amorphous refractory.
As shown in FIG. 3, the main raw material of the alumina-based amorphous refractory is first divided into a coarse aggregate 10 composed of particles of 1 mm or more and a fine aggregate 11 composed of particles of less than 1 mm. . Specifically, the coarse aggregate 10 is a polycrystal and is composed of alumina particles of 1 mm or more, and the fine aggregate 11 is substantially single crystal and is composed of alumina particles of less than 1 mm. The coarse aggregate 10 and the fine aggregate 11 can be easily selected by observation using a microscope or the like. In particular, the coarse aggregate 10 is disclosed in Japanese Patent Application Laid-Open Nos. 07-300370 and 2002-234776, and can be easily recognized by those skilled in the art.
粗骨材１０の質量割合は主原料の合計（全量）の４０％以上６０％以下としている。粗骨材１０は、主に耐火物の亀裂の伝搬を抑制する役割があり、亀裂の伝搬を抑制する観点からすれば、主原料に対する割合は多い方がよい。しかしながら、粗骨材１０が主原料の全量に対して６０質量％超えると、粗骨材１０は他の材料（例えば、微細骨材１１）に対して大きいため、粗骨材１０と微細骨材１１とを合わせたときの耐火物（全量）の充填率を見たとき、充填率が下がり空隙の部分が多くなるため、耐久性が減少する。一方、粗骨材１０が主原料の全量に対して４０質量％未満になると、十分に亀裂の伝搬を抑制することができない。このようなことから、上述したように、粗骨材１０の重量割合は主原料の全量の４０％以上６０％以下にする必要がある。 The mass ratio of the coarse aggregate 10 is 40% or more and 60% or less of the total (total amount) of the main raw materials. The coarse aggregate 10 mainly has a role of suppressing the propagation of cracks in the refractory. From the viewpoint of suppressing the propagation of cracks, it is better that the ratio of the coarse aggregate 10 to the main raw material is large. However, when the coarse aggregate 10 exceeds 60% by mass with respect to the total amount of the main raw material, the coarse aggregate 10 is larger than the other materials (for example, the fine aggregate 11). When the filling rate of the refractory (total amount) when combined with 11 is seen, the filling rate decreases and the number of voids increases, so the durability decreases. On the other hand, if the coarse aggregate 10 is less than 40% by mass with respect to the total amount of the main raw material, the propagation of cracks cannot be sufficiently suppressed. For this reason, as described above, the weight ratio of the coarse aggregate 10 needs to be 40% or more and 60% or less of the total amount of the main raw material.
さて、取鍋１による精錬処理中に粗骨材１０が溶鋼へ混入し、粗骨材１０を構成する粒子（結晶）の分解が起きた場合、図２（ｂ）に示すように、粗骨材１０を構成する結晶（結晶径）１２が大きいと、分解した結晶１２が溶鋼中を浮上してスラグ等に吸着するため、分解した結晶１２は溶鋼から除去することができる。一方、図２（ａ）に示すように、粗骨材１０を構成する結晶１２が小さいと、溶鋼中を浮上することが難しいため分解した結晶１２を除去することが難しくなる。 Now, when the coarse aggregate 10 is mixed into the molten steel during the refining process by the ladle 1 and the particles (crystals) constituting the coarse aggregate 10 are decomposed, as shown in FIG. If the crystal (crystal diameter) 12 constituting the material 10 is large, the decomposed crystal 12 floats in the molten steel and is adsorbed to slag and the like, so that the decomposed crystal 12 can be removed from the molten steel. On the other hand, as shown in FIG. 2 (a), if the crystal 12 constituting the coarse aggregate 10 is small, it is difficult to float in the molten steel, so it becomes difficult to remove the decomposed crystal 12.
そこで、本発明では、粗骨材１０に関して、結晶径が１００μｍ以下の小さい粗骨材１０の体積割合は、粗骨材（全ての粗骨材）１０の全体積の３％以下として少なめとしている。言い換えれば、結晶径が１００μｍ超の粗骨材１０は、粗骨材の全体積の９７体積％超とし、精錬処理などによって結晶が分解しても除去しやすいようにしている。
微細骨材１１は、粗骨材１０と合わせたとき、耐火物の充填率を上昇させ、空隙を少なくして溶鋼の浸潤を抑制して耐火物の耐久性を向上させる役割があり、粗骨材１０とはバランス良く配合される。
Therefore, in the present invention, with respect to the coarse aggregate 10, the volume ratio of the small coarse aggregate 10 having a crystal diameter of 100 μm or less is set to be 3% or less of the total volume of the coarse aggregate (all coarse aggregates) 10 and is small. . In other words, the coarse aggregate 10 having a crystal diameter of more than 100 μm is more than 97% by volume of the total volume of the coarse aggregate so that it can be easily removed even if the crystal is decomposed by a refining process or the like.
When the fine aggregate 11 is combined with the coarse aggregate 10, the fine aggregate 11 has a role of increasing the filling rate of the refractory, reducing the voids and suppressing the infiltration of the molten steel, and improving the durability of the refractory. The material 10 is blended with a good balance.
さて、ソーワイヤ鋼では、アルミナ介在物が溶鋼中に残ると線材の伸線時に断線を発生させる原因となることから、取鍋の精錬処理では出来る限りアルミナ介在物を低減することが必要である。
様々な実験等の検証の結果、結晶径が２０〜６０μｍである微細骨材１１が多く含まれるものを耐火物の材料とし、この耐火物を取鍋に施工して当該取鍋で精錬処理を行った場合、微細骨材１１による影響でアルミナ介在物が生成され、ソーワイヤ鋼でソーワイヤを製造したときに、ソーワイヤの伸線時における断線回数に大きな影響を与えることが分かった。本発明では、取鍋に施工する耐火物（メタルラインに施工する耐火物）の材料として微細骨材１１を使用する場合、結晶径が２０〜６０μｍとなる微細骨材１１の体積割合を、粗骨材１０の全体積の３％以下とし、出来る限り少なくしている。
Now, in saw wire steel, if alumina inclusions remain in the molten steel, it may cause disconnection when the wire is drawn, so it is necessary to reduce the alumina inclusions as much as possible in the ladle refining treatment.
As a result of verification of various experiments, etc., a material containing a large amount of fine aggregate 11 having a crystal diameter of 20 to 60 μm is used as a refractory material. When it did, it turned out that the alumina inclusion is produced | generated by the influence by the fine aggregate 11, and when a saw wire is manufactured with saw wire steel, it has big influence on the frequency | count of disconnection at the time of wire drawing of a saw wire. In this invention, when using the fine aggregate 11 as a refractory material (refractory material applied to a metal line) applied to a ladle, the volume ratio of the fine aggregate 11 having a crystal diameter of 20 to 60 μm is roughly determined. It is set to 3% or less of the total volume of the aggregate 10, and is reduced as much as possible.
微細骨材１１において、結晶径が２０〜６０μｍのものはソーワイヤの断線回数の増加に悪影響を与えてしまう可能性があるものの、これより小さく、結晶径が１０μｍ以下のものは、ソーワイヤによる断線回数に悪影響を与えず、耐火物の充填率などに寄与することが様々な実験等により検知した。このようなことから、本発明では、微細骨材１１に関し、結晶径が１０μｍ以下である微細骨材の体積割合は微細骨材の全体積の４０％以上としている。 The fine aggregate 11 having a crystal diameter of 20 to 60 μm may adversely affect the increase in the number of disconnections of the saw wire, but is smaller than this and the crystal diameter of 10 μm or less is the number of disconnections due to the saw wire. It has been detected by various experiments that it contributes to the filling ratio of refractories without adversely affecting the refractory. For this reason, in the present invention, with respect to the fine aggregate 11, the volume ratio of the fine aggregate having a crystal diameter of 10 μm or less is set to 40% or more of the total volume of the fine aggregate.
図４は、メタルラインに施工する耐火物に関して、粗骨材１０と微細骨材１１とについてまとめたものである。図４に示すように、耐火物を構成する主原料のうち、粗骨材１０の重量割合は４０％以上６０％以下とし、残りを微細骨材１１としている。また、全粗骨材のうち、１００μｍ以下の結晶径のものを全体の３体積％以下とし、１００μｍを超える結晶径のものを全体の９７体積％超としている。さらに、全微細骨材１１のうち、２０〜６０μｍの結晶径のものを全体の５体積％以下とし、１０μｍ以下の結晶径のものを４０体積％以上としている。 FIG. 4 summarizes the coarse aggregate 10 and the fine aggregate 11 regarding the refractories to be constructed on the metal line. As shown in FIG. 4, among the main raw materials constituting the refractory, the weight ratio of the coarse aggregate 10 is 40% or more and 60% or less, and the remainder is the fine aggregate 11. Further, among the total coarse aggregate, those having a crystal diameter of 100 μm or less are set to 3% by volume or less, and those having a crystal diameter exceeding 100 μm are set to exceed 97% by volume. Further, among the total fine aggregates 11, those having a crystal diameter of 20 to 60 μm are 5% by volume or less of the total aggregate, and those having a crystal diameter of 10 μm or less are 40% by volume or more.
このように、ソーワイヤ鋼を製造するに際しては、取鍋に施工する耐火物のうち、主に溶鋼が接するメタルラインに施工する耐火物を上述した材料で構成することとしている。
次に、ソーワイヤ鋼を溶製する精錬処理について説明する。
ソーワイヤ鋼を溶製する前に行う前精錬処理では、ソーワイヤ鋼とは別の鋼を溶製する
ことによって、前精錬処理のスラグ等によってメタルラインに施工したアルミナ系不定形耐火物の稼働面を改質し、次に行うソーワイヤ鋼の溶製を行う当該精錬処理時に耐火物からアルミナ介在物の混入を抑制できるようにしている。
Thus, when manufacturing saw wire steel, among the refractories to be constructed on the ladle, the refractories to be constructed on the metal line mainly in contact with the molten steel are composed of the materials described above.
Next, a refining process for melting saw wire steel will be described.
In the pre-refining process that is performed before melting the saw wire steel, the working surface of the alumina-based amorphous refractory applied to the metal line by the slag etc. of the pre-refining process is obtained by melting a steel other than the saw wire steel. It is made possible to suppress the inclusion of alumina inclusions from the refractory during the refining process for reforming and subsequent saw wire steel melting.
詳しくは、図１に示すように、前精錬処理では、上述した耐火物２（２ｃ）を施工した取鍋１に、転炉などで脱炭処理の終了した溶鋼２０を装入し、この取鍋１を二次精錬設備２１に移動させる。二次精錬設備２１がＬＦ装置である場合、電極式加熱装置（電極アーク加熱装置）２２を用いて、溶鋼２０の温度を所定温度まで上昇させ、底吹き用プラグ２３から不活性ガスを吹き込んで溶鋼２０を攪拌すると共に、フラックス等の精錬剤を供給装置から供給することによって、Ｓｉキルド鋼を溶製する。即ち、二次精錬設備２１を用いて[sol．Al]が８ppm以下となるＳｉキルド鋼を溶製する。 Specifically, as shown in FIG. 1, in the pre-refining process, the ladle 1 in which the refractory 2 (2c) described above is constructed is charged with the molten steel 20 that has been decarburized by a converter or the like, and this removal is performed. The pan 1 is moved to the secondary refining equipment 21. When the secondary refining equipment 21 is an LF apparatus, the temperature of the molten steel 20 is raised to a predetermined temperature using an electrode type heating apparatus (electrode arc heating apparatus) 22 and an inert gas is blown from a bottom blowing plug 23. While stirring molten steel 20, Si killed steel is melted by supplying a refining agent such as flux from a supply device. That is, using the secondary refining equipment 21 [sol. Si killed steel with Al] of 8 ppm or less is melted.
[sol．Al]が８ppmを超えた状態で前精錬処理を行ってしまうと、ソーワイヤ鋼を溶製する当該精錬処理へのアルミナ系介在物の持ち込み量が増加するため、前精錬処理では[sol．Al]を８ppm以下にしている。また、前精錬処理におけるスラグ組成を、Ｃ／Ｓ（塩基度）＝０．５〜１．２、Ａｌ２Ｏ３＝５〜１５質量％、ＭｇＯ＝２〜１５質量％としている。 [sol. If the pre-refining treatment is performed in a state where Al exceeds 8 ppm, the amount of alumina inclusions brought into the refining treatment for melting saw wire steel increases. Al] is 8 ppm or less. Moreover, the slag composition in the pre-refining process is C / S (basicity) = 0.5 to 1.2, Al 2 O 3 = 5 to 15% by mass, and MgO = 2 to 15% by mass.
前精錬処理においてスラグの塩基度（Ｃ／Ｓ）が高いと耐火物との反応が進み、アルミナ系不定形耐火物の稼働面の改質を進めるものの、塩基度が１．２を超えて高すぎると、反応が速すぎて構造スポーリング、即ち、耐火物の剥離が発生してしまう。一方、スラグの塩基度が０．５未満である場合、スラグと耐火物との反応が遅く、耐火物の改質が十分に進まない。このようなことから、塩基度は０．５〜１．２にする必要がある。 If the basicity (C / S) of the slag is high in the pre-refining process, the reaction with the refractory proceeds and the working surface of the alumina-based amorphous refractory is improved, but the basicity exceeds 1.2. If it is too high, the reaction will be too fast and structural spalling, that is, refractory peeling will occur. On the other hand, when the basicity of the slag is less than 0.5, the reaction between the slag and the refractory is slow, and the modification of the refractory does not proceed sufficiently. For this reason, the basicity needs to be 0.5 to 1.2.
また、前精錬処理においてスラグのＡｌ２Ｏ３が少ないと、耐火物との反応が進み、アルミナ系不定形耐火物の稼働面の改質が進むものの、Ａｌ２Ｏ３が５質量％未満であると、耐火物の剥離が発生してしまう。一方、スラグのＡｌ２Ｏ３が１５質量％を超えてしまうと、スラグと耐火物との反応が遅く、耐火物の改質が十分に進まないばかりか、アルミナ介在物が増加してしまう可能性もある。このようなことから、スラグ中のＡｌ２Ｏ３は５〜１５質量％にする必要がある。 In addition, when the amount of Al 2 O 3 in the slag is small in the pre-smelting treatment, the reaction with the refractory proceeds and the working surface of the alumina-based amorphous refractory progresses. However, Al 2 O 3 is less than 5% by mass. If it exists, the refractory will peel off. On the other hand, if the Al 2 O 3 content of the slag exceeds 15% by mass, the reaction between the slag and the refractory is slow, and the refractory reforming does not proceed sufficiently, and alumina inclusions may increase. There is also sex. For this reason, Al 2 O 3 in the slag needs to be 5 to 15% by mass.
前精錬処理においてスラグのＭｇＯが少ないと、スラグラインの耐火物の溶損が進み当該スラグラインの耐火物を保護することができないことから、ＭｇＯを２質量％以上にすることがある。一方、スラグのＭｇＯが１５質量％を超えてしまうと、スラグラインの耐火物の保護はできるものの、スラグの粘度が上がり過ぎ、スラグによる耐火物の改質が遅くなる。このようなことから、スラグ中のＭｇＯは２〜１５質量％にする必要がある。 If MgO in the slag is low in the pre-smelting treatment, the refractory in the slag line is melted and the refractory in the slag line cannot be protected, so MgO may be 2% by mass or more. On the other hand, if MgO in the slag exceeds 15% by mass, the refractory of the slag line can be protected, but the viscosity of the slag increases too much, and the refractory reforming by the slag becomes slow. For this reason, MgO in the slag needs to be 2 to 15% by mass.
上述したように前精錬処理ではスラグと耐火物との反応によってメタルラインに施工したアルミナ系不定形耐火物の稼働面を改質することとしているが、改質のためには、スラグ量も重要である。スラグ量が少なくスラグの原単位が５ｋｇ／ｔｏｎの場合、耐火物を被覆するためのスラグ量が少なく十分に耐火物の改質が進まない。一方、スラグ量が多くスラグの原単位が１５ｋｇ／ｔｏｎを超えると耐火物の改質はできるものの、スラグの滓化に非常に長い時間を要したり、必要以上にスラグが多いため精錬処理が素早く進まない可能性がある。このようなことから、スラグ原単位は５〜１５ｋｇ／ｔｏｎとする必要がある。 As described above, in the pre-smelting treatment, the working surface of the alumina-based amorphous refractory applied to the metal line is modified by the reaction between the slag and the refractory, but the amount of slag is also important for the modification. It is. When the amount of slag is small and the basic unit of slag is 5 kg / ton, the amount of slag for covering the refractory is small and the refractory reforming does not proceed sufficiently. On the other hand, when the amount of slag is large and the basic unit of slag exceeds 15 kg / ton, the refractory can be reformed, but it takes a very long time to hatch the slag, or the refining treatment is performed because there is more slag than necessary. There is a possibility of not progressing quickly. For these reasons, the slag basic unit needs to be 5 to 15 kg / ton.
また、耐火物の改質を進めるためには、スラグ量だけでなく、溶鋼を適度に攪拌してスラグと耐火物との反応が進みやすくする必要がある。溶鋼の攪拌量が小さく６５ＫＪ／ｔｏｎ未満である場合、スラグと耐火物との反応性が低下して耐火物の改質が不足すると共に耐火物の稼働面に付着した付着物の洗浄力が低下する。一方、溶鋼の攪拌量が大きく８５ｋＪ／ｔｏｎを超える場合、耐火物の改質が進むものの、構造スポーリングが発生する。このようなことから、溶鋼の攪拌量は６５〜８５ｋＪ／ｔｏｎにする必要がある。 Moreover, in order to advance the reforming of the refractory, it is necessary to facilitate not only the amount of slag but also the molten steel to be appropriately stirred so that the reaction between the slag and the refractory proceeds. When the amount of stirring of the molten steel is small and less than 65 KJ / ton, the reactivity between the slag and the refractory is reduced, the refractory is insufficiently modified, and the detergency of the deposits adhering to the working surface of the refractory is reduced. To do. On the other hand, when the amount of stirring of the molten steel is large and exceeds 85 kJ / ton, structural spalling occurs although refractory reforming proceeds. For this reason, the stirring amount of the molten steel needs to be 65 to 85 kJ / ton.
なお、溶鋼の攪拌量は、攪拌動力密度に攪拌時間を掛け合わせることにより求めることができる（攪拌量＝攪拌動力密度×攪拌時間）。攪拌動力密度は、特開２００８−２６１０１４号公報に開示されているものと同じ式（１）で算出することができる。 The amount of stirring of the molten steel can be determined by multiplying the stirring power density by the stirring time (stirring amount = stirring power density × stirring time). The stirring power density can be calculated by the same formula (1) as that disclosed in Japanese Patent Application Laid-Open No. 2008-261014.
なお、前精錬処理は、上述したＬＦ装置による精錬に限定されず、ＣＡＳ装置による精
錬であってもよい。また、前精錬処理において、不活性ガスの吹き込みは、上方から上吹きランスを溶鋼内に挿入して上吹きランスにて不活性ガスを吹き込むものであってもよい。
上述したように、取鍋を用いて前精錬処理が終了し、当該取鍋内のアルミナ系不定形耐火物の稼働面を改質した後は、同一の取鍋を用いてソーワイヤ鋼の溶製を行う。ソーワイヤ鋼の溶製を行う精錬処理を、本精錬処理という。
Note that the pre-refining process is not limited to the refining by the LF apparatus described above, but may be refining by the CAS apparatus. In the pre-smelting treatment, the inert gas may be blown by inserting an upper blowing lance into the molten steel from above and blowing the inert gas with the upper blowing lance.
As described above, after the pre-smelting process is completed using the ladle and the working surface of the alumina-based amorphous refractory in the ladle is modified, the melting of saw wire steel is performed using the same ladle. I do. The refining process in which saw wire steel is melted is called the present refining process.
本精錬処理では、前精錬処理と同様にＬＦ精錬装置やＣＡＳ精錬装置などを用いて溶鋼の精錬を行う。
詳しくは、図１に示すように、本精錬処理では、前精錬処理が終了した取鍋１に溶鋼２０を装入した後、二次精錬設備２１がＬＦ装置である場合は電極式加熱装置２２を用いて、取鍋１内の溶鋼２０の温度を所定温度まで上昇させ、底吹き用プラグ２３から不活性ガスを吹き込んで溶鋼２０を攪拌すると共に、フラックス等の精錬剤を供給装置から供給することによって、ソーワイヤ鋼を溶製する。本精錬処理では、前精錬処理よりも溶鋼に含まれるＡｌの量を少なくすることとしており、[sol．Al]が２ppm以下となるように精錬処理を行っている。
In this refining process, molten steel is refined using an LF refining apparatus, a CAS refining apparatus, or the like, as in the pre-refining process.
Specifically, as shown in FIG. 1, in this refining process, after the molten steel 20 is charged into the ladle 1 in which the pre-refining process has been completed, when the secondary refining equipment 21 is an LF apparatus, an electrode-type heating apparatus 22 , The temperature of the molten steel 20 in the ladle 1 is raised to a predetermined temperature, an inert gas is blown from the bottom blowing plug 23 to stir the molten steel 20, and a refining agent such as flux is supplied from a supply device. As a result, saw wire steel is melted. In this refining process, the amount of Al contained in the molten steel is reduced compared to the pre-refining process, [sol. Refining treatment is performed so that Al] is 2 ppm or less.
[sol．Al]が２ppmを超えた状態で本精錬処理を行ってしまうと、溶鋼中のアルミナ系介在物が増加するため、本精錬処理では[sol．Al]を２ppm以下にしている。
また、本精錬処理では、前精錬処理と同様に、スラグ組成をＣ／Ｓ（塩基度）＝０．５〜１．２、Ａｌ２Ｏ３＝５〜１５質量％、ＭｇＯ＝２〜１５質量％とし、スラグ原単位を５〜１５ｋｇ／ｔｏｎとしている。
[sol. If this refining process is performed in a state where Al exceeds 2 ppm, alumina inclusions in the molten steel increase, so that in this refining process, [sol. Al] is 2 ppm or less.
Further, in the present refining process, as before refining treatment, the slag composition C / S (basicity) = 0.5~1.2, Al 2 O 3 = 5~15 wt%, MgO = 2 to 15 weight %, And the slag basic unit is 5 to 15 kg / ton.
本精錬処理では、前精錬処理と同じようにスラグによって耐火物の改質を進めるという耐火物の改質の観点と、溶鋼中の介在物の除去との観点から、スラグ組成及びスラグ原単位を設定していて、これらのスラグ組成及びスラグ原単位を満たすことによって、溶鋼中のアルミナ介在物を少なくできるようにしている。なお、スラグ組成及びスラグ原単位の範囲の説明は前精錬処理と同じであるため説明を省略する。 In this refining process, the slag composition and slag basic unit are determined from the viewpoint of refractory reforming, which promotes refractory reforming with slag as in the previous refining process, and the removal of inclusions in molten steel. By setting and satisfying these slag composition and slag basic unit, alumina inclusions in the molten steel can be reduced. In addition, since description of the range of a slag composition and a slag basic unit is the same as the pre-refining process, description is abbreviate | omitted.
さて、ソーワイヤ鋼を溶製するに際してスラグ組成やスラグ原単位を上述した条件にすることが必要であるが、これに加えて、溶鋼の攪拌量を制御（調整）することによって、最終的に溶鋼中に存在するアルミナ介在物を十分に少なくすることが必要である。特に、溶鋼の攪拌量の大きさは、スラグによって行われる耐火物の改質と、耐火物から溶鋼へのアルミナ介在物の原因となる物質の混入と、スラグによるアルミナ介在物の捕獲とに影響を与え、特に、本精錬処理の段階では適正に設定しなければならない。様々な検証の結果、本精錬処理の攪拌量の上下限値は前精錬処理に比べて小さくする必要があり、本精錬処理の溶鋼の攪拌量は４０〜６０ｋＪ／ｔｏｎにする必要がある。 Now, when melting saw wire steel, it is necessary to set the slag composition and slag basic unit to the above-mentioned conditions, but in addition to this, by controlling (adjusting) the amount of stirring of the molten steel, finally the molten steel It is necessary to sufficiently reduce the alumina inclusions present therein. In particular, the amount of stirring of the molten steel affects the refractory reforming performed by the slag, the inclusion of substances that cause alumina inclusions from the refractory to the molten steel, and the capture of the alumina inclusions by the slag. In particular, it must be set appropriately at the stage of the refining process. As a result of various verifications, the upper and lower limit values of the stirring amount of this refining process need to be smaller than those of the pre-refining process, and the stirring amount of the molten steel of this refining process needs to be 40-60 kJ / ton.
以上のように、本発明では、まず、メタルラインに上述した耐火物を施工したうえで、前精錬処理では耐火物の改質を行う精錬を行ったうえで、本精錬処理では耐火物の改質などを行いつつソーワイヤ鋼の溶製を行うこととしている。
図５は、１カ所の二次精錬ステーションにおける５つの取鍋（Ａ鍋、Ｂ鍋、Ｃ鍋、Ｄ鍋、Ｅ鍋）の移り変わりを示したものである。図５に示すように、二次精錬ステーションではＡ鍋から順にＥ鍋まで精錬処理を繰り返し行うとする。
As described above, according to the present invention, first, the above-described refractory is applied to the metal line, the refractory is reformed in the pre-refining process, and the refractory is modified in the present smelting process. Saw wire steel will be melted while maintaining quality.
FIG. 5 shows the transition of five ladles (A pan, B pan, C pan, D pan, E pan) at one secondary refining station. As shown in FIG. 5, in the secondary refining station, the refining process is repeated from the A pot to the E pot in order.
Ｂ鍋でソーワイヤ鋼を溶製する場合、まず、１チャージ目のＡ鍋による精錬処理が終了した後、２チャージ目でＢ鍋にて前精錬処理を行い。前精錬処理終了後はＢ鍋内を連続鋳造工程などに搬送し、溶鋼を払い出しする。溶鋼の払い出し後、再びＢ鍋を二次精錬ステーションに戻し、６チャージ目のＡ鍋による精錬処理が終了した後、７チャージ目でＢ鍋にて本精錬処理を行い、ソーワイヤ鋼を溶製する。 When smelting saw wire steel with the B pan, first, after the refining process with the A pot of the first charge is completed, the pre-refining process is performed with the B pot at the second charge. After the pre-smelting process is completed, the inside of the B pan is conveyed to a continuous casting process and the molten steel is dispensed. After the molten steel is dispensed, the B pan is returned to the secondary refining station, and after the refining process with the 6th charge A pan is completed, the final refining process is performed with the B pan at the 7th charge to melt the saw wire steel. .
ここで、Ｂ鍋を用いて連続してソーワイヤ鋼を溶製する場合は、図５に示すように、７チャージ目に続く１２チャージ目においてＢ鍋により本精錬処理を行うことが好ましい。即ち、同じ取鍋（この場合、Ｂ鍋）を用いてソーワイヤ鋼を連続して繰り返し溶製する場合は、１回目の本精錬処理を行う前に、当該本精錬処理を行う取鍋と同じ取鍋を用いて前精錬処理を少なくとも１回行っておき、その後、この取鍋にて本精錬処理を連続して行うことが好ましい。この場合は、「前精錬処理→本精錬処理→本精錬処理」の順となる。な
お、同じ取鍋を用いて前精錬処理と本精錬処理とを繰り返し行ってソーワイヤ鋼を溶製しても良い。この場合は、「前精錬処理→本精錬処理→前精錬処理→本精錬処理」の順となる。
Here, when continuously melting saw wire steel using the B pan, as shown in FIG. 5, it is preferable to perform the main refining process using the B pan at the 12th charge following the 7th charge. That is, when saw wire steel is continuously and repeatedly melted using the same ladle (in this case, B pan), the same ladle as the ladle performing the main refining process is performed before the first main refining process. It is preferable that the pre-smelting treatment is performed at least once using a pan, and then this refining treatment is continuously performed in this ladle. In this case, the order is “pre-refining process → main refining process → main refining process”. Note that the saw wire steel may be melted by repeatedly performing the pre-smelting process and the main refining process using the same ladle. In this case, the order is “pre-refining process → main refining process → pre-refining process → main refining process”.
表１〜５は、本発明のソーワイヤの製造方法を行った実施例と、本発明のソーワイヤの製造方法とは異なる方法を行った比較例とをまとめたものである。このうち、表５は、ソーワイヤ鋼を連続して繰り返し溶製する場合についてまとめたものである。 Tables 1 to 5 summarize examples in which the saw wire manufacturing method of the present invention was performed and comparative examples in which a method different from the saw wire manufacturing method of the present invention was performed. Of these, Table 5 summarizes the case where saw wire steel is continuously and repeatedly melted.
まず、実施例及び比較例の精錬処理について説明する。表１〜４の実施例及び比較例では、ソーワイヤ鋼を溶製する取鍋に対して当該取鍋のメタルラインに上述した耐火物を施工し、その後、取鍋に転炉からの溶鋼を払い出し、前精錬処理を行った後、さらに、同一の取鍋に対して再び転炉からの溶鋼を払い出し、本精錬処理を行った。本精錬処理後に連続鋳造装置にて当業者常法通りに１５０ｍｍのビレットを製造し、このビレットを線材圧延機にてφ６ｍｍの丸棒に加工後、１００μｍの極細線に伸線加工した。極細線の伸線時において、介在物が原因となる断線回数を計測した。断線回数の計測では、鋼材５トンごとの断線回数をカウントし、計約２５０トン（取鍋１杯分）の断線回数の平均と最大値及び最小値を求めた。 First, the refining process of an Example and a comparative example is demonstrated. In the examples and comparative examples in Tables 1 to 4, the above-mentioned refractory is applied to the metal line of the ladle for the ladle for melting saw wire steel, and then the molten steel from the converter is dispensed to the ladle. After the pre-smelting treatment, the molten steel from the converter was again dispensed to the same ladle and the refining treatment was performed. After this refining treatment, a billet of 150 mm was produced in a continuous casting apparatus as usual by those skilled in the art, and this billet was processed into a φ6 mm round bar by a wire rod rolling machine and then drawn into a 100 μm extra fine wire. The number of breaks caused by inclusions was measured when the extra fine wire was drawn. In the measurement of the number of breaks, the number of breaks for every 5 tons of steel was counted, and the average and maximum and minimum values of the number of breaks for a total of about 250 tons (one cup of ladle) were obtained.
表５の実施例及び比較例は、ソーワイヤ鋼を連続して繰り返し溶製した場合を示したもので、本精錬処理後に同一取鍋にて連続して本精錬処理を行ったものである。表中の「前ｃｈ実験」の欄は、同一取鍋に対して１つ前のチャージにおける実施例又は比較例の番号を示したものである。
転炉は、２５０ｔｏｎクラス（粗鋼トンが２５０ｔｏｎ）のものを用いた。取鍋のスラグラインの耐火物はマグカーボン（ＭｇＯ−Ｃ耐火物）とし、メタルラインに上述した耐火物を使用した。この耐火物の原料の粒度は、マイクロトラッキング装置にて測定を行った。耐火物の原料の結晶サイズ（粒度径）は、原料の断面を走査型電子顕微鏡（ＳＥＭ）にて観察して求めた。ＳＥＭによる観察面積は３ｃｍ２とした。鋼（鋼材）の成分は、Ｃ：０．８３〜０．８５質量％、Ｓｉ：０．１８〜０．１９質量％、Ｍｎ：０．４８〜０．５２質量％、Ｐ：０．００７〜０．０１質量％、Ｓ：０．００４〜０．００８質量％、Ａｌ：０．００１〜０．００２質量％とした。
The examples and comparative examples in Table 5 show the case where saw wire steel is continuously and repeatedly melted, and the main refining process is performed continuously in the same ladle after the main refining process. The column of “previous ch experiment” in the table indicates the number of the example or comparative example in the previous charge for the same ladle.
The converter used was a 250 ton class (crude steel ton is 250 ton). The refractory of the slag line of the ladle was magcarbon (MgO-C refractory), and the above-mentioned refractory was used for the metal line. The particle size of the refractory material was measured with a microtracking device. The crystal size (particle size) of the refractory material was determined by observing a cross section of the material with a scanning electron microscope (SEM). The observation area by SEM was 3 cm 2 . The components of steel (steel material) are: C: 0.83-0.85 mass%, Si: 0.18-0.19 mass%, Mn: 0.48-0.52 mass%, P: 0.007- 0.01 mass%, S: 0.004 to 0.008 mass%, Al: 0.001 to 0.002 mass%.
[sol.Al]の測定は、二次イオン質量分析計（ＳＩＭＳ）で行った。溶鋼温度は平均温度で１８２３Ｋとした。さらに、取鍋の温度を放射温度計などにより測定しながら管理することとし、取鍋のメタルラインの耐火物の温度を８００〜１０００℃の範囲とし、６０〜９０分間制御を行った。
実施例１〜２２では、粗骨材に関して、「粗骨材中、結晶径１００μｍ以下の体積割合」の欄に示すように、結晶径が１００μｍ以下のものは全粗骨材の３体積％以下であり、粗骨材の重量割合は主原料の４０％以上６０％以下である。また、実施例１〜２２では、微細骨材に関して、「骨材（２０〜６０μｍ）の体積割合」の欄に示すように、結晶径が２０〜６０μｍのものは全微細骨材の５体積％以下であり、「骨材（〜１０μｍの体積割合」の欄に示すように、結晶径が１０μｍ以下のものは４０体積％以上であった。
[sol.Al] was measured with a secondary ion mass spectrometer (SIMS). The molten steel temperature was 1823K as an average temperature. Furthermore, the temperature of the ladle was controlled while being measured with a radiation thermometer or the like, the temperature of the refractory on the metal line of the ladle was set in the range of 800 to 1000 ° C., and control was performed for 60 to 90 minutes.
In Examples 1 to 22, with respect to the coarse aggregate, as shown in the column “volume ratio of coarse aggregate with crystal diameter of 100 μm or less”, those with a crystal diameter of 100 μm or less are 3% by volume or less of the total coarse aggregate. The weight ratio of the coarse aggregate is 40% or more and 60% or less of the main raw material. Moreover, in Examples 1-22, regarding the fine aggregate, as shown in the column of “volume ratio of aggregate (20-60 μm)”, those having a crystal diameter of 20-60 μm are 5% by volume of the total fine aggregate. As shown in the column “Aggregate (Volume Ratio of 10 μm”), those having a crystal diameter of 10 μm or less were 40% by volume or more.
実施例１〜２２では、前精錬処理において、[sol．Al]を８ppm以下とし、スラグ組成を、Ｃ／Ｓ＝０．５〜１．２、Ａｌ２Ｏ３＝５〜１５質量％、ＭｇＯ＝２〜１５質量％とし、スラグ原単位を５〜１５ｋｇ／ｔｏｎとし、攪拌量を６５〜８５ｋＪ／ｔｏｎとしている。また、実施例１〜２２では、本精錬処理において、[sol．Al]を２ppm以下とし、スラグ組成を、Ｃ／Ｓ＝０．５〜１．２、Ａｌ２Ｏ３＝５〜１５質量％、ＭｇＯ＝２〜１５質量％とし、スラグ原単位を５〜１５ｋｇ／ｔｏｎとし、攪拌量を４０〜６０ｋＪ／ｔｏｎとしている。 In Examples 1-22, [sol. Al] is 8 ppm or less, the slag composition is C / S = 0.5 to 1.2, Al 2 O 3 = 5 to 15 mass%, MgO = 2 to 15 mass%, and the slag basic unit is 5 to 15 kg. / Ton, and the stirring amount is 65 to 85 kJ / ton. In Examples 1 to 22, in this refining process, [sol. Al] is 2 ppm or less, the slag composition is C / S = 0.5 to 1.2, Al 2 O 3 = 5 to 15 mass%, MgO = 2 to 15 mass%, and the slag basic unit is 5 to 15 kg. / Ton, and the amount of stirring is 40-60 kJ / ton.
実施例１〜２２では、ソーワイヤ鋼を製造したとしても、「ｍａｘ」の欄に示すように
、鋼材５ｔｏｎ当たりの断線回数が最大でも１回以下であり、「ａｖｅ」の欄に示すように、断線回数の平均値も１回以下とすることができた。
なお、実施例２３〜２８及び２０１〜２０５に示すように、本精錬処理を連続的に行ってソーワイヤ鋼を溶製した場合でも、２回目の本精錬処理の条件が上述した規定範囲であれば、鋼材５ｔｏｎ当たりの断線回数を最大でも１回以下にすることができ、断線回数の平均値も１回以下とすることができる。
In Examples 1 to 22, even when saw wire steel was manufactured, as shown in the column “max”, the number of disconnections per 5 ton of steel material was 1 or less at most, and as shown in the column “ave”, The average value of the number of disconnections was also reduced to 1 or less.
In addition, as shown in Examples 23 to 28 and 201 to 205, even when the main refining process is continuously performed and the saw wire steel is melted, the condition of the second main refining process is within the specified range described above. In addition, the number of disconnections per 5 ton of steel material can be set to 1 or less at the maximum, and the average value of the number of disconnections can be set to 1 or less.
一方、比較例２９〜３３では、粗骨材において、結晶径が１００μｍ以下のものは全粗骨材の３体積％を超えていたため、鋼材５ｔｏｎ当たりの断線回数が最大で３回以上となると共に断線回数の平均値も２回以上となる結果となった。比較例３４〜４１では、粗骨材の重量割合が全原料の４０％未満若しくは６０％を超えていたため、鋼材５ｔｏｎ当たりの断線回数が最大で３回以上となると共に断線回数の平均値も２回以上となる結果となった。また、比較例４２〜５４では、微細骨材に関して、結晶径が２０〜６０μｍのものが全微細骨材の５体積％を超えたり、結晶径が１０μｍ以下のものは４０体積％未満であったり、或いは、それ以外が上述した本発明の条件と外れていたため、実施例と比べて、鋼材５ｔｏｎ当たりの断線回数が大幅に増加した。 On the other hand, in Comparative Examples 29 to 33, the coarse aggregate having a crystal diameter of 100 μm or less exceeded 3% by volume of the total coarse aggregate, and therefore the number of disconnections per 5 ton of the steel material was 3 or more at the maximum. The average value of the number of disconnections was also 2 or more. In Comparative Examples 34 to 41, since the weight ratio of the coarse aggregate was less than 40% or more than 60% of the total raw material, the number of disconnections per 5 ton of steel was 3 or more at the maximum and the average value of the number of disconnections was 2 The result was more than once. In Comparative Examples 42 to 54, regarding the fine aggregate, those having a crystal diameter of 20 to 60 μm exceed 5% by volume of the total fine aggregate, and those having a crystal diameter of 10 μm or less are less than 40% by volume. Or, since the other conditions were not within the above-described conditions of the present invention, the number of disconnections per 5 ton of steel material was significantly increased as compared with the examples.
比較例５５〜８８は、前精錬処理における条件が本発明に規定した条件から外れたものである。比較例５５〜５７では[sol．Al]が８ppmよりも大きく、比較例５８〜６３ではスラグの塩基度が０．５より小さいと共に１．２より大きく、比較例６４〜６９ではスラグのＡｌ２Ｏ３が５質量％より小さいと共に１５質量％より大きく、比較例７０〜７５ではスラグのＭｇＯが２質量％小さいと共に１５質量％より大きい。 In Comparative Examples 55 to 88, the conditions in the pre-refining treatment deviate from the conditions defined in the present invention. In Comparative Examples 55 to 57, [sol. Al] is greater than 8 ppm, in Comparative Examples 58 to 63, the basicity of the slag is smaller than 0.5 and larger than 1.2, and in Comparative Examples 64 to 69, the Al 2 O 3 of the slag is smaller than 5% by mass. It is larger than 15% by mass, and in Comparative Examples 70 to 75, MgO of the slag is 2% by mass and larger than 15% by mass.
また、比較例７６〜８１ではスラグ原単位が５ｋｇ／ｔｏｎより小さいと共に１５ｋｇ／ｔｏｎより大きく、比較例８２〜８８では、攪拌量が６５ｋＪ／ｔｏｎより小さいと共に８５ｋＪ／ｔｏｎより大きい。
これら比較例５５〜８８では、前精錬処理にて耐火物の改質等を十分に行うことができなかったため、実施例と比べて、鋼材５ｔｏｎ当たりの断線回数が大幅に増加した。
In Comparative Examples 76 to 81, the slag basic unit is smaller than 5 kg / ton and larger than 15 kg / ton. In Comparative Examples 82 to 88, the stirring amount is smaller than 65 kJ / ton and larger than 85 kJ / ton.
In these comparative examples 55 to 88, since the refractory could not be sufficiently reformed by the pre-smelting treatment, the number of disconnections per 5 ton of steel material was significantly increased as compared with the examples.
比較例８９〜１２２は、本精錬処理における条件が本発明に規定した条件から外れたものである。比較例８９〜９１では[sol．Al]が２ppmよりも大きく、比較例９２〜９７ではスラグの塩基度が０．５より小さいと共に１．２より大きく、比較例９８〜１０３ではスラグのＡｌ２Ｏ３が５質量％より小さいと共に１５質量％より大きく、比較例１０４〜１０９ではスラグのＭｇＯが２質量％小さいと共に１５質量％より大きい。 In Comparative Examples 89 to 122, the conditions in the present refining treatment are out of the conditions defined in the present invention. In Comparative Examples 89 to 91, [sol. Al] is greater than 2 ppm, in Comparative Examples 92-97, the basicity of the slag is less than 0.5 and greater than 1.2, and in Comparative Examples 98-103, the slag Al 2 O 3 is less than 5% by mass. It is larger than 15% by mass, and in Comparative Examples 104 to 109, MgO of the slag is 2% by mass smaller and larger than 15% by mass.
また、比較例１１０〜１１５ではスラグ原単位が５ｋｇ／ｔｏｎより小さいと共に１５ｋｇ／ｔｏｎより大きく、比較例１１６〜１２２では、攪拌量が４０ｋＪ／ｔｏｎより小さいと共に６０ｋＪ／ｔｏｎより大きい。
これら比較例８９〜１２２では、本精錬処理にて耐火物の改質等を十分に行うことができなかったため、実施例と比べて、鋼材５ｔｏｎ当たりの断線回数が大幅に増加した。
In Comparative Examples 110 to 115, the slag basic unit is smaller than 5 kg / ton and larger than 15 kg / ton, and in Comparative Examples 116 to 122, the stirring amount is smaller than 40 kJ / ton and larger than 60 kJ / ton.
In these comparative examples 89 to 122, since the refractory could not be sufficiently reformed by this refining treatment, the number of disconnections per 5 ton of steel material was significantly increased as compared with the examples.
さらに、比較例１２３〜１３０では、本精錬処理を連続的に行ってソーワイヤ鋼を溶製した場合、２回目の本精錬処理の条件が１つでも本発明に規定する条件を満たさなければ、当該２回目の本精錬処理で溶製したソーワイヤ鋼でソーワイヤを製造したときに、鋼材５ｔｏｎ当たりの断線回数が大幅に増加した。
図６は、実施例及び比較例における断線回数をまとめたものである。
Furthermore, in Comparative Examples 123 to 130, when the present refining process is continuously performed and the saw wire steel is melted, even if one of the conditions of the second refining process does not satisfy the conditions defined in the present invention, When saw wire was manufactured with saw wire steel melted in the second main refining process, the number of disconnections per 5 ton of steel material increased significantly.
FIG. 6 summarizes the number of disconnections in the examples and comparative examples.
図６に示すように、粗骨材や微細骨材において、全材料に対する粗骨材の割合、粗骨材における１００μｍ以下の結晶径の割合、微細骨材における２０〜６０μｍの結晶径の割合、１０μｍ以下の結晶径の割合が本発明に規定した数値を満たす実施例では、断線回数を比較例に比べて非常に小さくすることができた。一方、全材料に対する粗骨材の割合、粗骨材における１００μｍ以下の結晶径の割合、微細骨材における２０〜６０μｍの結晶径の割合、１０μｍ以下の結晶径の割合のいずれか１つでも満たさない比較例は、実施例に比べて断線回数が非常に大きくなった。なお、前精錬処理における溶鋼の攪拌量と断線回数との関係をまとめると図７に示すようになり、本精錬処理における溶鋼の攪拌量と断線回数との関係をまとめると図８に示すようになる。 As shown in FIG. 6, in coarse aggregate and fine aggregate, the ratio of coarse aggregate to all materials, the ratio of crystal diameter of 100 μm or less in coarse aggregate, the ratio of crystal diameter of 20-60 μm in fine aggregate, In the example in which the ratio of the crystal diameter of 10 μm or less satisfies the numerical value defined in the present invention, the number of disconnections can be made much smaller than that in the comparative example. On the other hand, any one of the ratio of the coarse aggregate to the total material, the ratio of the crystal diameter of 100 μm or less in the coarse aggregate, the ratio of the crystal diameter of 20 to 60 μm in the fine aggregate, and the ratio of the crystal diameter of 10 μm or less is satisfied. In the comparative example that does not exist, the number of disconnections was much larger than that in the example. The relationship between the amount of stirring of molten steel and the number of disconnections in the pre-refining process is summarized as shown in FIG. 7, and the relationship between the amount of stirring of molten steel and the number of disconnections in the present refining process is summarized as shown in FIG. Become.
以上、本発明によれば、取鍋に施工する耐火物によるアルミナ介在物の抑制、本精錬処
理の前における耐火物の改質、本精錬処理における耐火物の改質及びアルミナ介在物の抑制とを行っていることから、断線回数の少ない高強度なソーワイヤを製造することができる。
なお、今回開示された実施形態において、明示的に開示されていない事項、例えば、運転条件や操業条件、各種パラメータ、構成物の寸法、重量、体積などは、当業者が通常実施する範囲を逸脱するものではなく、通常の当業者であれば、容易に想定することが可能な事項を採用している。
As described above, according to the present invention, the suppression of alumina inclusions by the refractory applied to the ladle, the modification of the refractory before the refining treatment, the modification of the refractory in the refining treatment, and the suppression of the alumina inclusion Therefore, it is possible to manufacture a high-strength saw wire with a small number of disconnections.
It should be noted that matters not explicitly disclosed in the embodiment disclosed this time, such as operating conditions and operating conditions, various parameters, dimensions, weights, volumes, and the like of a component, deviate from the range normally practiced by those skilled in the art. However, matters that can be easily assumed by those skilled in the art are employed.
１ 取鍋
２ 耐火物
２ａ 第１パーマ煉瓦
２ｂ 第２パーマ煉瓦
２ｃ キャスタブル
３ 鉄皮
４ 胴部
６ 底部（敷部）
８ 排出口
１０ 粗骨材
１１ 微細骨材
２０ 溶鋼
２１ 二次精錬設備
２２ 電極式加熱装置
２３ 底吹き用プラグ
DESCRIPTION OF SYMBOLS 1 Ladle 2 Refractory 2a 1st perm brick 2b 2nd perm brick 2c Castable 3 Iron skin 4 Trunk part 6 Bottom part (laying part)
8 Discharge port 10 Coarse aggregate 11 Fine aggregate 20 Molten steel 21 Secondary refining equipment 22 Electrode heating device 23 Bottom blowing plug
Claims (1)
前記精錬処理に使用する取鍋に施工する耐火物に関し、
当該耐火物の原料は、１ｍｍ以上のアルミナ粒子からなる粗骨材と、１ｍｍ未満のアルミナ粒子からなる微細骨材とを有しており、前記粗骨材に関し、その質量割合は、耐火物の原料の全量の４０％以上６０％以下とし、結晶径が１００μｍ以下である粗骨材の体積割合は粗骨材の全体積の３％以下とし、前記微細骨材に関し、結晶径が２０〜６０μｍである微細骨材の体積割合は微細骨材の全体積の５％以下とし、結晶径が１０μｍ以下である微細骨材の体積割合は微細骨材の全体積の４０％以上としており、
前記取鍋での精錬処理に関し、
ソーワイヤ用鋼を精錬する処理の１つ前に実施する精錬処理では、使用するスラグの組成を、Ｃ／Ｓ＝０．５〜１．２、Ａｌ２Ｏ３＝５〜１５質量％、ＭｇＯ＝２〜１５質量％とし、前記スラグの原単位を５〜１５ｋｇ／ｔｏｎとし、溶鋼の攪拌量を６５〜８５ｋＪ／ｔｏｎとすると共に、[sol．Al]を８ppm以下とし、
ソーワイヤ用鋼を精錬する処理では、使用するスラグの組成を、Ｃ／Ｓ＝０．５〜１．２、Ａｌ２Ｏ３＝５〜１５質量％、ＭｇＯ＝２〜１５質量％とし、前記スラグの原単位を５〜１５ｋｇ／ｔｏｎとし、溶鋼の攪拌量を４０〜６０ｋＪ／ｔｏｎとすると共に、[sol．Al]を２ppm以下としていることを特徴とするソーワイヤ用鋼の製造方法。 When manufacturing steel for saw wire by refining molten steel in a ladle,
Regarding the refractory to be constructed in the ladle used for the refining process,
The raw material of the refractory material has a coarse aggregate made of alumina particles of 1 mm or more and a fine aggregate made of alumina particles of less than 1 mm. The volume ratio of the coarse aggregate having a crystal diameter of 40% to 60% and a crystal diameter of 100 μm or less of the total amount of the raw material is 3% or less of the total volume of the coarse aggregate. The volume ratio of the fine aggregate is 5% or less of the total volume of the fine aggregate, and the volume ratio of the fine aggregate having a crystal diameter of 10 μm or less is 40% or more of the total volume of the fine aggregate,
Regarding refining treatment in the ladle,
In the refining process performed immediately before the process for refining saw wire steel, the composition of the slag used is C / S = 0.5 to 1.2, Al 2 O 3 = 5 to 15% by mass, MgO = 2-15 mass%, the basic unit of the slag is 5-15 kg / ton, the stirring amount of the molten steel is 65-85 kJ / ton, and [sol. Al] is 8 ppm or less,
In the processing for refining saw wire steel, the composition of slag used is C / S = 0.5 to 1.2, Al 2 O 3 = 5 to 15% by mass, MgO = 2 to 15% by mass, and the slag The basic unit is 5 to 15 kg / ton, the stirring amount of the molten steel is 40 to 60 kJ / ton, and [sol. A method for producing steel for saw wire, characterized in that Al] is 2 ppm or less.
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