JPS5856021B2 - High cleanliness steel and its manufacturing method - Google Patents
High cleanliness steel and its manufacturing methodInfo
- Publication number
- JPS5856021B2 JPS5856021B2 JP51152842A JP15284276A JPS5856021B2 JP S5856021 B2 JPS5856021 B2 JP S5856021B2 JP 51152842 A JP51152842 A JP 51152842A JP 15284276 A JP15284276 A JP 15284276A JP S5856021 B2 JPS5856021 B2 JP S5856021B2
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- steel
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- oxide
- inclusions
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Description
【発明の詳細な説明】
本発明は例えば線材に使用する炭素鋼で特に非金属介在
物が少なくかつ酸化物系非金属介在物の硬度が低い高清
浄度鋼とその製造法に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-cleanliness carbon steel used, for example, in wire rods, in which nonmetallic inclusions are particularly small and oxide nonmetallic inclusions have low hardness, and a method for producing the same.
従来より非金属介在物の鋼材に及ぼす影響については種
々論じられている。Various discussions have been made regarding the effects of nonmetallic inclusions on steel materials.
特にＡｌ２Ｏ３，ＳｉＯ２゜Ｃａｂ、ＴｉＯ２，ＭｇＯ
等の単体の酸化物系介在物は硬度も高く非粘性であり、
表面疵、ラミネーション、他流等の原因となる。Especially Al2O3, SiO2゜Cab, TiO2, MgO
Single oxide inclusions such as are highly hard and non-viscous;
This may cause surface flaws, lamination, other flow, etc.
また、冷間加工性、張出し成形性等を著しく悪化させる
。Moreover, cold workability, stretch formability, etc. are significantly deteriorated.
例えば線材においてはこれら単体の酸化物系介在物は、
伸線中の断線回数を多くシ、製品の捻回値や疲労等の機
械的性質を悪化させる。For example, in wire rods, these single oxide inclusions are
This increases the number of wire breaks during wire drawing, which worsens the mechanical properties such as twisting value and fatigue of the product.
このため、鋼板、鋼管、線材等鋼種のいかんにかかわら
ず、非金属介在物、特に酸化物系介在物の問題に悩まさ
れてきた。For this reason, regardless of the type of steel such as steel plates, steel pipes, and wire rods, the problem of nonmetallic inclusions, particularly oxide inclusions, has been a problem.
また、これまでに酸化物系非金属介在物を減少させるた
めに種々の方法、例えば真空脱ガス法、真空取鍋処理法
などが利用されているが、建設費、処理費用、処理時間
などの点で必ずしも満足のいくものではなかった。In addition, various methods have been used to reduce oxide-based nonmetallic inclusions, such as vacuum degassing and vacuum ladle treatment, but these methods are expensive due to construction costs, processing costs, processing time, etc. It was not always satisfactory in that respect.
それ故、安価にして容易に酸化物系非金属介在物を減少
させる手段の開発が望まれていた。Therefore, it has been desired to develop a means for easily reducing oxide-based nonmetallic inclusions at low cost.
本発明はこのような問題を解決することを目的として発
明したものである。The present invention was invented with the aim of solving such problems.
すなわち本発明は次の要旨を特徴とするものである。That is, the present invention is characterized by the following points.
（１） Ｃ二 ０．２４〜０．９５％ 、 Ｓ
ｉ ： ０．１２〜０．３５％ 。(1) C2 0.24-0.95%, S
i: 0.12-0.35%.
Ｍｎ 二〇、３０〜０．９０％、Ｐ：０．０４０％以下
。Mn 20, 30-0.90%, P: 0.040% or less.
Ｓ：０．０４０％以下、残部鉄からなる鋼において全酸
素量が５０ｐｐｍ以下、非粘性介在物インデックスが１
５以下で、かつ酸化物系非金属介在物の硬度ＭＩｙ（ｖ
が７００以下のロードナイト質複合介在物であることを
特徴とする高清浄度鋼。S: 0.040% or less, total oxygen content is 50 ppm or less in steel with balance iron, non-viscous inclusion index is 1
5 or less, and the hardness MIy (v
1. A high-cleanliness steel characterized by rhodonite composite inclusions having a particle diameter of 700 or less.
（２）Ｃ：０．２４〜０．９５％、Ｓｉ：０．１２〜０
．３５％。(2) C: 0.24-0.95%, Si: 0.12-0
．． 35%.
Ｍｎ ： ０．３ Ｃ）〜０．９０％、Ｐ：０．０４０
％以下。Mn: 0.3 C) ~ 0.90%, P: 0.040
%below.
Ｓ：０．０４０％以下、全酸素量が５０ｐｐｍ以下、非
粘性介在物インデックスが１５以下で、かつ酸化物系非
金属介在物の硬度ＭＨｖが７００以下のロードナイト質
複合介在物である高清浄度鋼の製造にあたり、アルゴン
を吹込む取鍋精錬法によりＣａＣ２など炭素を含みかつ
ＦｅＯ＜１％の還元性スラグにアルカリ金属の弗化物、
酸化物、アルカリ土類金属の弗化物の滓化促進化合物を
５〜３０％添加した低融点合成スラグを使用して溶鋼を
拡散脱酸し、更に調整脱酸剤としてＭｇ、Ｃａ等を適量
添加することを特徴とする高清浄度鋼の製造方法。S: High cleanliness which is a rhodonite composite inclusion of 0.040% or less, a total oxygen content of 50 ppm or less, a non-viscous inclusion index of 15 or less, and a hardness MHv of oxide-based nonmetallic inclusions of 700 or less. In manufacturing steel, a ladle refining method in which argon is injected is used to add alkali metal fluorides,
Molten steel is diffused and deoxidized using low melting point synthetic slag to which 5 to 30% of slag accelerating compounds of oxides and alkaline earth metal fluorides are added, and appropriate amounts of Mg, Ca, etc. are added as adjustment deoxidizers. A method for manufacturing high-cleanliness steel, characterized by:
これにより本発明は従来見られなかった軟質な酸化物系
非金属介在物を有し、且つ清浄度及び機械的諸性質が著
しく改善された高清浄鋼を可能とする。As a result, the present invention makes it possible to produce highly clean steel that has soft oxide-based nonmetallic inclusions that have not been seen before, and that has significantly improved cleanliness and mechanical properties.
また該清浄鋼は従来の製造法に比較して、簡単な設備、
安価な処理費用、短時間の処理によって得ることができ
、これら顕著な効果は従来の問題点を悉く解決し、本発
明の意図する所期の目的を達成する。In addition, compared to conventional manufacturing methods, the clean steel requires simple equipment and
It can be obtained with low processing cost and short processing time, and these remarkable effects solve all the conventional problems and achieve the intended purpose of the present invention.
以下本発明を線材（伸線材）を例として、更に詳細に説
明する。The present invention will be explained in more detail below using a wire rod (drawn wire rod) as an example.
伸線中に断線がおこることは製造工程を乱し、生産性を
著しく悪化させる。Wire breakage during wire drawing disrupts the manufacturing process and significantly reduces productivity.
またＡｌ２Ｏ３，ＳｉＯ２゜Ｃａｂ、ＴｉＯ２，ＭｇＯ
等の単体の酸化物系非金属介在物は硬度も硬く、その存
在は断線をひきおこす大きな原因であった。Also, Al2O3, SiO2°Cab, TiO2, MgO
Single oxide-based nonmetallic inclusions such as these are hard and their presence is a major cause of wire breakage.
伸線材の捻回値や疲労特性などの機械的性質も単体の酸
化物系非金属介在物によって著しく悪化することがわか
っている。It is known that the mechanical properties of drawn wire materials, such as torsion value and fatigue properties, are significantly deteriorated by single oxide-based nonmetallic inclusions.
それ故、単体の酸化物系非金属介在物の少ない高清浄度
鋼を得ることは線材の製造にたずされるもののひとしく
念願とするところであった。Therefore, it has been a common desire of those involved in the manufacture of wire rods to obtain highly clean steel with few single oxide-based nonmetallic inclusions.
通常、転炉、電気炉、平炉等で溶製された溶鋼は過剰な
酸素を含んでいるので、脱酸されるが、脱酸剤による強
制脱酸の場合には脱酸生成物の除去が大切である。Normally, molten steel made in a converter, electric furnace, open hearth, etc. contains excess oxygen and is deoxidized, but in the case of forced deoxidation using a deoxidizer, the deoxidation products cannot be removed. It's important.
高級炭素キルド鋼としマクロ組織を健全なものとし偏析
を低減するため、強力な脱酸剤（ＡＡ、Ｃａ、Ｍｇ、Ｔ
ｉ 、Ｚｒ等）が使用されるが、その元素単味の酸化物
が生成し、非粘性介在物となることが多い。In order to make high-grade carbon-killed steel with a healthy macrostructure and reduce segregation, strong deoxidizing agents (AA, Ca, Mg, T
i, Zr, etc.), but oxides of the elements alone are often produced, resulting in non-viscous inclusions.
本発明は上述の点に留意し、酸化物系非金属介在物に起
因する諸問題を一挙に解決したものである。The present invention takes the above-mentioned points into consideration and solves all the problems caused by oxide-based nonmetallic inclusions at once.
すなわち、本発明はＡｒを吹込む取鍋精錬法においてＣ
ａＣ２など炭素を含み、かつＦｅＯ＜１％の還元性スラ
グにアルカリ金属の弗化物、酸化物、アルカリ土類金属
の弗化物の１種もしくはそれ以上含む滓化促進化合物を
５〜３０％添加した低融点合成スラグを使用して溶鋼を
拡散脱酸し、更に調整脱酸剤としてＭｇ、Ｃａ等を適量
添加することによって得られ、Ｃ：０．２４〜０．９５
％。That is, the present invention provides C in a ladle refining method in which Ar is injected.
5 to 30% of a slag promoting compound containing one or more of alkali metal fluorides, oxides, and alkaline earth metal fluorides is added to reducing slag that contains carbon such as aC2 and has FeO<1%. Obtained by diffusion deoxidizing molten steel using low melting point synthetic slag, and further adding appropriate amounts of Mg, Ca, etc. as adjusting deoxidizers, C: 0.24-0.95
%.
Ｓ ｉ ： ０．１２〜０．３５％、 Ｍｎ ： ０．
３０〜０．９０％、Ｐ二０．０４０％以下、Ｓ：０．０
４０％以下、残り鉄および不可避不純物からなる鋼で全
酸素量が５０ｐｐｍ以下、非粘性介在物インデックスが
１５以下で、かつ酸化物系非金属介在物の硬度ＭＨｖが
７００以下のロードナイト質複合介在物であることを特
徴とする高清浄度鋼及びその製造法である。Si: 0.12-0.35%, Mn: 0.
30-0.90%, P2 0.040% or less, S: 0.0
Rhodonitic composite inclusions in which the total oxygen content is 50 ppm or less, the inviscid inclusion index is 15 or less, and the hardness MHv of the oxide nonmetallic inclusions is 700 or less in steel consisting of 40% or less, residual iron and inevitable impurities. The present invention provides a high-cleanliness steel and a method for producing the same.
まず、本発明において成分を規定した理由を述べる。First, the reason for defining the components in the present invention will be described.
前述のように線材は伸線して使用されるが断線などの伸
線性および製品の捻回値、疲労性などの機械的性質が特
に重要視されるのはキルド鋼の高炭素鋼である。As mentioned above, wire rods are used after being drawn, but high carbon steels such as killed steels are particularly important for wire drawability such as wire breakage and mechanical properties such as product torsion value and fatigue resistance.
現在高炭素鋼線材として広く用イられティるのは、Ｊ
ＩＳ Ｇ３５０２．Ｇ３５０６のピアノ線材、硬鋼線材
である。The currently widely used high carbon steel wire rod is J
IS G3502. G3506 piano wire and hard steel wire.
これらの規格はそれぞれ以下のとおりである。These standards are as follows.
上記ＪＩＳ範囲と製造の容易さ、実用面を考慮して本発
明では次のとおり成分範囲を規定した。In consideration of the above JIS range, ease of production, and practical aspects, the following component ranges were defined in the present invention.
（１）Ｃ：０．２４〜０．９５％
Ｃが低くなればなるほど溶鋼中のＣと０の平衡関係によ
り０量が増加してくる。(1) C: 0.24 to 0.95% As C becomes lower, the amount of zero increases due to the equilibrium relationship between carbon and zero in the molten steel.
脱酸によりこのＯを除去しキルド鋼とするわけである。This O is removed by deoxidation to produce killed steel.
溶鋼中のＯを低くシ、発生する酸化物系介在物を少なく
するためにＣの下限をＪＩＳ硬鋼線材の０．２４％とし
た。In order to keep the O content in the molten steel low and to reduce the amount of oxide inclusions generated, the lower limit of C was set to 0.24% of the JIS hard steel wire rod.
Ｃが０．８０％以上になると過共析鋼となり初析セメン
タイトが出現する。When the C content exceeds 0.80%, the steel becomes hypereutectoid and pro-eutectoid cementite appears.
Ｃが０．８０％以上より多くなればなるほど初析セメン
タイトが網目状となり、線材を脆化させ加工性が劣化す
る。As the C content increases beyond 0.80%, the pro-eutectoid cementite becomes network-like, embrittles the wire, and deteriorates workability.
それ故、Ｃの上限を現在実用に供されて問題のないＪＩ
Ｓピアノ線材の０．９５％とした。Therefore, we set the upper limit of C to JI, which is currently in practical use and has no problems.
It was set as 0.95% of S piano wire.
（２） Ｓｉ ： ０．１２〜０．３５％酸化物系非
金属介在物をロードナイト質複合介在物とするためには
Ｓｉは必須元素である。(2) Si: 0.12 to 0.35% Si is an essential element in order to convert oxide-based nonmetallic inclusions into rhodonite composite inclusions.
溶鋼中のＯを十分に低くするためには最低ＪＩＳピアノ
線材のＳｉ０．１２％は必要である。In order to sufficiently reduce the O content in molten steel, a minimum of 0.12% Si is required for JIS piano wire.
それ故Ｓｉの下限を０．１２％とした。Therefore, the lower limit of Si was set at 0.12%.
また溶鋼中のＯの低減効果の飽和、経済性、線材熱間圧
延の際のフェライト脱炭の問題よりＳｉの上限をＪＩＳ
硬鋼線材の０．３５％とした。In addition, due to the saturation of the O reduction effect in molten steel, economic efficiency, and the problem of ferrite decarburization during hot rolling of wire rods, the upper limit of Si has been set according to the JIS standard.
It was set as 0.35% of the hard steel wire rod.
（３） Ｍｎ ： ０．３０〜０．９０％酸化物系非
金属介在物をロードナイト質複合介在物とするためには
Ｍｎは必須元素である。(3) Mn: 0.30-0.90% Mn is an essential element in order to convert oxide-based nonmetallic inclusions into rhodonite composite inclusions.
熱間圧延時の割れ発生防止、線材の靭性確保には最低Ｊ
ＩＳ硬鋼線材の０．３０％は必要である。Minimum J to prevent cracking during hot rolling and ensure wire rod toughness
0.30% of IS hard steel wire is required.
それ故Ｍｎの下限を０．３０％とした。Therefore, the lower limit of Mn was set to 0.30%.
Ｍｎは焼入性をよくする元素である。Mn is an element that improves hardenability.
高Ｍｎ材は偏析部に局部的にミクロマルテンサイトなど
の異常組織が出現し断線、靭性低下の原因となる。In high-Mn materials, abnormal structures such as micromartensite appear locally in segregated areas, causing wire breakage and reduced toughness.
それ故、Ｍｎの上限を実用上このような問題のおきにく
いＪＩＳ硬鋼線材の０．９０％とした。Therefore, the upper limit of Mn was set at 0.90% for JIS hard steel wire rods, which are less prone to such problems in practice.
（４）Ｐ：０．０４０％以下
Ｐが多くなると線材に縞状組織と呼ばれる特有の組織が
出現し断線、靭性低下の原因となる。(4) P: 0.040% or less When the P content increases, a unique structure called a striped structure appears in the wire, causing wire breakage and a decrease in toughness.
それ故、Ｐは実用上このような問題がおこらないＪＩＳ
硬鋼線材の０．０４０％以下とした。Therefore, P is a JIS standard that does not have this problem in practice.
It was set to 0.040% or less of the hard steel wire rod.
（５）Ｓ二０．０４０％以下
Ｓはできるだけ低い方が好ましいが、０．０４０％以下
であれば硫化物は伸延していくので靭性劣化の影響が少
なく問題ない。(5) S2: 0.040% or less It is preferable that S be as low as possible, but if it is 0.040% or less, the sulfide will be elongated, so there will be little effect on toughness deterioration and there will be no problem.
それ故、上記の範囲を包括して Ｃ：０．２４〜０．９５％ Ｓｉ 二 ０．１２〜０．３５％ Ｍｎ ： ０．３０＝０．９０％ Ｐ ：０．０４０％以下 Ｓ 二０．０４０％以下とした。Therefore, encompassing the above range C: 0.24-0.95% Si2 0.12-0.35% Mn: 0.30=0.90% P: 0.040% or less S2: 0.040% or less.
鋼中の全酸素量が多くなればなるほど鋼中の酸化物系非
金属介在物は増加する。As the total amount of oxygen in the steel increases, the number of oxide-based nonmetallic inclusions in the steel increases.
また、全酸素量が多くなると、脱酸度が弱くなり、鋼塊
のマクロ組織が不健全なものとなり、ブローホール、ピ
ンホール等が出現し好ましくない。Furthermore, if the total amount of oxygen increases, the degree of deoxidation will become weaker, the macrostructure of the steel ingot will become unhealthy, and blowholes, pinholes, etc. will appear, which is undesirable.
酸化物系非金属介在物量も少なく高清浄でかつ鋼塊性状
を健全なものとするためには、全酸素量を５０ｐｐｍ以
下におさえる必要がある。In order to achieve high purity with a small amount of oxide-based nonmetallic inclusions and healthy steel ingot properties, it is necessary to suppress the total oxygen content to 50 ppm or less.
更に酸化物系非金属介在物を延伸性のある軟質なものと
するためには、硬度■ｈが７００以下のロードナイト質
複合介在物にする必要がある。Furthermore, in order to make the oxide-based nonmetallic inclusion soft and extensible, it is necessary to make it a rhodonite composite inclusion with a hardness of 700 or less.
（硬度Ｍｌｉ（ｖはマイクロビッカース硬度を意味する
。(Hardness Mli (v means micro Vickers hardness.
）硬度が７００以上になるとＳ １０２ Ａ１２０３
、” ”０ 。) When the hardness is 700 or more, S 102 A1203
,” ”0.
Ｔ Ａ０２２Ｍｇ０等の単体の酸化物系非金属介在物が
出現しはじめ、非粘性介在物インデックスも急に増大す
る傾向がみられる。Single oxide nonmetallic inclusions such as T A022Mg0 begin to appear, and the inviscid inclusion index also tends to increase rapidly.
非粘性介在物インデックスとは５．５ｍｍφ線材におい
て中心線を通る縦断面にて６０．５ ｍｍ’Ｏｙ＠域を
２００倍の顕微鏡を用いて全面観察し、ＪＩＳ ＧＯ５
５５に規定されたＢあるいはＣ系介在物のうち５μ以上
のものを数える。What is the non-viscous inclusion index? A 60.5 mm'Oy @ area is observed in a longitudinal section passing through the center line of a 5.5 mm diameter wire using a microscope with a magnification of 200 times, and is determined by JIS GO5.
Among the B or C-based inclusions specified in 55, those with a size of 5μ or more are counted.
そして５〜１０μの介在物個数には×１゜１０〜２０μ
にはＸ５，２０μ〜には×２０倍してその数を合計した
ものである。And for the number of inclusions of 5 to 10μ, ×1゜10 to 20μ
is multiplied by x5, and from 20μ is multiplied by x20 and the numbers are summed.
長年にわたる研究の結果、この非粘性介在物インデック
スが１５以上となると伸線中の断線回数が増大し、伸線
材の機械的性質も劣化することがわかった。As a result of many years of research, it has been found that when the inviscid inclusion index is 15 or more, the number of wire breaks during wire drawing increases and the mechanical properties of the wire drawn material also deteriorate.
また清浄度も悪化し好ましくない。本発明は以上述べた
ように全酸素を５０ｐｐｍ以下とし、組織を健全なもの
とし更に酸化物系非金属介在物の発生量を少なくする。Moreover, the cleanliness deteriorates, which is not preferable. As described above, the present invention reduces the total oxygen content to 50 ppm or less, makes the structure healthy, and further reduces the amount of oxide-based nonmetallic inclusions.
また、酸化物系非金属介在物の硬度をＭＨｖ ７００以
下のロードナイト質複合介在物とし軟質なものとする。Further, the hardness of the oxide-based non-metallic inclusions is made into a soft rhodonitic composite inclusion with a hardness of MHv 700 or less.
軟質な酸化物系非金属介在物とすることにより、非粘性
介在物インデックスは１５以下というゆるい制約でも従
来の線材にはみられないような伸線性が良好で、かつ伸
線材の機械的性質のすぐれた高清浄度鋼が得られた。By using soft oxide-based non-metallic inclusions, even with the loose restriction that the non-viscous inclusion index is 15 or less, it has good wire drawability that is not seen in conventional wire rods, and improves the mechanical properties of the wire drawing material. Excellent high-cleanliness steel was obtained.
酸化物系非金属介在物の硬度ＭＨｖが７００以下のロー
ドナイト質複合介在物に抑えることが重要なのである。It is important to suppress the hardness MHv of the oxide-based nonmetallic inclusions to rhodonite composite inclusions of 700 or less.
本発明は上述のように全酸素量、非粘性介在物インデッ
クス、酸化物系非金属介在物の硬度と形態を規定した点
と以下に述べる還元性スラグを用いた取鍋精錬による拡
散脱酸とＭｇ、Ｃａ等による調整脱酸を用いて製造する
ことが重要なのである。The present invention is characterized by the fact that the total oxygen content, inviscid inclusion index, hardness and form of oxide-based nonmetallic inclusions are defined as described above, and the diffusion deoxidation by ladle refining using reducing slag described below. It is important to manufacture using controlled deoxidation using Mg, Ca, etc.
この調整脱酸には純金属または合金系の調整脱酸剤を適
宜選択使用する。For this controlled deoxidation, a pure metal or alloy-based controlled deoxidizing agent is appropriately selected and used.
すなわち、本発明では鋼の製造における溶製工程ではよ
く知られた転炉、電気炉、平炉等で行えばよい。That is, in the present invention, the melting process in the manufacture of steel may be carried out using well-known converter furnaces, electric furnaces, open hearth furnaces, etc.
この点については特に問題はない。前記炉で溶製された
溶鋼を取鍋に受鋼する際、成分調整のためにＦ ｅ−Ｍ
ｎ 、 Ｆ ｅ −８ｉ 、 Ｓ ｉ−Ｍｎ等を添加す
る。There are no particular problems in this regard. When receiving the molten steel produced in the furnace into a ladle, F e-M is used to adjust the composition.
n, Fe-8i, Si-Mn, etc. are added.
受鋼抜取鍋底よりＡｒガスを吹込む。モして取鍋にＣａ
Ｃ２など炭素を含み、かつＦｅＯ〈１％の還元性スラグ
にアルカリ金属の弗化物、酸化物、アルカリ土類金属の
弗化物の滓化促進化合物を添加した低融点合成スラグを
添加する。Blow Ar gas from the bottom of the receiving steel ladle. Ca in the ladle
A low melting point synthetic slag is added to a reducing slag containing carbon such as C2 and 1% FeO and a slag promoting compound of an alkali metal fluoride, oxide, or alkaline earth metal fluoride.
受鋼時に不可避的に溶製工程での酸化性スラグが混入す
るので、取鍋中で拡散脱酸を有効に進行させるためにＦ
ｅｄ＜ １％の還元性スラグはＣａＣ２など炭素を含む
還元成分が必要である。When receiving steel, oxidizing slag from the melting process inevitably gets mixed in, so F is used to effectively promote diffusion deoxidation in the ladle.
Reducing slag with ed<1% requires a reducing component containing carbon such as CaC2.
ＣａＣ２など炭素を含む還元成分の融点は非常に高い。The melting point of a reducing component containing carbon such as CaC2 is very high.
例えばＣａＣ２単味の融点は２３００℃である。For example, the melting point of CaC2 alone is 2300°C.
それ故滓化促進化合物を含まない還元性スラグは、１６
００℃以下では十分滓化しない。Therefore, a reducing slag containing no slagging-promoting compounds is 16
It does not become a slag sufficiently at temperatures below 00°C.
また塊状になりやすく取鍋中では拡散脱酸が進行しない
。In addition, it tends to form lumps and diffusion deoxidation does not proceed in the ladle.
長年にわたる研究の結果、ＮａＦ 、ＫＦ 、Ｎａ２Ｏ
。ＣａＦ２などのアルカリ金属の弗化物、酸化物、アル
−Ｊｙ ＩＪ土類金属の弗化物の滓化促進化合物を５〜
３０％添加することにより取鍋中でも十分滓化し拡散脱
酸が進行することがわかった。As a result of many years of research, NaF, KF, Na2O
. Alkali metal fluorides such as CaF2, oxides, Al-Jy IJ earth metal fluoride slag promoting compounds are added to
It was found that by adding 30%, the slag was sufficiently formed even in the ladle, and diffusion deoxidation proceeded.
滓化促進化合物を５％以上添加しないと還元性スラグの
融点を１５００℃以下に下げ滓化速度をはやくすること
ができない。Unless 5% or more of the slag promoting compound is added, the melting point of the reducing slag cannot be lowered to 1500° C. or lower and the slag formation rate cannot be increased.
しかし、滓化促進化合物が３０％以上となると還元性ス
ラグと取鍋レンガとの反応が激しくなり好ましくない。However, if the slag-promoting compound exceeds 30%, the reaction between the reducing slag and the ladle bricks becomes intense, which is not preferable.
このように本発明の合成スラグは滓化促進化合物の添加
とＡｒガスの攪拌効果により短時間ですみやかに滓化し
取鍋中で十分に拡散現数が進行する。As described above, the synthetic slag of the present invention is rapidly turned into slag in a short period of time due to the addition of the slag-promoting compound and the stirring effect of Ar gas, and the diffusion rate progresses sufficiently in the ladle.
Ａｒガス吹込みにより溶鋼が十分攪拌され、成分、温度
が均一となり、拡散脱酸により溶鋼中の酸素が低下した
状態で、Ａｒガス吹込みにより溶鋼が露出している部分
に、Ｍｇ、Ｃａ等の脱酸剤を適量添加し調整脱酸を行う
。The molten steel is sufficiently stirred by the Ar gas injection, the composition and temperature are uniform, and the oxygen in the molten steel is reduced by diffusion deoxidation.The Ar gas injection adds Mg, Ca, etc. Add an appropriate amount of deoxidizer to perform adjusted deoxidation.
拡散脱酸により溶鋼中の酸素が低下し、更にＡｒ吹込み
により溶鋼の温度が均一となり、取鍋上の雰囲気も非酸
化性となった状態で、Ｍｇ、Ｃａ等の脱酸剤を添加する
ので、脱酸剤を有効に働かせることができ、また発生す
る酸化物系非金属介在物の数も少なく歩留も向上する。Oxygen in the molten steel is reduced by diffusion deoxidation, the temperature of the molten steel is made uniform by Ar injection, and the atmosphere above the ladle is non-oxidizing, then a deoxidizing agent such as Mg or Ca is added. Therefore, the deoxidizing agent can be used effectively, and the number of oxide-based nonmetallic inclusions generated is small, resulting in an improved yield.
拡散脱酸により溶鋼中の酸素が低下しているので従来よ
りＭｇ、Ｃａ等の脱酸剤の使用量が少なくてすむ。Since oxygen in the molten steel is reduced by diffusion deoxidation, the amount of deoxidizing agents such as Mg and Ca can be reduced compared to conventional methods.
それ故、溶鋼中にけんだくしている脱酸生成物量が少な
くなり、浮上性もよくなり、合成スラグに捕捉されやす
くなる。Therefore, the amount of deoxidation products suspended in the molten steel is reduced, the floatability is improved, and the products are easily captured by the synthetic slag.
調整脱酸を行うのは酸化物系非金属介在物の形態を軟質
なものとするためと、浮上性をよくするためである。The purpose of performing controlled deoxidation is to make the oxide-based nonmetallic inclusions soft and to improve their floating properties.
拡散脱酸のみではＳｉＯ２単体の介在物が出現し、酸化
物系非金属介在物は軟質なものとならず、清浄度も悪く
高清浄度鋼は製造できない。In the case of diffusion deoxidation alone, inclusions of simple SiO2 appear, oxide-based nonmetallic inclusions do not become soft, and the cleanliness is poor, making it impossible to produce high-cleanliness steel.
調整脱酸を行うことが重要なのである。このような本発
明によりＭｇ、Ｃａ等の強力な脱酸剤を添加しても５ｉ
ｎ２．ＣａＯ，ＭｇＯ等の非常に硬い単体の酸化物は生
成されず、ＳｉＯ２ＭｎＱを主体としたロードナイト質
けい酸塩が生成し酸化物系非金属介在物の硬度は非常に
低くなり、伸延性に富んだものとなる。It is important to perform controlled deoxidation. According to the present invention, even if strong deoxidizers such as Mg and Ca are added, 5i
n2. Very hard single oxides such as CaO and MgO are not generated, but rhodonite silicate mainly composed of SiO2MnQ is generated, and the hardness of oxide-based nonmetallic inclusions is extremely low, making it highly extensible. Become something.
全酸素量も十分低下し、５０ｐｐｍ以下となる。The total oxygen amount is also sufficiently reduced to 50 ppm or less.
従って本発明により容易に高清浄度鋼が製造できること
になる。Therefore, high cleanliness steel can be easily manufactured according to the present invention.
以下に本発明を実施例に基づき更に詳細に説明する。The present invention will be explained in more detail below based on examples.
第１表に実施例を示す。Examples are shown in Table 1.
実施例はすべて９０を転炉、９０を取鍋を用いて行った
試験である。All of the Examples were tests conducted using a 90° converter and a 90° ladle.
転炉より出鋼する際、Ｃ，Ｓｉ、Ｍｎの成分調整を行い
、第１表に示す溶鋼組成とした。When the steel was tapped from the converter, the components of C, Si, and Mn were adjusted to give the molten steel composition shown in Table 1.
受鋼後、取鍋底より吹込んだＡｒは流量１５０〜２５０
Ａ／ｍｉｎ 。After receiving the steel, the flow rate of Ar blown from the bottom of the ladle was 150 to 250.
A/min.
吹込時間は１５〜２０ｍ１ｎであった。The blowing time was 15-20 m1n.
調整脱酸剤はＡｒ吹込み５分後に添加した。The adjusted deoxidizer was added 5 minutes after Ar blowing.
Ａ−Ｇが本発明であり、Ｈ−Ｋが従来法である。A-G is the method of the present invention, and H-K is the conventional method.
本発明では全酸素が３０〜４５ｐｐｍと非常に低くなっ
ている。In the present invention, the total oxygen content is extremely low at 30 to 45 ppm.
溶鋼組成が類似しているものを比較すると明らかに本発
明の全酸素が低くなっている。When comparing molten steels with similar compositions, it is clear that the total oxygen content of the present invention is lower.
非粘性介在物インデックスも本発明では１５以下であり
、従来法の２１〜３５に比し著しく低くなっている。The non-viscous inclusion index is also 15 or less in the present invention, which is significantly lower than 21 to 35 in the conventional method.
本発明による線材では、５．５ｍｍφ段階になると酸化
物系非金属介在物は延伸され幅が１μ以下のものが大多
数となり、また数も少ないので硬度測定が困難である。In the wire rod according to the present invention, at the stage of 5.5 mm diameter, the oxide nonmetallic inclusions are stretched and the majority have a width of 1 μm or less, and since the number is small, it is difficult to measure the hardness.
それ故、第１表に示すものを、１２０Ｊ２ｒビレット段
階において、介在物の硬度を測定した。Therefore, the hardness of inclusions in the samples shown in Table 1 was measured at the 120J2r billet stage.
硬度を測定する際、荷重は２〜１０ｇとした。When measuring hardness, the load was 2 to 10 g.
第１表より本発明の酸化物系非金属介在物の硬度はいず
れも７００以下のロードナイト質複合介在物となり、非
常に軟質なものとなっていることがわかる。From Table 1, it can be seen that the hardness of the oxide-based nonmetallic inclusions of the present invention is all rhodonite composite inclusions of 700 or less, making them very soft.
比較材では１０００以上となり硬いことがわかる。It can be seen that the comparison material has a hardness of 1000 or more.
以上の第１表より還元性スラグと調整脱酸剤により高清
浄度鋼が製造可能なことがわかる。From Table 1 above, it can be seen that high cleanliness steel can be manufactured using reducing slag and adjusted deoxidizing agent.
次に前記１２０ｙビレツトを線材に圧延し、それを伸線
した際に得られた伸線材の特性値について述べる。Next, the characteristic values of the drawn wire obtained by rolling the 120y billet into a wire and drawing the same will be described.
線材はその炭素量によって種々の用途に用いられ、また
仕上りの線径も違うので、個々の場合に分割して本発明
の優位性を述べる。Wire rods are used for various purposes depending on their carbon content, and the finished wire diameters also differ, so the advantages of the present invention will be explained by dividing the wire rods into individual cases.
第２表には断線率インデックス、捻回値を示す。Table 2 shows the wire breakage rate index and twist value.
断線率インデックスとは伸線中の断線の程度を示すパラ
メーターであり、インデックスが低いほど断線回数が少
なくなり伸線性がよいことになる。The wire breakage rate index is a parameter indicating the degree of wire breakage during wire drawing, and the lower the index, the fewer the number of wire breakages and the better the wire drawability.
また捻回値は線径が２關φのものである。The twist value is based on a wire diameter of 2 mm.
第３表にはダイス摩耗インデックス、第１図には疲労特
性を示す。Table 3 shows the die wear index, and Figure 1 shows the fatigue properties.
炭素量が０．７０％前後のものはスチールコード用線材
として汎用されている。Those with a carbon content of around 0.70% are commonly used as wire rods for steel cords.
これは極細まで伸線されるのと、タイヤなどの振動を受
ける場所に使われるので特に品質特性に対する要求がき
びしいものである。This wire is drawn to an extremely fine wire and is used in areas subject to vibrations such as tires, so it has particularly strict requirements for quality characteristics.
それ故、炭素量が０．７０％前後のものについてはダイ
ス摩耗インデックスと疲労特性も調査した。Therefore, the die wear index and fatigue properties were also investigated for those with a carbon content of around 0.70%.
極細線の場合には伸線時のダイスの摩耗がはげしいと仕
上り線径が次第に増大し規格はずれとなる。In the case of ultra-fine wire, if the die is severely worn during wire drawing, the finished wire diameter will gradually increase and become out of specification.
それ故最終ダイスの摩耗のはげしさを示すダイス摩耗イ
ンデックスをも調査した。Therefore, the die wear index, which indicates the degree of wear of the final die, was also investigated.
これは０．１８ｍｒｎφ径の超硬ダイスでどれだけの伸
線が可能であるかを示すパラメーターである。This is a parameter indicating how much wire can be drawn with a carbide die having a diameter of 0.18 mrnφ.
ダイス摩耗インデックスが大きいほど伸線量が多くなり
、ダイス摩耗量が少ないことになる。The larger the die wear index, the greater the wire drawing amount, and the smaller the die wear amount.
これらの伸線材の特性値を示す第２゜３表、第１図より
次のことがいえる。The following can be said from Table 2.3 and FIG. 1 showing the characteristic values of these drawn wire materials.
炭素量が０．２５％クラスのものは、ＡとＨに示される
ように、本発明のＡでは断線率も小さく、かつ捻回値が
大きくなることがわかる。As shown in A and H, in the case of carbon content of 0.25% class, it can be seen that A of the present invention has a small disconnection rate and a large twist value.
炭素量が０．６０％クラスのものはＢとＣと■に示され
る。Those with a carbon content of 0.60% class are shown in B, C, and ■.
この場合も０．２５％クラスのものと同様に本発明のＢ
、Ｃの優位性が歴然としている。In this case as well, B of the present invention is similar to the 0.25% class.
, the superiority of C is clear.
炭素量０．７０％クラスのものはＤとＥとＪに示される
。Those with a carbon content of 0.70% class are shown in D, E, and J.
本発明のり、Ｅでは断線率インデックスが小さく、かつ
捻回値が大きい。The adhesive E of the present invention has a small wire breakage index and a large twist value.
またダイス摩耗インデックスも大きく、伸線時のダイス
摩耗量が少ないことがわかる。The die wear index is also large, indicating that the amount of die wear during wire drawing is small.
疲労特性であるが第１図に示すように本発明の優位性が
歴然としている。As for fatigue properties, the superiority of the present invention is clear as shown in FIG.
最後に炭素量が０．９５％クラスのものがＦとＧとＫに
示される。Finally, those with a carbon content of 0.95% class are shown in F, G, and K.
この場合も本発明が断線率インデックス、捻回値におい
てまさっていることがわかる。It can be seen that in this case as well, the present invention is superior in terms of wire breakage rate index and twist value.
以上の実施例よりわかるように本発明の高清浄度鋼の伸
線性、機械的性質が格段にすぐれていることがわかる。As can be seen from the above examples, it can be seen that the high cleanliness steel of the present invention has extremely excellent wire drawability and mechanical properties.
伸線性が著しく向上したのは酸化物系非金属介在物を軟
質なものとし、非粘性介在物インデックスを小さくした
ことにより、伸線の際ダイスにかかる抵抗を極力おさえ
、かつ線の有効断面積の減少をおさえたことによるもの
と思われる。The reason for the remarkable improvement in wire drawability is that the oxide-based nonmetallic inclusions are made soft and the non-viscous inclusion index is reduced, which minimizes the resistance applied to the die during wire drawing and increases the effective cross-sectional area of the wire. This seems to be due to the suppression of the decrease in
仕上り線の機械的性質が向上したのは、酸化物系非金属
介在物を軟質なものとしたために線の靭性が増したもの
と思われる。The improved mechanical properties of the finished wire are thought to be due to the softness of the oxide-based nonmetallic inclusions, which increased the toughness of the wire.
以上の実施例かられかるように本発明により伸線性、機
械的性質の著しく改善された全酸素量５０ｐｐｍ以下、
非粘性介在物インデックスが１５以下で、かつ酸化物系
非金属介在物の硬度ＭＨｖが７００以下のロードナイト
質複合介在物である高清浄度鋼が容易に製造できること
になる。As can be seen from the above examples, the present invention has significantly improved wire drawability and mechanical properties, with a total oxygen content of 50 ppm or less,
It is possible to easily produce high-cleanliness steel containing rhodonite composite inclusions in which the inviscid inclusion index is 15 or less and the hardness MHv of the oxide-based nonmetallic inclusions is 700 or less.
このような顕著な機械的性質を有する本発明の高清浄鋼
は、前述の如く、Ａｒを吹込む取鍋精錬法によって製造
されるものであるから、従来の真空脱ガス法、真空取鍋
処理法などに比較して簡単な設備、安価な処理費用、短
時間の処理等で得ることができ、高清浄鋼の効果ととも
に産業上の意義が犬なるものである。The high-clean steel of the present invention having such remarkable mechanical properties is produced by the ladle refining method in which Ar is injected, as described above, and therefore, it is not necessary to use the conventional vacuum degassing method or vacuum ladle treatment. It can be obtained with simple equipment, low processing costs, and short processing time compared to other methods, and has great industrial significance along with the effects of high-purity steel.
第１図は本発明と従来法 疲労特性を示したも である。 Ｅは本発明、 Ｊは従来法によるも である。 Figure 1 shows the present invention and conventional method Although it showed fatigue properties It is. E is the present invention, J is based on the conventional method It is.
Claims (1)
．３５％。 Ｍｎ ： ０．３０−０．９０％、Ｐ二Ｏ，０４０％以
下。 Ｓ：０．０４０％以下、残部鉄からなる鋼において全酸
素量が５０ ｐｐｍ以下、非粘性介在物インデックスが
１５以下で、かつ酸化物系非金属介在物の硬度ＭＨｖが
７００以下のロードナイト質複合介在物であることを特
徴とする高清浄度鋼。 ２ Ｃ：０．２４〜０．９５％、Ｓｉ：０．１２〜０
．３５％。 Ｍｎ ： ０．３０−０．９０％、Ｐ：０．０４０％以
下。 Ｓ：０．０４０％以下、全酸素量が５０ｐｐｍ以下、非
粘性介在物インデックスが１５以下で、かつ酸化物系非
金属介在物の硬度ＭＨｖが７００以下のロードナイト質
複合介在物である高清浄度鋼を製造するにあたり、アル
ゴンを吹込む取鍋精錬法によりＣａＣ２など炭素を含み
、かつＦｅＯ＜１％の還元性スラグにアルカリ金属の弗
化物、酸化物、アルカリ土類金属の弗化物の滓化促進化
合物を５〜３０％添加した低融点合成スラグを使用して
溶鋼を拡散脱酸し、更に調整脱酸剤としてＭｇ、Ｃａ等
を適量添加することを特徴とする高清浄度鋼の製造方法
。[Claims] l C: 0.24-0.95%, Si: 0.12-0
．． 35%. Mn: 0.30-0.90%, P2O, 040% or less. S: 0.040% or less, the total oxygen content is 50 ppm or less in steel with the balance being iron, the inviscid inclusion index is 15 or less, and the hardness of oxide nonmetallic inclusions is 700 or less. High cleanliness steel characterized by inclusions. 2C: 0.24-0.95%, Si: 0.12-0
．． 35%. Mn: 0.30-0.90%, P: 0.040% or less. S: High cleanliness, which is a rhodonite composite inclusion with a total oxygen content of 0.040% or less, a total oxygen content of 50 ppm or less, a non-viscous inclusion index of 15 or less, and a hardness MHv of oxide-based nonmetallic inclusions of 700 or less. In manufacturing steel, slag of alkali metal fluorides, oxides, and alkaline earth metal fluorides is converted into reducing slag containing carbon such as CaC2 and FeO<1% using a ladle refining method that blows argon. A method for producing high-cleanliness steel, which comprises diffusing and deoxidizing molten steel using low melting point synthetic slag to which 5 to 30% of accelerator compounds have been added, and further adding appropriate amounts of Mg, Ca, etc. as adjusting deoxidizers. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP51152842A JPS5856021B2 (en) | 1976-12-21 | 1976-12-21 | High cleanliness steel and its manufacturing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP51152842A JPS5856021B2 (en) | 1976-12-21 | 1976-12-21 | High cleanliness steel and its manufacturing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5376916A JPS5376916A (en) | 1978-07-07 |
| JPS5856021B2 true JPS5856021B2 (en) | 1983-12-13 |
Family
ID=15549313
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP51152842A Expired JPS5856021B2 (en) | 1976-12-21 | 1976-12-21 | High cleanliness steel and its manufacturing method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5856021B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB8332395D0 (en) * | 1983-12-05 | 1984-01-11 | Bekaert Sa Nv | Steel wires |
| US5298323A (en) * | 1989-10-11 | 1994-03-29 | Nippon Seiko Kabushiki Kaisha | Bearing steel and rolling bearing made thereof |
| JP2978038B2 (en) * | 1993-08-16 | 1999-11-15 | 新日本製鐵株式会社 | Oxide inclusion ultrafine dispersion steel |
| JP4718359B2 (en) | 2005-09-05 | 2011-07-06 | 株式会社神戸製鋼所 | Steel wire rod excellent in drawability and fatigue characteristics and manufacturing method thereof |
| CN104789739B (en) * | 2015-03-31 | 2016-08-31 | 青岛钢铁控股集团有限责任公司 | A kind of refining process molten steel uses the smelting process of carbide deoxidation |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5071507A (en) * | 1973-10-29 | 1975-06-13 |
-
1976
- 1976-12-21 JP JP51152842A patent/JPS5856021B2/en not_active Expired
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5071507A (en) * | 1973-10-29 | 1975-06-13 |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5376916A (en) | 1978-07-07 |
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