JPH0959744A - High carbon steel wire rod excellent in wire drawability and aging resistance and its production - Google Patents
High carbon steel wire rod excellent in wire drawability and aging resistance and its productionInfo
- Publication number
- JPH0959744A JPH0959744A JP7216203A JP21620395A JPH0959744A JP H0959744 A JPH0959744 A JP H0959744A JP 7216203 A JP7216203 A JP 7216203A JP 21620395 A JP21620395 A JP 21620395A JP H0959744 A JPH0959744 A JP H0959744A
- Authority
- JP
- Japan
- Prior art keywords
- wire rod
- less
- wire
- carbon steel
- ppm
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- 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)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、高炭素鋼線材及びその
製造方法に関し、特に、熱延後、線材中に1μm以上の
介在物量が少なく、冷間引抜加工性(伸線加工)及び耐
時効性に優れた高炭素鋼線材とその製造技術に係わる。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high carbon steel wire rod and a method for producing the same, and in particular, after hot rolling, the wire rod has a small amount of inclusions of 1 μm or more, and has cold drawability (wire drawing) and It is concerned with high carbon steel wire rods with excellent aging properties and their manufacturing technology.
【0002】[0002]
【従来の技術】自動車用のタイヤコード等に使用されて
いる高炭素鋼線材は、約5.5mmφまで熱間圧延し、
その後、パテンティング(焼入れの一種)を施しながら
数回の冷間引抜加工(伸線加工)を行い、最終的に0.
15mmφの極細線まで伸線される。2. Description of the Related Art High carbon steel wire rods used for automobile tire cords and the like are hot-rolled to about 5.5 mmφ,
After that, cold drawing (drawing) is performed several times while applying patenting (a type of quenching), and finally 0.
The wire is drawn up to an extra fine wire of 15 mmφ.
【0003】この伸線加工時に、鋼中に硬質な粒状の非
金属介在物(以下、介在物という)が存在していると、
マトリックスが伸延されても介在物が伸延せず、そのま
まの形状で存在すると、介在物の周辺にミクロボイドが
形成され、線材の延性が低下し断線の原因となる。そこ
で、断線の原因とならないよう鋼中介在物を微細化する
ため、製鋼工程では、脱酸生成物の組成を熱間圧延時に
延性の良好なAl2 O 3 −SiO2 −MnO3元系状態
図のスペサータイト領域に調整する必要があった。During this wire drawing process, hard granular non-
If metal inclusions (hereinafter referred to as inclusions) are present,
Even if the matrix is stretched, inclusions do not stretch, and
If it exists in the normal shape, micro voids will appear around the inclusions.
When formed, the ductility of the wire is reduced, which causes disconnection. There
To refine inclusions in steel so as not to cause wire breakage
Therefore, in the steelmaking process, the composition of the deoxidized product during hot rolling
Al with good ductility2 O Three -SiO2 -MnO ternary system state
It was necessary to adjust to the spessartite region in the figure.
【0004】このスペーサタイト領域に調整する方法と
しては、溶鋼中に添加する合金鉄中のAl量を溶鋼1t
on当たり10〜50g程度に規制する方法(特公昭5
2−17490号公報)、及び、それに加えて、Mn/
Siを1.7以上に規制する方法(特公昭57−229
69号公報)が提案されている。しかしながら、上記方
法では、Al量が規制され且つ溶鋼の脱酸がMn、Si
で行われるため、脱酸力が弱く、脱酸後、溶鋼中の残存
酸素量は高く、鋳片の清浄性が悪いという問題がある。
近年、タイヤコードの極細線化と高強度化の一層の進行
により、介在物微細化要求も一段と強くなり、熱延後の
線材で1μm以上の介在物量、酸素量の低減が必要で、
上記した介在物組成調整のみでは不十分となっている。
また、スペーサタイト領域の介在物になるようAl量を
規制し組成調整はしているが、溶鋼中の残存酸素量が高
いので該残存酸素がばらつき、生成介在物中のAl2 O
3 濃度が変化して介在物形態がばらつき、熱延時に該介
在物の微細化が難しいという問題もあった。As a method for adjusting the spacer tight region, the amount of Al in the ferroalloy added to the molten steel is adjusted to 1 t of molten steel.
How to control to about 10-50g per on
2-17490 gazette) and, in addition thereto, Mn /
A method of controlling Si to 1.7 or more (Japanese Patent Publication No. 57-229).
No. 69) has been proposed. However, in the above method, the amount of Al is regulated and deoxidation of molten steel is caused by Mn and Si.
Therefore, there is a problem that the deoxidizing power is weak, the residual oxygen amount in the molten steel after deoxidizing is high, and the cleanliness of the slab is poor.
In recent years, due to the further progress of ultra-thin tire cords and higher strength, the demand for finer inclusions has become even stronger, and it is necessary to reduce the inclusion amount of 1 μm or more and the oxygen amount in the wire rod after hot rolling.
It is not sufficient to adjust the composition of the inclusions alone.
Further, although the amount of Al is regulated and the composition is adjusted so as to become inclusions in the spacer tight region, the amount of residual oxygen in the molten steel is high, so the residual oxygen varies, and Al 2 O in the generated inclusions is varied.
3 There was also a problem that the morphology of inclusions varied due to changes in concentration, and it was difficult to make the inclusions fine during hot rolling.
【0005】そこで、溶鋼の脱酸方法を改善して、特公
昭63−18646号公報は、真空アーク脱ガス装置に
てCaO−SiO2 系スラグやフラックスを用い、溶鋼
中に添加されるAl総量を10g/ton以下に規制す
る方法を、又特開昭62−203647号公報は、精練
容器に使用する耐火物を非Al2 O3 系にする方法を提
案した。In view of this, an improved method for deoxidizing molten steel is disclosed in Japanese Examined Patent Publication No. Sho 63-18646, in which the total amount of Al added to molten steel is changed by using a CaO—SiO 2 slag or flux in a vacuum arc degasser. To 10 g / ton or less, and Japanese Patent Laid-Open No. 62-203647 proposed a method in which the refractory used in the refining vessel is a non-Al 2 O 3 system.
【0006】しかしながら、真空アーク脱ガス装置を用
いた溶鋼処理では、低酸素化は可能となったが、溶鋼中
炭素の脱酸力がAlより強まり、耐火物やスラグ等に含
まれるAl2 O3 がCにより還元され、溶鋼中の残存A
l濃度が増加した。この溶存Alは、処理後の溶鋼温度
低下、及び連続鋳造時に酸素と結びつき、再びAl2O3
となり、熱延時に非延性な介在物として鋳片に残留す
る問題が生じた。その際、たとえ非Al2 O3 系耐火物
を用いても、転炉スラグの混入や、添加合金中のAlに
起因してスラグ中にAl2 O3 が存在することは不可避
であり、連続鋳造におけるタンディッシュ内溶鋼の残存
Al濃度を低位にすることは難しかった。However, in the molten steel treatment using the vacuum arc degassing apparatus, it was possible to reduce oxygen, but the deoxidizing power of carbon in the molten steel became stronger than that of Al, and Al 2 O contained in refractory materials, slag, etc. 3 is reduced by C, remaining A in molten steel
l concentration increased. This dissolved Al is combined with oxygen in the molten steel temperature decrease after the treatment and continuous casting, and again Al 2 O 3
Therefore, there is a problem that non-ductile inclusions remain in the slab during hot rolling. At that time, even if a non-Al 2 O 3 system refractory is used, it is unavoidable that Al 2 O 3 is present in the slag due to mixing of converter slag and Al in the additive alloy, It was difficult to lower the residual Al concentration of the molten steel in the tundish during casting.
【0007】また、上記以外の溶鋼脱酸改善を施した介
在物調整方法として、特開昭53−76916号公報
は、「Ar吹込みによる取鍋精錬法を採用して酸素の混
入を規制すると共に、高融点のCaC2 等を含む還元性
スラグに、滓化促進のため低融点のアルカリ金属弗化
物、酸化物、アルカリ土類金属弗化物を5〜30%添加
した合成スラグを用いて脱酸した後、Mg、Ca、T
i、Al、Zrを適量添加して延性の良好な介在物にす
る方法」、あるいは特公昭57−35234号公報は、
「Al完全規制の下(5g/溶鋼ton以下)で、Ca
O含有フラックスを溶鋼に吹き込んで予備脱酸した後、
Ca、Mg、または、REMを微量吹き込んで延性の良
好な介在物にする方法を開示している。Further, as a method of adjusting inclusions for improving deoxidation of molten steel other than the above, Japanese Patent Laid-Open No. 53-76916 discloses, "Adopting a ladle refining method by Ar blowing to regulate oxygen mixture. At the same time, a reducing slag containing high-melting point CaC 2 or the like is added with a synthetic slag obtained by adding 5 to 30% of a low-melting point alkali metal fluoride, oxide, or alkaline earth metal fluoride to promote slag formation. After acidification, Mg, Ca, T
i, Al, and Zr are added in appropriate amounts to form inclusions having good ductility ", or Japanese Patent Publication No. 57-35234.
"Under full Al regulation (5g / mol steel ton or less),
After pre-deoxidizing by blowing O-containing flux into the molten steel,
It discloses a method in which a small amount of Ca, Mg, or REM is blown into an inclusion having good ductility.
【0008】しかしながら、上記方法では、介在物形態
の調整に使用する脱酸元素の活性度が高過ぎ、該脱酸元
素の添加量が介在物の形態に大きく影響して延性の良好
な介在物を安定して生成させることが困難であった。ま
た、予備脱酸に使用したCaC2 等を含む還元性スラグ
やCaO含有フラックスは、溶鋼に巻込まれたり、吹込
まれた際には完全に浮上できず、その後の脱酸生成物と
凝集、合体せずにかえって硬質な介在物になってしまう
という問題があった。However, in the above method, the activity of the deoxidizing element used for adjusting the morphology of the inclusions is too high, and the addition amount of the deoxidizing element has a great influence on the morphology of the inclusions, and the inclusions having good ductility. It was difficult to stably generate In addition, the reducing slag containing CaC 2 and the like used for preliminary deoxidation and the CaO-containing flux cannot be completely floated up when they are caught in or blown into the molten steel, and they are aggregated with the subsequent deoxidized product and coalesced. There was a problem that it became a hard inclusion rather than doing it.
【0009】また、特開平4−110413号公報は、
「溶鋼中のAl総量を溶鋼トン当たり0.010kg以
下にし、アーク加熱式取鍋精錬設備で、スラグ組成を
(CaO/SiO2 )=0.7〜0.9、Al2 O3 ≦
10%として溶鋼を処理した後、連続鋳造設備にて鋳型
内、及び、凝固末期で電磁撹拌しながら連続鋳造を行う
方法を提案した。これは、Al量を低位に保ち、スラグ
組成をCaO/SiO2=0.7〜0.9とすることに
よって、Al2 O3 ≦10%とaAl2O3 (Al2O3 活
量)の上限を決め、Al2 O3 濃度の高い介在物の生成
を防止する技術である。Further, Japanese Patent Laid-Open No. 4-110413 discloses
"The total amount of Al in molten steel is 0.010 kg or less per ton of molten steel, and the slag composition is (CaO / SiO 2 ) = 0.7 to 0.9 and Al 2 O 3 ≤ in an arc heating type ladle refining equipment.
A method has been proposed in which, after treating molten steel to 10%, continuous casting is performed in a mold in a continuous casting facility and with electromagnetic stirring at the end of solidification. This keeps the amount of Al in the lower, the upper limit of by the slag composition and CaO / SiO 2 = 0.7~0.9, Al 2 O 3 ≦ 10% and a Al2O3 (Al 2 O 3 activity) To prevent the formation of inclusions having a high Al 2 O 3 concentration.
【0010】しかしながら、上記スラグのaAl2O3 が大
きいため、溶鋼中の残存酸素は高く、タンディッシュ内
溶鋼の酸素濃度が20ppmを越え、介在物量がかえっ
て増えた。加えて、タンディッシュ内で溶鋼中の残存A
l濃度が低位になりやすく、そのため、凝固時に生成す
る介在物は、SiO2 濃度の高い硬質な介在物となり、
熱延時に変形せず、熱延後の線材中に1μm以上の大き
さで存在した。However, since the a Al2O3 of the slag is large, the residual oxygen in the molten steel is high, the oxygen concentration of the molten steel in the tundish exceeds 20 ppm, and the amount of inclusions rather increases. In addition, the residual A in the molten steel in the tundish
The l-concentration tends to be low, so that the inclusions generated during solidification become hard inclusions with a high SiO 2 concentration,
It was not deformed during hot rolling and was present in the wire rod after hot rolling in a size of 1 μm or more.
【0011】さらに、溶鋼の酸素量低減方法として、特
開昭60−184617号公報は「溶鋼中のAl総量を
溶鋼トン当たり10g以下にし、炉外精錬時のスラグ組
成をCaO−SiO2 −Al2 O3 系で、(CaO/S
iO2 )≧1.5、(FeO+MnO)≦3%とすると
共に、介在物の組成調整の観点から、スラグ中のAl 2
O3 量の上限として3.0≧(CaO/SiO2 )≧
1.5のとき、Al2 O 3 ≦16%−4(CaO/Si
O2 )%、(CaO/SiO2 )>3.0のとき、Al
2 O3 ≦4%とし、かつ精錬済の溶鋼中Al総量を10
g/ton(溶鋼)以下にすることを開示している。こ
の方法によれば、スラグが(CaO/SiO2 )≧1.
5でスラグのaSiO2が低いので溶鋼の酸素量は低下し、
また、スラグ中のAl2 O3 量をCaO/SiO2 の上
昇にともない上限を低下させるようにしているので、鋼
中のAl濃度の上昇は抑えられ、Al2 O3 濃度の高い
介在物生成は防止できる。Further, as a method for reducing the oxygen content of molten steel,
KAISHO No. 60-184617 discloses "The total amount of Al in molten steel is
10 g or less per ton of molten steel, slag assembly for refining outside the furnace
Composition of CaO-SiO2 -Al2 OThree System, (CaO / S
iO2 ) ≧ 1.5, (FeO + MnO) ≦ 3%
In both cases, from the viewpoint of adjusting the composition of inclusions, Al in the slag 2
OThree The upper limit of the amount is 3.0 ≧ (CaO / SiO2 ) ≧
When 1.5, Al2 O Three ≤16% -4 (CaO / Si
O2 )%, (CaO / SiO2 )> 3.0, Al
2 OThree ≦ 4%, and the total amount of Al in the molten steel after refining is 10
It is disclosed that the content is set to g / ton (molten steel) or less. This
According to the method of slag, slag (CaO / SiO2 ) ≧ 1.
5 of slag aSiO2Is low, the oxygen content of the molten steel is reduced,
In addition, Al in the slag2 OThree CaO / SiO2 upon
As the upper limit is lowered with the rise,
The increase of Al concentration in the2 OThree High concentration
The formation of inclusions can be prevented.
【0012】しかしながら、スラグ中のCaO量が高
く、SiO2 、Al2 O3 量が低いため、スラグの融点
が上昇し、滓化性が悪く、精錬中のスラグ−溶鋼間の反
応が十分には進行しない。また、スラグが精錬中に溶鋼
内に巻込まれ、浮上できず鋳片に残存し介在物となった
場合、介在物はCaO量が高く、非延性で硬質になる問
題がある。このスラグの滓化性を良くするため、CaF
2 等の弗化物を混合することも考えられるが、弗化物を
混合すると、耐火物の溶損が増加し、耐火物が非延性で
硬質な介在物として鋼中に入ってしまう問題がある。さ
らに、精錬済の溶鋼中Al総量を10g/ton(溶
鋼)以下としているが、タンディッシュ内での溶鋼中の
酸素濃度に対する溶鋼の残存Al濃度が高く、鋼中にA
l2 O3 濃度の高い介在物が生成する恐れがあった。However, since the amount of CaO in the slag is high and the amounts of SiO 2 and Al 2 O 3 are low, the melting point of the slag increases and the slagification property is poor, and the reaction between the slag and the molten steel during refining is sufficient. Does not progress. Further, when the slag is caught in the molten steel during refining and cannot be floated and remains in the slab to become inclusions, the inclusions have a high CaO content and become non-ductile and hard. In order to improve the slag-forming property of this slag, CaF
It is possible to mix fluorides such as 2, but when fluorides are mixed, there is a problem that the melting loss of the refractory increases and the refractory enters the steel as a non-ductile and hard inclusion. Further, although the total amount of Al in the molten steel after refining is set to 10 g / ton (molten steel) or less, the residual Al concentration in the molten steel is high with respect to the oxygen concentration in the molten steel in the tundish, and
There was a risk that inclusions having a high concentration of l 2 O 3 would be formed.
【0013】[0013]
【発明が解決しようとする課題】本発明は、かかる事情
を鑑み、鋼材中の全酸素量を従来より低減して非延性の
介在物を少なくし、高強度であるが加工伸延性及び耐時
効性に優れた高炭素鋼材及びその製造方法を提供するこ
とを目的としている。SUMMARY OF THE INVENTION In view of such circumstances, the present invention reduces the total oxygen content in the steel material as compared with the prior art to reduce non-ductile inclusions, and has a high strength, but also a work elongation and aging resistance. An object of the present invention is to provide a high carbon steel material having excellent properties and a method for producing the same.
【0014】[0014]
【課題を解決するための手段】発明者は、上記目的を達
成するため、前述した従来技術を踏まえて鋭意研究を行
い、脱酸生成物として硬質のAl2 O3 系介在物を生成
させないためには、鋼中のAl濃度を低減させるだけで
は駄目で、常に溶存酸素量とのバランスを配慮する必要
があることを痛感した。しかも、酸素に関しては、脱酸
後に大気からピックアップする酸素も考慮しなければ、
特に、連続鋳造で凝固時に析出してくる脱酸生成物の形
態調整は困難であることを確認し、本発明をするに至っ
た。 すなわち、本発明は、C:0.5〜1.0wt
%、Si:0.15〜0.50wt%、Mn:0.3〜
0.9wt%、P:<0.020wt%、S:<0.0
20wt%で残部鉄及び不可避的不純物からなる炭素鋼
線材において、上記線材中の全酸素濃度が20ppm以
下、残存Al濃度が0.4ppm以上2.0ppm以
下、窒素が40ppm以下であることを特徴とする伸線
加工性及び耐時効性に優れた炭素鋼線材である。また、
本発明は、燐及び硫黄分をそれぞれ0.020wt%以
下に低減した予備処理溶銑を転炉で脱炭吹錬し、取鍋に
出鋼するに際し、Al含有量が0.01wt%以下のF
e−Si及び/又はFe−Mnで脱酸すると共に、Ca
O−SiO2 −Al2 O3 系フラックスを添加してスラ
グのSiO2 活量を0.10以下として受鋼し、脱ガス
設備で該溶鋼に不活性ガスを吹込み撹拌精錬することを
特徴とする伸線加工性及び耐時効性に優れた炭素鋼線材
の製造方法であり、さらに、上記不活性ガスの吹込み撹
拌を、溶鋼中の酸素が10ppm以下まで継続すること
を特徴とする伸線加工性及び耐時効性に優れた炭素鋼線
材の製造方法でもある。In order to achieve the above-mentioned object, the inventor has conducted diligent research based on the above-mentioned prior art, in order to prevent generation of hard Al 2 O 3 inclusions as deoxidation products. However, I realized that it is not enough to reduce the Al concentration in the steel, and it is always necessary to consider the balance with the amount of dissolved oxygen. Moreover, regarding oxygen, if you do not consider oxygen picked up from the atmosphere after deoxidation,
In particular, it has been confirmed that it is difficult to control the morphology of the deoxidized product that precipitates during solidification in continuous casting, and the present invention has been completed. That is, in the present invention, C: 0.5 to 1.0 wt.
%, Si: 0.15 to 0.50 wt%, Mn: 0.3 to
0.9 wt%, P: <0.020 wt%, S: <0.0
A carbon steel wire rod composed of the balance iron and unavoidable impurities at 20 wt%, characterized in that the total oxygen concentration in the wire rod is 20 ppm or less, the residual Al concentration is 0.4 ppm or more and 2.0 ppm or less, and nitrogen is 40 ppm or less. It is a carbon steel wire rod having excellent wire drawing workability and aging resistance. Also,
According to the present invention, when the pre-treated hot metal containing phosphorus and sulfur reduced to 0.020 wt% or less is decarburized and blown in a converter and tapped into a ladle, an F content of 0.01 wt% or less in Al content is obtained.
While deoxidizing with e-Si and / or Fe-Mn, Ca
O-SiO 2 -Al 2 O 3 based flux to be added to受鋼the SiO 2 activity of slag as 0.10, characterized in that the blow stirred refining inert gas into solution steel degassing facility The method for producing a carbon steel wire rod having excellent wire drawing workability and aging resistance, further comprising: continuously stirring the above-described inert gas by blowing until oxygen in molten steel is 10 ppm or less. It is also a method for producing a carbon steel wire rod having excellent wire workability and aging resistance.
【0015】[0015]
【作用】本発明では、C:0.5〜1.0wt%、S
i:0.15〜0.50wt%、Mn:0.3〜0.9
wt%、P:<0.020wt%、S:<0.020w
t%で残部鉄及び不可避的不純物からなる炭素鋼線材に
おいて、上記線材中の全酸素濃度が20ppm以下、残
存Al濃度が0.4ppm以上2.0ppm以下、窒素
が40ppm以下であるようにしたので、線材中に硬質
なAl2 O3 介在物あるいは1μm以上のSiO2 介在
物が存在せず、伸線加工性及び耐時効性が著しく向上し
た高強度の高炭素鋼線材となる。その結果、この線材を
用いて伸線加工工程でも断線せず、極細線の製造が安定
して行えるようになった。In the present invention, C: 0.5-1.0 wt%, S
i: 0.15 to 0.50 wt%, Mn: 0.3 to 0.9
wt%, P: <0.020 wt%, S: <0.020w
In the carbon steel wire rod composed of the balance iron and unavoidable impurities at t%, the total oxygen concentration in the wire rod was 20 ppm or less, the residual Al concentration was 0.4 ppm or more and 2.0 ppm or less, and the nitrogen was 40 ppm or less. In addition, there is no hard Al 2 O 3 inclusions or SiO 2 inclusions having a size of 1 μm or more in the wire, and the wire is a high-strength, high-carbon steel wire with markedly improved drawability and aging resistance. As a result, it became possible to stably manufacture an ultrafine wire using this wire without breaking even in the wire drawing process.
【0016】また、本発明では、燐及び硫黄分をそれぞ
れ0.020wt%以下に低減した予備処理溶銑を転炉
で脱炭吹錬し、取鍋に出鋼するに際し、Al含有量が
0.01wt%以下のFe−Si及び/又はFe−Mn
で脱酸すると共に、CaO−SiO2 −Al2 O3 系フ
ラックスを添加してスラグのSiO2 活量を0.10以
下として受鋼し、脱ガス設備で該溶鋼に不活性ガスを吹
込み撹拌精錬し、さらに、上記不活性ガスの吹込み撹拌
を、溶鋼中の酸素が10ppm以下まで継続するように
したので、溶鋼中の酸素濃度が容易に低減することが可
能となり、前記した延性のない介在物を低減した極細線
用高炭素鋼材を供給できるようになる。Further, in the present invention, when the pretreated hot metal having a phosphorus content and a sulfur content each reduced to 0.020 wt% or less is decarburized and blown in a converter and tapped into a ladle, the Al content is 0. Fe-Si and / or Fe-Mn of 01 wt% or less
In addition to deoxidation, CaO-SiO 2 -Al 2 O 3 based flux to be added to受鋼the SiO 2 activity of slag as 0.10, blowing an inert gas into solution steel degassing facility Since the refining by stirring and the stirring by blowing of the above-mentioned inert gas are continued until the oxygen in the molten steel is 10 ppm or less, the oxygen concentration in the molten steel can be easily reduced, and the ductility It becomes possible to supply high carbon steel materials for extra fine wires with reduced inclusions.
【0017】以下に、本発明に係る線材の化学組成を限
定した理由を説明する。 C:Cは、線材の伸線加工後の強度を確保するために少
なくとも0.50wt%以上必要であり、一方1.0w
t%を越えると粗大な初析セメンタイトが析出し、脆化
するので、0.5〜1.0wt%とした。 Si:Siは、脱酸に有効な元素であり、その効果を発
揮させるには0.15wt%以上必要であり、一方、過
多な添加は、SiO2 系介在物を増加して伸線加工性を
損なうので、0.50wt%以下とした。 Mn:Mnも脱酸に有効で、かつ延性劣化を助長するS
をMnSとして固定し、さらに焼入れ性を確保して強度
を出す観点から下限を0.30wt%とした。しかし、
過多の添加は、焼入れ過剰となり、線材組織にミクロな
マルテンサイトを生じ、伸線加工性を低下させるので
0.9wt%を上限とする。 P,S:P、Sは,それらが高いと伸線加工性が悪化す
るので、少ないのが好ましく、P<0.020wt%、
S<0.020wt%に抑えた。 Al:線材中のAl濃度に上下限を設けたことが、本発
明の重要ポイントの一つである。Al2 O3 介在物を低
減するため、溶鋼中のAlを総量規制することは従来か
ら行われていたが、本発明では、特に少なく残存Al濃
度で0.4ppm以上2.0ppm以下に限定した。そ
の理由は、発明者らが開発した微量溶存Al量分析技術
を用いて溶存Al量を種々変化させた線材を熱延し、1
μm幅以上の介在物の存在を調査して得た結果による。
すなわち、図2から明らかなように、残存Alが0.4
ppm〜2.0ppmの範囲をはずれると、上記介在物
の存在が増加したからである。図2の結果が得られたの
は、推定であるが、残存Alが0.4ppm未満では、
介在物中のSiO2 濃度が上昇し、残存Alが2.0p
pmを超えると、介在物中のAl2 O3 濃度が上昇し、
いずれの場合も介在物の熱間圧延時の変形能が低下した
ためと考えられる。The reasons for limiting the chemical composition of the wire according to the present invention will be described below. C: C is required to be at least 0.50 wt% or more in order to secure the strength of the wire rod after wire drawing, while 1.0 w
If it exceeds t%, coarse pro-eutectoid cementite is precipitated and becomes brittle, so the content was made 0.5 to 1.0 wt%. Si: Si is an element effective for deoxidation, and 0.15 wt% or more is required to exert its effect. On the other hand, excessive addition increases SiO 2 inclusions and wire drawing workability. Therefore, it is set to 0.50 wt% or less. Mn: S is also effective for deoxidation and promotes deterioration of ductility.
Was fixed as MnS, and the lower limit was set to 0.30 wt% from the viewpoint of securing hardenability and producing strength. But,
If it is added in excess, quenching becomes excessive, and micro martensite occurs in the wire structure, which deteriorates the wire drawing workability, so the upper limit is 0.9 wt%. P, S: P, S is preferable if they are high, so wire drawing workability deteriorates.
It was suppressed to S <0.020 wt%. Al: One of the important points of the present invention is to set the upper and lower limits on the Al concentration in the wire. In order to reduce Al 2 O 3 inclusions, the total amount of Al in molten steel has been conventionally regulated, but in the present invention, the residual Al concentration is particularly small and is limited to 0.4 ppm or more and 2.0 ppm or less. . The reason is that a wire rod having various amounts of dissolved Al is hot-rolled using the trace amount dissolved Al amount analysis technique developed by the inventors, and
Based on the results obtained by investigating the presence of inclusions having a width of μm or more.
That is, as is clear from FIG. 2, the residual Al is 0.4
This is because the presence of the above inclusions increased when the concentration was outside the range of ppm to 2.0 ppm. It is estimated that the result of FIG. 2 was obtained, but when the residual Al is less than 0.4 ppm,
The SiO 2 concentration in the inclusions increased and the residual Al remained 2.0p.
When it exceeds pm, the Al 2 O 3 concentration in the inclusions increases,
In all cases, it is considered that the deformability of the inclusions during hot rolling decreased.
【0018】なお、鋼中のAl濃度を低位に保つには、
Alの混入源として脱酸材であるFe−Si、Fe−M
n等の合金は、高純度(Al<0.01%)のものを用
いるのがよく、また、耐火物としてAl2 O3 質のもの
は避けるのが望ましい。 O:Oも本発明の重要ポイントのひとつで、線材中の残
存酸素濃度を20ppm以下、好ましくは15ppmと
した。その根拠は、発明者が、Oを微量含む炭素鋼線材
を一定条件で伸線加工し、断線回数を調査した結果によ
る。図1から明らかなように、Oが20ppmを超える
と断線回数指数の増加傾向が大となり、また該指数も通
常許容される5を超えるからである。In order to keep the Al concentration in steel at a low level,
Fe-Si and Fe-M, which are deoxidizing materials, as a source for mixing Al
As the alloy such as n, it is preferable to use a high-purity (Al <0.01%) alloy, and it is desirable to avoid a refractory alloy of Al 2 O 3 quality. O: O is also one of the important points of the present invention, and the residual oxygen concentration in the wire is set to 20 ppm or less, preferably 15 ppm. The grounds for this are the results of the inventors' investigation of the number of wire breaks by wire-drawing a carbon steel wire containing a small amount of O under certain conditions. As is clear from FIG. 1, when O exceeds 20 ppm, the disconnection number index tends to increase, and the index also exceeds 5 which is usually allowable.
【0019】そして、酸素を上記限定量にした線材を鋳
造することも本発明の重要ポイントで、転炉出鋼後の溶
鋼に2次精錬を行い、鋳造用タンディッシュ内で溶鋼の
酸素濃度が10ppm以下に維持されることが必要であ
る。鋳造時に溶鋼が酸素をピックアップすることを配慮
しての措置である。そのためには、Si脱酸でスラグ中
のaSiO2を下げてスラグ−溶鋼反応により鋼中の酸素量
を低下させる方法が好ましい。本発明では、不活性ガス
の撹拌を行う2次精錬において、CaO−SiO2 −A
l2 O3 系スラグを用い、CaO/SiO2 を大きくす
ることによりaSiO2を下げ、溶存酸素濃度をタンディッ
シュ内溶鋼で10ppm以下に低下させることができ
た。 N:Nは、その濃度が高いと、伸線後の熱処理による時
効後の伸びが低下するので、40ppm以下とした。そ
の根拠を図4に示すが、5.5mmの素材を0.15m
mφ線材に加工した後、150℃で30minの熱処理
による時効後の伸び(RA,単位%)とN濃度との関係
は、Nが40ppm以上になると時効後の伸びが大きく
低下していることによる。It is also an important point of the present invention to cast a wire rod having the above-mentioned limited amount of oxygen, and the molten steel after the steel is discharged from the converter is subjected to secondary refining so that the oxygen concentration of the molten steel is increased in the casting tundish. It should be maintained below 10 ppm. This is a measure considering that the molten steel picks up oxygen during casting. For that purpose, a method of lowering a SiO2 in the slag by deoxidizing Si to reduce the amount of oxygen in the steel by a slag-molten steel reaction is preferable. In the present invention, in the secondary refining to perform agitation of the inert gas, CaO-SiO 2 -A
using l 2 O 3 slag, lowered a SiO2 by increasing the CaO / SiO 2, it could be reduced to 10ppm or less in the tundish molten steel a dissolved oxygen concentration. N: N is 40 ppm or less, because if the concentration is high, the elongation after aging due to the heat treatment after wire drawing decreases. The basis is shown in Fig. 4, but a 5.5 mm material is 0.15 m long.
The relationship between the elongation (RA, unit%) after aging and the N concentration after heat treatment at 150 ° C. for 30 minutes after processing into mφ wire rod is because the elongation after aging greatly decreases when N is 40 ppm or more. .
【0020】なお、線材の溶存Al濃度は、鉄分離−電
気加熱原子吸光法により分析して求めた。The dissolved Al concentration of the wire was determined by iron separation-electric heating atomic absorption spectrometry.
【0021】[0021]
【実施例】まず、溶銑予備処理によって P:<0.0
20wt%、S:<0.020wt%に低減した溶銑1
80トンを、複合吹錬転炉にてC含有量 0.7wt%
まで酸素吹錬した。出鋼に際し、Al含有量(0.01
%以下)の少ないFe−Siを500kg、及びFe−
Mnを1000kg添加して脱酸すると共に、他の成分
調整を行った。EXAMPLE First, P: <0.0 by hot metal pretreatment.
20 wt%, S: <0.020 wt% reduced hot metal 1
80 tons of C content 0.7wt% in the composite blowing converter
It was blown with oxygen. When tapping steel, Al content (0.01
% Fe or less of Fe-Si, and Fe-
1000 kg of Mn was added to deoxidize, and other components were adjusted.
【0022】次に、該溶鋼をAl2 O3 を含有していな
い耐火物を内張した取鍋に受鋼した。また、受鋼時にC
aO−SiO2 −Al2 O3 系フラックスを2000k
g添加し、スラグのSiO2 活量を0.10以下に調整
した。なお、耐火物としてはスラグラインにマグネシア
・カーボンレンガ、その他の壁や敷にジルコン流し込み
材を用いた。Next, the molten steel was received in a ladle lined with a refractory containing no Al 2 O 3 . Also, when steel is received, C
aO-SiO 2 -Al 2000k a 2 O 3 based flux
g was added and the SiO 2 activity of the slag was adjusted to 0.10. As the refractory material, magnesia carbon brick was used for the slag line, and zircon pouring material was used for other walls and floors.
【0023】その後、該取鍋をVOD設備に入れ、そこ
で溶鋼中にArガスを吹込み撹拌精錬処理を行い、該処
理後の溶鋼を連続鋳造設備にて鋳造した。その際、タン
ディッシュ内の溶鋼からサンプルを採取して酸素分析し
たところ、酸素は8ppmであった。この鋳片を熱間圧
延にて5.5mmφまで圧延され、線材中の1μm幅以
上の非金属介在物個数を公知のJIS法で測定し、引き
続き伸線加工して0.15mmφの最終製品にした。Thereafter, the ladle was placed in a VOD facility, Ar gas was blown into the molten steel to perform stirring and refining treatment, and the molten steel after the treatment was cast in a continuous casting facility. At that time, when a sample was taken from the molten steel in the tundish and analyzed for oxygen, oxygen was 8 ppm. This slab is rolled by hot rolling to 5.5 mmφ, the number of non-metallic inclusions having a width of 1 μm or more in the wire is measured by a known JIS method, and then wire drawing is performed to obtain a final product of 0.15 mmφ. did.
【0024】[0024]
【表1】 [Table 1]
【0025】表1に、本発明例と比較例としての線材
で、介在物、断線回数指数や時効後のRA(伸び)を調
査した結果を示す。本発明に係る線材では、5.5mm
φ線材中の1μm以上の介在物個数指数は5以下と非常
に低位であった。その結果、0.15mmφの極細線ま
での伸線加工工程での断線も大きく低減されている。ま
た、耐時効性にも優れていることがわかる。Table 1 shows the results of investigating inclusions, wire breakage index and RA (elongation) after aging for the wire rods of the present invention and comparative examples. In the wire rod according to the present invention, 5.5 mm
The index of the number of inclusions of 1 μm or more in the φ wire material was 5 or less, which was a very low level. As a result, disconnection in the drawing process up to the ultrafine wire of 0.15 mmφ is greatly reduced. It is also found that the aging resistance is also excellent.
【0026】最後に、これらのデータから線材中の残存
Al濃度と断線回数指数との関係を整理し、図3に示し
ておく。図3より、線材の残存Al濃度が2.0ppm
より大きいと、熱間圧延後の5.5mmφ線材中の幅1
μm以上の介在物個数は大きく増加し、断線回数指数は
増大することが明らかである。望ましくは、Alを1.
0ppm以下にすれば、断線指数はより低下するよう
だ。一方、線材中の残存Al濃度が0.4ppm未満の
場合、熱間圧延後の5.5mmφ線材中の幅1μm以上
の介在物個数は大きく増大し、断線回数指数は増加し
た。Finally, the relationship between the residual Al concentration in the wire and the index of the number of wire breakages is summarized from these data and shown in FIG. From Fig. 3, the residual Al concentration of the wire rod is 2.0 ppm.
If it is larger, the width in the 5.5 mmφ wire rod after hot rolling is 1
It is clear that the number of inclusions having a size of μm or more greatly increases and the disconnection number index increases. Desirably, Al is 1.
If it is set to 0 ppm or less, the disconnection index seems to be lower. On the other hand, when the residual Al concentration in the wire rod was less than 0.4 ppm, the number of inclusions having a width of 1 μm or more in the 5.5 mmφ wire rod after hot rolling significantly increased, and the wire breakage index increased.
【0027】[0027]
【発明の効果】以上述べたように、本発明により、酸素
含有量が20ppm以下で、且つ熱延後の線材中の1μ
m幅以上の介在物量が少ない高炭素鋼材が溶製されるよ
うになり、その後の冷間引抜加工性(伸線加工性)及び
耐時効性に優れた高炭素鋼線材が得られるようになっ
た。As described above, according to the present invention, the oxygen content is 20 ppm or less, and 1 μm in the wire rod after hot rolling.
High carbon steel materials with a small amount of inclusions of m width or more came to be manufactured, and high carbon steel wire materials with excellent cold drawing workability (drawing workability) and aging resistance can be obtained. It was
【図1】図1は、全酸素濃度と5.5mmφ線材を0.
15mmφの極細線まで伸線した時の断線回数指数の関
係である。FIG. 1 shows the total oxygen concentration and 5.5 mmφ wire rod as 0.
It is the relationship of the number of wire breakage indexes when the wire is drawn up to a 15 mmφ ultrafine wire.
【図2】熱間圧延後の5.5mmφ線材の残存Al濃度
と線材中の1μm幅以上の介在物個数との関係である。FIG. 2 is a relationship between the residual Al concentration of a 5.5 mmφ wire after hot rolling and the number of inclusions having a width of 1 μm or more in the wire.
【図3】5.5mmφ線材の残存Al濃度とその線材を
0.15mmφの極細線まで伸線加工する工程での断線
回数指数との関係である。FIG. 3 is a relationship between the residual Al concentration of a 5.5 mmφ wire and the index of the number of wire breakages in the step of drawing the wire to an ultrafine wire of 0.15 mmφ.
【図4】0.15mmφ線材における150℃で30m
inの熱処理による時効後の伸び(RA)とN濃度との
関係である。[Fig. 4] 30m at 150 ° C in 0.15mmφ wire
It is a relationship between elongation (RA) after aging by heat treatment of in and N concentration.
Claims (3)
らなる炭素鋼線材において、 上記線材中の全酸素濃度が20ppm以下、残存Al濃
度が0.4ppm以上2.0ppm以下、窒素が40p
pm以下であることを特徴とする伸線加工性及び耐時効
性に優れた炭素鋼線材。1. C: 0.5 to 1.0 wt%, Si: 0.15 to 0.50 wt%, Mn: 0.3 to 0.9 wt%, P: <0.020 wt%, S: <0. In a carbon steel wire rod containing 0.020 wt% of the balance iron and inevitable impurities, the total oxygen concentration in the wire rod is 20 ppm or less, the residual Al concentration is 0.4 ppm or more and 2.0 ppm or less, and the nitrogen content is 40 p
A carbon steel wire rod excellent in wire drawing workability and aging resistance, which is characterized by being pm or less.
%以下に低減した予備処理溶銑を転炉で脱炭吹錬し、取
鍋に出鋼するに際し、 Al含有量が0.01wt%以下のFe−Si及び/又
はFe−Mnで脱酸すると共に、CaO−SiO2 −A
l2 O3 系フラックスを添加してスラグのSiO2 活量
を0.10以下として受鋼し、脱ガス設備で該溶鋼に不
活性ガスを吹込み撹拌精錬することを特徴とする伸線加
工性及び耐時効性に優れた炭素鋼線材の製造方法。2. A phosphorus content and a sulfur content each are 0.020 wt.
% Of the pre-treated hot metal reduced to less than or equal to 0.1% when decarburizing and blowing in a converter and tapping in a ladle, deoxidizing with Fe-Si and / or Fe-Mn with an Al content of 0.01 wt% or less. , CaO-SiO 2 -A
l 2 O 3 -based flux is added to the slag so that the SiO 2 activity of the slag is 0.10 or less and steel is received, and an inert gas is blown into the molten steel in a degassing facility to perform stirring refining. Of carbon steel wire with excellent heat resistance and aging resistance.
の酸素が10ppm以下まで継続することを特徴とする
請求項2記載の伸線加工性及び耐時効性に優れた炭素鋼
線材の製造方法。3. The carbon steel wire rod excellent in wire drawing workability and aging resistance as set forth in claim 2, characterized in that the stirring and blowing of the inert gas is continued until oxygen in the molten steel is 10 ppm or less. Production method.
Priority Applications (1)
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JP21620395A JP3536461B2 (en) | 1995-08-24 | 1995-08-24 | High carbon steel wire with excellent drawability and aging resistance |
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Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP21620395A JP3536461B2 (en) | 1995-08-24 | 1995-08-24 | High carbon steel wire with excellent drawability and aging resistance |
Publications (2)
Publication Number | Publication Date |
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JPH0959744A true JPH0959744A (en) | 1997-03-04 |
JP3536461B2 JP3536461B2 (en) | 2004-06-07 |
Family
ID=16684894
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Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2002275525A (en) * | 2001-03-16 | 2002-09-25 | Kawasaki Steel Corp | High carbon steel refining method |
KR100402012B1 (en) * | 1999-10-13 | 2003-10-17 | 주식회사 포스코 | Method of refining molten steel to cast small section billet for hard steel wir rods |
WO2007114100A1 (en) * | 2006-03-30 | 2007-10-11 | Kabushiki Kaisha Kobe Seiko Sho | Process for producing steel for high-carbon steel wire material with excellent drawability and fatigue characteristics |
JP2009052107A (en) * | 2007-08-28 | 2009-03-12 | Kobe Steel Ltd | Method for producing high-purity steel |
-
1995
- 1995-08-24 JP JP21620395A patent/JP3536461B2/en not_active Expired - Fee Related
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR100402012B1 (en) * | 1999-10-13 | 2003-10-17 | 주식회사 포스코 | Method of refining molten steel to cast small section billet for hard steel wir rods |
JP2002275525A (en) * | 2001-03-16 | 2002-09-25 | Kawasaki Steel Corp | High carbon steel refining method |
JP4639497B2 (en) * | 2001-03-16 | 2011-02-23 | Jfeスチール株式会社 | Method for refining high carbon steel |
WO2007114100A1 (en) * | 2006-03-30 | 2007-10-11 | Kabushiki Kaisha Kobe Seiko Sho | Process for producing steel for high-carbon steel wire material with excellent drawability and fatigue characteristics |
JP2009052107A (en) * | 2007-08-28 | 2009-03-12 | Kobe Steel Ltd | Method for producing high-purity steel |
Also Published As
Publication number | Publication date |
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