JP3001572B1 - High-strength, high-ductility ultrafine steel wire, stranded wire, and method for producing the same - Google Patents
High-strength, high-ductility ultrafine steel wire, stranded wire, and method for producing the sameInfo
- Publication number
- JP3001572B1 JP3001572B1 JP11057106A JP5710699A JP3001572B1 JP 3001572 B1 JP3001572 B1 JP 3001572B1 JP 11057106 A JP11057106 A JP 11057106A JP 5710699 A JP5710699 A JP 5710699A JP 3001572 B1 JP3001572 B1 JP 3001572B1
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- Prior art keywords
- steel wire
- strength
- less
- ultrafine steel
- wire
- Prior art date
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Classifications
-
- D—TEXTILES; PAPER
- D07—ROPES; CABLES OTHER THAN ELECTRIC
- D07B—ROPES OR CABLES IN GENERAL
- D07B1/00—Constructional features of ropes or cables
- D07B1/06—Ropes or cables built-up from metal wires, e.g. of section wires around a hemp core
- D07B1/0606—Reinforcing cords for rubber or plastic articles
- D07B1/066—Reinforcing cords for rubber or plastic articles the wires being made from special alloy or special steel composition
Landscapes
- Ropes Or Cables (AREA)
- Tires In General (AREA)
- Metal Extraction Processes (AREA)
Abstract
【要約】
【課題】 タイヤ、ホースなどの補強材として極めて高
い引張強さを有するとともに、優れた撚り加工性を有す
る極細鋼線及び撚り線を提供する。
【解決手段】 重量%で、C:0.8〜1.50%、
Si:0.10〜0.50%、Mn:0.20〜0.7
0%、Al:0.005%以下、P:0.02%以下、
S:0.02%以下、O:0.005%以下、N:0.
005%以下、5≦(Ca+Mg+REM)≦50pp
mに規制し、残部は鉄及び不可避不純物よりなり、0.
40mm以下の直径、4000MPa以上の引張強さ、
20%以上のキンク強度保持率、80%以上の引掛強度
を有し、かつC断面の中心より0.4×(極細鋼線の直
径)の位置のビッカース硬度(HVs)と中心のビッカ
ース硬度(HVc)の差(HVs−HVc)が30以下
であることを特徴とする高強度高延性極細鋼線。An object of the present invention is to provide an ultrafine steel wire and a stranded wire having extremely high tensile strength as a reinforcing material for a tire, a hose, and the like, and having excellent twistability. SOLUTION: In weight%, C: 0.8-1.50%,
Si: 0.10 to 0.50%, Mn: 0.20 to 0.7
0%, Al: 0.005% or less, P: 0.02% or less,
S: 0.02% or less, O: 0.005% or less, N: 0.
005% or less, 5 ≦ (Ca + Mg + REM) ≦ 50pp
m, the balance being iron and unavoidable impurities.
40mm or less diameter, 4000MPa or more tensile strength,
It has a kink strength retention of 20% or more, a hooking strength of 80% or more, and a Vickers hardness (HVs) at a position of 0.4 × (diameter of extra fine steel wire) from the center of the C section and a Vickers hardness at the center ( A high-strength and high-ductility ultrafine steel wire, wherein the difference (HVs-HVc) in HVc) is 30 or less.
Description
【0001】[0001]
【発明の属する技術分野】この発明は自動車タイヤのス
チールコード用に使用される高強度極細鋼線に関するも
のである。詳しくは、ダイスを用いて冷間伸線加工強化
された線径0.40mm以下 引張強さ4000MPa
級以上の極細鋼線及びそれを撚り加工した撚り線に関す
るものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-strength ultrafine steel wire used for a steel cord of an automobile tire. Specifically, the wire diameter is 0.40 mm or less reinforced by cold drawing using a die. Tensile strength 4000 MPa
The present invention relates to an ultrafine steel wire of grade or higher and a stranded wire obtained by twisting the wire.
【0002】[0002]
【従来の技術】自動車用スチールコード用極細鋼線に於
いてはタイヤの軽量化の要求から極細鋼線の高張力化に
対するニーズが最近益々高まっている。このため、従来
の強度レベルに比較して、特に撚り線工程での断線発生
が著しく高くなる傾向があり、スチールコードの高強度
化を達成する上での大きな障害となっている。2. Description of the Related Art In ultrafine steel wires for automobile steel cords, the need for higher tensile strength of ultrafine steel wires has recently increased more and more due to the demand for weight reduction of tires. For this reason, compared to the conventional strength level, the occurrence of disconnection particularly in the stranded wire process tends to be extremely high, which is a major obstacle to attaining high strength of the steel cord.
【0003】従来は高強度スチールコードの撚り線工程
の断線を抑制するためには、捻回試験の捻回−トルク曲
線において破断に至る途中で鋼線長手方向に割れが発生
するためにトルクが急激に低下する現象により検出され
るデラミネーションを抑制することが最も有効であると
されており、様々な技術が開発されてきた。[0003] Conventionally, in order to suppress breakage in the twisting process of a high-strength steel cord, in the torsion-torque curve of the torsion test, cracks are generated in the longitudinal direction of the steel wire on the way to breakage so that torque is reduced. It is considered to be most effective to suppress the delamination detected by the phenomenon of abrupt decrease, and various techniques have been developed.
【0004】例えば、特開平2−10220号公報、特
開平4−371549号公報に記載されているようにC
o等の特殊合金元素を添加して初析セメンタイト面積率
を制御する事等により、高強度極細鋼線の捻回試験時の
縦割れ、伸線断線を抑制することが可能であると記載さ
れている。[0004] For example, as described in JP-A-2-10220 and JP-A-4-371549,
It is described that by adding a special alloying element such as o to control the area ratio of proeutectoid cementite, it is possible to suppress longitudinal cracking and wire breakage during twisting test of high strength ultrafine steel wire. ing.
【0005】特開平6−336649号公報には、湿式
伸線工程において仕上げダイスを2つのダイスに分割し
てダブルダイスとし、第一仕上げダイスの入口、出口お
よび第二仕上げダイスの入口を湿式潤滑することにより
加工発熱を抑制し、デラミネーションの発生を防止する
ことが可能であると記載されている。Japanese Patent Application Laid-Open No. Hei 6-336649 discloses that in a wet drawing process, a finishing die is divided into two dies to form a double die, and the inlet and outlet of the first finishing die and the inlet of the second finishing die are wet-lubricated. It is described that by doing so, it is possible to suppress heat generation during processing and prevent the occurrence of delamination.
【0006】特開平8−120407号公報には、パー
ライト中の炭化物の平均粒径を10〜50nmにするこ
とにより高強度鋼線においてデラミネーションを抑制
し、捻回値を向上させることが可能であると記載されて
いる。JP-A-8-120407 discloses that by setting the average particle size of carbide in pearlite to 10 to 50 nm, it is possible to suppress delamination in a high-strength steel wire and improve the torsion value. It is stated that there is.
【0007】[0007]
【発明が解決しようとする課題】しかしながら、実際の
撚り線工程では特開平8−260096号公報などに記
載されているように捻回試験でデラミネーションが発生
しなくとも撚り線工程で断線が発生することが日常的に
経験されており、特に4000MPa以上の強度ではそ
の傾向が顕著である。つまりデラミネーションを抑制す
ることが4000MPa以上の高強度スチールコードの
撚り加工性を確保するための必要十分条件ではないのが
実態である。本発明は以上のような現状に着目し、タイ
ヤ、ホースなどの補強材として極めて高い引張強さを有
するとともに、優れた撚り加工性を有する極細鋼線及び
撚り線を提供しようとするものである。However, in the actual stranded wire process, disconnection occurs in the stranded wire process even if no delamination occurs in the twist test as described in Japanese Patent Application Laid-Open No. Hei 8-26009. Has been experienced on a daily basis, especially at a strength of 4000 MPa or more. In other words, in reality, suppression of delamination is not a necessary and sufficient condition for ensuring the twistability of a high-strength steel cord of 4000 MPa or more. The present invention focuses on the current situation as described above, and aims to provide an ultrafine steel wire and a stranded wire having extremely high tensile strength as a reinforcing material for tires, hoses, and the like, and having excellent twistability. .
【0008】[0008]
【課題を解決するための手段】前述の課題を解決するこ
とが可能となる本発明に係る高強度高延性極細鋼線及び
撚り線の構成は重量%で、C:0.8〜1.50%、S
i:0.10〜0.50%、Mn:0.20〜0.70
%、Al:0.005%以下、P:0.02%以下、
S:0.02%以下、O:0.005%以下、N:0.
005%以下、 5≦(Ca+Mg+REM)≦50ppm に規制し、残部は鉄及び不可避不純物よりなり、0.4
0mm以下の直径、4000MPa以上の引張強さ、2
0%以上のキンク強度保持率、80%以上の引掛強度を
有し、かつC断面の中心より0.4×(極細鋼線の直
径)の位置のビッカース硬度(HVs)と中心のビッカ
ース硬度(HVc)の差(HVs−HVc)が30以下
であることを特徴とする高強度高延性極細鋼線。Means for Solving the Problems The constitution of the high-strength, high-ductility ultrafine steel wire and the stranded wire according to the present invention, which can solve the above-mentioned problems, is C: 0.8 to 1.50 by weight%. %, S
i: 0.10 to 0.50%, Mn: 0.20 to 0.70
%, Al: 0.005% or less, P: 0.02% or less,
S: 0.02% or less, O: 0.005% or less, N: 0.
005% or less, 5 ≦ (Ca + Mg + REM) ≦ 50 ppm, with the balance being iron and unavoidable impurities.
0 mm or less diameter, 4000 MPa or more tensile strength, 2
It has a kink strength retention of 0% or more, a hooking strength of 80% or more, and a Vickers hardness (HVs) at a position of 0.4 × (diameter of extra fine steel wire) from the center of the C section and a Vickers hardness at the center ( A high-strength and high-ductility ultrafine steel wire, wherein the difference (HVs-HVc) in HVc) is 30 or less.
【0009】また前述の極細鋼線に於いて、屈曲値が8
0回以上を有する事を特徴とする高強度高延性極細鋼
線。尚、屈曲値とは極細鋼線の一端を極細鋼線の直径の
5倍の半径の円弧を有した1対のつかみ具に固定し、更
に極細鋼線の他端に引張破断荷重の1%の荷重を負荷
し、円弧に沿って90度づつ順逆方向に交互に繰り返し
曲げたときの破断までの繰り返し回数のことである。In the above-mentioned ultrafine steel wire, the bending value is 8
A high-strength, high-ductility ultrafine steel wire characterized by having zero or more turns. The bending value means that one end of the ultrafine steel wire is fixed to a pair of grips having an arc having a radius five times the diameter of the ultrafine steel wire, and the other end of the ultrafine steel wire is 1% of the tensile breaking load. This is the number of repetitions up to the fracture when bending is repeated alternately in the forward and reverse directions by 90 degrees along the arc while applying the load of.
【0010】これらの極細鋼線を撚り加工したものであ
ることを特徴とする撚り線に要旨がある。[0010] There is a gist of a stranded wire, which is obtained by twisting these ultrafine steel wires.
【0011】また、仕上げ伸線工程での鋼線とダイスの
間の摩擦係数を0.07以下とすること、更に伸線加工
途中に極細鋼線に捻り矯直加工をすることを特徴とする
上記高強度高延性極細鋼線の製造方法である。[0011] Further, the friction coefficient between the steel wire and the die in the finishing wire drawing step is set to 0.07 or less, and furthermore, the ultra-fine steel wire is subjected to a straightening process during the wire drawing process. A method for producing the high-strength, high-ductility ultrafine steel wire.
【0012】[0012]
【発明の実施の形態】まず、成分限定理由について述べ
る。本発明はパテンティング熱処理等を施し、良好な伸
線加工性を有するパーライト組織とすることを目的とし
て成分を規定している。DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the reasons for limiting the components will be described. In the present invention, the components are specified for the purpose of performing a patenting heat treatment or the like to obtain a pearlite structure having good drawing workability.
【0013】C:0.8〜1.5% C含有量が0.8%未満ではパテンティング材の強度、
伸線加工工程での加工硬化率が小さいので4000MP
a以上の引張強さを確保するためには極めて大きな伸線
加工歪が必要となる。そのため延性が劣化し、伸線工程
及び撚加工工程での断線が多発することになり、工業的
規模で生産することは極めて難しい。1.5%を超えて
Cを含有させた場合は、圧延線材あるいはパテンティン
グ処理材に初析セメンタイトが析出し、伸線加工性、撚
り加工性などが著しく劣化するために、C含有量を0.
8〜1.5%と規定した。C: 0.8 to 1.5% When the C content is less than 0.8%, the strength of the patenting material
4000MP due to small work hardening rate in wire drawing process
In order to secure a tensile strength of a or more, an extremely large drawing strain is required. For this reason, ductility is deteriorated, and disconnection occurs frequently in the wire drawing process and the twisting process, and it is extremely difficult to produce on an industrial scale. When C is contained in excess of 1.5%, proeutectoid cementite precipitates in the rolled wire or the patented material, and the wire drawing and twisting properties are significantly deteriorated. 0.
It was specified as 8 to 1.5%.
【0014】Si:0.10〜0.50% Siは脱酸元素、固溶体強化元素としての作用を利用す
るために添加される。特に、本発明ではAlを添加しな
いためSiは少なくとも0.10%以上は添加する必要
がある。しかし、0.50%を超えて添加するパーライ
ト組織中のフェライトの延性が劣化し、伸線加工性、撚
り加工性などが劣化するので、Si含有量を0.10〜
0.50%と規定した。Si: 0.10 to 0.50% Si is added in order to utilize the action as a deoxidizing element and a solid solution strengthening element. Particularly, in the present invention, since Al is not added, it is necessary to add at least 0.10% or more of Si. However, since the ductility of the ferrite in the pearlite structure to be added in excess of 0.50% is deteriorated, the wire drawing workability, the twist workability, and the like are deteriorated.
It was defined as 0.50%.
【0015】Mn:0.20〜0.70% Mnは脱酸元素、鋼中のSをMnSとして固定する作用
を利用するために添加されるばかりでなく、鋼の焼入れ
性を向上させ、強度を高めるために有効な元素である。
0.20%未満ではその効果が不足となる。一方、0.
70%を超えると偏析起因のミクロマルテンの発生によ
り伸線加工性、撚り加工性が著しく劣化するので、Mn
添加量を0.10〜0.70%と規定した。Mn: 0.20 to 0.70% Mn is added not only to utilize the deoxidizing element and the effect of fixing S in the steel as MnS, but also to improve the hardenability of the steel and improve the strength. Is an effective element to increase the
If it is less than 0.20%, the effect will be insufficient. On the other hand, 0.
If it exceeds 70%, drawability and twistability are significantly deteriorated due to generation of micro-marten due to segregation.
The amount added was defined as 0.10 to 0.70%.
【0016】Al:0.005%以下 本来Alは脱酸元素として添加されるが、脱酸生成物で
あるAl2O3は極細鋼線の伸線加工性、撚り加工性を著
しく劣化させるため、本発明においてはSi,Mnによ
る脱酸を行い、Alの添加量を極力抑える必要があるた
め、Alを0.005%以下に規定した。Alは含有し
ていなくてもよい。Al: 0.005% or less Al is originally added as a deoxidizing element, but Al 2 O 3 , which is a deoxidizing product, significantly deteriorates the drawability and twistability of ultrafine steel wire. In the present invention, since it is necessary to deoxidize with Si and Mn to minimize the amount of Al added, Al is specified to be 0.005% or less. Al does not have to be contained.
【0017】P:0.02%以下 Pは極細鋼線の靭性及び延性を低下させる元素であり、
偏析し易い元素である。従って本発明に於いては、P含
有量を0.02%以下にする必要がある。好ましくは
0.01%以下とする。P: 0.02% or less P is an element that lowers the toughness and ductility of the ultrafine steel wire.
It is an element that easily segregates. Therefore, in the present invention, the P content needs to be 0.02% or less. Preferably, it is 0.01% or less.
【0018】S:0.02%以下 SはP同様に極細鋼線の靭性及び延性を低下させる元素
であり、偏析し易い元素である。従って本発明に於いて
は、S含有量を0.02%以下にする必要がある。好ま
しくは0.01%以下とする。S: 0.02% or less S, like P, is an element that lowers the toughness and ductility of the ultrafine steel wire, and is an element that tends to segregate. Therefore, in the present invention, the S content needs to be 0.02% or less. Preferably, it is 0.01% or less.
【0019】O:0.005%以下 Oが0.005%を超えるとSiO2などの硬質な酸化
物系非金属介在物が多くなり、極細鋼線の伸線加工性、
撚り加工性を著しく劣化させるので0.005%以下に
規定する必要がある。O: 0.005% or less When O exceeds 0.005%, hard oxide-based nonmetallic inclusions such as SiO 2 increase, and the drawability of ultrafine steel wire increases.
It is necessary to set the content to 0.005% or less, since the twistability is significantly deteriorated.
【0020】N:0.005%以下 Nは0.005%を超えると歪時効により極細鋼線の靭
性及び延性に悪影響を及ぼすので0.005%以下に規
定する必要がある。N: 0.005% or less If N exceeds 0.005%, the strain aging adversely affects the toughness and ductility of the ultrafine steel wire, so it must be specified to 0.005% or less.
【0021】 5≦(Ca+Mg+REM)≦50ppm Al,Oの含有量を規定し、硬質な非金属介在物の量を
極力少なくする事に加えて、Ca,Mg,REMを添加
することによりこれらの酸化物とAl2O3,SiO2な
どが複合化し、軟質化することが極細鋼線の伸線加工
性、撚り加工性を向上させる上で有効である。非金属介
在物の複合化を十分達成するためには、鋼中に(Ca+
Mg+REM)で5ppm以上含有していることが必要
である。しかし、50ppmを超えて含有しても、その
効果が飽和することに加えて経済的ではないので5pp
m≦(Ca+Mg+REM)≦50ppmに規定した。5 ≦ (Ca + Mg + REM) ≦ 50 ppm The content of Al and O is specified, and in addition to minimizing the amount of hard nonmetallic inclusions, the addition of Ca, Mg, and REM oxidizes these oxides. It is effective to combine the material with Al 2 O 3 , SiO 2, etc. and soften it to improve the drawability and twistability of the ultrafine steel wire. In order to sufficiently achieve composite of nonmetallic inclusions, (Ca +
Mg + REM (Mg + REM). However, if the content exceeds 50 ppm, the effect is saturated and it is not economical.
m ≦ (Ca + Mg + REM) ≦ 50 ppm.
【0022】次に、キンク強度、引掛強度を規定した理
由について述べる。Next, the reason for defining the kink strength and the hook strength will be described.
【0023】捻回により生じる剪断歪は表面で最大であ
り、内部に進むに従い減少し、軸線上では零になるた
め、捻回試験は極細鋼線表層の変形能評価試験に相当
し、表層の変形能が著しく低い場合、早期に限界に到達
し、デラミネーションが発生することになる。従来の引
張強さの領域ではデラミネーションが発生しない程度、
つまり比較的小さな剪断歪に表層変形能が対応出来れば
撚り加工中の断線発生は抑制出来た。しかし、4000
MPa級以上極細鋼線からバンチャー式撚り加工機でコ
ードを製造する際、極細鋼線の剛性が高いのでコードが
ばらけないようにするために従来より大きなオーバーツ
イスト量が必要になり、極細鋼線表層にはより大きな剪
断歪が局部的に負荷されることになる。捻回試験はチャ
ック間で極細鋼線の表層に均一に剪断歪が分布する上
に、前述したようにデラミネーション発生の有無による
判定では小さな剪断歪に対する表層変形能しか評価出来
ない。そのためデラミネーションが発生しないことが4
000MPa級以上の引張強さを有する極細鋼線の良好
な撚り加工性を確保する上での必要十分条件となり得な
いので別の評価指標を確立し、その要求レベルを明確に
する必要があった。Since the shear strain caused by twisting is maximum on the surface, decreases as it goes inward, and becomes zero on the axis, the twisting test corresponds to a test for evaluating the deformability of the surface layer of a fine steel wire. If the deformability is extremely low, the limit will be reached early and delamination will occur. To the extent that delamination does not occur in the area of conventional tensile strength,
In other words, if the surface deformability could cope with relatively small shear strain, the occurrence of disconnection during twisting could be suppressed. But 4000
When manufacturing a cord from a super-fine steel wire with a buncher type twisting machine or higher, the rigidity of the ultra-fine steel wire is so high that a larger amount of overtwisting is required to prevent the cord from coming apart. A larger shear strain is locally applied to the wire surface layer. In the torsion test, the shear strain is uniformly distributed on the surface layer of the ultrafine steel wire between the chucks, and as described above, the judgment based on the presence or absence of delamination can evaluate only the surface deformability for a small shear strain. Therefore, delamination does not occur.
Since it was not possible to satisfy the necessary and sufficient conditions for ensuring good twisting workability of ultrafine steel wire having a tensile strength of 000 MPa class or more, it was necessary to establish another evaluation index and clarify the required level .
【0024】そこで本発明者らが高強度極細鋼線の撚り
加工性を確保するための要求特性を研究調査した結果、
極細鋼線表層に局部的に負荷される剪断歪の状況をシミ
ュレートする試験方法としてはキンク試験と引掛試験が
有効であることを見出した。キンク試験は1本の極細鋼
線でループを作り両端を引張り、その破断強度を評価す
る試験であり、ループ部の表層に剪断歪が局部的に負荷
される。また、引掛試験は2本の極細鋼線を互いに交差
させ、両端を引張りその破断強度を評価する試験であ
り、交差した部位の表層に局部的に剪断歪が負荷される
ので撚り工程での状況をより正確に再現出来る上にキン
ク試験、引掛試験での破断荷重により極細鋼線の撚り加
工性を定量的に評価することが可能となる。The inventors of the present invention have researched and investigated the required characteristics for ensuring the twistability of a high-strength ultrafine steel wire.
The kink test and the hook test were found to be effective as test methods for simulating the state of shear strain locally applied to the surface layer of ultrafine steel wire. The kink test is a test in which a loop is formed with a single ultrafine steel wire and both ends are pulled, and the breaking strength is evaluated. Shear strain is locally applied to the surface layer of the loop portion. In addition, the hooking test is a test in which two ultrafine steel wires are crossed with each other and both ends are pulled to evaluate the breaking strength. Since the shear strain is locally applied to the surface layer at the crossed portion, the situation in the twisting process is changed. Can be reproduced more accurately, and the twisting workability of the ultrafine steel wire can be quantitatively evaluated by the breaking load in the kink test and the hook test.
【0025】尚、キンク強度とはキンク試験での破断荷
重を引張破断荷重で割った値を%表示したものである。
また、引掛強度とは引掛試験での破断荷重を引張破断荷
重で割った値を%表示したものである。The kink strength is a value obtained by dividing a breaking load in a kink test by a tensile breaking load in%.
The hooking strength is a value obtained by dividing the breaking load in the hooking test by the tensile breaking load and expressed as a percentage.
【0026】特に、20%以上のキンク強度、80%以
上の引掛強度に規定することにより良好な撚り加工性が
確保できる。図1に0.20mm 4300MPa級極
細鋼線を撚り加工した場合の断線回数とキンク強度、引
掛強度、デラミネーションの関係を示した。デラミネー
ションが発生すれば断線回数は高い。しかし、デラミネ
ーションが発生しない場合でもキンク強度、引掛強度が
低い場合、やはり断線回数は高い。つまり本発明の範囲
内にキンク強度、引掛強度を制御することにより初めて
断線回数を低減出来る。In particular, by setting the kink strength to 20% or more and the hooking strength to 80% or more, good twist workability can be ensured. FIG. 1 shows the relationship among the number of disconnections, kink strength, hook strength, and delamination when a 0.20 mm 4300 MPa class ultrafine steel wire was twisted. If delamination occurs, the number of disconnections is high. However, even when delamination does not occur, if the kink strength and hooking strength are low, the number of disconnections is still high. That is, the number of disconnections can be reduced for the first time by controlling the kink strength and the hook strength within the range of the present invention.
【0027】また、最近、スチールコードの耐腐食疲労
寿命を向上させる目的でコードへのゴム浸透性の高いオ
ープン構造が採用されてきているが、コードのオープン
構造を保持するために撚り工程で曲げ歪を負荷して製造
される例がある。この場合も前述同様、極細鋼線表層に
局部的に大きな剪断歪が負荷されることになるが、キン
ク試験、引掛試験より正確に曲げ歪に対する極細鋼線表
層の変形能を評価する方法としては屈曲試験による屈曲
値の評価が有効である。Recently, an open structure having a high rubber permeability to the cord has been adopted for the purpose of improving the corrosion fatigue life of the steel cord, but in order to maintain the open structure of the cord, a bending process is performed in a twisting process. There is an example in which it is manufactured by applying strain. In this case, as described above, a large shear strain is locally applied to the surface of the ultrafine steel wire.However, as a method for evaluating the deformability of the surface of the ultrafine steel wire with respect to bending strain more accurately than the kink test and the hook test, Evaluation of the bending value by a bending test is effective.
【0028】ここで、屈曲値とは極細鋼線の一端を極細
鋼線の直径の5倍の半径の円弧を有した1対のつかみ具
に固定し、更に極細鋼線の他端に引張破断荷重の1%の
荷重を負荷し、円弧に沿って90度づつ順逆方向に交互
に繰り返し曲げた時の破断までの繰り返し回数のことで
ある。Here, the bending value means that one end of the ultrafine steel wire is fixed to a pair of gripping tools having an arc having a radius of five times the diameter of the ultrafine steel wire, and further, the other end of the ultrafine steel wire is tensilely broken. This is the number of repetitions up to fracture when a load of 1% of the load is applied and alternately repeated in the forward and reverse directions by 90 degrees along an arc.
【0029】特に、断線回数を低減するためには、キン
ク強度、引掛強度を本発明の範囲内に規定することに加
えて、屈曲値を80回以上に規定することが有効であ
る。図2にはデラミネーションが発生しない0.30m
m 4200MPa級極細鋼線を1×4のオープン構造
で撚り加工した場合の断線回数と屈曲値の関係を示し
た。キンク強度、引掛強度を本発明の範囲内に制御する
ことに加えて、屈曲値を80回以上にすることにより
0.30mm 4200MPa級のオープン構造コード
の撚り線断線回数が低減することが分かる。つまりデラ
ミネーションが発生しなくともキンク強度、引掛強度、
屈曲値が本発明の範囲になければ、断線回数は極めて高
い。In particular, in order to reduce the number of disconnections, it is effective to define the kink strength and the hooking strength within the range of the present invention and to define the bending value at 80 times or more. FIG. 2 shows 0.30 m without delamination
The relationship between the number of disconnections and the bending value when a 4200 MPa class ultrafine steel wire was twisted with an open structure of 1 × 4 was shown. It can be seen that, in addition to controlling the kink strength and the hooking strength within the range of the present invention, by setting the bending value to 80 or more, the number of twisted wire breaks of the 0.30 mm 4200 MPa class open structure cord is reduced. In other words, even without delamination, kink strength, hooking strength,
If the bending value is not within the range of the present invention, the number of disconnections is extremely high.
【0030】以上のようなキンク強度、引掛強度、屈曲
値を確保するためには、前述の成分範囲とすることに加
えて、仕上げ伸線工程での均一変形を促進し、C断面の
中心より0.4×(極細鋼線の直径)の位置のビッカー
ス硬度(HVs)と中心のビッカース硬度(HVc)の
差(HVs−HVc)が30以下にすることが有効であ
る。図3、4、5には0.20mm 4200MPa級
のC断面の硬度差とキンク強度、引掛硬度、屈曲値の関
係を示した。C断面の表層と中心の硬度差を本発明の範
囲に制御すれば均一な集合組織が形成されるなどの効果
により本発明の範囲のキンク強度、引掛強度、屈曲値を
確保することが可能となる。In order to secure the above kink strength, hooking strength, and bending value, in addition to the above-described component ranges, uniform deformation in the finish drawing step is promoted, and It is effective that the difference (HVs-HVc) between the Vickers hardness (HVs) at the position of 0.4 × (diameter of the ultrafine steel wire) and the Vickers hardness (HVc) at the center is 30 or less. FIGS. 3, 4, and 5 show the relationship between the hardness difference of the C section of 0.20 mm 4200 MPa class and the kink strength, hook hardness, and bending value. If the hardness difference between the surface layer and the center of the C section is controlled within the range of the present invention, it is possible to secure the kink strength, the hooking strength, and the bending value within the range of the present invention due to effects such as formation of a uniform texture. Become.
【0031】本発明の範囲に極細鋼線C断面の硬度差を
確保するためには例えば仕上げ伸線工程での均一変形を
促進する方法がある。特に、湿式潤滑剤のエマルション
粒径を微細にするなどにより仕上げ伸線工程での鋼線/
ダイス間の摩擦係数<0.07としてダイス伸線の際に
鋼線表層に付与される剪断歪を低減することが有効であ
る。In order to secure a difference in hardness of the cross section of the ultrafine steel wire C within the scope of the present invention, for example, there is a method of promoting uniform deformation in the finish drawing step. In particular, by reducing the emulsion particle size of the wet lubricant, etc.
It is effective to reduce the shear strain applied to the surface of the steel wire when the die is drawn by setting the friction coefficient between the dies to <0.07.
【0032】また、本発明の範囲に極細鋼線C断面の硬
度差を確保する方法として、前述の仕上げ伸線方法に加
えて、伸線加工途中に極細鋼線に捻り矯直加工をするこ
とも有効である。As a method of securing the hardness difference of the cross section of the ultrafine steel wire C within the scope of the present invention, in addition to the above-described finish drawing method, straightening of the ultrafine steel wire is performed during the drawing process. Is also effective.
【0033】例えば、図6に示すような捻り矯直加工に
より捻り歪みを付与した後に伸線加工することによりバ
ウジンガー効果などにより極細鋼線の表層を軟化させる
ことが可能となり、HVs−HVcを低減する結果、仕
上げ伸線工程で均一変形を促進したのと同等の効果を得
ることが出来る。特に、捻り矯直加工を付与することに
より表層の軟化が進み、HVs−HVcを負の値とする
ことも可能となり、更に表層の延性を向上することが可
能となる。For example, it is possible to soften the surface layer of the ultrafine steel wire by the Bausinger effect or the like by applying a torsion strain by a twist straightening process as shown in FIG. 6 and then performing a wire drawing process, thereby reducing HVs-HVc. As a result, an effect equivalent to promoting uniform deformation in the finish drawing step can be obtained. In particular, the surface layer is softened by applying the straightening process, and HVs-HVc can be set to a negative value, and the ductility of the surface layer can be further improved.
【0034】以上の特性を有する極細鋼線は4000M
Pa以上の極めて高強度であっても良好な撚り加工性を
有しており、その数本から数十本を撚り合わせることに
よりタイヤ、ベルト、ホース等の補強材として活用でき
る。The ultrafine steel wire having the above characteristics is 4000M
It has good twistability even with extremely high strength of Pa or more, and can be used as a reinforcing material for tires, belts, hoses, etc. by twisting several to tens of them.
【0035】[0035]
【0036】[0036]
【表1】 [Table 1]
【0037】(実施例1)以下に実施例を示して本発明
の効果を更に詳しく説明する。表1に示した化学成分の
1.8〜1.4mmの線径の鋼線を鉛パテンティング処
理、ブラスめっき処理後に湿式伸線により0.20mm
に伸縮した。以上の工程で製造した極細鋼線を撚り加工
工程で1×12に撚り、その断線回数を評価した。その
結果を表1に示す。本発明材No.1〜8と比較材N
o.9〜13を比較すると成分、キンク強度、引掛強度
保持率を本発明の範囲内に制御することにより撚り工程
での断線が極めて低いことが分かる。また、本発明の範
囲内のキンク強度、引掛強度を確保するためには極細鋼
線のC断面の硬度差をHV30以下に制御することが重
要であることも分かる。No.10はC含有量が1.5
%を超えるためパテンティング材に初析セメンタイトが
発生しているため、0.20mmまで伸線ができない。
No.11はAl含有量が多すぎるため、硬質介在物起
因で撚り工程での断線が多発している。No.12は
(Ca+Mg+REM)の含有量が少なく非金属介在物
の軟質化が不十分であり、撚り工程での断線が多発して
いる。No.13は(Ca+Mg+REM)の含有量が
50ppmを超えている。撚り線工程の断線回数はN
o.1,2と差が無く、50ppmを超えて含有しても
意味が無いことが分かる。No.14はC断面の硬度差
が大きくデラミネーションは発生しないが、キンク強度
が低い。No.15もC断面の硬度差が更に大きく、デ
ラミネーションは発生しないがキンク強度、引掛強度の
いずれもが低いため撚り線工程の断線回数が高い。(Embodiment 1) The effects of the present invention will be described in more detail with reference to the following embodiments. A steel wire having a wire diameter of 1.8 to 1.4 mm of the chemical components shown in Table 1 was subjected to lead patenting treatment and brass plating treatment, and then 0.20 mm by wet drawing.
Stretched. The ultrafine steel wire produced in the above process was twisted to 1 × 12 in the twisting process, and the number of disconnections was evaluated. Table 1 shows the results. Inventive material No. 1-8 and comparative material N
o. Comparing Nos. 9 to 13, it can be seen that disconnection in the twisting step is extremely low by controlling the components, kink strength and hook strength retention within the range of the present invention. Further, it can be seen that it is important to control the hardness difference of the C section of the ultrafine steel wire to HV30 or less in order to secure the kink strength and the hooking strength within the range of the present invention. No. 10 has a C content of 1.5
%, Proeutectoid cementite is generated in the patenting material, so that wire drawing cannot be performed to 0.20 mm.
No. In No. 11, the Al content is too large, and the disconnection in the twisting process frequently occurs due to hard inclusions. No. In No. 12, the content of (Ca + Mg + REM) is small, the softening of the nonmetallic inclusions is insufficient, and the disconnection frequently occurs in the twisting step. No. 13 has a (Ca + Mg + REM) content exceeding 50 ppm. The number of disconnections in the stranding process is N
o. It can be seen that there is no difference from 1 and 2, and it is meaningless to contain more than 50 ppm. No. No. 14 has a large hardness difference in the C section and does not cause delamination, but has a low kink strength. No. In No. 15, the difference in hardness in the C section is even greater and delamination does not occur, but the kink strength and hooking strength are both low, so that the number of disconnections in the stranded wire process is high.
【0038】[0038]
【表2】 [Table 2]
【0039】(実施例2)更に捻り矯直加工を適用し、
C断面の硬度差を一層小さくすることによりキンク強
度、引掛強度を高めることに加えて、屈曲値を本発明の
範囲に制御することが可能になる。表2に示した化学成
分の2.5mmの線径の鋼線を鉛パテンティング処理、
ブラスめっき処理後に湿式伸線により0.35mmに伸
線した。伸線途中の0.60mmで捻れ矯直加工を付与
した。尚、捻り矯直加工の条件は極細鋼線に付与するバ
ックテンションをTSの2%とし、曲率が10mmの矯
直用ダイス5個、それぞれの間隔を30mmとして配列
した。ダイス押し込み量は5mmとし、400mmに一
回転の捻り歪みを付与した後に0.35mmまで伸線し
た。その後、撚り加工工程で1×4のオープン構造に撚
り、その断線回数を評価した。その結果を表2に示す。
キンク強度、引掛強度を高めることに加えて、屈曲値を
本発明の範囲に制御することによりオープン構造でも撚
り工程での断線回数を低減することが可能となる。N
o.19,20は捻り矯直加工を施していないため、デ
ラミネーションは発生しないが、C断面の硬度差が大き
く、キンク強度、引掛強度、屈曲値が低いため撚線工程
での断線回数が高い。(Embodiment 2) Further, twist straightening is applied,
By further reducing the hardness difference in the C section, the kink strength and the hook strength can be increased, and the bending value can be controlled within the range of the present invention. Lead patenting treatment of a steel wire having a wire diameter of 2.5 mm having the chemical composition shown in Table 2,
After the brass plating, it was drawn to 0.35 mm by wet drawing. A straightening process was applied at 0.60 mm during drawing. The conditions of the straightening process were as follows. The back tension applied to the ultrafine steel wire was 2% of TS, and five straightening dies having a curvature of 10 mm were arranged at intervals of 30 mm. The pressing amount of the dice was set to 5 mm, and after a single twist of 400 mm was applied, the wire was drawn to 0.35 mm. Then, in the twisting step, the wire was twisted into a 1 × 4 open structure, and the number of disconnections was evaluated. Table 2 shows the results.
In addition to increasing the kink strength and the hooking strength, by controlling the bending value within the range of the present invention, it is possible to reduce the number of disconnections in the twisting process even in an open structure. N
o. In Nos. 19 and 20, no delamination occurs because no twist correction processing is performed, but the hardness difference in the C section is large, and the kink strength, hooking strength and bending value are low, so that the number of disconnections in the twisting step is high.
【0040】[0040]
【発明の効果】以上に詳しく説明したように、極細鋼線
の成分を制御することに加えて、C断面の硬度差を小さ
くし、キンク強度、引掛強度、更に屈曲値を所定の値に
制御することにより従来にない高強度スチールコールド
が製造可能となる。As described in detail above, in addition to controlling the components of the ultrafine steel wire, the hardness difference in the C section is reduced, and the kink strength, hook strength, and bending value are controlled to predetermined values. By doing so, it is possible to manufacture a high-strength steel cold that has never been seen before.
【図1】0.20mm 4300MPa級極細鋼線を1
×12に撚り加工した場合の断線回数とキンク強度、引
掛強度、デラミネーションの関係を示したグラフであ
る。FIG. 1 shows a 0.20 mm 4300 MPa class ultrafine steel wire
4 is a graph showing the relationship among the number of disconnections, kink strength, hook strength, and delamination when twisting is performed to × 12.
【図2】デラミネーションが発生しない0.30mm
4300MPa級極細鋼線を1×4に撚り加工した場合
の断線回数と屈曲値の関係を示したグラフである。FIG. 2 0.30 mm without delamination
4 is a graph showing the relationship between the number of disconnections and the bending value when a 4300 MPa class ultrafine steel wire is twisted into 1 × 4.
【図3】C断面の硬度差とキンク強度の関係を示したグ
ラフである。FIG. 3 is a graph showing a relationship between a difference in hardness of a C section and a kink strength.
【図4】C断面の硬度差と引掛強度の関係を示したグラ
フである。FIG. 4 is a graph showing a relationship between a hardness difference and a hooking strength of a C section.
【図5】C断面の硬度差と屈曲値の関係を示したグラフ
である。FIG. 5 is a graph showing a relationship between a hardness difference and a bending value of a C section.
【図6】捻り矯直加工の概要を示した図である。FIG. 6 is a diagram showing an outline of a straightening process.
1 極細鋼線 2 矯直用ダイス 3 矯直用ダイスセットホルダー DESCRIPTION OF SYMBOLS 1 Ultrafine steel wire 2 Straightening die 3 Straightening die set holder
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.7 識別記号 FI C22C 38/06 C22C 38/06 D07B 1/06 D07B 1/06 A (56)参考文献 特開 平2−10220(JP,A) 特開 平4−371549(JP,A) 特開 平6−336649(JP,A) 特開 平8−120407(JP,A) (58)調査した分野(Int.Cl.7,DB名) C22C 38/00 301 B21C 1/00 B21C 9/00 B21C 19/00 B60C 9/00 C22C 38/06 D07B 1/06 ────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. 7 Identification code FI C22C 38/06 C22C 38/06 D07B 1/06 D07B 1/06 A (56) References JP-A-2-10220 (JP, A JP-A-4-371549 (JP, A) JP-A-6-336649 (JP, A) JP-A-8-120407 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) C22C 38/00 301 B21C 1/00 B21C 9/00 B21C 19/00 B60C 9/00 C22C 38/06 D07B 1/06
Claims (5)
の直径、4000MPa以上の引張強さ、20%以上の
キンク強度、80%以上の引掛強度を有し、かつC断面
の中心より0.4×(極細鋼線の直径)の位置のビッカ
ース硬度(HVs)と中心のビッカース硬度(HVc)
の差(HVs−HVc)が30以下であることを特徴と
する高強度高延性極細鋼線。1. Weight%: C: 0.8-1.50%, Si: 0.10-0.50%, Mn: 0.20-0.70%, Al: 0.005% or less, P: 0.02% or less, S: 0.02% or less, O: 0.005% or less, N: 0.005% or less, 5 ≦ (Ca + Mg + REM) ≦ 50ppm, with the balance being iron and unavoidable impurities It has a diameter of 0.40 mm or less, a tensile strength of 4000 MPa or more, a kink strength of 20% or more, a hooking strength of 80% or more, and 0.4 × (diameter of extra fine steel wire) from the center of the C section. Vickers hardness (HVs) at center and Vickers hardness (HVc) at center
(HVs-HVc) is 30 or less.
曲値が80回以上を有することを特徴とする高強度高延
性極細鋼線。尚、屈曲値とは極細鋼線の一端を極細鋼線
の直径の5倍の半径の円弧を有した1対のつかみ具に固
定し、更に極細鋼線の他端に引張破断荷重の1%の荷重
を負荷し、円弧に沿って90度づつ順逆方向に交互に繰
り返し曲げたときの破断までの繰り返し回数のことであ
る。2. The high-strength and high-ductility ultra-fine steel wire according to claim 1, wherein the bending value has at least 80 turns. The bending value means that one end of the ultrafine steel wire is fixed to a pair of grips having an arc having a radius five times the diameter of the ultrafine steel wire, and the other end of the ultrafine steel wire is 1% of the tensile breaking load. This is the number of repetitions up to the fracture when bending is repeated alternately in the forward and reverse directions by 90 degrees along the arc while applying the load of.
加工したものであることを特徴とする撚り線。3. A stranded wire obtained by twisting the ultrafine steel wire according to claim 1 or 2.
摩擦係数を0.07以下とすることを特徴とする請求項
1又は2に記載の高強度高延性極細鋼線の製造方法。4. The method for producing a high-strength, high-ductility ultrafine steel wire according to claim 1, wherein the coefficient of friction between the steel wire and the die in the finishing wire drawing step is 0.07 or less. .
摩擦係数を0.07以下とし、伸線加工途中に極細鋼線
に捻り矯直加工をすることを特徴とする請求項1又は2
に記載の高強度高延性極細鋼線の製造方法。5. The method according to claim 1, wherein a coefficient of friction between the steel wire and the die in the finishing wire drawing step is set to 0.07 or less, and the ultra-fine steel wire is subjected to a straightening process during the wire drawing process. Or 2
3. The method for producing a high-strength and high-ductility ultrafine steel wire according to item 1.
Priority Applications (1)
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JP11057106A JP3001572B1 (en) | 1999-03-04 | 1999-03-04 | High-strength, high-ductility ultrafine steel wire, stranded wire, and method for producing the same |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
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JP11057106A JP3001572B1 (en) | 1999-03-04 | 1999-03-04 | High-strength, high-ductility ultrafine steel wire, stranded wire, and method for producing the same |
Publications (2)
Publication Number | Publication Date |
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JP3001572B1 true JP3001572B1 (en) | 2000-01-24 |
JP2000256792A JP2000256792A (en) | 2000-09-19 |
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Also Published As
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