JP4797305B2 - Invar alloy wire with excellent strength and twisting characteristics and manufacturing method thereof - Google Patents
Invar alloy wire with excellent strength and twisting characteristics and manufacturing method thereof Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
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Description
【０００１】
【発明の属する技術分野】
この発明は、強度と捻回特性とが必要とされ且つ低熱膨張が要求される送電線等に用いられるインバー合金線及びその製造方法に関する。
【０００２】
【従来の技術及び発明が解決しようとする課題】
従来より、送電線には鋼芯アルミニウム撚線（ACSR線）が用いられているが、近年送電容量向上，鉄塔設置コスト削減のため高強度の低弛度送電線が用いられるようになって来ている。
送電線を高強度とすると鉄塔と鉄塔との間隔を大きくとることが可能となり、また鉄塔の高さも低くすることが可能となって、鉄塔設置コストを低減することができる。
現状実用化されている芯材の強度は引張強さが１１５０〜１２５０ＭＰａ程度であるが、コスト低減のためにより強度の高い材料が求められている。
【０００３】
１つの手段として、Coを添加し、加工誘起マルテンサイト変態を利用する方法が提案されているが、Coはコストの面から極力低減することが望ましい。
本発明は基本的にCoを使用せず、必要な低熱膨張特性，捻回特性等を維持したまま１３００ＭＰａを超える高強度が得られるインバー合金線及びその製造方法を提供することを目的とする。
【０００４】
【課題を解決するための手段】
本発明は以上の事情の下に案出されたもので、請求項１はインバー合金線に関し、重量％で、C：０．２０〜０．４０％，Si：≦０．８％，Mn：≦１．０％，P：≦０．０５０％，S：≦０．０１５％，Cu：≦１．０％，Ni：３５〜４０％，Cr：≦０．５％，Mo：１．５〜６．０％，V：０．０５〜１．０％，O：≦０．０１５％，N：≦０．０３％であって、Mo／V≧１．０且つ（０．３Mo＋V）≧４Cであり、残部Fe及び不可避的不純物から成る組成を有し、２０〜２３０℃までと２３０〜２９０℃までの平均線熱膨張係数が、それぞれ３．７×１０−６以下，１０．８×１０−６以下であることを特徴とする。
【０００５】
請求項２のものは、請求項１において、更にW，Co，Ti，Nb，Ta，Hfの１種又は２種以上を重量％で以下の範囲、W：≦３％，Co：≦３％，Ti：≦０．５％，Nb：≦０．５％，Ta：≦０．５％，Hf：≦０．５％で含有していることを特徴とする。
【０００６】
請求項３のものは、請求項１，２の何れかにおいて、更にCa，Mg，B，REM（REMは元素周期律表にて３Ａ族として分類される金属元素の１種又は２種以上）から選ばれる１種又は２種以上を合計で０．０００５〜０．０１００重量％含有していることを特徴とする。
【０００７】
請求項４はインバー合金線の製造方法に関し、請求項１〜３の何れかの組成のインバー合金を線材圧延後２０〜７５％の範囲で冷間加工し、その後６２５〜７５０℃の温度範囲で熱処理し、しかる後６０％以上の冷間加工を施し、その状態で引張強さが１３００ＭＰａを超えることを特徴とする。
【０００８】
【作用】
本発明は、インバー合金における化学成分について鋭意検討を重ねた結果、C，Mo，Vを有効に利用し且つ特定の成分範囲に限定することにより、優れた捻回特性に加え、高強度，低熱膨張特性を確保し得たものである。
【０００９】
本発明では、Cを０．２０〜０．４０％に規定するとともにMo／V≧１．０，（０．３Mo＋V）≧４Cとすることが必須であるが、これは以下のような意味を有している。
【００１０】
本発明では、インバー合金中にCとVとを添加することで合金中にVの炭化物を析出させ、その析出硬化によって合金の強度を高める。但しVのみの添加の場合、十分にインバー合金線を高強度化することができない。
VとともにMoをMo／V≧１．０となる比率で添加し、そしてそれらの炭化物を析出させることで目的とする高強度を得ることができる。
【００１１】
その理由は以下の点にあるものと考えられる。
Moを添加しないで単にVのみを添加した場合（炭化物形成元素として）、Vの炭化物が析出するが、この析出物は粗大な粒子となり易く、十分な高強度化を果すことができない。
これに対してMoをVと併せて添加すると、MoがMo２C又はMCないしM８C７型の微細な炭化物を析出して、炭化物の粗大粒子化を抑止する。この結果インバー合金線の強度が効果的に高強度化される。
【００１２】
但しこれらMoとVとの炭化物析出による高強度化を十分に達成するためには、それらの添加比率をMo／V≧１．０としなければならない。
この式を満足しないと粗大な炭化物が析出してしまい、強化が効率的に行われなくなる。
【００１３】
以上のようにインバー合金線を十分に高強度化するためにはMo／V≧１．０とすることが必要であるが、単にこの式を満足しただけでは十分且つ安定した捻回特性が得られない。
インバー合金線における高強度を維持しながら安定した捻回特性を実現するためには、（０．３Mo＋V）≧４Cとしなければならない。
ここで捻回特性は破断に到るまで何回捻ることができるかといった特性である。
【００１４】
上記の式（０．３Mo＋V）≧４Cは、フリーカーボン（遊離カーボン）となるべきCをMoとVとによって完全固定化し、フリーカーボンが生成しない量でMoとVとを添加することを意味している。
【００１５】
インバー合金線における捻回特性は主として変形能の問題であり、強度が弱く変形能が大であればインバー合金線を捻ったときに十分に捻ることができる。
しかしインバー合金線の強度が高強度化すると、詳しくは単に高強度化しただけであると、変形能の低下に基づいてインバー合金線を捻ったときに捻切れ易くなってしまう。
【００１６】
而してインバー合金中にフリーカーボンがあり且つその量が多くなると、インバー合金線を捻ったときに変形が局部に集中し、そこから簡単に捻切れてしまうといった現象を生じる。
これに対してインバー合金中のフリーカーボンをMoとVとで固定しておくとこれを良好に防止することができる。
【００１７】
その理由もまた明らかでないが、推察として加工硬化能がこの問題に大きく関与しているものと考えられる。
詳しくは、インバー合金中のCをMoとVとで固定しておくことで加工硬化能が高まり、この場合インバー合金線を捻って行くと変形部分が硬化を起して同部分の変形に対する抵抗力が大となり、この結果変形部位と加工硬化とが次々と移行して行き、その結果として破断に到るまでの捻り回数、即ち捻回特性が高くなるものと考えられる。
【００１８】
即ち本発明においてMo／V≧１．０，（０．３Mo＋V）≧４Cの何れをも満足することで、高強度且つ安定した捻回特性が得られる。
【００１９】
本発明においては、必要に応じてW，Co，Ti，Nb，Ta，Hfの１種又は２種以上を上記所定量以下の範囲で含有させることができ（請求項２）、更にまたCa，Mg，B，REMの１種又は２種以上を必要に応じて含有させることができる（請求項３）。
【００２０】
次に上記請求項１〜３における合金の化学成分の限定理由を以下に詳述する。
C：０．２０〜０．４０％
Cは微細な炭化物を形成し析出硬化により強度を高めることから必須な元素であり、１３００ＭＰａの引張強さを得るには０．２０％は最低限必要である。
但し過剰な添加は捻回特性，低熱膨張特性に悪影響を及ぼすことから０．４０％を上限とする。
【００２１】
Si：≦０．８％
Siは鋼の脱酸剤としては有効であるものの捻回特性，低熱膨張特性の面からは低いほど望ましく、上限を０．８％とする。望ましくは０．５％以下である。
【００２２】
Mn：≦１．０％
Mnは鋼の脱酸剤として作用する。また不純物元素であるSをMnSの形で固定し、良好な熱間加工性を確保するのに有効である。
但し捻回特性，低熱膨張特性の面からは低いほど望ましく、上限を１．０％とする。
【００２３】
P：≦０．０５０％
Pは粒界に偏析し、粒界腐食感受性を高める外、靭性の低下を招くため低い方が望ましいが、必要以上の低減はコストの上昇を招くため上限を０．０５０％とする。望ましくは０．０２０％以下である。
【００２４】
S：≦０．０１５％
Sは被削性を向上させるのに有効な化合物の構成元素であるものの、熱間加工性を極端に低下させることから低減することが望ましく、上限を０．０１５％とする。
【００２５】
Cu：≦１．０％
Cuは強度の向上に有効であるが過剰な添加は熱間加工性を劣化させ、熱膨張が増加することから、１．０％を上限とする。
【００２６】
Ni：３５〜４０％
Niは低熱膨張特性を確保するのに必須である。その範囲は３５〜４０％が良好である。特に低熱膨張特性が重視される場合には３７〜３９％の範囲とするのが望ましい。
【００２７】
Cr：≦０．５％
Crは捻回特性を向上させるのに有効ではあるが、熱膨張係数を大きくすることから上限を０．５％に規定する。
【００２８】
Mo：１．５〜６．０％
Moは微細なMo２C又はMC，M８C７型の炭化物として析出し、これにより強度と捻回特性とを向上させる。これらの特性を確保するため１．５％を下限とする。
一方６．０％を超えると熱膨張特性が高くなることがあるためこれを上限とする。
【００２９】
V：０．０５〜１．０％
VはMoと同様、MC，M８C７型の炭化物として析出し、強度と捻回特性とを向上させる。その下限は０．０５％である。
一方１．０％を超えて添加すると粗大な炭化物が生成し、捻回特性，靭延性を劣化させることからこれを上限とする。
【００３０】
O：≦０．０１５％
Oは酸化物を形成し、捻回特性，靭延性を低下させることから極力低減した方が良いため、上限を０．０１５％とする。望ましくは０．００８％以下、更に望ましくは０．００３％以下である。
【００３１】
N：≦０．０３％
Nは窒化物を形成し、捻回特性，靭延性を低下させることから極力低減した方が良いため、上限を０．０３％とする。望ましくは０．０１２％以下、更に望ましくは０．００８％以下である。
【００３２】
Mo／V≧１．０
MoとVとのバランスをとることにより更に高強度が得られる。
この式を満足すると、最初にVとMoとの成分バランスがとれたMC又はM８C７型の炭化物が生成し、そしてこの式の値が大きくなるにつれMo２Cが形成され、これらが強度と捻回特性との両方に有効な形態の析出物となる。
但し１．０未満だと高い強度を得ることができ難くなる。望ましくは１．５以上、更に望ましくは２．５以上とする。
【００３３】
（０．３Mo＋V）≧４C
安定した捻回特性を確保するためこの式を満足させる必要がある。
MoやVの炭化物を形成しないCが過剰にあり過ぎると、高い強度は得られるものの安定した捻回特性を得ることが極めて困難となる。
【００３４】
W：≦３％
Wはより高強度を得るのに有効である。但し過剰な添加は熱間加工性の低下を招くため３％以下とする。
【００３５】
Co：≦３％
基本的にはCoはコストの上昇を招くことから無添加とするが、より高い強度を望まれる場合添加しても良い。
但しコストの上昇を鑑み３％を上限とする。
【００３６】
Ti，Nb，Ta，Hf：≦０．５％
Ti，Nb，Ta，HfはMo，Vと同様炭化物を形成し、強度や捻回特性を向上させることに有効であるが、特性の向上に有効でない粗大な炭化物を形成し易いことからそれぞれ０．５％以下とする。
【００３７】
Ca，Mg，B，REM：０．０００５〜０．０１００％
Ca，Mg，B，REMは鋼の熱間加工性を向上させるのに有効な元素であることから０．０００５％を下限として添加しても良い。
しかし過剰に添加しても効果が飽和し、逆に熱間加工性を低下させることからその上限を０．０１００％とする。
尚REMはCe，La或いはそれらの合金から成るものである。
【００３８】
次に請求項４はインバー合金線の製造方法に関するもので、この製造方法では、インバー合金を線材圧延した後加工率２０〜７５％の範囲で冷間加工を行う。
この冷間加工は、次の熱処理の段階で強度と捻回特性に効果のある微細で均一な炭化物を形成するための予備歪みを付与するために行われる。
【００３９】
この冷間加工において、加工率２０％未満では十分な予備歪みを与えることができず、逆に７５％を超えると歪み量が大きくなり過ぎ、次工程の熱処理の際に母相の再結晶度が大きくなり、十分な強度が得られ難くなる。
【００４０】
これに続く６２５〜７５０℃の温度範囲での熱処理は、MoとVとの微細な炭化物を均一に母相中に分散析出させ、その析出強化により合金強度の上昇を図るとともに、母相の転位密度を低下させ、適切な捻回特性を確保するためのものである。
ここで熱処理温度が６２５℃未満では、母相中の転位密度の低下や炭化物の析出量が十分ではなく、逆に７５０℃を超えると母相の再結晶度が大きくなり過ぎ、十分な強度が得られ難くなる。
【００４１】
これに続く冷間加工は必要な強度を確保するために行うものであり、その際最低でも６０％の加工率が必要である。
これにより引張強さ１３００ＭＰａを超える強度を有するインバー合金線が得られる。
尚、線材圧延後１１００℃程度の温度で溶体化処理を施しても良く、また途中工程に適宜表面の傷をなくすための皮剥ぎを行っても良い。
【００４２】
【実施例】
次に本発明の実施例を以下に詳述する。
＜実施例１＞
表１に示す化学成分を有する鋼を高周波誘導炉にて真空誘導溶解し、鋼塊１５０ｋｇを得た。そしてこれを１１５０℃に加熱し、熱間鍛造により直径６５ｍｍの丸棒に加工した。
それらを１１００℃加熱後線材圧延し、直径１３ｍｍのコイルを作製した。そしてこれらの素材を表１に示す条件で加工した。
【００４３】
詳しくは、表１に示す加工率で冷間伸線加工し（伸線１）、次いで同表に示す温度条件で熱処理を行った。尚熱処理は６時間加熱しその後空冷の条件で行った。
続いて皮削り（皮剥ぎ）を行い、しかる後同表に示す加工率で冷間伸線加工を行い（伸線２）、引張強さ，捻回特性（捻回値），熱膨張係数等の特性評価を行った。結果が表１に併せて示してある。
【００４４】
【表１】
＜実施例２＞
表２に示す化学成分を有する鋼を電気炉にて溶解し、次いでＡＯＤ精錬を行って鋼塊２．５ｔを得た。これを分塊圧延した後、１１８０℃で十分に加熱し、熱間圧延により直径１３ｍｍの丸棒に加工した。
そしてこれらの素材を表２に示す条件で加工した。
【００４６】
詳しくは、表２に示す加工率で冷間伸線加工し（伸線１）、次いで同表に示す温度条件で熱処理を行った。尚熱処理は６時間加熱しその後空冷の条件で行った。
続いて皮削り（皮剥ぎ）を行い、しかる後同表に示す加工率で冷間伸線加工した（伸線２）。
そしてそれらについて引張試験，捻回試験，低熱膨張係数測定を行い、各特性評価を行った。結果が表２に併せて示してある。
【００４７】
【表２】
これら実施例の結果にみられるように、本発明例のものは良好な引張強さ（１３００ＭＰａ以上），捻回特性及び低熱膨張特性が得られている。
これに対して、C，Mo，V，Mo／V，（０．３Mo＋V）の値が本発明の条件を満たしていない比較例のものは、引張強さ，捻回特性の何れか一方又は両方が低く、特性的に満足の行くものが得られていない。
【００４９】
尚表２において、比較例２０，２１はSiの含有量が本発明の範囲を超えて多いものである。
このようにSiの含有量が本発明の範囲を超えて多く含有されていると、捻回特性が低くなってしまう。
【００５０】
表１において、比較例１２〜１６は、化学組成的には請求項１の条件を満たしているものの、製造条件が請求項４に規定する条件を満たしていないものの例である。
これら比較例の場合必ずしも良好な特性が得られていない。
【００５１】
このことから、本発明においては合金の化学成分を請求項１に規定する範囲内に規制することが一義的に重要であり、このことによって良好な強度及び捻回特性，低熱膨張特性を得ることが可能となるが、その際にインバー合金線の製造方法も重要であり、合金成分を請求項１に規定する範囲となすことと、製造条件を請求項４に規定する条件となすことと相俟って、最も望ましい結果が得られることを表している。
【００５２】
以上本発明の実施例を詳述したがこれはあくまで一例示であり、本発明はその主旨を逸脱しない範囲において種々変更を加えた態様で実施可能である。
【００５３】
【発明の効果】
以上のように本発明のインバー合金線によれば、強度及び捻回特性，低熱膨張特性の何れをも良好となし得、従ってこれを送電線に用いたとき、鉄塔の設置間隔を広く、また鉄塔の必要高さを低くすることができ、鉄塔設置のためのコストを低減することができるなど優れた効果を奏する。
また本発明の製造方法によれば、上記インバー合金の有する特性を最大限に引き出すことが可能となる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an invar alloy wire used for a power transmission line or the like that requires strength and twisting characteristics and requires low thermal expansion, and a manufacturing method thereof.
[0002]
[Prior art and problems to be solved by the invention]
Conventionally, steel core aluminum stranded wires (ACSR wires) have been used for transmission lines, but in recent years, high-strength, low-sag transmission lines have come to be used in order to improve transmission capacity and reduce tower installation costs. ing.
When the transmission line is made high in strength, it is possible to increase the distance between the steel tower and the steel tower, and it is also possible to reduce the height of the steel tower, thereby reducing the steel tower installation cost.
The core material currently in practical use has a tensile strength of about 1150 to 1250 MPa, but a material with higher strength is required for cost reduction.
[0003]
As one means, a method of adding Co and utilizing processing-induced martensitic transformation has been proposed, but it is desirable to reduce Co as much as possible from the viewpoint of cost.
An object of the present invention is to provide an invar alloy wire which can obtain high strength exceeding 1300 MPa while maintaining necessary low thermal expansion characteristics, twisting characteristics, etc. without using Co, and a method for producing the same.
[0004]
[Means for Solving the Problems]
The present invention has been devised under the above circumstances. Claim 1 relates to an Invar alloy wire, in terms of weight percent, C: 0.20 to 0.40%, Si: ≦ 0.8%, Mn: ≦ 1.0%, P: ≦ 0.050%, S: ≦ 0.015%, Cu: ≦ 1.0%, Ni: 35-40%, Cr: ≦ 0.5%, Mo: 1.5 ˜6.0%, V: 0.05 to 1.0%, O: ≦ 0.015%, N: ≦ 0.03%, and Mo / V ≧ 1.0 and (0.3Mo + V) ≧ 4C, the composition comprising the balance Fe and inevitable impurities, and the average linear thermal expansion coefficients from 20 to 230 ° C. and from 230 to 290 ° C. are not more than 3.7 × 10 −6 and 10.8 ×, respectively. 10 −6 or less.
[0005]
A second aspect of the present invention is the same as in the first aspect, further comprising one or more of W, Co, Ti, Nb, Ta, and Hf in the following ranges in terms of weight%, W: ≦ 3%, Co: ≦ 3% , Ti: ≦ 0.5%, Nb: ≦ 0.5%, Ta: ≦ 0.5%, Hf: ≦ 0.5%.
[0006]
Claim 3 is that according to any one of claims 1 and 2, further including Ca, Mg, B, REM (REM is one or more metal elements classified as group 3A in the periodic table of elements) It contains 0.0005 to 0.0100% by weight in total of one or more selected from the above.
[0007]
Claim 4 relates to a method for producing an Invar alloy wire, wherein the Invar alloy having the composition of any one of claims 1 to 3 is cold worked in a range of 20 to 75% after wire rod rolling, and thereafter in a temperature range of 625 to 750 ° C. It is characterized in that it is heat-treated and then subjected to cold working of 60% or more, and in that state the tensile strength exceeds 1300 MPa.
[0008]
[Action]
As a result of intensive investigations on chemical components in Invar alloys, the present invention effectively uses C, Mo, V and limits it to a specific component range, thereby providing high strength and low heat in addition to excellent twisting characteristics. The expansion characteristics can be secured.
[0009]
In the present invention, it is essential that C is defined as 0.20 to 0.40% and Mo / V ≧ 1.0 and (0.3Mo + V) ≧ 4C. This means the following meanings: Have.
[0010]
In the present invention, by adding C and V to the Invar alloy, V carbide is precipitated in the alloy, and the strength of the alloy is increased by precipitation hardening. However, when only V is added, the strength of the Invar alloy wire cannot be sufficiently increased.
The desired high strength can be obtained by adding Mo together with V at a ratio of Mo / V ≧ 1.0 and precipitating their carbides.
[0011]
The reason is considered to be as follows.
When only V is added without adding Mo (as a carbide-forming element), V carbide precipitates, but this precipitate tends to be coarse particles, and sufficient strength cannot be achieved.
On the other hand, when Mo is added together with V, Mo precipitates fine carbides of Mo 2 C or MC or M 8 C 7 type and suppresses coarsening of carbides. As a result, the strength of the Invar alloy wire is effectively increased.
[0012]
However, in order to sufficiently achieve high strength by precipitation of carbides of these Mo and V, their addition ratio must be Mo / V ≧ 1.0.
If this formula is not satisfied, coarse carbides are deposited, and strengthening cannot be performed efficiently.
[0013]
As described above, it is necessary to satisfy Mo / V ≧ 1.0 in order to sufficiently increase the strength of the Invar alloy wire, but sufficient and stable twisting characteristics can be obtained simply by satisfying this equation. I can't.
In order to realize a stable twisting characteristic while maintaining high strength in the Invar alloy wire, (0.3Mo + V) ≧ 4C must be satisfied.
Here, the twisting property is a property of how many times it can be twisted until it reaches rupture.
[0014]
The above formula (0.3Mo + V) ≧ 4C means that C to be free carbon (free carbon) is completely fixed by Mo and V, and Mo and V are added in such an amount that free carbon is not generated. ing.
[0015]
The twisting characteristic of the Invar alloy wire is mainly a problem of deformability. If the strength is weak and the deformability is large, the Invar alloy wire can be sufficiently twisted.
However, if the strength of the Invar alloy wire is increased, specifically, if the strength is simply increased, the Invar alloy wire is easily twisted when the Invar alloy wire is twisted based on a decrease in deformability.
[0016]
Thus, if there is free carbon in the Invar alloy and the amount thereof increases, a phenomenon occurs in which the deformation concentrates locally when the Invar alloy wire is twisted and is easily twisted therefrom.
On the other hand, if the free carbon in the Invar alloy is fixed with Mo and V, this can be prevented well.
[0017]
The reason for this is also not clear, but it is presumed that work hardening ability is greatly involved in this problem.
Specifically, work hardening ability is increased by fixing C in Invar alloy with Mo and V. In this case, when the Invar alloy wire is twisted, the deformed part hardens and resistance to deformation of the same part It is considered that the force increases, and as a result, the deformed portion and the work hardening shift one after another, and as a result, the number of twists until the breakage is reached, that is, the twist characteristics are increased.
[0018]
That is, in the present invention, satisfying both Mo / V ≧ 1.0 and (0.3Mo + V) ≧ 4C, high strength and stable twisting characteristics can be obtained.
[0019]
In the present invention, one or more of W, Co, Ti, Nb, Ta, and Hf can be contained in the range of the predetermined amount or less as necessary (Claim 2), and Ca, One, two or more of Mg, B, and REM can be contained as required (Claim 3).
[0020]
Next, the reasons for limiting the chemical components of the alloy in claims 1 to 3 will be described in detail below.
C: 0.20 to 0.40%
C is an essential element because it forms fine carbides and increases the strength by precipitation hardening, and 0.20% is the minimum necessary to obtain a tensile strength of 1300 MPa.
However, excessive addition adversely affects the twisting characteristics and low thermal expansion characteristics, so 0.40% is made the upper limit.
[0021]
Si: ≦ 0.8%
Although Si is effective as a deoxidizer for steel, it is desirable that it is lower in terms of twisting characteristics and low thermal expansion characteristics, and the upper limit is set to 0.8%. Desirably, it is 0.5% or less.
[0022]
Mn: ≦ 1.0%
Mn acts as a deoxidizer for steel. It is also effective for securing good hot workability by fixing S, which is an impurity element, in the form of MnS.
However, it is more desirable in terms of twisting characteristics and low thermal expansion characteristics, and the upper limit is made 1.0%.
[0023]
P: ≦ 0.050%
P is segregated at the grain boundary and increases the intergranular corrosion susceptibility, and lowers the toughness. However, the lower limit is preferable, but the upper limit is set to 0.050% because the reduction is more than necessary. Desirably, it is 0.020% or less.
[0024]
S: ≦ 0.015%
Although S is a constituent element of a compound effective for improving the machinability, it is desirable to reduce it because the hot workability is extremely lowered, and the upper limit is made 0.015%.
[0025]
Cu: ≦ 1.0%
Cu is effective in improving the strength, but excessive addition degrades hot workability and increases thermal expansion, so 1.0% is made the upper limit.
[0026]
Ni: 35-40%
Ni is essential to ensure low thermal expansion characteristics. The range is 35 to 40%. In particular, when the low thermal expansion characteristic is important, it is desirable to set it in the range of 37 to 39%.
[0027]
Cr: ≦ 0.5%
Although Cr is effective in improving the twisting characteristics, the upper limit is set to 0.5% because the thermal expansion coefficient is increased.
[0028]
Mo: 1.5-6.0%
Mo precipitates as fine Mo 2 C or MC, M 8 C 7 type carbides, thereby improving strength and twisting characteristics. In order to ensure these characteristics, 1.5% is made the lower limit.
On the other hand, if it exceeds 6.0%, the thermal expansion characteristic may become high, so this is the upper limit.
[0029]
V: 0.05-1.0%
V, like Mo, precipitates as MC, M 8 C 7 type carbide and improves strength and twisting characteristics. The lower limit is 0.05%.
On the other hand, if added over 1.0%, coarse carbides are produced, and the twisting characteristics and toughness are deteriorated.
[0030]
O: ≦ 0.015%
Since O forms an oxide and lowers twisting properties and toughness, it is better to reduce it as much as possible, so the upper limit is made 0.015%. Desirably, it is 0.008% or less, More desirably, it is 0.003% or less.
[0031]
N: ≦ 0.03%
Since N forms nitrides and lowers twisting characteristics and toughness, it is better to reduce it as much as possible, so the upper limit is made 0.03%. Desirably, it is 0.012% or less, More desirably, it is 0.008% or less.
[0032]
Mo / V ≧ 1.0
Higher strength can be obtained by balancing Mo and V.
If this formula is satisfied, MC or M 8 C 7 type carbides with the balance of V and Mo are formed first, and Mo 2 C is formed as the value of this formula increases, And precipitates in a form effective for both twisting characteristics.
However, if it is less than 1.0, it becomes difficult to obtain high strength. Desirably 1.5 or more, and more desirably 2.5 or more.
[0033]
(0.3Mo + V) ≧ 4C
It is necessary to satisfy this formula in order to ensure stable twisting characteristics.
If there is too much C that does not form carbides of Mo and V, it is extremely difficult to obtain stable twisting characteristics although high strength can be obtained.
[0034]
W: ≤3%
W is effective for obtaining higher strength. However, excessive addition causes a decrease in hot workability, so 3% or less.
[0035]
Co: ≤3%
Basically, Co is not added because it causes an increase in cost, but may be added when higher strength is desired.
However, 3% is set as the upper limit in view of cost increase.
[0036]
Ti, Nb, Ta, Hf: ≤ 0.5%
Ti, Nb, Ta, and Hf form carbides similar to Mo and V, and are effective in improving strength and twisting characteristics. However, each of them is easy to form coarse carbides that are not effective in improving the characteristics. .5% or less.
[0037]
Ca, Mg, B, REM: 0.0005 to 0.0100%
Since Ca, Mg, B, and REM are effective elements for improving the hot workability of steel, 0.0005% may be added as the lower limit.
However, even if added excessively, the effect is saturated and conversely the hot workability is lowered, so the upper limit is made 0.0100%.
REM is made of Ce, La or their alloys.
[0038]
Next, claim 4 relates to a method for producing an Invar alloy wire. In this production method, after the Invar alloy is wire-rolled, cold working is performed in a working rate range of 20 to 75%.
This cold working is performed in order to give a preliminary strain for forming a fine and uniform carbide effective in strength and twisting characteristics in the next heat treatment stage.
[0039]
In this cold working, if the working rate is less than 20%, sufficient preliminary strain cannot be given. Conversely, if it exceeds 75%, the amount of strain becomes too large, and the recrystallization degree of the parent phase during the heat treatment in the next step. Becomes large, and it becomes difficult to obtain sufficient strength.
[0040]
In the subsequent heat treatment in the temperature range of 625 to 750 ° C., fine carbides of Mo and V are uniformly dispersed and precipitated in the parent phase, and the strength of the alloy is increased by the precipitation strengthening. This is for reducing the density and ensuring appropriate twisting characteristics.
Here, when the heat treatment temperature is less than 625 ° C., the decrease in dislocation density and carbide precipitation amount in the matrix phase is not sufficient, and conversely, when the temperature exceeds 750 ° C., the recrystallization degree of the matrix phase becomes too large, and sufficient strength It becomes difficult to obtain.
[0041]
The subsequent cold working is performed in order to ensure the necessary strength, and at that time, a working rate of 60% is required at the minimum.
Thereby, an Invar alloy wire having a tensile strength exceeding 1300 MPa is obtained.
In addition, a solution treatment may be performed at a temperature of about 1100 ° C. after the wire rod rolling, and skinning may be performed to eliminate surface scratches as appropriate during the intermediate process.
[0042]
【Example】
Next, examples of the present invention will be described in detail below.
<Example 1>
Steel having chemical components shown in Table 1 was vacuum induction melted in a high frequency induction furnace to obtain 150 kg of steel ingot. Then, this was heated to 1150 ° C. and processed into a round bar having a diameter of 65 mm by hot forging.
They were heated at 1100 ° C. and then rolled to produce a coil having a diameter of 13 mm. These materials were processed under the conditions shown in Table 1.
[0043]
Specifically, cold drawing was performed at the processing rate shown in Table 1 (drawing 1), and then heat treatment was performed under the temperature conditions shown in the same table. The heat treatment was performed for 6 hours followed by air cooling.
Next, skinning (peeling) is performed, and then cold drawing is performed at the processing rate shown in the table (drawing 2), tensile strength, twist characteristics (twist value), thermal expansion coefficient, etc. The characteristic evaluation of was performed. The results are also shown in Table 1.
[0044]
[Table 1]
<Example 2>
Steel having chemical components shown in Table 2 was melted in an electric furnace, and then AOD refining was performed to obtain a steel ingot 2.5t. After this was rolled in pieces, it was heated sufficiently at 1180 ° C. and processed into a round bar having a diameter of 13 mm by hot rolling.
These materials were processed under the conditions shown in Table 2.
[0046]
Specifically, cold drawing was performed at the processing rate shown in Table 2 (drawing 1), and then heat treatment was performed under the temperature conditions shown in the same table. The heat treatment was performed for 6 hours followed by air cooling.
Subsequently, skin cutting (peeling) was performed, and then cold wire drawing was performed at a processing rate shown in the table (drawing 2).
And they were subjected to tensile test, twist test, and low thermal expansion coefficient measurement to evaluate each characteristic. The results are also shown in Table 2.
[0047]
[Table 2]
As can be seen from the results of these examples, the examples of the present invention have good tensile strength (1300 MPa or more), twisting characteristics and low thermal expansion characteristics.
On the other hand, in the comparative example in which the values of C, Mo, V, Mo / V, and (0.3Mo + V) do not satisfy the conditions of the present invention, either or both of tensile strength and twist characteristics However, it has not been obtained with satisfactory characteristics.
[0049]
In Table 2, Comparative Examples 20 and 21 have a Si content exceeding the range of the present invention.
Thus, when the Si content exceeds the range of the present invention, the twisting characteristics are lowered.
[0050]
In Table 1, Comparative Examples 12 to 16 are examples in which the chemical conditions satisfy the conditions of Claim 1 but the manufacturing conditions do not satisfy the conditions defined in Claim 4.
In the case of these comparative examples, good characteristics are not necessarily obtained.
[0051]
For this reason, in the present invention, it is uniquely important to regulate the chemical composition of the alloy within the range defined in claim 1, thereby obtaining good strength and twisting characteristics and low thermal expansion characteristics. In this case, the manufacturing method of the Invar alloy wire is also important. In addition, the alloy components are within the range specified in claim 1 and the manufacturing conditions are the conditions specified in claim 4. This means that the most desirable result is obtained.
[0052]
Although the embodiment of the present invention has been described in detail above, this is merely an example, and the present invention can be implemented in variously modified forms without departing from the gist of the present invention.
[0053]
【The invention's effect】
As described above, according to the Invar alloy wire of the present invention, the strength, twisting property, and low thermal expansion property can all be good. Therefore, when this is used for a transmission line, the installation interval of the tower is wide, The required height of the steel tower can be reduced, and the cost for installing the steel tower can be reduced.
In addition, according to the manufacturing method of the present invention, it is possible to maximize the characteristics of the Invar alloy.
Claims (4)
C ：０．２０〜０．４０％
Si：≦０．８％
Mn：≦１．０％
P ：≦０．０５０％
S ：≦０．０１５％
Cu：≦１．０％
Ni：３５〜４０％
Cr：≦０．５％
Mo：１．５〜６．０％
V ：０．０５〜１．０％
O ：≦０．０１５％
N ：≦０．０３％であって
Mo／V≧１．０且つ（０．３Mo＋V）≧４Cであり、
残部Fe及び不可避的不純物から成る組成を有し、２０〜２３０℃までと２３０〜２９０℃までの平均線熱膨張係数が、それぞれ３．７×１０−６以下，１０．８×１０−６以下であることを特徴とする強度，捻回特性に優れたインバー合金線。% By weight
C: 0.20 to 0.40%
Si: ≦ 0.8%
Mn: ≦ 1.0%
P: ≦ 0.050%
S: ≦ 0.015%
Cu: ≦ 1.0%
Ni: 35-40%
Cr: ≦ 0.5%
Mo: 1.5-6.0%
V: 0.05-1.0%
O: ≦ 0.015%
N: ≦ 0.03%
Mo / V ≧ 1.0 and (0.3Mo + V) ≧ 4C,
It has a composition composed of the remaining Fe and inevitable impurities, and the average linear thermal expansion coefficients from 20 to 230 ° C. and from 230 to 290 ° C. are 3.7 × 10 −6 or less and 10.8 × 10 −6 or less, respectively. Invar alloy wire with excellent strength and twisting characteristics.
W ：≦３％
Co：≦３％
Ti：≦０．５％
Nb：≦０．５％
Ta：≦０．５％
Hf：≦０．５％
で含有していることを特徴とする強度，捻回特性に優れたインバー合金線。In Claim 1, 1 type (s) or 2 or more types of W, Co, Ti, Nb, Ta, and Hf are further the following ranges by weight%.
W: ≦ 3%
Co: ≤3%
Ti: ≤ 0.5%
Nb: ≤ 0.5%
Ta: ≤ 0.5%
Hf: ≤ 0.5%
Invar alloy wire with excellent strength and twisting characteristics characterized by being contained in
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| KR1020047003022A KR100910332B1 (en) | 2001-09-13 | 2002-09-11 | Invar alloy wire excellent in strength and turning characteristics and method for production thereof |
| PCT/JP2002/009243 WO2003025239A1 (en) | 2001-09-13 | 2002-09-11 | Invar alloy wire excellent in strength and turning characteristics and method for production thereof |
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| KR100884539B1 (en) * | 2008-02-18 | 2009-02-19 | 주식회사 백철금속 | Invar alloy wire with improving turning characteristics, high strength and low thermalexpansion and method for production thereof |
| CN101978086B (en) * | 2008-05-08 | 2013-07-10 | 蒂森克鲁普德国联合金属制造有限公司 | Iron-nickle alloy |
| CN102220535B (en) * | 2011-06-07 | 2013-01-23 | 江苏大学 | Zero expansion composite material |
| CN103602893A (en) * | 2013-11-11 | 2014-02-26 | 郭小平 | Hot work die steel having performance improved by adding niobium |
| CN105039850A (en) * | 2015-08-11 | 2015-11-11 | 河北钢铁股份有限公司 | High-strength and low-expansion hot-rolled invar alloy |
| JP6812461B2 (en) * | 2017-04-19 | 2021-01-13 | 山陽特殊製鋼株式会社 | High-strength low thermal expansion alloy wire |
| WO2018193809A1 (en) * | 2017-04-19 | 2018-10-25 | 山陽特殊製鋼株式会社 | High strength and low thermal expansion alloy |
| CN108396226A (en) * | 2018-04-17 | 2018-08-14 | 全球能源互联网研究院有限公司 | A kind of aerial condutor steel alloy and preparation method thereof |
| CN110541119B (en) * | 2018-05-28 | 2021-07-09 | 宝武特种冶金有限公司 | Low-expansion iron-nickel alloy and manufacturing method thereof |
| CN114107829A (en) * | 2020-09-01 | 2022-03-01 | 宝武特种冶金有限公司 | High-strength low-expansion invar alloy wire |
| CN114086086B (en) * | 2021-11-05 | 2022-07-15 | 河钢股份有限公司 | Nano-phase carbon-nitrogen composite particle reinforced invar alloy wire and preparation method thereof |
| FR3138818A1 (en) | 2022-08-09 | 2024-02-16 | Compagnie Generale Des Etablissements Michelin | Metal parts with low coefficient of thermal expansion and high mechanical resistance |
| FR3138817A1 (en) | 2022-08-09 | 2024-02-16 | Aubert & Duval | Alloy with low coefficient of thermal expansion and high mechanical resistance |
| CN115852267B (en) * | 2022-12-14 | 2024-07-12 | 河钢股份有限公司 | High-strength high-conductivity low-expansion iron-nickel-molybdenum alloy wire and production method thereof |
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| JPS61183443A (en) * | 1985-02-07 | 1986-08-16 | Daido Steel Co Ltd | Low thermal expansion material |
| JPH0570894A (en) * | 1991-09-17 | 1993-03-23 | Hitachi Metals Ltd | Alloy wire having high strength and low thermal expansion and excellent in twisting characteristic and its production |
| JPH08100242A (en) * | 1994-09-30 | 1996-04-16 | Hitachi Metals Ltd | Alloy wire with high strength, high toughness and low thermal expansion and its production |
| JP3447830B2 (en) * | 1995-01-23 | 2003-09-16 | 住友電気工業株式会社 | Invar alloy wire and method of manufacturing the same |
| JPH09316603A (en) * | 1996-05-29 | 1997-12-09 | Sumitomo Electric Ind Ltd | High strength and low thermal expansion alloy |
| JP3839957B2 (en) * | 1998-05-26 | 2006-11-01 | 住友電気工業株式会社 | High strength low thermal expansion alloy wire |
| WO2000070108A1 (en) | 1999-05-12 | 2000-11-23 | Toyo Kohan Co., Ltd. | Material for shadow mask, shadow mask and color image receiving tube having the shadow mask incorporated therein |
| JP3871894B2 (en) * | 2001-03-12 | 2007-01-24 | 山陽特殊製鋼株式会社 | Method for producing high-strength, low-thermal-expansion alloy with excellent ductility |
-
2001
- 2001-09-13 JP JP2001278806A patent/JP4797305B2/en not_active Expired - Lifetime
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2002
- 2002-09-11 WO PCT/JP2002/009243 patent/WO2003025239A1/en active Application Filing
- 2002-09-11 KR KR1020047003022A patent/KR100910332B1/en active IP Right Grant
Also Published As
| Publication number | Publication date |
|---|---|
| JP2003082439A (en) | 2003-03-19 |
| KR100910332B1 (en) | 2009-07-31 |
| KR20040041591A (en) | 2004-05-17 |
| WO2003025239A1 (en) | 2003-03-27 |
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