JP3276045B2 - Non-magnetic PC steel wire excellent in delayed fracture characteristics and method of manufacturing the same - Google Patents
Non-magnetic PC steel wire excellent in delayed fracture characteristics and method of manufacturing the sameInfo
- Publication number
- JP3276045B2 JP3276045B2 JP20131495A JP20131495A JP3276045B2 JP 3276045 B2 JP3276045 B2 JP 3276045B2 JP 20131495 A JP20131495 A JP 20131495A JP 20131495 A JP20131495 A JP 20131495A JP 3276045 B2 JP3276045 B2 JP 3276045B2
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- magnetic
- delayed fracture
- steel wire
- fracture characteristics
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Description
【0001】[0001]
【産業上の利用分野】本発明は、非磁性が要求される構
造物におけるプレストレストコンクリート(以下PCと
よぶ)用に好適な鋼材とその製造方法に関するものであ
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel material suitable for prestressed concrete (hereinafter referred to as PC) in a structure requiring non-magnetism and a method for producing the same.
【0002】[0002]
【従来の技術】従来、PC鋼は炭素鋼をベースにした鉄
鋼材料が使用されている。これらは全て磁気的に強磁性
体であるため、リニアモーターカーのガイドウェイの様
に構造物の非磁性が要求されるところには使用できな
い。また、非磁性を実現する鉄鋼材料として、Mnを1
5%程度以上添加した高Mn鋼およびオーステナイト系
のステンレス鋼が従来より知られている(特開平4−1
54938号公報、特開平4−141557号公報、特
開平4−193934号公報、特開平4−143252
号公報および特公平6−4891号公報参照)。2. Description of the Related Art Conventionally, steel materials based on carbon steel have been used for PC steel. Since these are all magnetically ferromagnetic, they cannot be used where a structure is required to be non-magnetic, such as a guideway of a linear motor car. In addition, Mn is 1 as a steel material for realizing non-magnetism.
High Mn steel and austenitic stainless steel to which about 5% or more have been added have been known (Japanese Patent Laid-Open No. 4-1).
JP-A-54938, JP-A-4-141557, JP-A-4-193934, JP-A-4-143252
And Japanese Patent Publication No. 6-4891).
【0003】[0003]
【発明が解決しようとする課題】しかし、高Mn鋼はM
nを多量に含有するため遅れ破壊特性が低下し、PC鋼
として望ましくない。また、オーステナイト系ステンレ
ス鋼にはSUS304やSUS316などがあるが、共
に冷間加工によって透磁率が上昇し、非磁性が損なわれ
るほか、PC鋼に要求される引張強度、比例限、降伏強
度、伸び、リラクセーションといった機械的特性を満足
することができないという問題があった。従って、本発
明の目的は、PC鋼としての機械的特性(引張強度、比
例限、降伏強度、伸び、リラクセーション)を満足し、
かつ遅れ破壊特性に優れた非磁性鋼材の製造方法を提供
することにある。However, high Mn steels are
Since a large amount of n is contained, the delayed fracture characteristics are deteriorated, which is not desirable as PC steel. In addition, austenitic stainless steels such as SUS304 and SUS316, both of which increase the magnetic permeability by cold working, impair non-magnetism, and have the tensile strength, proportional limit, yield strength, elongation required for PC steel However, there is a problem that mechanical properties such as relaxation cannot be satisfied. Therefore, an object of the present invention is to satisfy mechanical properties (tensile strength, proportional limit, yield strength, elongation, relaxation) as PC steel,
Another object of the present invention is to provide a method for producing a nonmagnetic steel material having excellent delayed fracture characteristics.
【0004】[0004]
【課題を解決するための手段】この目的を達成するた
め、本発明の第一の構成は、重量%でC:0.15%以
下、Si:2.0%以下、Mn:1.0%以上5.0%
未満、Ni:10.0〜13.0%、Cr:15.0〜
20.0%、N:0.1〜0.5%、残部は実質的にF
eからなる非磁性鋼材で、Ni+Mn:11〜18%、
透磁率が1.01以下、引張強度が1600N/mm2
以上、伸びが3.5%以上であることを特徴とする。そ
の製造方法は、同組成の鋼材を、断面減少率50%以上
70%以下の加工度で線引加工し、300℃以上700
℃以下、好ましくは500℃以上600℃以下に加熱す
ることを特徴とする。Means for Solving the Problems To achieve this object, a first constitution of the present invention is as follows: C: 0.15% or less, Si: 2.0% or less, Mn: 1.0% by weight %. 5.0% or more
Less, Ni: 10.0~13.0%, Cr: 15.0~
20.0%, N: 0.1 to 0.5%, the balance being substantially F
e + nonmagnetic steel material, Ni + Mn: 11 to 18%,
Permeability is 1.01 or less, tensile strength is 1600 N / mm 2
As described above, the elongation is at least 3.5%. The manufacturing method is such that a steel material having the same composition is drawn at a working ratio of 50% or more and 70% or less in cross section reduction, and 300 ° C. or more and 700 ° C. or more.
The heating is performed at a temperature of 500 ° C. or less, preferably 500 ° C. or more and 600 ° C. or less.
【0005】また、第二の構成は、重量%でC:0.1
5%以下、Si:2.0%以下、Mn:1.0%以上
5.0%未満、Ni:10.0〜13.0%、Cr:1
5.0〜20.0%、N:0.1〜0.5%、残部は実
質的にFeからなる非磁性鋼材で、Ni+Mn:11〜
18%、リラクセーション値が1.5%以下であること
を特徴とする。そして、その製造方法は、同組成の鋼材
に冷間加工を施した後、200℃〜700℃の温度に加
熱し、鋼材の破断荷重未満の引張力を与えることを特徴
とする。[0005] In the second configuration, C: 0.1% by weight is used.
5% or less, Si: 2.0% or less, Mn: 1.0% or more
Less than 5.0% , Ni: 10.0 to 13.0% , Cr: 1
5.0 to 20.0%, N: 0.1 to 0.5%, the balance is a nonmagnetic steel material substantially composed of Fe, and Ni + Mn: 11 to
18% and a relaxation value of 1.5% or less. And the manufacturing method is characterized in that after cold working a steel material having the same composition, the steel material is heated to a temperature of 200 ° C. to 700 ° C. to give a tensile force less than the breaking load of the steel material.
【0006】第三の構成は、重量%でC:0.15%以
下、Si:2.0%以下、Mn:1.0%以上5.0%
未満、Ni:10.0〜13.0%、Cr:15.0〜
20.0%、N:0.1〜0.5%、残部は実質的にF
eからなる鋼材において、次の3つの条件のうち少なく
とも一つを満たすことを特徴とする。体積%でマルテ
ンサイト量が2〜10%である。X線解析におけるf
cc(220)の半価幅が0.65以上、より好ましく
は0.7以上。100nm以下の炭化物が分散されて
いる。[0006] The third constitution is that, by weight%, C: 0.15% or less, Si: 2.0% or less, Mn: 1.0% or more and 5.0%.
Less, Ni: 10.0~13.0%, Cr: 15.0~
20.0%, N: 0.1 to 0.5%, the balance being substantially F
e, wherein at least one of the following three conditions is satisfied. The amount of martensite is 2 to 10% by volume. F in X-ray analysis
The half width of cc (220) is 0.65 or more, more preferably 0.7 or more. Carbides of 100 nm or less are dispersed.
【0007】このような鋼材の製造方法は、重量%で
C:0.15%以下、Si:2.0%以下、Mn:1.
0%以上5.0%未満、Ni:10.0〜13.0%、
Cr:15.0〜20.0%、N:0.1〜0.5%、
残部は実質的にFeからなる鋼材を線引加工した後、熱
処理する際、次の条件の少なくとも一つを満たすことを
特徴とする。線引加工を0〜100℃、より好ましく
は0〜60℃の温度域にて行う。線引加工の断面減少
率を50〜70%とする。熱処理条件を300〜60
0℃、より好ましくは500〜600℃で、10〜60
分とする。[0007] The method of manufacturing such a steel, C in weight%: 0.15% or less, Si: 2.0% or less, Mn: 1.
0% or more and less than 5.0%, Ni: 10.0 to 13.0%,
Cr: 15.0 to 20.0%, N: 0.1 to 0.5%,
The balance is characterized by satisfying at least one of the following conditions when heat-treating after drawing a steel material substantially made of Fe. The wire drawing is performed in a temperature range of 0 to 100 ° C, more preferably 0 to 60 ° C. The cross-sectional reduction rate of the drawing process is set to 50 to 70%. Heat treatment condition 300 ~ 60
0 ° C., more preferably 500-600 ° C., 10-60
Minutes.
【0008】このように、成分や製造条件を限定した理
由は次の通りである。Cはオーステナイトを安定させ、
かつ固溶強化による強度向上に寄与する元素であり非常
に重要な元素である。しかし、重量%で0.15%を越
えて含有すると炭化物が析出するため遅れ破壊特性が低
下し、延性が低下するため0.15%以下とした。Si
は脱酸剤として製造上必要とされる元素である。しか
し、一方ではフェライトの安定化元素であるため、2.
0%を越えて含有するとフェライトが生成し、非磁性が
損なわれる可能性があるためである。Mnは強力なオー
ステナイト安定化元素であり、冷間加工後の非磁性を確
保するために必要な元素である。しかし、1.0%未満
の含有量では不十分であり、15%を越えて含有する
と、線引加工性を低下させるばかりでなく遅れ破壊特性
も低下させるからである。遅れ破壊特性を考慮すると、
Mn量は1.0%以上5.0%未満が望ましい。The reasons for limiting the components and production conditions are as follows. C stabilizes austenite,
In addition, it is an element that contributes to improvement in strength by solid solution strengthening and is a very important element. However, if the content exceeds 0.15% by weight, carbides precipitate and the delayed fracture characteristics decrease, and the ductility decreases. Therefore, the content is set to 0.15% or less. Si
Is an element required for production as a deoxidizing agent. However, on the other hand, since it is a stabilizing element of ferrite, 2.
If the content exceeds 0%, ferrite is formed, and nonmagnetic properties may be impaired. Mn is a strong austenite stabilizing element, and is an element necessary for securing non-magnetism after cold working. However, if the content is less than 1.0%, it is insufficient, and if it exceeds 15%, not only the drawability but also the delayed fracture characteristics are reduced. Considering the delayed fracture characteristics,
The Mn content is desirably 1.0% or more and less than 5.0% .
【0009】NiはMn同様オーステナイト安定化元素
であり、鋼材の非磁性を確保するために有効な元素であ
る。2.0%未満ではその効果が不十分であり、15%
を越えてもそれ以上の効果はなく、コストアップを招く
だけだからである。実用上、10.0〜13.0%が好
ましい。また、MnとNiは共にオーステナイト安定化
元素であり、鋼材を確実に非磁性にするためには、Mn
+Niの量が10%以上必要である。一方、多すぎると
コストアップを招くため、11%以上18%以下が好適
である。Crは鋼材の耐食性を向上させ、かつ適量の添
加によりオーステナイトの安定化に寄与する元素である
が、過剰に含有させるとフェライトの生成を促進する。
従って、耐食性を確保する必要上、15%以上の含有量
が必要であるが、フェライトの生成を抑え、非磁性を確
保する必要上、20%以下とする必要がある。NはCと
同様にオーステナイト安定化に寄与し、固溶強化により
強度確保に必要な元素である。0.1%未満ではその効
果が小さく、0.5%を越えて含有すると製鋼時に気泡
が多量に発生し、熱間加工性を損ない、さらに遅れ破壊
特性を低下させる。Ni is an austenite stabilizing element like Mn, and is an effective element for securing non-magnetism of a steel material. If it is less than 2.0%, the effect is insufficient, and 15%
Beyond the above, there is no further effect, only cost increase. Practically, 10.0 to 13.0% is preferable. Further, both Mn and Ni are austenite stabilizing elements, and in order to make the steel material nonmagnetic,
The amount of + Ni needs to be 10% or more. On the other hand, if it is too large, the cost is increased. Therefore, the content is preferably 11% or more and 18% or less. Cr is an element that improves the corrosion resistance of steel and contributes to stabilization of austenite when added in an appropriate amount. However, when Cr is contained excessively, it promotes the formation of ferrite.
Therefore, the content is required to be 15% or more in order to ensure corrosion resistance, but it is necessary to suppress the ferrite generation and ensure non-magnetism to be 20% or less. N contributes to austenite stabilization like C, and is an element necessary for ensuring strength by solid solution strengthening. If the content is less than 0.1%, the effect is small, and if the content exceeds 0.5%, a large amount of air bubbles are generated during steel making, which impairs hot workability and further reduces delayed fracture characteristics.
【0010】また、このような組成を有する鋼材の線引
加工後の熱処理温度を300℃以上700℃以下とした
のは、非磁性PC鋼に要求される引張強度、伸びを十分
に満足する鋼材を得るためである。さらに、上記組成の
鋼材に冷間加工を施した後、破断荷重未満の引張力をか
ける際の温度条件を200℃〜700℃としたのは、前
記機械的特性の他、比例限、降伏限度を大幅に向上し、
リラクセーションを低く抑えるためである。なお、特公
昭61−53408号公報は、本発明の熱処理と同様の
熱処理を提案しているが、基本的に対象としている鋼材
の組成が異なっている。特にCの含有量に関しては同公
報記載の発明が0.2%以上であるのに対し、本願のそ
れは0.15%以下と低く、低C鋼において比例限や降
伏強度の向上を図っている点で大きく異なっている。The reason why the heat treatment temperature after drawing of the steel material having such a composition is set to 300 ° C. or more and 700 ° C. or less is that the steel material sufficiently satisfies the tensile strength and elongation required for the nonmagnetic PC steel. To get Further, the temperature conditions for applying a tensile force less than the breaking load to 200 ° C. to 700 ° C. after the cold working of the steel material having the above composition are performed in addition to the mechanical characteristics described above, in addition to the above-mentioned mechanical properties, the proportional limit and the yield limit Greatly improved
This is to keep relaxation low. JP-B-61-53408 proposes a heat treatment similar to the heat treatment of the present invention, but basically differs in the composition of the target steel material. In particular, with respect to the content of C, the invention described in the publication is 0.2% or more, whereas that of the present application is as low as 0.15% or less, and the low C steel is intended to improve the proportional limit and the yield strength. It is very different in point.
【0011】さらに、線引加工温度を0〜60℃にする
ことにより、線引後のマルテンサイト量を2〜10体積
%に、fcc(220)の半価幅を0.65以上にする
ことができる。マルテンサイト量が10%を越えて存在
すると、鋼材の透磁率が大幅に上昇し、一般に非磁性と
いわれている透磁率1.01以下の条件を逸脱する。一
方、マルテンサイト量が2%未満では、PC鋼材として
要求される強度を満足することができない。同様に、f
cc(220)の半価幅が0.65未満ではPC鋼材と
して要求される強度を満足することができない。同半価
幅が0.70以上であれば、特に強度向上効果が大き
い。Further, by setting the drawing temperature to 0 to 60 ° C., the amount of martensite after drawing to 2 to 10% by volume and the half width of fcc (220) to 0.65 or more. Can be. If the amount of martensite exceeds 10%, the magnetic permeability of the steel material increases significantly, deviating from the condition of a magnetic permeability of 1.01 or less, which is generally called non-magnetic. On the other hand, if the amount of martensite is less than 2%, the strength required as a PC steel cannot be satisfied. Similarly, f
If the half width of cc (220) is less than 0.65, the strength required as a PC steel cannot be satisfied. When the half width is 0.70 or more, the effect of improving strength is particularly large.
【0012】線引加工後の熱処理温度を300〜700
℃に限定することが引張強度や伸びの向上に寄与するこ
とは先に述べた。この熱処理条件を300〜600℃、
より好ましくは500〜600℃、加熱時間を10〜6
0分に限定することで、さらに引張強度と遅れ破壊特性
を向上させることができる。即ち、この熱処理により、
鋼材に100nm以下の微細な炭化物を分散させ、PC
鋼材として十分な強度を得ることができる。加熱時間が
60分を越えたり、加熱温度が600℃を越えたりする
と、炭化物が100nmよりも大きくなり、強度は得ら
れても遅れ破壊特性が劣る。一方、加熱時間が10分未
満であったり、加熱温度が300℃未満であったりする
と、炭化物の析出が不十分で高強度の材料が得難い。The heat treatment temperature after drawing is 300 to 700.
It was mentioned earlier that limiting the temperature to ° C. contributes to improvement in tensile strength and elongation. This heat treatment condition is 300-600 ° C.
More preferably, the heating time is 500 to 600 ° C. and the heating time is 10 to 6
By limiting the time to 0 minutes, the tensile strength and delayed fracture characteristics can be further improved. That is, by this heat treatment,
Disperse fine carbide of 100nm or less in steel
Sufficient strength can be obtained as a steel material. If the heating time exceeds 60 minutes or the heating temperature exceeds 600 ° C., the carbide becomes larger than 100 nm, and even if the strength is obtained, the delayed fracture characteristics are inferior. On the other hand, if the heating time is less than 10 minutes or the heating temperature is less than 300 ° C., the precipitation of carbides is insufficient and it is difficult to obtain a high-strength material.
【0013】[0013]
【実施例】以下、本発明の実施例を説明する。 (実施例1) 表1に示す組成の鋼材に熱間処理を行って7mmφの線
材を得た。それらを溶体化処理後、各条件で線引加工お
よび熱処理を行った。熱処理は各温度に10分間保持し
て水冷を行った。その後、透磁率、引張強度、破断伸
び、降伏強度、比例限、リラクセーションおよび遅れ破
壊特性の調査を行った。その結果を表2及び図1に示
す。Embodiments of the present invention will be described below. (Example 1) A steel material having the composition shown in Table 1 was subjected to hot treatment to obtain a wire having a diameter of 7 mm. After solution-treating them, drawing and heat treatment were performed under each condition. The heat treatment was carried out by water cooling while maintaining each temperature for 10 minutes. Thereafter, the magnetic permeability, tensile strength, elongation at break, yield strength, proportional limit, relaxation and delayed fracture characteristics were investigated. The results are shown in Table 2 and FIG.
【0014】[0014]
【表1】[Table 1]
【0015】[0015]
【表2】[Table 2]
【0016】表2は断面減少率が55%の線引加工を行
ったものを350℃で10分間加熱保持し、これを水冷
した線材に関する機械的特性の結果を示すものである。
遅れ破壊特性は、チオシアン酸アンモニウム(NH4S
CN)溶液中において、引張強度の70%の荷重をか
け、破断するまでの時間が200時間以上保持できるこ
とを条件とした。表2から分かるように、実施例中サン
プルDは冷間加工後も最も安定した磁気特性を示し、透
磁率は非常に小さい。また、引張強度、破断伸びも他の
実施例1比較例に対して高い値を示している。一方、図
1は表1のサンプルDに対して冷間加工後の熱処理にお
ける加熱温度の影響を示したものである。同図に示すよ
うに、300℃以上700℃以下の温度(特に、500
〜600℃)に加熱することによって引張強度が大幅に
向上することが確認された。Table 2 shows the results of the mechanical properties of a wire which had been subjected to wire drawing with a cross-sectional reduction rate of 55%, was heated and held at 350 ° C. for 10 minutes, and was water-cooled.
The delayed fracture characteristic is based on ammonium thiocyanate (NH 4 S
In the CN) solution, a load of 70% of the tensile strength was applied, and the condition was that the time until breaking was maintained for 200 hours or more. As can be seen from Table 2, in the Examples
Pull D shows the most stable magnetic properties even after cold working, and has very low magnetic permeability. In addition, tensile strength, elongation at break also of other
Example 1 shows a higher value than the comparative example. On the other hand, FIG. 1 shows the effect of the heating temperature in the heat treatment after the cold working on Sample D in Table 1. As shown in the figure, a temperature of 300 ° C. or more and 700 ° C. or less (in particular, 500 ° C.
To 600 ° C.), it was confirmed that the tensile strength was significantly improved.
【0017】(実施例2) 表1記載のサンプルDを用い、熱間圧延により7mmφ
の線材を作製した。その後、溶体化処理を行い、断面減
少率55%で線引加工を行って各温度に加熱し、破断荷
重の50%の荷重をかけた材料の降伏強度、比例限、リ
ラクセーションを調べた。その結果を表3に示す。(Example 2) Using sample D shown in Table 1, hot-rolled to 7 mmφ.
Was produced. Thereafter, a solution treatment was performed, a drawing process was performed at a cross-sectional reduction rate of 55%, and the material was heated to each temperature, and the yield strength, the proportional limit, and the relaxation of the material subjected to a load of 50% of the breaking load were examined. Table 3 shows the results.
【0018】[0018]
【表3】[Table 3]
【0019】表3に示すように、200℃以上700℃
以下の温度域で荷重をかけることにより、降伏強度、比
例限は大きく向上し、リラクセーションは非常に小さく
なっている。従って、PC鋼材として非常に優れている
ことが確認できた。As shown in Table 3, 200 ° C. or more and 700 ° C.
By applying a load in the following temperature range, the yield strength and the proportional limit are greatly improved, and the relaxation is very small. Therefore, it was confirmed that it was very excellent as a PC steel material.
【0020】(実施例3) さらに、表1記載のサンプルDを用い、各断面減少率で
加工を行い、350℃×10分の熱処理を行った線材の
強度と伸びを測定した。断面減少率とこれら機械的特性
の関係を図2のグラフに示す。同図に示すように、断面
減少率が高くなると、引張強度が高くなるが伸びが小さ
くなる傾向があり、断面減少率を50〜70%としたと
き、強度と靱性に優れる線材を得られることがわかる。(Example 3) Further, using the sample D shown in Table 1, processing was performed at each cross-sectional reduction ratio, and the strength and elongation of the wire rod that had been heat-treated at 350 ° C for 10 minutes were measured. The relationship between the cross-sectional reduction rate and these mechanical properties is shown in the graph of FIG. As shown in the figure, when the cross-section reduction rate increases, the tensile strength increases, but the elongation tends to decrease. When the cross-section reduction rate is 50 to 70%, a wire having excellent strength and toughness can be obtained. I understand.
【0021】(実施例4) 表4に示す組成(表1におけるサンプルDと同じ)の鋼
材を熱間圧延を行って7mmφの線材を得た。それらを
溶体化処理後、各加工温度で断面減少率56.5%の線
引加工を行った。その後、525℃にて10分間保持し
て水冷し、引張強度・透磁率・X線解析によるマルテン
サイト量・X線解析によるfcc(220)ピークの半
価幅を測定した。加工温度は、線引加工におけるダイス
出口の線材の温度とした。Example 4 A steel material having the composition shown in Table 4 (the same as Sample D in Table 1) was hot-rolled to obtain a 7 mmφ wire. After solution-treating them, wire drawing was performed at each processing temperature with a cross-sectional reduction rate of 56.5%. Thereafter, the mixture was kept at 525 ° C. for 10 minutes and cooled with water, and the tensile strength, the magnetic permeability, the amount of martensite by X-ray analysis, and the half width of the fcc (220) peak by X-ray analysis were measured. The processing temperature was the temperature of the wire at the exit of the die in the wire drawing.
【0022】[0022]
【表4】[Table 4]
【0023】その結果を図3〜6に示す。各図に示すよ
うに、加工温度の低下に伴い、マルテンサイト量・fc
c(220)ピークの半価幅(オーステナイト相中の歪
み量)が増大し、引張強度を向上できることがわかる。
加工温度100℃程度でも1600N/mm2の引張強
度か得られるが、特に60℃以下で線引加工すると、よ
り高強度の線材を得ることができる。しかし、加工温度
が0℃未満になると、マルテンサイト量の増大に伴って
透磁率の上昇を招き、非磁性材料として好ましくない。The results are shown in FIGS. As shown in each figure, as the processing temperature decreases, the amount of martensite / fc
It can be seen that the half width of the c (220) peak (the amount of strain in the austenite phase) increases, and the tensile strength can be improved.
Although a tensile strength of 1600 N / mm 2 can be obtained even at a processing temperature of about 100 ° C., a wire having a higher strength can be obtained particularly by drawing at 60 ° C. or lower. However, when the processing temperature is lower than 0 ° C., the magnetic permeability increases with an increase in the amount of martensite, which is not preferable as a nonmagnetic material.
【0024】(実施例5) 表4に示す組成の鋼材を熱間圧延を行って7mmφの線
材を得た。それらを溶体化処理後、50〜55℃で断面
減少率56.5%の線引加工を行った。その後、種々の
条件で熱処理を行い、引張強度・炭化物の析出状況・遅
れ破壊特性を評価した。遅れ破壊特性は、0.1規定の
HCl溶液を腐食液として破断荷重の80%の荷重で試
験し、試験時間は最大200時間とした。実施例1では
主にHによる遅れ破壊特性を調べたが、本例ではさらに
Cl−の腐食による遅れ破壊特性も調べている。その結
果を表5に示す。Example 5 A steel material having the composition shown in Table 4 was hot-rolled to obtain a 7 mmφ wire. After solution-treating them, drawing was performed at 50 to 55 ° C. with a cross-sectional reduction rate of 56.5%. Thereafter, heat treatment was performed under various conditions to evaluate tensile strength, carbide precipitation, and delayed fracture characteristics. The delayed fracture characteristics were tested using a 0.1N HCl solution as a corrosive liquid at a load of 80% of the breaking load, and the test time was set to a maximum of 200 hours. In Example 1, mainly the delayed fracture characteristics due to H were examined, but in this example, the delayed fracture characteristics due to Cl − corrosion were also investigated. Table 5 shows the results.
【0025】[0025]
【表5】[Table 5]
【0026】同表に示すように、加熱温度が300〜7
00℃の範囲で、1600N/mm2以上の引張強度が
得られていることがわかる。特に、加熱温度を500〜
600℃にすると、微細な炭化物が析出され、引張強度
の向上が顕著に認められる。また、加熱時間を10〜6
0分とすれば、高い引張強度と優れた遅れ破壊特性を具
えた線材を得ることができた。加熱温度が高すぎたり、
加熱時間が長すぎると、析出炭化物が大きくなり、引張
強度は高くても遅れ破壊特性が劣る。As shown in the table, the heating temperature was 300 to 7
It can be seen that a tensile strength of 1600 N / mm 2 or more was obtained in the range of 00 ° C. Particularly, when the heating temperature is 500 to
At 600 ° C., fine carbides are precipitated, and improvement in tensile strength is remarkably recognized. In addition, the heating time is 10 to 6
At 0 minutes, a wire having high tensile strength and excellent delayed fracture characteristics could be obtained. The heating temperature is too high,
If the heating time is too long, the precipitated carbides become large and the delayed fracture characteristics are inferior even if the tensile strength is high.
【0027】(実施例6) 表6に示す組成の鋼材に熱間圧延を行って7mmφの線
材を得た。それらを溶体化処理後、各加工温度で断面減
少率56.5%の線引加工を行った。その後、525℃
にて10分間保持して水冷し、得られた線材の遅れ破壊
特性を評価した。評価は実施例5と同様の方法で行っ
た。その結果を表7に示す。同表から明らかなように、
実施例は参考例に比べて極めて優れた遅れ破壊特性を示
すことがわかる。Example 6 A steel material having the composition shown in Table 6 was hot-rolled to obtain a 7 mmφ wire. After solution-treating them, wire drawing was performed at each processing temperature with a cross-sectional reduction rate of 56.5%. Then 525 ° C
For 10 minutes, and water-cooled, and the delayed fracture characteristics of the obtained wire were evaluated. The evaluation was performed in the same manner as in Example 5. Table 7 shows the results. As is clear from the table,
It can be seen that the examples show extremely excellent delayed fracture characteristics as compared with the reference example.
【0028】[0028]
【表6】[Table 6]
【0029】[0029]
【表7】[Table 7]
【0030】[0030]
【発明の効果】以上説明したように、本発明により非磁
性PC鋼に要求される機械的特性を満足する鋼材を得る
ことができる。特に請求項1記載の鋼材は、透磁率、引
張強度、伸びおよび遅れ破壊に優れている。また、請求
項3記載の鋼材は、これらの機械的特性に加えて、降伏
強度、比例限およびリラクセーションに優れている。さ
らに、請求項5〜7記載の鋼材も、引張強度に優れ、低
透磁率を実現できる。特に請求項7記載の鋼材は、遅れ
破壊特性に優れている。従って、リニアモーターカーの
ガイドウェイや核磁気共鳴断層室などの非磁性が要求さ
れる構造物においてPC鋼とし利用することができる。As described above, according to the present invention, it is possible to obtain a steel material satisfying the mechanical properties required for a non-magnetic PC steel. In particular, the steel material according to claim 1 is excellent in magnetic permeability, tensile strength, elongation and delayed fracture. Further, in addition to these mechanical properties, the steel material according to claim 3 is excellent in yield strength, proportional limit, and relaxation. Furthermore, the steel materials according to claims 5 to 7 are also excellent in tensile strength and can realize low magnetic permeability. Particularly, the steel material according to claim 7 is excellent in delayed fracture characteristics. Therefore, it can be used as PC steel in a structure requiring non-magnetism such as a guideway of a linear motor car and a nuclear magnetic resonance tomography room.
【図1】熱処理温度と引張強度の関係を示すグラフであ
る。FIG. 1 is a graph showing a relationship between a heat treatment temperature and a tensile strength.
【図2】断面減少率と機械的特性の関係を示すグラフで
ある。FIG. 2 is a graph showing a relationship between a cross-sectional reduction rate and mechanical characteristics.
【図3】線引加工温度と引張強度の関係を示すグラフで
ある。FIG. 3 is a graph showing a relationship between drawing temperature and tensile strength.
【図4】線引加工温度と透磁率の関係を示すグラフであ
る。FIG. 4 is a graph showing a relationship between drawing temperature and magnetic permeability.
【図5】線引加工温度とマルテンサイト量の関係を示す
グラフである。FIG. 5 is a graph showing the relationship between the drawing temperature and the amount of martensite.
【図6】線引加工温度とfcc(220)ピークの関係
を示すグラフである。FIG. 6 is a graph showing the relationship between drawing temperature and fcc (220) peak.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平5−271768(JP,A) 特開 昭57−98625(JP,A) 特開 平6−212358(JP,A) ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-271768 (JP, A) JP-A-57-98625 (JP, A) JP-A-6-212358 (JP, A)
Claims (8)
2.0%以下、Mn:1.0%以上5.0%以下(5.0
%を除く)、Ni:10.0〜13.0%、Cr:1
5.0〜20.0%、N:0.1〜0.5%、残部は実
質的にFeからなり、100nm以下の炭化物が分散され
ており、透磁率が1.01以下、破断強度が1600N/
mm2以上、伸びが3.5%以上であることを特徴とする
遅れ破壊特性に優れた非磁性PC鋼線材。C. 0.1% or less by weight of C, Si:
2.0% or less, Mn: 1.0% or more and 5.0% or less (5.0 % or less)
%) , Ni: 10.0 to 13.0%, Cr: 1
5.0 to 20.0%, N: 0.1 to 0.5%, balance substantially consists of Fe, and carbides of 100 nm or less are dispersed.
With a magnetic permeability of 1.01 or less and a breaking strength of 1600 N /
mm 2 or more and elongation of 3.5% or more
Non-magnetic PC steel wire with excellent delayed fracture characteristics .
10%であることを特徴とする請求項1記載の遅れ破壊
特性に優れた非磁性PC鋼線材。2. A further amount of martensite is 2% by volume
2. The delayed fracture according to claim 1 , wherein the rate is 10%.
Non-magnetic PC steel wire with excellent properties .
幅が0.65以上であることを特徴とする請求項1また
は2記載の遅れ破壊特性に優れた非磁性PC鋼線材。3. Further, also claim 1, wherein the half width of the fcc (220) in X-ray diffraction is 0.65 or more
Is a non-magnetic PC steel wire excellent in delayed fracture characteristics as described in 2 .
下であることを特徴とする請求項1〜3のいずれかに記載
の遅れ破壊特性に優れた非磁性PC鋼線材。 4. The method according to claim 1 , wherein the relaxation value is 1.5% or less.
The method according to claim 1, wherein:
Non-magnetic PC steel wire with excellent delayed fracture characteristics.
2.0%以下、Mn:1.0%以上5.0%以下(5.
0%を除く)、Ni:10.0〜13.0%、Cr:1
5.0〜20.0%、N:0.1〜0.5%、残部は実
質的にFeからなる鋼材を、0〜100℃の温度域で線
引加工し、その後、500〜600℃の温度域で、10
〜60分加熱する熱処理を施すことを特徴とする遅れ破
壊特性に優れた非磁性PC鋼線材の製造方法。5. C: 0.15% or less by weight%, Si:
2.0% or less, Mn: 1.0% or more and 5.0% or less (5.
0%) , Ni: 10.0 to 13.0%, Cr: 1
5.0 to 20.0%, N: 0.1 to 0.5%, balance being substantially Fe, steel wire is drawn in a temperature range of 0 to 100 ° C. , and then 500 to 600 ° C. In the temperature range of 10
Delayed heat treatment by heating for up to 60 minutes
Manufacturing method of non-magnetic PC steel wire with excellent breaking characteristics .
であることを特徴とする請求項5記載の遅れ破壊特性に
優れた非磁性PC鋼線材の製造方法。6. The degree of wire drawing is 50 to 70% in terms of cross-sectional reduction rate.
The delayed fracture characteristic according to claim 5 , wherein
Excellent non-magnetic PC steel wire manufacturing method.
とを特徴とする請求項5または6記載の遅れ破壊特性に優
れた非磁性PC鋼線材の製造方法。 7. The temperature range of the drawing process is 0 to 60 ° C.
7. Excellent in delayed fracture characteristics according to claim 5 or 6.
Manufacturing method of non-magnetic PC steel wire.
度に加熱し、鋼材の破断荷重未満の引張力を与えること
に置換することを特徴とする請求項5〜7のいずれかに記
載の遅れ破壊特性に優れた非磁性PC鋼線材の製造方法。 8. The heat treatment is performed at a temperature of 200 ° C. to 700 ° C.
To a tensile strength less than the breaking load of steel
The method according to any one of claims 5 to 7, wherein
Manufacturing method of non-magnetic PC steel wire with excellent on-load delayed fracture characteristics.
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JP6-274453 | 1994-10-12 | ||
JP27445394 | 1994-10-12 | ||
JP20131495A JP3276045B2 (en) | 1994-10-12 | 1995-07-13 | Non-magnetic PC steel wire excellent in delayed fracture characteristics and method of manufacturing the same |
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JP11222661A Division JP2000038642A (en) | 1994-10-12 | 1999-08-05 | Nonmagnetic steel and its production |
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JP6126881B2 (en) * | 2013-03-22 | 2017-05-10 | 新日鐵住金ステンレス株式会社 | Stainless steel wire excellent in torsion workability and manufacturing method thereof, and stainless steel wire rod and manufacturing method thereof |
KR101674835B1 (en) * | 2015-12-07 | 2016-11-10 | 주식회사 포스코 | High strength wire rod having excellent corrosion resistance and method for manufacturing thereof |
CN109623198B (en) * | 2019-01-03 | 2020-12-18 | 南京钢铁股份有限公司 | Welding wire for submerged-arc welding of high-manganese low-temperature steel and welding method |
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