JPH05105957A - Production of heat resistant high strength bolt - Google Patents
Production of heat resistant high strength boltInfo
- Publication number
- JPH05105957A JPH05105957A JP27095791A JP27095791A JPH05105957A JP H05105957 A JPH05105957 A JP H05105957A JP 27095791 A JP27095791 A JP 27095791A JP 27095791 A JP27095791 A JP 27095791A JP H05105957 A JPH05105957 A JP H05105957A
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- Prior art keywords
- steel
- strength
- bolt
- resistant high
- temperature
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- Heat Treatment Of Steel (AREA)
- Heat Treatment Of Articles (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、建築、土木等の分野に
おける各種構造物の締結用ボルトに使用して好適な耐熱
性高強度ボルト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 method for producing a heat resistant high strength bolt suitable for use as a fastening bolt for various structures in the fields of construction, civil engineering and the like.
【０００２】[0002]
【従来の技術】従来、建築、土木等の分野における各種
構造物用材料としては、一般構造用圧延鋼材（JIS G 31
01）、溶接構造用圧延鋼材（JIS G 3106）及び溶接構造
用耐候性熱間圧延鋼材（JIS G3114）などが広く使用さ
れ, またこれらの締結用ボルトとしては近年、高力六角
ボルト、高力トルシア形ボルトなどが広く用いられてい
る。2. Description of the Related Art Conventionally, general structural rolled steel (JIS G 31
01), rolled steel for welded structures (JIS G 3106) and weather-resistant hot rolled steel for welded structures (JIS G3114) are widely used. In addition, these fastening bolts have recently been high-strength hexagon bolts and high-strength bolts. Torsia type bolts are widely used.
【０００３】上述したとおり、各種建築構造物には上記
のような鋼材が使用されるが, これらの鋼材は 350℃以
上の高温にさらされると耐力が著しく低下し, 建築物の
破壊を招くおそれがある。そのため建築物に火災が発生
しても, 鋼材の温度が 350℃を超えないように耐火被覆
を施工することが義務付けられている。しかしながら、
このような耐火被覆の実施は, 施工コストを上昇させる
だけでなく、柱材などの占有面積の増大を招き、居住空
間の有効利用を阻害する。そこで、このような耐火被覆
処理の軽減または削減を図るべく、高温においても高い
耐力を有する鋼材の開発が精力的に進められている（例
えば特開平２−170943号公報、特開平２−254134号公報
等）。As mentioned above, the above-mentioned steel materials are used for various building structures. However, when these steel materials are exposed to a high temperature of 350 ° C. or higher, the yield strength is remarkably reduced, which may lead to the destruction of the building. There is. Therefore, even if a fire occurs in a building, it is obligatory to apply a fireproof coating so that the temperature of steel does not exceed 350 ℃. However,
The implementation of such fireproof coating not only raises the construction cost but also increases the area occupied by pillars and the like, which hinders the effective use of the living space. Therefore, in order to reduce or reduce such refractory coating treatment, development of steel materials having high proof stress even at high temperature has been vigorously pursued (for example, Japanese Patent Laid-Open Nos. 2-170943 and 2-254134). Gazette).
【０００４】また、これらの構造物は、通常、上記した
ような高力ボルト及びナットで締結されるが、かかる締
結用ボルトについても、鋼材と同様、常温、高温時にお
いても充分な強度及び靭性を備えることが要求される。
そのため従来は、かような高力ボルト等についても耐火
性を確保するため、入念な耐火被覆が必要とされてい
た。Further, these structures are usually fastened with the high-strength bolts and nuts as described above, and these fastening bolts have sufficient strength and toughness at room temperature and high temperature as well as steel materials. Is required to be provided.
Therefore, in the past, in order to secure the fire resistance even for such high strength bolts and the like, careful fireproof coating has been required.
【０００５】従って、締結用ボルトについても、鋼材と
同様、耐火性の向上が強く求められている。また、近
年、建築物や構造物は大型化の傾向にあることから、で
きる限り重量を軽減すべく、鋼材については勿論のこと
締結用ボルトについても高強度化が要望されている。し
かし、その高強度化は、一方で遅れ破壊の問題を招き、
それ故にかかる弊害なしに高強度化を図るためには、強
度と共に靭性を高めることが重要となる。Therefore, the fastening bolts are also strongly required to have improved fire resistance, as with steel materials. Further, in recent years, since buildings and structures tend to be large, there is a demand for higher strength not only for steel materials but also for fastening bolts in order to reduce the weight as much as possible. However, the increase in strength leads to the problem of delayed fracture,
Therefore, it is important to increase the toughness as well as the strength in order to increase the strength without the adverse effect.
【０００６】[0006]
【発明が解決しようとする課題】そこで、発明者らは、
上記問題点を解決すべく、現状のＦ10Ｔクラスの中炭素
−Cr鋼（ 0.2％Ｃ− 0.7％Mn− 0.6％Cr−Ｂ系）のボル
トについて、その高温耐力を調査した。ここにＦ10Ｔ
は、熱延ままではフェライト＋パーライト組織である
が、引き抜き加工後、焼き入れ−焼き戻し処理を行うこ
とにより、110 kgf/mm 2 程度の引っ張り強さ（T.S.）が
得られる。なお火災時の高温耐力については、通常 600
℃における耐力が問題とされるので、この実験では室温
から 700℃までの温度範囲における強度及び耐力につい
て調査した。その結果を表１に示す。Therefore, the inventors have
In order to solve the above problems, the current F10T class medium carbon
-Cr steel (0.2% C-0.7% Mn-0.6% Cr-B system)
The high temperature proof stress was investigated. F10T here
Is a ferrite + pearlite structure as hot rolled
However, after drawing, quenching-tempering
Depending on, 110 kgf / mm 2Tensile strength (T.S.)
can get. Regarding the high temperature proof stress in a fire, it is usually 600
Since proof stress at ℃ is a problem, room temperature is used in this experiment.
Strength and proof stress in the temperature range from 1 to 700 ℃
I investigated. The results are shown in Table 1.
【０００７】[0007]
【表１】 [Table 1]
【０００８】表１から明らかなように、両特性とも 400
℃を超えると急激に低下し、 600℃における耐力は15 k
gf/mm2と低く, 常温の1/7 程度となる。As is clear from Table 1, both characteristics are 400
When the temperature exceeds ℃, it drops sharply and the proof stress at 600 ℃ is 15 k.
It is as low as gf / mm 2, which is about 1/7 of room temperature.
【０００９】そこで高温耐力及び高温強度に及ぼす成分
組成の影響について研究を重ねた。その結果、Moを適量
添加することに想い到った。図１に、中炭素−Cr鋼にMo
を添加した場合の高温引っ張り特性について調べた結果
を示したが、同図に示したとおり、Moの添加によって高
温耐力及び高温強度とも向上する。Therefore, studies were repeatedly conducted on the influence of the composition of components on the high temperature proof stress and the high temperature strength. As a result, they came up with the idea of adding an appropriate amount of Mo. Fig. 1 shows that Mo is added to medium carbon-Cr steel.
The results of examination on the high temperature tensile properties in the case of adding Mo are shown. As shown in the figure, the addition of Mo improves both the high temperature yield strength and the high temperature strength.
【００１０】しかし一方で、Moの添加によって焼き入れ
性が向上し、熱間圧延後の冷却過程でベイナイトを主体
とした組織となり硬化する結果、加工性が劣化するとい
う問題が生じた。また、ボルトは一般に、熱間圧延材を
球状化焼鈍した後、伸線加工ついでボルト成形加工が施
され、最後に焼き入れ−焼き戻し処理を行うことによっ
て所定の強度、靭性を得るのであるが、Mo添加材は、球
状化焼鈍により生成するMo系の炭化物がその後の溶体化
処理において固溶し難く、最終工程の焼き入れ温度に加
熱しても未固溶炭化物として多量に残存し、これが靭性
を大きく劣化させる原因となっていることが判明した。On the other hand, however, the addition of Mo improves the hardenability, and in the cooling process after hot rolling, the structure becomes mainly bainite and hardens. As a result, the workability deteriorates. Further, a bolt is generally obtained by subjecting a hot rolled material to spheroidizing annealing, followed by wire drawing and then bolt forming, and finally by quenching-tempering to obtain predetermined strength and toughness. , Mo-added material, Mo-based carbide generated by spheroidizing annealing is difficult to form a solid solution in the subsequent solution treatment, a large amount remains as undissolved carbide even when heated to the quenching temperature of the final step, this It was found to be the cause of a large deterioration in toughness.
【００１１】そこで発明者らは, 上記問題を解決すべ
く、鋭意研究を重ねた結果、(1) 熱間圧延後、一旦巻き
取り、圧延顕熱を利用してその後の冷却を緩やかにすれ
ば、たとえMoを含有していても、ベイナイトの生成を効
果的に抑制することができること、(2) 従来不可欠とさ
れた球状化焼鈍を省略できること、(3) 球状化焼鈍を省
略できるので、Mo添加鋼において靭性の劣化原因となっ
ていた未固溶炭化物による悪影響が解消されること、の
知見を得た。本発明は、上記の知見に立脚するものであ
る。[0011] Therefore, as a result of intensive studies to solve the above problems, the present inventors have found that (1) after hot rolling, once winding and using sensible heat of rolling to slow the cooling thereafter. , Even if it contains Mo, it is possible to effectively suppress the formation of bainite, (2) the spheroidizing annealing, which was conventionally indispensable, can be omitted, and (3) the spheroidizing annealing can be omitted. It was found that the adverse effect of undissolved carbide, which was the cause of deterioration of toughness in the added steel, is eliminated. The present invention is based on the above findings.
【００１２】すなわち、本発明は、Ｃ：0.15〜0.40wt％
（以下単に％で示す），Si：0.5 ％以下，Mn：0.30〜1.
50％，Cr：0.30〜1.50％，Mo：0.30〜0.70％，Ti：0.00
5 〜0.050 ％，Al：0.005 〜0.050 ％及びＢ：0.0005〜
0.0030％を含み、残部はFe及び不可避的不純物からなる
鋼材を、熱間圧延後, 巻き取り温度から 600℃までを20
0℃／ｈ以下の速度で冷却し、ついで伸線加工後、ボル
ト成形加工を施したのち、焼き入れ−焼き戻し処理を施
すことを特徴とする靭性の高い耐熱性高強度ボルトの製
造方法（第１発明）である。That is, according to the present invention, C: 0.15 to 0.40 wt%
(Hereinafter simply expressed as%), Si: 0.5% or less, Mn: 0.30 to 1.
50%, Cr: 0.30 to 1.50%, Mo: 0.30 to 0.70%, Ti: 0.00
5 to 0.050%, Al: 0.005 to 0.050% and B: 0.0005 to
A steel material containing 0.0030% and the balance Fe and unavoidable impurities was hot-rolled, and the temperature from the coiling temperature to 600 ° C
A method for producing a heat-resistant high-strength bolt having high toughness, which comprises cooling at a rate of 0 ° C./h or less, then performing wire drawing, bolt forming, and then quenching-tempering ( The first invention).
【００１３】また、本発明は、第１発明において、鋼材
が、上記の鋼組成に加え、Ｖ：0.03〜0.20％，Nb：0.00
5 〜0.04％及びNi：0.10〜0.50％のうちから選んだ１種
又は２種以上を含む組成になる耐熱性高強度ボルトの製
造方法（第２発明）である。According to the first aspect of the present invention, in addition to the above steel composition, the steel material is V: 0.03 to 0.20%, Nb: 0.00
A heat-resistant high-strength bolt manufacturing method (second invention) having a composition containing one or more selected from 5 to 0.04% and Ni: 0.10 to 0.50%.
【００１４】[0014]
【作用】以下、本発明の構成要件について詳細に説明す
る。まず本発明において、鋼材の成分組成を上記の範囲
に限定した理由について説明する。 Ｃ：0.15〜0.40％ Ｃは、焼き入れ−焼き戻し処理によって得られる所定の
引っ張り強さを確保するために不可欠な元素であるが、
0.15％未満ではその効果が不十分で必要な引っ張り強さ
が得られず、一方 0.4％を超えると十分な強度は得られ
るものの、延性が低下して遅れ破壊感受性が増大するの
で、0.15〜0.40％の範囲に限定した。The constituent features of the present invention will be described in detail below. First, in the present invention, the reason why the composition of the steel material is limited to the above range will be described. C: 0.15 to 0.40% C is an indispensable element for securing a predetermined tensile strength obtained by quenching-tempering treatment,
If it is less than 0.15%, the effect is insufficient and the required tensile strength cannot be obtained. On the other hand, if it exceeds 0.4%, sufficient strength is obtained, but ductility decreases and delayed fracture susceptibility increases, so 0.15 to 0.40 It was limited to the range of%.
【００１５】Si：0.5 ％以下 Siは、脱酸作用及び固溶強化作用が強いという利点があ
る反面、ボルト成形時における変形抵抗の増大を招き、
また粒界酸化を招来するという不都合もあるので、0.5
％以下の範囲で含有させるものとした。Si: 0.5% or less Si has the advantage that it has a strong deoxidizing action and solid solution strengthening action, but on the other hand, it causes an increase in deformation resistance during bolt forming.
In addition, there is a disadvantage that it causes grain boundary oxidation, so 0.5
%, And the content should be contained within the range.
【００１６】Mn：0.30〜1.50％ Mnは、脱酸に有効に寄与するだけでなく、焼入れ性を高
め高強度を発現させる有用元素であるが、0.30％未満で
はその効果に乏しく、一方1.50％を超えると冷間加工性
が劣化するだけでなく、偏析が助長されるで、0.30〜1.
50％の範囲で含有させるものとした。Mn: 0.30 to 1.50% Mn is a useful element that not only effectively contributes to deoxidation but also enhances hardenability and develops high strength, but if it is less than 0.30%, its effect is poor, while 1.50%. If it exceeds 0.30, not only cold workability is deteriorated but also segregation is promoted, so that 0.30 to 1.
It was made to contain in the range of 50%.
【００１７】Cr：0.30〜1.50％ Crは、焼入れ性を高め、強度を向上させる有用元素であ
り、そのためには少なくとも0.30％を必要とするが、1.
50％を超えて多量に添加すると変形抵抗が増大し加工性
が阻害されるので、0.30〜1.50％の範囲で含有させるも
のとした。Cr: 0.30 to 1.50% Cr is a useful element that enhances hardenability and strength. For that purpose, at least 0.30% is required, but 1.
If added in excess of 50%, the deformation resistance increases and the workability is impaired, so the content was made 0.30 to 1.50%.
【００１８】Mo：0.30〜0.70％ Moは、本発明の主要目的の一つである高温強度を確保す
るのに不可欠な元素であり、 600℃での高温強度を高く
するためには少なくとも0.30％を必要とする。しかし、
0.70％を超えて多量に添加すると加工性が阻害されるだ
けでなく、高価となるので、0.30〜0.70％の範囲で含有
させるものとした。Mo: 0.30 to 0.70% Mo is an essential element for ensuring high temperature strength, which is one of the main purposes of the present invention, and at least 0.30% Mo for increasing high temperature strength at 600 ° C. Need. But,
If it is added in a large amount exceeding 0.70%, not only the workability is impaired but also it becomes expensive, so the content was made 0.30 to 0.70%.
【００１９】Ti：0.005 〜0.050 ％ Tiは、Ｎと結合して窒化物を形成し、結晶粒を微細化さ
せて靭性を高める有用元素である。また、Ｎを固定する
ことによってBNの生成を抑制し、有効Ｂ量を確保するこ
とにより、強度の向上にも有効に寄与する。しかし、
0.005％に満たないとその効果が充分でなく、一方、 0.
050％を超えて添加してもその効果は飽和に達するの
で、 0.005〜0.050 ％の範囲で含有させるものとした。Ti: 0.005 to 0.050% Ti is a useful element that combines with N to form a nitride and refines the crystal grains to enhance the toughness. Further, by fixing N, the generation of BN is suppressed and the effective B amount is secured, which effectively contributes to the improvement of strength. But,
If it is less than 0.005%, the effect is not sufficient, while on the other hand, it is 0.
Even if added over 050%, the effect reaches saturation, so the content was made 0.005 to 0.050%.
【００２０】Al：0.005 〜0.050 ％ Alは、Tiと同様、結晶粒の微細化に有効に寄与するが、
0.005％未満ではその効果が発揮されず、一方、 0.050
％を超えて添加するとアルミナ系介在物の生成が促進さ
れて清浄度が劣化するので、 0.005〜0.050 ％の範囲で
含有させるものとした。Al: 0.005-0.050% Al, like Ti, effectively contributes to the refinement of crystal grains,
If it is less than 0.005%, the effect is not exhibited, while on the other hand, 0.050
%, The generation of alumina inclusions is promoted and the cleanliness deteriorates, so the content was made 0.005 to 0.050%.
【００２１】Ｂ：0.0005〜0.0030％ Ｂは、粒界を清浄にして遅れ破壊感受性を低下させる有
用元素である。しかし0.0005未満ではその効果が十分に
は発揮されず、一方、0.0030％を超えて多量に添加する
と粗大なBNが析出し、靭性が劣化するので、Ｂは0.0005
〜0.0030％の範囲で含有させるものとした。B: 0.0005 to 0.0030% B is a useful element that cleans grain boundaries and reduces delayed fracture susceptibility. However, if it is less than 0.0005, the effect is not sufficiently exhibited, while if it is added in excess of 0.0030%, coarse BN precipitates and the toughness deteriorates, so B is 0.0005.
To 0.0030%.
【００２２】以上、基本成分について説明したが、本発
明では、さらに高温強度及び靭性を向上させるために、
以下の元素を添加することができる。Ｖ：0.03〜0.20％ Ｖは、焼入れ性の向上及び析出強化に有効に寄与するだ
けでなく、高温強度の改善にも有用な元素であり、これ
らの効果を発揮させるためには少なくとも0.03％の添加
を必要とする。しかし、0.20％を超えて多量に添加して
もその効果は飽和に達するので上限は0.20％に定めた。Although the basic components have been described above, in the present invention, in order to further improve high temperature strength and toughness,
The following elements can be added. V: 0.03 to 0.20% V is an element that not only effectively contributes to the improvement of hardenability and precipitation strengthening, but is also useful for the improvement of high temperature strength. In order to exert these effects, at least 0.03% of V is used. Requires addition. However, even if added in a large amount exceeding 0.20%, the effect reaches saturation, so the upper limit was set to 0.20%.
【００２３】Nb：0.005 〜0.04％ Nbも、Tiと同様に、結晶粒を微細化させ、靭性の向上に
有効に寄与する元素であるが、 0.005％未満ではその効
果が認められず、一方、0.04％を超える多量添加は炭窒
化物の増加を招きかえって靭性を劣化させるので、 0.0
05〜0.04％の範囲で含有させるものとした。Nb: 0.005 to 0.04% Nb is also an element which, like Ti, makes the crystal grains finer and effectively contributes to the improvement of toughness, but if it is less than 0.005%, its effect is not recognized. Addition of a large amount exceeding 0.04% causes an increase in carbonitrides and deteriorates toughness.
The content was set to be in the range of 05 to 0.04%.
【００２４】Ni：0.10〜0.50％ Niも、靭性を向上させる有用元素であるが、0.10％に満
たないとその効果に乏しく、一方、0.50％を超えて添加
してもその効果は飽和に達し、また高価ともなるので、
0.10〜0.50％の範囲で添加するものとした。Ni: 0.10 to 0.50% Ni is also a useful element for improving toughness, but if it is less than 0.10%, its effect is poor, while if it is added in excess of 0.50%, its effect reaches saturation. , Because it will also be expensive,
It was supposed to be added in the range of 0.10 to 0.50%.
【００２５】さて、上記の好適成分組成に調整された鋼
材は、熱間圧延により所定寸法の丸棒に圧延された後、
巻き取られる。ここに本発明鋼は焼き入れ性が高いの
で、軟化させるためには低温加熱、低温巻き取りが好ま
しく、とくに巻き取り温度は850〜750 ℃程度とするの
が望ましい。巻き取り後、パーライト変態を完了させる
必要があるが、このパーライト変態には巻き取り後の冷
却速度が最も強く影響し、200 ℃／ｈ以下でないとベイ
ナイト組織の生成を抑制できない。そこで本発明では、
巻き取り後の冷却速度は 200℃／ｈ以下に限定したので
ある。なお、パーライト変態完了後は特に冷却速度を規
制する必要はないので、かかる制御冷却を施すべき下限
温度はパーライト変態が完了する 600℃に限定した。な
お、巻き取り後の冷却速度が、上記の速度より速くて
も、ベイナイト変態後に再加熱し、溶体化した後、 200
℃／ｈ以下の冷却速度で冷却しても同様の効果が得られ
る。Now, the steel material adjusted to the above-mentioned preferable composition is rolled into a round bar of a predetermined size by hot rolling,
It is rolled up. Since the steel of the present invention has high hardenability, low temperature heating and low temperature winding are preferable for softening, and the winding temperature is preferably about 850 to 750 ° C. It is necessary to complete the pearlite transformation after winding, but the cooling rate after winding has the strongest effect on this pearlite transformation, and the formation of bainite structure cannot be suppressed unless it is 200 ° C./h or less. Therefore, in the present invention,
The cooling rate after winding was limited to 200 ° C / h or less. Since it is not necessary to control the cooling rate after the completion of pearlite transformation, the lower limit temperature for performing such controlled cooling was limited to 600 ° C at which pearlite transformation was completed. Even if the cooling rate after winding is faster than the above rate, after reheating after bainite transformation and solution heat treatment, 200
The same effect can be obtained by cooling at a cooling rate of ° C / h or less.
【００２６】ついで熱間圧延丸棒を、常法に従い伸線加
工後、ボルトに成形加工する。ここに、伸線加工は、素
材をボルトの呼び径にスキンパス伸線し、またボルト成
形加工は、冷間において通常の条件下に行うのが好まし
い。Then, the hot-rolled round bar is drawn into a bolt by a conventional method. Here, the wire drawing is preferably performed by skin-pass drawing the material into the nominal diameter of the bolt, and the bolt forming is preferably performed under normal conditions in the cold.
【００２７】さらにボルト成形加工後、焼き入れ−焼き
戻し処理による調質処理を施す。焼き入れ条件は、 850
〜950 ℃に加熱後、冷却するのが望ましい。また焼き戻
し条件は、所定の特性になるように組成との組み合わせ
で選択されるが、良好な靭性を得るためには 450〜550
℃の温度範囲における焼き戻し処理が望ましい。Further, after the bolt forming process, a tempering process by quenching-tempering process is applied. Quenching conditions are 850
It is desirable to cool after heating to ~ 950 ° C. The tempering conditions are selected in combination with the composition so that the specified characteristics are achieved, but in order to obtain good toughness, it is 450-550.
A tempering treatment in the temperature range of ° C is desirable.
【００２８】[0028]
【実施例】表２に示す種々の化学組成になる鋼材（Ａ〜
Ｈ） 100kgを、それぞれ真空溶解炉で溶製したのち、15
0 mm角に鍛造した。ついで、熱間圧延により20mmφのバ
ーインコイルに仕上げた後、 800℃で巻き取り、その後
600℃まで 100℃／ｈの速度で冷却した。なお、一部に
ついては比較のため空冷とした。得られた鋼材のうちＡ
〜Ｅ鋼について、圧延後の機械的性質について調べた結
果を表３に示す。EXAMPLES Steel materials having various chemical compositions shown in Table 2 (A to
H) 100 kg of each is melted in a vacuum melting furnace, then 15
Forged into a 0 mm square. Then, after hot rolling to finish the bar-in coil of 20mmφ, wind it at 800 ℃, and then
It was cooled to 600 ° C at a rate of 100 ° C / h. Note that some of them were air-cooled for comparison. A of the obtained steel materials
Table 3 shows the results of examining the mechanical properties of the ~ E steels after rolling.
【００２９】[0029]
【表２】 [Table 2]
【００３０】[0030]
【表３】 [Table 3]
【００３１】表３より明らかなように、Moを含まない場
合( 比較鋼Ａ) には空冷でも十分に軟化しているが、Cr
やMoの含有量が増す（比較鋼Ｂ, C1, Ｄ, E1）とベイナ
イト組織となり、強度が高く、延性が低下している。こ
れに対し、本発明鋼のＣ、Ｄ及びＥはいずれも、比較鋼
Ａには及ばないものの十分に軟化し、伸線加工やボルト
成形には何ら支障はない。As is clear from Table 3, when Mo is not contained (Comparative Steel A), it is sufficiently softened even by air cooling, but Cr
When the content of Al and Mo increases (comparative steels B, C1, D, E1), a bainite structure is formed, the strength is high and the ductility is reduced. On the other hand, C, D, and E of the steels of the present invention are not as high as those of the comparative steel A, but are sufficiently softened, and there is no problem in wire drawing or bolt forming.
【００３２】ついで、これらの鋼材につき、ベイナイト
組織を呈する比較鋼は745℃で球状化焼鈍を行い、その
後調質した。また本発明鋼は圧延まま材を調質した。こ
こに焼き入れ温度は 880℃とし、また焼き戻し温度はそ
れぞれの組成によって変更して、いずれの鋼もＦ10Ｔク
ラスの強度約110kgf/mm2が得られるように調整した。得
られた調質材からJIS ４号シャルピー試片（２mmＶノッ
チ）を加工し、衝撃試験（20℃）を行った。その結果を
表４に示す。Next, of these steel materials, comparative steels having a bainite structure were subjected to spheroidizing annealing at 745 ° C. and then tempered. Further, the steel of the present invention was heat-treated as it was rolled. The quenching temperature was set to 880 ° C., and the tempering temperature was changed according to each composition, and each steel was adjusted so as to obtain strength of about 110 kgf / mm 2 of F10T class. A JIS No. 4 Charpy test piece (2 mm V notch) was processed from the obtained heat treated material, and an impact test (20 ° C.) was performed. The results are shown in Table 4.
【００３３】[0033]
【表４】 [Table 4]
【００３４】同表より明らかなように、比較鋼及び本発
明鋼共に引っ張り試験値に大差は認められないものの、
衝撃値は本発明鋼は約20kgm/cm2以上と高く、比較鋼に
比べ極めて高い靭性が得られている。この理由は、比較
鋼の場合、球状化焼鈍によって生成した炭化物が調質時
に未溶解となり一部残存するためである。この結果は焼
き入れ温度を通常の温度よりも30〜40℃上昇させても衝
撃値は２〜３kgm/cm2 改善される程度である。さらに、
上昇あるいは長時間保持させるのは実用炉への適用は困
難となり、脱炭層も生成し易くなり、好ましくない。As is clear from the table, although there is no great difference in the tensile test values between the comparative steel and the steel of the present invention,
The impact value of the steel of the present invention is as high as about 20 kgm / cm 2 or more, and extremely high toughness is obtained as compared with the comparative steel. The reason for this is that in the case of the comparative steel, the carbide produced by the spheroidizing annealing becomes unmelted during refining and remains partially. The result is that the impact value is improved by 2 to 3 kgm / cm 2 even when the quenching temperature is increased by 30 to 40 ° C. above the normal temperature. further,
It is not preferable to raise or hold for a long time because it is difficult to apply to a practical furnace and a decarburized layer is easily formed.
【００３５】次に、これらの鋼材の 600℃での高温引っ
張り試験結果を表５に示す。Next, Table 5 shows the results of the high temperature tensile test of these steel materials at 600 ° C.
【表５】 [Table 5]
【００３６】同表より明らかなように、 600℃における
耐力は比較鋼では20kgf/mm2 以下程度にすぎなかったの
に対し、本発明鋼はいずれも38kgf/mm2 以上と十分に高
い値を示した。また、比較鋼の強度は40kgf/mm2 以下と
低くかったのに対し、本発明鋼の強度はは約50kgf/mm2
以上と高く、高温領域において十分な耐力、強度を有し
ていた。As is clear from the table, the yield strength at 600 ° C. was only 20 kgf / mm 2 or less for the comparative steels, whereas the invention steels all had a sufficiently high value of 38 kgf / mm 2 or more. Indicated. Further, the strength of the comparative steel was as low as 40 kgf / mm 2 or less, whereas the strength of the steel of the present invention was about 50 kgf / mm 2
It was high as above and had sufficient yield strength and strength in the high temperature region.
【００３７】次に、前掲表１に示す鋼Ａ〜Ｈを用いてＭ
20ボルト及びナットを製造し、その実体試験を行った。
なお、比較鋼及び本発明鋼のＣ，Ｅ，Ｆ及びＨはＦ10Ｔ
クラスの強度、一方、本発明鋼のＤ及びＧは、JIS12.9
ボルトに規定される高強度を狙い、引っ張り強さは130k
gf/mm2に設計した。これらのボルトの引っ張り試験値、
衝撃値及び 600℃の耐力について調べた結果を表６に示
す。Next, using steels A to H shown in Table 1 above, M
Twenty bolts and nuts were manufactured and a substantial test was conducted.
C, E, F and H of the comparative steel and the steel of the present invention are F10T.
Class strength, while D and G of the steel of the present invention are JIS 12.9
Aiming at the high strength specified for bolts, the tensile strength is 130k
Designed to gf / mm 2 . Tensile test values for these bolts,
Table 6 shows the results of the examination of impact value and proof stress at 600 ° C.
【００３８】[0038]
【表６】 [Table 6]
【００３９】同表より明らかなように、本発明鋼を用い
たボルトの性質は 高温において十分な耐力を有し、か
つ靱性が高く、特に130kgf/mm2級の高強度域においても
十分な靭性を有していた。またナットについても、その
硬さは JIS範囲を十分に満足するものであった。As is clear from the table, the properties of the bolt using the steel of the present invention have sufficient proof stress at high temperature and high toughness, especially in the high strength region of 130 kgf / mm 2 class. Had. In addition, the hardness of the nut was sufficiently within the JIS range.
【００４０】[0040]
【発明の効果】かくして本発明によれば、常温特性のみ
ならず高温特性が極めて優れた耐熱性高強度ボルトを得
ることができ、とくに各種の耐熱構造用鋼の締結ボルト
に利用して有用である。また本発明によれば、従来不可
欠とされた球状化焼鈍を必要としないので、従来法に比
較して省工程、低コストを実現することができ、産業上
の有用性は極めて高い。As described above, according to the present invention, it is possible to obtain a heat-resistant high-strength bolt having extremely excellent high-temperature characteristics as well as normal-temperature characteristics, which is particularly useful as a fastening bolt for various heat-resistant structural steels. is there. Further, according to the present invention, since spheroidizing annealing, which has been indispensable in the past, is not required, the number of steps and the cost can be reduced as compared with the conventional method, and the industrial utility is extremely high.
【図１】中炭素−Cr鋼にMoを添加したときの、Mo含有量
と高温引っ張り特性との関係を示したグラフである。FIG. 1 is a graph showing the relationship between Mo content and high temperature tensile properties when Mo is added to medium carbon-Cr steel.
Claims (2)
熱間圧延後, 巻き取り温度から 600℃までを 200℃／ｈ
以下の速度で冷却し、ついで伸線加工後、ボルト成形加
工を施したのち、焼き入れ−焼き戻し処理を施すことを
特徴とする靭性の高い耐熱性高強度ボルトの製造方法。1. C: 0.15-0.40 wt%, Si: 0.5 wt% or less, Mn: 0.30-1.50 wt%, Cr: 0.30-1.50 wt%, Mo: 0.30-0.70 wt%, Ti: 0.005-0.050 wt. %, Al: 0.005-0.050 wt% and B: 0.0005-0.0030 wt%, the balance being a steel material consisting of Fe and inevitable impurities,
After hot rolling, take-up temperature from 600 ℃ up to 200 ℃ / h
A method for producing a heat-resistant high-strength bolt having high toughness, which comprises cooling at a rate below, followed by wire drawing, bolt forming, and quenching-tempering.
成に加え、 Ｖ：0.03〜0.20wt％、 Nb：0.005 〜0.04wt％及び Ni：0.10〜0.50wt％ のうちから選んだ１種又は２種以上を含む組成になるも
のである耐熱性高強度ボルトの製造方法。2. The steel material according to claim 1, wherein, in addition to the above steel composition, one selected from V: 0.03 to 0.20 wt%, Nb: 0.005 to 0.04 wt% and Ni: 0.10 to 0.50 wt%. Alternatively, a method for producing a heat-resistant high-strength bolt having a composition containing two or more kinds.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27095791A JP3160329B2 (en) | 1991-10-18 | 1991-10-18 | Manufacturing method of heat resistant high strength bolt |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27095791A JP3160329B2 (en) | 1991-10-18 | 1991-10-18 | Manufacturing method of heat resistant high strength bolt |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05105957A true JPH05105957A (en) | 1993-04-27 |
| JP3160329B2 JP3160329B2 (en) | 2001-04-25 |
Family
ID=17493380
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP27095791A Expired - Fee Related JP3160329B2 (en) | 1991-10-18 | 1991-10-18 | Manufacturing method of heat resistant high strength bolt |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3160329B2 (en) |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100263426B1 (en) * | 1998-02-20 | 2000-08-01 | 윤영석 | Large moulding sreel having constant hardness |
| WO2001079567A1 (en) * | 2000-04-07 | 2001-10-25 | Kabushiki Kaisha Kobe Seiko Sho | Method for manufacturing high strength bolt excellent in resistance to delayed fracture and to relaxation |
| KR20020047667A (en) * | 2000-12-13 | 2002-06-22 | 이계안 | Method of making a stud bolt for a ball joint |
| KR20020084590A (en) * | 2001-05-03 | 2002-11-09 | 현대자동차주식회사 | Method for an automotive cylinder head bolt |
| FR2916371A1 (en) * | 2007-05-24 | 2008-11-28 | Fwu Kuang Entpr Co Ltd | Preparing forged parts having a tensile strength and high elongation, comprises forming forged parts from a wire rod, heating forged parts up to a temperature of specified range, and subjecting forged parts to first and second tempering |
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| CN106555036A (en) * | 2016-12-07 | 2017-04-05 | 河池市技术开发中心 | A kind of bolt Technology for Heating Processing |
| CN110468328A (en) * | 2019-08-05 | 2019-11-19 | 洛阳双瑞特种装备有限公司 | A kind of steel structure bolt steel |
| CN114592156A (en) * | 2022-03-09 | 2022-06-07 | 广东一诺重工钢构有限公司 | High-strength steel beam and processing technology thereof |
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Families Citing this family (1)
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| CN104561822B (en) * | 2014-12-17 | 2016-06-22 | 秦皇岛首秦金属材料有限公司 | A kind of high-strength tenacity spy's thick low-alloy quenched and tempered steel and preparation method thereof |
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Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100263426B1 (en) * | 1998-02-20 | 2000-08-01 | 윤영석 | Large moulding sreel having constant hardness |
| WO2001079567A1 (en) * | 2000-04-07 | 2001-10-25 | Kabushiki Kaisha Kobe Seiko Sho | Method for manufacturing high strength bolt excellent in resistance to delayed fracture and to relaxation |
| US6605166B2 (en) | 2000-04-07 | 2003-08-12 | Kabushiki Kaisha Kobe Seiko Sho | Method for manufacturing high strength bolt excellent in resistance to delayed fracture and to relaxation |
| KR20020047667A (en) * | 2000-12-13 | 2002-06-22 | 이계안 | Method of making a stud bolt for a ball joint |
| KR20020084590A (en) * | 2001-05-03 | 2002-11-09 | 현대자동차주식회사 | Method for an automotive cylinder head bolt |
| FR2916371A1 (en) * | 2007-05-24 | 2008-11-28 | Fwu Kuang Entpr Co Ltd | Preparing forged parts having a tensile strength and high elongation, comprises forming forged parts from a wire rod, heating forged parts up to a temperature of specified range, and subjecting forged parts to first and second tempering |
| CN103469107A (en) * | 2013-09-18 | 2013-12-25 | 济钢集团有限公司 | A517Gr.B large pressure steel plate with low cost and high toughness and production method thereof |
| CN106555036A (en) * | 2016-12-07 | 2017-04-05 | 河池市技术开发中心 | A kind of bolt Technology for Heating Processing |
| CN110468328A (en) * | 2019-08-05 | 2019-11-19 | 洛阳双瑞特种装备有限公司 | A kind of steel structure bolt steel |
| CN110468328B (en) * | 2019-08-05 | 2021-03-23 | 洛阳双瑞特种装备有限公司 | Steel for steel structure bolt |
| CN114592156A (en) * | 2022-03-09 | 2022-06-07 | 广东一诺重工钢构有限公司 | High-strength steel beam and processing technology thereof |
| CN114592156B (en) * | 2022-03-09 | 2023-08-18 | 广东一诺重工钢构有限公司 | High-strength steel beam and processing technology thereof |
| CN116024499A (en) * | 2022-12-28 | 2023-04-28 | 燕山大学 | Steel for 10.9-grade bolt resistant to hydrogen-induced delayed fracture and preparation method of 10.9-grade bolt |
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