JPH08177831A - High strength bolt which excels in delayed fracture resistance characteristic - Google Patents

High strength bolt which excels in delayed fracture resistance characteristic

Info

Publication number
JPH08177831A
JPH08177831A JP32331594A JP32331594A JPH08177831A JP H08177831 A JPH08177831 A JP H08177831A JP 32331594 A JP32331594 A JP 32331594A JP 32331594 A JP32331594 A JP 32331594A JP H08177831 A JPH08177831 A JP H08177831A
Authority
JP
Japan
Prior art keywords
delayed fracture
fracture resistance
strength
bolt
strength bolt
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP32331594A
Other languages
Japanese (ja)
Inventor
Nobuyuki Ishikawa
信行 石川
Tetsuo Shiragami
哲夫 白神
Akira Ehata
明 江畑
Moriyuki Ishiguro
守幸 石黒
Tetsuyuki Ishizaki
哲行 石崎
Masao Kamei
正雄 亀井
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
MITSUBOSHI IND
JFE Engineering Corp
Mitsuboshi Sangyo Co Ltd
Original Assignee
MITSUBOSHI IND
NKK Corp
Nippon Kokan Ltd
Mitsuboshi Sangyo Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by MITSUBOSHI IND, NKK Corp, Nippon Kokan Ltd, Mitsuboshi Sangyo Co Ltd filed Critical MITSUBOSHI IND
Priority to JP32331594A priority Critical patent/JPH08177831A/en
Publication of JPH08177831A publication Critical patent/JPH08177831A/en
Pending legal-status Critical Current

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  • Connection Of Plates (AREA)

Abstract

PURPOSE: To provide a high strength bolt which has the strength of not less than a specific value and at the same time excels in a delayed fracture resistance characteristic. CONSTITUTION: This high strength bolt has the tensile strength of not less than 1300N/m<2> and excels in a delayed fracture resistance characteristic and has an asymmetrical thread form in which the left and right flanks of a thread are different, and the flank angle of a pressure side flank surface 2a is 40 to 60 deg..

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【産業上の利用分野】本発明は、建築、土木分野におけ
る各種構造物に用いる摩擦接合用の高力ボルトに関し、
1300N/mm2 以上の引張強度を有する耐遅れ破壊
特性に優れた高力ボルトに関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-strength bolt for friction welding used in various structures in the fields of construction and civil engineering,
The present invention relates to a high strength bolt having a tensile strength of 1300 N / mm 2 or more and excellent in delayed fracture resistance.

【0002】[0002]

【従来の技術】高力ボルトは、橋梁、建築物、自動車、
機械等に多く使用されているが、引張強度が1250N
/mm2 を超えると遅れ破壊が生じやすくなることか
ら、JIS・B1186や、JIS・B1051では、
それぞれF10T級、12.9級が上限の強度と規定さ
れている。
2. Description of the Related Art High-strength bolts are used for bridges, buildings, automobiles,
It is widely used in machinery, but has a tensile strength of 1250N.
If it exceeds / mm 2 , delayed fracture is likely to occur. Therefore, according to JIS / B1186 and JIS / B1051,
F10T grade and 12.9 grade are respectively defined as the upper limit strength.

【0003】しかし、どの分野においても高強度化のニ
ーズが強く、高力ボルトの耐遅れ破壊特性の改善が強く
望まれている。高力ボルトの遅れ破壊は、応力集中が生
じやすいねじ谷部から発生することが多いことから、通
常の三角ねじにおいてねじ谷のRをおおきくし、応力集
中係数を小さくすることにより耐遅れ破壊特性が向上す
ることが一般的に知られている。また、特開平4−29
607号公報には、ねじ谷形状を長軸がボルトの軸方向
と平行な楕円の円弧とた高力ボルトが開示されている。
However, in every field, there is a strong need for higher strength, and improvement in delayed fracture resistance of high strength bolts is strongly desired. Delayed fracture of high-strength bolts often occurs from thread troughs where stress concentration is likely to occur. Therefore, in normal triangular threads, the radius R of the thread trough is set to be large and the stress concentration coefficient is reduced to make delayed fracture resistance Is generally known to improve. In addition, JP-A-4-29
Japanese Patent No. 607 discloses a high-strength bolt having a thread trough having an elliptic arc whose major axis is parallel to the axial direction of the bolt.

【0004】[0004]

【発明が解決しようとする課題】しかしながら、通常の
三角ねじにおいてねじ底Rの変更により応力集中係数を
低減するだけでは、ボルトの高強度化に伴う遅れ破壊感
受性の低下を補うことはできず、1300N/mm2
上では遅れ破壊を生じてしまう。
However, it is not possible to compensate for the decrease in delayed fracture susceptibility associated with the increase in strength of bolts only by reducing the stress concentration factor by changing the screw bottom R in a normal triangular screw. If it is 1300 N / mm 2 or more, delayed fracture will occur.

【0005】また、特開平4−29607号公報に開示
された高力ボルトは、応力集中がさらに軽減されるが、
耐遅れ破壊特性ついての実験例は一切示されておらず、
1300N/mm2 以上の強度では実際に使用した場合
に遅れ破壊を起こす可能性がある。
In the high-strength bolt disclosed in Japanese Patent Laid-Open No. 4-29607, stress concentration is further reduced,
No experimental example is shown for delayed fracture resistance,
If the strength is 1300 N / mm 2 or more, delayed fracture may occur in actual use.

【0006】本発明は、かかる事情に鑑みてなされたも
のであって、1300N/mm2 以上の強度を有しなが
ら耐遅れ破壊特性に優れた高力ボルトを提供することを
目的とする。
The present invention has been made in view of the above circumstances, and an object thereof is to provide a high-strength bolt having a strength of 1300 N / mm 2 or more and excellent in delayed fracture resistance.

【0007】[0007]

【課題を解決するための手段】本発明者らは、高力ボル
トの耐遅れ破壊特性とねじ形状との関係について鋭意研
究を重ねた結果、1300N/mm2 以上の高強度にお
いてはボルトのねじ形状非対称とすることで耐遅れ破壊
特性を大幅に向上することができることを見出した。
DISCLOSURE OF THE INVENTION The inventors of the present invention have conducted extensive studies on the relationship between the delayed fracture resistance of high strength bolts and the screw shape, and as a result, at high strengths of 1300 N / mm 2 or higher, bolt threads It was found that the delayed fracture resistance can be significantly improved by making the shape asymmetric.

【0008】本発明はこのような知見に基づいてなされ
たものであって、ねじ山の左右フランクが異なる非対称
のねじ形状を有するボルトであって、圧力側フランク面
のフランク角が40〜60°であり、引張強度が130
0N/mm2 以上であることを特徴とする耐遅れ破壊特
性に優れた高力ボルトを提供する。
The present invention has been made on the basis of such knowledge, and is a bolt having an asymmetrical thread shape in which the left and right flanks of the thread are different, and the flank angle of the pressure side flank surface is 40 to 60 °. And the tensile strength is 130
A high-strength bolt excellent in delayed fracture resistance, which is characterized by being 0 N / mm 2 or more.

【0009】[0009]

【作用】図1は本発明に係る高力ボルトのねじ形状を模
式的に示す図である。図1において、参照符号1a,1
bはとがり山であり、2aは圧力側フランク面、2bは
遊び側フランク面、3は谷底、αはねじ山の角度、α1
は圧力側フランク面のフランク角、α2は遊び側フラン
ク面のフランク角である。
1 is a diagram schematically showing the thread shape of the high-strength bolt according to the present invention. In FIG. 1, reference numerals 1a, 1
b is a point, 2a is a flank on the pressure side, 2b is a flank on the idle side, 3 is the bottom of the valley, α is the angle of the thread, α1
Is the flank angle of the pressure side flank surface, and α2 is the flank angle of the play side flank surface.

【0010】この図に示すように、本発明の高力ボルト
は、圧力側フランク面2aのフランク角α1と、遊び側
フランク面2bのフランク角2αの大きさが異なる非対
称のねじ形状を有しており、かつ圧力側のフランク角が
40〜60°である。
As shown in this figure, the high-strength bolt of the present invention has an asymmetrical screw shape in which the flank angle α1 of the pressure side flank surface 2a and the flank angle 2α of the play side flank surface 2b are different. And the flank angle on the pressure side is 40 to 60 °.

【0011】本発明においてねじ形状を非対称としかつ
圧力側のフランク角を40〜60°とする理由は以下の
通りである。すなわち、圧力側フランク面はボルト締結
時に直接荷重が加わる部分であるが、この面のフランク
角が大きいほど、耐遅れ破壊特性が向上する。従って、
圧力側フランク角が大きい非対称のねじ形状とする。こ
の場合に、圧力側フランク角の角度が40°未満では耐
遅れ破壊特性が不十分であり、60°を超えるとボルト
締結時にナット抜けを生じるので、圧力側のフランク角
の大きさを40〜60°の範囲に規定したのである。
The reason why the screw shape is asymmetric and the flank angle on the pressure side is 40 to 60 ° in the present invention is as follows. That is, the pressure-side flank surface is a portion to which a load is directly applied at the time of bolt fastening, and the larger the flank angle of this surface is, the more the delayed fracture resistance is improved. Therefore,
Use an asymmetrical screw shape with a large flank angle on the pressure side. In this case, if the pressure side flank angle is less than 40 °, the delayed fracture resistance is insufficient, and if it exceeds 60 °, the nut may come off during bolt fastening. It is defined in the range of 60 °.

【0012】本発明において、遊び側フランク面のフラ
ンク角α2の大きさは、耐遅れ破壊特性に対しては影響
しないため、その大きさは特に規定していないが、ねじ
山の屈曲およびナットぬけを防止するため、遊び側フラ
ンク面のフランク角を10〜20°とし、ねじ山の角度
αを50〜70°とすることが望ましい。
In the present invention, the size of the flank angle α2 of the play-side flank surface does not affect the delayed fracture resistance, so its size is not specified, but the bending of the thread and the nut slippage are not specified. In order to prevent this, it is desirable that the flank angle of the play side flank surface is 10 to 20 ° and the angle α of the screw thread is 50 to 70 °.

【0013】図2はねじ形状が左右対称、すなわち圧力
側フランク角α1と遊び側フランク角α2の大きさが同
じ従来のボルトを示すものであるが、この場合には、望
ましいねじ山角度αの範囲50〜70°において、圧力
側フランク角α1を最大でも35°にしかできず、耐遅
れ破壊特性が不十分である。
FIG. 2 shows a conventional bolt having a symmetrical screw shape, that is, the pressure side flank angle α1 and the idle side flank angle α2 have the same magnitude. In this case, the desired thread angle α is In the range of 50 to 70 °, the flank angle α1 on the pressure side can be only 35 ° at the maximum, and the delayed fracture resistance is insufficient.

【0014】[0014]

【実施例】以下、本発明の実施例について説明する。こ
の実施例における供試鋼の組成を表1に示す。表1にお
いてIはJIS・SCM435に規定された鋼であり、
IIはP,Sを低減し、かつNi,Tiを添加した耐遅れ
破壊特性改善鋼である。これらの供試鋼を用いて、22
mmφの丸棒に圧延し、焼鈍後に冷間鍛造によりM22
のボルトに形成し、焼入れ焼もどしにより、引張強度を
Iで1360N/mm2 、IIで1430N/mm2 とし
た。
Embodiments of the present invention will be described below. Table 1 shows the composition of the sample steel in this example. In Table 1, I is steel specified in JIS SCM435,
II is a steel with improved delayed fracture resistance containing reduced P and S and added with Ni and Ti. Using these test steels, 22
M22 by rolling into a mmφ round bar and annealing after cold forging
Is formed on the bolt, by tempering even Quenched, the tensile strength was at 1360N / mm 2, II and 1430N / mm 2 at I.

【0015】ボルトのねじ形状としては、図1に示す非
対称ねじ、および図2に示す三角ねじを用い、その詳細
寸法を表2に示した。これらの図において参照符号1
a,1b,2a,2b,3,αは前述した通りであり、
その他r1,r2は谷底の曲率半径、Hはとがり山の高
さ、pはピッチを示す。
As the screw shape of the bolt, the asymmetric screw shown in FIG. 1 and the triangular screw shown in FIG. 2 were used, and the detailed dimensions thereof are shown in Table 2. In these figures, reference numeral 1
a, 1b, 2a, 2b, 3, α are as described above,
In addition, r1 and r2 indicate the radius of curvature of the valley bottom, H indicates the height of the sharp peak, and p indicates the pitch.

【0016】[0016]

【表1】 [Table 1]

【0017】[0017]

【表2】 [Table 2]

【0018】このようなねじが形成されたボルトに対し
て遅れ破壊試験を行った。遅れ破壊試験では、各ボルト
10本ずつ鋼板にナット回転角法にて締付け、3.5%
食塩水で乾湿繰り返しの試験を6ケ月間実施し、破断の
有無を調べた。その結果を表3に示す。
A delayed fracture test was performed on a bolt having such a screw formed therein. In the delayed fracture test, tighten 10 bolts on each steel plate by the nut rotation angle method, 3.5%
A test of repeated dry and wet with a saline solution was carried out for 6 months to examine the presence or absence of breakage. Table 3 shows the results.

【0019】[0019]

【表3】 [Table 3]

【0020】表3に示すように、本発明のねじ形状を有
するA,B,Cのボルトは、いずれも遅れ破壊を生じな
かった。これに対して、Dは非対称のねじ形状を有して
はいるが、圧力側フランク角が小さいため遅れ破壊を生
じた。また、Eは従来の三角ねじであり、遅れ破壊が生
じている。Fは従来の三角ねじにおいて、ねじ底の丸み
をEよりも大きくしたものであるが、やはり遅れ破壊が
生じた。従って、このような手段を講じても、1300
N/mm2 以上の強度では遅れ破壊を防止し得ないこと
が確認された。
As shown in Table 3, none of the bolts A, B and C having the screw shape of the present invention caused delayed fracture. On the other hand, although D has an asymmetrical screw shape, delayed fracture occurred because the flank angle on the pressure side was small. Further, E is a conventional triangular screw, and delayed fracture has occurred. F is a conventional triangular screw whose roundness of the screw bottom is larger than that of E, but delayed fracture also occurred. Therefore, even if such measures are taken, 1300
It was confirmed that delayed fracture cannot be prevented with a strength of N / mm 2 or more.

【0021】以上のように、本発明で規定するねじ形状
とすることにより、従来鋼であるSCM435鋼でも耐
遅れ破壊特性に優れた1300N/mm2 級の高力ボル
トが得られ、耐遅れ破壊特性改善鋼では1400N/m
2 級以上の強度を有し耐遅れ破壊特性に優れた高力ボ
ルトを得られることが確認された。
As described above, by adopting the thread shape defined by the present invention, a high strength bolt of 1300 N / mm 2 class having excellent delayed fracture resistance can be obtained even with the conventional steel SCM435 steel, and delayed fracture resistance is obtained. 1400 N / m for property-improving steel
It was confirmed that a high-strength bolt having a strength of m 2 class or higher and excellent in delayed fracture resistance can be obtained.

【0022】[0022]

【発明の効果】以上説明したように、本発明によれば、
1300N/mm2 以上の強度を有しながら耐遅れ破壊
特性に優れた高力ボルトを得ることができ、産業上極め
て大きな意義を有する。
As described above, according to the present invention,
It is possible to obtain a high-strength bolt excellent in delayed fracture resistance while having a strength of 1300 N / mm 2 or more, which has an extremely great industrial significance.

【図面の簡単な説明】[Brief description of drawings]

【図1】本発明に係る高力ボルトに適用される非対称ね
じのねじ形状を示す図。
FIG. 1 is a diagram showing a screw shape of an asymmetric screw applied to a high-strength bolt according to the present invention.

【図2】従来の高力ボルトに適用される三角ねじのねじ
形状を示す図。
FIG. 2 is a view showing a screw shape of a triangular screw applied to a conventional high strength bolt.

【符号の説明】[Explanation of symbols]

1a,1b……とがり山、2a……圧力側フランク面、
2b……遊び側フランク面、3……谷底、α……ねじ山
の角度、α1……圧力側フランク面のフランク角、α2
……遊び側フランク面のフランク角、H……とがり山の
高さ、p……ピッチ
1a, 1b ... pointed ridges, 2a ... pressure side flank surface,
2b: Play-side flank surface, 3 ... Valley bottom, α: Thread angle, α1: Pressure-side flank angle, α2
…… Frank angle of the flank on the play side, H …… Height of the point, p …… Pitch

───────────────────────────────────────────────────── フロントページの続き (72)発明者 江畑 明 東京都千代田区丸の内一丁目1番2号日本 鋼管株式会社内 (72)発明者 石黒 守幸 東京都千代田区丸の内一丁目1番2号日本 鋼管株式会社内 (72)発明者 石崎 哲行 東京都千代田区丸の内一丁目1番2号日本 鋼管株式会社内 (72)発明者 亀井 正雄 大阪府大阪市住之江区緑木一丁目4番16号 三星産業株式会社大阪工場内 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Akira Ebata Akira Marunouchi 1-2-2 Japan, Chiyoda-ku, Tokyo Japan Steel Pipe Co., Ltd. (72) Moriyuki Ishiguro 1-2-1 Marunouchi Chiyoda-ku, Tokyo Japan Steel Pipe Co., Ltd. (72) Inventor Tetsuyuki Ishizaki 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan Steel Pipe Co., Ltd. (72) Masao Kamei, 4-16 Midoriki, Suminoe-ku, Osaka, Osaka Prefecture Samsung Sangyo Osaka Factory Co., Ltd.

Claims (1)

【特許請求の範囲】[Claims] 【請求項1】 ねじ山の左右フランクが異なる非対称の
ねじ形状を有するボルトであって、圧力側フランク面の
フランク角が40〜60°であり、引張強度が1300
N/mm2 以上であることを特徴とする耐遅れ破壊特性
に優れた高力ボルト。
1. A bolt having an asymmetrical thread shape in which left and right flanks of a screw thread are different, wherein a flank angle of a pressure side flank is 40 to 60 °, and a tensile strength is 1300.
High-strength bolt with excellent delayed fracture resistance characterized by N / mm 2 or more.
JP32331594A 1994-12-26 1994-12-26 High strength bolt which excels in delayed fracture resistance characteristic Pending JPH08177831A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP32331594A JPH08177831A (en) 1994-12-26 1994-12-26 High strength bolt which excels in delayed fracture resistance characteristic

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP32331594A JPH08177831A (en) 1994-12-26 1994-12-26 High strength bolt which excels in delayed fracture resistance characteristic

Publications (1)

Publication Number Publication Date
JPH08177831A true JPH08177831A (en) 1996-07-12

Family

ID=18153422

Family Applications (1)

Application Number Title Priority Date Filing Date
JP32331594A Pending JPH08177831A (en) 1994-12-26 1994-12-26 High strength bolt which excels in delayed fracture resistance characteristic

Country Status (1)

Country Link
JP (1) JPH08177831A (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003014584A1 (en) * 2001-08-07 2003-02-20 Nobuyuki Sugimura Inverse saw-tooth internal thread
WO2004048785A1 (en) * 2002-11-22 2004-06-10 Nippon Accumulator Co., Ltd. Accumulator using internal and external threads
US7753631B2 (en) * 2003-04-30 2010-07-13 Nobuyuki Sugimura Pitch diameter displaced screw
JP2013139872A (en) * 2011-12-09 2013-07-18 National Institute For Materials Science High tensile bolt and method for manufacturing the same
WO2013146882A1 (en) 2012-03-29 2013-10-03 日立ツール株式会社 Machining head, holder and exchangeable tip cutting tool
CN104033462A (en) * 2014-06-10 2014-09-10 福建海源自动化机械股份有限公司 Prestressed threaded pull rod device as well as production method and application thereof
WO2019192551A1 (en) * 2018-04-07 2019-10-10 玉环胜友工具有限公司 Connection structure of bolt and nut with olive-shaped bidirectional conical thread having small left taper and large right taper

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003014584A1 (en) * 2001-08-07 2003-02-20 Nobuyuki Sugimura Inverse saw-tooth internal thread
WO2004048785A1 (en) * 2002-11-22 2004-06-10 Nippon Accumulator Co., Ltd. Accumulator using internal and external threads
EP1564413A1 (en) * 2002-11-22 2005-08-17 Nobuyuki Sugimura Accumulator using internal and external threads
EP1564413A4 (en) * 2002-11-22 2006-02-08 Nobuyuki Sugimura Accumulator using internal and external threads
US7753631B2 (en) * 2003-04-30 2010-07-13 Nobuyuki Sugimura Pitch diameter displaced screw
JP2013139872A (en) * 2011-12-09 2013-07-18 National Institute For Materials Science High tensile bolt and method for manufacturing the same
WO2013146882A1 (en) 2012-03-29 2013-10-03 日立ツール株式会社 Machining head, holder and exchangeable tip cutting tool
EP2832481A4 (en) * 2012-03-29 2015-08-12 Hitachi Tool Eng Machining head, holder and exchangeable tip cutting tool
US9868162B2 (en) 2012-03-29 2018-01-16 Hitachi Tool Engineering, Ltd. Machining head, holder and exchangeable tip cutting tool
CN104033462A (en) * 2014-06-10 2014-09-10 福建海源自动化机械股份有限公司 Prestressed threaded pull rod device as well as production method and application thereof
WO2019192551A1 (en) * 2018-04-07 2019-10-10 玉环胜友工具有限公司 Connection structure of bolt and nut with olive-shaped bidirectional conical thread having small left taper and large right taper

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