JPH07103871A - Method for evaluating fatigue fracture sensibility at part subjected to welding heat - Google Patents
Method for evaluating fatigue fracture sensibility at part subjected to welding heatInfo
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- JPH07103871A JPH07103871A JP27117793A JP27117793A JPH07103871A JP H07103871 A JPH07103871 A JP H07103871A JP 27117793 A JP27117793 A JP 27117793A JP 27117793 A JP27117793 A JP 27117793A JP H07103871 A JPH07103871 A JP H07103871A
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- fatigue
- test piece
- fatigue fracture
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は造船、海洋構造物、橋
梁、建設機械などの溶接部材に発生する疲労破壊を再現
し、鋼材の溶接熱影響部における疲労破壊に対する感受
性を簡易に評価する試験法に関するものである。BACKGROUND OF THE INVENTION The present invention reproduces fatigue fracture occurring in welded members such as shipbuilding, offshore structures, bridges, and construction machinery, and easily evaluates the susceptibility of steel materials to fatigue fracture in the heat affected zone. It is about law.
【０００２】[0002]
【従来の技術】溶接鋼構造物において設計上考慮すべき
最も重要な破壊形態は繰り返し荷重によって生じる疲労
破壊である。たとえば、海洋構造物においては１９８０
年にアレキサンダーキーランド号が疲労き裂を起点とし
た破壊により転覆事故を起こしている。また、１９９０
年代に建造された大型石油輸送タンカーにおいては疲労
き裂が発見され、原油漏れの危険性が指摘された。この
ような溶接鋼構造物における疲労き裂のほとんどは溶接
部から発生している。溶接部の疲労強度向上は溶接構造
物の安全性確保のために喫緊の課題である。2. Description of the Related Art In welded steel structures, the most important failure mode to be considered in design is fatigue failure caused by repeated loading. For example, in offshore structures 1980
In the year Alexander Keyland caused a capsize accident due to a fracture starting from a fatigue crack. Also, 1990
Fatigue cracks were found in a large oil transport tanker constructed in the 1980s, and the risk of a crude oil leak was pointed out. Most of the fatigue cracks in such welded steel structures originate from the weld. Improving the fatigue strength of welds is an urgent issue for ensuring the safety of welded structures.
【０００３】溶接部の疲労強度は母材部のそれと比較し
て著しく低下することはよく知られた事実であり、たと
えば、Ｔ．Ｒ．ガーニィ著「溶接構造の疲れ」（産報出
版、１９７３年）では溶接部の疲労破壊を支配する要因
について述べられている。これによると溶接部の疲労強
度は応力集中、溶接部組織など種々の要因に支配され、
溶接部疲労強度は母材部の疲労強度より著しく低下す
る。また、母材と溶接部では疲労強度支配要因が異な
る。このために、溶接部の疲労強度を評価するためには
実溶接継手を作成し、この継手から疲労試験片を加工
し、疲労試験に供する必要がある。一般に、溶接継手疲
労試験片は大型であり、このために大型の疲労試験機を
使用する必要がある。また、負荷荷重が高くなるため
に、繰り返し荷重の周波数を高くすることは困難であ
る。従って、溶接部の疲労強度を得るためには多大の時
間を要することになる。It is a well known fact that the fatigue strength of a welded part is significantly reduced as compared with that of a base metal part. R. Gurney's "Fatigue of Welded Structures" (Industrial Publication, 1973) describes the factors that govern fatigue fracture of welds. According to this, the fatigue strength of welds is governed by various factors such as stress concentration and weld microstructure,
The fatigue strength of welds is significantly lower than that of the base metal. In addition, the factors that govern fatigue strength differ between the base metal and the weld. Therefore, in order to evaluate the fatigue strength of the welded portion, it is necessary to prepare an actual welded joint, process a fatigue test piece from this joint, and subject it to a fatigue test. Generally, welded joint fatigue test pieces are large, which requires the use of large fatigue testers. Further, since the applied load becomes high, it is difficult to increase the frequency of the repeated load. Therefore, it takes a lot of time to obtain the fatigue strength of the welded portion.
【０００４】さらに、溶接部の疲労強度は応力集中の原
因となる溶接止端部形状の影響を受けることはよく知ら
れた事実であるが、実溶接継手においては溶接条件の変
動により止端部形状が微妙に変動し、このために溶接部
の疲労強度は母材の疲労強度に比べてばらつきが大き
い。従って、実溶接継手の疲労試験を行う限り、鋼材の
化学成分、溶接条件などの影響因子を抽出して定量的に
評価することが困難である場合が多い。Further, it is a well known fact that the fatigue strength of a welded portion is affected by the shape of the weld toe portion which causes stress concentration. The shape slightly changes, and therefore the fatigue strength of the welded portion varies more than the fatigue strength of the base metal. Therefore, as long as the fatigue test of the actual welded joint is performed, it is often difficult to extract and quantitatively evaluate the influencing factors such as the chemical composition of the steel material and the welding conditions.
【０００５】小型の溶接部疲労試験片を用いることによ
り繰り返し荷重を低下させ、周波数を高くして疲労試験
を比較的短時間に実施することも可能である。しかし、
この方法においても疲労強度のばらつきは大きいために
影響因子の抽出・定量的評価は困難である。By using a small weld fatigue test piece, it is possible to reduce the cyclic load and increase the frequency to carry out the fatigue test in a relatively short time. But,
Even with this method, it is difficult to extract and quantitatively evaluate the influential factors because the fatigue strength varies widely.
【０００６】このように、従来の実溶接継手の疲労試験
は鋼材の化学成分やミクロ組織が溶接部疲労強度に及ぼ
す影響を迅速・簡易に調査する上で困難があった。As described above, the conventional fatigue test of actual welded joints has been difficult to quickly and easily investigate the influence of the chemical composition and microstructure of steel on the fatigue strength of welds.
【０００７】[0007]
【発明が解決しようとする課題】上記のように実溶接継
手の疲労試験においては、（１）試験片が大型となるた
めに試験片に負荷する繰り返し荷重が高くなり繰り返し
荷重の周波数を高くすることができず、試験に多大の時
間を要する、（２）疲労強度のばらつきが大きくなるこ
とが多く、疲労強度を支配する要因を抽出・定量評価す
ることが困難な場合が多い、の問題があった。As described above, in the fatigue test of the actual welded joint, (1) since the test piece is large, the repetitive load applied to the test piece is high and the frequency of the repetitive load is high. However, the test requires a lot of time, and (2) the variation in fatigue strength is often large, and it is often difficult to extract and quantitatively evaluate the factors that govern fatigue strength. there were.
【０００８】本発明は実際に溶接を行わずに鋼材の溶接
熱影響部における疲労破壊感受性を簡便・迅速に評価で
きる試験法を提供することを目的とする。It is an object of the present invention to provide a test method capable of easily and quickly evaluating the fatigue fracture susceptibility in a weld heat affected zone of steel without actually performing welding.
【０００９】[0009]
【課題を解決するための手段】本発明は前記課題を解決
するものであって、溶接構造用鋼から加工した試験片
に、Ａｃ3 変態点以上まで加熱した後８００℃から５０
０℃間の平均冷却速度が２〜３００℃／秒で１００℃以
下まで冷却する熱履歴を与え、この熱履歴賦与部に応力
集中係数が２．０〜２０．０となる切欠を加工し、この
切欠付き試験片に繰り返し応力を賦与して疲労破壊させ
ることを特徴とする溶接熱影響部の疲労破壊感受性評価
試験法である。Means for Solving the Problems The present invention is to solve the above problems, in which a test piece machined from welded structural steel is heated to a temperature above the Ac 3 transformation point and then heated at 800 ° C. to 50 ° C.
A heat history of cooling to 100 ° C. or less at an average cooling rate of 0 ° C. of 2 to 300 ° C./second is applied, and a notch having a stress concentration coefficient of 2.0 to 20.0 is processed in the heat history imparting portion, This is a fatigue fracture susceptibility evaluation test method for a weld heat affected zone, which is characterized by applying repeated stress to this notched test piece to cause fatigue fracture.
【００１０】[0010]
【作用】本発明者らは溶接継手の止端部から発生する疲
労き裂を詳細に観察した結果、疲労き裂が最も発生しや
すい位置は、応力集中が高く最終溶接パスにより形成さ
れる溶接融合線に極めて近い粗粒の熱影響部（以下、Ｈ
ＡＺと記す）であり、ここから発生した疲労き裂はＨＡ
Ｚ内を伝播した後、母材部に突入・伝播し、試験片の最
終破断にいたること、さらに、破断にいたる繰り返し数
のうちＨＡＺからのき裂発生およびＨＡＺ内のき裂伝播
が大部分を占め、母材部における伝播の繰り返し数は相
対的に少ないことを知見した。すなわち、母材組織の影
響は少なく、ＨＡＺ組織の影響が非常に大きい。As a result of detailed observation of the fatigue cracks generated from the toe of the welded joint, the present inventors found that the position where the fatigue cracks are most likely to occur is a weld formed by the final welding pass where stress concentration is high. Coarse-grained heat-affected zone (hereinafter H
AZ), and the fatigue crack generated from this is HA
After propagating in Z, it rushes into and propagates in the base metal part, leading to the final fracture of the test piece, and in the number of repetitions leading to fracture, crack initiation from HAZ and crack propagation in HAZ are mostly It was found that the number of repetitions of propagation in the base metal was relatively small. That is, the influence of the base material structure is small, and the influence of the HAZ structure is very large.
【００１１】従って、溶接止端部に一致するＨＡＺから
疲労き裂が発生・伝播する場合の疲労破壊を再現するた
めには第一にＨＡＺの組織を再現する必要があることを
結論するに至った。Therefore, it is concluded that the structure of the HAZ must be reproduced first in order to reproduce the fatigue fracture when the fatigue crack is generated and propagates from the HAZ that coincides with the weld toe. It was
【００１２】一方、疲労強度は応力集中度に大きく依存
することは公知の事実である。従って、溶接止端部ＨＡ
Ｚからの疲労き裂発生と伝播を再現するためにはＨＡＺ
の組織を再現するだけでなく応力集中をも再現する必要
がある。疲労き裂の発生・伝播は応力集中の影響を強く
受けるためにＨＡＺ組織を再現しただけでは実継手止端
部ＨＡＺからの疲労破壊を再現できない。逆に、疲労き
裂の発生・伝播はミクロ組織の影響も強く受けるために
応力集中を再現しただけでは実継手止端部ＨＡＺからの
疲労破壊を再現できない。ミクロ組織と応力集中の両者
を同時に再現することによってはじめて止端部ＨＡＺか
らの疲労き裂発生と伝播を再現できることが可能とな
る。On the other hand, it is a known fact that the fatigue strength greatly depends on the stress concentration. Therefore, the weld toe HA
To reproduce fatigue crack initiation and propagation from Z, HAZ
It is necessary to reproduce not only the structure of, but also the stress concentration. Since the initiation and propagation of fatigue cracks are strongly influenced by stress concentration, it is not possible to reproduce the fatigue fracture from the actual joint toe HAZ simply by reproducing the HAZ structure. On the contrary, since the initiation and propagation of fatigue cracks are strongly influenced by the microstructure, the fatigue fracture from the actual joint toe HAZ cannot be reproduced only by reproducing the stress concentration. It is only possible to reproduce the fatigue crack initiation and propagation from the toe HAZ by reproducing both the microstructure and the stress concentration at the same time.
【００１３】すなわち、再現熱サイクルを鋼材に賦与す
ることにより止端部ＨＡＺのミクロ組織を再現し、この
再現ＨＡＺ材から応力集中を付けた試験片を加工し疲労
試験に供することにより、実継手止端部ＨＡＺと冶金的
・力学的に等価な状況を再現することができる。これに
より実溶接継手の疲労試験を行わずとも鋼材のＨＡＺ疲
労破壊感受性を迅速・簡易に評価することが可能とな
る。That is, the microstructure of the toe HAZ is reproduced by applying a reproduced heat cycle to the steel material, and a stress-concentrated test piece is machined from this reproduced HAZ material and subjected to a fatigue test to obtain an actual joint. It is possible to reproduce a situation that is metallurgically and mechanically equivalent to the toe HAZ. As a result, it becomes possible to quickly and easily evaluate the HAZ fatigue fracture susceptibility of the steel material without performing the fatigue test of the actual welded joint.
【００１４】前記の知見をもとに本発明による試験法の
条件を限定した理由を以下に述べる。溶接止端部におい
て応力集中が高く、疲労き裂が発生しやすいのはＨＡＺ
であり、本発明試験法においてもＨＡＺ組織を再現する
必要がある。ＨＡＺ組織を再現するためには試験片をＡ
ｃ3 変態点以上に加熱することが必要であるので、加熱
温度をＡｃ3 変態点以上とした。ＨＡＺのなかでも特に
応力集中が高くなるのは溶接融合線直近のベイナイトあ
るいはマルテンサイトを主体とする粗粒のＨＡＺであ
る。この組織を再現するためには試験片を１２００℃以
上に加熱することが望ましい。加熱速度は特に限定しな
いが、実溶接継手の熱履歴における加熱速度にできるだ
け近いことが望ましい。手溶接、ガスシールド溶接など
の比較的入熱が小さい溶接を再現するためには加熱速度
を２００℃／秒以上とすることが望ましい。加熱方式は
抵抗加熱、高周波加熱など方式を問わない。The reason why the conditions of the test method according to the present invention are limited based on the above findings will be described below. HAZ has high stress concentration at the weld toe and is susceptible to fatigue cracks.
Therefore, it is necessary to reproduce the HAZ structure in the test method of the present invention. In order to reproduce the HAZ structure, the test piece A
Since it is necessary to heat above the c 3 transformation point, the heating temperature was set to the Ac 3 transformation point or above. Among HAZs, particularly high stress concentration is in coarse-grained HAZ mainly composed of bainite or martensite in the vicinity of the welding fusion line. In order to reproduce this structure, it is desirable to heat the test piece to 1200 ° C or higher. The heating rate is not particularly limited, but it is desirable to be as close as possible to the heating rate in the thermal history of the actual welded joint. In order to reproduce welding with relatively small heat input such as manual welding and gas shield welding, it is desirable to set the heating rate to 200 ° C./sec or more. The heating method may be resistance heating or high frequency heating.
【００１５】実溶接継手のＨＡＺにおいては最高加熱温
度に加熱された後に急冷されてベイナイトあるいはマル
テンサイトを含む粗粒組織が生成される。再現ＨＡＺ材
においてもこの組織を再現することが必須であり、この
ためには８００℃から５００℃における平均冷却速度を
２℃／秒以上とする必要がある。２℃／秒未満の冷却速
度ではフェライトの生成量が増加してＨＡＺ組織を再現
することができない。８００℃から５００℃における平
均冷却速度が２℃／秒以上であれば概略実継手のＨＡＺ
組織を再現できるが、実継手の溶接条件に合わせて冷却
速度を設定することが望ましい。冷却速度を算定する式
はたとえば佐藤邦彦ほか著「溶接工学」（理工学社、１
９７９年）第３９〜４１頁にその記載がある。入熱が５
０ｋＪ／ｃｍ以下の小・中入熱溶接のＨＡＺを再現する
場合には平均冷却速度を１０℃／秒以上とすることが望
ましい。逆に冷却速度が３００℃／秒を超えると、完全
焼入れ組織が生成し、実継手のＨＡＺ組織を再現できな
い。このため、冷却速度の上限を３００℃／秒とした。In the HAZ of the actual welded joint, it is heated to the maximum heating temperature and then rapidly cooled to form a coarse grain structure containing bainite or martensite. It is essential to reproduce this structure also in the reproduced HAZ material, and for this purpose, it is necessary to set the average cooling rate from 800 ° C. to 500 ° C. to 2 ° C./sec or more. If the cooling rate is less than 2 ° C./sec, the amount of ferrite produced increases and the HAZ structure cannot be reproduced. If the average cooling rate from 800 ° C to 500 ° C is 2 ° C / sec or more, the HAZ of the actual joint
Although the structure can be reproduced, it is desirable to set the cooling rate according to the welding conditions of the actual joint. The formula for calculating the cooling rate is, for example, Kunihiko Sato et al., "Welding Engineering" (Science and Engineering, 1
(1997) pages 39 to 41. Heat input is 5
When reproducing the HAZ of small / medium heat input welding of 0 kJ / cm or less, it is desirable to set the average cooling rate to 10 ° C./second or more. On the contrary, if the cooling rate exceeds 300 ° C./sec, a completely quenched structure is generated and the HAZ structure of the actual joint cannot be reproduced. Therefore, the upper limit of the cooling rate is set to 300 ° C./second.
【００１６】次に、応力集中係数を限定した根拠を述べ
る。実溶接継手の止端部の応力集中係数は継手形状、溶
接法、溶接入熱などによって変化するが、概ね２以上で
ある。従って、本発明の再現試験において応力集中係数
を２．０以上とすれば実継手の止端部における応力状態
をほぼ再現できる。応力集中係数が２．０未満では応力
集中が低すぎるために疲労強度は再現ＨＡＺ材の強度の
みに依存するようになり、実継手での疲労破壊を再現で
きない。従って、応力集中係数の下限値を２．０とし
た。逆に、応力集中係数が２０．０を超えると、き裂発
生寿命が極端に短くなり、伝播寿命だけが支配的となる
ために実継手の止端部からの疲労き裂発生・伝播を再現
できない。従って、応力集中係数の上限を２０．０とし
た。応力集中係数がこの範囲であれば実継手止端部の応
力状態をほぼ再現できるが、再現ＨＡＺ材の応力集中係
数を、対象とする継手の応力集中係数と同一とすること
が望ましい。実溶接継手の応力集中係数に関しては、た
とえば前掲ガーニィ著「溶接構造の疲れ」第２２〜３１
頁にその記載がある。また、再現ＨＡＺ材の応力集中係
数に関しては、たとえばＲ．Ｊ．Ｒｏａｒｋ、Ｗ．Ｃ．
Ｙｏｕｎｇ著「Ｆｏｒｍｕｌａｓ ｆｏｒ Ｓｔｒｅｓ
ｓ ａｎｄ Ｓｔｒａｉｎ」（ＭｃＧｒａｗ−Ｈｉｌｌ
Ｋｏｇａｋｕｓｈａ刊、１９７５年）にその計算方法
の記載がある。応力集中係数が２．０〜２０．０の範囲
であればその他の試験片形状、応力負荷方式は特に限定
しない。すなわち、切欠付き曲げ試験、切欠付き丸棒引
張り試験、切欠付き丸棒回転曲げ試験などが本発明に適
した試験法である。Next, the basis for limiting the stress concentration factor will be described. The stress concentration factor at the toe of the actual welded joint varies depending on the joint shape, welding method, welding heat input, etc., but is generally 2 or more. Therefore, in the reproduction test of the present invention, if the stress concentration factor is 2.0 or more, the stress state at the toe portion of the actual joint can be almost reproduced. If the stress concentration factor is less than 2.0, the stress concentration is too low, and the fatigue strength depends only on the strength of the reproduced HAZ material, and the fatigue fracture in the actual joint cannot be reproduced. Therefore, the lower limit of the stress concentration factor is set to 2.0. Conversely, if the stress concentration factor exceeds 20.0, the crack initiation life will be extremely short and only the propagation life will be dominant, so the fatigue crack initiation and propagation from the toe of the actual joint will be reproduced. Can not. Therefore, the upper limit of the stress concentration factor is set to 20.0. If the stress concentration factor is within this range, the stress state at the toe of the actual joint can be almost reproduced, but it is desirable that the stress concentration factor of the reproduced HAZ material be the same as the stress concentration factor of the target joint. Regarding the stress concentration factor of the actual welded joint, see, for example, Garnie, “Fatigue of Welded Structure”, 22-31.
The description is on the page. Further, regarding the stress concentration factor of the reproduced HAZ material, for example, R.S. J. Roark, W.A. C.
Young by "Formulas for Stress"
s and Strain "(McGraw-Hill
The calculation method is described in Kogakusha, 1975). Other test piece shapes and stress loading methods are not particularly limited as long as the stress concentration factor is in the range of 2.0 to 20.0. That is, the notch bending test, the notch round bar tensile test, the notch round bar rotating bending test, and the like are test methods suitable for the present invention.
【００１７】本発明における疲労試験は基本的に大気中
における溶接継手疲労強度を再現するための試験であ
り、大気中で繰り返し荷重が負荷される。また、繰り返
し荷重の周波数に対する限定はない。しかし、海水など
腐食環境中における溶接継手の腐食疲労を再現する場合
においては相当する環境中で再現ＨＡＺ試験片に繰り返
し荷重を負荷することにより実継手の腐食疲労を再現で
きる。The fatigue test in the present invention is basically a test for reproducing the fatigue strength of a welded joint in the atmosphere, and a repeated load is applied in the atmosphere. Further, there is no limitation on the frequency of the repeated load. However, when reproducing the corrosion fatigue of a welded joint in a corrosive environment such as seawater, the corrosion fatigue of the actual joint can be reproduced by repeatedly applying a load to the reproduced HAZ test piece in a corresponding environment.
【００１８】本発明による試験法は溶接止端部ＨＡＺか
らの疲労破壊を再現し、鋼材のＨＡＺ疲労破壊感受性を
評価することを目的とするものであるが、実溶接継手の
疲労破壊の応力値または破断繰り返し数を推定すること
を目的としたものではない。The test method according to the present invention is intended to reproduce the fatigue fracture from the weld toe HAZ and evaluate the HAZ fatigue fracture susceptibility of the steel material. Or, it is not intended to estimate the number of repeated fractures.
【００１９】[0019]
【実施例】以下に、実施例について説明する。表１に供
試鋼の化学成分と母材の引張り特性を示す。板厚は１５
ｍｍである。表２に示す溶接条件でＴ字隅肉溶接継手を
作成し、図１に示す形状の試験片を用いて３点曲げ疲労
試験を実施し、表３に示す疲労試験結果を得た。図中
１，２は鋼板、３は溶接ビード、４は３点曲げの荷重賦
与のアンビルである。これを参照データとする。５×１
０6 回および２×１０6 回における疲労強度はいずれも
鋼Ａ，Ｂ，Ｃの順に高くなった。上記のように、本発明
試験法は実継手における疲労破壊の応力値や破断繰り返
し数を推定するものではなく、鋼材熱影響部の疲労破壊
感受性を評価するものである。従って、表３で示した実
継手疲労試験結果の鋼材による序列が本発明試験法で再
現できれば、本発明試験法は疲労破壊感受性を評価する
試験法として有効であると判断できる。EXAMPLES Examples will be described below. Table 1 shows the chemical composition of the sample steel and the tensile properties of the base metal. Board thickness is 15
mm. A T-shaped fillet welded joint was prepared under the welding conditions shown in Table 2 and a three-point bending fatigue test was carried out using the test piece having the shape shown in FIG. 1 to obtain the fatigue test results shown in Table 3. In the figure, 1 and 2 are steel plates, 3 is a weld bead, and 4 is a three-point bending load-applying anvil. This is used as reference data. 5 x 1
The fatigue strengths at 0 6 times and 2 × 10 6 times all increased in the order of steels A, B, and C. As described above, the test method of the present invention does not estimate the stress value of fatigue fracture or the number of repeated fractures in the actual joint, but evaluates the fatigue fracture susceptibility of the steel heat-affected zone. Therefore, if the order of steel of the actual joint fatigue test results shown in Table 3 can be reproduced by the test method of the present invention, the test method of the present invention can be judged to be effective as a test method for evaluating fatigue fracture susceptibility.
【００２０】[0020]
【表１】 [Table 1]
【００２１】[0021]
【表２】 [Table 2]
【００２２】[0022]
【表３】 [Table 3]
【００２３】表４および表５に再現ＨＡＺ材の疲労試験
結果を示す。番号１〜３は本発明試験法であり、図２に
示す断面角型の切欠付き試験片を用いた。図中Ｌは切欠
深さ、Ｒは切欠先端半径（図面の大きさの都合上、矢印
そのものは半径を示していない）、Ｗは試験片の幅を示
す。疲労限および５×１０6 回、２×１０6 回における
疲労強度はいずれも鋼Ａ，Ｂ，Ｃの順に高く、表３に示
した実継手における疲労強度と同一の順序となってお
り、鋼材による疲労強度の差を再現している。番号４〜
６は同じく図２に示す断面角型の切欠付き試験片を用い
たが、最高加熱温度が７００℃でＡｃ3 変態点未満であ
りＨＡＺ組織を再現していない。このために疲労強度は
鋼Ｂ，Ｃ，Ａの順に高く、実継手の疲労強度の鋼材の順
序と一致しない。番号７〜９は図３に示す切欠付き丸棒
引張り試験片を用いた本発明試験法である。図中Ｄは試
験片の直径でＬ，Ｒは図２と同様である。鋼Ａ，Ｂ，Ｃ
の順に疲労強度が高く、鋼材による疲労強度の差を再現
している。番号１０〜１２は図３に示す切欠付き丸棒回
転曲げ疲労試験片を用いた本発明試験法である。鋼Ａ，
Ｂ，Ｃの順に疲労強度が高く、実継手の疲労破壊を再現
している。番号１３〜１５は図２に示す断面角型の切欠
付き３点曲げ試験片を用いた疲労試験であるが、応力集
中係数が２．０未満の比較試験法である。疲労強度の順
序は表３に示した実継手の疲労強度の順序と一致せず、
実継手の疲労破壊を再現していないことは明らかであ
る。以上の結果から本発明試験法により実溶接継手の疲
労破壊を再現できることが明らかとなった。Tables 4 and 5 show the fatigue test results of the reproduced HAZ materials. Numbers 1 to 3 are test methods of the present invention, and the test piece with a cutout having a square cross section shown in FIG. 2 was used. In the drawing, L is the notch depth, R is the radius of the notch tip (the arrow itself does not indicate the radius due to the size of the drawing), and W is the width of the test piece. Fatigue strength and fatigue strength at 5 × 10 6 times and 2 × 10 6 times are higher in the order of steels A, B, and C, which is the same order as the fatigue strength of actual joints shown in Table 3. The difference in fatigue strength due to is reproduced. Number 4 ~
No. 6 also used a notched test piece having a rectangular cross section shown in FIG. 2, but the maximum heating temperature was 700 ° C. and was below the Ac 3 transformation point, and the HAZ structure was not reproduced. Therefore, the fatigue strength is higher in the order of steels B, C, and A, which does not match the order of the fatigue strength steel materials of the actual joint. Numbers 7 to 9 are test methods of the present invention using the notched round bar tensile test piece shown in FIG. In the figure, D is the diameter of the test piece, and L and R are the same as in FIG. Steel A, B, C
The fatigue strength is higher in the order of, and the difference in fatigue strength due to steel materials is reproduced. Numbers 10 to 12 are the test methods of the present invention using the notched round bar rotary bending fatigue test piece shown in FIG. Steel A,
The fatigue strength is higher in the order of B and C, and the fatigue fracture of the actual joint is reproduced. Nos. 13 to 15 are fatigue tests using a notched three-point bending test piece having a square cross section shown in FIG. The order of fatigue strength does not match the order of fatigue strength of actual joints shown in Table 3,
It is clear that the fatigue fracture of the actual joint is not reproduced. From the above results, it became clear that the fatigue fracture of the actual welded joint can be reproduced by the test method of the present invention.
【００２４】[0024]
【表４】 [Table 4]
【００２５】[0025]
【表５】 [Table 5]
【００２６】[0026]
【発明の効果】本発明による再現ＨＡＺ材の疲労試験は
実溶接継手の疲労試験を実施しなくても簡便かつ迅速に
鋼材のＨＡＺ疲労破壊感受性を評価することができ、鋼
材の選定などに利用でき、鋼構造物の疲労破壊防止、極
めて価値の高いものである。The fatigue test of the reproduced HAZ material according to the present invention enables the HAZ fatigue fracture susceptibility of the steel material to be evaluated simply and quickly without performing the fatigue test of the actual welded joint, and is used for selecting the steel material. It is possible to prevent fatigue damage of steel structures and is extremely valuable.
【図１】Ｔ字隅肉溶接継手疲労試験片の形状を示す図FIG. 1 is a diagram showing the shape of a T-shaped fillet welded joint fatigue test piece.
【図２】切欠付き３点曲げ疲労試験片の形状を示す図FIG. 2 is a diagram showing the shape of a notched three-point bending fatigue test piece.
【図３】円周切欠付き引張りまたは回転曲げ疲労試験片
の形状を示す図FIG. 3 is a diagram showing the shape of a tensile or rotary bending fatigue test piece with a circumferential notch.
Claims (1)
ｃ3 変態点以上まで加熱した後８００℃から５００℃間
の平均冷却速度が２〜３００℃／秒で１００℃以下まで
冷却する熱履歴を与え、この熱履歴賦与部に応力集中係
数が２．０〜２０．０となる切欠を加工し、この切欠付
き試験片に繰り返し応力を賦与して疲労破壊させること
を特徴とする溶接熱影響部の疲労破壊感受性評価試験
法。1. A test piece machined from welded structural steel comprises:
c 3 average cooling rate between 500 ° C. from 800 ° C. After heating to above the transformation point gives heat history to cool to 100 ° C. or less at 2 to 300 ° C. / sec, the stress concentration factor in the thermal history imparted portion 2. A fatigue fracture susceptibility evaluation test method for a welded heat-affected zone, which is characterized in that a notch having a size of 0 to 20.0 is processed, and stress is repeatedly applied to the notched test piece to cause fatigue fracture.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27117793A JPH07103871A (en) | 1993-10-05 | 1993-10-05 | Method for evaluating fatigue fracture sensibility at part subjected to welding heat |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27117793A JPH07103871A (en) | 1993-10-05 | 1993-10-05 | Method for evaluating fatigue fracture sensibility at part subjected to welding heat |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07103871A true JPH07103871A (en) | 1995-04-21 |
Family
ID=17496423
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP27117793A Withdrawn JPH07103871A (en) | 1993-10-05 | 1993-10-05 | Method for evaluating fatigue fracture sensibility at part subjected to welding heat |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07103871A (en) |
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|---|---|---|---|---|
| KR100483823B1 (en) * | 2002-11-21 | 2005-04-20 | 한국기계연구원 | Manufacturing Method of Welded Specimen with Internal Fatigue Cracks |
| CN102192858A (en) * | 2010-02-26 | 2011-09-21 | 株式会社神户制钢所 | Fatigue characteristic evaluation method for t joint part of t-type welding joint structure |
| JP2012502267A (en) * | 2008-09-08 | 2012-01-26 | アルケマ フランス | Method for setting the fatigue life of a polymer composition |
| JP2013057646A (en) * | 2011-09-09 | 2013-03-28 | Kobe Steel Ltd | Fatigue characteristic evaluation method of t joint part in t-shaped welded joint structure |
| JP2017173314A (en) * | 2016-03-18 | 2017-09-28 | Ｊｆｅスチール株式会社 | Fatigue crack generation life evaluation test method of weld heat-affected zone, method for manufacturing flat plate test piece, and flat plate test piece |
| JP2017187408A (en) * | 2016-04-07 | 2017-10-12 | 新日鐵住金株式会社 | Quality assurance method of steel material and fatigue characteristics estimation method |
| CN108562504A (en) * | 2015-05-21 | 2018-09-21 | 江苏理工学院 | The test method of test material fatigue strength |
-
1993
- 1993-10-05 JP JP27117793A patent/JPH07103871A/en not_active Withdrawn
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100483823B1 (en) * | 2002-11-21 | 2005-04-20 | 한국기계연구원 | Manufacturing Method of Welded Specimen with Internal Fatigue Cracks |
| JP2012502267A (en) * | 2008-09-08 | 2012-01-26 | アルケマ フランス | Method for setting the fatigue life of a polymer composition |
| US8627713B2 (en) | 2008-09-08 | 2014-01-14 | Arkema France | Method for predetermining the fatigue life of polymer composition |
| CN102192858A (en) * | 2010-02-26 | 2011-09-21 | 株式会社神户制钢所 | Fatigue characteristic evaluation method for t joint part of t-type welding joint structure |
| JP2013057646A (en) * | 2011-09-09 | 2013-03-28 | Kobe Steel Ltd | Fatigue characteristic evaluation method of t joint part in t-shaped welded joint structure |
| CN108562504A (en) * | 2015-05-21 | 2018-09-21 | 江苏理工学院 | The test method of test material fatigue strength |
| JP2017173314A (en) * | 2016-03-18 | 2017-09-28 | Ｊｆｅスチール株式会社 | Fatigue crack generation life evaluation test method of weld heat-affected zone, method for manufacturing flat plate test piece, and flat plate test piece |
| JP2017187408A (en) * | 2016-04-07 | 2017-10-12 | 新日鐵住金株式会社 | Quality assurance method of steel material and fatigue characteristics estimation method |
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