JP2003035644A - Method and equipment for thermal fatigue test - Google Patents
Method and equipment for thermal fatigue testInfo
- Publication number
- JP2003035644A JP2003035644A JP2001222081A JP2001222081A JP2003035644A JP 2003035644 A JP2003035644 A JP 2003035644A JP 2001222081 A JP2001222081 A JP 2001222081A JP 2001222081 A JP2001222081 A JP 2001222081A JP 2003035644 A JP2003035644 A JP 2003035644A
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- Japan
- Prior art keywords
- thermal fatigue
- fatigue test
- test piece
- holder
- thermal
- 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.)
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- Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
Abstract
Description
【０００１】[0001]
【技術分野】本発明は，金属，セラミックス等の材料，
特にピストン用アルミ合金の耐熱疲労性の評価に利用す
ることが可能な簡易な熱疲労試験方法および熱疲労試験
装置に関する。TECHNICAL FIELD The present invention relates to materials such as metals and ceramics,
In particular, the present invention relates to a simple thermal fatigue test method and thermal fatigue test apparatus that can be used to evaluate the thermal fatigue resistance of aluminum alloys for pistons.
【０００２】[0002]
【従来技術】金属，セラミックス等の材料熱疲労特性を
評価する試験方法としては，油圧サーボ試験機を用いた
熱疲労試験方法が最も一般的に使用されている。この方
法は高周波加熱とエアー冷却により熱疲労試験片に温度
変化を与え，高温伸び計を用いて熱疲労試験片に発生し
た伸びを検出し，またロ−ドセルを用いて熱疲労試験片
に発生した荷重を検出する方法で，油圧サーボ機構によ
って伸びと荷重を制御するものである。2. Description of the Related Art A thermal fatigue test method using a hydraulic servo tester is most commonly used as a test method for evaluating thermal fatigue properties of materials such as metals and ceramics. In this method, a temperature change is applied to a thermal fatigue test piece by high frequency heating and air cooling, the elongation generated in the thermal fatigue test piece is detected using a high temperature extensometer, and the thermal fatigue test piece is generated using a load cell. This method detects the applied load and controls the elongation and load using a hydraulic servo mechanism.
【０００３】しかし，この方法には，以下のような問題
点があった。高周波加熱装置，油圧サーボ機構等からな
るため装置が大がかりで，複雑かつ高価である。また，
熱疲労試験片が大形のため部品から直接採取できないと
いう問題がある。さらに，熱疲労試験片がアルミニウム
合金の場合は熱伝導が良いためチャック部から熱が逃げ
てしまい熱疲労試験片の温度差が大きくなるという欠点
があった。However, this method has the following problems. Since it consists of a high-frequency heating device, hydraulic servo mechanism, etc., the device is large and complicated and expensive. Also,
There is a problem that the thermal fatigue test piece cannot be taken directly from the component because it is large. Further, when the thermal fatigue test piece is an aluminum alloy, the heat conduction is good, so that heat escapes from the chuck portion, and the temperature difference of the thermal fatigue test piece becomes large.
【０００４】加えてピストン用アルミ合金の場合，試験
すべき上限温度が３００℃以上と高いため，試験片が軟
化して伸び計の接触子が試験片に食い込み，それが原因
で破断したり，試験片の変形が大きくて接触子が外れた
りする致命的な問題があった。In addition, in the case of aluminum alloys for pistons, since the upper limit temperature to be tested is as high as 300 ° C. or higher, the test piece softens and the contact of the extensometer digs into the test piece, causing breakage, There was a fatal problem that the test piece was greatly deformed and the contactor came off.
【０００５】また，比較的簡易な熱疲労試験方法として
は，熱疲労試験片自体に温度分布を生じさせ，発生した
熱ひずみによって熱疲労試験片を破損させて熱疲労寿命
を評価する方法がある（特開昭６０−２４９０３５
号）。この方法はそろばん玉状の熱疲労試験片全体を加
熱・冷却するものであるが熱サイクルに伴う熱応力およ
び熱ひずみの状態が複雑となり定量的な熱疲労寿命の評
価ができないという問題点があった。As a relatively simple thermal fatigue test method, there is a method in which a temperature distribution is generated in the thermal fatigue test piece itself and the thermal fatigue test piece is damaged by the generated thermal strain to evaluate the thermal fatigue life. (Japanese Patent Laid-Open No. 60-249035
issue). This method heats and cools the entire abacus bead-shaped thermal fatigue test piece, but it has the problem that the state of thermal stress and thermal strain associated with the thermal cycle becomes complicated and quantitative thermal fatigue life cannot be evaluated. It was
【０００６】これらの従来の方法に対し，簡易な構成で
材料間の熱膨張差を駆動力として熱疲労特性の評価がで
きるという特徴を持つ試験方法が特開平７−２００３１
号公報において提案されている。この方法は，比較的低
温の領域における試験では非常に有効である。In contrast to these conventional methods, there is a test method characterized in that thermal fatigue characteristics can be evaluated by using a difference in thermal expansion between materials as a driving force with a simple structure.
It is proposed in the publication. This method is very effective for testing in the relatively low temperature range.
【０００７】[0007]
【解決しようとする課題】しかしながら，上記方法で
は，試験上限温度が例えば３００℃以上になると，ホル
ダの材質によっては，熱膨張係数の温度依存性が大き
く，それに伴い熱疲労試験片に生じひずみ挙動も温度依
存性を持っため，信頼できる一般的な熱疲労特性が評価
できないという問題があった。However, in the above method, when the test upper limit temperature is, for example, 300 ° C. or higher, the temperature dependence of the thermal expansion coefficient is large depending on the material of the holder, and the strain behavior generated in the thermal fatigue test piece is accordingly accompanied. Also has a temperature dependency, so there is a problem that reliable general thermal fatigue properties cannot be evaluated.
【０００８】また，試験上限温度が３００℃以上という
高温になると，熱疲労試験片の軟化が著しく，熱疲労試
験片とホルダの結合手段が緩み，熱疲労試験片に生じる
全ひずみ範囲が低下し，試験結果の定量性が低下すると
いう問題があった。このような問題によって，上記従来
の方法では，例えば実使用温度が３００℃以上というピ
ストンに用いられるアルミ合金に対して有効な熱疲労試
験を行うことは困難であった。When the test upper limit temperature is as high as 300 ° C. or higher, the thermal fatigue test piece is significantly softened, the coupling means between the thermal fatigue test piece and the holder is loosened, and the total strain range generated in the thermal fatigue test piece is reduced. However, there was a problem that the quantitativeness of the test results decreased. Due to such a problem, it is difficult to perform an effective thermal fatigue test on an aluminum alloy used for a piston having an actual operating temperature of 300 ° C. or higher by the above conventional method.
【０００９】本発明はかかる従来の問題点に鑑みてなさ
れたもので，高温で使用される材料に対しても有効な熱
疲労試験片を簡易に実施することができる，熱疲労試験
方法及び熱疲労試験装置を提供しようとするものであ
る。The present invention has been made in view of the above conventional problems, and a thermal fatigue test method and a thermal fatigue test method capable of easily carrying out a thermal fatigue test piece effective for a material used at a high temperature. It is intended to provide a fatigue test device.
【００１０】[0010]
【課題の解決手段】第１の発明は，中央部に両端部より
も断面積が小さな評価部分を有する棒状の熱疲労試験片
と，試験温度範囲において上記熱疲労試験片より熱膨張
係数が小さく，かつ熱膨張係数が急激に変化する温度特
異点が存在しない低膨張材料からなり，上記熱疲労試験
片の両端部と接触する両側の固定端部に複数のＶ字形の
刃を設けた２枚のホルダとを用意し，上記熱疲労試験片
をその両側から上記ホルダによって挟持するように拘束
するに際し，上記ホルダの上記刃を上記熱疲労試験片の
両端部に圧入するとともに，上記熱疲労試験片の両端部
と上記ホルダの上記固定端部との間の結合の緩みを防止
するために弾性部材を介して結合手段によって上記熱疲
労試験片の両端部と上記ホルダの上記固定端部とを拘束
し，この拘束状態のまま上記熱疲労試験片および上記ホ
ルダの全体に対して加熱・冷却サイクルを繰り返し行う
と共に，上記熱疲労試験片の両端部と上記ホルダの固定
端部との間の結合力が低下することを抑制するための上
記結合手段の増し締めを少なくとも試験中に１回行い，
上記熱疲労試験片と上記ホルダとの熱膨張差により生じ
る熱ひずみを上記熱疲労試験片の上記評価部分に局所的
に集中させ，上記熱疲労試験片が破断した際の上記加熱
・冷却サイクルのサイクル数により熱疲労寿命を求める
ことを特徴とする熱疲労試験方法にある（請求項１）。According to a first aspect of the present invention, a rod-shaped thermal fatigue test piece has a central portion having an evaluation portion having a smaller cross-sectional area than both end portions, and a thermal expansion coefficient smaller than that of the above thermal fatigue test piece in a test temperature range. , And two pieces of V-shaped blades made of a low expansion material that does not have a temperature singularity where the coefficient of thermal expansion changes abruptly, and a plurality of V-shaped blades are provided at the fixed ends on both sides that contact both ends of the thermal fatigue test piece. And the holder for holding the thermal fatigue test piece so as to be sandwiched by the holder from both sides thereof, the blade of the holder is press-fitted into both ends of the thermal fatigue test piece, and the thermal fatigue test is performed. Both ends of the thermal fatigue test piece and the fixed end of the holder by a connecting means via elastic members to prevent loosening of the connection between both ends of the piece and the fixed end of the holder. Restrained, this restrained state The heating / cooling cycle is repeated for the entire thermal fatigue test piece and the holder as it is, and the decrease in the bonding force between the both ends of the thermal fatigue test piece and the fixed end of the holder is suppressed. Retightening the coupling means for at least once during the test,
The thermal strain caused by the difference in thermal expansion between the thermal fatigue test piece and the holder is locally concentrated in the evaluation part of the thermal fatigue test piece, and the heating / cooling cycle of the heating / cooling cycle when the thermal fatigue test piece is broken. A thermal fatigue test method is characterized in that the thermal fatigue life is obtained by the number of cycles (claim 1).
【００１１】本発明の熱疲労試験方法によって熱疲労寿
命を求めることができる理由は以下の通りであると推定
される。上記熱疲労試験片は中央部に両端部より断面積
が小さな評価部分を設ける。この断面積が小さな評価部
分を設ける理由は，以下の通りである。一般的に，熱膨
張係数αTPの熱疲労試験片に拘束なしの状態で温度変化
ΔＴを与えた時の自由膨脹ひずみ量Δεfreeは，式
（１）のようになる。
Δεfree＝αTPΔT・・・（１）The reason why the thermal fatigue life can be obtained by the thermal fatigue test method of the present invention is presumed to be as follows. The thermal fatigue test piece is provided with an evaluation portion having a smaller cross-sectional area than both end portions in the central portion. The reason for providing the evaluation part having a small cross-sectional area is as follows. Generally, the amount of free expansion strain Δε free when a temperature change ΔT is applied to a thermal fatigue test piece having a coefficient of thermal expansion α TP without restraint is given by equation (1). Δε free = α TP ΔT (1)
【００１２】この熱疲労試験片を，たとえ熱膨張係数が
低く剛性が十分に大きなホルダで拘束したとしても，熱
ひずみ量をこの自由膨脹ひずみ量以上に大きくすること
はできない。ところが，熱疲労試験片が複雑な形状をし
ている場合，すなわち局部的に断面積の小さな評価部分
がある場合には，当然そこに局部的に応力集中が生じ
る。温度変化が大きな場合にはこの局部応力が，材料が
有する降伏応力を越え，材料の一般的な応力−ひずみ特
性から材料のみかけ上の弾性率が低下するため，それ以
降はその部分にひずみが集中し，そのひずみ量は当然，
式（１）の自由膨脹ひずみ量より大きくなる。Even if the thermal fatigue test piece is restrained by a holder having a low coefficient of thermal expansion and a sufficiently large rigidity, the amount of thermal strain cannot be made larger than the amount of free expansion strain. However, when the thermal fatigue test piece has a complicated shape, that is, when there is an evaluation part with a small cross-sectional area locally, naturally stress concentration locally occurs there. When the temperature change is large, this local stress exceeds the yield stress of the material, and the apparent elastic modulus of the material decreases due to the general stress-strain characteristics of the material. Concentrate, and the amount of strain is naturally
It becomes larger than the amount of free expansion strain of Formula (1).
【００１３】そのため，本発明の熱疲労試験方法におい
ては，熱疲労試験片中央部に断面積を小さくした上記評
価部を設けることによって，自由膨脹ひずみ量より大き
なひずみの熱疲労現象を再現することができる。上記熱
疲労試験片中央部の断面積の小さな評価部分は断面積一
定の平行部とすることが望ましい。このように，平行部
を設けることによって破損位置が特定されなくなり，材
料特性のばらつきを加味した試験を行うことができるよ
うになる。Therefore, in the thermal fatigue test method of the present invention, the thermal fatigue phenomenon having a strain larger than the free expansion strain amount is reproduced by providing the above-mentioned evaluation portion having a small cross-sectional area in the central portion of the thermal fatigue test piece. You can It is desirable that the evaluation portion having a small cross-sectional area in the central portion of the thermal fatigue test piece is a parallel portion having a constant cross-sectional area. As described above, by providing the parallel portion, the damage position is not specified, and it becomes possible to perform the test in consideration of the variation in the material characteristics.
【００１４】本発明においては，上記熱疲労試験片の両
端部を，上記ホルダによって両側から拘束する。そし
て，拘束状態のまま上記熱疲労試験片およびホルダの全
体を加熱・冷却し，熱疲労試験片とホルダとの熱膨張差
による熱応力と熱ひずみを熱疲労試験片中央部の断面積
の小さな評価部分に局所的に集中させる。すなわち，熱
疲労試験片を中央にして２枚のホルダで挟み，この熱疲
労試験片をホルダごと加熱すると，ホルダの熱膨張係数
が熱疲労試験片より小さいので，熱疲労試験片の膨脹を
ホルダが阻止するため熱疲労試験片には圧縮の応力とひ
ずみが上記評価部分に集中して生じる。さらに，冷却す
ると，加熱の場合とは逆の応力とひずみが生じる。すな
わち，このように加熱と冷却を繰り返すことにより，熱
疲労試験片の上記評価部分には引張と圧縮の応力とひず
みが周期的に印加されることになり，通常の熱疲労試験
と同様に，あるサイクル数が経過すると熱疲労によって
破損が生じることになる。In the present invention, both ends of the thermal fatigue test piece are restrained from both sides by the holder. The thermal fatigue test piece and the holder as a whole are heated and cooled in the restrained state, and thermal stress and thermal strain due to the difference in thermal expansion between the thermal fatigue test piece and the holder are applied to reduce the cross-sectional area of the central part of the thermal fatigue test piece. Concentrate locally on the evaluation area. That is, when the thermal fatigue test piece is sandwiched between two holders and the thermal fatigue test piece is heated together with the holder, the thermal expansion coefficient of the holder is smaller than that of the thermal fatigue test piece. Therefore, the compressive stress and strain are generated in the thermal fatigue test piece concentrated on the evaluation portion. Furthermore, cooling causes stress and strain that are opposite to those of heating. That is, by repeating heating and cooling in this way, tensile and compressive stress and strain are cyclically applied to the above-mentioned evaluation portion of the thermal fatigue test piece, and like the normal thermal fatigue test, After a certain number of cycles, thermal fatigue causes damage.
【００１５】ここで，本発明においては，上記ホルダと
して，試験温度範囲の全域において上記熱疲労試験片よ
り熱膨張係数が小さく，かつ熱膨張係数が急激に変化す
る温度特異点，例えば磁気変態点（キュリー点）や相変
態点が存在しない低膨張材料を用いる。そのため，上記
加熱・冷却サイクルの繰り返し時においては，上記熱疲
労試験片に発生する熱歪み挙動を単純化することがで
き，熱疲労試験の信頼性を向上させることができる。Here, in the present invention, as the holder, a temperature singular point at which the coefficient of thermal expansion is smaller than that of the thermal fatigue test piece and the coefficient of thermal expansion changes abruptly over the entire test temperature range, for example, a magnetic transformation point. A low expansion material having no (Curie point) or phase transformation point is used. Therefore, when the heating / cooling cycle is repeated, the thermal strain behavior generated in the thermal fatigue test piece can be simplified and the reliability of the thermal fatigue test can be improved.
【００１６】また，本発明では，上記Ｖ字状の刃の圧
入，上記弾性部材を介した結合手段によって上記熱疲労
試験片の両端部と上記ホルダの上記固定端部とを拘束す
る。そして，加熱・冷却サイクルを繰り返し行う際に，
上記熱疲労試験片の両端部と上記ホルダの固定端部との
間の結合力が低下することを抑制するための上記結合手
段の増し締めを少なくとも１回行う。このため，試験温
度が比較的高温であっても，上記結合力が低下して熱疲
労試験片に生じる全ひずみ範囲が低下することを，十分
に防止することができる。そのため，試験結果の定量的
な信頼性を高めることができる。Further, in the present invention, both ends of the thermal fatigue test piece and the fixed end of the holder are constrained by the press-fitting of the V-shaped blade and the connecting means via the elastic member. And when repeating heating / cooling cycle,
The coupling means is retightened at least once to prevent the coupling force between the both ends of the thermal fatigue test piece and the fixed end of the holder from decreasing. Therefore, even if the test temperature is relatively high, it is possible to sufficiently prevent the binding force from being lowered and the total strain range occurring in the thermal fatigue test piece being lowered. Therefore, the quantitative reliability of the test result can be improved.
【００１７】このように，本発明の熱疲労試験方法によ
れば，高温で使用される材料に対しても有効な熱疲労試
験を簡易に実施することができる。As described above, according to the thermal fatigue test method of the present invention, it is possible to easily carry out an effective thermal fatigue test even on a material used at a high temperature.
【００１８】第２の発明は，中央部に両端部よりも断面
積が小さな評価部分を有する棒状の熱疲労試験片の熱疲
労試験を行う装置であって，試験温度範囲において上記
熱疲労試験片より熱膨張係数が小さく，かつ熱膨張係数
が急激に変化する温度特異点が存在しない低膨張材料か
らなり，上記熱疲労試験片の両端部と接触する両側の固
定端部に複数のＶ字形の刃を設けた２枚のホルダと，上
記熱疲労試験片の両側から上記ホルダによって挟持する
ように拘束するに際し，上記ホルダの上記刃を上記熱疲
労試験片の両端部に圧入するとともに，上記熱疲労試験
片の両端部と上記ホルダの上記固定端部との間の結合の
緩みを防止するために弾性部材を介して結合手段によっ
て上記熱疲労試験片の両端部と上記ホルダの上記固定端
部とを拘束した状態で上記熱疲労試験片および上記ホル
ダの全体に対して加熱・冷却サイクルを繰り返し行うた
めの加熱手段及び冷却手段とを有していることを特徴と
する熱疲労試験装置（請求項６）にある。A second aspect of the present invention is an apparatus for performing a thermal fatigue test on a rod-shaped thermal fatigue test piece having an evaluation portion having a cross-sectional area smaller than both end portions in a central portion, the thermal fatigue test piece being in the test temperature range. It consists of a low expansion material that has a smaller coefficient of thermal expansion and does not have a temperature singularity at which the coefficient of thermal expansion changes abruptly. When the two holders provided with blades are constrained so as to be sandwiched by the holders from both sides of the thermal fatigue test piece, the blades of the holder are pressed into both ends of the thermal fatigue test piece and Both ends of the thermal fatigue test piece and the fixed end of the holder are coupled by means of coupling through elastic members to prevent loosening of the connection between both ends of the fatigue test piece and the fixed end of the holder. The condition of restraining and And a heating means and a cooling means for repeatedly performing a heating / cooling cycle on the entire thermal fatigue test piece and the holder. .
【００１９】本発明の熱疲労試験装置を用いれば，上記
の優れた熱疲労試験方法を容易に実施することができ，
高温で使用される材料に対しても有効な熱疲労試験を簡
易に実施することができる。By using the thermal fatigue test apparatus of the present invention, the above excellent thermal fatigue test method can be easily carried out,
It is possible to easily carry out an effective thermal fatigue test even for materials used at high temperatures.
【００２０】[0020]
【発明の実施の形態】第１の発明（請求項１）において
は，上記熱疲労試験片の全ひずみ範囲を求めることが好
ましいが，ＦＥＭ計算や実測などにより既知の場合に
は，試験中に同時に求める必要はない。しかしながら，
全ひずみ範囲が既知でない場合には，上記熱疲労試験片
の上記評価部分に熱ひずみを測定するための歪みゲージ
を配置し，上記加熱・冷却サイクルの繰り返し時に上記
歪みゲージにより全ひずみ範囲を求めることができる
（請求項２）。BEST MODE FOR CARRYING OUT THE INVENTION In the first invention (Claim 1), it is preferable to obtain the total strain range of the thermal fatigue test piece. However, if it is known by FEM calculation or actual measurement, it is possible during the test. There is no need to ask at the same time. However,
If the total strain range is not known, a strain gauge for measuring thermal strain is placed in the evaluation part of the thermal fatigue test piece, and the total strain range is determined by the strain gauge when the heating / cooling cycle is repeated. It is possible (claim 2).
【００２１】また，上記熱疲労試験片及び上記ホルダ
は，上記試験温度範囲において上記熱疲労試験片の上記
評価部分に生じる全ひずみ範囲が０．２〜２％であり，
上記熱疲労寿命が１００〜１００００サイクルとなる様
な形状及び寸法を有するものを用いることが好ましい
（請求項３）。上記全ひずみ範囲が０．２％未満あるい
は２％を超える場合には，ピストン用アルミ合金の使用
環境に対応する有用な熱疲労寿命を得ることができな
い。また，熱疲労寿命が１００サイクル未満の試験を行
っても，実用域から外れすぎていて破壊メカニズムが実
際と異なる場合があり，有用性が低い。また，熱疲労寿
命が１００００サイクルを超えると試験時間が長すぎる
ので実用的でない。例えば後述するピストン用のアルミ
合金においては，実用寿命が上記１００〜１００００サ
イクルであるので，その範囲内において評価することが
有効である。In the thermal fatigue test piece and the holder, the total strain range generated in the evaluation portion of the thermal fatigue test piece is 0.2 to 2% in the test temperature range,
It is preferable to use one having a shape and dimensions such that the thermal fatigue life becomes 100 to 10,000 cycles (claim 3). If the total strain range is less than 0.2% or more than 2%, it is impossible to obtain a useful thermal fatigue life corresponding to the environment in which the aluminum alloy for pistons is used. Further, even if a test in which the thermal fatigue life is less than 100 cycles is performed, the fracture mechanism may be different from the actual one because it is out of the practical range, and the usefulness is low. Further, if the thermal fatigue life exceeds 10,000 cycles, the test time is too long, which is not practical. For example, in the case of an aluminum alloy for pistons, which will be described later, since the practical life is 100 to 10,000 cycles, it is effective to evaluate within that range.
【００２２】また，上記熱疲労試験片は，ピストン用ア
ルミ合金よりなり，上記試験温度範囲の上限温度が３０
０℃以上であり，上記ホルダの室温硬さがＨＶ３００以
上であり，上記ホルダの線膨張係数が５〜１８×１０-6
／℃であることが好ましい（請求項４）。上記ピストン
用アルミ合金は実際の使用温度が３００度を超える場合
があり，上記試験温度範囲の上限温度を３００℃以上と
することにより非常に実用的な試験を行うことができ
る。The thermal fatigue test piece is made of an aluminum alloy for pistons and has an upper limit temperature of 30 in the test temperature range.
The temperature is 0 ° C or higher, the room temperature hardness of the holder is HV300 or higher, and the linear expansion coefficient of the holder is 5 to 18 × 10 -6.
It is preferably / ° C (claim 4). The above-mentioned aluminum alloy for pistons may have an actual operating temperature of more than 300 ° C, and a very practical test can be performed by setting the upper limit temperature of the above test temperature range to 300 ° C or higher.
【００２３】また，上記ホルダの室温硬さがＨＶ３００
未満の場合には，ホルダによる熱疲労試験片の拘束力が
十分に得られないという問題がある。さらに，上記ホル
ダの線膨張係数が５×１０-6／℃未満の場合には，試験
片とホルダの形状・寸法を調整しても全ひずみ範囲が大
きくなりすぎて寿命が１００サイクル未満になる場合が
多いという問題がある。一方，１８×１０-6／℃を超え
る場合には，試験片とホルダの形状・寸法を調整しても
全ひずみ範囲が小さくなりすぎて寿命が１００００サイ
クルを超える場合が多いという問題がある。The room temperature hardness of the holder is HV300.
If it is less than the above, there is a problem that the holder cannot sufficiently obtain the restraint force of the thermal fatigue test piece. Furthermore, if the coefficient of linear expansion of the holder is less than 5 × 10 -6 / ° C, the total strain range will be too large and the life will be less than 100 cycles even if the shape and dimensions of the test piece and the holder are adjusted. The problem is that there are many cases. On the other hand, if it exceeds 18 × 10 −6 / ° C., the total strain range becomes too small even if the shapes and dimensions of the test piece and the holder are adjusted, and the service life often exceeds 10,000 cycles.
【００２４】また，上記ホルダの材質は，Ｆｅ基γ’析
出強化型合金，析出強化型ステンレス鋼，熱間金型用
鋼，Ｎｉ基γ’析出強化型合金のいずれかであることが
好ましい（請求項５）。これらの材料を採用することに
よって，上記の温度特異点が存在しない低膨張材料であ
るという特性を有するホルダを容易に得ることができ
る。The material of the holder is preferably any one of Fe-based γ'precipitation strengthened alloy, precipitation-strengthened stainless steel, hot die steel, and Ni-based γ'precipitation-strengthened alloy ( Claim 5). By adopting these materials, it is possible to easily obtain a holder having the characteristic of being a low expansion material having no temperature singularity.
【００２５】次に，第２の発明（請求項６）において
も，第１の発明と同様に，上記熱疲労試験片は，ピスト
ン用アルミ合金よりなり，上記試験温度範囲の上限温度
が３００℃以上であり，上記ホルダの室温硬さがＨＶ３
００以上であり，上記ホルダの線膨張係数が５〜１８×
１０-6／℃であることが好ましい（請求項８）。さら
に，上記ホルダの材質は，Ｆｅ基γ’析出強化型合金，
析出強化型ステンレス鋼，熱間金型用鋼，Ｎｉ基γ’析
出強化型合金のいずれかであることが好ましい（請求項
９）。In the second invention (Claim 6), as in the first invention, the thermal fatigue test piece is made of an aluminum alloy for pistons, and the upper limit temperature of the test temperature range is 300 ° C. Above, the room temperature hardness of the holder is HV3
00 or more, and the linear expansion coefficient of the holder is 5 to 18 ×
It is preferably 10 −6 / ° C. (claim 8). Further, the material of the holder is Fe-based γ'precipitation strengthened alloy,
It is preferably any one of precipitation-strengthened stainless steel, hot die steel, and Ni-based γ'precipitation-strengthened alloy (claim 9).
【００２６】[0026]
【実施例】本発明の実施例に係る熱疲労試験方法及び熱
疲労試験装置につき，図１〜図６を用いて説明する。本
例の熱疲労試験方法においては，図１に示すごとく，中
央部に両端部よりも断面積が小さな評価部分１０を有す
る棒状の熱疲労試験片１を用意する。また，図２に示す
ごとく，試験温度範囲において上記熱疲労試験片１より
熱膨張係数が小さく，かつ熱膨張係数が急激に変化する
温度特異点が存在しない低膨張材料からなり，上記熱疲
労試験片１の両端部１１と接触する両側の固定端部２１
に複数のＶ字形の刃２２を設けた２枚のホルダ２を用意
する。EXAMPLE A thermal fatigue test method and a thermal fatigue test apparatus according to an example of the present invention will be described with reference to FIGS. In the thermal fatigue test method of this example, as shown in FIG. 1, a rod-shaped thermal fatigue test piece 1 having an evaluation portion 10 having a smaller cross-sectional area than both ends in the central portion is prepared. As shown in FIG. 2, the thermal fatigue test piece 1 has a smaller thermal expansion coefficient than the thermal fatigue test piece 1 and is made of a low expansion material having no temperature singularity at which the thermal expansion coefficient rapidly changes. Fixed ends 21 on both sides in contact with both ends 11 of the piece 1
Two holders 2 provided with a plurality of V-shaped blades 22 are prepared.
【００２７】そして，図３に示すごとく，上記熱疲労試
験片１をその両側から上記ホルダ２によって挟持するよ
うに拘束するに際し，上記ホルダ２の上記刃２２を上記
熱疲労試験片１の両端部１１に圧入するとともに，上記
熱疲労試験片１の両端部１１と上記ホルダ２の上記固定
端部２１との間の結合の緩みを防止するために弾性部材
３１を介して結合手段３によって上記熱疲労試験片１の
両端部１１と上記ホルダ２の上記固定端部２１とを拘束
する。Then, as shown in FIG. 3, when the thermal fatigue test piece 1 is constrained so as to be sandwiched by the holders 2 from both sides thereof, the blades 22 of the holder 2 are held at both ends of the thermal fatigue test piece 1. 11 by press-fitting the heat-fatigue test piece 1 through the elastic member 31 so as to prevent loosening of the connection between the both ends 11 of the thermal fatigue test piece 1 and the fixed end 21 of the holder 2. Both ends 11 of the fatigue test piece 1 and the fixed end 21 of the holder 2 are constrained.
【００２８】また，上記熱疲労試験片１の上記評価部分
１０には熱ひずみを測定するための歪みゲージ５９を配
置する。そして，この拘束状態のまま上記熱疲労試験片
１および上記ホルダ２の全体に対して加熱・冷却サイク
ルを繰り返し行うと共に，上記熱疲労試験片１の両端部
１１と上記ホルダ２の固定端部２１との間の結合力が低
下することを抑制するための上記結合手段の増し締めを
少なくとも試験中に１回行う。A strain gauge 59 for measuring thermal strain is arranged in the evaluation portion 10 of the thermal fatigue test piece 1. The heating / cooling cycle is repeated for the entire thermal fatigue test piece 1 and the holder 2 in this restrained state, and both end portions 11 of the thermal fatigue test piece 1 and the fixed end portions 21 of the holder 2 are repeated. Reinforcement of the coupling means is carried out at least once during the test in order to suppress the reduction of the coupling force between and.
【００２９】そして，上記熱疲労試験片１と上記ホルダ
２との熱膨張差により生じる熱ひずみを上記熱疲労試験
片１の上記評価部分１０に局所的に集中させ，上記熱疲
労試験片１が破断した際の上記加熱・冷却サイクルのサ
イクル数により熱疲労寿命を求めると共に，上記歪みゲ
ージにより全ひずみ範囲を求める。Then, the thermal strain caused by the difference in thermal expansion between the thermal fatigue test piece 1 and the holder 2 is locally concentrated on the evaluation portion 10 of the thermal fatigue test piece 1 so that the thermal fatigue test piece 1 is The thermal fatigue life is obtained from the number of heating / cooling cycles at the time of fracture, and the total strain range is obtained from the strain gauge.
【００３０】以下，これを詳説する。図１に熱疲労試験
片１の寸法・形状を示す。本例の熱疲労試験片１の材質
はピストンに多用されているＪＩＳ−ＡＣ８Ａ合金の熱
処理（Ｔ６処理）材である。熱疲労試験片１のサイズと
しては大型，中型，小型の３種類を準備した。具体的に
は，表１に示すごとく，図１中の寸法Ｌ１，Ｌ２，ｔ寸
法を変化させている。This will be described in detail below. FIG. 1 shows the dimensions and shape of the thermal fatigue test piece 1. The material of the thermal fatigue test piece 1 of this example is a heat-treated (T6 treated) material of JIS-AC8A alloy which is often used for pistons. As the size of the thermal fatigue test piece 1, three types of large, medium and small were prepared. Specifically, as shown in Table 1, the dimensions L1, L2 and t in FIG. 1 are changed.
【００３１】[0031]
【表１】 [Table 1]
【００３２】いずれの熱疲労試験片１も，中央に両端部
１１よりも断面積が小さな平行部よりなる評価部分１０
を有する。平行部はφ４ｍｍ×長さＡが６ｍｍの円柱状
である。両端部１１は幅Ｂが１０ｍｍの直方体に挿入穴
１１５のあいた形状で，両側からホルダ２の刃を圧入可
能な平坦部１１２を有する。In each of the thermal fatigue test pieces 1, an evaluation portion 10 consisting of a parallel portion having a cross-sectional area smaller than that of the both end portions 11 at the center.
Have. The parallel portion is a cylinder having a diameter of 4 mm and a length A of 6 mm. Both end portions 11 have a shape of a rectangular parallelepiped having a width B of 10 mm with an insertion hole 115, and have flat portions 112 into which the blades of the holder 2 can be pressed.
【００３３】図２に熱疲労試験片を拘束するホルダ２の
寸法・形状を示す。ホルダ２のサイズとしては，大型，
中型，小型の３種類を準備した。具体的には，表２に示
すごとく，図２中のＬ０，Ｌ２，Ｌ３寸法を変化させて
いる。ホルダ２の固定端部２１には角度αが６０℃，ピ
ッチ０．３ｍｍの先端が鋭角なＶ字形の刃２２が設けて
あると共に，挿入穴２１５を設けてある。また，ホルダ
２の幅Ｃは６ｍｍ，厚みＤは４ｍｍである。FIG. 2 shows the size and shape of the holder 2 for restraining the thermal fatigue test piece. The holder 2 has a large size,
We prepared three types, medium and small. Specifically, as shown in Table 2, the L0, L2, and L3 dimensions in FIG. 2 are changed. The fixed end portion 21 of the holder 2 is provided with a V-shaped blade 22 having an angle α of 60 ° C. and a pitch of 0.3 mm and an acute tip, and an insertion hole 215. The width C of the holder 2 is 6 mm and the thickness D is 4 mm.
【００３４】[0034]
【表２】 [Table 2]
【００３５】これらの熱疲労試験片１とホルダ２は，そ
れぞれ大型同士，中型同士あるいは小型同士で組み合わ
せで使用する。The thermal fatigue test pieces 1 and the holder 2 are used in combination of large size, medium size or small size.
【００３６】ホルダ２の材質としては，本例ではIncolo
y９０３合金（商品名ＨＲＡ９０３，日立金属社製）
と，ＳＵＳ６３０合金の２種類の合金を採用した。これ
らの合金の室温から３００℃間の平均熱膨張係数は，In
coloy９０３合金は７．７×１０-6／℃，ＳＵＳ６３０
合金は１１．３×１０-6／℃であり，いずれもＡＣ８Ａ
合金に比べて低い。また，いずれもの合金も，少なくと
も上限３５０℃までの温度範囲では磁気変態を生じず，
安定した低熱膨張を示す。また，室温における硬さは，
溶体化処理＋時効処理により，Incoloy９０３合金はＨ
Ｖ３７０，ＳＵＳ６３０合金はＨＶ３９０に高めた。The material of the holder 2 is Incolo in this example.
y903 alloy (brand name HRA903, made by Hitachi Metals)
, And two types of alloys, SUS630 alloy, were adopted. The average coefficient of thermal expansion of these alloys between room temperature and 300 ° C is
coloy903 alloy is 7.7 × 10 -6 / ° C, SUS630
The alloy is 11.3 × 10 -6 / ° C, both AC8A
Lower than alloys. In addition, in all alloys, magnetic transformation does not occur at least in the temperature range up to 350 ° C,
It shows stable low thermal expansion. The hardness at room temperature is
Incoloy 903 alloy becomes H by solution treatment + aging treatment.
The V370 and SUS630 alloys have been upgraded to HV390.
【００３７】なお，上記ホルダ２の材質として採用可能
な他の材料としては，室温硬さがＨＶ３００以上，線熱
膨張係数が５〜１８×１０-6／℃のＦｅ基γ’析出強化
型合金，析出強化型ステンレス鋼，熱間金型用鋼，Ｎｉ
基γ’析出強化型銅などがある。Other materials that can be used as the material of the holder 2 include Fe-based γ'precipitation strengthened alloys having a room temperature hardness of HV300 or more and a linear thermal expansion coefficient of 5 to 18 × 10 -6 / ° C. , Precipitation strengthened stainless steel, hot die steel, Ni
Base γ'precipitation strengthened copper and the like.
【００３８】参考のため，図４にホルダ用候補材料と代
表的なピストン用アルミ合金ＡＣ８Ａの熱膨張曲線を示
す。同図は横軸に温度，縦軸に熱膨張量をとったもので
ある。同図からIncoloy９０４合金（商品名ＨＲＡ９０
４，日立金属社製）は約３００℃までは熱膨張が小さい
が，それ以上の温度域では熱膨張係数が急激に大きくな
る。本熱疲労試験法ではホルダと熱疲労試験片の熱膨張
差が熱疲労試験片に熱ひずみを生じさせる駆動力になる
ので，このような熱膨張係数の温度依存性が大きな材質
のホルダを用いると熱疲労試験片に生じる熱ひずみにも
温度依存性が現れるので好ましくない。For reference, FIG. 4 shows thermal expansion curves of the holder candidate material and a typical piston aluminum alloy AC8A. In the figure, the horizontal axis represents temperature and the vertical axis represents the amount of thermal expansion. From the figure, Incoloy 904 alloy (trade name HRA90
4, Hitachi Metals Co., Ltd.) has a small thermal expansion up to about 300 ° C., but the coefficient of thermal expansion rapidly increases in the temperature range higher than that. In this thermal fatigue test method, the difference in thermal expansion between the holder and the thermal fatigue test piece is the driving force that causes thermal strain in the thermal fatigue test piece, so a holder made of a material whose temperature coefficient of thermal expansion is large is used. Also, the temperature dependence appears in the thermal strain generated in the thermal fatigue test piece, which is not preferable.
【００３９】また，熱膨張係数が急激に変化する磁気変
態温度は合金組成によって変化し，この温度の違いが試
験温度範囲におけるホルダと熱疲労試験片の熱膨張差に
影響し，それに伴い熱疲労試験片に生じる熱ひずみの大
きさも変化するので，このような合金はホルダ材として
好ましくない。従って，図４からは，Incoloy９０４の
ような温度依存性がほとんどない，Incoloy９０３およ
びＳＫＤ６１がホルダ２の材質として適していることが
わかる。The magnetic transformation temperature at which the coefficient of thermal expansion changes abruptly depends on the alloy composition, and this difference in temperature affects the difference in thermal expansion between the holder and the thermal fatigue test piece in the test temperature range, which causes thermal fatigue. Such an alloy is not suitable as a holder material because the magnitude of thermal strain generated in the test piece also changes. Therefore, it can be seen from FIG. 4 that the Incoloy 903 and the SKD 61, which have almost no temperature dependency like the Incoloy 904, are suitable as the material of the holder 2.
【００４０】また，低熱膨張合金としてよく知られるも
のとして，アンバー合金があるが，同合金は磁気変態温
が低く上記の様に熱膨張係数の温度依存性が大きいのに
加え，一般的には硬さが低いので，ホルダ材として熱疲
労試験片を後述するように組み付けた場合，ホルダの刃
の先端が変形し鋭角さが失われ，これにより熱疲労試験
片を十分に拘束することができなくなるため，やはりホ
ルダ材としては好ましくない。Further, as a well-known low thermal expansion alloy, there is an amber alloy, which has a low magnetic transformation temperature and a large temperature dependence of the thermal expansion coefficient as described above. Since the hardness is low, when a thermal fatigue test piece is assembled as a holder material as described later, the tip of the blade of the holder is deformed and the sharp angle is lost, which allows the thermal fatigue test piece to be sufficiently restrained. Since it disappears, it is not preferable as a holder material.
【００４１】上記のごとく，本例の熱疲労試験に用いる
ホルダ２の材質は，十分な硬さと安定した低熱膨張特性
を併せ持つことが必要である。そして，ホルダ２の硬さ
としては，ＨＶ３００以上であることが好ましい。ま
た，その熱膨張係数としては，試験温度全域において，
１２×１０-6／℃以下であることが好ましい。As described above, the material of the holder 2 used in the thermal fatigue test of this example must have both sufficient hardness and stable low thermal expansion characteristics. The hardness of the holder 2 is preferably HV300 or higher. The coefficient of thermal expansion is
It is preferably 12 × 10 −6 / ° C. or less.
【００４２】次に，本例において使用する熱疲労試験装
置５につき簡単に説明する。本例の熱疲労試験装置５
は，図５に示すごとく，上記熱疲労試験片１を拘束する
上記の２枚のホルダ２と，これら全体に対して加熱・冷
却サイクルを繰り返し行うための加熱手段及び冷却手段
を兼ね備えた加熱冷却装置５１と，上記熱疲労試験片１
の上記評価部分１０の熱ひずみを測定するための歪みゲ
ージ５９とを有している。Next, the thermal fatigue test apparatus 5 used in this example will be briefly described. Thermal fatigue test apparatus 5 of this example
As shown in FIG. 5, the above-mentioned two holders 2 for restraining the thermal fatigue test piece 1 and heating / cooling having both heating means and cooling means for repeatedly performing heating / cooling cycles on the whole holders. Device 51 and the above thermal fatigue test piece 1
And a strain gauge 59 for measuring the thermal strain of the evaluation portion 10.
【００４３】上記加熱冷却装置５１は，同図に示すごと
く，上記熱疲労試験片１を左右前後の４方向から挟持す
るように対向して配設された２種類のエアダクト５２，
５３を有している。第１のエアダクト５２は，熱疲労試
験片１を挟んで２本ずつ配置されている。また，第２の
エアダクト５３は，上記第１のエアダクト５２と略直角
に交差する位置において対向するように，熱疲労試験片
１を挟んで１本ずつ配置されている。As shown in the figure, the heating / cooling device 51 includes two types of air ducts 52, which are arranged so as to face each other so as to sandwich the thermal fatigue test piece 1 from the left, right, front and rear directions.
It has 53. Two first air ducts 52 are arranged with the thermal fatigue test piece 1 interposed therebetween. Further, the second air ducts 53 are arranged one by one with the thermal fatigue test piece 1 sandwiched therebetween so as to face each other at a position intersecting the first air duct 52 at a substantially right angle.
【００４４】第１のエアダクト５２は，いずれもまっす
ぐな円筒状の管より構成され，その内部には，導入され
た圧縮空気を加熱するための電気ヒータ５２５を有して
いる。第２のエアダクト５３は，それぞれ開口部を扇状
に上下に拡大させた管により構成され，その内部には，
導入された圧縮空気を加熱するための電気ヒータ５３５
を有している。Each of the first air ducts 52 is composed of a straight cylindrical tube, and has an electric heater 525 for heating the introduced compressed air therein. Each of the second air ducts 53 is composed of a tube whose opening is vertically expanded in a fan shape, and inside thereof,
Electric heater 535 for heating the introduced compressed air
have.
【００４５】そして，上記加熱冷却装置５１は，上記熱
疲労試験片１を加熱する際には，各エアダクト５２，５
３に導入された圧縮空気を所望温度に加熱することによ
り熱風を吐出してこれを上記熱疲労試験片１に当てるこ
とができるよう構成されている。また，上記熱疲労試験
片１を冷却する際には，各エアダクト５２，５３に導入
された圧縮空気を加熱することなく吐出してこれを熱疲
労試験片１に当てることができるよう構成されている。The heating / cooling device 51, when heating the thermal fatigue test piece 1, heats the air ducts 52, 5
By heating the compressed air introduced into No. 3 to a desired temperature, hot air is discharged and this can be applied to the thermal fatigue test piece 1. Further, when the thermal fatigue test piece 1 is cooled, the compressed air introduced into each of the air ducts 52 and 53 is discharged without being heated so that the compressed air can be applied to the thermal fatigue test piece 1. There is.
【００４６】また，本例では，図３に示すごとく，上記
熱疲労試験片１をホルダ２により拘束する際の結合手段
３としては，ボルト３０１，ナット３０２を，上記弾性
部材３１としては，皿バネを用いた。また，皿バネ３１
とホルダ２との間には，ワッシャー３９を介在させた。Further, in this example, as shown in FIG. 3, a bolt 301 and a nut 302 are used as the connecting means 3 when the thermal fatigue test piece 1 is restrained by the holder 2, and a dish is used as the elastic member 31. A spring was used. Also, the disc spring 31
A washer 39 was interposed between the holder and the holder 2.
【００４７】そして，同図に示すごとく，熱疲労試験片
１を２枚のホルダ２で挟み，ホルダ２の刃２２を熱疲労
試験片１の両側部１１に圧入した後，ワッシャー３９，
皿バネ３１を介してボルト３０１，ナット３０２を用い
て熱疲労試験片１とホルダ２を一体化した。圧入荷重は
４．８ｔ，ボルト３０１，ナット３０２の締め付けトル
クは６０ｋｇｆ・ｃｍとした。Then, as shown in the figure, the thermal fatigue test piece 1 is sandwiched between two holders 2, and the blades 22 of the holder 2 are press-fitted into both side portions 11 of the thermal fatigue test piece 1, and then the washer 39,
The thermal fatigue test piece 1 and the holder 2 were integrated by using the bolt 301 and the nut 302 via the disc spring 31. The press-fitting load was 4.8 t, and the tightening torque for the bolt 301 and the nut 302 was 60 kgf · cm.
【００４８】本例では，大型の熱疲労試験片１に対して
Incoloy９０３よりなる大型のホルダ２を用いた試験
（試験１），中型の熱疲労試験片１に対してIncoloy９
０３よりなる中型のホルダ２を用いた試験（試験２），
中型の熱疲労試験片１に対してＳＵＳ６３０よりなる中
型のホルダ２を用いた試験（試験３），小型の熱疲労試
験片１に対してIncoloy９０３よりなる小型のホルダ２
を用いた試験（試験４）という４種類の試験を実施し
た。In this example, for a large thermal fatigue test piece 1,
Test using a large holder 2 made of Incoloy 903 (Test 1), Incoloy 9 for medium-sized thermal fatigue test piece 1
Test using a medium-sized holder 2 made of 03 (Test 2),
Test using medium-sized holder 2 made of SUS630 for medium-sized thermal fatigue test piece 1 (test 3), small holder 2 made of Incoloy 903 for small thermal fatigue test piece 1
Four types of tests, that is, a test using (Test 4) were carried out.
【００４９】いずれの試験においても，上記のごとく拘
束した熱疲労試験片１をホルダ２と共に，加熱冷却装置
５１を用いて，均一に加熱・冷却した。１サイクル中の
加熱時間，冷却時間は共に２ｍｉｎとした。この時，熱
疲労試験片１の中央部の表面の温度範囲が５０〜３５０
℃になる様，エア温度を制御した。In each test, the thermal fatigue test piece 1 constrained as described above was uniformly heated and cooled together with the holder 2 using the heating / cooling device 51. The heating time and the cooling time in one cycle were both 2 min. At this time, the temperature range of the surface of the central portion of the thermal fatigue test piece 1 was 50 to 350.
The air temperature was controlled so that it reached ℃.
【００５０】また本例では，試験中の加熱によって熱疲
労試験片１が軟化し両端の拘束部に変形が生じた。これ
に伴うボルト・ナットの締め付けトルク低下を抑制する
ため，１００，５００，１０００サイクルとその後１０
００サイクル毎にボルト・ナットの増し締めを行った。
増し締め時のトルクは６０ｋｇｆ・ｃｍである。Further, in this example, the thermal fatigue test piece 1 was softened by the heating during the test and the restraint portions at both ends were deformed. In order to suppress the decrease in tightening torque of bolts and nuts that accompanies this, 100, 500, 1000 cycles and then 10
The bolts and nuts were retightened every 00 cycles.
The torque during retightening is 60 kgf · cm.
【００５１】図６にIncoloy９０３製中型ホルダとＡＣ
８Ａ合金よりなる中型の熱疲労試験片１との組み合わせ
（試験２）について，上記の条件で熱疲労試験を行った
際の全ひずみ範囲の変化を示す。同図は，横軸に加熱・
冷却のサイクル数を，縦軸に全ひずみ範囲をとったもの
である。なお，ひずみは高温用ひずみゲージを用いて実
測した。FIG. 6 shows a medium-sized holder made of Incoloy 903 and an AC.
The change of the total strain range at the time of performing a thermal fatigue test on the above-mentioned conditions about the combination (test 2) with the medium-sized thermal fatigue test piece 1 which consists of 8A alloy is shown. This figure shows the heating on the horizontal axis.
The cooling cycle number is the total strain range on the vertical axis. The strain was measured using a high temperature strain gauge.
【００５２】同図に実線ａで示す様に，全ひずみ範囲は
試験サイクル数の増加に伴い低下する。途中サイクルに
てホルダ２と熱疲労試験片１を締結しているボルト・ナ
ットの増し締めを行わないと，波線ｂで示すように，全
ひずみ範囲の低下がさらに進行し，熱疲労試験片１に亀
裂が生じないおそれがある。As shown by the solid line a in the figure, the total strain range decreases as the number of test cycles increases. Unless the bolts and nuts that fasten the holder 2 and the thermal fatigue test piece 1 in the intermediate cycle are retightened, the total strain range further decreases as indicated by the wavy line b, and the thermal fatigue test piece 1 It may not crack.
【００５３】本例では途中サイクルに増し締めを行うこ
とにより，実線ａで示すように，全ひずみ範囲が回復
し，熱疲労試験片１に亀裂が生じて熱疲労寿命を求める
ことができた。このように全ひずみ範囲が低下するの
は，試験上限温度が３００℃以上と高く，熱疲労試験片
１の軟化が著しいため，熱疲労試験片１の両端部１１が
変形してホルダ２による拘束が緩むためと考えられる。
したがって，材料の軟化が極めて著しい，上限３００℃
以上というピストン用アルミ合金の使用環境を想定して
限定された試験条件下において熱疲労特性を評価するた
めには，試験途中に拘束の緩みを防止するための増し締
めを行わなければならないことがわかった。In this example, by performing the additional tightening in the middle cycle, as shown by the solid line a, the entire strain range was recovered and cracks were generated in the thermal fatigue test piece 1 so that the thermal fatigue life could be obtained. The reason why the total strain range decreases in this way is that the test upper limit temperature is as high as 300 ° C. or higher and the softening of the thermal fatigue test piece 1 is remarkable, so that both ends 11 of the thermal fatigue test piece 1 are deformed and restrained by the holder 2. Is thought to be loosening.
Therefore, the softening of the material is extremely remarkable and the upper limit is 300 ° C.
In order to evaluate the thermal fatigue properties under the limited test conditions assuming the above-mentioned usage environment of the aluminum alloy for pistons, it is necessary to perform additional tightening to prevent loosening of constraints during the test. all right.
【００５４】各試験１〜４の結果を表３に示す。表３に
は，高温ひずみゲージで実測した熱疲労試験片平行部の
全ひずみ範囲と上記試験によって求めた熱疲労寿命を記
載する。なお，全ひずみ範囲としては１００サイクルま
での平均値を示した。亀裂が生じると短いサイクル数の
間に急激に進展して破断に至った。熱疲労寿命は熱疲労
試験片平行部の全周に亀裂が進展したサイクル数と定義
した。The results of tests 1 to 4 are shown in Table 3. Table 3 shows the total strain range of the parallel part of the thermal fatigue test piece measured by the high temperature strain gauge and the thermal fatigue life obtained by the above test. The total strain range is an average value up to 100 cycles. When a crack occurred, it rapidly progressed during a short number of cycles, leading to fracture. The thermal fatigue life was defined as the number of cycles in which a crack propagated all around the parallel part of the thermal fatigue test piece.
【００５５】[0055]
【表３】 [Table 3]
【００５６】同表に示す通り，いずれの試験において
も，上記熱疲労試験片とホルダの組み合わせにより，上
限３５０℃というピストン用アルミ合金の使用温度を想
定した環境において，寿命が１００〜１００００サイク
ルという実用域での熱疲労特性を評価することができ
た。As shown in the table, in any of the tests, the life was 100 to 10000 cycles in the environment in which the upper limit of 350 ° C. was used for the aluminum alloy for pistons by the combination of the thermal fatigue test piece and the holder. It was possible to evaluate the thermal fatigue characteristics in the practical range.
【００５７】なお，本試験における全ひずみ範囲は０．
４〜０．９％の範囲内にあった。以上の結果から，本発
明の熱疲労試験法によりピストン用アルミ合金の熱疲労
特性を評価できることが検証された。この結果から，本
例の熱疲労試験方法及び熱疲労試験装置５を用いて，他
の材質の熱疲労試験片，例えばＡＣ８Ａ−Ｔ６の改良合
金等の熱疲労試験を上記と同様に行うことによって，そ
の合金がＡＣ８Ａ−Ｔ６に比べて熱疲労特性が向上した
か否か等の評価を簡単に行うことができる。The total strain range in this test is 0.
It was in the range of 4 to 0.9%. From the above results, it was verified that the thermal fatigue characteristics of the aluminum alloy for pistons can be evaluated by the thermal fatigue test method of the present invention. From this result, by using the thermal fatigue test method and the thermal fatigue test apparatus 5 of the present example, a thermal fatigue test piece of another material, for example, an improved alloy of AC8A-T6, etc., was subjected to the same thermal fatigue test as above. It is possible to easily evaluate whether the alloy has improved thermal fatigue properties as compared with AC8A-T6.
【図１】実施例における，熱疲労試験片の形状及び寸法
を示す，（ａ）平面図，（ｂ）正面図。FIG. 1A is a plan view and FIG. 1B is a front view showing the shape and dimensions of a thermal fatigue test piece in Examples.
【図２】実施例における，ホルダの形状及び寸法を示
す，（ａ）正面図，（ｂ）側面図，（ｃ）刃部分の拡大
説明図。FIG. 2A is a front view, FIG. 2B is a side view, and FIG. 2C is an enlarged explanatory view of a blade portion, showing the shape and dimensions of the holder in the embodiment.
【図３】実施例における，熱疲労試験片とホルダとの拘
束状態を示す，（ａ）平面図，（ｂ）正面図。FIG. 3A is a plan view and FIG. 3B is a front view showing a restrained state between a thermal fatigue test piece and a holder in an example.
【図４】実施例における，ホルダ候補材質の熱膨張量の
温度依存性を示す説明図。FIG. 4 is an explanatory view showing the temperature dependence of the thermal expansion amount of the holder candidate material in the example.
【図５】実施例における，熱疲労試験装置の構成を示す
説明図。FIG. 5 is an explanatory diagram showing a configuration of a thermal fatigue testing device in an example.
【図６】実施例における，サイクル数と全ひずみ範囲の
関係を示す説明図。FIG. 6 is an explanatory diagram showing the relationship between the number of cycles and the total strain range in the example.
１．．．熱疲労試験片， １０．．．評価部分， １１．．．両端部， １１５．．．挿入穴， ２．．．ホルダ， ２１．．．固定端部， ２１５．．．挿入穴， ２２．．．刃， ３．．．結合手段， ３０１．．．ボルト， ３０２．．．ナット， ３１．．．弾性部材（皿バネ）， 1. ． ． Thermal fatigue test piece, 10. ． ． Evaluation part, 11. ． ． Both ends, 115. ． ． Insertion hole, 2. ． ． holder, 21. ． ． Fixed end, 215. ． ． Insertion hole, 22. ． ． blade, 3. ． ． Coupling means, 301. ． ． bolt, 302. ． ． nut, 31. ． ． Elastic member (disc spring),
Claims (9)
価部分を有する棒状の熱疲労試験片と，試験温度範囲に
おいて上記熱疲労試験片より熱膨張係数が小さく，かつ
熱膨張係数が急激に変化する温度特異点が存在しない低
膨張材料からなり，上記熱疲労試験片の両端部と接触す
る両側の固定端部に複数のＶ字形の刃を設けた２枚のホ
ルダとを用意し，上記熱疲労試験片をその両側から上記
ホルダによって挟持するように拘束するに際し，上記ホ
ルダの上記刃を上記熱疲労試験片の両端部に圧入すると
ともに，上記熱疲労試験片の両端部と上記ホルダの上記
固定端部との間の結合の緩みを防止するために弾性部材
を介して結合手段によって上記熱疲労試験片の両端部と
上記ホルダの上記固定端部とを拘束し，この拘束状態の
まま上記熱疲労試験片および上記ホルダの全体に対して
加熱・冷却サイクルを繰り返し行うと共に，上記熱疲労
試験片の両端部と上記ホルダの固定端部との間の結合力
が低下することを抑制するための上記結合手段の増し締
めを少なくとも試験中に１回行い，上記熱疲労試験片と
上記ホルダとの熱膨張差により生じる熱ひずみを上記熱
疲労試験片の上記評価部分に局所的に集中させ，上記熱
疲労試験片が破断した際の上記加熱・冷却サイクルのサ
イクル数により熱疲労寿命を求めることを特徴とする熱
疲労試験方法。1. A rod-shaped thermal fatigue test piece having an evaluation portion having a smaller cross-sectional area than both ends in the center, and a thermal expansion coefficient smaller than that of the above thermal fatigue test piece in the test temperature range and a rapid thermal expansion coefficient. Prepared are two holders made of a low expansion material having no temperature singularity that changes, and having a plurality of V-shaped blades at the fixed ends on both sides in contact with both ends of the thermal fatigue test piece, When restraining the thermal fatigue test piece from both sides so as to be sandwiched by the holder, the blades of the holder are press-fitted into both ends of the thermal fatigue test piece, and both ends of the thermal fatigue test piece and the holder are pressed. In order to prevent the looseness of the connection with the fixed end of the holder, both ends of the thermal fatigue test piece and the fixed end of the holder are restrained by elastic means through an elastic member, The above thermal fatigue test The heating / cooling cycle is repeated for the entire piece and the holder, and at the same time, the above-mentioned coupling for suppressing a decrease in the coupling force between the both ends of the thermal fatigue test piece and the fixed end of the holder. The means is retightened at least once during the test, and the thermal strain caused by the difference in thermal expansion between the thermal fatigue test piece and the holder is locally concentrated on the evaluation portion of the thermal fatigue test piece to perform the thermal fatigue test. A thermal fatigue test method characterized in that the thermal fatigue life is obtained by the number of cycles of the heating / cooling cycle when a test piece breaks.
上記評価部分には熱ひずみを測定するための歪みゲージ
を配置し，上記加熱・冷却サイクルの繰り返し時に上記
歪みゲージにより全ひずみ範囲を求めることを特徴とす
る熱疲労試験方法。2. The strain gauge for measuring thermal strain is arranged at the evaluation portion of the thermal fatigue test piece according to claim 1, and when the heating / cooling cycle is repeated, the entire strain range is measured by the strain gauge. A thermal fatigue test method characterized by obtaining.
び上記ホルダは，上記試験温度範囲において上記熱疲労
試験片の上記評価部分に生じる全ひずみ範囲が０．２〜
２％であり，上記熱疲労寿命が１００〜１００００サイ
クルとなる様な形状及び寸法を有するものを用いること
を特徴とする熱疲労試験方法。3. The thermal fatigue test piece and the holder according to claim 1, wherein a total strain range generated in the evaluation portion of the thermal fatigue test piece is 0.2 to 10 in the test temperature range.
The thermal fatigue test method is characterized by using a material having a shape and dimensions such that the thermal fatigue life is 100% to 10000 cycles, which is 2%.
験片は，ピストン用アルミ合金よりなり，上記試験温度
範囲の上限温度が３００℃以上であり，上記ホルダの室
温硬さがＨＶ３００以上であり，上記ホルダの線膨張係
数が５〜１８×１０-6／℃であることを特徴とする熱疲
労試験方法。4. The thermal fatigue test piece according to claim 1, wherein the test piece is made of an aluminum alloy for pistons, the upper limit temperature of the test temperature range is 300 ° C. or higher, and the room temperature hardness of the holder is HV300 or higher. A thermal fatigue test method, wherein the holder has a linear expansion coefficient of 5 to 18 × 10 −6 / ° C.
は，Ｆｅ基γ’析出強化型合金，析出強化型ステンレス
鋼，熱間金型用鋼，Ｎｉ基γ’析出強化型合金のいずれ
かであることを特徴とする熱疲労試験方法。5. The material of the holder according to claim 4, wherein the material is Fe-based γ'precipitation-strengthened alloy, precipitation-strengthened stainless steel, hot die steel, or Ni-based γ'precipitation-strengthened alloy. A thermal fatigue test method characterized by being present.
価部分を有する棒状の熱疲労試験片の熱疲労試験を行う
装置であって，試験温度範囲において上記熱疲労試験片
より熱膨張係数が小さく，かつ熱膨張係数が急激に変化
する温度特異点が存在しない低膨張材料からなり，上記
熱疲労試験片の両端部と接触する両側の固定端部に複数
のＶ字形の刃を設けた２枚のホルダと，上記熱疲労試験
片の両側から上記ホルダによって挟持するように拘束す
るに際し，上記ホルダの上記刃を上記熱疲労試験片の両
端部に圧入するとともに，上記熱疲労試験片の両端部と
上記ホルダの上記固定端部との間の結合の緩みを防止す
るために弾性部材を介して結合手段によって上記熱疲労
試験片の両端部と上記ホルダの上記固定端部とを拘束し
た状態で上記熱疲労試験片および上記ホルダの全体に対
して加熱・冷却サイクルを繰り返し行うための加熱手段
及び冷却手段とを有していることを特徴とする熱疲労試
験装置。6. An apparatus for performing a thermal fatigue test of a rod-shaped thermal fatigue test piece having an evaluation portion having a smaller cross-sectional area than both ends in a central portion, the thermal expansion coefficient being higher than that of the thermal fatigue test piece in a test temperature range. Is made of a low-expansion material that has a small thermal expansion coefficient and does not have a temperature singularity at which the coefficient of thermal expansion changes rapidly, and a plurality of V-shaped blades are provided at the fixed ends on both sides in contact with both ends of the thermal fatigue test piece. When restraining the two holders so that they are sandwiched by the holder from both sides of the thermal fatigue test piece, the blades of the holder are pressed into both ends of the thermal fatigue test piece, and Both ends of the thermal fatigue test piece and the fixed end of the holder were restrained by a connecting means via elastic members in order to prevent loosening of the connection between the both ends and the fixed end of the holder. The above thermal fatigue in the state A thermal fatigue test apparatus comprising: a heating unit and a cooling unit for repeatedly performing a heating / cooling cycle on the entire test piece and the holder.
試験片の上記評価部分の熱ひずみを測定するための歪み
ゲージを有していることを特徴とする熱疲労試験装置。7. The thermal fatigue test apparatus according to claim 6, further comprising a strain gauge for measuring thermal strain of the evaluation portion of the thermal fatigue test piece.
は，ピストン用アルミ合金よりなり，上記試験温度範囲
の上限温度が３００℃以上であり，上記ホルダの室温硬
さがＨＶ３００以上であり，上記ホルダの線膨張係数が
５〜１８×１０ -6／℃であることを特徴とする熱疲労試
験装置。8. The thermal fatigue test piece according to claim 6.
Is made of aluminum alloy for pistons and has the above test temperature range.
Has an upper limit temperature of 300 ° C or higher,
Is HV300 or more, and the linear expansion coefficient of the holder is
5-18 × 10 -6/ ° C, thermal fatigue test characterized by
Test equipment.
は，Ｆｅ基γ’析出強化型合金，析出強化型ステンレス
鋼，熱間金型用鋼，Ｎｉ基γ’析出強化型合金のいずれ
かであることを特徴とする熱疲労試験装置。9. The material of the holder according to claim 8, wherein the material is Fe-based γ'precipitation strengthened alloy, precipitation-strengthened stainless steel, hot die steel, or Ni-based γ'precipitation strengthened alloy. A thermal fatigue test device characterized by being present.
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|---|---|---|---|
| JP2001222081A JP2003035644A (en) | 2001-07-23 | 2001-07-23 | Method and equipment for thermal fatigue test |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001222081A JP2003035644A (en) | 2001-07-23 | 2001-07-23 | Method and equipment for thermal fatigue test |
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| Publication Number | Publication Date |
|---|---|
| JP2003035644A true JP2003035644A (en) | 2003-02-07 |
Family
ID=19055633
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001222081A Pending JP2003035644A (en) | 2001-07-23 | 2001-07-23 | Method and equipment for thermal fatigue test |
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Cited By (14)
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| JP2005256858A (en) * | 2004-03-09 | 2005-09-22 | Railway Technical Res Inst | Brake disc for vehicle |
| JP2006162472A (en) * | 2004-12-08 | 2006-06-22 | Sumitomo Metal Ind Ltd | Method, device and test piece for testing thermal fatigue |
| KR101225686B1 (en) * | 2010-10-28 | 2013-01-23 | 삼성중공업 주식회사 | Jig for fatigue testing apparatus |
| CN104792638A (en) * | 2015-03-20 | 2015-07-22 | 北京航空航天大学 | Device and method for testing metal corrosion fatigue crack extension |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60159640A (en) * | 1984-01-31 | 1985-08-21 | Mitsubishi Heavy Ind Ltd | Heated test piece |
| JPS6148349U (en) * | 1984-09-05 | 1986-04-01 | ||
| JPS6262247U (en) * | 1985-10-08 | 1987-04-17 | ||
| JPS63132346U (en) * | 1987-02-20 | 1988-08-30 | ||
| JPH0720031A (en) * | 1993-06-30 | 1995-01-24 | Toyota Central Res & Dev Lab Inc | Method and device for thermal fatigue test |
| JPH0835403A (en) * | 1994-07-27 | 1996-02-06 | Fuji Electric Co Ltd | Life consumption monitoring material testing device to which material test piece is attached |
-
2001
- 2001-07-23 JP JP2001222081A patent/JP2003035644A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60159640A (en) * | 1984-01-31 | 1985-08-21 | Mitsubishi Heavy Ind Ltd | Heated test piece |
| JPS6148349U (en) * | 1984-09-05 | 1986-04-01 | ||
| JPS6262247U (en) * | 1985-10-08 | 1987-04-17 | ||
| JPS63132346U (en) * | 1987-02-20 | 1988-08-30 | ||
| JPH0720031A (en) * | 1993-06-30 | 1995-01-24 | Toyota Central Res & Dev Lab Inc | Method and device for thermal fatigue test |
| JPH0835403A (en) * | 1994-07-27 | 1996-02-06 | Fuji Electric Co Ltd | Life consumption monitoring material testing device to which material test piece is attached |
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|---|---|---|---|---|
| JP2005256858A (en) * | 2004-03-09 | 2005-09-22 | Railway Technical Res Inst | Brake disc for vehicle |
| JP2006162472A (en) * | 2004-12-08 | 2006-06-22 | Sumitomo Metal Ind Ltd | Method, device and test piece for testing thermal fatigue |
| JP4687088B2 (en) * | 2004-12-08 | 2011-05-25 | 住友金属工業株式会社 | Thermal fatigue test method, thermal fatigue test apparatus, and thermal fatigue test piece |
| KR101225686B1 (en) * | 2010-10-28 | 2013-01-23 | 삼성중공업 주식회사 | Jig for fatigue testing apparatus |
| WO2015173843A1 (en) * | 2014-05-13 | 2015-11-19 | 日鉄住金ハード株式会社 | Member for molten metal plating bath |
| CN104792638A (en) * | 2015-03-20 | 2015-07-22 | 北京航空航天大学 | Device and method for testing metal corrosion fatigue crack extension |
| CN105784527A (en) * | 2016-05-04 | 2016-07-20 | 武汉理工大学 | Heat-force coupled fatigue and wear accelerated testing apparatus and method |
| CN105784527B (en) * | 2016-05-04 | 2018-08-07 | 武汉理工大学 | A kind of Acceleration study device and method of thermal stress coupling fatigue/abrasion |
| CN110296883A (en) * | 2018-03-22 | 2019-10-01 | 株式会社岛津制作所 | Clip tooth and fixture |
| EP3543676A1 (en) * | 2018-03-22 | 2019-09-25 | Shimadzu Corporation | Gripping teeth and gripper |
| CN109855850A (en) * | 2018-12-22 | 2019-06-07 | 昆明理工大学 | A kind of Piston Thermal Fatigue Test platform of rotary lifting-type |
| CN112304788A (en) * | 2020-09-21 | 2021-02-02 | 中国石油天然气集团有限公司 | Thermal production well casing multi-turn thermal cycle test device and use method |
| KR102267228B1 (en) * | 2020-11-23 | 2021-06-21 | 주식회사 지노테크 | High temperature durability tester |
| CN112903487A (en) * | 2021-01-25 | 2021-06-04 | 西北工业大学 | Thermal fatigue test system for porous layer plate and strip temperature gradient |
| CN113866007A (en) * | 2021-08-19 | 2021-12-31 | 中国原子能科学研究院 | Device suitable for high and low temperature radioactive plate-shaped fatigue test |
| CN117433936A (en) * | 2023-12-19 | 2024-01-23 | 中航试金石检测科技(成都)有限公司 | Small sample low cycle fatigue testing device |
| CN117433936B (en) * | 2023-12-19 | 2024-04-05 | 中航试金石检测科技(成都)有限公司 | Small sample low cycle fatigue testing device |
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