WO2015107652A1 - Estimation method using calibration curve of remaining lifespan of tubing having bainite structure - Google Patents

Estimation method using calibration curve of remaining lifespan of tubing having bainite structure Download PDF

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Publication number
WO2015107652A1
WO2015107652A1 PCT/JP2014/050681 JP2014050681W WO2015107652A1 WO 2015107652 A1 WO2015107652 A1 WO 2015107652A1 JP 2014050681 W JP2014050681 W JP 2014050681W WO 2015107652 A1 WO2015107652 A1 WO 2015107652A1
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pipe
outer diameter
calibration curve
crack
remaining life
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PCT/JP2014/050681
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French (fr)
Japanese (ja)
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西田　秀高
栄郎 松村
啓司 森下
荒川　大輔
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中国電力株式会社
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Priority to JP2015512419A priority Critical patent/JPWO2015107652A1/en
Priority to PCT/JP2014/050681 priority patent/WO2015107652A1/en
Publication of WO2015107652A1 publication Critical patent/WO2015107652A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N25/00—Investigating or analyzing materials by the use of thermal means
    • G01N25/16—Investigating or analyzing materials by the use of thermal means by investigating thermal coefficient of expansion

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  • the present invention relates to a method for estimating the remaining life of a pipe having a bainite structure using a calibration curve.
  • Metal piping such as power steam piping used in thermal power generation facilities and nuclear power generation facilities is subject to high-temperature and high-pressure conditions for a long period of time, so plastic deformation gradually progresses and breaks when the creep life is reached. End up. Therefore, in order to safely and economically operate thermal power generation facilities and nuclear power generation facilities, it is required to accurately predict the remaining creep life.
  • a method for estimating the remaining life of a metal pipe As a method for estimating the remaining life of a metal pipe, a method is known in which a calibration curve representing the relationship between the progress of creep damage and the remaining life is prepared and the remaining life is estimated based on this. For example, in Patent Document 1, a bending moment acting on a bend portion is calculated by measuring deformation amounts at a plurality of positions before and after the bend portion (maximum damage site) of a steam pipe, and bending of the bend portion of the pipe obtained in advance is calculated. It is described that the creep damage of the bend portion is obtained from the relationship between the moment and the creep damage.
  • the mechanism of creep damage differs depending on the metal structure.
  • the damage mechanism is not well understood, and there is no established method for estimating the remaining life. For this reason, it is difficult to know the proper repair and replacement timing of piping.
  • the present invention has been made in view of such circumstances, and an object thereof is to provide a method for estimating the remaining life of a pipe having a bainite structure using a calibration curve.
  • the present invention is a method for estimating the remaining life of a cylindrical pipe having a bainite structure, which is creep-damaged by heating and pressurization, using a calibration curve.
  • a calibration curve showing the relationship between the pipes, and measuring the outer diameter of the pipe to obtain a bulge rate in the diameter direction of the pipe, and based on the bulge rate of the pipe and the calibration curve, The remaining life is estimated.
  • the outer diameter of the test specimen is a maximum value of the outer diameter measured a plurality of times from different directions, and the outer diameter of the pipe was measured a plurality of times from different directions. It is the maximum value of the outer diameter of the pipe.
  • the bulging rate of the test specimen is the outer diameter of the test specimen after applying the heat and internal pressure to the outer diameter of the test specimen before applying the heat and internal pressure. It is a ratio of diameters.
  • the bulging rate of the test specimen of the pipe is the ratio of the outer diameter after the addition to the outer diameter before applying heat and internal pressure, so that the parameter does not depend on the length of the initial outer diameter of the pipe. Is obtained. Therefore, the calibration curve created based on such parameters can be used to estimate the remaining life of pipes with different sizes (different outer diameters) from the test specimen. A calibration curve can be applied.
  • Another aspect of the present invention is that when measuring the outer diameter of the test body, it is also determined whether or not a crack has occurred in the test body, and when it is determined that a crack has occurred. Measures the length of the crack having the maximum length among the generated cracks, and shows another calibration curve indicating the relationship between the measured crack length of the specimen and the remaining life of the specimen.
  • the remaining life of a pipe having a bainite structure can be estimated using a calibration curve.
  • FIG. 2 is a diagram illustrating the configuration of a test body 10. It is a figure explaining the test conditions of an internal pressure creep test. It is a figure which shows the measurement result of an outer diameter, and the calculation result of a bulging rate. It is a graph of the calibration curve showing the relationship between the bulging rate and the life ratio. It is a figure explaining the measurement location of the outer diameter of piping of an actual machine. It is a flowchart which shows the procedure which produces a calibration curve by performing the internal pressure creep test to the test body.
  • FIG. 2 is a diagram illustrating the configuration of a test body 10. It is a figure explaining the test conditions of an internal pressure creep test. It is a figure which shows the measurement result of the outer diameter of the test body a. It is a figure which shows the measurement result of the maximum crack length of the test body a. It is a SEM photograph of the test body a in the 6th halfway stop. It is a figure which shows the measurement result of the outer diameter of the test body b. It is a figure which shows the measurement result of the maximum crack length of the test body b. It is a graph of the calibration curve showing the relationship between the bulging rate and the life ratio. It is a graph of the calibration curve showing the relationship between the maximum crack length and the life ratio.
  • First Embodiment> 1A and 1B are flowcharts illustrating a method for estimating the remaining life of a pipe according to the first embodiment.
  • a calibration curve is created by performing an internal pressure creep test on a test body that simulates piping (FIG. 1A), and then the remaining life of the piping is estimated based on the calibration curve (FIG. 1B).
  • the internal pressure creep test is a test for confirming creep damage by heating a test body to which an internal pressure is applied. The remaining life estimation method will be described below with reference to these flowcharts.
  • FIG. 2 is a diagram for explaining the configuration of this test body.
  • the test body 10 is made of a steel material and includes a hollow substantially cylindrical tube member 11, a first plug member 12, and a second plug member 13.
  • Both ends of the tube member 11 are sealed with a first plug member 12 and a second plug member 13, and an injection tube 14 is inserted into the first plug member 12 from the outside.
  • the injection tube 14 is a tube for injecting a high-temperature fluid 15 described later into the tube member 11. For this reason, the inside of the tube member 11 and the inside of the injection tube 14 are in communication with each other.
  • the material of the pipe member 11 is a material that has a bainite structure and that undergoes creep damage due to heating and pressurization, and is made of the same material as the piping whose remaining life is to be estimated.
  • chromium molybdenum steel is used.
  • the shape of the pipe member 11 is a cylindrical shape because it simulates piping. However, from the viewpoint of facilitating handling, a metal pipe having a smaller diameter than the pipe is used. As shown in FIG. 3, the diameter phi 10 of the test body 10 (tube member 11) is 56.5 mm.
  • the test body 10 has a heating furnace (not shown) in a state where the longitudinal direction of the tube member 11 is substantially horizontal so that the high-temperature fluid 15 injected into the tube member 11 is uniformly accumulated in the tube member 11. ) In the interior space.
  • a high-temperature fluid 15 such as water vapor is injected into the injection tube 14
  • the high-temperature fluid 15 flows into the hollow portion in the tube member 11, and the test body 10 receives a stress in the diametrical direction, and its internal pressure increases.
  • the temperature of the test body 10 also rises. Thus, creep damage is caused to the pipe member 11 by heating and pressurizing the pipe member 11.
  • the heating temperature of the test body 10 is not particularly limited as long as the tube member 11 has a bainite structure, but is, for example, in the range of 210 ° C. to 550 ° C., and more preferably in the range of 350 ° C. to 550 ° C. Moreover, it is preferable that it is close to the temperature of the fluid (steam etc.) which distribute
  • the range of the pressure applied to the test body 10 is not particularly limited as long as it is higher than the normal pressure (0.1 MPa), but is, for example, 0.2 MPa to 1000 MPa. Further, it is more preferably 0.3 MPa to 500 MPa, and further preferably 0.5 MPa to 300 MPa.
  • the tube member 11 is continuously heated and pressurized, and a predetermined time interval (500 hours to 2000 hours, about 1000 hours on average) is kept until the test body 10 breaks.
  • the outer diameter that is, the outer diameter of the tube member 11 is measured.
  • the portion (the tube member 11, the first plug member 12, and the second plug member 13) excluding the injection tube 14 in the test body 10 has an axial length of 385 mm.
  • the measurement position of the outer diameter of the test body 10 is a cross section 16 (P) at a position spaced 195 mm in the axial direction from one end on the first plug member 12 side and 190 mm in the axial direction from one end on the second plug member 13 side. -Q cross section).
  • the pipe member 11 was a pipe made of chromium molybdenum steel (STPA 22, JIS standard G 3457 “arc welded carbon steel pipe for piping”).
  • the measurement of the outer diameter of the test body 10 is performed by measuring the length of the outer diameter in the first direction (outer diameter ⁇ 1 ) in the cross section 16 and the outer diameter in the second direction perpendicular to the first direction (outer diameter).
  • the length of the diameter ⁇ 2 ) was measured, and the maximum value of these was taken as the measured value of the outer diameter.
  • the number of times of measurement of the outer diameter at each measurement timing may be any number, and the measurement direction of the outer diameter may be an arbitrary direction instead of a perpendicular direction.
  • the heating temperature of the test body 10 was 550 degreeC, and the internal pressure of the test body 10 was 145 MPa.
  • outer diameter (phi) 10 maximum value of outer diameter (phi) 1 and outer diameter (phi) 2 ) of the test body 10 before a test was 56.5 mm.
  • the test result of this internal pressure creep test is shown in FIG.
  • the outer diameter of the test body 10 is measured after 1500 hours (second suspension), after 2100 hours (third suspension), and 4000 hours after the start of applying heat and internal pressure ( 4th stop), after 5563 hours (5th stop), 6400 hours (6th stop), 7195 hours (7th stop), and 8437 hours (breakage of specimen 10) Time).
  • the life ratio at the second halfway stop (heating and pressing time / breaking time) is 0.18, the life ratio at the third halfway stop is 0.25, and the fourth halfway stop.
  • the life ratio at 0.45, the life ratio at the 5th stop is 0.66, the life ratio at the 6th stop is 0.76, and the life ratio at the 7th stop is 0.85
  • the life ratio at break is 1.00.
  • the swelling rate of the test body 10 obtained from the measured value of the outer diameter is 0.18% at the second halfway stop, 0.18% at the third halfway stop, 0.35% at the fourth halfway stop, It is 0.71% at the fifth break, 0.88% at the sixth break, 1.06% at the seventh break, and 2.48% at break.
  • these swelling rates were calculated
  • FIG. 5 is a calibration curve graph created based on the above measurement results and showing the relationship between the life ratio and the bulging rate.
  • the outer diameter of the actual pipe is measured (S7).
  • the length of the outer diameter in the first direction (outer diameter ⁇ 30A ) and the length of the outer diameter in the second direction (outer diameter ⁇ 30B ) orthogonal to the first direction are measured, and the larger one is the pipe 30. Obtained as the outer diameter value of.
  • the outer diameter value is acquired before operation (before heating and pressurization) and during operation (during regular inspection, etc.).
  • the number of times of measurement of the outer diameter is not limited to two as in this example, and may be any number, and the measurement direction of the outer diameter is not a perpendicular direction but may be an arbitrary direction.
  • the remaining life of the pipe is estimated based on the measured value of the outer diameter and the calibration curve created in S6 (S8 in FIG. 1B). That is, the bulging rate is calculated based on the initial outer diameter value of the pipe 30 before operation and the outer diameter value of the pipe 30 during operation. Then, the calculated bulging rate is applied to a calibration curve created with the test body 10.
  • the swelling rate was B 1 represents, calibration curve 21 the life ratio of the time of the bulging ratio is B, ie L 1 becomes life ratio.
  • the outer diameter of the test body 10 swelled in the diametric direction is obtained by performing an internal pressure creep test in which the pipe test body 10 is heated and an internal pressure is applied.
  • this bulge amount is the length of the initial outer diameter of the pipe.
  • This parameter does not depend on. Therefore, the calibration curve created based on such parameters can also be used to estimate the remaining life of piping having a different size (different outer diameter) from that of the specimen. For example, this calibration curve can be applied to an actual machine larger than the test body 10.
  • Second Embodiment The present inventors have found that when a pipe having a bainite structure is cracked, the length of the crack having the maximum length among the cracks is correlated with the remaining life. Therefore, the present inventors create a calibration curve related to the relationship between the maximum length of cracks and the remaining life in addition to the calibration curve related to the relationship between the bulging amount and the remaining life as described in the first embodiment, A method for estimating the remaining life of piping using these two calibration curves was conceived.
  • FIG. 7A and 7B are flowcharts showing the remaining life estimation method according to the present embodiment.
  • FIG. 7A is a flowchart which shows the procedure which produces a calibration curve.
  • FIG. 7B is a flowchart showing a procedure for estimating the remaining life of the pipe based on the calibration curve.
  • the second embodiment in addition to the measurement of the outer diameter described in the first embodiment, it is determined whether or not a crack has occurred on the surface of the test body 10. And when the crack has generate
  • test body 10 has cracks is determined by, for example, observing the structure with a scanning electron microscope (SEM). This tissue observation is performed on a predetermined range in the test body 10, for example, a predetermined range at a position where the outer diameter is measured (for example, the central portion in the axial direction). Further, the width of the predetermined range is arbitrary, but is, for example, 0.3 mm 2 to 1.0 mm 2 .
  • test body a and test body b having different outer diameters.
  • the test using the test specimen a is a test using the same test specimen 10 as in the first embodiment.
  • the test by the test body b is a test by the test body 10 having an initial outer diameter ⁇ 10 of 56.6 mm.
  • the test conditions are a heating temperature of 550 ° C. and an internal pressure of 145 MPa.
  • FIG.10 and FIG.11 is the figure which put together the test result of the test body a.
  • FIG. 10 shows the measurement result of the outer diameter, which is the same as FIG.
  • FIG. 11 is a diagram showing the results of the maximum crack length of the test body a.
  • the occurrence of cracks in the test specimen a was confirmed at the sixth stop (6400 hours later), after 7195 hours (seventh stop), and when the test specimen a was broken ( 8437 hours later), and the maximum crack lengths measured at that time were 518 ⁇ m, 1.09 mm, and 18.1 mm, respectively.
  • the bulging rate of the specimen a is the same as in the first embodiment (0.18% for the second halfway stop, 0.18% for the third halfway stop, and 0.35 for the fourth halfway stop. %, 0.71% at the 5th stop, 0.88% at the 6th stop, 1.06% at the 7th stop, 2.48% at break).
  • FIG. 12 shows an SEM image of the specimen a at the time of the sixth suspension.
  • the test body a has cracks 41 and 42, but the gap between the cracks 41 and 42 is broken.
  • the length of the cut portion is predetermined with respect to the longer length of both cracks adjacent to the cut portion. If the ratio is less than or equal to the above, the crack length was determined by regarding that both cracks and the cut-off portion were one connected crack.
  • the predetermined ratio is preferably, for example, half, more preferably 40%, and still more preferably 30%.
  • the crack 41 and the crack 42 include the cut portion.
  • the crack length was 518 ⁇ m.
  • the length of the crack is the length of a straight line connecting both ends of the crack, and the length of the part that is cut off is formed by the part that is cut off and the two cracks adjacent to the cut part.
  • the method of measuring the length of a crack is not specifically limited, A well-known method can be used, For example, it measures by performing surface structure
  • FIG. 13 shows the measurement result of the outer diameter of the specimen b.
  • the measurement of the outer diameter of the test specimen b is 1500 hours after the start of application of heat and internal pressure (second suspension), 2100 hours (third suspension), and 4000 hours later ( 4th stoppage), after 5562 hours (5th stoppage), after 6400 hours (6th stoppage), and after 6507 hours (when the specimen b was broken).
  • the bulging rate calculated from these outer diameters is 0.00% for the second halfway stop, 0.00% for the third halfway stop, 0.00% for the fourth halfway stop, and the fifth halfway. It was 0.53% at the stop, 0.71% at the sixth stop, and 0.71% at break.
  • the life ratio at the second halfway stop is 0.23
  • the life ratio at the third halfway stop is 0.32
  • the fourth The life ratio at the middle stop is 0.61
  • the life ratio at the fifth halfway stop is 0.85
  • the life ratio at the sixth halfway stop is 0.98
  • the life ratio at break is 1.00. is there.
  • FIG. 14 shows the measurement result of the maximum crack length of the specimen b.
  • the maximum crack length after 5562 hours from the start of the test (fifth stop) is 764 ⁇ m
  • the maximum crack length after 6400 hours from the start of the test is 3.41 mm.
  • the maximum crack length at the time of rupture was 23.7 mm.
  • the measurement interval of the outer diameter and the maximum crack length of the specimen b is about 500 hours to about 2000 hours as in the first embodiment, and averages about 1000 hours. is there.
  • FIG. 15 is a calibration curve 51 created based on the above test results and showing the relationship between the bulging rate and the life ratio. As shown in the figure, the calibration curve 51 is exponentially approximated so as to pass through the origin.
  • FIG. 16 is a calibration curve 61 showing the relationship between the maximum crack length and the life ratio calibration curve. As shown in the figure, exponential approximation was performed so that the calibration curve 61 also passes through the origin.
  • the maximum crack length of the actual pipe is measured (S22). Specifically, for example, the maximum crack length in the range where the structure is observed in S21 is measured.
  • the measured maximum crack length is fitted to a calibration curve 61 indicating the relationship between the maximum crack length and the life ratio calibration curve (S23), and the remaining life of the pipe is estimated (S24).
  • the maximum crack length in actual use is a C 3
  • the life ratio of the calibration curve 61 at the maximum crack length is C3, i.e. L 3 becomes life ratio.
  • the outer diameter of the actual machine pipe is measured (S25). For example, the outer diameter of the central part of a pipe that is susceptible to creep damage is measured.
  • the measured outer diameter is applied to a calibration curve 51 representing the relationship between the bulging rate and the life ratio (S26), and the remaining life of the pipe is estimated (S27).
  • the bulging rate is obtained from the measured outer diameter value, and a bulging rate-life ratio calibration curve is created from the obtained bulging rate to obtain the life ratio of the pipe.
  • the actual bulging ratio is B 2
  • bulging rate life ratio of the calibration curve 51 when the B 2 i.e. L 2 is life ratio.
  • a calibration curve representing the relationship between the maximum crack length and the remaining life is prepared, and if a crack has occurred in the pipe, the maximum crack length is By estimating the remaining life of the pipe based on the calibration curve representing the relationship between the life and the remaining life and the actual measured value of the maximum crack length, it is possible to accurately estimate the remaining life of the pipe having the bainite structure.

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Abstract

The objective of the present invention is to estimate the remaining lifespan of tubing having a bainite structure. The present invention is an estimation method that uses a calibration curve of the remaining lifespan of cylindrical tubing having a bainite structure and that incurs creep failure as a result of heating and pressurization. A hollow sample (10) of the same material as the tubing is subjected to heat and pressure, the outer diameter is measured, and the outer diameter is measured a plurality of instances at predetermined times in order to create a calibration curve indicating the relationship between the expansion rate in the diametral direction of the sample (10) and the remaining lifespan of the sample (10). Afterwards, the outer diameter of the tubing is measured, and the remaining lifespan of the tubing is estimated on the basis of the aforementioned calibration curve and the expansion rate in the diametral direction of the tubing.

Description

ベイナイト組織を有する配管の余寿命を検量線を用いて推定する方法A method for estimating the remaining life of piping with a bainite structure using a calibration curve
　本発明は、ベイナイト組織を有する配管の余寿命を検量線を用いて推定する方法に関する。 The present invention relates to a method for estimating the remaining life of a pipe having a bainite structure using a calibration curve.
　火力発電設備や原子力発電設備等において用いられる動力用蒸気配管などの金属配管は、長期間に渡って高温・高圧条件におかれることから、徐々に塑性変形が進み、クリープ寿命に達すると破断してしまう。従って、火力発電設備や原子力発電設備を安全かつ経済的に運転するためには、クリープ余寿命を的確に予測することが求められる。 Metal piping such as power steam piping used in thermal power generation facilities and nuclear power generation facilities is subject to high-temperature and high-pressure conditions for a long period of time, so plastic deformation gradually progresses and breaks when the creep life is reached. End up. Therefore, in order to safely and economically operate thermal power generation facilities and nuclear power generation facilities, it is required to accurately predict the remaining creep life.
　金属配管の余寿命を推定する方法としては、クリープ損傷の進行と余寿命との関係を表す検量線を作成しておき、これに基づいて余寿命を推定する手法が知られている。例えば特許文献１には、蒸気配管のベンド部（最大損傷部位）前後の複数の位置において変形量を測定することによりベンド部に働く曲げモーメントを計算し、予め求めてある配管のベンド部の曲げモーメントとクリープ損傷との関係から、ベンド部のクリープ損傷を求めることが記載されている。 As a method for estimating the remaining life of a metal pipe, a method is known in which a calibration curve representing the relationship between the progress of creep damage and the remaining life is prepared and the remaining life is estimated based on this. For example, in Patent Document 1, a bending moment acting on a bend portion is calculated by measuring deformation amounts at a plurality of positions before and after the bend portion (maximum damage site) of a steam pipe, and bending of the bend portion of the pipe obtained in advance is calculated. It is described that the creep damage of the bend portion is obtained from the relationship between the moment and the creep damage.
特開２００３－２３２７１９号公報JP 2003-232719 A
　ただ、クリープ損傷のメカニズムは金属組織によって異なっている。特に、炭素鋼を所定条件下で冷却した場合にのみ得られるベイナイト組織を有する鉄鋼配管については、その損傷メカニズムがよく分かっておらず、確立された余寿命の推定方法がない。そのため、適切な配管の補修、交換タイミングを知ることが難しくなっている。 However, the mechanism of creep damage differs depending on the metal structure. In particular, for steel pipes having a bainite structure obtained only when carbon steel is cooled under predetermined conditions, the damage mechanism is not well understood, and there is no established method for estimating the remaining life. For this reason, it is difficult to know the proper repair and replacement timing of piping.
　本発明はこのような事情に鑑みてなされたものであり、その目的は、ベイナイト組織を有する配管の余寿命を検量線を用いて推定する方法を提供することにある。 The present invention has been made in view of such circumstances, and an object thereof is to provide a method for estimating the remaining life of a pipe having a bainite structure using a calibration curve.
　本発明者らは、ベイナイト組織を有する配管のクリープ損傷のメカニズムについて研究を重ねた結果、ベイナイト組織を有する配管は加熱及び加圧によって直径方向に膨出し、この膨出率が余寿命判断の適切な指標になり得ること、また、ベイナイト組織を有する配管に亀裂が発生している場合はその亀裂の最大の長さが余寿命と相関関係にあることを見出し、本発明を完成するに至った。 As a result of repeated research on the creep damage mechanism of pipes having a bainite structure, the present inventors have found that pipes having a bainite structure bulge in the diameter direction by heating and pressurization, and this bulging rate is appropriate for determining the remaining life. It has been found that the maximum length of the crack has a correlation with the remaining life when the pipe having a bainite structure has a crack, and the present invention has been completed. .
　すなわち、本発明は、加熱及び加圧によりクリープ損傷を受ける、ベイナイト組織を有する円筒形状の配管の余寿命を検量線を用いて推定する方法であって、材質が前記配管と同一の、中空の試験体に熱及び内圧を加えて外径を測定し、所定時間をおいて前記外径の測定を複数回行うことにより、前記試験体の直径方向の膨出率と前記試験体の余寿命との関係を示す検量線を作成し、前記配管の外径を測定することで、前記配管の直径方向の膨出率を求め、前記配管の膨出率と前記検量線とに基づき、前記配管の余寿命を推定することを特徴とする。 That is, the present invention is a method for estimating the remaining life of a cylindrical pipe having a bainite structure, which is creep-damaged by heating and pressurization, using a calibration curve. By applying heat and internal pressure to the test body and measuring the outer diameter, and measuring the outer diameter a plurality of times over a predetermined time, the bulge rate in the diameter direction of the test body and the remaining life of the test body A calibration curve showing the relationship between the pipes, and measuring the outer diameter of the pipe to obtain a bulge rate in the diameter direction of the pipe, and based on the bulge rate of the pipe and the calibration curve, The remaining life is estimated.
　また、本発明の他の一つは、前記試験体の外径は、異なる方向から複数回測定された外径の最大値であり、前記配管の外径は、異なる方向から複数回測定された前記配管の外径の最大値であることを特徴とする。 Another aspect of the present invention is that the outer diameter of the test specimen is a maximum value of the outer diameter measured a plurality of times from different directions, and the outer diameter of the pipe was measured a plurality of times from different directions. It is the maximum value of the outer diameter of the pipe.
　ベイナイト組織を有する配管では、外径が大きいほどクリープ損傷が進行していると考えられる。そこで、異なる方向から複数回測定した測定値のうち最大値を外径の値とすることで、クリープ損傷による寿命時期を正確に予測することができる。 In pipes having a bainite structure, it is considered that creep damage progresses as the outer diameter increases. Therefore, the life time due to creep damage can be accurately predicted by setting the maximum value among the measured values measured multiple times from different directions as the value of the outer diameter.
　また、本発明の他の一つは、前記試験体の膨出率は、前記熱及び内圧を加える前の前記試験体の外径に対する、前記熱及び内圧を加えた後の前記試験体の外径の比であることを特徴とする。 Another aspect of the present invention is that the bulging rate of the test specimen is the outer diameter of the test specimen after applying the heat and internal pressure to the outer diameter of the test specimen before applying the heat and internal pressure. It is a ratio of diameters.
　このように、配管の試験体の膨出率を、熱及び内圧を加える前の外径に対する、加えた後の外径の比とすることにより、配管の初期外径の長さに依存しないパラメータが得られる。したがって、このようなパラメータに基づき作成した検量線は、試験体とサイズの異なる（外径の異なる）配管の余寿命推定にも用いることができ、例えば試験体より大型の実機に対してもこの検量線を適用することができる。 In this way, the bulging rate of the test specimen of the pipe is the ratio of the outer diameter after the addition to the outer diameter before applying heat and internal pressure, so that the parameter does not depend on the length of the initial outer diameter of the pipe. Is obtained. Therefore, the calibration curve created based on such parameters can be used to estimate the remaining life of pipes with different sizes (different outer diameters) from the test specimen. A calibration curve can be applied.
　また、本発明の他の一つは、前記試験体の外径を測定する際には、前記試験体に亀裂が発生しているか否かも判定し、亀裂が発生していると判定した場合には、前記発生している亀裂のうち最大の長さを有する亀裂の長さを測定し、測定した前記試験体の亀裂の長さと前記試験体の余寿命との関係を示す他の検量線を作成し、前記配管の外径を測定する際には、前記配管に亀裂が発生しているか否かも判定し、亀裂が発生している判定した場合には、前記配管に存在する亀裂のうち最大の長さを有する亀裂の長さを測定し、測定した前記配管の亀裂の長さと前記他の検量線とに基づき、前記配管の余寿命を推定することを特徴とする。 Another aspect of the present invention is that when measuring the outer diameter of the test body, it is also determined whether or not a crack has occurred in the test body, and when it is determined that a crack has occurred. Measures the length of the crack having the maximum length among the generated cracks, and shows another calibration curve indicating the relationship between the measured crack length of the specimen and the remaining life of the specimen. When creating and measuring the outer diameter of the pipe, it is also determined whether or not a crack has occurred in the pipe. If it is determined that a crack has occurred, the largest of the cracks existing in the pipe is determined. The remaining life of the pipe is estimated based on the measured crack length of the pipe and the other calibration curve.
　このように、試験体について最大の亀裂の長さと余寿命との関係を表す検量線を作成しておき、配管に亀裂が発生している場合は、上記の検量線と、配管の最大亀裂長さの測定値とに基づき配管の余寿命を推定することで、ベイナイト組織を有する配管の余寿命を正確に推定することができる。 In this way, a calibration curve representing the relationship between the maximum crack length and the remaining life is prepared for the specimen, and if a crack has occurred in the pipe, the above calibration curve and the maximum crack length of the pipe By estimating the remaining life of the pipe based on the measured value, it is possible to accurately estimate the remaining life of the pipe having a bainite structure.
　本発明によれば、ベイナイト組織を有する配管の余寿命を検量線を用いて推定することができる。 According to the present invention, the remaining life of a pipe having a bainite structure can be estimated using a calibration curve.
試験体１０に内圧クリープ試験を行うことにより検量線を作成する手順を示すフローチャートである。It is a flowchart which shows the procedure which produces a calibration curve by performing the internal pressure creep test to the test body. 検量線に基づき配管の余寿命を推定する手順を示すフローチャートである。It is a flowchart which shows the procedure which estimates the remaining life of piping based on a calibration curve. 試験体１０の構成を説明する図である。FIG. 2 is a diagram illustrating the configuration of a test body 10. 内圧クリープ試験の試験条件を説明する図である。It is a figure explaining the test conditions of an internal pressure creep test. 外径の測定結果及び膨出率の算出結果を示す図である。It is a figure which shows the measurement result of an outer diameter, and the calculation result of a bulging rate. 膨出率と寿命比の関係を表す検量線のグラフである。It is a graph of the calibration curve showing the relationship between the bulging rate and the life ratio. 実機の配管の外径の測定箇所を説明する図である。It is a figure explaining the measurement location of the outer diameter of piping of an actual machine. 試験体１０に内圧クリープ試験を行うことにより検量線を作成する手順を示すフローチャートである。It is a flowchart which shows the procedure which produces a calibration curve by performing the internal pressure creep test to the test body. 検量線に基づき配管の余寿命を推定する手順を示すフローチャートである。It is a flowchart which shows the procedure which estimates the remaining life of piping based on a calibration curve. 試験体１０の構成を説明する図である。FIG. 2 is a diagram illustrating the configuration of a test body 10. 内圧クリープ試験の試験条件を説明する図である。It is a figure explaining the test conditions of an internal pressure creep test. 試験体ａの外径の測定結果を示す図である。It is a figure which shows the measurement result of the outer diameter of the test body a. 試験体ａの最大亀裂長さの測定結果を示す図である。It is a figure which shows the measurement result of the maximum crack length of the test body a. 第６回中途止めにおける試験体ａのＳＥＭ写真である。It is a SEM photograph of the test body a in the 6th halfway stop. 試験体ｂの外径の測定結果を示す図である。It is a figure which shows the measurement result of the outer diameter of the test body b. 試験体ｂの最大亀裂長さの測定結果を示す図である。It is a figure which shows the measurement result of the maximum crack length of the test body b. 膨出率と寿命比の関係を表す検量線のグラフである。It is a graph of the calibration curve showing the relationship between the bulging rate and the life ratio. 最大亀裂長さと寿命比の関係を表す検量線のグラフである。It is a graph of the calibration curve showing the relationship between the maximum crack length and the life ratio.
＜第１実施形態＞
　図１Ａ及び図１Ｂは、第１実施形態に係る配管の余寿命の推定方法を示すフローチャートである。本実施形態では、配管を模擬した試験体に対し、内圧クリープ試験を行うことにより検量線を作成し（図１Ａ）、次にこの検量線に基づき配管の余寿命を推定する（図１Ｂ）。なお、内圧クリープ試験とは、内圧を印加した試験体を加熱し、クリープ損傷を確認する試験である。以下、これらのフローチャートに従って、余寿命の推定方法を説明する。 <First Embodiment>
1A and 1B are flowcharts illustrating a method for estimating the remaining life of a pipe according to the first embodiment. In this embodiment, a calibration curve is created by performing an internal pressure creep test on a test body that simulates piping (FIG. 1A), and then the remaining life of the piping is estimated based on the calibration curve (FIG. 1B). The internal pressure creep test is a test for confirming creep damage by heating a test body to which an internal pressure is applied. The remaining life estimation method will be described below with reference to these flowcharts.
　この推定方法では、まず配管の試験体を加熱し、内圧を印加する（Ｓ１）。図２は、この試験体の構成を説明する図である。同図に示すように、試験体１０は、鋼材で作製され、中空の略円筒形状の管部材１１、第１栓部材１２、及び第２栓部材１３を含んで構成される。 In this estimation method, first, a pipe specimen is heated and an internal pressure is applied (S1). FIG. 2 is a diagram for explaining the configuration of this test body. As shown in the figure, the test body 10 is made of a steel material and includes a hollow substantially cylindrical tube member 11, a first plug member 12, and a second plug member 13.
　管部材１１の両端は、第１栓部材１２及び第２栓部材１３によって封止されており、このうち第１栓部材１２には外部から注入管１４が挿入されている。注入管１４は、後述する高温流体１５を管部材１１の内部に注入するための管である。このため、管部材１１の内部と注入管１４の内部とは互いに連通されている。 Both ends of the tube member 11 are sealed with a first plug member 12 and a second plug member 13, and an injection tube 14 is inserted into the first plug member 12 from the outside. The injection tube 14 is a tube for injecting a high-temperature fluid 15 described later into the tube member 11. For this reason, the inside of the tube member 11 and the inside of the injection tube 14 are in communication with each other.
　管部材１１の素材は、ベイナイト組織を有し、かつ、加熱及び加圧によってクリープ損傷を受ける素材であって、余寿命の推定対象となる配管と同一の素材で作製される。本実施形態では、クロムモリブデン鋼が用いられている。管部材１１の形状は、配管を模擬していることから円筒形状である。但し、取扱いを容易にする観点から、配管よりも小径の金属管が用いられている。図３に示すように、試験体１０（管部材１１）の直径φ１０は５６．５ｍｍである。 The material of the pipe member 11 is a material that has a bainite structure and that undergoes creep damage due to heating and pressurization, and is made of the same material as the piping whose remaining life is to be estimated. In this embodiment, chromium molybdenum steel is used. The shape of the pipe member 11 is a cylindrical shape because it simulates piping. However, from the viewpoint of facilitating handling, a metal pipe having a smaller diameter than the pipe is used. As shown in FIG. 3, the diameter phi 10 of the test body 10 (tube member 11) is 56.5 mm.
　この試験体１０は、管部材１１に注入された高温流体１５が管部材１１内に万遍なく蓄積されるように、管部材１１の長手方向が略水平となる状態で加熱炉（図示せず）の内部空間に設置される。そして、注入管１４に水蒸気等の高温流体１５を注入すると、高温流体１５は管部材１１内の空洞部に流入し、試験体１０は直径方向の応力を受け、その内圧が上昇する。また、試験体１０の温度も上昇する。このように、管部材１１を加熱、加圧することにより、管部材１１にクリープ損傷を生じさせる。 The test body 10 has a heating furnace (not shown) in a state where the longitudinal direction of the tube member 11 is substantially horizontal so that the high-temperature fluid 15 injected into the tube member 11 is uniformly accumulated in the tube member 11. ) In the interior space. When a high-temperature fluid 15 such as water vapor is injected into the injection tube 14, the high-temperature fluid 15 flows into the hollow portion in the tube member 11, and the test body 10 receives a stress in the diametrical direction, and its internal pressure increases. Moreover, the temperature of the test body 10 also rises. Thus, creep damage is caused to the pipe member 11 by heating and pressurizing the pipe member 11.
　試験体１０の加熱温度は、管部材１１がベイナイト組織を有する限り特に限定されないが、例えば２１０℃～５５０℃の範囲であり、３５０℃～５５０℃の範囲であることがより好ましい。また、余寿命の推定対象となる実機配管に流通する流体（水蒸気等）の温度に近いことが好ましい。試験体１０に加える圧力の範囲は、常圧（０．１ＭＰａ）よりも高ければ特に限定されないが、例えば０．２ＭＰａ～１０００ＭＰａである。また、０．３ＭＰａ～５００ＭＰａであることがより好ましく、０．５ＭＰａ～３００ＭＰａであることがさらに好ましい。 The heating temperature of the test body 10 is not particularly limited as long as the tube member 11 has a bainite structure, but is, for example, in the range of 210 ° C. to 550 ° C., and more preferably in the range of 350 ° C. to 550 ° C. Moreover, it is preferable that it is close to the temperature of the fluid (steam etc.) which distribute | circulates to the actual machine piping used as the estimation object of remaining life. The range of the pressure applied to the test body 10 is not particularly limited as long as it is higher than the normal pressure (0.1 MPa), but is, for example, 0.2 MPa to 1000 MPa. Further, it is more preferably 0.3 MPa to 500 MPa, and further preferably 0.5 MPa to 300 MPa.
　このように、管部材１１を連続的に加熱及び加圧した状態とし、試験体１０が破断するまで所定の時間間隔（５００時間～２０００時間，平均すると約１０００時間）をおきながら試験体１０の外径、すなわち管部材１１の外径を測定していく。 In this way, the tube member 11 is continuously heated and pressurized, and a predetermined time interval (500 hours to 2000 hours, about 1000 hours on average) is kept until the test body 10 breaks. The outer diameter, that is, the outer diameter of the tube member 11 is measured.
　具体的には、図１Ａのフローチャートに示すように、試験体１０が破断していない場合は（Ｓ２：ＮＯ）、所定の測定タイミングが到来した時点で（Ｓ３：ＹＥＳ）、試験体１０の外径を測定する（Ｓ４）。試験体１０が破断した場合は（Ｓ２：ＹＥＳ）、その時点における試験体１０の外径を測定し（Ｓ５）、後述する膨出率と寿命比の関係を表す検量線の作成に移行する（Ｓ６）。 Specifically, as shown in the flowchart of FIG. 1A, when the specimen 10 is not broken (S2: NO), when the predetermined measurement timing arrives (S3: YES), the outside of the specimen 10 The diameter is measured (S4). When the test body 10 is ruptured (S2: YES), the outer diameter of the test body 10 at that time is measured (S5), and the process proceeds to the creation of a calibration curve representing the relationship between the bulging rate and the life ratio described later ( S6).
　ここで、発明者らが行った内圧クリープ試験について具体的に説明する。 Here, the internal pressure creep test conducted by the inventors will be specifically described.
　まず、使用した試験体１０の寸法等について説明する。図２に示すように、試験体１０における注入管１４を除いた部分（管部材１１、第１栓部材１２、第２栓部材１３）は、軸方向の長さが３８５ｍｍである。また、試験体１０の外径の測定位置は、第１栓部材１２の側の一端から軸方向に１９５ｍｍ、第２栓部材１３の側の一端から軸方向に１９０ｍｍ離間した位置における断面１６（Ｐ－Ｑ断面）とした。このように管部材１１の軸方向中央部を外径の測定位置としたのは、かかる位置が最も応力を受け易く、クリープ損傷が起きやすいと考えられるからである。 First, the dimensions of the used specimen 10 will be described. As shown in FIG. 2, the portion (the tube member 11, the first plug member 12, and the second plug member 13) excluding the injection tube 14 in the test body 10 has an axial length of 385 mm. Further, the measurement position of the outer diameter of the test body 10 is a cross section 16 (P) at a position spaced 195 mm in the axial direction from one end on the first plug member 12 side and 190 mm in the axial direction from one end on the second plug member 13 side. -Q cross section). The reason why the axially central portion of the pipe member 11 is set as the measurement position of the outer diameter in this way is that such a position is most susceptible to stress and creep damage is likely to occur.
　管部材１１には、クロムモリブデン鉄鋼鋼材で作られた配管（ＳＴＰＡ２２、ＪＩＳ規格　Ｇ　３４５７「配管用アーク溶接炭素鋼鋼管」）を用いた。 The pipe member 11 was a pipe made of chromium molybdenum steel (STPA 22, JIS standard G 3457 “arc welded carbon steel pipe for piping”).
　試験体１０の外径の測定は、図２に示すように、断面１６における第１方向の外径（外径φ１）の長さと、第１方向と直交する第２方向の外径（外径φ２）の長さを測定し、これらのうちの最大値を外径の測定値とした。なお、各測定タイミングにおける外径の測定回数は何回でもよく、また外径の測定方向も直交する方向でなく任意の方向でよい。 As shown in FIG. 2, the measurement of the outer diameter of the test body 10 is performed by measuring the length of the outer diameter in the first direction (outer diameter φ 1 ) in the cross section 16 and the outer diameter in the second direction perpendicular to the first direction (outer diameter). The length of the diameter φ 2 ) was measured, and the maximum value of these was taken as the measured value of the outer diameter. In addition, the number of times of measurement of the outer diameter at each measurement timing may be any number, and the measurement direction of the outer diameter may be an arbitrary direction instead of a perpendicular direction.
　また、図３に示すように、試験体１０の加熱温度は５５０℃、試験体１０の内圧は１４５ＭＰａとした。なお、試験前の試験体１０の外径φ１０（外径φ１と外径φ２の最大値）は５６．５ｍｍであった。 Moreover, as shown in FIG. 3, the heating temperature of the test body 10 was 550 degreeC, and the internal pressure of the test body 10 was 145 MPa. In addition, outer diameter (phi) 10 (maximum value of outer diameter (phi) 1 and outer diameter (phi) 2 ) of the test body 10 before a test was 56.5 mm.
　次に、この内圧クリープ試験の試験結果を図４に示す。同図に示すように、試験体１０の外径の測定は、熱及び内圧を加え始めてから１５００時間後（第２回中途止め）、２１００時間後（第３回中途止め）、４０００時間後（第４回中途止め）、５５６３時間後（第５回中途止め）、６４００時間後（第６回中途止め）、７１９５時間後（第７回中途止め）、及び８４３７時間後（試験体１０の破断時）に行った。 Next, the test result of this internal pressure creep test is shown in FIG. As shown in the figure, the outer diameter of the test body 10 is measured after 1500 hours (second suspension), after 2100 hours (third suspension), and 4000 hours after the start of applying heat and internal pressure ( 4th stop), after 5563 hours (5th stop), 6400 hours (6th stop), 7195 hours (7th stop), and 8437 hours (breakage of specimen 10) Time).
　なお、上記の試験時間から、第２回中途止めでの寿命比（加熱加圧時間／破断時間）は０．１８、第３回中途止めでの寿命比は０．２５、第４回中途止めでの寿命比は０．４７、第５回中途止めでの寿命比は０．６６、第６回中途止めでの寿命比は０．７６、第７回中途止めでの寿命比は０．８５、破断時の寿命比は１．００と求まる。 From the above test time, the life ratio at the second halfway stop (heating and pressing time / breaking time) is 0.18, the life ratio at the third halfway stop is 0.25, and the fourth halfway stop. The life ratio at 0.45, the life ratio at the 5th stop is 0.66, the life ratio at the 6th stop is 0.76, and the life ratio at the 7th stop is 0.85 The life ratio at break is 1.00.
　外径の測定値から求められる試験体１０の膨出率は、第２回中途止めでは０．１８％、第３回中途止めでは０．１８％、第４回中途止めでは０．３５％、第５回中途止めでは０．７１％、第６回中途止めでは０．８８％、第７回中途止めでは１．０６％、破断時では２．４８％である。なお、これらの膨出率は、次式（１）に従って求めた。 The swelling rate of the test body 10 obtained from the measured value of the outer diameter is 0.18% at the second halfway stop, 0.18% at the third halfway stop, 0.35% at the fourth halfway stop, It is 0.71% at the fifth break, 0.88% at the sixth break, 1.06% at the seventh break, and 2.48% at break. In addition, these swelling rates were calculated | required according to following Formula (1).
　膨出率（％）＝（外径の測定値－初期外径）／初期外径×１００・・・（１） Bulging rate (%) = (measured value of outer diameter−initial outer diameter) / initial outer diameter × 100 (1)
　図５は、以上の測定結果に基づき作成された、寿命比と膨出率の関係を表す検量線のグラフである。同図に示すように、この検量線２１は、原点（（寿命比，膨出率）＝（０，０））を通るように指数近似を行った検量線である。 FIG. 5 is a calibration curve graph created based on the above measurement results and showing the relationship between the life ratio and the bulging rate. As shown in the figure, the calibration curve 21 is a calibration curve that is exponentially approximated so as to pass through the origin ((life ratio, bulging rate) = (0, 0)).
　次に、このようにして作成された検量線に基づき配管の余寿命を推定する方法について、図１Ｂのフローチャートを参照しつつ説明する。 Next, a method for estimating the remaining life of piping based on the calibration curve created in this way will be described with reference to the flowchart of FIG. 1B.
　同図に示すように、まず実機の配管の外径を測定する（Ｓ７）。例えば、図６に示すように軸方向に所定長さを有する略円筒形の配管３０の場合、最も強い応力を受けると思われる軸方向中央部の断面３１（Ｒ－Ｓ）における外径φ３０を測定する。この測定でも、第１方向の外径（外径φ３０A）の長さと、第１方向と直交する第２方向の外径（外径φ３０B）の長さを測定し、大きい方を配管３０の外径値として取得する。なお、外径値の取得は、運用前（加熱及び加圧前）及び運用中（定期点検時等）のそれぞれで行う。また、外径の測定回数は本例のように２回に限らず何回でもよく、また外径の測定方向も直交する方向でなく、任意の方向でよい。 As shown in the figure, first, the outer diameter of the actual pipe is measured (S7). For example, as shown in FIG. 6, in the case of a substantially cylindrical pipe 30 having a predetermined length in the axial direction, the outer diameter φ 30 at the cross section 31 (RS) in the central portion in the axial direction that seems to receive the strongest stress. Measure. Also in this measurement, the length of the outer diameter in the first direction (outer diameter φ 30A ) and the length of the outer diameter in the second direction (outer diameter φ 30B ) orthogonal to the first direction are measured, and the larger one is the pipe 30. Obtained as the outer diameter value of. The outer diameter value is acquired before operation (before heating and pressurization) and during operation (during regular inspection, etc.). Further, the number of times of measurement of the outer diameter is not limited to two as in this example, and may be any number, and the measurement direction of the outer diameter is not a perpendicular direction but may be an arbitrary direction.
　次に、外径の測定値とＳ６で作成した検量線に基づき、配管の余寿命を推定する（図１ＢのＳ８）。すなわち、運用前における配管３０の初期外径値と運用中における配管３０の外径値に基づいて膨出率を算出する。そして、算出した膨出率を試験体１０で作成した検量線にあてはめる。図５に示す例では、膨出率がＢ１であった場合には、膨出率がＢの時の検量線２１の寿命比、すなわちＬ１が寿命比となる。 Next, the remaining life of the pipe is estimated based on the measured value of the outer diameter and the calibration curve created in S6 (S8 in FIG. 1B). That is, the bulging rate is calculated based on the initial outer diameter value of the pipe 30 before operation and the outer diameter value of the pipe 30 during operation. Then, the calculated bulging rate is applied to a calibration curve created with the test body 10. In the example shown in FIG. 5, when the swelling rate was B 1 represents, calibration curve 21 the life ratio of the time of the bulging ratio is B, ie L 1 becomes life ratio.
　以上に説明したように、本実施形態の余寿命の推定方法では、配管の試験体１０を加熱し内圧を加える内圧クリープ試験を行うことにより、直径方向に膨出した試験体１０の外径の測定値と寿命比との間の関係を表す検量線を作成することで、ベイナイト組織を有する配管の余寿命を正確に推定することができる。 As described above, in the method for estimating the remaining life of the present embodiment, the outer diameter of the test body 10 swelled in the diametric direction is obtained by performing an internal pressure creep test in which the pipe test body 10 is heated and an internal pressure is applied. By creating a calibration curve representing the relationship between the measured value and the life ratio, the remaining life of the pipe having a bainite structure can be accurately estimated.
　また、ベイナイト組織を有する配管では、外径が大きいほどクリープ損傷が進行していると考えられることから、異なる方向から複数回測定した測定値のうち最大値を外径の値とすることで、クリープ損傷による寿命時期を正確に予測することができる。 In addition, in a pipe having a bainite structure, it is considered that creep damage progresses as the outer diameter increases, so by setting the maximum value of the measured values measured multiple times from different directions as the value of the outer diameter, The life time due to creep damage can be accurately predicted.
　また、配管の試験体１０の膨出量を、膨出率（熱及び内圧を加える前の外径値に対する割合）に基づき算出することにより、この膨出量は配管の初期外径の長さに依存しないパラメータとなる。したがって、このようなパラメータに基づき作成した検量線は、試験体とサイズの異なる（外径の異なる）配管の余寿命推定にも用いることができる。例えば試験体１０より大型の実機に対してもこの検量線を適用することができる。 Further, by calculating the bulge amount of the test specimen 10 of the pipe based on the bulge rate (ratio to the outer diameter value before applying heat and internal pressure), this bulge amount is the length of the initial outer diameter of the pipe. This parameter does not depend on. Therefore, the calibration curve created based on such parameters can also be used to estimate the remaining life of piping having a different size (different outer diameter) from that of the specimen. For example, this calibration curve can be applied to an actual machine larger than the test body 10.
＜第２実施形態＞
　本発明者らは、ベイナイト組織を有する配管に亀裂が発生している場合は、その亀裂のうち最大の長さを有する亀裂の長さが、余寿命と相関関係にあることを見出した。そこで、本発明者らは、第１実施形態で説明したような、膨出量と余寿命の関係に係る検量線に加え、亀裂の最大長さと余寿命の関係に係る検量線を作成し、これら２つの検量線を用いて配管の余寿命を推定する方法を着想した。 Second Embodiment
The present inventors have found that when a pipe having a bainite structure is cracked, the length of the crack having the maximum length among the cracks is correlated with the remaining life. Therefore, the present inventors create a calibration curve related to the relationship between the maximum length of cracks and the remaining life in addition to the calibration curve related to the relationship between the bulging amount and the remaining life as described in the first embodiment, A method for estimating the remaining life of piping using these two calibration curves was conceived.
　図７Ａ及び図７Ｂは、本実施形態に係る余寿命の推定方法を示すフローチャートである。このうち図７Ａは、検量線を作成する手順を示すフローチャートである。また、図７Ｂは、検量線に基づき配管の余寿命を推定する手順を示すフローチャートである。 7A and 7B are flowcharts showing the remaining life estimation method according to the present embodiment. Among these, FIG. 7A is a flowchart which shows the procedure which produces a calibration curve. FIG. 7B is a flowchart showing a procedure for estimating the remaining life of the pipe based on the calibration curve.
　まず、検量線を作成する手順について説明する。図７Ａのフローチャートに示すように、検量線を作成するに際し、まず第１実施形態と同様の内圧クリープ試験を行う（Ｓ１１）。 First, the procedure for creating a calibration curve will be described. As shown in the flowchart of FIG. 7A, when creating a calibration curve, first, an internal pressure creep test similar to that of the first embodiment is performed (S11).
　この第２実施形態では、第１実施形態で説明した外径の測定に加え、試験体１０の表面に亀裂が発生しているか否かを判定する。そして、亀裂が発生している場合には、その亀裂の長さを測定する。なお、亀裂が複数発生している場合はその最大値を測定する。便宜上、以下の説明では、１つしか発生していない亀裂の長さと、複数発生している亀裂のうちの最大値とをまとめて「最大亀裂長さ」という。 In the second embodiment, in addition to the measurement of the outer diameter described in the first embodiment, it is determined whether or not a crack has occurred on the surface of the test body 10. And when the crack has generate | occur | produced, the length of the crack is measured. In addition, when multiple cracks have occurred, the maximum value is measured. For convenience, in the following description, the length of only one crack and the maximum value among the plurality of cracks are collectively referred to as “maximum crack length”.
　そして、Ｓ１２～Ｓ１６に示すように、試験体１０が破断していない限り（Ｓ１２：ＮＯ）、所定の測定タイミングが到来した時点で（Ｓ１３：ＹＥＳ）、試験体１０の外径を測定し（Ｓ１４）。この際試験体１０に亀裂が発生している場合は（Ｓ１５：ＹＥＳ）、その最大亀裂長さを測定する（Ｓ１６）。その後はＳ１２に戻る。試験体１０が破断した場合は（Ｓ１２：ＹＥＳ）、その時点で試験体１０の外径、及び最大亀裂長さを測定し（Ｓ１７、Ｓ１８）、後述する検量線の作成に進む（Ｓ１９）。 Then, as shown in S12 to S16, as long as the specimen 10 is not broken (S12: NO), the outer diameter of the specimen 10 is measured when a predetermined measurement timing arrives (S13: YES) ( S14). At this time, if a crack has occurred in the specimen 10 (S15: YES), the maximum crack length is measured (S16). Thereafter, the process returns to S12. When the test body 10 is broken (S12: YES), the outer diameter and the maximum crack length of the test body 10 are measured at that time (S17, S18), and the process proceeds to the creation of a calibration curve described later (S19).
　なお、試験体１０に亀裂が生じているか否かの判定は、例えば、走査型電子顕微鏡（ＳＥＭ：Scanning Electron Microscope）による組織観察によって行う。この組織観察は、試験体１０における所定の範囲に対して行い、例えば外径を測定した位置（例えば軸方向中央部）における所定範囲とする。また、この所定範囲の広さは任意であるが、例えば０．３ｍｍ２～１．０ｍｍ２である。 Note that whether or not the test body 10 has cracks is determined by, for example, observing the structure with a scanning electron microscope (SEM). This tissue observation is performed on a predetermined range in the test body 10, for example, a predetermined range at a position where the outer diameter is measured (for example, the central portion in the axial direction). Further, the width of the predetermined range is arbitrary, but is, for example, 0.3 mm 2 to 1.0 mm 2 .
　Ｓ１９では、外径や最大亀裂長さの測定値に基づき、膨出率と寿命比の関係を表す検量線と、最大亀裂長さと寿命比の関係を表す検量線とを作成する。 In S19, based on the measured values of the outer diameter and the maximum crack length, a calibration curve representing the relationship between the bulging rate and the life ratio and a calibration curve representing the relationship between the maximum crack length and the life ratio are created.
　図８及び図９に示すように、第２実施形態では、外径が異なる２つの試験体１０（試験体ａ、試験体ｂ）を用いて内圧クリープ試験を行った。試験体ａによる試験は第１実施形態と同じ試験体１０による試験である。試験体ｂによる試験は、初期外径φ１０が５６．６ｍｍの試験体１０による試験であり、この試験条件は、加熱温度が５５０℃、内圧が１４５ＭＰａである。 As shown in FIGS. 8 and 9, in the second embodiment, an internal pressure creep test was performed using two test bodies 10 (test body a and test body b) having different outer diameters. The test using the test specimen a is a test using the same test specimen 10 as in the first embodiment. The test by the test body b is a test by the test body 10 having an initial outer diameter φ 10 of 56.6 mm. The test conditions are a heating temperature of 550 ° C. and an internal pressure of 145 MPa.
　次に、試験結果について説明する。図１０及び図１１は、試験体ａの試験結果をまとめた図である。このうち図１０は外径の測定結果であり、図４と同様なので説明を省略する。図１１は、試験体ａの最大亀裂長さの結果を示す図である。 Next, the test results will be described. FIG.10 and FIG.11 is the figure which put together the test result of the test body a. Of these, FIG. 10 shows the measurement result of the outer diameter, which is the same as FIG. FIG. 11 is a diagram showing the results of the maximum crack length of the test body a.
　図１１に示すように、試験体ａに亀裂の発生が確認されたのは第６回中途止め（６４００時間後）、７１９５時間後（第７回中途止め）、及び試験体ａの破断時（８４３７時間後）であり、その際に測定された最大亀裂長さはそれぞれ、５１８μｍ、１．０９ｍｍ、１８．１ｍｍであった。なお、試験体ａの膨出率は第１実施形態と同様である（第２回中途止めでは０．１８％、第３回中途止めでは０．１８％、第４回中途止めでは０．３５％、第５回中途止めでは０．７１％、第６回中途止めでは０．８８％、第７回中途止めでは１．０６％、破断時では２．４８％）。 As shown in FIG. 11, the occurrence of cracks in the test specimen a was confirmed at the sixth stop (6400 hours later), after 7195 hours (seventh stop), and when the test specimen a was broken ( 8437 hours later), and the maximum crack lengths measured at that time were 518 μm, 1.09 mm, and 18.1 mm, respectively. The bulging rate of the specimen a is the same as in the first embodiment (0.18% for the second halfway stop, 0.18% for the third halfway stop, and 0.35 for the fourth halfway stop. %, 0.71% at the 5th stop, 0.88% at the 6th stop, 1.06% at the 7th stop, 2.48% at break).
　図１２に、第６回中途止め時における試験体ａのＳＥＭの像を示す。同図に示すように、試験体ａには亀裂４１及び亀裂４２が発生しているが、亀裂４１及び亀裂４２の間が寸断されている。このように、最大亀裂長さの測定範囲において亀裂が寸断されている場合は、寸断されている箇所の長さが、その寸断箇所が隣接する両亀裂のうち長い方の長さに対して所定の割合以下であれば、これら両亀裂及び寸断箇所は繋がった一つの亀裂であるとみなして、亀裂の長さを求めた。 FIG. 12 shows an SEM image of the specimen a at the time of the sixth suspension. As shown in the figure, the test body a has cracks 41 and 42, but the gap between the cracks 41 and 42 is broken. Thus, when a crack is cut in the measurement range of the maximum crack length, the length of the cut portion is predetermined with respect to the longer length of both cracks adjacent to the cut portion. If the ratio is less than or equal to the above, the crack length was determined by regarding that both cracks and the cut-off portion were one connected crack.
　すなわち、亀裂が途中で寸断されている場合、寸断されている箇所が今後亀裂になるか否かは、この寸断箇所が隣接している両亀裂のうち長い方の亀裂から強い影響を受けると考えられる。そして、長い方の長さに対して寸断箇所の長さが所定の割合以下である場合には、この寸断箇所が今後亀裂になりやすいと評価できると考えられる。 In other words, if a crack is broken in the middle, whether or not the cut portion will become a crack in the future is considered to be strongly influenced by the longer of the two adjacent cracks. It is done. If the length of the cut portion is equal to or less than a predetermined ratio with respect to the longer length, it can be evaluated that the cut portion is likely to crack in the future.
　そこで、上記のように寸断箇所の長さが亀裂に対して短い場合には寸断箇所をも亀裂の一部とみなすことにより、クリープ余寿命を精度良く予測できる検量線を作成することができると考えられる。このことから、上記所定の割合は、例えば半分であることが好ましく、４割であることがより好ましく、３割であることがさらに好ましい。 Therefore, when the length of the cut portion is short relative to the crack as described above, it is possible to create a calibration curve that can accurately predict the remaining creep life by considering the cut portion as a part of the crack. Conceivable. From this, the predetermined ratio is preferably, for example, half, more preferably 40%, and still more preferably 30%.
　図１２の例では、寸断されている箇所の長さ４３が、亀裂４１、亀裂４２のうち長い方の亀裂４１の長さの半分以下であることから、亀裂４１及び亀裂４２は寸断箇所も含めて一つの亀裂であるとみなし、その亀裂長さを５１８μｍとした。 In the example of FIG. 12, since the length 43 of the cut portion is not more than half of the length of the longer crack 41 of the crack 41 and the crack 42, the crack 41 and the crack 42 include the cut portion. The crack length was 518 μm.
　なお、亀裂の長さとは、亀裂の両端を結んだ直線の長さであり、また、寸断されている箇所の長さとは、寸断されている箇所とこの寸断箇所が隣接する両亀裂とが作る２つの交点間の直線の長さである。また、亀裂の長さを測定する方法は、特に限定されず、公知の方法を用いることができるが、例えば、走査型電子顕微鏡によって表面の組織観察を行うことによって測定する。 The length of the crack is the length of a straight line connecting both ends of the crack, and the length of the part that is cut off is formed by the part that is cut off and the two cracks adjacent to the cut part. The length of a straight line between two intersections. Moreover, the method of measuring the length of a crack is not specifically limited, A well-known method can be used, For example, it measures by performing surface structure | tissue observation with a scanning electron microscope.
　図１３には、試験体ｂの外径の測定結果を示す。同図に示すように、試験体ｂの外径の測定は、熱及び内圧を加え始めてから１５００時間後（第２回中途止め）、２１００時間後（第３回中途止め）、４０００時間後（第４回中途止め）、５５６２時間後（第５回中途止め）、６４００時間後（第６回中途止め）、及び６５０７時間後（試験体ｂの破断時）に行った。これらの外径から算出される膨出率は、第２回中途止めで０．００％、第３回中途止めで０．００％、第４回中途止めで０．００％、第５回中途止めで０．５３％、第６回中途止めで０．７１％、破断時で０．７１％であった。なお、第１実施形態と同様にこれらの測定タイミングにおける寿命比を求めると、第２回中途止めでの寿命比は０．２３、第３回中途止めでの寿命比は０．３２、第４回中途止めでの寿命比は０．６１、第５回中途止めでの寿命比は０．８５、第６回中途止めでの寿命比は０．９８、破断時の寿命比は１．００である。 FIG. 13 shows the measurement result of the outer diameter of the specimen b. As shown in the figure, the measurement of the outer diameter of the test specimen b is 1500 hours after the start of application of heat and internal pressure (second suspension), 2100 hours (third suspension), and 4000 hours later ( 4th stoppage), after 5562 hours (5th stoppage), after 6400 hours (6th stoppage), and after 6507 hours (when the specimen b was broken). The bulging rate calculated from these outer diameters is 0.00% for the second halfway stop, 0.00% for the third halfway stop, 0.00% for the fourth halfway stop, and the fifth halfway. It was 0.53% at the stop, 0.71% at the sixth stop, and 0.71% at break. When the life ratio at these measurement timings is obtained as in the first embodiment, the life ratio at the second halfway stop is 0.23, the life ratio at the third halfway stop is 0.32, and the fourth The life ratio at the middle stop is 0.61, the life ratio at the fifth halfway stop is 0.85, the life ratio at the sixth halfway stop is 0.98, and the life ratio at break is 1.00. is there.
　図１４には、試験体ｂの最大亀裂長さの測定結果を示す。同図に示すように、試験開始から５５６２時間後（第５回中途止め）における最大亀裂長さは７６４μｍ、試験開始から６４００時間後（第６回中途止め）における最大亀裂長さは３．４１ｍｍ、破断時（試験開始から６５０７時間後）における最大亀裂長さは２３．７ｍｍであった。 FIG. 14 shows the measurement result of the maximum crack length of the specimen b. As shown in the figure, the maximum crack length after 5562 hours from the start of the test (fifth stop) is 764 μm, and the maximum crack length after 6400 hours from the start of the test (sixth stop) is 3.41 mm. The maximum crack length at the time of rupture (after 6507 hours from the start of the test) was 23.7 mm.
　なお、図１３、図１４に示すように、試験体ｂの外径及び最大亀裂長さの測定間隔は第１実施形態と同様に約５００時間～約２０００時間であり、平均すると約１０００時間である。 As shown in FIGS. 13 and 14, the measurement interval of the outer diameter and the maximum crack length of the specimen b is about 500 hours to about 2000 hours as in the first embodiment, and averages about 1000 hours. is there.
　図１５は、以上の試験結果に基づき作成された、膨出率と寿命比の関係を示す検量線５１である。同図に示すように、この検量線５１では、原点を通るように指数近似を行った。一方、図１６は、最大亀裂長さと寿命比検量線の関係を示す検量線６１である。同図に示すように、この検量線６１も原点を通るように指数近似を行った。 FIG. 15 is a calibration curve 51 created based on the above test results and showing the relationship between the bulging rate and the life ratio. As shown in the figure, the calibration curve 51 is exponentially approximated so as to pass through the origin. On the other hand, FIG. 16 is a calibration curve 61 showing the relationship between the maximum crack length and the life ratio calibration curve. As shown in the figure, exponential approximation was performed so that the calibration curve 61 also passes through the origin.
　次に、これら２つの検量線に基づく余寿命の推定手順を、図７Ｂのフローチャートに参照しつつ説明する。 Next, the remaining life estimation procedure based on these two calibration curves will be described with reference to the flowchart of FIG. 7B.
　同図に示すように、余寿命の推定に際しては、まず実機の配管に亀裂が発生しているか否かを判定する（Ｓ２１）。この亀裂の発生の判定は、例えば、走査型電子顕微鏡（ＳＥＭ）による組織観察によって行う。組織観察の範囲は、例えば、クリープ損傷を受けやすい部位（例えば配管中央部）に設定した所定範囲（０．３ｍｍ２～１．０ｍｍ２）とする。 As shown in the figure, when estimating the remaining life, it is first determined whether or not there is a crack in the piping of the actual machine (S21). The determination of the occurrence of this crack is made, for example, by observing the structure with a scanning electron microscope (SEM). The range of the tissue observation is, for example, a predetermined range (0.3 mm 2 to 1.0 mm 2 ) set at a site susceptible to creep damage (for example, the central portion of the pipe).
　実機の配管に亀裂が発生していると判定した場合には（Ｓ２１：ＹＥＳ）、実機の配管の最大亀裂長さを測定する（Ｓ２２）。具体的には、例えばＳ２１で組織観察を行った範囲における最大亀裂長さを測定する。 When it is determined that a crack has occurred in the actual pipe (S21: YES), the maximum crack length of the actual pipe is measured (S22). Specifically, for example, the maximum crack length in the range where the structure is observed in S21 is measured.
　そして、測定した最大亀裂長さを、最大亀裂長さと寿命比検量線の関係を示す検量線６１にあてはめ（Ｓ２３）、配管の余寿命を推定する（Ｓ２４）。図１６の例では、実機の最大亀裂長さがＣ３であるので、最大亀裂長さがＣ３の時の検量線６１の寿命比、すなわちＬ３が寿命比となる。 Then, the measured maximum crack length is fitted to a calibration curve 61 indicating the relationship between the maximum crack length and the life ratio calibration curve (S23), and the remaining life of the pipe is estimated (S24). In the example of FIG. 16, the maximum crack length in actual use is a C 3, the life ratio of the calibration curve 61 at the maximum crack length is C3, i.e. L 3 becomes life ratio.
　一方、実機の配管に亀裂が発生していないと判定した場合には（図７ＢのＳ２１：ＮＯ）、実機の配管の外径を測定する（Ｓ２５）。例えば、クリープ損傷を受けやすい配管中央部の外径を測定する。 On the other hand, when it is determined that there is no crack in the actual machine pipe (S21: NO in FIG. 7B), the outer diameter of the actual machine pipe is measured (S25). For example, the outer diameter of the central part of a pipe that is susceptible to creep damage is measured.
　そして、測定した外径を、膨出率と寿命比の関係を表す検量線５１にあてはめ（Ｓ２６）、配管の余寿命を推定する（Ｓ２７）。具体的には、測定した外径値から膨出率を求め、求めた膨出率から膨出率－寿命比検量線を作成して配管の寿命比を求める。図１５の例では、実機の膨出率がＢ２であるので、膨出率がＢ２の時の検量線５１の寿命比、すなわちＬ２が寿命比となる。 Then, the measured outer diameter is applied to a calibration curve 51 representing the relationship between the bulging rate and the life ratio (S26), and the remaining life of the pipe is estimated (S27). Specifically, the bulging rate is obtained from the measured outer diameter value, and a bulging rate-life ratio calibration curve is created from the obtained bulging rate to obtain the life ratio of the pipe. In the example of FIG. 15, since the actual bulging ratio is B 2, bulging rate life ratio of the calibration curve 51 when the B 2, i.e. L 2 is life ratio.
　このように、本実施形態の配管の余寿命の推定方法では、最大亀裂長さと余寿命との関係を表す検量線を作成しておき、配管に亀裂が発生している場合は、最大亀裂長さと余寿命との関係を表す検量線と、最大亀裂長さの実測値とに基づき配管の余寿命を推定することで、ベイナイト組織を有する配管の余寿命を正確に推定することができる。 As described above, in the method for estimating the remaining life of the pipe according to the present embodiment, a calibration curve representing the relationship between the maximum crack length and the remaining life is prepared, and if a crack has occurred in the pipe, the maximum crack length is By estimating the remaining life of the pipe based on the calibration curve representing the relationship between the life and the remaining life and the actual measured value of the maximum crack length, it is possible to accurately estimate the remaining life of the pipe having the bainite structure.
　以上の実施形態の説明は、本発明の理解を容易にするためのものであり、本発明を限定するものではない。本発明はその趣旨を逸脱することなく、変更、改良され得ると共に本発明にはその等価物が含まれる。 The above description of the embodiment is intended to facilitate understanding of the present invention and does not limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes equivalents thereof.
１０　試験体、１１　管部材、１２　第１栓部材、１３　第２栓部材、１４　注入管、１５　高温流体、１６　断面、２１　検量線　３０　配管、３１　断面、４１　亀裂、４２　亀裂、４３　寸断されている箇所の長さ、５１　検量線、６１　検量線
  10 Specimens, 11 Tube member, 12 First plug member, 13 Second plug member, 14 Injection tube, 15 High temperature fluid, 16 Cross section, 21 Calibration curve 30 Pipe, 31 Cross section, 41 Crack, 42 Crack, 43 Cut down Length of the location, 51 calibration curve, 61 calibration curve

Claims (4)

  1. 　加熱及び加圧によりクリープ損傷を受ける、ベイナイト組織を有する円筒形状の配管の余寿命を検量線を用いて推定する方法であって、
    　材質が前記配管と同一の、中空の試験体に熱及び内圧を加えて外径を測定し、
    　所定時間をおいて前記外径の測定を複数回行うことにより、前記試験体の直径方向の膨出率と前記試験体の余寿命との関係を示す検量線を作成し、
    　前記配管の外径を測定することで、前記配管の直径方向の膨出率を求め、
    　前記配管の膨出率と前記検量線とに基づき、前記配管の余寿命を推定することを特徴とする、ベイナイト組織を有する配管の余寿命を検量線を用いて推定する方法。     A method for estimating the remaining life of a cylindrical pipe having a bainite structure, which is damaged by heating and pressurization, using a calibration curve,
    Measure the outer diameter by applying heat and internal pressure to a hollow test body with the same material as the pipe,
    A calibration curve indicating the relationship between the bulging rate in the diameter direction of the test specimen and the remaining life of the test specimen is created by performing the measurement of the outer diameter a plurality of times at a predetermined time,
    By measuring the outer diameter of the pipe, find the bulge rate in the diameter direction of the pipe,
    A method for estimating the remaining life of a pipe having a bainite structure using a calibration curve, wherein the remaining life of the pipe is estimated based on the bulging rate of the pipe and the calibration curve.
  2. 　前記試験体の外径は、異なる方向から複数回測定された外径の最大値であり、
    　前記配管の外径は、異なる方向から複数回測定された前記配管の外径の最大値であることを特徴とする、請求項１に記載のベイナイト組織を有する配管の余寿命を検量線を用いて推定する方法。     The outer diameter of the specimen is the maximum value of the outer diameter measured multiple times from different directions,
    The calibration curve for the remaining life of a pipe having a bainite structure according to claim 1, wherein the outer diameter of the pipe is a maximum value of the outer diameter of the pipe measured a plurality of times from different directions. To estimate.
  3. 　前記試験体の膨出率は、前記熱及び内圧を加える前の前記試験体の外径に対する、前記熱及び内圧を加えた後の前記試験体の外径の比であることを特徴とする、請求項１又は２に記載のベイナイト組織を有する配管の余寿命を検量線を用いて推定する方法。 The swelling rate of the test body is a ratio of the outer diameter of the test body after applying the heat and internal pressure to the outer diameter of the test body before applying the heat and internal pressure, A method for estimating a remaining life of a pipe having a bainite structure according to claim 1 or 2 using a calibration curve.
  4. 　前記試験体の外径を測定する際には、前記試験体に亀裂が発生しているか否かも判定し、亀裂が発生していると判定した場合には、
    　　前記発生している亀裂のうち最大の長さを有する亀裂の長さを測定し、
    　　測定した前記試験体の亀裂の長さと前記試験体の余寿命との関係を示す他の検量線を作成し、
    　前記配管の外径を測定する際には、前記配管に亀裂が発生しているか否かも判定し、亀裂が発生している判定した場合には、
    　　前記配管に存在する亀裂のうち最大の長さを有する亀裂の長さを測定し、
    　　測定した前記配管の亀裂の長さと前記他の検量線とに基づき、前記配管の余寿命を推定することを特徴とする、請求項１乃至３のいずれか一項に記載のベイナイト組織を有する配管の余寿命を検量線を用いて推定する方法。     When measuring the outer diameter of the specimen, it is also determined whether or not a crack has occurred in the specimen, and if it is determined that a crack has occurred,
    Measure the length of the crack having the maximum length among the cracks that have occurred,
    Create another calibration curve showing the relationship between the measured crack length of the specimen and the remaining life of the specimen,
    When measuring the outer diameter of the pipe, it is also determined whether a crack has occurred in the pipe, and if it is determined that a crack has occurred,
    Measure the length of the crack having the maximum length among the cracks present in the pipe,
    The pipe having a bainite structure according to any one of claims 1 to 3, wherein the remaining life of the pipe is estimated based on the measured crack length of the pipe and the other calibration curve. To estimate the remaining life of a product using a calibration curve.
PCT/JP2014/050681 2014-01-16 2014-01-16 Estimation method using calibration curve of remaining lifespan of tubing having bainite structure WO2015107652A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105277480A (en) * 2015-09-25 2016-01-27 宝鸡石油钢管有限责任公司 Coal gas conveyer pipe full-scale test evaluation method

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63157058A (en) * 1986-12-22 1988-06-30 Babcock Hitachi Kk Service life predicting method for metal member
JP2008051659A (en) * 2006-08-24 2008-03-06 Mitsubishi Heavy Ind Ltd Method for evaluating lifetime
JP2013148476A (en) * 2012-01-19 2013-08-01 Mitsubishi Heavy Ind Ltd Evaluation criterion setting method for life of piping and life evaluation method of piping

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63157058A (en) * 1986-12-22 1988-06-30 Babcock Hitachi Kk Service life predicting method for metal member
JP2008051659A (en) * 2006-08-24 2008-03-06 Mitsubishi Heavy Ind Ltd Method for evaluating lifetime
JP2013148476A (en) * 2012-01-19 2013-08-01 Mitsubishi Heavy Ind Ltd Evaluation criterion setting method for life of piping and life evaluation method of piping

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
DAISUKE ARAKAWA: "Bainite Soshiki o Yusuru Haikan no Creep Yojumyo Hyokaho Kaihatsu", ENERGIA SOKEN REVIEW, vol. 4, no. 34, 11 December 2013 (2013-12-11), pages 2 - 3 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105277480A (en) * 2015-09-25 2016-01-27 宝鸡石油钢管有限责任公司 Coal gas conveyer pipe full-scale test evaluation method

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