WO2023058086A1 - Hydrogen embrittlement risk assessment method and device therefor - Google Patents

Hydrogen embrittlement risk assessment method and device therefor Download PDF

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WO2023058086A1
WO2023058086A1 PCT/JP2021/036614 JP2021036614W WO2023058086A1 WO 2023058086 A1 WO2023058086 A1 WO 2023058086A1 JP 2021036614 W JP2021036614 W JP 2021036614W WO 2023058086 A1 WO2023058086 A1 WO 2023058086A1
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function
hydrogen embrittlement
tensile stress
average
temperature
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PCT/JP2021/036614
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French (fr)
Japanese (ja)
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拓哉 上庄
龍太 石井
昌幸 津田
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日本電信電話株式会社
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Priority to PCT/JP2021/036614 priority Critical patent/WO2023058086A1/en
Priority to JP2023552411A priority patent/JPWO2023058086A1/ja
Publication of WO2023058086A1 publication Critical patent/WO2023058086A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N17/00—Investigating resistance of materials to the weather, to corrosion, or to light

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  • the present invention relates to a method and apparatus for evaluating the hydrogen embrittlement risk of steel materials.
  • Non-Patent Document 1 the effects of hydrogen embrittlement factors such as tensile stress and temperature on the rupture time have been clarified.
  • the present invention has been made in view of this problem, and provides a hydrogen embrittlement risk evaluation method that can evaluate how the hydrogen embrittlement risk of steel materials changes due to changes in the values of hydrogen embrittlement factors. intended to provide
  • a hydrogen embrittlement risk evaluation method uses a tensile stress applied to a steel material at a constant temperature as a variable, and a first function representing an average fracture time due to hydrogen embrittlement of the steel material with respect to changes in the tensile stress a second function generating step of obtaining a second function representing the average rupture time by multiplying the first function with temperature as a variable; and changing the tensile stress to the first function to calculate the hydrogen embrittlement risk represented by the increase ratio of the average rupture time, input the change in temperature into the second function, and the hydrogen embrittlement risk represented by the increase ratio of the average rupture time
  • the gist is to perform a hydrogen embrittlement risk calculation step of calculating
  • the hydrogen embrittlement risk evaluation apparatus uses the tensile stress applied to a steel material at a constant temperature as a variable, and expresses the average fracture time due to hydrogen embrittlement of the steel material with respect to the change in the tensile stress.
  • a first function generation unit that obtains one function
  • a second function generation unit that obtains a second function representing the average rupture time by multiplying the first function with temperature as a variable
  • the tensile stress in the first function to calculate the hydrogen embrittlement risk represented by the increase ratio of the average rupture time, input the change in temperature into the second function
  • hydrogen embrittlement represented by the increase ratio of the average rupture time and a hydrogen embrittlement risk calculation unit that calculates a hydrogen embrittlement risk.
  • FIG. 1 is a diagram showing a functional configuration example of a hydrogen embrittlement risk assessment device according to an embodiment of the present invention
  • FIG. It is a figure which shows the relationship example of a tensile stress and an average breaking time.
  • FIG. 5 is a diagram showing an example of the relationship between temperature and average rupture time when tensile stress is used as a parameter.
  • 2 is a flow chart showing a processing procedure of a hydrogen embrittlement risk evaluation method executed by the hydrogen embrittlement risk evaluation apparatus shown in FIG. 1;
  • 1 is a block diagram showing a configuration example of a general-purpose computer system;
  • FIG. 1 is a diagram showing a functional configuration example of a hydrogen embrittlement risk assessment apparatus according to an embodiment of the present invention.
  • a hydrogen embrittlement risk evaluation apparatus 1 shown in FIG. 1 is an apparatus for evaluating how the hydrogen embrittlement risk of a steel material changes with changes in the values of hydrogen embrittlement factors.
  • the hydrogen embrittlement risk evaluation device 1 includes a first function generator 10, a second function generator 20, and a hydrogen embrittlement risk calculator 30.
  • Each functional component of the hydrogen embrittlement risk assessment apparatus 1 can be realized by a computer including, for example, a ROM, a RAM, and a CPU.
  • the first function generation unit 10 uses the tensile stress applied to the steel material at a constant temperature as a variable, and obtains the first function representing the average fracture time due to hydrogen embrittlement of the steel material with respect to the change in the tensile stress.
  • the steel material is, for example, reinforcing bars for prestressed concrete. Henceforth, the wording of reinforcing bars will not be used and will be standardized to steel materials.
  • the tensile stress applied to the steel material is the tensile stress applied to the steel material for the purpose of measuring the time for the steel material to break due to hydrogen embrittlement.
  • An accelerated test for measuring the rupture time due to hydrogen embrittlement is repeatedly performed using the temperature T [K] of the steel material as a parameter, and the first function representing the average rupture time due to hydrogen embrittlement is obtained.
  • FIG. 2 is a diagram showing an example of the relationship between the tensile stress S and the average breaking time tave .
  • the horizontal axis of FIG. 2 is the logarithmic value of the tensile stress S (ln(S)), and the vertical axis is the logarithmic value of the average breaking time t ave (ln(t ave )).
  • the parameters of the relational example shown in FIG. 2 are three types of temperature 283K ( ⁇ ), 298K ( ⁇ ), and 308K ( ⁇ ). Also, each plot is the average of 10 rupture times.
  • the relationship between the logarithmic value (ln(S)) and the logarithmic value (ln(t ave )) is linear. Moreover, the slope of the straight line is approximately constant even if the value of the parameter temperature T is changed.
  • the first function generation unit 10 obtains the equation (1) representing the change in the average rupture time t- ave with respect to the tensile stress S from the respective values of the tensile stress S and the average rupture time t- ave . Equation (1) can be easily obtained by the method of least squares.
  • a is the slope of the straight line shown in FIG. 2
  • g'(T) is the offset amount of the straight line.
  • g'(T) is a function that depends only on temperature.
  • the first function generator 10 obtains the first function Sa having the tensile stress S as a variable by inverse logarithmically transforming the slope a of the straight line.
  • the second function generator 20 uses the temperature T as a variable and multiplies the first function S a to obtain the second function g(T) representing the average rupture time t ave . That is, the second function generator 20 generates a breakage time function (equation (2)) that expresses the average breakage time t ave by the product of the first function Sa and the second function exp(g'(t)).
  • the first function is f(S)
  • the second function is g(T)
  • S is the tensile stress
  • T is the temperature
  • the average breaking time t ave is It is represented by the following formula.
  • the hydrogen embrittlement risk calculation unit 30 inputs the change in the tensile stress S to the first function f(S) to calculate the hydrogen embrittlement risk represented by the increase ratio of the average rupture time, and the second function g( The change in temperature T is input to T) to calculate the hydrogen embrittlement risk represented by the increase ratio of the average rupture time.
  • the first function f(S) can be expressed by the following equation since the slope of the straight line is about -3.6.
  • the average breaking time tave is 0.23 times. That is, S(900 MPa)/S(600 MPa) ⁇ 0.23. If the temperature T is the same, the value of the second function g(T) is ignored.
  • the change from 600 MPa to 900 MPa is an example of the change in the tensile stress S.
  • a plurality of tensile stress values are input to the first function f(S).
  • FIG. 3 is a diagram showing an example of the relationship between temperature and average rupture time when tensile stress is used as a parameter.
  • the horizontal axis of FIG. 3 is the temperature T, and the vertical axis is the average rupture time tave .
  • the parameter tensile stress is 994 MPa.
  • the second function g(T) can be obtained by t ave /994 -3.6 . Therefore, the second function g(T) can be obtained by dividing each average breaking time t ave shown in FIG. 3 by 994 ⁇ 3.6 and performing fitting using numerical calculation.
  • the second function g(T) can be expressed by, for example, the following equation.
  • the increase ratio of the average rupture time t ave when, for example, 298 K ⁇ 308 K is input as the change in temperature T into the second function shown in Equation (5) is g(308)/g(298) ⁇ 1.85, indicating the rate of hydrogen embrittlement. It can be seen that the relative risk is reduced to 1/1.85 ⁇ 0.54 times.
  • 298K and 308K are examples of changes in the temperature T input to the second function g(T).
  • multiple temperatures T are input to the second function g(T).
  • the relative risk means the risk when the tensile stress S is constant and the temperature T is changed, or when the temperature T is constant and the tensile strength S is changed. It is also possible to evaluate the relative risk when both the tensile stress S and the temperature T change. For example, when the tensile stress S increases from 600 MPa to 900 MPa and the temperature T increases from 298 K to 308 K, the increase ratio of the average breaking time tave is, for example, S (900) / S (600) ⁇ g (308) /g(298) ⁇ 0.43, and the relative risk of hydrogen embrittlement increases 1/0.43 ⁇ 2.33 times.
  • the hydrogen embrittlement risk evaluation apparatus 1 uses the tensile stress applied to the steel material at a constant temperature T as a variable, and the average fracture time due to hydrogen embrittlement of the steel material with respect to the change in the tensile stress
  • a first function generation unit 10 that obtains a first function f (S) that represents the temperature T, and a second function g (T) that represents the average rupture time t ave by multiplying the first function f (S) with the temperature T as a variable and the change in the tensile stress S to the first function f(S) to calculate the hydrogen embrittlement risk represented by the increase ratio of the average rupture time tave
  • the second function a hydrogen embrittlement risk calculator 30 for calculating the hydrogen embrittlement risk represented by the increase ratio of the average rupture time t ave by inputting the temperature change to g(T).
  • FIG. 4 is a flow chart showing the processing procedure of the hydrogen embrittlement risk assessment method executed by the hydrogen embrittlement risk assessment device 1 (FIG. 1). A hydrogen embrittlement risk evaluation method will be described with reference to FIG.
  • the first function generation unit 10 sets the tensile stress S applied to the steel material at a constant temperature T as a variable, and determines the hydrogen embrittlement of the steel material with respect to the change in the tensile stress S.
  • a first function generation step S1 is performed to obtain a first function f(S) representing the average rupture time t ave by .
  • the second function generation unit 20 performs a second function generation step S2 to obtain a second function g(T) representing the average rupture time t ave by multiplying the first function f(S) with the temperature T as a variable. conduct.
  • the hydrogen embrittlement risk calculation unit 30 inputs the change in the tensile stress S to the first function f(S) to calculate the hydrogen embrittlement risk represented by the increase ratio of the average rupture time t ave .
  • a hydrogen embrittlement risk calculation step S3 is performed for calculating the hydrogen embrittlement risk represented by the increase ratio of the average rupture time tave by inputting the change in the temperature T into the function g(T).
  • the tensile stress S applied to a steel material at a constant temperature T is used as a variable, and the average fracture time tave due to hydrogen embrittlement of the steel material with respect to changes in the tensile stress S is A first function generating step S1 for obtaining a first function f(S) representing the The second function generation step S2 to be obtained and the change in the tensile stress S are input to the first function f(S) to calculate the hydrogen embrittlement risk represented by the increase ratio of the average rupture time tave , and the second function g
  • a hydrogen embrittlement risk calculation step S3 is performed for calculating the hydrogen embrittlement risk represented by the increase ratio of the average rupture time tave by inputting the change in the temperature T into (T). This makes it possible to evaluate how the relative risk of hydrogen embrittlement changes depending on the values of tensile stress S and temperature T.
  • the hydrogen embrittlement risk assessment apparatus 1 can be realized by the general-purpose computer system shown in FIG. Each function of the hydrogen embrittlement risk assessment apparatus 1 is realized by the CPU 50 executing a predetermined program loaded on the memory 51 in a general-purpose computer system.
  • the prescribed program can be recorded on computer-readable recording media such as HDD, SSD, USB memory, CD-ROM, DVD-ROM, MO, etc., or can be distributed via a network.
  • the present invention is not limited to the above embodiments, and can be modified within the scope of the gist.
  • the first function f(S) regresses by the method of least squares, it may be regressed using other numerical calculations.
  • Hydrogen embrittlement risk evaluation device 10 First function generator 20: Second function generator 30: Hydrogen embrittlement risk calculator

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Abstract

The present invention involves: a first function generation step S1 for obtaining a first function f(S) which represents an average fracture time tave resulting from hydrogen embrittlement of a steel material with respect to a change in a tensile stress S applied to the steel material having a constant temperature T, and in which the tensile stress S is a variable; a second function generation step S2 for obtaining a second function g(T) which represents the average fracture time tave by being multiplied by the first function f(S), in which the temperature T is a variable; and a hydrogen embrittlement risk calculation step S3 for calculating a hydrogen embrittlement risk that is represented by an increase ratio of the average fracture time tave, by inputting a change in the tensile stress S into the first function f(S), and calculating a hydrogen embrittlement risk that is represented by an increase ratio of the average fracture time tave, by inputting a change in the temperature T into the second function g(T).

Description

水素脆化リスク評価方法とその装置Hydrogen embrittlement risk assessment method and device
　本発明は、鋼材の水素脆化リスクを評価する方法とその装置に関する。 The present invention relates to a method and apparatus for evaluating the hydrogen embrittlement risk of steel materials.
　高強度鋼材は水素を含むと延性が失われ、強度が著しく低下する。この現象は水素脆化と称される。このような鋼材の水素脆化に関し、鋼材が水素脆化により破断するまでの時間を予測し、破断時間の比較により水素脆化リスクを評価することは実用上重要である。 When high-strength steel contains hydrogen, it loses ductility and its strength drops significantly. This phenomenon is called hydrogen embrittlement. Regarding such hydrogen embrittlement of steel materials, it is practically important to estimate the time until the steel material fractures due to hydrogen embrittlement and evaluate the hydrogen embrittlement risk by comparing the fracture times.
　水素脆化による破断時間の予測には、様々な水素脆化の要因と破断時間との関係を評価する必要があり、これまでに引張応力や温度といった要因が破断時間に与える影響について調査されている（非特許文献１）。つまり、引張応力や温度といった水素脆化要因がそれぞれ単独で破断時間に与える影響は明らかになっている。 In order to predict the rupture time due to hydrogen embrittlement, it is necessary to evaluate the relationship between various hydrogen embrittlement factors and rupture time. (Non-Patent Document 1). In other words, the effects of hydrogen embrittlement factors such as tensile stress and temperature on the rupture time have been clarified.
　しかしながら、引張応力や温度等の水素脆化要因の組み合わせによって生じる相互作用は不明であった。その為、水素脆化要因の値の変化によって鋼材の水素脆化リスクがどのように変化するかを評価することができないという課題がある。 However, the interaction caused by the combination of hydrogen embrittlement factors such as tensile stress and temperature was unknown. Therefore, there is a problem that it is not possible to evaluate how the hydrogen embrittlement risk of steel materials changes due to changes in the values of hydrogen embrittlement factors.
　本発明は、この課題に鑑みてなされたものであり、水素脆化要因の値の変化によって鋼材の水素脆化リスクがどのように変化するかを評価することができる水素脆化リスク評価方法を提供することを目的とする。 The present invention has been made in view of this problem, and provides a hydrogen embrittlement risk evaluation method that can evaluate how the hydrogen embrittlement risk of steel materials changes due to changes in the values of hydrogen embrittlement factors. intended to provide
　本発明の一態様に係る水素脆化リスク評価方法は、温度が一定の鋼材に負荷する引張応力を変数とし、該引張応力の変化に対する前記鋼材の水素脆化による平均破断時間を表す第１関数を求める第１関数生成ステップと、温度を変数とし、前記第１関数に乗じることで前記平均破断時間を表す第２関数を求める第２関数生成ステップと、前記第１関数に前記引張応力の変化を入力して前記平均破断時間の増加比で表される水素脆化リスクを算出し、前記第２関数に温度の変化を入力して前記平均破断時間の増加比で表される水素脆化リスクを算出する水素脆化リスク算出ステップとを行うことを要旨とする。 A hydrogen embrittlement risk evaluation method according to an aspect of the present invention uses a tensile stress applied to a steel material at a constant temperature as a variable, and a first function representing an average fracture time due to hydrogen embrittlement of the steel material with respect to changes in the tensile stress a second function generating step of obtaining a second function representing the average rupture time by multiplying the first function with temperature as a variable; and changing the tensile stress to the first function to calculate the hydrogen embrittlement risk represented by the increase ratio of the average rupture time, input the change in temperature into the second function, and the hydrogen embrittlement risk represented by the increase ratio of the average rupture time The gist is to perform a hydrogen embrittlement risk calculation step of calculating
　また、本発明の一態様に係る水素脆化リスク評価装置は、温度が一定の鋼材に負荷する引張応力を変数とし、該引張応力の変化に対する前記鋼材の水素脆化による平均破断時間を表す第１関数を求める第１関数生成部と、温度を変数とし、前記第１関数に乗じることで前記平均破断時間を表す第２関数を求める第２関数生成部と、前記第１関数に前記引張応力の変化を入力して前記平均破断時間の増加比で表される水素脆化リスクを算出し、前記第２関数に温度の変化を入力して前記平均破断時間の増加比で表される水素脆化リスクを算出する水素脆化リスク算出部とを備えることを要旨とする。 Further, the hydrogen embrittlement risk evaluation apparatus according to one aspect of the present invention uses the tensile stress applied to a steel material at a constant temperature as a variable, and expresses the average fracture time due to hydrogen embrittlement of the steel material with respect to the change in the tensile stress. A first function generation unit that obtains one function, a second function generation unit that obtains a second function representing the average rupture time by multiplying the first function with temperature as a variable, and the tensile stress in the first function to calculate the hydrogen embrittlement risk represented by the increase ratio of the average rupture time, input the change in temperature into the second function, and hydrogen embrittlement represented by the increase ratio of the average rupture time and a hydrogen embrittlement risk calculation unit that calculates a hydrogen embrittlement risk.
　本発明によれば、水素脆化要因の値の変化によって鋼材の水素脆化リスクがどのように変化するかを評価することができる水素脆化リスク評価方法とその装置を提供することができる。 According to the present invention, it is possible to provide a hydrogen embrittlement risk evaluation method and apparatus capable of evaluating how the hydrogen embrittlement risk of steel materials changes due to changes in the values of hydrogen embrittlement factors.
本発明の実施形態に係る水素脆化リスク評価装置の機能構成例を示す図である。1 is a diagram showing a functional configuration example of a hydrogen embrittlement risk assessment device according to an embodiment of the present invention; FIG. 引張応力と平均破断時間の関係例を示す図である。It is a figure which shows the relationship example of a tensile stress and an average breaking time. 引張応力をパラメータにした場合の温度と平均破断時間の関係例を示す図である。FIG. 5 is a diagram showing an example of the relationship between temperature and average rupture time when tensile stress is used as a parameter. 図１に示す水素脆化リスク評価装置が実行する水素脆化リスク評価方法の処理手順を示すフローチャートである。2 is a flow chart showing a processing procedure of a hydrogen embrittlement risk evaluation method executed by the hydrogen embrittlement risk evaluation apparatus shown in FIG. 1; 汎用的なコンピュータシステムの構成例を示すブロック図である。1 is a block diagram showing a configuration example of a general-purpose computer system; FIG.
　以下、本発明の実施形態について図面を用いて説明する。複数の図面中同一のものには同じ参照符号を付し、説明は繰り返さない。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same reference numerals are given to the same items in multiple drawings, and the description will not be repeated.
　〔水素脆化リスク評価装置〕
　図１は、本発明の実施形態に係る水素脆化リスク評価装置の機能構成例を示す図である。図１に示す水素脆化リスク評価装置１は、水素脆化要因の値の変化によって鋼材の水素脆化リスクがどのように変化するかを評価する装置である。 [Hydrogen embrittlement risk assessment device]
FIG. 1 is a diagram showing a functional configuration example of a hydrogen embrittlement risk assessment apparatus according to an embodiment of the present invention. A hydrogen embrittlement risk evaluation apparatus 1 shown in FIG. 1 is an apparatus for evaluating how the hydrogen embrittlement risk of a steel material changes with changes in the values of hydrogen embrittlement factors.
　水素脆化リスク評価装置１は、第１関数生成部１０、第２関数生成部２０、及び水素脆化リスク算出部３０を備える。水素脆化リスク評価装置１の各機能構成部は、例えば、ＲＯＭ、ＲＡＭ、ＣＰＵ等からなるコンピュータで実現することができる。 The hydrogen embrittlement risk evaluation device 1 includes a first function generator 10, a second function generator 20, and a hydrogen embrittlement risk calculator 30. Each functional component of the hydrogen embrittlement risk assessment apparatus 1 can be realized by a computer including, for example, a ROM, a RAM, and a CPU.
　第１関数生成部１０は、温度が一定の鋼材に負荷する引張応力を変数とし、該引張応力の変化に対する鋼材の水素脆化による平均破断時間を表す第１関数を求める。ここで鋼材は、例えばプレストレスト・コンクリート用の鉄筋である。以降、鉄筋の文言は用いず鋼材に統一する。 The first function generation unit 10 uses the tensile stress applied to the steel material at a constant temperature as a variable, and obtains the first function representing the average fracture time due to hydrogen embrittlement of the steel material with respect to the change in the tensile stress. Here, the steel material is, for example, reinforcing bars for prestressed concrete. Henceforth, the wording of reinforcing bars will not be used and will be standardized to steel materials.
　また、鋼材に負荷する引張応力とは、その鋼材が水素脆化によって破断する時間を測定する目的で鋼材に負荷する引張応力のことである。鋼材の温度Ｔ［K］をパラメータとして水素脆化による破断時間を測定する加速試験を繰り返し行い、水素脆化による平均破断時間を表す第１関数を求める。 In addition, the tensile stress applied to the steel material is the tensile stress applied to the steel material for the purpose of measuring the time for the steel material to break due to hydrogen embrittlement. An accelerated test for measuring the rupture time due to hydrogen embrittlement is repeatedly performed using the temperature T [K] of the steel material as a parameter, and the first function representing the average rupture time due to hydrogen embrittlement is obtained.
　図２は、引張応力Ｓと平均破断時間ｔａｖｅの関係例を示す図である。図２の横軸は引張応力Ｓの対数値（ln(Ｓ)）であり、縦軸は平均破断時間ｔａｖｅの対数値（ln(ｔａｖｅ)）である。図２に示す関係例のパラメータは、温度283K（●）,298K（□）,308K（△）の三種類である。また、各プロットは１０個の破断時間の平均である。 FIG. 2 is a diagram showing an example of the relationship between the tensile stress S and the average breaking time tave . The horizontal axis of FIG. 2 is the logarithmic value of the tensile stress S (ln(S)), and the vertical axis is the logarithmic value of the average breaking time t ave (ln(t ave )). The parameters of the relational example shown in FIG. 2 are three types of temperature 283K (●), 298K (□), and 308K (Δ). Also, each plot is the average of 10 rupture times.
　図２に示すように、対数値（ln(Ｓ)）と対数値（ln(ｔａｖｅ)）の関係は直線の関係となる。また、パラメータの温度Ｔの値を変えても直線の傾きは凡そ一定である。 As shown in FIG. 2, the relationship between the logarithmic value (ln(S)) and the logarithmic value (ln(t ave )) is linear. Moreover, the slope of the straight line is approximately constant even if the value of the parameter temperature T is changed.
　第１関数生成部１０は、引張応力Ｓと平均破断時間ｔａｖｅのそれぞれの値から、引張応力Ｓに対する平均破断時間ｔａｖｅの変化を表す式（１）を求める。式（１）は、最小二乗法で容易に求めることができる。 The first function generation unit 10 obtains the equation (1) representing the change in the average rupture time t- ave with respect to the tensile stress S from the respective values of the tensile stress S and the average rupture time t- ave . Equation (1) can be easily obtained by the method of least squares.
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000002
　ここで、ａは図２に示す直線の傾き、ｇ′（Ｔ）は直線のオフセット量である。ｇ′（Ｔ）は、温度のみに依存する関数である。 Here, a is the slope of the straight line shown in FIG. 2, and g'(T) is the offset amount of the straight line. g'(T) is a function that depends only on temperature.
　第１関数生成部１０は、この例の場合、直線の傾きａを逆対数変換して引張応力Ｓを変数とする第１関数Ｓａを求める。 In this example, the first function generator 10 obtains the first function Sa having the tensile stress S as a variable by inverse logarithmically transforming the slope a of the straight line.
　そして、第２関数生成部２０は、温度Ｔを変数とし、第１関数Ｓａに乗じることで平均破断時間ｔａｖｅを表す第２関数ｇ（Ｔ）を求める。つまり、第２関数生成部２０は、平均破断時間ｔａｖｅを第１関数Ｓａと第２関数exp(ｇ′（ｔ）)の積で表す破断時間関数（式（２））を生成する。 Then, the second function generator 20 uses the temperature T as a variable and multiplies the first function S a to obtain the second function g(T) representing the average rupture time t ave . That is, the second function generator 20 generates a breakage time function (equation (2)) that expresses the average breakage time t ave by the product of the first function Sa and the second function exp(g'(t)).
Figure JPOXMLDOC01-appb-M000003
Figure JPOXMLDOC01-appb-M000003
　また、平均破断時間ｔａｖｅ、第１関数をｆ（Ｓ）、第２関数をｇ（Ｔ）とした場合に、ここでＳは前記引張応力、Ｔは温度であり、平均破断時間ｔａｖｅは次式で表される。 Further, when the average breaking time t ave , the first function is f(S), and the second function is g(T), where S is the tensile stress, T is the temperature, and the average breaking time t ave is It is represented by the following formula.
Figure JPOXMLDOC01-appb-M000004
Figure JPOXMLDOC01-appb-M000004
　水素脆化リスク算出部３０は、第１関数ｆ（Ｓ）に引張応力Ｓの変化を入力して平均破断時間の増加比で表される水素脆化リスクを算出し、又第２関数ｇ（Ｔ）に温度Ｔの変化を入力して平均破断時間の増加比で表される水素脆化リスクを算出する。 The hydrogen embrittlement risk calculation unit 30 inputs the change in the tensile stress S to the first function f(S) to calculate the hydrogen embrittlement risk represented by the increase ratio of the average rupture time, and the second function g( The change in temperature T is input to T) to calculate the hydrogen embrittlement risk represented by the increase ratio of the average rupture time.
　ここで、第１関数ｆ（Ｓ）は、図２に示す例の場合、直線の傾きが約-3.6であることから次式で表せる。 Here, in the example shown in FIG. 2, the first function f(S) can be expressed by the following equation since the slope of the straight line is about -3.6.
Figure JPOXMLDOC01-appb-M000005
Figure JPOXMLDOC01-appb-M000005
　例えば、引張応力Ｓが600MPaから900Mpaに増加した場合の平均破断時間ｔａｖｅは0.23倍である。つまり、Ｓ（900 MPa）/Ｓ（600 MPa）≒0.23である。温度Ｔは、同じであれば第２関数ｇ（Ｔ）の値はネグレクトされる。 For example, when the tensile stress S increases from 600 MPa to 900 MPa, the average breaking time tave is 0.23 times. That is, S(900 MPa)/S(600 MPa)≈0.23. If the temperature T is the same, the value of the second function g(T) is ignored.
　要するに、鋼材の水素脆化の温度Ｔを一定にした場合に引張応力Ｓを600MPaから900Mpaに増加した場合の平均破断時間ｔａｖｅの相対的なリスクは、1/0.23≒4.35倍に増加することが分かる。このように本実施形態によれば、水素脆化要因の値の変化によって鋼材の水素脆化リスクがどのように変化するかを評価することができる。 In short, when the hydrogen embrittlement temperature T of the steel material is kept constant, the relative risk of the average fracture time t ave increases by 1/0.23≒4.35 times when the tensile stress S is increased from 600 MPa to 900 MPa. I understand. As described above, according to the present embodiment, it is possible to evaluate how the hydrogen embrittlement risk of the steel material changes due to the change in the value of the hydrogen embrittlement factor.
　なお、600MPaから900Mpaは、引張応力Ｓの変化の一例である。上記のように、第１関数ｆ（Ｓ）に複数の引張応力の値を入力する。 　The change from 600 MPa to 900 MPa is an example of the change in the tensile stress S. As described above, a plurality of tensile stress values are input to the first function f(S).
　図３は、引張応力をパラメータにした場合の温度と平均破断時間の関係例を示す図である。図３の横軸は温度Ｔ、縦軸は平均破断時間ｔａｖｅである。パラメータの引張応力は994MPaである。 FIG. 3 is a diagram showing an example of the relationship between temperature and average rupture time when tensile stress is used as a parameter. The horizontal axis of FIG. 3 is the temperature T, and the vertical axis is the average rupture time tave . The parameter tensile stress is 994 MPa.
　この例の場合は、第１関数ｆ（Ｓ）がｆ（Ｓ）＝994-3.6であるので、第２関数ｇ（Ｔ）はｔａｖｅ/994-3.6で求めることができる。よって、第２関数ｇ（Ｔ）は、図３に示す各平均破断時間ｔａｖｅの値を994-3.6で除算し、数値計算を用いたフィッテイングにより求めることができる。第２関数ｇ（Ｔ）は、例えば次式で表せる。 In this example, since the first function f(S) is f(S)=994 -3.6 , the second function g(T) can be obtained by t ave /994 -3.6 . Therefore, the second function g(T) can be obtained by dividing each average breaking time t ave shown in FIG. 3 by 994 −3.6 and performing fitting using numerical calculation. The second function g(T) can be expressed by, for example, the following equation.
Figure JPOXMLDOC01-appb-M000006
Figure JPOXMLDOC01-appb-M000006
　式（５）に示す第２関数に温度Ｔの変化として例えば298K→308Kを入力した場合の平均破断時間ｔａｖｅの増加比はｇ（308）/ｇ（298）≒1.85となり、水素脆化の相対的なリスクは1/1.85≒0.54倍に減少することが分かる。なお、298Kと308Kは、第２関数ｇ（Ｔ）に入力する温度Ｔの変化の一例である。このように、第２関数ｇ（Ｔ）に複数の温度Ｔを入力する。 The increase ratio of the average rupture time t ave when, for example, 298 K→308 K is input as the change in temperature T into the second function shown in Equation (5) is g(308)/g(298)≈1.85, indicating the rate of hydrogen embrittlement. It can be seen that the relative risk is reduced to 1/1.85≒0.54 times. 298K and 308K are examples of changes in the temperature T input to the second function g(T). Thus, multiple temperatures T are input to the second function g(T).
　相対的なリスクとは、引張応力Ｓ一定で温度Ｔを変化させた場合、又は温度Ｔ一定で引張強度Ｓを変化させた場合のリスクを意味する。なお、引張応力Ｓと温度Ｔの両方が変化した場合の相対的なリスクを評価することも可能である。例えば、引張応力Ｓが600MPaから900Mpaに増加し、且つ温度Ｔが298Kから308Kに増加した場合の平均破断時間ｔａｖｅの増加比は、例えばS（900）/S（600）×ｇ（308）/ｇ（298）≒0.43となり、水素脆化の相対的なリスクは1/0.43≒2.33倍に増加することが分かる。 The relative risk means the risk when the tensile stress S is constant and the temperature T is changed, or when the temperature T is constant and the tensile strength S is changed. It is also possible to evaluate the relative risk when both the tensile stress S and the temperature T change. For example, when the tensile stress S increases from 600 MPa to 900 MPa and the temperature T increases from 298 K to 308 K, the increase ratio of the average breaking time tave is, for example, S (900) / S (600) × g (308) /g(298)≈0.43, and the relative risk of hydrogen embrittlement increases 1/0.43≈2.33 times.
　以上説明したように、本実施形態に係る水素脆化リスク評価装置１は、温度Ｔが一定の鋼材に負荷する引張応力を変数とし、該引張応力の変化に対する鋼材の水素脆化による平均破断時間を表す第１関数ｆ（Ｓ）を求める第１関数生成部１０と、温度Ｔを変数とし、第１関数ｆ（Ｓ）に乗じることで平均破断時間ｔａｖｅを表す第２関数ｇ（Ｔ）を求める第２関数生成部２０と、第１関数ｆ（Ｓ）に引張応力Ｓの変化を入力して平均破断時間ｔａｖｅの増加比で表される水素脆化リスクを算出し、第２関数ｇ（Ｔ）に温度の変化を入力して平均破断時間ｔａｖｅの増加比で表される水素脆化リスクを算出する水素脆化リスク算出部３０とを備える。これにより、水素脆化要因の値の変化によって鋼材の水素脆化リスクがどのように変化するかを評価することができる。 As described above, the hydrogen embrittlement risk evaluation apparatus 1 according to the present embodiment uses the tensile stress applied to the steel material at a constant temperature T as a variable, and the average fracture time due to hydrogen embrittlement of the steel material with respect to the change in the tensile stress A first function generation unit 10 that obtains a first function f (S) that represents the temperature T, and a second function g (T) that represents the average rupture time t ave by multiplying the first function f (S) with the temperature T as a variable and the change in the tensile stress S to the first function f(S) to calculate the hydrogen embrittlement risk represented by the increase ratio of the average rupture time tave , and the second function a hydrogen embrittlement risk calculator 30 for calculating the hydrogen embrittlement risk represented by the increase ratio of the average rupture time t ave by inputting the temperature change to g(T). As a result, it is possible to evaluate how the hydrogen embrittlement risk of the steel material changes due to changes in the values of the hydrogen embrittlement factors.
　〔水素脆化リスク評価方法〕
　図４は、水素脆化リスク評価装置１（図１）が実行する水素脆化リスク評価方法の処理手順を示すフローチャートである。図４を参照して水素脆化リスク評価方法について説明する。 [Method for evaluating hydrogen embrittlement risk]
FIG. 4 is a flow chart showing the processing procedure of the hydrogen embrittlement risk assessment method executed by the hydrogen embrittlement risk assessment device 1 (FIG. 1). A hydrogen embrittlement risk evaluation method will be described with reference to FIG.
　水素脆化リスク評価装置１は、動作を開始すると先ず第１関数生成部１０が、温度Ｔが一定の鋼材に負荷する引張応力Ｓを変数とし、該引張応力Ｓの変化に対する鋼材の水素脆化による平均破断時間ｔａｖｅを表す第１関数ｆ（Ｓ）を求める第１関数生成ステップＳ１を行う。 When the hydrogen embrittlement risk evaluation device 1 starts to operate, first, the first function generation unit 10 sets the tensile stress S applied to the steel material at a constant temperature T as a variable, and determines the hydrogen embrittlement of the steel material with respect to the change in the tensile stress S. A first function generation step S1 is performed to obtain a first function f(S) representing the average rupture time t ave by .
　次に第２関数生成部２０は、温度Ｔを変数とし、第１関数ｆ（Ｓ）に乗じることで平均破断時間ｔａｖｅを表す第２関数ｇ（Ｔ）を求める第２関数生成ステップＳ２を行う。 Next, the second function generation unit 20 performs a second function generation step S2 to obtain a second function g(T) representing the average rupture time t ave by multiplying the first function f(S) with the temperature T as a variable. conduct.
　次に水素脆化リスク算出部３０は、第１関数ｆ（Ｓ）に引張応力Ｓの変化を入力して平均破断時間ｔａｖｅの増加比で表される水素脆化リスクを算出し、第２関数ｇ（Ｔ）に温度Ｔの変化を入力して平均破断時間ｔａｖｅの増加比で表される水素脆化リスクを算出する水素脆化リスク算出ステップＳ３とを行う。 Next, the hydrogen embrittlement risk calculation unit 30 inputs the change in the tensile stress S to the first function f(S) to calculate the hydrogen embrittlement risk represented by the increase ratio of the average rupture time t ave . A hydrogen embrittlement risk calculation step S3 is performed for calculating the hydrogen embrittlement risk represented by the increase ratio of the average rupture time tave by inputting the change in the temperature T into the function g(T).
　つまり、本実施形態に係る水素脆化リスク評価方法は、温度Ｔが一定の鋼材に負荷する引張応力Ｓを変数とし、該引張応力Ｓの変化に対する鋼材の水素脆化による平均破断時間ｔａｖｅを表す第１関数ｆ（Ｓ）を求める第１関数生成ステップＳ１と、温度Ｔを変数とし、第１関数ｆ（Ｓ）に乗じることで平均破断時間ｔａｖｅを表す第２関数ｇ（Ｔ）を求める第２関数生成ステップＳ２と、第１関数ｆ（Ｓ）に引張応力Ｓの変化を入力して平均破断時間ｔａｖｅの増加比で表される水素脆化リスクを算出し、第２関数ｇ（Ｔ）に温度Ｔの変化を入力して平均破断時間ｔａｖｅの増加比で表される水素脆化リスクを算出する水素脆化リスク算出ステップＳ３とを行う。これにより、引張応力Ｓと温度Ｔの値により、水素脆化の相対的なリスクがどのように変化するかを評価することが可能となる。 That is, in the method for evaluating the risk of hydrogen embrittlement according to the present embodiment, the tensile stress S applied to a steel material at a constant temperature T is used as a variable, and the average fracture time tave due to hydrogen embrittlement of the steel material with respect to changes in the tensile stress S is A first function generating step S1 for obtaining a first function f(S) representing the The second function generation step S2 to be obtained and the change in the tensile stress S are input to the first function f(S) to calculate the hydrogen embrittlement risk represented by the increase ratio of the average rupture time tave , and the second function g A hydrogen embrittlement risk calculation step S3 is performed for calculating the hydrogen embrittlement risk represented by the increase ratio of the average rupture time tave by inputting the change in the temperature T into (T). This makes it possible to evaluate how the relative risk of hydrogen embrittlement changes depending on the values of tensile stress S and temperature T.
　また、設備の水素脆化リスクの把握が可能となり、設備点検に優先順位を付けたり、リスクに応じた設備の更改を可能にする等、安全性と経済性を両立した設備の保守運用を実現することができる。 In addition, it is possible to grasp the hydrogen embrittlement risk of equipment, prioritize equipment inspections, and make it possible to upgrade equipment according to the risk, etc., realizing equipment maintenance operation that balances safety and economic efficiency. can do.
　水素脆化リスク評価装置１は、図５に示す汎用的なコンピュータシステムで実現することができる、例えば、ＣＰＵ５０、メモリ５１、ストレージ５２、通信部５３、入力部５４、及び出力部５５とを備える汎用的なコンピュータシテムにおいて、ＣＰＵ５０がメモリ５１上にロードされた所定のプログラムを実行することにより、水素脆化リスク評価装置１の各機能が実現される。所定のプログラムは、HDD、SSD、USBメモリ、CD-ROM、DVD-ROM、MOなどのコンピュータ読取り可能な記録媒体に記録することも、ネットワークを介して配信することもできる。 The hydrogen embrittlement risk assessment apparatus 1 can be realized by the general-purpose computer system shown in FIG. Each function of the hydrogen embrittlement risk assessment apparatus 1 is realized by the CPU 50 executing a predetermined program loaded on the memory 51 in a general-purpose computer system. The prescribed program can be recorded on computer-readable recording media such as HDD, SSD, USB memory, CD-ROM, DVD-ROM, MO, etc., or can be distributed via a network.
　本発明は、上記の実施形態に限定されるものではなく、その要旨の範囲内で変形が可能である。例えば、第１関数ｆ（Ｓ）は最小二乗法で回帰する例を示したが、他の数値演算を用いて回帰しても構わない。 The present invention is not limited to the above embodiments, and can be modified within the scope of the gist. For example, although the first function f(S) regresses by the method of least squares, it may be regressed using other numerical calculations.
　このように、本発明はここでは記載していない様々な実施形態等を含むことは勿論である。したがって、本発明の技術的範囲は上記の説明から妥当な特許請求の範囲に係る発明特定事項によってのみ定められるものである。 In this way, the present invention naturally includes various embodiments and the like that are not described here. Therefore, the technical scope of the present invention is defined only by the matters specifying the invention according to the valid scope of claims based on the above description.
１：水素脆化リスク評価装置
１０：第１関数生成部
２０：第２関数生成部
３０：水素脆化リスク算出部 1: Hydrogen embrittlement risk evaluation device 10: First function generator 20: Second function generator 30: Hydrogen embrittlement risk calculator

Claims (3)

  1. 　温度が一定の鋼材に負荷する引張応力を変数とし、該引張応力の変化に対する前記鋼材の水素脆化による平均破断時間を表す第１関数を求める第１関数生成ステップと、
    　温度を変数とし、前記第１関数に乗じることで前記平均破断時間を表す第２関数を求める第２関数生成ステップと、
    　前記第１関数に前記引張応力の変化を入力して前記平均破断時間の増加比で表される水素脆化リスクを算出し、前記第２関数に温度の変化を入力して前記平均破断時間の増加比で表される水素脆化リスクを算出する水素脆化リスク算出ステップと
    　を行う水素脆化リスク評価方法。     a first function generation step of obtaining a first function representing an average fracture time due to hydrogen embrittlement of the steel material with respect to changes in the tensile stress, using the tensile stress applied to the steel material at a constant temperature as a variable;
    a second function generating step of obtaining a second function representing the average rupture time by multiplying the first function with temperature as a variable;
    The change in the tensile stress is input to the first function to calculate the hydrogen embrittlement risk represented by the increase ratio of the average rupture time, and the change in temperature is input to the second function to increase the average rupture time. A hydrogen embrittlement risk evaluation method that performs a hydrogen embrittlement risk calculation step of calculating a hydrogen embrittlement risk represented by an increase ratio.
  2. 　前記平均破断時間をｔａｖｅ、前記第１関数をｆ（Ｓ）、前記第２関数をｇ（Ｔ）とした場合に、ここでＳは前記引張応力、Ｔは温度であり、前記平均破断時間は次式で表される
    Figure JPOXMLDOC01-appb-M000001
     　請求項１に記載の水素脆化リスク評価方法。     When the average time to rupture is tave , the first function is f(S), and the second function is g(T), where S is the tensile stress, T is the temperature, and the average time to rupture is is represented by
    Figure JPOXMLDOC01-appb-M000001
     The hydrogen embrittlement risk evaluation method according to claim 1.
  3. 　温度が一定の鋼材に負荷する引張応力を変数とし、該引張応力の変化に対する前記鋼材の水素脆化による平均破断時間を表す第１関数を求める第１関数生成部と、
    　温度を変数とし、前記第１関数に乗じることで前記平均破断時間を表す第２関数を求める第２関数生成部と、
    　前記第１関数に前記引張応力の変化を入力して前記平均破断時間の増加比で表される水素脆化リスクを算出し、前記第２関数に温度の変化を入力して前記平均破断時間の増加比で表される水素脆化リスクを算出する水素脆化リスク算出部と
    　を備える水素脆化リスク評価装置。     a first function generation unit that uses the tensile stress applied to a steel material at a constant temperature as a variable and obtains a first function representing the average fracture time due to hydrogen embrittlement of the steel material with respect to changes in the tensile stress;
    a second function generator that obtains a second function representing the average rupture time by multiplying the first function with the temperature as a variable;
    The change in the tensile stress is input to the first function to calculate the hydrogen embrittlement risk represented by the increase ratio of the average rupture time, and the change in temperature is input to the second function to increase the average rupture time. A hydrogen embrittlement risk evaluation device comprising: a hydrogen embrittlement risk calculation unit that calculates a hydrogen embrittlement risk represented by an increase ratio.
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KAMISHO TAKUYA, KAMISHO TAKUYA, ISHII RYUTA, TAKEUCHI YOSUKE, WATANABE MASAMITSU, TSUDA MASAYUKI: "Estimating the progress behavior of hydrogen embrittlement by statistical analysis of fracture time", ZAIRYO TO KANKYO - CORROSION ENGINEERING., FUSHIKU BOSHOKU KYOKAI, TOKYO., JP, vol. 68, no. 4, 10 April 2019 (2019-04-10), JP , pages 88 - 91, XP055938371, ISSN: 0917-0480, DOI: 10.3323/jcorr.68.88 *

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