JP2002022649A - Method for measuring surface crack length of high- temperature equipment - Google Patents
Method for measuring surface crack length of high- temperature equipmentInfo
- Publication number
- JP2002022649A JP2002022649A JP2000211254A JP2000211254A JP2002022649A JP 2002022649 A JP2002022649 A JP 2002022649A JP 2000211254 A JP2000211254 A JP 2000211254A JP 2000211254 A JP2000211254 A JP 2000211254A JP 2002022649 A JP2002022649 A JP 2002022649A
- Authority
- JP
- Japan
- Prior art keywords
- oxide film
- crack length
- crack
- length
- thickness
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は高温機器の表面き裂
長さ測定方法に関し、さらに詳しくはボイラを初めとす
る高温で使用される機器材料の表面き裂長さ測定方法に
関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the length of a surface crack of a high-temperature device, and more particularly to a method of measuring the surface crack length of a device material used at a high temperature such as a boiler.
【０００２】[0002]
【従来の技術】火力発電プラントや化学プラント等の高
温、高圧下で長時間使用される機器では、運転中に使用
材料がクリープ、疲労または時効損傷を受け、材質が劣
化することがよく知られている。このような材質劣化
は、使用材料のメタル温度、作用応力および使用時間に
よって支配されるものであり、火力発電用ボイラではこ
れらの支配因子を考慮し、通常１０万時間の寿命を持つ
ように設計されている。しかし、近年、設計寿命を超え
て運転されているボイラが多くなってきており、またボ
イラの運用条件において毎日の起動停止や負荷変化が増
加するのに伴い、応力集中部での熱疲労による損傷事例
や事故が多くなってきている。このような背景から材料
の余寿命、特に起動停止に伴う低サイクル疲労寿命を的
確に予測し、部分的な取換えや補修を計画的に行うこと
によって、プラントとしての寿命を延長するための技術
が重要となってきている。2. Description of the Related Art It is well known that materials used for a long time under high temperature and high pressure, such as thermal power plants and chemical plants, are deteriorated due to creep, fatigue or aging damage during operation. ing. Such material deterioration is governed by the metal temperature, working stress, and operating time of the material used. A boiler for thermal power generation is designed to have a lifetime of 100,000 hours in consideration of these governing factors. Have been. However, in recent years, the number of boilers that have been operating beyond their design life has increased, and the daily start / stop and load changes have increased under the operating conditions of the boiler. Cases and accidents are increasing. Against this background, technology to extend the life of a plant by accurately predicting the remaining life of the material, especially the low cycle fatigue life associated with starting and stopping, and systematically performing partial replacement and repair. Is becoming important.
【０００３】高温部材の低サイクル疲労寿命を非破壊的
に評価する方法としては、損傷の初期から材料表面に発
生する微小き裂をレプリカによって検出する方法が広く
用いられている。一般的には評価部位の表面酸化膜をグ
ラインダー等で除去し、研磨した後にレプリカを採取す
る。疲労き裂は表面に発生するため、表面酸化膜の除去
および研磨には細心の注意が必要であり、注意を怠る
と、き裂を除去したり、実際のき裂長さよりも測定値が
短くなったりする。このため、特開平６−５０９４２号
公報では、酸化皮膜を除去せず、磁界をかけた状態で酸
化皮膜の上から磁粉を塗り、粘着テープに磁粉を抽出し
て顕微鏡で観察する方法を提案している。この方法で
は、酸化皮膜のき裂長さと金属表面上の実際のき裂長さ
は同等としている。[0003] As a method for non-destructively evaluating the low cycle fatigue life of a high temperature member, a method of detecting a minute crack generated on a material surface from the beginning of damage by a replica is widely used. In general, a replica is collected after the surface oxide film at the evaluation site is removed with a grinder or the like and polished. Since fatigue cracks occur on the surface, extreme care must be taken when removing and polishing the surface oxide film.If care is not taken, cracks may be removed or the measured value may be shorter than the actual crack length. Or For this reason, Japanese Patent Application Laid-Open No. 6-50942 proposes a method in which a magnetic powder is applied from above the oxide film in a state in which a magnetic field is applied without removing the oxide film, and the magnetic powder is extracted on an adhesive tape and observed with a microscope. ing. In this method, the crack length of the oxide film is equal to the actual crack length on the metal surface.
【０００４】[0004]
【発明が解決しようとする課題】しかし、この関係が成
立するのは、低温で短時間（５００℃×１００時間）の
熱処理を行った室温疲労試験による損傷材の場合で、酸
化皮膜の厚さが０．０１mm以下の場合である。実用化さ
れる機器ではこれより高温で長時間使用されるため、酸
化皮膜厚さは厚くなる。例えば、使用温度を５７０℃と
し、１００，０００時間使用したとすれば、酸化皮膜の
厚さは約０．５mmとなり、上記の酸化皮膜厚さの１００
倍程度になる。このような場合、酸化皮膜上のき裂長さ
が、金属表面上の実際のき裂長さと異なる可能性が高
く、酸化皮膜上にき裂が観察された場合でも、金属表面
上にはき裂が検出できない場合もある。本発明の課題
は、上述した従来技術の問題点を解決し、酸化皮膜の厚
さが厚い場合でも、該酸化皮膜を除去することなく、高
温機器に使用される材料の表面き裂長さを正確に測定す
ることができる高温機器の表面き裂長さ測定方法を提供
することにある。However, this relationship holds only in the case of a damaged material obtained by a room temperature fatigue test in which heat treatment is performed at a low temperature for a short time (500 ° C. × 100 hours). Is 0.01 mm or less. Since a device to be put to practical use is used for a long time at a higher temperature, the thickness of the oxide film becomes thicker. For example, if the operating temperature is 570 ° C. and the device is used for 100,000 hours, the thickness of the oxide film is about 0.5 mm, and the thickness of the oxide film is 100 mm.
About double. In such a case, it is highly likely that the crack length on the oxide film is different from the actual crack length on the metal surface. Sometimes it cannot be detected. The object of the present invention is to solve the above-mentioned problems of the prior art, and to accurately determine the surface crack length of a material used for high-temperature equipment without removing the oxide film even when the thickness of the oxide film is large. It is an object of the present invention to provide a method for measuring the surface crack length of a high-temperature device which can be measured at a high speed.
【０００５】[0005]
【課題を解決するための手段】本願で特許請求される発
明は以下のとおりである。 （１）ボイラ等の高温機器で使用される材料に生成する
表面き裂長さを測定する方法において、 (i)該材料の調
査対象位置の酸化皮膜のき裂長さを測定する工程、(ii)
該酸化皮膜の厚さを測定する工程または使用温度と時間
から該酸化皮膜の厚さを推定する工程、および (iii)あ
らかじめ求めておいた酸化皮膜厚さごとの酸化皮膜のき
裂長さと金属表面のき裂長さの関係から、上記で測定し
た酸化皮膜のき裂長さを金属表面上のき裂長さに換算す
る工程を含むことを特徴とする高温機器の表面き裂長さ
測定方法。The invention claimed in the present application is as follows. (1) A method for measuring the length of a surface crack generated in a material used in a high-temperature device such as a boiler; (i) a step of measuring a crack length of an oxide film at a position to be inspected of the material; (ii)
A step of measuring the thickness of the oxide film or a step of estimating the thickness of the oxide film from use temperature and time; and (iii) a crack length and a metal surface of the oxide film for each oxide film thickness determined in advance. A method of converting the crack length of the oxide film measured above into a crack length on a metal surface from the relationship of the crack length of the high-temperature equipment.
【０００６】[0006]
【作用】酸化皮膜のき裂長さと金属表面のき裂長さの関
係を種々調査、試験した結果、以下のことが明らかにな
った。 １）金属表面上のき裂の発生に先立ち、酸化皮膜にき裂
が発生する。 ２）酸化皮膜厚さが薄い場合は酸化皮膜上のき裂長さと
金属表面上のき裂長さは同等である。 ３）酸化皮膜厚さが厚い場合で、酸化皮膜上のき裂長さ
が短い場合は、酸化皮膜にき裂が発生していても金属表
面上にはき裂が発生していない。 ４）酸化皮膜厚さが厚い場合で、酸化皮膜上のき裂長さ
が長い場合は、金属表面上のき裂長さは酸化皮膜のき裂
長さに近づく。[Action] Various investigations and tests on the relationship between the crack length of the oxide film and the crack length on the metal surface have revealed the following. 1) Prior to the occurrence of cracks on the metal surface, cracks occur in the oxide film. 2) When the thickness of the oxide film is small, the crack length on the oxide film is equal to the crack length on the metal surface. 3) When the thickness of the oxide film is large and the crack length on the oxide film is short, no crack is generated on the metal surface even if the oxide film is cracked. 4) When the thickness of the oxide film is large and the crack length on the oxide film is long, the crack length on the metal surface approaches the crack length of the oxide film.
【０００７】図１にこれらの結果を図示した。この酸化
皮膜厚さごとの酸化皮膜のき裂長さと金属表面のき裂長
さとの関係を示した図１を利用すれば、酸化皮膜のき裂
長さから金属表面上のき裂長さを求めることができる。
具体的には、酸化皮膜のき裂長さから金属表面のき裂長
さを求めるためには、酸化皮膜上のき裂長さを測定する
とともに酸化皮膜の厚さを求め、図１を利用して金属表
面上のき裂長さに換算することができる。FIG. 1 illustrates these results. Using FIG. 1 showing the relationship between the crack length of the oxide film and the crack length of the metal surface for each oxide film thickness, the crack length on the metal surface can be determined from the crack length of the oxide film. .
Specifically, in order to determine the crack length on the metal surface from the crack length of the oxide film, the crack length on the oxide film is measured and the thickness of the oxide film is determined. It can be converted to the crack length on the surface.
【０００８】本発明の方法では、従来技術と同じように
酸化皮膜を除去せずに酸化皮膜上のき裂長さを測定する
とともに、その部位の酸化皮膜厚さを測定するか、また
は温度と時間から酸化皮膜厚さを推定する。該酸化皮膜
厚さは超音波等で非破壊的に測定することができるが、
対象部位のメタル温度と使用時間から酸化皮膜厚さを推
定してもよい。次に、測定した酸化皮膜上のき裂長さを
図１に示す酸化皮膜厚さごとの酸化皮膜上のき裂長さと
金属表面上の実際のき裂長さとの関係に当てはめること
により、実際のき裂長さを推定する。In the method of the present invention, the crack length on the oxide film is measured without removing the oxide film as in the prior art, and the thickness of the oxide film at the site is measured or the temperature and time are measured. The thickness of the oxide film is estimated from the equation. The thickness of the oxide film can be measured nondestructively by ultrasonic waves or the like,
The oxide film thickness may be estimated from the metal temperature of the target part and the use time. Next, the actual crack length was determined by applying the measured crack length on the oxide film to the relationship between the crack length on the oxide film and the actual crack length on the metal surface for each oxide film thickness shown in FIG. Estimate.
【０００９】[0009]
【発明の実施の形態】以下、本発明を実施例により詳し
く説明する。図２に示す火力発電用ボイラの２次過熱器
出口管寄の表面き裂長さを本発明の方法を用いて測定し
た。測定対象部位は、２次過熱器出口管寄１のスタッブ
チューブ溶接止端部２とした。その材質は２．２５Ｃｒ
−１Ｍｏ鋼で、詳細な調査をするために缶端から１本
目、１２本目、２４本目（缶中央）の管を切出した。本
部位はメタル温度５５６℃で、累積運転時間約１１０，
０００時間、起動停止回数約２２００回で、高温である
ためクリープ損傷も進行するが、起動停止回数が多くな
ると天井壁と管寄との温度差に起因して低サイクル疲労
も発生し、缶端ほど疲労損傷は厳しくなる。DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments. The length of the surface crack near the outlet pipe of the secondary superheater of the boiler for thermal power generation shown in FIG. 2 was measured using the method of the present invention. The measurement target site was the stub tube weld toe 2 near the secondary superheater outlet tube 1. The material is 2.25Cr
The first, twelfth, and twenty-fourth (can center) tubes were cut from the end of the can with -1Mo steel for detailed investigation. This part has a metal temperature of 556 ° C and a cumulative operation time of about 110,
2,000 hours, start and stop times about 2200 times, creep damage progresses due to high temperature, but as the number of start and stop times increases, low cycle fatigue also occurs due to the temperature difference between the ceiling wall and the pipe, and the can end The more severe the fatigue damage is.
【００１０】これらのサンプルの溶接止端部の酸化皮膜
の上からき裂長さを測定し、図１を用いて金属表面上の
き裂長さを推定した。またこのサンプルの表面から酸化
皮膜を取り除き、金属表面上の実際のき裂長さを測定し
た。酸化皮膜厚さはメタル温度と運転時間から種々のデ
ータを整理して求めた次式を用いて算出した。 Ｙ2 ＝ｋp ・ｔ ｌｏｇ（ｋp ）＝１１．３９−９３２０（１／Ｔ） Ｙ：酸化皮膜厚さ（μｍ） ｔ：時間（ｈ） Ｔ：温度（Ｋ） ｋp ：速度定数（μｍ2 ／ｈ）[0010] The crack length was measured from above the oxide film on the weld toe of these samples, and the crack length on the metal surface was estimated using FIG. The oxide film was removed from the surface of this sample, and the actual crack length on the metal surface was measured. The oxide film thickness was calculated using the following equation, which was obtained by organizing various data from the metal temperature and the operation time. Y 2 = k p · t log (k p ) = 11.39-9320 (1 / T) Y: oxide film thickness (μm) t: time (h) T: temperature (K) k p : rate constant ( μm 2 / h)
【００１１】酸化皮膜上のき裂長さは、ＣＣＤカメラを
用いて直接観察し、き裂部分の画像をプリントアウトし
て長さを測定した。また酸化皮膜の厚さは上式から０．
３９mmと推定できたが、試験終了後、近傍の酸化皮膜厚
さを断面調査により測定したところ０．４０mmであり、
上式での推定がほぼ妥当であることが確認できた。これ
らの酸化皮膜上のき裂長さと酸化皮膜厚さから図１を用
いて金属表面上のき裂長さを推定した。次に細心の注意
を払って酸化皮膜を除去および研磨を行い、レプリカを
採取して光学顕微鏡でき裂長さを測定した。これらの測
定結果を表１に示したが、酸化皮膜上のき裂長さから推
定した金属表面上のき裂長さと、実際に測定した金属表
面上のき裂長さはほぼ同等であり、本発明の方法の妥当
性が確認された。なお、酸化皮膜上のき裂長さを測定す
る手段としては、特に前記のようなＣＣＤカメラを用い
たものに限定する必要はなく、き裂長さを正確に写し取
る手段であればいずれでもかまわない。The length of the crack on the oxide film was directly observed using a CCD camera, and an image of the crack was printed out to measure the length. In addition, the thickness of the oxide film is determined to be 0.1 from the above equation.
It was estimated to be 39 mm, but after the test was completed, the thickness of the oxide film in the vicinity was measured by a cross-sectional survey and found to be 0.40 mm.
It was confirmed that the estimation by the above equation was almost valid. The crack length on the metal surface was estimated from the crack length on the oxide film and the oxide film thickness using FIG. Next, the oxide film was removed and polished with great care, and replicas were collected, and the crack length was measured with an optical microscope. The results of these measurements are shown in Table 1. The crack length on the metal surface estimated from the crack length on the oxide film and the actually measured crack length on the metal surface were almost the same. The validity of the method was confirmed. The means for measuring the length of the crack on the oxide film is not particularly limited to the one using the CCD camera as described above, and any means for accurately copying the length of the crack may be used.
【００１２】[0012]
【表１】 [Table 1]
【００１３】[0013]
【発明の効果】本発明の高温機器の表面き裂長さ測定法
によれば、酸化皮膜の厚さが厚い場合でも、該酸化皮膜
を除去することなく、高温機器に使用される材料の表面
き裂長さを正確に測定することができ、高温機器の非破
壊的余寿命診断法の精度向上ならびに効率化に寄与する
ことができる。According to the method for measuring the surface crack length of high-temperature equipment of the present invention, even when the thickness of the oxide film is large, the surface crack of the material used for the high-temperature equipment can be obtained without removing the oxide film. The crack length can be measured accurately, which can contribute to the improvement of the accuracy and efficiency of the nondestructive remaining life diagnosis method for high-temperature equipment.
【図面の簡単な説明】[Brief description of the drawings]
【図１】酸化皮膜厚さをパラメータとした酸化皮膜上の
き裂長さと金属表面上のき裂長さの関係を示す図。FIG. 1 is a view showing a relationship between a crack length on an oxide film and a crack length on a metal surface with the oxide film thickness as a parameter.
【図２】実施例で測定対象としたボイラ２次過熱器出口
管寄の概略図。FIG. 2 is a schematic diagram of a boiler secondary superheater outlet pipe as a measurement target in the embodiment.
１…２次過熱器出口管寄、２…スタッブチューブ溶接止
端部。1 ... near the outlet of the secondary superheater, 2 ... stub tube weld toe.
Claims (1)
生成する表面き裂長さを測定する方法において、 (i)該
材料の調査対象位置の酸化皮膜のき裂長さを測定する工
程、(ii)該酸化皮膜の厚さを測定する工程または使用温
度と時間から該酸化皮膜の厚さを推定する工程、および
(iii)あらかじめ求めておいた酸化皮膜厚さごとの酸化
皮膜のき裂長さと金属表面のき裂長さの関係から、上記
で測定した酸化皮膜のき裂長さを金属表面上のき裂長さ
に換算する工程を含むことを特徴とする高温機器の表面
き裂長さ測定方法。1. A method for measuring the length of a surface crack generated in a material used in a high-temperature device such as a boiler, comprising: (i) a step of measuring a crack length of an oxide film at a position to be investigated of the material; ii) measuring the thickness of the oxide film or estimating the thickness of the oxide film from use temperature and time; and
(iii) From the previously determined relationship between the crack length of the oxide film and the crack length of the metal surface for each oxide film thickness, convert the crack length of the oxide film measured above to the crack length on the metal surface. A method for measuring the length of a surface crack of a high-temperature device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000211254A JP2002022649A (en) | 2000-07-12 | 2000-07-12 | Method for measuring surface crack length of high- temperature equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000211254A JP2002022649A (en) | 2000-07-12 | 2000-07-12 | Method for measuring surface crack length of high- temperature equipment |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2002022649A true JP2002022649A (en) | 2002-01-23 |
Family
ID=18707389
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000211254A Pending JP2002022649A (en) | 2000-07-12 | 2000-07-12 | Method for measuring surface crack length of high- temperature equipment |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2002022649A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005134115A (en) * | 2003-10-28 | 2005-05-26 | Babcock Hitachi Kk | Diagnostic method and risk evaluation method for tendency of low-cycle fatigue damage of equipement |
-
2000
- 2000-07-12 JP JP2000211254A patent/JP2002022649A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005134115A (en) * | 2003-10-28 | 2005-05-26 | Babcock Hitachi Kk | Diagnostic method and risk evaluation method for tendency of low-cycle fatigue damage of equipement |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4924708A (en) | Method for calculating crack lengths of conductive sensors | |
| JP3652943B2 (en) | Metal material damage evaluation method and apparatus | |
| KR101786028B1 (en) | Method and system of deterministic fatigue life prediction for rotor materials | |
| JP2007263603A (en) | System for assessing remaining life of high-temperature plant equipment and remaining life assessment method using same | |
| JPH0621783B2 (en) | Fatigue / remaining life evaluation method for machine parts | |
| JP2008014959A (en) | Method for inspecting coating member for interface defects | |
| JP3064107B2 (en) | High-temperature damage evaluation method for austenitic heat-resistant steel | |
| JP3976938B2 (en) | Creep life evaluation method | |
| JP2001174380A (en) | Method and apparatus for predicting remaining life of structural material | |
| JPH09195795A (en) | Remaining life evaluation method for gas turbine stationary blade and device thereof | |
| JP2002022649A (en) | Method for measuring surface crack length of high- temperature equipment | |
| CN110082493A (en) | A kind of creep life scene quick nondestructive appraisal procedure of high temperature steam guiding tube | |
| JPH075086A (en) | Method for estimating superposed damage of creep and fatigue of high-temperature structure material | |
| JP2007225333A (en) | Damage evaluation method by metal texture as to creep fatigue damage | |
| JP3015599B2 (en) | Creep damage evaluation method for ferritic heat-resistant steel | |
| JP3064110B2 (en) | High-temperature damage evaluation method for austenitic heat-resistant steel | |
| JPH1183842A (en) | Remaining service life determination method for cr-mo steel heating furnace pipe | |
| JPH11237912A (en) | Method and device for maintenance and management of high-temperature structural member | |
| JPH0313861A (en) | Method for detecting damage in metal | |
| JP2540630B2 (en) | Method of evaluating remaining life of ferritic heat resistant steel | |
| JPH08160035A (en) | Method and apparatus for controlling life of high temperature part of gas turbine | |
| JP2020118566A (en) | High-temperature apparatus remaining life evaluation method and remaining life evaluation assisting system | |
| JP3331459B2 (en) | Ceramic coating remaining life evaluation diagnostic system | |
| JP3009698B2 (en) | Remaining life diagnosis method and remaining life diagnosis system | |
| JPS5860248A (en) | Life forecast for high temperature apparatus |