JPH0634625A - High temperature damage evaluation of austenitic heat resistant steel - Google Patents

High temperature damage evaluation of austenitic heat resistant steel

Info

Publication number
JPH0634625A
JPH0634625A JP4189449A JP18944992A JPH0634625A JP H0634625 A JPH0634625 A JP H0634625A JP 4189449 A JP4189449 A JP 4189449A JP 18944992 A JP18944992 A JP 18944992A JP H0634625 A JPH0634625 A JP H0634625A
Authority
JP
Japan
Prior art keywords
grain boundary
damage
austenitic heat
resistant steel
high temperature
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.)
Granted
Application number
JP4189449A
Other languages
Japanese (ja)
Other versions
JP3064107B2 (en
Inventor
Nobuhiko Nishimura
宣彦 西村
Fujimitsu Masuyama
不二光 増山
Toshiyuki Imazato
敏幸 今里
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mitsubishi Heavy Industries Ltd
Original Assignee
Mitsubishi Heavy Industries Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Mitsubishi Heavy Industries Ltd filed Critical Mitsubishi Heavy Industries Ltd
Priority to JP4189449A priority Critical patent/JP3064107B2/en
Publication of JPH0634625A publication Critical patent/JPH0634625A/en
Application granted granted Critical
Publication of JP3064107B2 publication Critical patent/JP3064107B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Abstract

PURPOSE:To evaluate a degree of damage of austenitic heat resistant steel in a shorter time than a breaking test with the same precision as it. CONSTITUTION:In a high temperature damage evaluation method of austenitic heat resistant steel, surfaces of mechanical component are polished, etched, metal metal structure is observed with a replica method or a direct observation method. Minute cavities produced in a grain boundary of certain area of the observed metal structure and length in the direction of the grain boundary of grain boundary deposit are measured. Said individual measurement values are added, a total value of the minute cavities produced in the certain area and the length of the grain boundary deposit is divided by the certain area or another total value of the length of the grain boundary in the certain area, and a grain boundary damage linear density and a grain boundary damage rate are found. Said measurement values are fit in a relative chart of the grain boundary damage linear density previously found in a laboratory or the grain boundary damage rate and a lifetime consumption rate for the purpose of obtaining the lifetime consumption rate of heat resistant steel.

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【産業上の利用分野】この発明はオーステナイト系耐熱
鋼の高温損傷評価方法に関し、特にオ−ステナイト系耐
熱鋼が使用される火力発電プラント等の高温機器の供用
中の検査技術に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for evaluating high temperature damage of austenitic heat resistant steel, and more particularly to an in-service inspection technique for high temperature equipment such as a thermal power plant using austenitic heat resistant steel.

【0002】[0002]

【従来の技術】従来から、高温、応力下で使用されてい
るオ−ステナイト系耐熱鋼のクリ−プ、クリ−プ疲労等
の高温損傷を評価する方法としては、使用されている材
料を切り出してクリ−プ破断試験、クリ−プ疲労試験等
の破壊試験を行って、未使用状態からの強度低下度を評
価する方法(以後、破壊試験法と称す)、使用された温
度、応力、時間から未使用材の強度を用いて損傷度を推
定する方法(以後、応力解析法と称す)が多用されてい
た。
2. Description of the Related Art Conventionally, as a method for evaluating high temperature damage such as creep and creep fatigue of austenitic heat-resistant steel which has been used under high temperature and stress, the material used is cut out. Method to evaluate the degree of strength decrease from the unused state by performing a fracture test such as creep rupture test, creep fatigue test (hereinafter referred to as a fracture test method), temperature, stress, time used Therefore, a method of estimating the degree of damage using the strength of an unused material (hereinafter referred to as a stress analysis method) has been widely used.

【0003】また、非破壊的な手法としては、レプリカ
法等によって該機械部品の表面の金属組織を観察し、ク
リ−プ損傷の蓄積と共に生成するクリ−プボイドの数や
面積を計測する方法が用いられている。
As a non-destructive method, there is a method of observing the metallographic structure of the surface of the mechanical part by a replica method or the like and measuring the number and area of creep voids generated together with the accumulation of creep damage. It is used.

【0004】[0004]

【発明が解決しようとする課題】上述した破壊試験法で
は、機械部品として使用されたオ−ステナイト系耐熱鋼
を破壊試験に供するために切断する必要があることか
ら、その後の該機械の運転のためには、切断工事に加え
て切断した部品を修理するのに費用、工期がかかってい
た。また、長時間機械部品として使用された該オ−ステ
ナイト系耐熱鋼の損傷を評価するためには、なるべく該
機械の運転条件に近い状態で試験を実施する必要があ
り、評価に時間を要していた。
In the above-mentioned fracture test method, since it is necessary to cut the austenitic heat-resistant steel used as a machine part for use in the fracture test, the subsequent operation of the machine is Therefore, in addition to the cutting work, it took a lot of time and money to repair the cut parts. Further, in order to evaluate the damage of the austenitic heat-resisting steel used as a machine part for a long time, it is necessary to carry out a test in a state as close as possible to the operating conditions of the machine, and the evaluation requires time. Was there.

【0005】一方、強度評価法では、機械部品を切断す
る必要はないが、評価に必要な該オ−ステナイト系耐熱
鋼の強度デ−タとして、実際に使用された材料ではな
く、同じ種類の材料のデ−タを用いる必要があることか
ら、実際使用された材料強度デ−タと応力解析の評価に
用いた材料強度デ−タとの差に起因した誤差をもってい
た。
On the other hand, in the strength evaluation method, it is not necessary to cut the mechanical parts, but as the strength data of the austenitic heat-resisting steel necessary for the evaluation, it is not the material actually used but the same kind of material. Since it was necessary to use the material data, there was an error due to the difference between the material strength data actually used and the material strength data used for the stress analysis evaluation.

【0006】さらに、クリ−プボイドを計測する方法
は、上述した破壊検査法のように該機械部品を切断する
必要がなく、また長期にわたる試験を実施する必要もな
い。また、強度評価法のように未知の材料強度デ−タも
必要としない。しかし、一般にクリ−プ損傷の過程でオ
−ステナイト鋼にクリ−プボイドが生成するのは破壊ま
での寿命の後半であり、この手法では寿命前半の損傷評
価を行うことはできなかった。
Furthermore, the method for measuring creep voids does not require cutting of the mechanical parts as in the above-described destructive inspection method, nor does it require long-term tests. Further, unlike the strength evaluation method, unknown material strength data is not required. However, in general, the formation of creep voids in austenitic steel in the course of creep damage occurs in the latter half of the life until fracture, and this method cannot evaluate the damage in the first half of the life.

【0007】この発明はこうした事情を考慮してなされ
たもので、高温で運転される機械部品に使用されている
オーステナイト系耐熱鋼の損傷の程度を、破壊試験法よ
りも短時間でかつ同等の精度で行ないうるオーステナイ
ト系耐熱鋼の高温損傷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 the above circumstances, and the degree of damage of austenitic heat-resistant steel used for machine parts operated at high temperatures can be determined in a shorter period of time than in the destructive test method and at the same level. An object of the present invention is to provide a high temperature damage evaluation method for austenitic heat resistant steel which can be performed with high accuracy.

【0008】[0008]

【課題を解決するための手段】従来技術の持つ上記不具
合点を改善するために、本発明は以下の特徴を持つ。 (1)機械部品として実際に使用されているオ−ステナ
イト系耐熱鋼を切断することなく、その表面を研磨、エ
ッチングして、レプリカ法等によって該表面に現出した
金属組織を観察するだけで損傷の程度を評価する。 (2)実際に使用された該オ−ステナイト系耐熱鋼にお
いて、高温損傷と直接関係する粒界析出物およびボイド
を定量化して損傷評価する。
The present invention has the following features in order to improve the above problems of the prior art. (1) Without cutting the austenitic heat-resisting steel actually used as a mechanical part, the surface of the austenitic heat-resistant steel is polished and etched, and the metal structure exposed on the surface is observed by a replica method or the like. Assess the degree of damage. (2) In the actually used austenitic heat resistant steel, grain boundary precipitates and voids directly related to high temperature damage are quantified and damage is evaluated.

【0009】(3)粒界析出物およびボイドの定量化方
法として、一定面積中の粒界析出物およびボイドの結晶
粒界方向の長さ、または、一定面積中の全粒界の長さに
対する粒界析出物およびボイドの結晶粒界方向の長さの
比を用いる。
(3) As a method for quantifying grain boundary precipitates and voids, the lengths of grain boundary precipitates and voids in a certain area in the grain boundary direction or the lengths of all grain boundaries in a certain area are measured. The ratio of the lengths of grain boundary precipitates and voids in the grain boundary direction is used.

【0010】即ち、この発明は、高温、応力下で運転さ
れる機械部品として使用されているオ−ステナイト系耐
熱鋼の高温損傷を評価する方法において、前記機械部品
の表面を研磨、エッチングして前記オ−ステナイト系耐
熱鋼の金属組織を現出させる工程と、現出させた金属組
織をレプリカ法又は直接観察法によって観察する工程
と、観察された金属組織の一定面積中の結晶粒界に生成
した微小空洞と粒界析出物の結晶粒界方向の長さを計測
する工程と、個々の該測定値を加算して該一定面積中に
生成した微小空洞及び粒界析出物の長さの合計値を該一
定面積又は該一定面積中の結晶粒界の長さの合計値で除
し、粒界損傷線密度(単位面積あたりの微小空洞)及び
粒界損傷率(単位面積あたりの粒界析出物長さ)を求め
る工程と、予め実験室試験によって求めた粒界損傷線密
度、又は粒界損傷率と寿命消費率との関係線図に該測定
値をあてはめることによって前記オ−ステナイト系の耐
熱鋼の寿命消費率を求める工程とを具備することを特徴
とするオーステナイト系耐熱鋼の高温損傷評価方法であ
る。
That is, the present invention relates to a method for evaluating high-temperature damage of austenitic heat-resistant steel used as a mechanical part that is operated under high temperature and stress, by polishing and etching the surface of the mechanical part. The step of exposing the metallographic structure of the austenitic heat-resistant steel, the step of observing the exposed metallographic structure by the replica method or the direct observation method, and at the grain boundaries in a certain area of the observed metallographic structure. A step of measuring the lengths of the generated minute cavities and the grain boundary precipitates in the crystal grain boundary direction, and the individual measured values are added to calculate the lengths of the minute cavities and the grain boundary precipitates generated in the certain area. The total value is divided by the total value of the fixed area or the length of the crystal grain boundary in the fixed area, and the grain boundary damage linear density (microcavities per unit area) and the grain boundary damage rate (grain boundary per unit area) Preliminary experiment with the process of obtaining the deposit length) Grain boundary damage linear density obtained by the test, or a step of determining the life consumption rate of the austenitic heat-resistant steel by applying the measured value to the relationship diagram between the grain boundary damage rate and the life consumption rate. A high temperature damage evaluation method for austenitic heat resistant steels.

【0011】[0011]

【作用】上述したこの発明の特徴の作用は、以下のとお
りである。 (1)金属組織を観察するだけで損傷を評価するため、
調査ならびに調査後の機械部品の復旧が容易であるとと
もに、評価に要する時間、費用が少ない。
The operation of the features of the present invention described above is as follows. (1) Since damage is evaluated simply by observing the metal structure,
It is easy to conduct an investigation and restore mechanical parts after the investigation, and the time and cost required for evaluation are small.

【0012】(2)調査対象部品の金属組織を直接観察
することによって損傷を評価することから、応力解析法
のように材料特性のばらつきによる評価精度の誤差が生
じない。
(2) Since the damage is evaluated by directly observing the metallographic structure of the component to be investigated, there is no error in the evaluation accuracy due to the variation of the material characteristics as in the stress analysis method.

【0013】(3)オ−ステナイト系耐熱鋼の高温環境
下での使用による破壊までの寿命の前半および後半の高
温損傷の主な要因である、それぞれ粒界析出物およびボ
イド、を定量化することによって損傷評価することから
破壊までの寿命の初期から末期までの損傷の評価精度が
高く、また、粒界析出物およびボイドの生成状況の定量
化方法として、一定面積中の粒界方向の各々の長さを用
いたことから、面積等に比べてエッチング液、エッチン
グ時間等のエッチング条件による大きさの変化の影響を
受けにくい。
(3) Quantification of grain boundary precipitates and voids, which are the main factors of the high temperature damage in the first half and the second half of the life of the austenitic heat-resisting steel used in a high temperature environment before fracture, respectively. The accuracy of damage evaluation from the beginning to the end of the life from the damage evaluation to the fracture is high, and as a quantification method of grain boundary precipitates and voids, Since the length is used, it is less affected by the size change due to the etching conditions such as the etching solution and the etching time than the area.

【0014】[0014]

【実施例】以下、この発明における実施例を図面等を参
照して説明する。
Embodiments of the present invention will be described below with reference to the drawings.

【0015】本発明者等は、高温で使用される機械部品
として使用されたオ−ステナイト系耐熱鋼及び実験室的
にクリ−プ破断試験、クリ−プ疲労試験を破壊までの種
々の時間で中断させたオ−ステナイト系耐熱鋼の組織調
査を行った。
The inventors of the present invention conducted austenitic heat-resistant steel used as a machine part used at high temperatures and a laboratory creep rupture test and creep fatigue test at various times until fracture. The structure of the suspended austenitic heat resistant steel was investigated.

【0016】その結果、前記オ−ステナイト系耐熱鋼に
は高温損傷の蓄積に伴って、まず、その結晶粒界に粗大
な金属間化合物や炭化物が生成し、寿命の後半になると
粗大な金属間化合物や炭化物に隣接して微小な空洞(ボ
イド)が生成することを見いだした。また、ボイドは粒
界析出物に隣接して生成するが、研磨やエッチングによ
っては研磨、エッチング過程で析出物が脱落して生じた
微小な空洞とボイドとの判別が容易ではない場合があっ
た。
As a result, in the austenitic heat-resisting steel, coarse intermetallic compounds and carbides are first formed in the grain boundaries of the austenitic heat-resistant steel, and coarse intermetallic compounds are formed in the second half of the life. It was found that minute cavities (voids) were formed adjacent to the compounds and carbides. Further, although voids are formed adjacent to the grain boundary precipitates, it may not be easy to distinguish between the voids and the minute cavities caused by the falling of the precipitates during polishing or etching depending on polishing or etching. .

【0017】下記「表1」は、3種類のエッチング液を
用いて同じ試験片のエッチングを行って金属組織を現出
させたJIS 規格 SUS321HTB 鋼のクリ−プ中断試験片の
粒界析出物およびボイドの生成状況を、一定面積中の粒
界析出物およびボイドの数(粒界析出物数密度およびボ
イド数密度)、各々の面積(粒界析出物面積率およびボ
イド面積率)、各々の長さの合計(粒界析出物およびボ
イド線密度)によって定量化した結果を示す。
The following "Table 1" shows the grain boundary precipitates of the creep interruption test piece of JIS standard SUS321HTB steel in which the same test piece was etched using three kinds of etching solutions to reveal the metal structure. The generation state of voids is determined by the number of grain boundary precipitates and voids in a given area (grain boundary precipitate number density and void number density), each area (grain boundary precipitate area ratio and void area ratio), and each length. The results quantified by the sum of the thicknesses (grain boundary precipitates and void linear density) are shown.

【0018】[0018]

【表1】 [Table 1]

【0019】粒界析出物面積率およびボイド面積率は、
各々の数密度、線密度と比較して、エッチング液によっ
てその計測値が大きく変化していた。また、各々の数密
度および線密度と比べて各々の計測値をたし合わせた値
(以後、それぞれ、粒界損傷数密度および線密度と称
す)は、エッチング液によるばら付きがさらに小さくな
っていた。
The grain boundary precipitate area ratio and the void area ratio are
Compared to each number density and linear density, the measured values were greatly changed depending on the etching solution. Further, the values obtained by adding the respective measured values to the respective number densities and linear densities (hereinafter referred to as grain boundary damage number densities and linear densities, respectively) have smaller variations due to the etching solution. It was

【0020】そこで、試験温度700℃、試験応力6.
0kgf/mm2 におけるクリ−プ試験を種々の時間で中断さ
せた前記SUS321HTB 鋼のクリ−プ中断試験片の粒界析出
物およびボイドの数密度、線密度を測定した。図1に粒
界析出物およびボイドの数密度および線密度と寿命消費
率との関係を示す。なお、寿命消費率は試験温度700
℃、試験応力6.0kgf/mm2 における前記SUS321HTB 鋼
のクリ−プ破断時間に対する中断時間の割合とした。
Therefore, the test temperature is 700 ° C. and the test stress is 6.
0 kgf / mm 2 The number density and linear density of grain boundary precipitates and voids of the creep interruption test piece of the SUS321HTB steel obtained by interrupting the creep test at various times were measured. FIG. 1 shows the relationship between the number density and linear density of grain boundary precipitates and voids and the life consumption rate. The life consumption rate is 700 at the test temperature.
℃, test stress 6.0kgf / mm 2 The ratio of the interruption time to the creep rupture time of the SUS321HTB steel in the above.

【0021】ボイド数密度は、寿命中期に増加するもの
の、寿命中期以降はほとんど増加しなかった。一方、ボ
イド線密度は寿命の初期から末期まで連続的に増加して
おり、ボイド数密度よりもボイド線密度の方が寿命中期
以降の損傷評価に適していることが明らかになった。一
方、粒界析出物数密度および線密度は寿命の初期から中
期にかけて変化しており、この手法が寿命の初期から中
期にかけての損傷評価に適していることが明らかになっ
た。また、粒界損傷線密度は寿命の初期から末期まで連
続的に変化しており、この測定によりオ−ステナイト鋼
の高温損傷を寿命の初期から末期まで評価できる可能性
があることがわかった。そこで、発電用ボイラの伝熱管
として長時間高温、応力下で使用された2体のSUS321HT
B 鋼の損傷の程度を本発明方法よって評価した。
The void number density increased in the middle of the life, but hardly increased after the middle of the life. On the other hand, the void linear density increased continuously from the beginning to the end of the life, and it became clear that the void linear density is more suitable for damage evaluation after the middle of the life than the void number density. On the other hand, the grain boundary precipitate number density and linear density changed from the early to the middle of the life, and it became clear that this method is suitable for damage evaluation from the early to the middle of the life. Further, the grain boundary damage linear density continuously changes from the beginning to the end of the life, and it was found that the high temperature damage of the austenitic steel could be evaluated from the beginning to the end of the life by this measurement. Therefore, two SUS321HT used as a heat transfer tube for a power generation boiler under high temperature and stress for a long time.
The extent of damage to B steel was evaluated by the method of the present invention.

【0022】即ち、該伝熱管表面をグラインダ−、研磨
紙、ダイヤモンド粒子を用いて鏡面になるまで順次研磨
し、その後硝酸、フッ酸、エタノ−ルおよび水からなる
混合液でエッチングして金属組織を現出させた。さら
に、現出させた金属組織をレプリカ法によって転写し、
走査型電子顕微鏡によって採取したレプリカの組織調査
を行い、500倍の倍率で連続して30視野の走査型電
子顕微鏡写真を撮影した。 撮影した写真に観察された
個々の粒界析出物およびボイドの長さを計測し、観察し
た領域中に観察されたすべての粒界析出物およびボイド
の長さを合計し、これを観察面積で除した値を粒界損傷
線密度とした。得られた粒界損傷線密度を図1に示した
粒界損傷線密度と寿命消費率との関係線図にあてはめ、
寿命消費率を求めた。
That is, the surface of the heat transfer tube is sequentially polished with a grinder, polishing paper and diamond particles until it becomes a mirror surface, and then etched with a mixed solution of nitric acid, hydrofluoric acid, ethanol and water to obtain a metal structure. Was revealed. Furthermore, the exposed metal structure is transferred by the replica method,
The structure of the replica taken by the scanning electron microscope was examined, and scanning electron microscope photographs of 30 fields of view were taken continuously at a magnification of 500 times. The length of each grain boundary precipitate and void observed in the photograph taken was measured, and the lengths of all grain boundary precipitates and voids observed in the observed area were summed, and this was calculated as the observed area. The value obtained by dividing was the grain boundary damage linear density. The obtained grain boundary damage linear density was applied to the relationship diagram between the grain boundary damage linear density and the life consumption rate shown in FIG.
The life consumption rate was calculated.

【0023】また、上記調査の後、前記伝熱管を抜管
し、クリ−プ破断試験片を採取して、試験温度700
℃、応力6.0kgf/mm2 でクリ−プ破断試験を実施し
た。その結果得られた前記伝熱管のクリ−プ破断時間
と、同等鋼種の未使用材の同一条件下のクリ−プ破断試
験の結果得られた破断時間から、前記伝熱管のクリ−プ
破断寿命消費率を求めた結果を、下記「表2」に示す。
After the above investigation, the heat transfer tube was removed, and a creep rupture test piece was sampled at a test temperature of 700.
℃, stress 6.0kgf / mm 2 The creep rupture test was carried out. The creep rupture life of the heat transfer tube obtained from the creep rupture time of the heat transfer tube obtained as a result and the rupture time obtained as a result of the creep rupture test under the same conditions of an unused material of the same steel type. The results of calculating the consumption rate are shown in "Table 2" below.

【0024】[0024]

【表2】 両者の結果は精度よく一致しており、本発明方法による
評価結果は、破壊試験法による評価結果とほぼ同等であ
ることが明らかになった。上述したように、本発明方法
によれば、破壊試験法よりも短時間で簡便に、破壊試験
法とほぼ同等の精度の寿命評価法を提供できる。
[Table 2] The results of both were in good agreement, and it was revealed that the evaluation result by the method of the present invention is almost the same as the evaluation result by the destructive test method. As described above, according to the method of the present invention, it is possible to provide a life evaluation method with a precision almost equal to that of the destructive test method in a shorter time and more easily than the destructive test method.

【0025】また、同様の結果は、粒界析出物およびボ
イドの粒界方向の長さの和を計測面積ではなく、計測面
積中のすべての粒界の長さで除した値を用いても得られ
た。さらに、同様の結果は、SUS347鋼およびSUS316鋼に
おいても得られた。
Further, the same result can be obtained by using a value obtained by dividing the sum of the lengths of grain boundary precipitates and voids in the grain boundary direction by the length of all grain boundaries in the measured area, not by the measured area. Was obtained. Furthermore, similar results were obtained with SUS347 and SUS316 steels.

【0026】[0026]

【発明の効果】上述したように、この発明方法によれ
ば、高温で運転される機械部品に使用されているオ−ス
テナイト系耐熱鋼の損傷の程度を破壊試験法よりも短時
間で且つ同等の精度で行う損傷評価方法を提供できるこ
とから、機械部品の供用中検査の迅速化を図ることがで
きる。さらに、評価に機械部品の切断、復旧作業を伴わ
ないこと、および長時間に渡る機械試験を行わなくても
良いことから、破壊試験法よりも簡便で且つ安価であ
り、評価工事の効率化、検査範囲の拡大による検査精度
の向上が期待できる。
As described above, according to the method of the present invention, the degree of damage of the austenitic heat-resistant steel used for machine parts operated at high temperature can be made to be equal in a shorter time than the destructive test method. Since it is possible to provide a damage evaluation method with the accuracy of, it is possible to speed up the in-service inspection of mechanical parts. Furthermore, because the evaluation does not involve cutting of mechanical parts, restoration work, and it is not necessary to perform a mechanical test for a long time, it is simpler and cheaper than the destructive testing method, and the efficiency of evaluation work is improved. It is expected that the inspection accuracy will be improved by expanding the inspection range.

【図面の簡単な説明】[Brief description of drawings]

【図1】この発明の一実施例として得られた、JIS 規格
SUS321HTB 鋼のクリ−プ中断材の組織解析による粒界
析出物およびボイドの数密度および線密度とクリ−プ破
断寿命消費率との関係線図。
FIG. 1 is a JIS standard obtained as an embodiment of the present invention.
FIG. 3 is a diagram showing the relationship between the number densities and linear densities of grain boundary precipitates and voids and the creep rupture life consumption rate by the microstructure analysis of the creep interrupted material of SUS321HTB steel.

Claims (1)

【特許請求の範囲】[Claims] 【請求項1】 高温、応力下で運転される機械部品とし
て使用されているオ−ステナイト系耐熱鋼の高温損傷を
評価する方法において、前記機械部品の表面を研磨、エ
ッチングして前記オ−ステナイト系耐熱鋼の金属組織を
現出させる工程と、現出させた金属組織をレプリカ法又
は直接観察法によって観察する工程と、観察された金属
組織の一定面積中の結晶粒界に生成した微小空洞と粒界
析出物の結晶粒界方向の長さを計測する工程と、個々の
該測定値を加算して該一定面積中に生成した微小空洞及
び粒界析出物の長さの合計値を該一定面積又は該一定面
積中の結晶粒界の長さの合計値で除し、粒界損傷線密度
及び粒界損傷率を求める工程と、予め実験室試験によっ
て求めた粒界損傷線密度、又は粒界損傷率と寿命消費率
との関係線図に該測定値をあてはめることによって前記
オ−ステナイト系の耐熱鋼の寿命消費率を求める工程と
を具備することを特徴とするオーステナイト系耐熱鋼の
高温損傷評価方法。
1. A method for evaluating the high temperature damage of an austenitic heat resistant steel used as a machine part that is operated under high temperature and stress, wherein the surface of the machine part is polished and etched to obtain the austenite. Of revealing the metallographic structure of heat-resistant steels, observing the developed metallographic structure by the replica method or direct observation method, and microcavities formed at grain boundaries within a certain area of the observed metallographic structure And a step of measuring the length of the grain boundary precipitate in the crystal grain boundary direction, and the total value of the lengths of the minute cavities and the grain boundary precipitates generated in the certain area by adding the individual measured values Dividing by the total value of the length of the crystal grain boundary in a constant area or the constant area, the step of determining the grain boundary damage linear density and the grain boundary damage rate, and the grain boundary damage linear density previously obtained by a laboratory test, or The relationship between the grain boundary damage rate and the life consumption rate And a step of determining a life consumption rate of the austenitic heat-resisting steel by applying a constant value to the austenitic heat-resisting steel.
JP4189449A 1992-07-16 1992-07-16 High-temperature damage evaluation method for austenitic heat-resistant steel Expired - Fee Related JP3064107B2 (en)

Priority Applications (1)

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JP4189449A JP3064107B2 (en) 1992-07-16 1992-07-16 High-temperature damage evaluation method for austenitic heat-resistant steel

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Application Number Priority Date Filing Date Title
JP4189449A JP3064107B2 (en) 1992-07-16 1992-07-16 High-temperature damage evaluation method for austenitic heat-resistant steel

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JPH0634625A true JPH0634625A (en) 1994-02-10
JP3064107B2 JP3064107B2 (en) 2000-07-12

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Publication number Priority date Publication date Assignee Title
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JP4495888B2 (en) * 2000-08-28 2010-07-07 スネクマ Structural analysis methods for single crystal superalloys
JP2009145185A (en) * 2007-12-13 2009-07-02 Chugoku Electric Power Co Inc:The Creep lifetime evaluating method
JP2010101848A (en) * 2008-10-27 2010-05-06 Ihi Corp Damage evaluation method of high-chromium steel product
JP2013079917A (en) * 2011-10-05 2013-05-02 Chugoku Electric Power Co Inc:The Remaining life diagnosis apparatus for metal in which creep damage develops
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JP2015125116A (en) * 2013-12-27 2015-07-06 三菱日立パワーシステムズ株式会社 Heat resistant member inspection method
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WO2021135226A1 (en) * 2019-12-31 2021-07-08 北京科技大学 Method for displaying austenite grains of spring steel

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