JPH0344660B2 - - Google Patents
Info
- Publication number
- JPH0344660B2 JPH0344660B2 JP59269895A JP26989584A JPH0344660B2 JP H0344660 B2 JPH0344660 B2 JP H0344660B2 JP 59269895 A JP59269895 A JP 59269895A JP 26989584 A JP26989584 A JP 26989584A JP H0344660 B2 JPH0344660 B2 JP H0344660B2
- Authority
- JP
- Japan
- Prior art keywords
- chromium
- molybdenum steel
- current density
- minimum current
- polarization curve
- 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.)
- Expired - Lifetime
Links
- 229910000831 Steel Inorganic materials 0.000 claims description 32
- 239000010959 steel Substances 0.000 claims description 32
- VNTLIPZTSJSULJ-UHFFFAOYSA-N chromium molybdenum Chemical compound [Cr].[Mo] VNTLIPZTSJSULJ-UHFFFAOYSA-N 0.000 claims description 27
- 230000010287 polarization Effects 0.000 claims description 18
- 238000000034 method Methods 0.000 claims description 17
- 230000032683 aging Effects 0.000 claims description 12
- 230000006866 deterioration Effects 0.000 claims description 11
- OXNIZHLAWKMVMX-UHFFFAOYSA-N picric acid Chemical compound OC1=C([N+]([O-])=O)C=C([N+]([O-])=O)C=C1[N+]([O-])=O OXNIZHLAWKMVMX-UHFFFAOYSA-N 0.000 claims description 7
- AUIXNZFZSGLHKP-UHFFFAOYSA-M sodium;2,3-dimethylbenzenesulfonate Chemical compound [Na+].CC1=CC=CC(S([O-])(=O)=O)=C1C AUIXNZFZSGLHKP-UHFFFAOYSA-M 0.000 claims description 7
- GVGUFUZHNYFZLC-UHFFFAOYSA-N dodecyl benzenesulfonate;sodium Chemical compound [Na].CCCCCCCCCCCCOS(=O)(=O)C1=CC=CC=C1 GVGUFUZHNYFZLC-UHFFFAOYSA-N 0.000 claims description 6
- 229940080264 sodium dodecylbenzenesulfonate Drugs 0.000 claims description 6
- 238000010408 sweeping Methods 0.000 claims description 6
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 4
- 229910052750 molybdenum Inorganic materials 0.000 claims description 4
- 239000011733 molybdenum Substances 0.000 claims description 4
- 239000000463 material Substances 0.000 description 15
- 239000003792 electrolyte Substances 0.000 description 8
- 239000007864 aqueous solution Substances 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 239000008151 electrolyte solution Substances 0.000 description 4
- 238000002161 passivation Methods 0.000 description 3
- 230000007704 transition Effects 0.000 description 3
- 239000011651 chromium Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 238000002848 electrochemical method Methods 0.000 description 2
- 238000009863 impact test Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000007429 general method Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- GKOFYDFXPCSWBM-UHFFFAOYSA-M sodium;2,3,4-trimethylbenzenesulfonate Chemical compound [Na+].CC1=CC=C(S([O-])(=O)=O)C(C)=C1C GKOFYDFXPCSWBM-UHFFFAOYSA-M 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
-
- 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
- G01N17/02—Electrochemical measuring systems for weathering, corrosion or corrosion-protection measurement
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Biodiversity & Conservation Biology (AREA)
- Ecology (AREA)
- Environmental & Geological Engineering (AREA)
- Environmental Sciences (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Testing Resistance To Weather, Investigating Materials By Mechanical Methods (AREA)
- Investigating And Analyzing Materials By Characteristic Methods (AREA)
Description
本発明はクロム・モリブデン鋼の経年劣化判定
方法に関し、詳しくは高温で使用されるクロム・
モリブデン鋼の構造部材の経年劣化の程度を、非
破壊的にしかも高い精度にて判定することのでき
る方法に関する。
一般に、石油精製等の化学工業をはじめとする
様々な工業分野では、300〜600℃の高温でもすぐ
れた機械的性質を有するクロム・モリブデン鋼
が、各種の構造部材（化学プラントの反応器、熱
交換器その他の塔槽類、加熱炉チユーブその他の
配管類、タービンのローター、ケーシング等の原
動機部材）に広く用いられている。
このような構造部材は、高温下で長期間操業さ
れることにより経年的材質変化を招く場合がある
ことが知られている。この材質変化には大別して
脆化と軟化があるが、特に、脆化が起ると材料の
靭性低下を招き、構造部材の損傷につながる危険
をはらんでいる。
そのため上記の構造部材は定期的に検査を行う
ことが必要である。
一般的に、構造部材の脆化を判定する方法とし
ては、シヤルピー衝撃試験を行つてシヤルピー破
面遷移温度差（ΔFATT）を求め、これを指標と
して判定する方法が確立されている。この方法は
精度も高く、またその信頼性も高いものである
が、試験のために構造部材の一部を切り取ること
が必要であり、そのため実用にはほとんど供しえ
ないものである。
そこで近年に至つて、構造部材を切り取ること
なく、経年劣化を判定できる方法として電気化学
的な手法が開発されてきている（特開昭57−
142540号公報、実開昭57−138051号公報）。
しかし、この一般的手法をクロム・モリブテン
鋼に具体的に適用するための技術は確立されてい
なかつた。
そこで本発明者らは、基本的には上述の電気化
学的な手法を用いて、構造部材として使用されて
いるクロム・モリブテン鋼の経年劣化を、高い精
度ならびに信頼性にて判定できる方法を開発すべ
く鋭意研究を重ねた。その結果、高温における構
造部材として使用されているクロム・モリブデン
鋼を試料電極として一定濃度のピクリン酸とドデ
シルベンゼンスルフオン酸ナトリウムあるいはジ
メチルベンゼンスルフオン酸ナトリウムを含む水
溶液よりなる電解液に浸漬し、自然電位から貴方
向に掃引し、不働態電位で保持したのち逆方向に
掃引することにより該クロム・モリブデン鋼の分
極曲線を作成する際における、前記逆方向への掃
引時の最小電流密度が劣化判定の指標となること
を見出した。本発明はかかる知見に基いて完成し
たものである。
すなわち本発明は、高温における構造部材とし
て使用されているクロム・モリブデン鋼の分極曲
線を、該構造部材を試料電極として(a)ピクリン酸
0.15〜0.6重量％および(b)ドデシルベンゼンスル
フオン酸ナトリウムあるいはジメチルベンゼンス
ルフオン酸ナトリウム0.07〜0.3重量％を含有す
る水溶液よりなる電解液に浸漬し、自然電位から
貴方向に掃引し、不働態電位で保持したのち逆方
向に掃引することにより該クロム・モリブデン鋼
の分極曲線を作成する際における、前記逆方向へ
の掃引時の最小電流密度を標準試料について同様
にして求めた最小電流密度と比較して判定するこ
とを特徴とするクロム・モリブデン鋼の経年劣化
判定方法を提供するものである。
本発明の方法では、構造部材とて使用されてい
るクロム・モリブデン鋼の分極曲線を作成する
が、この分極曲線の作成手順、器具等については
公知の技術、たとえば実開昭57−138051号公報な
どに従えばよい。しかし、この分極曲線を作成す
るにあたつて、本発明の方法では電解液として(a)
ピクリン酸0.15〜0.6重量％、好ましくは0.2〜0.4
重量％、さらに好ましくは0.22〜0.32重量％およ
び(b)ドデシルベンゼンスルフオン酸ナトリウムま
たはジメチルベンゼンスルフオン酸ナトリウム
0.07〜0.3重量％、好ましくは0.07〜0.2重量％、
さらに好ましくは0.08〜0.15重量％含有する水溶
液を用いることが必要である。
本発明者らは、この電解液を選定するにあたつ
ては、分極曲線の作成に際して、脆化していな
いクロム・モリブデン鋼あるいは脱脆化処理を施
したクロム・モリブデン鋼（標準試料）では、逆
掃引時、すなわち貴方向から自然電位の方向への
掃引時の最小電流密度が零になること、および
脆化したクロム・モリブデン鋼の逆掃引時の最小
電流密度ができるだけ大きい値として得られるこ
との二点を基準として、様々な電解液を試みた。
その結果として、上述したような水溶液が最も好
都合であることを見出したのである。
また本発明の方法は、上述した如き特定の電解
液を用いるとともに、逆掃引時の最小電流密度を
クロム・モリブデン鋼の経年劣化判定の指標とす
る点にその特徴が存する。
本発明者らの実験によれば、この逆掃引時の最
小電流密度は、シヤルピー衝撃試験で得られるシ
ヤルピー破面遷移温度差（ΔFATT）と非常に強
い相関が認められている。したがつて、この
ΔFATTが構造部材の経年劣化を示す指標として
既に高い信頼性が認められていることから、最小
電流密度を指標とすることによつても、経年劣化
の判定を高い信頼性にて行うことができるわけで
ある。
本発明の方法によつて作成されるクロム・モリ
ブデン鋼の分極曲線は、脱脆化処理されたクロ
ム・モリブデン鋼の場合は第１図の如くであり、
脆化しているクロム・モリブデン鋼の場合は第２
図の如くである。つまり、測定すべき試料電極を
電解液中に５分間程浸漬した後、自然電位Ａから
貴方向に掃引し、不働態電位Ｃで２分間程度保持
した後、再び同じ速度で逆方向へ掃引することに
より、分極曲線が作成される。ここで、逆掃引時
には電流密度の極小値Ｄをもつが、これは不働態
化電位Ｂで形成され始めた不働態化被膜がさらに
強固に形成されるためと考えられる。
なお、この逆掃引時の電流密度の極小値Ｄを最
小電流密度と呼ぶが、脱脆化材（第１図）と脆化
材（第２図）の最小電流密度を比較すると、脱脆
化材ではほぼ零であるのに対して、脆化材ではは
つきりと正の値を示している。これは、再不働態
化域で形成される被膜が脱脆化材では試料全面に
わたつて均一に形成されるが、脆化材では粒界に
偏析したリン等の不純物の影響で被膜形成が抑制
され、その結果、電流が流れやすくなるためであ
ろうと考えられる。また、分極後の試料表面の顕
微鏡観察によれば、脆化材では粒界に沿つて選択
的に溶解されるが、脱脆化材では粒界に沿つた選
択的溶解は観察されない。
以上のことから、逆掃引時の最小電流密度を測
定すれば、クロム・モリブデン鋼の経年劣化、即
ち脆化の状態を判定することができるわけであ
る。しかも、この最小電流密度が前述のシヤルピ
ー破面遷移温度差（ΔFATT）と強い相関がある
ことから、判定の信頼性も著しく高い。さらに、
電解液として(a)ピクリン酸0.15〜0.6重量％およ
び(b)ドデシルベンゼンスルフオン酸ナトリウムあ
るいはジメチルベンゼンスルフオン酸ナトリウム
0.07〜0.3重量％を含有する水溶液が用いられて
いるため、クロム・モリブデン鋼の脆化の程度に
応じて、最小電流密度の値が非常に高感度に表示
される。従つて、脆化判定の精度も著しく高い。
この電解液の代わりに他の電解液、例えば(a)，
(b)成分の濃度が上記範囲外のものや(b)成分として
トリメチルベンゼンスルフオン酸ナトリウムを用
いたものでは、脆化材の逆掃引時の最小電流密度
が大きな値とならず、脆化判定の精度が低いもの
となる。あるいは脱脆化材の最小電流密度が零に
ならなかつたり、測定に著しく長い時間を要した
り、さらには再現性に乏しく判定の信頼性に欠け
るなど、様々な不都合が生じる。
叙上の如く、本発明の方法によれば、クロム・
モリブデン鋼の構造部材の経年劣化を、非破壊的
かつ高信頼性ならびに高感度、高精度にて判定す
ることができる。しかも、用いる電解液の調製が
容易であると同時に、短時間かつ簡単な測定操作
にて脆化の判定をすることができる。
したがつて、本発明の方法によれば、化学プラ
ント等の各種工業の構造部材として用いられるク
ロム・モリブデン鋼の経年劣化の程度を正確に把
握できるため、その構造部材の余寿命の評価や操
業条件の選定等に貴重なデータを提供する。
次に本発明を実施例によりさらに詳しく説明す
る。
実施例１〜13および比較例１〜９
経年劣化の構造部材として、化学プラントの蒸
気用配管として540℃で14年間使用された１ 1/4
Cr−1/2Mo鋼を用いた。その化学組成はCr：
1.23、Mo：0.48、Ｃ：0.18、Si：0.19、Mn：
0.64、Ｐ：0.046、Ｓ：0.011（単位は重量％）であ
る。この部材を試料電極として、分極曲線を作成
した。
分極曲線は、まず上記の試料電極を、所定濃度
のピクリン酸とドデシルベンゼンスルフオン酸ナ
トリウムを溶解した水溶液よりなる電解液中に５
分間浸漬した後、自然電位から貴方向に掃引し、
不働態電位で２分間保持した後、再び同じ速度で
逆方向へ掃引することにより作成した。ここで得
られた逆掃引時の最小電流密度（Ir）を第１表に
示す。
また、脱脆化処理したクロム・モリブデン鋼に
ついても上記と同様にして分極曲線を作成した。
ここで得られた逆掃引時の最小電流密度（Ir）が
零であるか否かを第１表に示す。
The present invention relates to a method for determining aging of chromium-molybdenum steel, and more specifically, chromium-molybdenum steel used at high temperatures.
The present invention relates to a method capable of non-destructively and highly accurately determining the degree of aging deterioration of structural members made of molybdenum steel. In general, in various industrial fields including the chemical industry such as oil refining, chromium-molybdenum steel, which has excellent mechanical properties even at high temperatures of 300 to 600 degrees Celsius, is used for various structural components (chemical plant reactors, thermal It is widely used in exchangers and other towers and tanks, heating furnace tubes and other piping, and prime mover parts such as turbine rotors and casings. It is known that such structural members may undergo material changes over time due to long-term operation at high temperatures. This change in material properties can be broadly classified into embrittlement and softening, but especially when embrittlement occurs, the toughness of the material decreases, which poses the risk of damaging structural members. Therefore, it is necessary to periodically inspect the above-mentioned structural members. Generally, as a method for determining the embrittlement of a structural member, a method is established in which a Charpy impact test is performed to obtain the Charpy fracture transition temperature difference (ΔFATT), and this is used as an index for determination. Although this method is highly accurate and reliable, it requires cutting out a portion of the structural member for testing, so it is almost impractical for practical use. Therefore, in recent years, electrochemical methods have been developed as a method for determining aging deterioration without cutting out structural members (Japanese Unexamined Patent Application Publication No. 1987-
142540, Utility Model Application Publication No. 138051/1983). However, no technology has been established to specifically apply this general method to chromium-molybdenum steel. Therefore, the present inventors developed a method that can determine the aging deterioration of chromium-molybdenum steel used as structural members with high accuracy and reliability, basically using the electrochemical method described above. I did as much research as possible. As a result, chromium-molybdenum steel, which is used as a structural member at high temperatures, was immersed as a sample electrode in an electrolytic solution containing a fixed concentration of picric acid and sodium dodecylbenzenesulfonate or sodium dimethylbenzenesulfonate. When creating a polarization curve for the chromium-molybdenum steel by sweeping from the natural potential in the noble direction, holding it at a passive potential, and then sweeping in the reverse direction, the minimum current density during the reverse sweep is degraded. We found that it can be used as an indicator for judgment. The present invention was completed based on this knowledge. That is, the present invention calculates the polarization curve of chromium-molybdenum steel used as a structural member at high temperatures by using the structural member as a sample electrode and (a) picric acid.
0.15 to 0.6% by weight and (b) sodium dodecylbenzenesulfonate or sodium dimethylbenzenesulfonate 0.07 to 0.3% by weight. When creating a polarization curve for the chromium-molybdenum steel by holding it at a potential and then sweeping it in the opposite direction, the minimum current density at the time of sweeping in the opposite direction is the same as the minimum current density obtained for the standard sample. The present invention provides a method for determining aging deterioration of chromium-molybdenum steel, which is characterized by comparative determination. In the method of the present invention, a polarization curve of chromium-molybdenum steel used as a structural member is created, but the procedure and equipment for creating this polarization curve are known from known techniques, such as those disclosed in Japanese Utility Model Application No. 57-138051. All you have to do is follow. However, in creating this polarization curve, in the method of the present invention, (a) is used as the electrolyte.
Picric acid 0.15-0.6% by weight, preferably 0.2-0.4
% by weight, more preferably 0.22-0.32% by weight and (b) sodium dodecylbenzenesulfonate or sodium dimethylbenzenesulfonate
0.07-0.3% by weight, preferably 0.07-0.2% by weight,
More preferably, it is necessary to use an aqueous solution containing 0.08 to 0.15% by weight. In selecting this electrolyte, the present inventors determined that when creating a polarization curve, for non-embrittled chromium-molybdenum steel or de-embrittled chromium-molybdenum steel (standard sample), The minimum current density during the reverse sweep, that is, the sweep from the noble direction to the direction of the natural potential, should be zero, and the minimum current density during the reverse sweep of embrittled chromium-molybdenum steel should be obtained as large as possible. We tried various electrolytes based on these two points.
As a result, it has been found that aqueous solutions such as those mentioned above are most convenient. Further, the method of the present invention is characterized in that it uses the above-mentioned specific electrolyte and uses the minimum current density during reverse sweep as an index for determining aging of chromium-molybdenum steel. According to experiments conducted by the present inventors, it has been recognized that the minimum current density during this reverse sweep has a very strong correlation with the difference in Shallpy fracture transition temperature (ΔFATT) obtained in the Shallpy impact test. Therefore, since this ΔFATT has already been recognized as highly reliable as an indicator of aging deterioration of structural members, using the minimum current density as an indicator also makes it possible to determine aging deterioration with high reliability. In other words, it can be done. The polarization curve of chromium-molybdenum steel prepared by the method of the present invention is as shown in Fig. 1 in the case of deembrittled chromium-molybdenum steel.
In the case of brittle chromium-molybdenum steel, the second
As shown in the figure. In other words, the sample electrode to be measured is immersed in the electrolytic solution for about 5 minutes, then swept in the noble direction from the natural potential A, held at the passive potential C for about 2 minutes, and then swept in the opposite direction again at the same speed. By doing this, a polarization curve is created. Here, during the reverse sweep, the current density has a minimum value D, but this is thought to be because the passivation film that began to be formed at the passivation potential B is formed even more firmly. The minimum value D of the current density during this reverse sweep is called the minimum current density, but when comparing the minimum current densities of the de-embrittled material (Fig. 1) and the embrittled material (Fig. 2), it is found that While it is almost zero for materials, it shows a sharply positive value for embrittled materials. This is because the film formed in the re-passivation region is uniformly formed over the entire surface of the sample in the deembrittled material, but in the case of the embrittled material, film formation is suppressed due to the influence of impurities such as phosphorus segregated at the grain boundaries. This is thought to be because the current flows more easily as a result. Moreover, according to microscopic observation of the sample surface after polarization, selective dissolution along grain boundaries is observed in the embrittling material, but selective dissolution along the grain boundaries is not observed in the deembrittling material. From the above, by measuring the minimum current density during reverse sweep, it is possible to determine the state of aging deterioration, that is, embrittlement, of chromium-molybdenum steel. Furthermore, since this minimum current density has a strong correlation with the aforementioned Sharpy fracture transition temperature difference (ΔFATT), the reliability of the determination is also extremely high. moreover,
As an electrolyte, (a) 0.15 to 0.6% by weight of picric acid and (b) sodium dodecylbenzenesulfonate or sodium dimethylbenzenesulfonate.
Since an aqueous solution containing 0.07 to 0.3% by weight is used, the value of the minimum current density is displayed with very high sensitivity depending on the degree of embrittlement of the chromium-molybdenum steel. Therefore, the accuracy of embrittlement determination is also extremely high. Instead of this electrolyte, other electrolytes, such as (a),
If the concentration of component (b) is outside the above range or if sodium trimethylbenzenesulfonate is used as component (b), the minimum current density during the reverse sweep of the embrittlement material will not be large, resulting in embrittlement. The accuracy of the judgment will be low. Alternatively, various inconveniences occur, such as the minimum current density of the deembrittling material not becoming zero, the measurement taking an extremely long time, and furthermore, the reproducibility is poor and the reliability of the determination is poor. As mentioned above, according to the method of the present invention, chromium
The aging deterioration of molybdenum steel structural members can be determined non-destructively with high reliability, high sensitivity, and high accuracy. Moreover, the electrolytic solution used is easy to prepare, and at the same time, embrittlement can be determined in a short time and with a simple measurement operation. Therefore, according to the method of the present invention, the degree of aging deterioration of chromium-molybdenum steel used as structural members in various industries such as chemical plants can be accurately grasped, so that evaluation of the remaining life of the structural members and operation Provides valuable data for selecting conditions, etc. Next, the present invention will be explained in more detail with reference to Examples. Examples 1 to 13 and Comparative Examples 1 to 9 1 1/4 used as a structural member for aged deterioration and as steam piping in a chemical plant for 14 years at 540°C
Cr-1/2Mo steel was used. Its chemical composition is Cr:
1.23, Mo: 0.48, C: 0.18, Si: 0.19, Mn:
0.64, P: 0.046, S: 0.011 (units are weight %). A polarization curve was created using this member as a sample electrode. The polarization curve is calculated by first placing the above sample electrode in an electrolyte solution consisting of an aqueous solution containing picric acid and sodium dodecylbenzenesulfonate at a predetermined concentration.
After soaking for a minute, sweep from the natural potential in the upward direction,
After holding at the passive potential for 2 minutes, the sample was created by sweeping in the opposite direction at the same speed again. Table 1 shows the minimum current density (Ir) during reverse sweep obtained here. In addition, a polarization curve was created in the same manner as above for chromium-molybdenum steel that had been subjected to deembrittlement treatment.
Table 1 shows whether the minimum current density (Ir) during reverse sweep obtained here is zero or not.
【表】【table】
【表】
実施例 14
上記実施例において、電解液としてピクリン酸
0.25重量％およびジメチルベンゼンスルフオン酸
ナトリウム0.1重量％を含有する水溶液を用いた
こと以外は、上記実施例と同様の操作を行つた。
その結果、経年劣化材のIrは3.2μA／cm2であり、
また脱脆化材のIrは０であつた。[Table] Example 14 In the above example, picric acid was used as the electrolyte.
The same operation as in the above example was carried out except that an aqueous solution containing 0.25% by weight and 0.1% by weight of sodium dimethylbenzenesulfonate was used.
As a result, the Ir of the aged material was 3.2μA/ cm2 ,
Further, the Ir content of the deembrittling material was 0.
第１図は脱脆化処理されたクロム・モリブデン
鋼の分極曲線を示し、第２図は脆化したクロム・
モリブデン鋼の分極曲線を示す。
Figure 1 shows the polarization curve of deembrittled chromium-molybdenum steel, and Figure 2 shows the polarization curve of embrittled chromium-molybdenum steel.
The polarization curve of molybdenum steel is shown.
Claims (1)
クロム・モリブデン鋼の分極曲線を、該クロム・
モリブデン鋼を試料電極として(a)ピクリン酸0.15
〜0.6重量％および(b)ドデシルベンゼンスルフオ
ン酸ナトリウムあるいはジメチルベンゼンスルフ
オン酸ナトリウム0.07〜0.3重量％を含有する水
溶液よりなる電解液に浸漬し、自然電位から貴方
向に掃引し、不働態電位で保持したのち逆方向に
掃引することにより該クロム・モリブデン鋼の分
極曲線を作成する際における、前記逆方向への掃
引時の最小電流密度を標準試料について同様にし
て求めた最小電流密度と比較して判定することを
特徴とするクロム・モリブデン鋼の経年劣化判定
方法。1 The polarization curve of chromium-molybdenum steel, which is used as a structural member at high temperatures, is
Using molybdenum steel as a sample electrode (a) Picric acid 0.15
~0.6% by weight and (b) sodium dodecylbenzenesulfonate or sodium dimethylbenzenesulfonate (b) 0.07~0.3% by weight of sodium dimethylbenzenesulfonate. When creating a polarization curve for the chromium-molybdenum steel by holding it at 100 m and then sweeping it in the reverse direction, compare the minimum current density during the reverse sweep with the minimum current density similarly determined for the standard sample. A method for determining aging deterioration of chromium-molybdenum steel.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59269895A JPS61148362A (en) | 1984-12-21 | 1984-12-21 | Decision on aging in chrome-molybdenum steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59269895A JPS61148362A (en) | 1984-12-21 | 1984-12-21 | Decision on aging in chrome-molybdenum steel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61148362A JPS61148362A (en) | 1986-07-07 |
| JPH0344660B2 true JPH0344660B2 (en) | 1991-07-08 |
Family
ID=17478711
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59269895A Granted JPS61148362A (en) | 1984-12-21 | 1984-12-21 | Decision on aging in chrome-molybdenum steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61148362A (en) |
-
1984
- 1984-12-21 JP JP59269895A patent/JPS61148362A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61148362A (en) | 1986-07-07 |
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