報告書番号

280065

タイトル（和文）

塩化物水溶液中におけるＳＵＳ３０４ステンレス鋼の腐食過程に対するＡＥ技法の適用

タイトル（英文）

AN APPLICATION OF AE TECHNIQUES TO THE CORROSION PROCESS IN CHLORIDE SOLUTION

概要 （図表や脚注は「報告書全文」に掲載しております）

本報告は，塩化物水溶液中での鋭敏化ＳＵＳ３０４ステンレス鋼（電気炉加熱および溶接鋭敏化材）の腐食試験にＡＥ技法を適用し，得られたＡＥデータに対して鋭敏化や腐食感受性の面から検討したものである。受入材および電気炉加熱鋭敏化材（６００Ｃ×１０Ｈ，６００Ｃ×１００Ｈ）での結果は以下の通りである。（１）腐食過程で発生するＡＥに関し，ＡＥ発生率は腐食反応が活発なほど大きな値をとる。（２）鋭敏化熱処理時間が長い程ＡＥ活動度は大きくなる。（３）６００Ｃ×１０Ｈ鋭敏化処理材が最も割れ感受性が高く，１００Ｈ鋭敏化処理材では割れ感受性に回復現象がみられる。一方，溶接鋭敏化材試料を用いた実験では，高温純水中低歪速度引張試験での試料の割れ発生位置と室温腐食試験での試料のＡＥ活動度の増加位置とがよい対応を示すことが明らかとなった。これらの結果は

概要 （英文）

CORROSION TESTS OF FURNACE-SENSITIZED AND WELD-SENSETIZED TYPE 304 STAINLESS STEEL WERE CONDUCTED BY IMMERSION OF SPECIMENS INTO ACID CHLORIDE SOLUTION. ACOUSTIC EMISSION CHARACTERISTICSDUE TO THE CORROSION REACTION WERE MEASURED DURING THE IMMERSION TEST.THE AE DATA OBTAINED FROM THESE EXPERIMENTS WERE DISCUSSED IN RELATIONWITH THE SENSITIZATION AND CORROSION SUSCEPTIBILITY OF TYPE 304 STAINLESS STEEL. THE RESULTS OF THE EXPERIMENTS WITH FURNACE-SENSITIZED SPECIMENS (AS-RECEIVED,600CX10HR,600CX100HR)WERE SUMMARIZED AS FOLLOWS;(1)AECOUNT RATE BECOMES HIGHER ACCORDING AS CORROSION REACTION BECOMES MOREACTIVE. (2)AS THE SENSITIZING TIME IS LONGER,AE ACTIVITY BECOMES HIGHER. (3)THE SPECIMEN SINSITIZED AT 600CX10HR SHOWS THE HIGHEST SCC SUSCEPTIBILITY AND THE HEALING EFFECT IS OBSERVED IN LONGEST TIME SENSITIZED (600CX100HR)SPECIMEN. IN THE WELD-SENSITIZED SPECIMENS,THE POSITION OF CRACK INITATION INTRODUCED BY MEANS OF SLOW STRAIN RATE TEST(SSRT)IN HIGH TEMPERATURE (288C)PURE WATER SHOWED A GOOD AGREEMENT WITH THE POSITION WHERE THE AE ACTIVITY INCREASE STEEPLY IN THE CORROSION TEST. THESE RESULTS SUGGEST THAT AE TECHNIQUE OF THIS TYPE IS APPLICABLE FOR THE EVALUATION OF THE DEGREE OF THE SENSITIZATION AND THE LOCAL CORROSION SUSCEPTIBILITY OF TYPE 304 STAINLESS STEEL.

報告者

キーワード