報告書番号

E282013

タイトル（和文）

LIFE TO CRACK INITIATION FROM NOTCH UNDER CREEP FATIGUE CONDITION IN A GAS-TURBINE DISK MATERIAL INCONEL 718

タイトル（英文）

LIFE TO CRACK INITIATION FROM NOTCH UNDER CREEP FATIGUE CONDITION IN A GAS-TURBINE DISK MATERIAL INCONEL 718

概要 （図表や脚注は「報告書全文」に掲載しております）

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概要 （英文）

FOR DEVELOPMENT OF A HIGH-EFFICIENCY GAS-TURBINE,IT IS NECESSARY TO IMPROVE THE RELIABILITY OF THE ELEVATED-TEMPERATURE DISK AS WELL AS COMBUSTOR,VANE AND BLADE. SINCE THE DISK HAS MANY NOTCHED PARTS, IT IS IMPORTANT TO ESTABLISH THE PREDICTION METHOD OF LIFE TO CRACK INITIATION FROM NOTCHES UNDER CREEP-FATIGUE CONDITION. HOWEVER,NEVERTHELESS THE CRACK INITIATION LIFE OF A HIGH STRENGTH MATERIAL-SUCH AS AN INCONEL 718 FORGING-IS AFFECTED BY THE TRANSITION FROM SMALLSCALE CREEP(SSC)TO LARGE SCALE CREEP(LSC),AND PREDICTION METHOD UNDER SUCH TRANSIENT CONDITION HAS NOT BEEN ESTABLISHED YET. SO,IN THIS STUDY,WE PROPOSE A PREDICTION METHOD OF LIFE TO CRACK INITIATION FROM A NOTCH UNDER THE TRANSIENT CONDITION FROM SSC TO LSC,AND USING INCONEL 718 FORGING FOR THE DISK MATERIAL,WE CONDUCTED STRESS CONTROLLED FATIGUE TESTS AT 923K UNDER VARIOUS CONDITION OF TENSION HOLD TIME,TH,ELASTIC STRESS CONCENTRATION FACTOR,KT,AND MAXIMUM NET SECTION STRESS. AS A RESULT,THE LIFE PREDICTED BY THE PROPOSED METHOD WAS FOUND TO AGREE WITH THE EXPERIMENTAL LIFE.

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