PLEASE TAKE 100 SURFACE READINGS OF RESIDUAL STRESS, PEAK BROADENING, AND ASSOCIATED COLD WORK IN A SELECTE…

Public award description

PLEASE TAKE 100 SURFACE READINGS OF RESIDUAL STRESS, PEAK BROADENING, AND ASSOCIATED COLD WORK IN A SELECTED DIRECTION ON MULTIPLE FATIGUE SPECIMENS, AT ANGULAR LOCATIONS TO BE SPECIFIED. PLEASE USE ONLY ETHANOL CLEANING OF THE GAGE SURFACE FOR SURFACE PREPARATION. ASSUME NO SECTIONING OF MATERIAL IS REQUIRED FOR ACCESS TO THE MEASURED LOCATIONS. 2) RESIDUAL STRESSES VS. DEPTH SHALL BE THEN MEASURED USING X-RAY DIFFRACTION AT AN ANGULAR LOCATION TO BE SPECIFIED ON CERTAIN FATIGUE SPECIMENS, FOR A TOTAL OF 14 DEPTH PROFILES. A REPETITIVE PROCEDURE OF X-RAY MEASUREMENT, REMOVAL OF A LAYER OF MATERIAL OF KNOWN THICKNESS BY ELECTRO-POLISHING, AND X-RAY MEASUREMENT, ETC., SHALL BE PERFORMED TO GENERATE PROFILES OF RESIDUAL STRESS, PEAK BROADENING, AND ASSOCIATED COLD WORK VS. DEPTH FROM THE ORIGINAL SPECIMEN SURFACE. THE THICKNESS OF THE LAYER REMOVED SHALL BE 0.00075-0.001 . THE EFFECTS ON MEASURED RESIDUAL STRESS OF REMOVING THE LAYERS SHALL BE TAKEN INTO ACCOUNT AND COMPENSATED. THIS SHALL BE PERFORMED ON AN AUTOMATED MEASUREMENT/ELECTROPOLISHING RIG, IF POSSIBLE. THE DEGREE OF PEAK BROADENING AND ASSOCIATED COLD WORK SHALL ALSO BE RECORDED AS A FUNCTION OF DEPTH. PLEASE SAMPLE AT LEAST 10 DEPTHS IN THIS WAY FOR EACH DEPTH PROFILE. PLEASE ADVISE IF THE STRESS HAS NOT YET LEVELED OFF AT THAT POINT. ASSUME NO SECTIONING OF MATERIAL IS REQUIRED FOR ACCESS TO THE MEASURED LOCATIONS. PLEASE RETURN EACH SPECIMEN TO THEIR SEPARATE PACKAGE ACCORDING TO SPECIMEN IDENTIFICATION NUMBER. SHIP TO NASA GLENN RESEARCH CENTER, 21000 BROOKPARK RD., CLEVELAND, OH 44135 (ATTN. TIM GABB M.S. 49-3).