February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 1 HPT Blade - Overview • Blade configuration • Trailing edge root cracks • Shank separation • Airfoil separation • Trailing edge separations February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 2 2002M52P05 N5 Full Wrap TBC Improved Film Cooling Intro. 1997 -7 Baseline -5B/P S/B 72-163 2002M52P09/P11/P14 N5 P09 Full Wrap TBC P11 1/2 Wrap TBC Platform Cooling P14 same as P11 with Thinned Shank Coating Intro. 1999 -7 S/B 72-115/116 -5B/P S/B 72-271 N5 P11 plus optimized T/E cooling Shank improvements Production Intro. 4Q 2001 1957M10P01 CFM56 HPT 3D Aero Blade Configurations 2002M52P04 N5 Full Wrap TBC Intro. 1994 -5B/P Baseline February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 3 HPT Blade Root Trail Edge Cracks February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 4 HPT Blade Root Trailing Edge Cracks BACKGROUND • Early blade design have exhibited root trail edge cracks in service - 2002M52P04 and P05 HPT blades affected + 373 -7B engines delivered with P05 blades • No CFM56-7 engines delivered with P04 blades + 29 -5B/P engines delivered with P04 blades • 207 -5B/P engines delivered with P05 blades • No IFSD’s • 39 UER’s (35 for -5B/P; 4 for -7) - Detailed borescope inspection effective February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 5 HPT Blade Root Trailing Edge Cracks 2002M52P04/P05 Area of root trailing edge crack initiation and propagation February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 6 Reduced Borescope Inspection Program Proven to be Very Effective HPT Blade Root Trailing Edge Cracks • Containment program - borescope inspection - Focused inspection required for detection + Training video produced and distributed to all customers + Fleet Highlites articles written to increase awareness + Contact CFMI if assistance required with training • Service Bulletins issued for borescope inspection - -7B S/B 72-326 -- Issued June 2001 + 2002M52P05 blade only - Reduced borescope inspection intervals - every 1000 cycles February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 7 Typical TE Crack Indication HPT Blade Root Trailing Edge Cracks Borescope • On-Wing Maintenance Manual Limits for Root Trailing Edge Cracks - Every 400 cycles if crack is less than 0.120 inch (3,0 mm) - Every 200 cycles if crack is between 0.120 and 0.200 inch (3,0 to 5,1 mm) - 40 cycle over-service extension if crack is between 0.200 and 0.300 inch (5,1 to 7,6 mm) February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 8 HPT Blade Root Trailing Edge Cracks • Corrective action program - 2002M52P09 / P11 blade introduced in 1999 + Factory endurance testing has demonstrated 3X improvement in T/E root airfoil capability over the P04/P05 - 2002M52P04/P05 blade retirement program at next shop visit + -7B S/B 72-115 revised June 2001 - Category 4 • Logistic plan in place • Special procedure developed to change blades - ESM 72-00-52, Special Procedure 002 - Shop visit not required in most cases - Replace all 80 blades without removal of HPT disk using pre-ground, balanced blades - December 2001 Fleet Highlites article introduced procedure February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 9 • Further durability improvements - 1957M10P01 HPT blade - 9000 accelerated development engine cycles…. no visible cracks. Testing continuing. • Production introduction (SAC) 888-767, -772, -773, -776, -777, 779, - 780 through -793, -795 and up. • Production introduction (DAC) 876-757 and up • HPT blade kit PN 737L325G03 available April 2002 - Kit contains a set of 80 pre ground HPT blade PN 1957M10P01, balanced and numbered blades P01 Factory Testing Demonstrating Further Improvement in Trail Edge Crack Capability HPT Blade Root Trailing Edge Cracks February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 10 Enhanced HPT Blade P/N 1957M10P01 Reduced row 1 flow (13 vs. 19 holes) Extend row 8 to platform (added 1 hole) Add 4 holes to root Uniform row 8 spacing Reduced size trailing edge slots (0.040 to 0.033”) Pressure side cooling near the platform Major Features same as P11 • N5 Material • Optimized cooling • Pt-Al base coat • TBC on pressure side Smoothed internal shank cooling passage geometry with same thinned internal coating as P14 blade February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 11 CFM56 3D Aero HPT Blade Shank Separation February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 12 HPT Blade Shank Cracking • CFM56-5B6/2P IFSD - November 2000 - Contained - TSN / CSN = 9027 / 8745 - HPT Blade separated in blade shank + HPT Blade PN 2002M52P04 + One other shank separation due to secondary damage + Other blade airfoils separated due to secondary damage Event Description February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 13 • Only shank separation event to date - 3100 engines in 5B/P and -7B fleets - Over 9 million cycles HPT Blade Shank Cracking H P T 3D Ae ro F le e t 0 5 0 1 0 0 1 5 0 2 0 0 2 5 0 3 0 0 3 5 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 7500 8000 8500 9000 9500 10000 10500 C SN Qty C FM 5 6 -5B /P C FM 5 6 -7B Event February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 14 BACKGROUND • HPT blade is a single crystal N5 material, with an aluminide internal coating - Coating reduces oxidation/corrosion - Three coating processes used + All three coating processes within specification + Coating thickness correlates with process • Coating thickness affects LCF initiation - Verified via laboratory specimen testing - Thinner coating better • Cracking initiated at high stress location - Cooling cavity transition HPT Blade Shank Cracking February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 15 Cross Sectional View of Cooling Cavity Local stress riser at transition 0.420 inch (10,7 mm) HPT Blade Shank Cracking February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 16 Metallurgical Investigation • Initiated at mid-cooling passage – Initiation / propagation in Low Cycle Fatigue (LCF) – Transitioned to crystallographic fatigue – Shank geometry common to all 2002M52P04 through P14 blade part numbers Crack Location Cross sectional view of cooling cavity Primary blade Separation Secondary blade separation (Tensile overload) HPT Blade Shank Cracking February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 17 • Nine engines removed to sample high-cycle blades - Five CFM56-5B/P (up to 7599 CSN) - Four CFM56-7B (up to 9050 CSN) - Two of the three coating processes represented + Limited data from second process + Blades from third process too young for meaningful data • Findings - Approximately 4125 blades inspected + Sampling engines plus routine shop visits + Visual, eddy current, and metallurgical - 237 blades have been found with shank cracks + All cracked blades from process that yields thickest coating + All cracks detected using Eddy Current probe & verified by cut up Field Investigation Cracking Not as Severe as Originally Estimated HPT Blade Shank Cracking February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 18 • Blade Design Changes • Blade Rework • Test Program • Field Recommendations HPT Blade Shank Cracking February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 19 • Interim action taken: - PN 2002M52P14 blade released + CFM56-5B/P SB 72-0400 • ESN Intro.: 575-233 and up + CFM56-7B SB 72-0337 • ESN Intro.: 889-505 and up • 888-477, -496 through -497, -503 and up - Thinner internal coating in shank area • New blade introduced, PN 1957M10P01 - Phased production introduction started in 4th quarter 2001 - Same coating process as P14 blade - Redesigned internal casting geometry to reduce stress - Service Bulletin to release to field April 2002 Blade Design Changes HPT Blade Shank Cracking February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 20 Blade Rework • CFM has developed strip process for blade coating removal. Steps: - Inspect for internal cracking with Eddy Current probe - Strip process to remove internal coating - External coating rejuvenation/tip repair - Re-identify to new part number • Estimate 2Q02 availability HPT Blade Shank Cracking Test Program • Factory engine test cyclic endurance testing on-going - Mix of field returned high cycle blades, redesigned blades, reworked blades - Data to supplement field data - Completes 2Q02 February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 21 Field Recommendations • No change to current maintenance recommendations - No on-wing inspection possible (internal coating) - At SV process per ESM and applicable SB’s • Update on field findings and metallurgical evaluation to be provided as data accumulates - Continue to evaluate blades returned from routine shop visits - Continue detailed metallurgical evaluations of blades + Including data from the other coating processes • Establish field recommendations based on field returned blade findings - Coating process - Engine model / rating differences - Data supplemented by factory engine test HPT Blade Shank Cracking February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 22 CFM56-5BP/-7 HPT Blade Airfoil Separation February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 23 Events HPT Blade Airfoil Separations • Four airfoil separation events, one CFM56-5B/P, three CFM56-7B - Time, cycle and thrust ratings vary - All engines were first run Event date Model ESN Rating TSN CSN Part Number May 2000 -7B 875-256 B22 5057 3265 2002M52P05 Nov 2000 -7B 874-163 B24 6401 6164 2002M52P05 Feb 2001 -7B 876-561 B26 769 1006 2002M52P11 Jul 2001 -5B/P 779-384 B3 1567 758 2002M52P05 • Events have similar overall characteristics -5B/P -7B - Airfoils separated just above platform - No evidence of abnormal operation - No evidence of combustor involvement - No source of fatigue stimulus identified - No evidence of manufacturing related cause February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 24 HPT Blade Airfoil Separation Rupture Tensile overload LCF HCF Potential Root Cause Flowchart Eliminated Probability Potential Separation Mechanisms Scenarios Low High Medium • Pre existing trail edge root cracks • Material pedigree • Coating impact (internal cracks) • Local stress exceeds material capability • DOD/FOD • Loss of cooling flow • Plugging in blade • Plugging in inducer • Loss of retainer sealing • Material pedigree • Pre existing cracks/missing material (frequency shift) • Material pedigree • Coating impact (internal cracks) • Loss of damping • High mean stress • Vibratory stimulus • HPT nozzle area • Combustor profile/pattern • Fuel staging • Fuel nozzle flow • LPT nozzle area • TBV scheduling • Secondary flow circuit HPT Blade Airfoil Separations Telemetry testing to investigate February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 25 • Telemetry test conducted to measure blade vibratory stress levels under various engine operating conditions - 35 of 80 blades instrumented; 5 different gage locations - Over 25 hours testing completed November ‘01 including 60 transients - Overall, blade responses similar to previous tests …however: • One blade had higher than expected response on blade tip gage after throttle burst to take-off speed conditions - Response lagged 10-15 seconds after target speed reached - Would result in high vibratory stress in failure location - Response not seen on other blades with same gage location Investigation Status HPT Blade Airfoil Separations Unusual blade vibratory response measured in telemetry testing February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 26 • CFMI working to understand single blade response - Telemetry instrumentation re-validated post-test - Analysis being conducted to support single blade response - Detailed characterization of blade (frequencies, geometry) - Second build of telemetry engine likely Investigation Status HPT Blade Airfoil Separations Time Lag February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 27 CFM56-5BP/-7 HPT Blade Trailing Edge Separation February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 28 6 Events of HPT blades with missing trailing edge material • Missing HPT blade material observed on factory endurance engine 779-193/4a • 5 events reported from the field ESN Blade PN PTSN PCSN 779311 2002M52P05 9025 3968 779318 2002M52P05 7942 5002 779299 2002M52P05 8452 5274 874494 2002M52P09 9403 3249 875240 2002M52P05 10459 3772 Root Cause Identified • Metallurgical investigation determined that an LCF crack initiated on the inside wall of passage 8 of the airfoil • Crack propagated to liberate blade trailing edge material • Crack initiation was due to a high stress concentration that resulted from a sharp corner that was machined into the blade core Trailing Edge Separation Radial Crack Found During Routine BSI, no Reports of indications Vibration, Minor Downstream Damage February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 29 Trailing Edge Separation Manufacturing Changes Manufacturing process was immediately changed to preserve the low stress core generated radius in cavity 8 Parts shipped after January 1999 were produced with the improved manufacturing process change Blades with the manufacturing process change have exceeded 7500 factory endurance cycles to date without cracks. Status • CFMI working to identify affected population through manufacturing records review • Updates will be provided during routine WTT calls • No field recommendation at this time February 2002 WTT face to face CFMI / Boeing Proprietary Information - Unauthorized Disclosure, Use, or Export are Prohibited 30 • Root Trail Edge Cracking - Limited to P05 initial production blades; 373 engines - Field plan in place for in-service inspection and replacement at shop visit - Improved designs available • Shank Cracking - One event in over 9 million hours in CFM56 3D aero HPT blade fleet - Root cause understood; cracking due to material property degradation from coating - Factory engine testing, field blade retrieval on-going to characterize coating populations and life capabilities - No field action required at this time • Airfoil Separations - Four events in -5B/P and -7 fleets - Telemetry testing has identified potential root cause; analysis underway - additional testing planned - No field action required at this time • Trailing Edge Separations - Root cause identified, improved processes incorporated - CFMI working to identify affected population - CFMI will continue to update at WTT calls Summary HPT Blade作者: kinran 时间: 2011-6-4 23:25:40
