CFM56-7 HPT Blade HPT Blade - Overview • Blade Configuration • Trailing Edge Root Cracks • Shank Separation • Airfoil Separation • Trailing Edge Separation CFM56-5C China All Operators Meeting 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 3 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 -7SB 72-0351 -5B/P 72-422 1957M10P01 CFM56 HPT 3D Aero Blade Configurations 2002M52P04 N5 Full Wrap TBC Intro. 1994 -5B/P Baseline HPT Blade Root Trail Edge Cracks CFM56-5C China All Operators Meeting 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 5 HPT Blade Root Trailing Edge Cracks Background • Early blade designs 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 IFSDs • 45 UERs (35 for -5B/P; 10 for -7) - Detailed borescope inspection effective CFM56-5C China All Operators Meeting 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 6 HPT Blade Root Trailing Edge Cracks 2002M52P04/P05 Area of root trailing edge crack initiation and propagation CFM56-5C China All Operators Meeting 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 7 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 CFM if assistance required with training • Service Bulletins issued for borescope inspection - CFM56-7B S/B 72-326 -- Issued June 2001 - 2002M52P05 blade only - CFM56-5B/P S/B 72-098 -- Revised Sept. 1998 - 2002M52P04 and P05 blades only - Reduced borescope inspection intervals - every 1000 cycles CFM56-5C China All Operators Meeting 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 8 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) CFM56-5C China All Operators Meeting 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 9 HPT Blade Root Trailing Edge Cracks • Corrective action program - 2002M52P09 / P11 blade introduced in 1999 - Endurance testing demonstrated 3X improvement vs. P04/P05 - 2002M52P04/P05 blade retirement program at next shop visit - CFM56-7B S/B 72-115 revised June 2001 - Category 4 - CFM56-5B/P S/B 72-370 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 preground, balanced blades - December 2001 Fleet Highlites article introduced procedure CFM56-5C China All Operators Meeting 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 10 • Further durability improvements - 1957M10P01 HPT blade - 10,000 accelerated development engine cycles…. no visible cracks. • Production introduction - CFM56-5B/P - (SAC) 575-346 through -358, -360 and up - (DAC) 575-907 and up -7B - CFM56-7B - (SAC) 888-767, -772, -773, -776, -777, 779, -780 through -793, -796 and up - (SAC) 889-795 and up - (DAC) 876-757 and up • HPT blade kit PN 737L325G03 available April 2002 - Kit contains a set of 80 HPT blades, PN 1957M10P01 that have been pre-ground, balanced and numbered M10P01 Factory Testing Demonstrating Further Improvement in Trail Edge Crack Capability HPT Blade Root Trailing Edge Cracks CFM56-5C China All Operators Meeting 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 11 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 CFM56 3D Aero HPT Blade Shank Separation CFM56-5C China All Operators Meeting 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 13 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 CFM56-5C China All Operators Meeting 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 14 • Only shank separation event to date - Over 3300 engines in -5B/P and -7B fleets - Over 10 million cycles 3D Aero Fleet Histogram 0 50 100 150 200 250 300 350 400 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 7500 8000 8500 9000 9500 10000 10500 11000 11500 12000 Part Cycles Since New Number of Engines CFM56-5B CFM56-7 Event HPT Blade Shank Cracking CFM56-5C China All Operators Meeting 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 15 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 CFM56-5C China All Operators Meeting 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 16 Cross Sectional View of Cooling Cavity Local stress riser at transition 0.420 inch (10,7 mm) HPT Blade Shank Cracking CFM56-5C China All Operators Meeting 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 17 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 CFM56-5C China All Operators Meeting 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 18 • Ten engines removed to sample high-cycle blades - Five CFM56-5B/P (up to 7599 CSN) - Five 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 4285 blades inspected - Sampling engines plus routine shop visits - Visual, eddy current, and metallurgical - 269 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 • Blade Design Changes • Blade Rework • Test Program • Field Recommendations HPT Blade Shank Cracking CFM56-5C China All Operators Meeting 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 20 • Interim action taken: - PN 2002M52P14 blade released - CFM56-5B/P SB 72-0400 - ESN Intro.: 575-256 through -260, -262 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 2nd quarter 2002 Blade Design Changes HPT Blade Shank Cracking CFM56-5C China All Operators Meeting 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 21 Blade Rework • Strip process developed for blade shank 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 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 - Target completion 4Q02 HPT Blade Shank Cracking CFM56-5C China All Operators Meeting 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 22 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 CFM56-5BP/-7 HPT Blade Airfoil Separation CFM56-5C China All Operators Meeting 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 24 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 CFM56-5C China All Operators Meeting 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 25 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 Telemetry testing to investigate HPT Blade Airfoil Separations CFM56-5C China All Operators Meeting 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 26 • 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 Unusual Blade Vibratory Response Measured in Telemetry Testing HPT Blade Airfoil Separations CFM56-5C China All Operators Meeting 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 27 • CFM working to understand single blade response - Telemetry instrumentation revalidated post-test - Analysis being conducted to support single blade response - Detailed characterization of blade (frequencies, geometry) - Second build of telemetry engine likely Investigation Status Time Lag HPT Blade Airfoil Separations CFM56-5BP/-7 HPT Blade Trailing Edge Separation CFM56-5C China All Operators Meeting 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 29 Background 5 events of HPT blades with missing trailing edge material • Missing HPT blade material observed on factory endurance engine 779-193/4a • 4 events reported from the field ESN Blade PN PTSN PCSN 779311 2002M52P05 9025 3968 779318 2002M52P05 7942 5002 874494 2002M52P09 9403 3249 875240 2002M52P05 10459 3772 1 finding of HPT blades with crack indications • PCA ESN 875201, TSN/CSN 12845/4802 - Found at piece part inspection, 5 blades with crack indications CFM56-5B/P & -7B HPT Blade TE Liberations CFM56-5C China All Operators Meeting 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 30 PCSN Fleet Histogram – TE Liberation Events 0 50 100 150 200 250 300 350 400 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 7500 8000 8500 9000 9500 10000 10500 11000 11500 Part Cycles Since New Number of Engines CFM56-5B CFM56-7 779-311 (27K) (9025/3968) 875-240 (27K) (10459/3772) 779-318 (27K) (7942/5002) 874-494 (26K) (9403/3249) CFM56-5B/P & -7B HPT Blade TE Liberations Factory Test 779-193/4A (4215 cyc) PCA 875-201 (27k) 3 blades cracked (12845/4802 CFM56-5C China All Operators Meeting 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 31 Investigation Status • Metallurgical investigation determined that an LCF crack initiated on the inside wall of passage 8 of the airfoil - Crack propagates to liberate blade trailing edge material - Team working to confirm crack initiation is due to a high stress concentration that results from a sharp corner machined into the blade core - Tight radius at transition of T/E slot rib to cavity - Because of flow dynamics of core material its necessary to “flash” the die in order to fill the trailing edge slots - The subsequent finish machining operation at core level can remove any core die generated radius - Tight radius results in higher stress concentration - Additional field return blades in metallography to confirm root cause Current Field Recommendation • No change to current maintenance recommendations - All occurrences found during routine borescope inspection - No reports of engine vibration increases - Only minor down stream damage reported CFM56-5B/P & -7B HPT Blade TE Liberations CFM56-5C China All Operators Meeting 2002 CFM Proprietary Data Unauthorized Disclosure Prohibited 32 • Root Trail Edge Cracking - Limited to P04/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 10 million cycles 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 being confirmed - CFM working to identify affected blade part number population - CFM will continue to update at WTT and Focus Team calls - No change to current maintenance recommendations HPT Blade Summary作者: 979199501 时间: 2011-4-12 00:19:45 标题: 回复 1# 航空 的帖子
CFM56-7B TRAINING MANUAL ENGINE FAN TRIM BALANCE作者: rickyhua 时间: 2011-5-9 22:50:56