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Keith Legg 847-680-9420
Test Status Overview
HCAT Program ReviewNASA, Florida
Dec 13,14, 2000
Keith Legg 847-680-9420
Rationale
A lot of data has been generated in HCAT/CHCAT program in the past 3 or 4 months
Aim is to show overall status - where we are in testing and what we have learned overall Put current data in a logical order Address what we are doing to resolve some testing
issues Suggest some “compartments” for existing and new
data
Keith Legg 847-680-9420
Overview
Aircraft use of HVOF coatings
Why are we doing this? - commercial flight tests
Overall status of JTP tests JTP - Corrosion, wear,
fatigue, embrittlement, impact
Ancillary - Process specs, producibility, additional corrosion, additional fatigue, failure mechanisms
Conditions seen by real parts
Summary of findings to date
What does all this mean for actual usage?
Where does it work just fine?
Where do we need to worry?
Keith Legg 847-680-9420
Flight testing - Why are we doing this?
Flight testing (Boeing, Delta, Lufthansa etc.) shows acceptable performance with no serious problems Wear performance much better than chrome
no gouges, striations, flaking, etc. commonly seen in Cr better seal life if Ra~4” (rapid seal damage if rough) some FPI crack pattern indications on Lufthansa aft inner
cylinders (Barkhausen showed no crack penetration to substrate), nothing requiring removal from service
Typical chrome damage - axle
Keith Legg 847-680-9420
Production use of HVOF WC-Co and WC-CoCr coatings
Keith Legg 847-680-9420
Production use of HVOF WC-Co and WC-CoCr coatings (cont.)
Qualified for landing gear repair <0.010”
Keith Legg 847-680-9420
Production use of HVOF landing gear coatings - Messier-Dowty
Note production use on high performance aircraft
Program-p/n Part name Type of coating Area Remarks
F/A-18 E/F 74A430702 74A430616
Piston head assy Retract Actuator NLG Cover assy Gear/manifold
Diamalloy 1004 (Al bronze) Applied per AMS2447 Tribaloy T400
6.612 OD 8.974 ID
Production part Production part
F/A-18 C/D 74A410603 Head, Piston Shock Absorber
MLGF-18 E/F
Diamalloy 1004 (Al bronze) Applied per AMS2447
OD R&O DRED
Hawker 4000 34520-1 Lock link outboard forward
door mechanism NLG WC-Co per DCMP 210 (AMS2447-7)
Flat stops Production part
REO 450626-01
Tube Restrictor Support AMS 2447-4 Ni95-Al5
2.623/2.621 OD R&O
74A410509 Axle of the polygon AMS 2447-9 2.931/3.374 polygon
In progress
Cl601RJ 17114-1
Shock strut piston MLG WC-Co-Cr per DCMP 213 (AMS 2447-9)
4.614 OD Under evaluation in service by Air Canada, NIEO
17207-1
Shock strut pin MLG
WC-Co-Cr per DCMP 213 (AMS 2447-9)
1.498 OD Under evaluation in service by Air Canada, NIEO
A340 CLG 37173-101 37174-101 15173-101 15174-101
Sleeve thrust shock strut Tribaloy T400 DCMP 203 (AMS2447-2)
2.348 ID Production part
BD 100 40672 Pin, Piston Tube
NLG WC-Co-Cr per DCMP 213 (AMS 2447-9)
0.866 OD Production part
Keith Legg 847-680-9420
Data summary:Landing Gear JTP - Coupon test data
Data Item Test 25 50 75 100 Pass Fail NotesCorrosion
C-HCAT salt fog ASTM B-117 x Standard flatUS-HCAT salt fog B117 ??? Modified sample. Retesting
US-HCAT cyclic salt fog GM 9540P/B ??? Modified sample. RetestingH Embrittlement
US-HCAT Deposition ASTM F-519 x No embrittlement by HVOFUS-HCAT H Evolution ASTM F-519 - - No acceptance criteria
US-HCAT Environmental Emb. ASTM F-519Fatigue WC-Co (Hourglass)
US-HCAT in air 0.003" ASTM E-466 x R=-1, 0.1US-HCAT in air 0.010" ASTM E-466 x R=-1, 0.1
US-HCAT corrosion ASTM E-466 x R=-1, 0.1Fatigue WC-CoCr (Smooth bar)
C-HCAT air 0.003" thick ASTM E-466 x R=-1. Delamination above 180 ksi loadC-HCAT air 0.010" thick ASTM E-466 ??? R=-1. Delamination above 125 ksi load
C-HCAT corrosion ASTM E-466 ??? R=-1. Rapid corrosion initial testsC-HCAT low temp. ASTM E-466
ImpactDropped ball Data being obtained
Gravelometry ASTM D-3170 x Equivalent or better than CrWear
Fretting GEAE Data complete - being analyzedOsc. piston/bushing Hydraulic simul. Data complete - being analyzed
Completeness
Keith Legg 847-680-9420
Data summary:Propeller Hub JTP - Coupon test data
Data Item Test 25 50 75 100 Pass Fail NotesCorrosion
WC-Co, WC-CoCr, T800, Ni plate ASTM B-117 Standard 4"x6" flat panelFatigue (Hourglass)
WC-Co, T800, Cr ASTM E-466 HSD hourglass, R=0.1WC-Co, T800 ASTM E-466 HSD notched hourglass, R=0.1
WearLarge stroke and dither HSD HSD wear plates
Toxicity leachingWC-CoCr, T400, T800 waste EPA 1311 Acetic acid leach
Completeness
Keith Legg 847-680-9420
Corrosion
C-HCAT B117 JTP work complete
HVOF performed significantly better than chrome - Pass
US-HCAT B117 Initial test results reported in
Ottawa, Aug 00 HVOF coatings worse than
Cr - Fail Appears to be a testing issue
Outstanding issues - resolution of US-HCAT results Retesting under way
Different sealing - Boeing Cd method 2 different geometries (Flats and cylinders) 2 different deposition conditions (Southwest Aero, Hitemco) 2 different cabinets
Keith Legg 847-680-9420
Embrittlement
Tests partially complete Sequence 1 - HVOF does not cause embrittlement -
Pass Sequence 2 - Not yet complete
H2 can diffuse through HVOF coating May need longer bake
Sequence 3 begun - no data yet Outstanding issues
Environmental embrittlement measurements in process
Coating may lower Kt - calculations and tests under way at Heroux
Keith Legg 847-680-9420
Fatigue - WC-Co
WC-Co US-HCAT testing
complete All WC-Co air fatigue
data equal to or better than Cr - Pass
All WC-Co corrosion-fatigue data equal to or better than Cr - Pass
Delamination from some specimens at high cycles
WC-CoCr WC-CoCr 0.003”
delamination at high load - Pass below 180 ksi, Fail above 180 ksi
WC-CoCr 0.010” delamination at high load - Pass below 125 ksi, Fail above 125 ksi
WC-CoCr corrosion-fatigue - Fail??
Not a structural issue, but a functional issue (Messier-Dowty) Outstanding issues
Results of WC-CoCr fatigue testing being addressed under Ancillary Testing
Keith Legg 847-680-9420
Wear
Fretting and sliding (hydraulic) Data evaluation largely complete HVOF better than or equal to Cr
Rig and flight tests all show better wear performance Less striation, wear, roughening (Delta, Greene
Tweed) Less wear and leakage of seals (Greene, Tweed)
Keith Legg 847-680-9420
Impact
Drop ball testing Under way
Gravelometry (Boeing) Completed - HVOF as good as or better than Cr - Pass
Keith Legg 847-680-9420
Data summary:Landing Gear JTP - Rig and flight testing
Data Item Test 25 50 75 100 Pass Fail NotesRig tests
Boeing F-18 LG pins Full scale x HVOF pins included in rig testHydraulic testing Hydraulic x Greene, Tweed - long stroke and dithering spectrum
M-D F-18 E/F NLG fat. Fatigue Without catapult loadsM-D F-18 E/F drag brace fat. Endurance
BFG Dash-8/400 MLG Full scale Rig complete, awaiting all test item partsBFG NLG steering act. Full scale
BFG simulated piston fat. Full scale sim Full scale piston fatigue simulationBoeing C-17 forward MLG Full scale Durability - proposed. Out for coordination
Repair scheme rig (Heroux)CF-18 A/B NLG shock strut Full scale HVOF restrictor tube - compression, cyclic loadingCF-18 A/B MLG crank assy Full scale Torsion loads equivalent to landing loads
CC-130 steering collar Full scale Endurance lifeFlight tests
Delta B737, 757, 767 LG x Internal Delta, not HCAT-sponsoredM-D CF-18 polygon repair x Internal Messier-Dowty, not HCAT-sponsored
NADEP-JAX P-3C-HCAT DND C-130 C-HCAT testing
KC-135, MLG, NLG piston Air Force - military typical worst caseF-16 NLG Air Force - high performance worst case
Completeness
Keith Legg 847-680-9420
Data summary:Propeller Hub JTP Rig and flight testing
Data Item Test 25 50 75 100 Pass Fail NotesRig tests
54H60 low pitch stop lever sleeve Piston stroke WC-Co and T800Flight tests
P-3 propeller 275 flight hrs Tail shaft hub and sleeve lever
Completeness
Keith Legg 847-680-9420
Hydraulic testing - Greene, Tweed
PTFE (Enercap) much better performance with WC
low leakage low rod wear
Elastomer rapidly damaged
not a problem with long stroke utility actuators and landing gear at 4 Ra
5
15 25 35 45
WC-Co, ACTTribaloy, ACT
Chrome, ACT
WC-Co-Cr, EnercapWC-Co, Enercap
Tribaloy, Enercap
Chrome, Enercap
0
500
1000
1500
2000
2500
Lea
kage
(g
ram
s)
Cycles (millions) 4-9 ” Ra
Keith Legg 847-680-9420
Landing gear rig tests
Boeing F/A-18 E/F landing gear pins HVOF coatings “passed” full scale rig fatigue test
darkened, but no wear damage, passed MPI
Outstanding - Additional full scale tests to be done by C-HCAT Messier-Dowty F-18 E/F NLG fatigue Messier-Dowty F-18 E/F drag brace fatigue
including catapult loads BFG Dash-8/400 MLG BFG NLG steering actuator BFG simulated piston fatigue
Keith Legg 847-680-9420
Flight tests
Delta B737, 757, 767 nose and main landing gear Inner cylinders, axles, axle sleeves
Passed - WC-CoCr qualified for O&R
Boeing 767-400 HVOF WC-CoCr flight qualified and used in production
Canadian F-18 MLG Messier-Dowty polygon repair
WC-CoCr Repair scheme approved
Outstanding - NADEP-JAX P3, DND C-130 testing
Keith Legg 847-680-9420
Data summary -Ancillary tests
Data Item Test 25 50 75 100 Pass Fail NotesProcess parameters
US-HCAT WC-Co DOE - -C-HCAT NRC WC-CoCr DOE - -
Commercial - SWA, Hitemco - - Boeing QPL processesGrinding/finishing
NADEP-JAX - - Low stress grind used on samplesDelta Airlines - - Used on flight test landing gear
HerouxStripping
NADEP-CP, S'west Aero x WC-Co and WC-CoCr strip w/RochelleCTC water jet x Incomplete stripping
HerouxR&O Fluid compatibility
HerouxNDI
HerouxDelta, Boeing flight tests - - FPI, Barkhausen good; MPI poor
CorrosionBeach exposure x Flat samples - generic tests
Salt fog B117 x Flat samples - generic testsCyclic salt fog GM 9540P/B x Flat samples - generic tests
US-HCAT comparison tests B117 New seal; flat, round, var. vendors, var. cabinetsFatigue (Smooth bar)
US/C-HCAT WC-CoCr air ASTM E-466Fracture mechanisms
C-HCAT NRC/Orenda - -Specifications
AMS specs - - Powder, grinding, coating
Completeness
Keith Legg 847-680-9420
Process parameters
WC-Co optimized by Jerry Schell by DOE methods OO-ALC, Hitemco - JP 5000, DJ Process designed for 8-12 Almen compressive stress
WC-CoCr optimized by Jean-Gabriel Legoux, NRC by DOE methods DJ-gun at NRC and VacAero Process designed for 8-12 Almen compressive stress Coating parameters different from QPL conditions
used by Southwest Aero
Keith Legg 847-680-9420
Grinding and finishing
Overall finding - for seals need 4” or less Ra Use fine grind or superfinish (specify other parameters?)
Low stress grinding developed by Jon Devereaux at NADEP-JAX used on all US-HCAT samples
Surface measurement and superfinishing developed for landing gear by Jay Randolph at Delta
Testing carried out by John Falkowski (Boeing) and Jim Nuse (Southwest Aeroservice) - AESF paper
Additional testing under way Boeing, SW Aero, Sulzer Metco, Engelhard, Praxair, Green
Tweed, Supfina, Delta
Keith Legg 847-680-9420
Stripping
Water jet does not work very well Rochelle salt works well for WC-Co and WC-
CoCr SW Aero, Sulzer Metco NADEP-Cherry Point, NTS
Testing at Praxair and others shows no embrittlement with strippers
No good method for T400 yet Outstanding - need good chemical strip for
Tribaloy
Keith Legg 847-680-9420
Fluid compatibility
Under way shortly at Heroux Will include evaluations of hydrogen
embrittlement due to fluids
Keith Legg 847-680-9420
NDI
FPI best method so far Delta, Boeing
MPI not effective Boeing has used Barkhausen with some success Heroux testing begun Outstanding - how detect cracks in substrate
without removing coating?
Keith Legg 847-680-9420
Corrosion
All HCAT generic, C-HCAT, Lufthansa data on flats shows HVOF having better performance than Cr US-HCAT Landing gear JTP data on rods showed worse
than Cr - Fail Repeating with better edge seal - comparing sample
shapes, deposition conditions, test locations
Outstanding - Resolution of poor US-HCAT test performance (under way)
Keith Legg 847-680-9420
Fatigue and fracture
Fatigue of WC-CoCr - the picture folks took back from Ottawa meeting
Keith Legg 847-680-9420
Fatigue and fracture
Findings of cracking by AFRL (Bob Ware) Careful analysis done at NRC (Jason Dyer, Peter Au)
WC-CoCr fails, cracks and delaminates under high compressive load (R=-1)
0.003” coating, failure at 180 ksi and above 0.010” coating, failure at 125 ksi and above (note that thicker
coating carries more load) cracks grow down from coating surface and often run parallel
to interface (similar mechanism to that designed into composites)
cracks do not appear to propagate from coating into substrate Surfaces of WC-CoCr fatigue specimens from Southwest
Aeroservice also show crack pattern and some spalling at failure and runout
This shows there may be operational limits of WC-CoCr
Keith Legg 847-680-9420
Where should we be testing?What are the real-world requirements?
What are the functional limits of WC-CoCr and WC-Co?
Questions:
Keith Legg 847-680-9420
Bend test of Praxair WC-CoCr. Reported by Jay Randolph, Delta
Airlines, July 1998
Fatigue and cracking - historical
Fracture data - John Quets, Shane Arthur WC-Co initially designed using bend test cracking data WC-CoCr designed to have better corrosion performance,
but lower fracture strength So, WC composite coatings balance hardness and wear
resistance against brittleness (fracture strength)
1998 - Crack-like indications found by FPI on aft side of WC-CoCr-coated Lufthansa landing gear. Barkhausen analysis by Boeing showed no crack propagation into steel. Returned to service - no reported problems.
Keith Legg 847-680-9420
Landing gear design and fatigue testing
Designers do not design to specimen test data Coupons provide stress engineers the data to start
analyzing for customer and air-worthiness justification
Difficult to translate from load on full scale item to stress on test coupon
Qualification always depends on full-scale item fatigue testing under spectrum loading to 2 or 4 lifetimes
Bulk of public domain data for AerMet 100 was run at 150 ksi or less (Roger Eybel) a few points were run higher for interest sake
Keith Legg 847-680-9420
Fatigue - Loads on Landing Gear
Name Company Maximum stress (kpsi)
R ratio Sample type Notes
Gary Erickson Boeing Commercial 170 0.1 Large hourglass Vendor qual testRoque Panza-Giosa BFG 180 -1 Al alloys 20ksiCraig Edwards GA/Air Force 180 -1 Actual LG 180kpsi is once-in-a-lifetime
event. 135 normal useRoger Eybel Messier Dowty 150 A100 test
specimensBulk of public domain data - some at higher load for interest only
Dave Weldon Messier Dowty 211 Full scale gear Drag Brace Trunnion Pin Test - max bending stress
Michael Kane NAVAIR 180 Test specimens Limit Ultimate (P3, E6, V22)Michael Kane NAVAIR 240 Test specimens Design Ultimate (high
performance)Nihad Ben-Salah Heroux 195 0.1, -1 Test specimens 4340 (90% of yield)
207 0.1, -1 Test specimens 300M (90% yield)225 0.1, -1 Test specimens A100 (90% of yield)
Keith Legg 847-680-9420
Fatigue - Loads on Landing Gear
Makes no sense to test coatings above levels used in full rig tests
Looks as though we have the following maximum needs: Commercial 170 ksi, R=0.1 Military, typical 180 ksi, R=-1 Military, high performance 240 ksi, R=-1
Questions: At what loads/cycles were F-18 landing gear qualified? Do you really go to yield thousands of times?
Keith Legg 847-680-9420
Summary of major ongoing work
Corrosion Additional tests planned
samples made
Fatigue C-HCAT testing 0.003”
WC-CoCr below 180 ksi Rethinking tests for
0.010” WC-CoCr Comparative testing with
SW Aero WC-CoCr and WC-Co
Embrittlement Environmental embritt.
Ball impact - in progress
Producibility testing Heroux - grinding,
stripping, NDI, fluids, etc. Rig testing
BFG, Messier-Dowty Flight testing
NADEP-JAX P3 DND CC-130
Keith Legg 847-680-9420
Remaining issues being resolved
US-HCAT corrosion testing to be redone obviously testing problem
Fatigue testing Not a structural issue that will cause failure, but a
functional issue that will impose limits Clearly define fatigue limits and requirements
Understand strain-to-failure, fatigue, residual stress relationships
Definition of load/thickness limits for WC-Co as done for WC-CoCr
WC-CoCr with hourglass specimens to define S/N curve comparable with WC-Co per JTP?
Keith Legg 847-680-9420
Where does qualification look good?
Commercial no brainer - in production
Military - general likely to work with WC-Co may be near edge of
envelope for WC-CoCr High performance military
(primarily fighters) need to define operational
loads carefully to match qual of existing gear
may need lower hardness, higher toughness material
Full article tests - rig, flight
Keith Legg 847-680-9420
Remaining issues
US-HCAT corrosion testing to be redone obviously testing problem
Fatigue testing of WC-CoCr with hourglass specimens define S/N curve comparable with WC-Co per JTP
Definition of load/thickness limits for WC-Co as done for WC-CoCr