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CHROMIUM PLATING REPLACEMENT AT SIKORSKY AIRCRAFT. ROBERT GUILLEMETTE JOHN BARTALOTTA MATERIALS AND PROCESSES ENGINEERING APRIL 26, 2001. OUTLINE. I. Current chrome plating applications II. Past & current efforts with thermal spray coatings
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CHROMIUM PLATING REPLACEMENT AT SIKORSKY AIRCRAFT ROBERT GUILLEMETTE JOHN BARTALOTTA MATERIALS AND PROCESSES ENGINEERING APRIL 26, 2001
OUTLINE • I. Current chrome plating applications • II. Past & current efforts with thermal spray coatings • III. Methodology for qualification of thermal spray coated components
US ARMY US NAVY US MARINES US AIR FORCE
Current Applications for Chromium Plate • Airframe • Drive System • Rotors • Flight Controls
H-60 Main Gearbox Chromium Plate Replacement SEAL SLEEVE, MAIN ROTOR SHAFT
H-60 Tail Gear Box Chromium Plate Replacement OUTPUT GEAR TORQUE WASHER INBOARD RETENTION PLATE SLEEVE INPUT
Flight Controls Chromium Plate Replacement: non-hydraulic and hydraulic components Primary Servos Boost Servos
Steels 4340 (150-280 ksi) 300M (280 ksi) Stainless Steels 17-4 15-5 PH13-8Mo Aluminum 7075-T73 Titanium None Carburized Steels None Base Metals Plated With Chromium
PRIMARY ALTERNATIVES DETONATION GUN SUPER DETONATION GUN PLASMA HVOF
Detonation Gun • Over 35 years experience with detonation gun thermal spray coating • Excellent track record • Specified for difficult, critical applications • Chromium replacement primarily done for improved performance, now environmental driven
Current Super DGun Technology • Several applications on S-92 and RAH-66 Comanche • Implemented reduced weight designs by taking advantage of improved fatigue strength of DGun over chromium electroplate • Comparison testing shows Super DGun has superior fatigue properties to HVOF
HVOF Coating Evaluated at Sikorsky Aircraft • Diamond Jet • Aluminum Silicon • tungsten carbide • JP5000 Tungsten Carbide • Jet Kote tungsten carbide
Thermal Spray Tungsten Carbide Results in Substantial (6x) Life Improvement for H-60 Main Rotor Shaft Detonation Gun Tungsten Carbide reduces fretting fatigue at bearing journals (implemented 1987)
HVOF Aluminum Silicon for Rework of Magnesium Transmission Housings (implemented 1992)
SH-60 DAMPER • IMPROVEMENTS • ZERO LEAKAGE FROM THE STATIC SEAL AREA HAS BEEN ACHIEVED SINCE THE INCORPORATION OF THE TUNGSTEN CARBIDE COATING. • THE TRIBALOY AND TUNGSTEN CARBIDE COATINGS ARE SHOWING A GREAT IMPROVEMENT OVER THE CHROME AT 750 HOURS. • ISSUES • DAMPER BENCH TEST STOPPED AT ~750 HOURS DUE TO LEAKAGE FROM DYNAMIC END OF DAMPER AND FAILURE OF THE NON-METALLIC BUSHING. • AWAITING STRONGER NON-METALLIC BUSHING FROM SUPPLIER. THE BUSHINGS ARE EXPECTED TO BE DELIVERED LATE MARCH 2001.
SH-60B Tail Landing Gear Piston, Cleveland Pneumatic PN 2012C4, Base Metal: 300M Steel, Coated with SDG2057 tungsten carbide chromium
Coating adhesion Tensile Fatigue (HCF) Fatigue (LCF) Cyclic stress/strain Metallurgical Wear test (bench scale) Drop test (full scale) Corrosion open section crevice testing First article destructive evaluation/validation NAVAIR review Lead-the-fleet testing Qualification Test matrix for Navy H-60 Tail Gear Piston
Adhesion (coupon) Metallurgical (coupon & full scale) hardness porosity/uniformity heat/mechanical effect on substrate Fatigue (coupon) Fatigue after exposure to salt fog (coupon) Wear test (data from Garlock) Corrosion testing (full scale) Army AMCOM review Lead-the-fleet testing Qualification Test Matrix for UH-60 tail landing gear fork
Guidelines for qualification of components with chrome plate replacement • Parts have frozen process planning. Change of supplier may require full scale testing • Difficulty exist with across-the-board substitution by similarity qualification • Lead-the-fleet (actual service operations) often needed as part of qualification • Flight Safety parts to be addressed by Flight Safety Change Board
CONCLUSION • Chromium replacement for multi-service helicopters is a continuing effort at Sikorsky Aircraft • Criteria for qualification is a major challenge