Tuesday PM - Metcut

Tuesday PM EROSION TESTING
GE Aircraft Engines

Erosion Testing
GEAE - E50TF121
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Metcut
training manual
Information
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GE Aircraft Engines
ASTM -G76
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Erosion
Testing
GE Aircraft Engines
E50TF121 - This specification describes a method for determining the room
temperature erosion resistance of coatings.

Erosion Testing
• Class A: Thickness loss
• Class B: Weight loss
• Class C: Thermal Barrier Coating
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GE Aircraft Engines
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Erosion Testing
Coatings
• B50TF232/F50TF75
• B50TF222/Dwg. note
• B50TF119/B50TF64 and
B50TF161/B50TF64
• B50TF281/F50TF79 and
B50TF269/F50TF80
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Applications
GE Aircraft Engines
• F404 compressor casing
• CF6 booster case
• F101/F110 compressor
liners
• CFM56 compressor blades
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Flow Sheet Erosion Tester
3. Press regulator CA
Norgen type 2 Ax4
with 6” face 0 to 100
psig Ashcroft gauge
1. Shut off valve
2. Shradder filter
No. 3534-1000
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6. Universal timer
Model N 171
Dimco Gray Co.
Dayton, Ohio
Air line 4. Solenoid valve
ASCO Cat No.
8211D1
Port A blast gun
Linberg Products Co.
1.75
8. Vibrator Metco
PV 31 Vibrator Ass’y
with transformer
7. Snap-tite quick disconnect
H-series 1/4” size
B.W. Rogers Co.
Woodlawn, Hio
5. Flow meter precision bore flowrator
Tune No. FP 3/4 27G 10/80
Beaded tube
100% = 1625 SCFH
Gas specific gravity of 1.00 at
75 psiG and 70 o F
GE Aircraft Engines
4013240-535 P-2
4013240-535 P-1
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Erosion Testing
The Erosion specimen holder shall be in accordance with GE drawing 4013240-525
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GE Aircraft Engines
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Erosion Gun
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20° Angle
GE Aircraft Engines
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Erosion Testing
B
D
C
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A
E
F G
Critical
Dimension
Hopper
Gun
Critical
4” +/- .060
I
Dimensions Measurements
A 4.50-5.0”
B 12.0” +/- .50”
C 15o +/- 1o D .50”
⇒ E Dia. .25” +/- .010”
⇒ F Air Jet to Nozzle .284” +/- .010”
G 3.75” +/- .30”
⇒ H Dia. .094”
⇒ I .186” +/- .002”
⇒ Denotes critical dimensions
Sample
Dia.
GE Aircraft Engines
Nozzle ID
Nozzle Mfgr. __Abrasive Product___
Gun Mfgr. ___ Port-a-Blast____
Hopper Vibrator X Yes __ No
Air Pressure ____25-35 psi____
Flow rate (air) ____________________
Flow rate (Al 2 0 3 ) ___________ gm/Min
Abrasive Media Mfgr. _____ SS White____
Vibrator Pressure ____12-18 psi____
Vacuum rate _________________
Time ____90-110 sec_____ avg________
Abrasive Screen Before Use X Yes __ No
Hopper
Gun
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Erosion Testing
.500 O .191
.185
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O thru
3.75 +/- .30”
Erosion nozzle
Material: Tungsten Carbide
.550 +/- .020”
Brass ferrule
GE Aircraft Engines
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Erosion Testing
Powder Specifications
• Material: Aluminum Oxide
• Average particle size: 50 Microns
• Appearance: white powder
• Typical chemical composition by weight
-Al2O3 (by difference) 97.02%
-SiO2 - total (free Silica - 0.50% (less than 0.5%
none detected) combined balance)
-Fe2O3 Maximum 0.10%
-Na2O 0.33%
-CaO Maximum 0.10%
-MgO Less than 0.01%
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GE Aircraft Engines
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Erosion Testing - General Requirements
• Coupon size - 1”x2”x.050 - .185”
• Surface preparation - #60 grit or finer paper. Remove
approximately .005” material
• Calibrate apparatus using Lexan samples (1”x2”x.125”) E#
6.0 +/- .5 sec./mil.
• .250” ball tip micrometer (thickness loss)
• Scale requires ability to read weight to nearest thousandth
of a gram (weight loss)
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GE Aircraft Engines
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Erosion Testing - Thickness Loss
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Top view
Side view
GE Aircraft Engines
1/4” dia ball
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Erosion Testing - Thickness Loss
• Before test measure the panel thickness.
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GE Aircraft Engines
• After the test - the deepest point of erosion is measured.
Δ between the thickness is recorded.
• E# = Time (in sec.) to spray the Aluminum Oxide
Depth of erosion (in mils)
• E (normalized) = 6 (sec/mil) X E# (sec/mil)
E# average of Lexan standard
Record to the nearest Hundredths
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Erosion Testing - Weight Loss
• Lexan calibration range - 0.090-0.130 grams
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GE Aircraft Engines
•E w = Weight loss of Lexan (Δg) in micrograms
Weight of Abrasive Powder used (600 ± 10g)
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Erosion Test Report
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GE Aircraft Engines
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Why Erosion Testing?
Erosion testing, as indicated in the Thermal Spray Section, is a very specialized test for a few
specialized coatings.
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GE Aircraft Engines
Erosion occurs on jet engine components when fine particles become airborne and are ingested
through the flow path of the jet engine. These airborne particles are usually picked-up during the
landings and take-offs of the airplane. The engine in-takes act like a large vacuum cleaner, inhaling
dirt and sand particles on the runway.
In developing coatings to combat erosion, the Erosion Test was created to help characterize and
evaluate coatings being used in erosion applications. Some of these applications are abradable
coatings in the fan/compressor section, carbide coatings on the rotor blade tips, and TBC coatings in
the turbine section.
Erosion Testing consists of impinging a coated sample with a known abrasive particle utilizing
compressed air as a propellant. The amount of erosion is measured either by the loss of weight or the
loss of coating thickness. It is important to note that the air and the abrasives particles are run at room
temperature during testing. The air and particles can be heated to evaluated temperatures to study
coating behavior during hot erosion, but GEAE does not require such testing on production coatings
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