FINAL REVIEWLanding Gear JTP Wear Test Analyses

J.D. Schell

GE Aircraft Engines

8-28-2001

2HCATToronto MeetingCrowne Plaza HotelAugust 28-30, 2001

Wear Test Schematics

Guide

Oscillating rod

Load

Testbushing Guide

Rod and Bushing wear test.Fretting wear test.

Unctd Part (BBS): Block/Seal Bushing/SealCoated Part (RS) : Shoe Rod

B lock

O scilla ting M otion

Shoe

L O A D

Bushing

Rod

Test MatrixCoatings vs Metal Bushings

• 4340 steel rods 9”x1”– EHC coated, SWA(MIL-STD-1501C, QQ-C-320B)

– WC-17Co (Diam 2005)

– WC-10Co-4Cr (SM5847)

– HVOF by DJ2600 at Ch Pt

– All ground to 8 Ra (-in)

• Bushings, 64 Ra max– 4340 steel, 260-280 UTS

– AMS 4640, Al Ni Bronze

– Anodized 2024 Al, SWA(MIL-A-8625, Type 3, Class I)

Coatings vs Seals

• Nitrile Rubber Seals– Grooved 4340 bushing

– 7214-FT-160-T from Green Tweed

(MIL-HDBK-695C)

• Karon B liner in Al bronze bushing, 0.015” thick layer– Kamatics Corp.

– Filled phenolic compound

Test Matrix (cont.)

C B A DTest No. DOE Expt. No. 4340 Rod Ctg Bushing Cycles Load, lb.49 A&B L8-01 Chrome 4340 80K 7250 A&B L8-02 Chrome 4340 240K 28851 A&B L8-03 Chrome AMS 4640* 80K 28852 A&B L8-04 Chrome AMS 4640 240K 7253 A&B L8-05 WC-17Co 4340 80K 28854 A&B L8-06 WC-17Co 4340 240K 7255 A&B L8-07 WC-17Co AMS 4640 80K 7256 A&B L8-08 WC-17Co AMS 4640 240K 288

1st L8 Half Replicate (a)57 A&B L8-5a WC-10Co-4Cr 4340 80K 28858 A&B L8-6a WC-10Co-4Cr 4340 240K 7259 A&B L8-7a WC-10Co-4Cr AMS 4640 80K 7260 A&B L8-8a WC-10Co-4Cr AMS 4640 240K 288

2nd L8 Half Replicate (b)61 A&B L8-3b Chrome Anodized Al 80K 28862 A&B L8-4b Chrome Anodized Al 240K 7263 A&B L8-7b WC-17Co Anodized Al 80K 7264 A&B L8-8b WC-17Co Anodized Al 240K 288

L8 MATRIX - Metal Bushings

Design Factors

Design factors held constant Test type: Rod/Bushing Coating Finish: 8 Ra Hydraulic Lube: Partial - 1 hr. drip for 4340/Anodize Al/AMS 4640 - 1 hr. pressurized lube for nitrile seal - Dry for KAron B Stroke: 0.5” (1/2 cycle distance) Frequency: 90 cpm Temperature: 75 FVariable design factors Rod coating Bushing type Cycles Normal load

Test Matrix (cont.)C B A D

Test No. DOE Expt. No. 4340 Rod Ctg Bushing Cycles Load, lb.

3rd L8 Half Replicate (c)65 A&B L8-3b Chrome Nitrile seal 80K 28866 A&B L8-4b Chrome Nitrile seal 240K 7267 A&B L8-7b WC-17Co Nitrile seal 80K 7268 A&B L8-8b WC-17Co Nitrile seal 240K 288

4th L8 Half Replicate (d)69 A&B L8-3d Chrome KAron B seal 80K 28870 A&B L8-4d Chrome KAron B seal 240K 7271 A&B L8-7b WC-17Co KAron B seal 80K 7272 A&B L8-8b WC-17Co KAron B seal 240K 288

B C5th L8 Half Replicate (e) 4340 Rod Ctg Bushing

73 A&B L8-1e Chrome KAron B seal 80K 7274 A&B L8-2e Chrome KAron B seal 240K 28875 A&B L8-3e WC-10Co-4Cr KAron B seal 80K 28876 A&B L8-4e WC-10Co-4Cr KAron B seal 240K 7277 A&B L8-5e Chrome AMS 4640 80K 28878 A&B L8-6e Chrome AMS 4640 240K 72

B C6th L8 Half Replicate (f) 4340 Rod Ctg Bushing

79 A&B L8-1f Chrome Nitrile seal 80K 7280 A&B L8-2f Chrome Nitrile seal 240K 28881 A&B L8-3f WC-10Co-4Cr Nitrile seal 80K 28882 A&B L8-4f WC-10Co-4Cr Nitrile seal 240K 72

Design Factors

L8 MATRIX - Seal Bushings

Wear Measurement AccuracyWeights 51 53 56 57 28 92 93 941st meas. 884.2475 883.5675 883.7347 882.9758 873.7553 874.265 875.2033 875.45052nd meas. 884.2478 883.5673 883.7348 882.9759 873.7559 874.2651 875.2032 875.45063rd meas. 884.2477 883.5676 883.7349 882.9763 873.7557 874.2649 875.203 875.45034th meas. 884.2476 883.5675 883.7346 882.9760 873.7556 874.265 875.203 875.45025th meas. 884.2476 883.5679 883.7350 882.9764 873.7555 874.2644 875.2028 875.45016th meas. 884.2478 883.5679 883.7349 882.9762 873.7553 874.2643 875.2033 875.4499

AVG 884.2477 883.5676 883.7348 882.9761 873.7556 874.2648 875.2031 875.4503St Dev 0.000121305 0.000240 0.000147 0.000237 0.000234 0.000343 0.0002 0.000259

max 884.2478 883.5679 883.7350 882.9764 873.7559 874.2651 875.2033 875.4506min 884.2475 883.5673 883.7346 882.9758 873.7553 874.2643 875.2028 875.4499Range 0.0003 0.0006 0.0004 0.0006 0.0006 0.0008 0.0005 0.0007 wgts error range

Densities Max Vol error

13.6 0.00002 0.00004 0.00003 0.00004 0.00004 0.00006 0.00004 0.00005 0.00006 carbides

7.2 0.00004 0.00008 0.00006 0.00008 0.00008 0.00011 0.00007 0.00010 0.00011 metals & EHC

1.27 0.00024 0.00047 0.00031 0.00047 0.00047 0.00063 0.00039 0.00055 0.00063 seals & anodize

Wear volumes corresponding to delta weight ranges

Rod Number

Wear Volumes from delta weight

Vol = Wgt/density

Densities of test matls (gm/cc) EHC = 7.2 4340 =7.83 nitrile=1.27 WC-17Co=12.2 AlNiBR=7.12 Karon B=1.51WC-Co,Cr=13.6 anodized Al = 3.16 (up to ~3.6 max)

Wear Measurement (cont.)• Cleanliness of specimens was an on-going

source of error– isolated early occasions where heavy oil and

grit in threaded and center point vee were found gave up to 0.15 gm error in weight

– improved, but still easily up to 0.01 gm error when missed

Due to cleanliness issues, a second method of wear assessment based on visual ratings was developed and used in addition to wgts

Statistical Model Wear Results for 4340 Bushings

Load, lbs Cr Rod WC-Co WC-Co-Cr 4340 vs Cr vs WC-Co vs WC-Co-Cr72 -0.00051 -0.00062 -0.001258 0.00003 -0.00110 0.00013

288 -0.00028 -0.00016 -0.0011934 -0.00112 -0.017008 -0.00483

-0.00035 -0.00066 -0.0005051 -0.00378 0.0038438 2.97E-05-0.00028 -0.00028 -0.0002846 -0.00112 -0.001117 -0.0011175

ROD CTG OPPOSING BUSHING

Coatings' Wear with 4340 Bushings

-0.020

-0.015

-0.010

-0.005

0.000

0.005

0.010

50 100 150 200 250 300Load, lbs.

We

ar

Vo

lum

es

Cr Rod

WC-Co

WC-Co-Cr

4340 vs Cr

vs WC-Co

vs WC-Co-Cr

Max MeasurementError When Poor

Cleaning Occurred

MeasurementPrecision (X3)

Visual Appearance of Coated Rods

• All tested rods visually rated from 1-10

• Initial L12 DOE specimens showed wide range of wear scar appeances. Picked least damaged as a 1 and worst damaged as a 10.

• Selected others as 2, 3, 6, 7, and 8 and adopted these as photostandards for rating rods. All rods laid out and compared side by side with the original rods of the standards (not to photos which follow)

VR 2

VR 3

VR 7

VR10

1 2 3 4 5 6 7 8 9

0

1

2

3

4

5

6

7

8

9

10

Visual Ratin

FIT

S1

Y = 1.01499 + 0.525466X + 3.94E-02X**2

R-Sq = 95.3 %

Regression

95% CI

L8 Baseline Visual vs DOE Model: Quadratic FitChrome and WC-Co

1 2 3 4 5 6 7 8 9

0

1

2

3

4

5

6

7

8

9

10

Visual

FIT

S3

Y = 1.16935 + 0.577381X + 2.40E-02X**2

R-Sq = 83.0 %

Regression

95% CI

RegressionL8 1st Half Rep Actual Visual vs DOE Model; Quadratic

Coatings vs Metal Bushing Summary (Avgs of Orthogonal Arrays)

MaterialPair Rod Bushing Visual

Cr/4340 -0.000375 -0.000348 6.25WC-Co/4340 -0.000578 -0.010386 3.00WC-Co,Cr/4340 -0.002076 -0.010691 2.50

Cr/AlNi Bronze -0.000832 -0.002549 3.25WC-Co/AlNi Bronze -0.000193 -0.007935 4.75WC-Co,Cr/AlNi Bronze -0.002384 -0.006981 4.25

Cr/Al Anodize -0.000769 -0.000069 6.75WC-Co/Al Anodize -0.000238 0.000088 1.25

Volume Wear

= Data believed to be heavily influenced by measurement errors

L8 Baseline DOE Rod & Bushing Wear Volumes

-0.015000

-0.012500

-0.010000

-0.007500

-0.005000

-0.002500

0.000000

0.002500

49A-E

HC/434

0/80

K/72

49B-E

HC/434

0/80

K/72

50A-E

HC/434

0/24

0K/2

88

50B-E

HC/434

0/24

0K/2

88

51A-E

HC/AlN

iBr/8

0K/2

88

51B-E

HC/AlN

iBr/8

0K/2

88

52A-E

HC/AlN

iBr/2

40K/7

2

52B-E

HC/AlN

iBr/2

40K/7

2

53A-W

CCo/434

0/80

K/288

53B-W

CCo/434

0/80

K/288

54A-W

CCo/434

0/24

0K/7

2

54B-W

CCo/434

0/24

0K/7

2

55A-W

CCo/AlN

iBr/8

0K/7

2

55B-W

CCo/AlN

iBr/8

0K/7

2

56A-W

CCo/AlN

iBr/2

40K/2

88

56B-W

CCo/AlN

iBr/2

40K/2

88

Rod Bushing

EHC WC-Co

4340 4340Al Ni Bronze Al Ni Bronze

Statistical Model Wear Results for 4340 Bushings

Load, lbs Cr Rod WC-Co WC-Co-Cr 4340 vs Cr vs WC-Co vs WC-Co-Cr72 -0.00051 -0.00062 -0.001258 0.00003 -0.00110 0.00013

288 -0.00028 -0.00016 -0.0011934 -0.00112 -0.017008 -0.00483

-0.00035 -0.00066 -0.0005051 -0.00378 0.0038438 2.97E-05-0.00028 -0.00028 -0.0002846 -0.00112 -0.001117 -0.0011175

ROD CTG OPPOSING BUSHING

Coatings' Wear with 4340 Bushings

-0.020

-0.015

-0.010

-0.005

0.000

0.005

0.010

50 100 150 200 250 300Load, lbs.

We

ar

Vo

lum

es

Cr Rod

WC-Co

WC-Co-Cr

4340 vs Cr

vs WC-Co

vs WC-Co-Cr

Max MeasurementError When Poor

Cleaning Occurred

MeasurementPrecision (X3)

0.000-0.001-0.002-0.003-0.004-0.005-0.006

0.000

-0.001

-0.002

-0.003

-0.004

-0.005

Rod Wear Vol

FIT

S1

R-Sq = 33.6 %

Y = -1.0E-03 + 0.106701X - 43.8267X**2

95% CI

Regression

RegressionL8 1st Half Rep Actual Rod Wear vs DOE Model; Quadratic

-0.04 -0.03 -0.02 -0.01 0.00

-0.03

-0.02

-0.01

0.00

Bushing Wear

FIT

S2

Y = -2.5E-03 + 0.617078X + 4.00572X**2

R-Sq = 46.1 %

Regression

95% CI

RegressionL8 1st Half Rep Actual Bushing Wear vs DOE Model; Quadratic

Statistical Model Wear Results for NiAl Bronze Bushings

Load, lbs Cr Rod WC-Co WC-Co-Cr NAB vs Cr vs WC-Co vs WC-Co-Cr72 -0.00079 -0.00067 -0.00170 -0.00200 -0.01789 -0.00571

288 -0.00057 -0.00029 -0.00163 -0.00315 -0.01522 -0.01067

-0.00079 -0.00079 -0.00079 -0.00200 -0.00200 -0.00200-0.00072 -0.00042 -0.00057 -0.006963 0.00067 -0.00315

ROD CTG OPPOSING BUSHING

Coatings' Wear with Ni Al Bronze Bushings

-0.020

-0.015

-0.010

-0.005

0.000

0.005

0.010

50 100 150 200 250 300Load, lbs.

Wea

r V

olu

me,

cc

Cr Rod

WC-Co

WC-Co-Cr

NAB vs Cr

vs WC-Co

vs WC-Co-Cr

Fractional Factorial Fit with Chrome & WC-Co Coatings

Estimated Effects and Coefficients for Rod Coating Wear (coded units)

Term Effect Coef StDev Coef T PConstant -0.000495 0.000235 -2.10 0.068A 0.000037 0.000019 0.000235 0.08 0.939B -0.000037 -0.000018 0.000235 -0.08 0.940C-Ctg 0.000219 0.000109 0.000235 0.47 0.654D -0.000045 -0.000023 0.000235 -0.10 0.925A*B -0.000094 -0.000047 0.000235 -0.20 0.847A*C -0.000095 -0.000047 0.000235 -0.20 0.845A*D 0.000422 0.000211 0.000235 0.90 0.396

Analysis of Variance for Rod (coded units)

Source DF Seq SS Adj SS Adj MS F PMain Effects 4 0.00000021 0.00000021 0.00000005 0.06 0.9922-Way Interactions 3 0.00000078 0.00000078 0.00000026 0.30 0.828Residual Error 8 0.00000707 0.00000707 0.00000088 Pure Error 8 0.00000707 0.00000707 0.00000088Total 15 0.00000806

Rod Ctg Wear for L8 Baseline: Cr, WC-Co

Differences in wear results are not statistically significant

Fractional Factorial Fit LG L8 1st Half Rep: Cr & WC-Co-Cr Ctgs

Estimated Effects and Coefficients for Rod Ctg Wear (coded units)

Term Effect Coef StDev Coef T PConstant -0.001419 0.000530 -2.68 0.028A 0.000857 0.000428 0.000530 0.81 0.442B -0.000377 -0.000189 0.000530 -0.36 0.731C-Ctg -0.001621 -0.000810 0.000530 -1.53 0.165D -0.000004 -0.000002 0.000530 -0.00 0.997A*B -0.000062 -0.000031 0.000530 -0.06 0.955A*C 0.000712 0.000356 0.000530 0.67 0.521A*D 0.000068 0.000034 0.000530 0.06 0.950

Analysis of Variance for Rod (coded units)

Source DF Seq SS Adj SS Adj MS F PMain Effects 4 0.00001401 0.00001401 0.00000350 0.78 0.5682-Way Interactions 3 0.00000206 0.00000206 0.00000069 0.15 0.925Residual Error 8 0.00003592 0.00003592 0.00000449 Pure Error 8 0.00003592 0.00003592 0.00000449Total 15 0.00005200

Ctg Wear for L8 1st Half Rep: Cr, WC-Co-Cr: Differences in wear results are not statistically significant

Bushing Wear with L8 Baseline: Cr,WC-Co: Differences in wear results are not statistically significant

Estimated Effects and Coefficients for Bushing Wear (coded units)

Term Effect Coef StDev Coef T PConstant -0.005305 0.001872 -2.83 0.022A -0.008400 -0.004200 0.001872 -2.24 0.055B 0.000125 0.000062 0.001872 0.03 0.974C -0.007712 -0.003856 0.001872 -2.06 0.073D 0.000341 0.000170 0.001872 0.09 0.930A*B 0.001658 0.000829 0.001872 0.44 0.670A*C -0.008178 -0.004089 0.001872 -2.18 0.060A*D 0.002326 0.001163 0.001872 0.62 0.552

Analysis of Variance for Bushing (coded units)

Source DF Seq SS Adj SS Adj MS F PMain Effects 4 0.00052065 0.00052065 0.00013016 2.32 0.1442-Way Interactions 3 0.00030014 0.00030014 0.00010005 1.78 0.228Residual Error 8 0.00044848 0.00044848 0.00005606 Pure Error 8 0.00044848 0.00044848 0.00005606Total 15 0.00126928

Ctg

Bushing Wear with L8 1st Half Rep: Cr,WC-Co-Cr Differences in wear results are not statistically significant

Estimated Effects and Coefficients for Bushing Wear (coded units)

Term Effect Coef StDev Coef T PConstant -0.005136 0.002698 -1.90 0.093A 0.003441 0.001721 0.002698 0.64 0.541B 0.000742 0.000371 0.002698 0.14 0.894C Rod -0.007399 -0.003699 0.002698 -1.37 0.207D Load -0.007929 -0.003965 0.002698 -1.47 0.180A*B -0.006588 -0.003294 0.002698 -1.22 0.257A*C 0.003687 0.001844 0.002698 0.68 0.514A*D 0.002968 0.001484 0.002698 0.55 0.597

Analysis of Variance for Bushing (coded units)

Source DF Seq SS Adj SS Adj MS F PMain Effects 4 0.0005200 0.0005200 0.00013001 1.12 0.4132-Way Interactions 3 0.0002632 0.0002632 0.00008773 0.75 0.551Residual Error 8 0.0009315 0.0009315 0.00011644 Pure Error 8 0.0009315 0.0009315 0.00011644Total 15 0.0017147

Statistical Model Wear Results

Load, lbs Cr Rod WC-Co AlAno vs Cr vs WC-Co72 -0.00067 -0.00052 -0.00006 -0.00927

288 -0.00024 -0.00009 0.00929 0.00008

ROD CTG OPPOSING BUSHING

Coatings Wear with Anodized Al Bushings

-0.020

-0.015

-0.010

-0.005

0.000

0.005

0.010

50 100 150 200 250 300Load, lbs.

Wea

r V

olu

me,

cc

Cr Rod

WC-Co

AlAno vs Cr

vs WC-Co

Ctg Wear with L8 2nd Half Rep: Cr,WC-Co(4340,Al anodize bushings)

Differences in wear results are not statistically significant

Estimated Effects and Coefficients for ROD Ctg (coded units)

Term Effect Coef StDev Coef T PConstant -0.000479 0.000177 -2.70 0.027A 0.000176 0.000088 0.000177 0.50 0.633B -0.000035 -0.000017 0.000177 -0.10 0.924C-Ctg 0.000142 0.000071 0.000177 0.40 0.699D 0.000054 0.000027 0.000177 0.15 0.882A*B 0.000052 0.000026 0.000177 0.15 0.887A*C 0.000012 0.000006 0.000177 0.04 0.973A*D 0.000375 0.000188 0.000177 1.06 0.321

Analysis of Variance for ROD (coded units)

Source DF Seq SS Adj SS Adj MS F PMain Effects 4 0.00000022 0.00000022 0.00000006 0.11 0.9762-Way Interactions 3 0.00000057 0.00000057 0.00000019 0.38 0.770Residual Error 8 0.00000402 0.00000402 0.00000050 Pure Error 8 0.00000402 0.00000402 0.00000050Total 15 0.00000482

Bushing Wear with L8 2nd Half Rep: 4340,Al anodize

Differences in wear results are not statistically significant

Estimated Effects and Coefficients for BUSHING Wear (coded units)

Term Effect Coef StDev Coef T PConstant -0.002698 0.001731 -1.56 0.158A -0.004990 -0.002495 0.001731 -1.44 0.188BUSHING 0.005314 0.002657 0.001731 1.53 0.163C -0.004918 -0.002459 0.001731 -1.42 0.193D 0.004202 0.002101 0.001731 1.21 0.260A*B 0.005092 0.002546 0.001731 1.47 0.180A*C -0.004292 -0.002146 0.001731 -1.24 0.250A*D 0.005145 0.002572 0.001731 1.49 0.176

Analysis of Variance for BUSHING (coded units)

Source DF Seq SS Adj SS Adj MS F PMain Effects 4 0.00037989 0.00037989 0.00009497 1.98 0.1912-Way Interactions 3 0.00028328 0.00028328 0.00009443 1.97 0.197Residual Error 8 0.00038364 0.00038364 0.00004796 Pure Error 8 0.00038364 0.00038364 0.00004796Total 15 0.00104681

Coating vs Seals Summary(Avgs of Orthogonal Arrays)

Material Seal orPair Rod Bush Bush+Seal Liner Visual

EHC - 4340 -0.000390 -0.000324 6.3WCCo - 4340 -0.000578 -0.010386 3.0WCCoCr - 4340 -0.001195 -0.010691 3.5

EHC Al Ni Bronze -0.000186 -0.005674 7.5EHC - Al Ni Bronze -0.000832 -0.002549 3.3WC-Co,Cr Al Ni Bronze -0.001323 -0.006980 4.3

EHC - Nitrile -0.024074 -0.000993 -0.283276 -0.282283 7.0EHC - Nitrile -0.000729 -0.000812 -0.099887 -0.099075 7.8WCCo - Nitrile 0.000678 -0.000904 -0.079644 -0.078740 1.5WCCoCr - Nitrile -0.000235 -0.002687 -0.176132 -0.173445 1.8

EHC Karon 0.000056 0.004556 1.8EHC Karon 0.001685 0.000910 1.5WC-Co Karon 0.000219 -0.000395 1.0WC-Co,Cr Karon -0.001813 0.000471 1.0

Wear Volumes

LG L8 5th Half Rep DOE Wear Volumes

-0.006000

-0.005000

-0.004000

-0.003000

-0.002000

-0.001000

0.000000

0.001000

0.002000

73A-E

HC/KARON/8

0K/7

2

73B-E

HC/KARON/8

0K/7

2

74A-E

HC/KARON/2

40K/2

88

74B-E

HC/KARON/2

40K/2

88

75A-W

CCoCr/KARON/8

0K/2

88

75B-W

CCoCr/KARON/8

0K/2

88

76A-W

CCoCr/KARON/2

40K/7

2

76B-W

CCoCr/KARON/2

40K/7

2

77A-E

HC/AlN

iBr/8

0K/2

88

77B-E

HC/AlN

iBr/8

0K/2

88

78A-E

HC/AlN

iBr/2

40K/7

2

78B-E

HC/AlN

iBr/2

40K/7

2

59A-W

CCoCr/AlN

iBr/8

0K/7

2

59B-W

CCoCr/AlN

iBr/8

0K/7

2

60A-W

CCoCr/AlN

iBr/2

40K/2

88

60B-W

CCoCr/AlN

iBr/2

40K/2

88

ROD

BUSHING

Karon B Seals AlNiBronze Bushing

EHCEHCWC-Co,Cr WC-Co,Cr

Statistical Model Wear Results for Nitrile Seals in 4340 Bushings

Load, lbs Cr WC-Co WC-Co-Cr vs Cr vs WC-Co vs WC-Co-Cr72 -0.00100 0.00015 -0.00678 -0.48422 -0.27582 -0.17768

288 0.00039 0.00153 -0.01078 -0.25726 -0.04886 -0.15875

ROD CTG OPPOSING BUSHING+Seal

Coatings & Nitile Seals Wear

-0.50

-0.40

-0.30

-0.20

-0.10

0.00

50 100 150 200 250 300Load, lbs.

Vo

lum

e W

ear,

cc

Cr

WC-Co

WC-Co-Cr

vs Cr

vs WC-Co

vs WC-Co-Cr

Estimated Effects and Coefficients for ROD CTG Wear (coded units)

Term Effect Coef StDev Coef T PConstant -0.006091 0.005873 -1.04 0.330A 0.012035 0.006017 0.005873 1.02 0.336B -0.011212 -0.005606 0.005873 -0.95 0.368C 0.012282 0.006141 0.005873 1.05 0.326D -0.011080 -0.005540 0.005873 -0.94 0.373A*B 0.011895 0.005947 0.005873 1.01 0.341A*C -0.011135 -0.005568 0.005873 -0.95 0.371A*D 0.012467 0.006234 0.005873 1.06 0.319

Analysis of Variance for ROD (coded units)

Source DF Seq SS Adj SS Adj MS F PMain Effects 4 0.002177 0.002177 0.0005442 0.99 0.4672-Way Interactions 3 0.001684 0.001684 0.0005612 1.02 0.434Residual Error 8 0.004415 0.004415 0.0005518 Pure Error 8 0.004415 0.004415 0.0005518Total 15 0.008275

Ctg Wear for L8 3rd Half Rep: Cr, WC-Co

Differences in wear results are not statistically significant

Ctg Wear for L8 6th Half Rep: Cr,WCCoCr Differences in wear results are not statistically significant

Estimated Effects and Coefficients for ROD Ctg Wear (coded units)

Term Effect Coef StDev Coef T PConstant -0.000748 0.000299 -2.50 0.037A 0.000334 0.000167 0.000299 0.56 0.591B 0.000066 0.000033 0.000299 0.11 0.915C -0.000531 -0.000266 0.000299 -0.89 0.400D -0.000434 -0.000217 0.000299 -0.73 0.489A*B 0.000861 0.000431 0.000299 1.44 0.187A*C 0.000179 0.000090 0.000299 0.30 0.771A*D -0.000429 -0.000214 0.000299 -0.72 0.493

Analysis of Variance for ROD (coded units)

Source DF Seq SS Adj SS Adj MS F PMain Effects 4 0.00000235 0.00000235 0.00000059 0.41 0.7962-Way Interactions 3 0.00000383 0.00000383 0.00000128 0.89 0.485Residual Error 8 0.00001142 0.00001142 0.00000143 Pure Error 8 0.00001142 0.00001142 0.00000143Total 15 0.00001759

Nitrile Wear for L8 3rd Half Rep: Cr,WC-Co Differences in wear results ARE statistically significant

Estimated Effects and Coefficients for Bushing+Seal (coded units)

Term Effect Coef StDev Coef T PConstant -0.09341 0.01480 -6.31 0.000A -0.09012 -0.04506 0.01480 -3.04 0.016B CTG -0.17611 -0.08805 0.01480 -5.95 0.000C Seal 0.09678 0.04839 0.01480 3.27 0.011D Load 0.12011 0.06005 0.01480 4.06 0.004A*B -0.08003 -0.04002 0.01480 -2.70 0.027A*C 0.11162 0.05581 0.01480 3.77 0.005A*D 0.10685 0.05342 0.01480 3.61 0.007

Analysis of Variance for Bush+Seal (coded units)

Source DF Seq SS Adj SS Adj MS F PMain Effects 4 0.25171 0.25171 0.062928 17.94 0.0002-Way Interactions 3 0.12112 0.12112 0.040373 11.51 0.003Residual Error 8 0.02806 0.02806 0.003507 Pure Error 8 0.02806 0.02806 0.003507Total 15 0.40088

Nitrile Wear for L8 6th Rep: Cr,WC-Co-Cr Differences in wear results are not statistically significant

Estimated Effects and Coefficients for Bushing+Seal Wear (coded units)

Term Effect Coef StDev Coef T PConstant -0.07231 0.02507 -2.88 0.020A -0.01612 -0.00806 0.02507 -0.32 0.756B -0.04219 -0.02110 0.02507 -0.84 0.425C Seal 0.13139 0.06569 0.02507 2.62 0.031D -0.01512 -0.00756 0.02507 -0.30 0.771A*B 0.02540 0.01270 0.02507 0.51 0.626A*C 0.02749 0.01375 0.02507 0.55 0.598A*D 0.03405 0.01703 0.02507 0.68 0.516

Analysis of Variance for Bush+Sea (coded units)

Source DF Seq SS Adj SS Adj MS F PMain Effects 4 0.078128 0.0781284 0.019532 1.94 0.1972-Way Interactions 3 0.010242 0.0102415 0.003414 0.34 0.798Residual Error 8 0.080458 0.0804585 0.010057 Pure Error 8 0.080458 0.0804585 0.010057Total 15 0.168828

Ctg Wear for L8 4th Rep: Cr,WC-Co

(4340 and Karon B Bushings) Differences in wear results are not statistically significant

Estimated Effects and Coefficients for BUSHING (coded units)

Term Effect Coef StDev Coef T PConstant -0.001637 0.002061 -0.79 0.450A -0.005106 -0.002553 0.002061 -1.24 0.251B Ctg 0.007436 0.003718 0.002061 1.80 0.109C Seal -0.007507 -0.003753 0.002061 -1.82 0.106D 0.003680 0.001840 0.002061 0.89 0.398A*B 0.004975 0.002488 0.002061 1.21 0.262A*C -0.004814 -0.002407 0.002061 -1.17 0.277A*D 0.002556 0.001278 0.002061 0.62 0.553

Analysis of Variance for BUSHING (coded units)

Source DF Seq SS Adj SS Adj MS F PMain Effects 4 0.00060503 0.00060503 0.00015126 2.22 0.1562-Way Interactions 3 0.00021785 0.00021785 0.00007262 1.07 0.415Residual Error 8 0.00054388 0.00054388 0.00006798 Pure Error 8 0.00054388 0.00054388 0.00006798Total 15 0.00136675

CONCLUSIONS

• Coating Wear showed very little difference between Chrome and the HVOF carbides– No statistically significant differences

throughout test program

• Opposed Surface Wear favors Cr– Largest statistical significance with Nitrile seals

• WC-Co-Cr Favored over WC-Co– When statistically significant differences

• Karon B Wear best against all coatings