NASA CR-ISMSO R78AEQ476

ROLLING ELEMENT FATIQUE TESTING OF GEAR MATERIALS

FINAL REPORT

BY

A.H. NAHM

GENERAL ELECTRIC COMPANY JUNE 26, 1978

( h ! A S h - ; 7 - 1 3 5 3 5 f ' ) E D L L I N G ELEMY'JT F 9 T I S q E TFSTIXG CF S E A R Y A T E F I A L S F i n 3 1 Report , Apr. :C177 - J - ~ n . 1978 (<;enera1 ' l e c t r i c r o , ) 1 2 4 p '!C tO6/YF a91 CSCL 14C

PREPARED FOR

National Aeronautics and Space Administration

R.J. PARKER, PROJECT MANAGER

NASA Lewis Research Center NAS3-14302

https://ntrs.nasa.gov/search.jsp?R=19780025520 2018-10-06T14:41:08+00:00Z

A. H. Nahm R78AECi476

A hrtumiq Otpnlratmn N a m md M&rr Material & P r o c a r r Technolony Laboratorisr

1. Itcporl No. 2. Gownmmc LKnu(on No. NASA CR-135450

4. Titk nd Subcttlr

Rolllnp Elemant Fatigue Tert ing of Gear Materiala - Final Report

-. Aircra f t Engine Group General Electr ic Company

3, Rwip~nt'a Catalog No.

5. R m r OItr 26 June 1978

' 6 ~ r t w n ~ ~ ~ i r a t t m ~ ~ d ~

11. OMItrut of Grant NO 1 NAS1-14302 Cincinnati, Ohio 4521 5 -

13. T v p of R m t bnd P*td Cowd

I?. SgMcorlng +v Nmw wwl *ddna Contract Report - Flnal National Aaromut ic r & Space Adminiatration r ~YZZA~UJ-~ , . Lewir Rerearch Center 14. Spanmntng A p c y Bd,

I - Cloveland, Ohio 441 35 - 6. supdrnmtwv Now

Pro jec t Manager - R. J. P a r k e r Bearing, Cearinp & Trrnanriar ion .Section

Rollin8 sloment fatigue liver of nine rlloyo were cvrluatad in the General Electr ic Rolling Contact (RC) r ips . Tar t conditlonr ured in the CiE RC r igs with cylindrical specimens inclodad a Hertaian s t r e s e ~t 4.82h M P r (700 h i ) , r rolling rpeed of t i .23 r n / a ~ c (245 in/oec.) . Teatr were run with a Type I d l (MIL-1 . . 710BC1) a t roonr tcnrperature. h4etalluryical analyror wnro mads before and af tar the PC rig teats. Test data ware ntatlatically analyzed uciing !he Wcibrrll darlribution function. 8 - 1 0 l iver (10% f.~ilure rdte) of r l lnyr were cunrparcd versus ruferenee alloys, VIM-VAR AlSl M- 40 and VAR A M 931 0.

Six e a r s carburicing alloyr (AISI 9310. CBS60O. CBSlOOOM, EX00014, Vanca X - 2 and EXO0053) and three th rough-h~rdening alloys (AM1 hl-60. VarcuMux 330 and Vasro Matrix It) evaluated in thir study ahowed RCF perl 'ornrrnre infer ior o r equivalent to that o f AISI 9310 and A S 1 M - $ 0 . It wan alao i w n d that the effccta of v r c u u n ~ nwltiny procssuen, different tempering tanqmruturer t f raet lny cycle during heat treating. shot proning, gold plating and c h r o ~ n e plating nmpluycci in the present invextigatio~: did not aigniftr.antly pact R C F lile.

--- ------ I. Krv War* 1Sugpct.c' t v A t ~ l h a l a l ) Rolling Elonrant Fatigue, GI,: IIC Rig. Deiirinu and Coar Alloys, C a m Hardening, (:hronrc and Cold Plating, Shot P n r n i n ~ , tieut Treating. Vacuum Melting P r o r e r u , Micrcmtr~ir ture

l lnclrr xificcl - Puhlicly Avnil.tblc

-- thtr ~raw)

FOREWORD

This program was conducted by the Mater ia l and P r o c e s s Technology

Laborator ies , A i r c ra f t Engine Group, General E lec t r i c Company,

under NASA Contract NAS3-14302. The NASA Technical P r o j e c t Manager

was Mr. R. J. P a r k e r of the Bearing, Gearing and Transmis s ion Section,

NASA -Lewis Resea rch Center , Cleveland, Ohio 441 35. The Technical

P ro j ec t Manager for General Elec t r ic was M r . D. B. Hes ter .

ACKNOWLEDGEMENTS

The author acknowledges the valuable guidance of Mess r s . E. N. Bamberger, and F. C. Robertshaw during the ent i re c o w ae of the invc etigation.

The author wishes to thank the Timken Company personnel for help in heat treating of their alloys.

Finally, the contributions of Messrs . D. J. Kroeger and S. A. Leighton, who performed the testing and evaluation essential in this type of study, are a lso gratefully acknowledged.

TABLE O F CONTENTS

SECTION ABSTRACT

FOREWORD

ACKNOWLEDGEMENTS

INTRODUCTION

a) Rolling Contact Fatigue Test ing

b) Metallurgical Evaluation of T e s t Mater ia l s

c ) Fatigue Data Analys i s

RESULTS AND DISCUSSION

AISI M - 50

AISI 9310

EX0001 4

C BS6OO

EX00053

CBS100OhiI

Vasco 5 - 2

VascoMax 3 5 0 & Vasco Matrix I1

IV.

v.

VI.

SUMMARY AND CONCLUSIONS

REFERENCES

APPENDICES

A. Chemica l Composition of T e s t Materials for P h a s e III

TABLE OF CONTENTS (Continued)

SECTION

B, Physical Properties of Lubricant

C. Rolling Contact Fatigue Test Data (Tables)

D. Rolling Contact Fatigue Test Data (Figures)

E. Summary of RCF Test Results and Metallurgical Characteristic s of Test Materials for Phase IU

PAGE

76

7 7

9 3

109

TABLE

1

2

3

LIST O F TABLES

Chemical Composition of AISI M - SO

Heat Treating P r o c e s s for AISI M- SO

Summary of Tes t Results and Metallurgical Character is t ics of AISI M - 50

Chemical Composition of AISI 931 0

Heat Treating P r o c e s s for AISI 931 0

Summary of RCF Test Results and Metallurgical Character is t ics of AISI 9310

Heat Treating P r o c e s s for VAR EX00014 (Tes t Ser ies AS)

Summary of R C F Tes t Results and Metallurgical Characteris t ics of EX00014

Chemistry Specification for CBS600

Chemical Composition of CBS600

Heat Treating P r o c e s s for CBS600

Summary of R C F Test Results of C DS6OO

Metallurgical Case and Core Characteris t ics of CBS600

Chemical Composition of VAR EX00053

Heat Treating P r o c e s s for VAR EX09053

PAGE

11

12

13

LIST O F TABLES (Continued)

TABLE

16

PACE

44 Summary of R C F Tes t Resu l t s and Metal lurgical Cha rac t e r i s t i c s of EX00053

Chemica l Composition of CBSlOOOM

Heat Treat ing P r o c e s s for C BSl OOOM

Summary of R C F T e s t Resul t s and Metal lurgical Cha rac t e r i s t i c s of C BSIOOOM

Chemical Composition of Vasco X-2

Heat Treat ing P r o c e s s for Vasco X-2

Summary of R C F Tes t Resul t s and Metal lurgical Cha rac t e r i s t i c s of Vasco X - 2

Circi lmfcrent ia l Residual S t r e s s Distributions in As -Received Vasco X-2 Specimens

Chemical Composition of VascoMax 350 and Vasco Mat r ix I1

Heat Treat ing P r o c e s s for VascoMax 350 and Vasco Matr ix I1

Summary of R C F Tes t Resul t s and Metal lurgical Cha rac t e r i s t i c s of VascoMax 350 and Vasco Mat r ix I1

Chemica l Composition of Tes t Mater ia l s for P h a s e 111

Phys i ca l P r o p e r t i e s of Lubricant , Stauffer J e t I (MIL -L-7808G)

TABLE

29

LIST OF TARLES (Continued)

Rolling Contact Fatigue Tes t s - VIM-VAR AISI M-50 (Test Ser ies AG)

Rolling Contact Fatigue Tes t s - AM CBS600 (Tes t Ser ies AH)

Rolling Contact Fatigue Tes ts - VAR CBSl OOOM 7 9 (Tes t Se r i e s AI)

Rolling Contact Fatigue Tes ts - VAR Vasco X-2 80 (316°C Temper) (Tes t Series AS)

Rolling Contact Fatigue Tes ts - VAR Vasxo X-2 8 1 (510°C Temper) (Test Series AK)

Rolling Contact Fatigue Tes ts - VAR Vasco X-2 (316°C Temper) (Test Ser ies A L )

Rolling Contact Fatigue Tes ts - VAR Vasco X-2 8 3 (316°C Temper + Shot Peened) (Test Ser ies AM)

Rolling Contact Fatigue Tes ts - VAR VascoMax 84 350 ('Test Series AN)

Rolling Contact Fatigue Tes ts - VAR Vasco Matrix 85 I1 (Tes t Ser ies AO)

Rolling Contact Fatigue Tes t s - VAR AISI M - 50 86 (Tes t Se r i e s A P )

Rolling Contact Fatigue Tes ts - VAR AISI 931 0 87 (Tes t Ser ies AQ)

Rolling Contact Fatigue Tes t s - VIM-VAR AISI 9310 88 (Tes t Ser ies AR)

- viii -

LIST O F TABLES (Continued)

TABLE

41 Rolling Contact Fatigue Tes t s - VAR EX00014 89 (Tes t Ser ies AS)

Rolling Contact Fatigue Tes ts - VAR EX00053 90 (Tes t Ser ies AT)

Rolling Contact Fatigue Tes t s - VIM-VAR AISI M- 50 9 1 (Cold Plated) (Test Ser ies AU)

Rolling Contact Fatigue Tes ts - VIM-VAR AISI M-50 9 2 (Chrome Plated) (Test Ser ies AV)

Summary of RCF Test Results and Metallurgical 109 Characteris t ics of Tes t Materials for Phase I11

LIST O F FIGURES

FIGURE

1

2

3

4

5

6

7

8

9

10

1 1

1 2

13

14

Ovesview, GE R C R i g

Closeup, Specimen and R o l l e r G r o m e t r y in R C R i p

RC Rig Spec imen G e o m e t r y and Specif ica t ion

Typical Roll ing Contact Fa t igue F a i l u r e in C BS600

Fatigue Life C o m p a r i s o n of AlSI M-56

R-10 Fat igue Life of AISI h l -50

Opt ical h l i c r o s t r u c t u r e of AISI h l -50 ; 3'';) Nital Etch: (a) - VAR AISI h i -50 (Test S e r i e s A P ) (b) - VIhl-VAR -41.51 hl -50 (Test Sr r i e s A(;. At7 A A V )

Optical hlic r o g r a p h s Showing C a r b i d e s in AISI h i - 60; 3?'0 Nital Etch: ( a ) - VAR AISI h . l - q U (Test Series A P ) (b) - VIhl-VAR AISI h i - 50 (Test Series AG. A l l b A V )

Optical hlic ros t r i i c tu rc of AISI hl- 50: 3Yb Ni ta l Etch: (a) - Gold P la ted VIM-VAR AISI hi -50 ('Test Series Al!) ( b ) - Chrome Pla ted VIhl- VAR AISI h l -50 ( T e a t Series A?')

Fat igue Life Comparison of AISI 9310 2 3

B- 10 Fatigue Life C o m p a r i s o n of AISI 0310 2 4

Optical hlicrostructi trc. of VAR AISI Q310. T e s t Series 2 s AQ, Nitnl Etch

Optical h l i c r o s t r u r t u r c of VIhjI-VAR AISI Q310. T e s t 2 tl Serit.8 AR, Nital Etch

Opt ical h l i c r o s t r ~ i c t u r e ol' VAR ES00014, T e s t 2 Q

S e r i e s AS, Nital E tch

LIST O F FIGURES (Continued)

FIGURE

15

16

17

P A G E

3 6 Fatigue Life Comparison of CBS600

B-10 Fatigue Life Cornparisone of CBS600 3 7

Optical Microstructure of CBS600, Test Series AH, Picral Etch

Optical Mic roatructure of CBS600, Test Series AH, 39 Nital Etch

Optical Microstructure of EX00053, Test Series 4 5 AT, Nital Etch.

Optical hiic rostructure of C BS1 OOOM, Test Series AI, Nital Etch

Fatigue Life Comparison of CBSlOOOM 50

B- 10 Fatigue Life Comparison of C BS1000hI 5 1

Fatigue Life Comparison of Vasco X-2 5 7

B-10 Fatigue Life Comparison of VAR Vasco X-2 5 8

Microstructure of Vasco X-2, Test Series A J , Picral 59 Etch

Microstructure of Vasco X-2, Test Series AK, Nital Etch

Microstructure of Vasco X-2, Test Series AL, 6 1 Picral Etch

Microstructure of Vasco X-2, Test Series AM, 6 2 Picral Etch

Circumferential Residual Stress a s a Function of 6 3 Depth Below Surface of Vaeco X-2 Specimens

Optical Microstructure of VascoMax 350, Test 6 8 Series AN, Nital Etch

LIST O F FIGURES (Continued)

FIGURE

3 1

PAGE

6 9 Optical Mic roatructure of Vasco Matrix 11, Test ,Series A O , Nital Etch

Fatigue Life Comparison of VascoMax 350 and Vasco Matrix II

R C F Test Kesillts of V I M - V A R AISI hl-50 (Test Series AG)

R C F Test Results of A M CBSbO0 (Test Series A H )

R C F Test Results of V A R CI3S1000hI (Tes t Serics A I )

R C F 'Test Results of VAR Vasco S-2 (Tcst Series AJ)

RCF Tcst Iirsultv of V A H \ ' i isco S - 2 (Tes t Series AK)

RCE' Test Results ( 7 : ' \'AR Vasco S - 2 (Tcs t Series A L )

RCF Test Results of \'AH Vaaco ? ; - 2 (Shot P e e n e d ) (Tcst Series AX{\

RCF Test Results of VAR Vnocohlax 350 (Tcst Serics A N )

HCF Test Results o f VAR \ ' ~ P C O htatrix I1 (Test Series AOl

RCE' Tes t Kcsult A of \'AR AISI hf- GO (Test Serics A P )

KCF Tesr R-stilts ot V A R AISI 331 0 (Test Series AC)!

R C F Test Resttlts of V I h I - \ ' A R AISI Q 3 l O ( T e s t Seric-o AKl

- sii -

--2

FIGURE

45

4 6

47

48

LIST OF FIGURES (Continued)

RCF Test Results of VAR EX00014 (Test Ser ies AS)

RCF Test Results of VAR EX00053 (Test Ser ies AT)

RCF Test Results of VIM-VAR AISI M-50 (Gold Plated) (Test Ser ies AU)

RCF Test Results of VIM-VAR AISI M-50 (Chrome Plated) (Test Ser ies AV)

- xiii -

PAGE

105

106

107

lo8

INTRQDUC TION

Ganoral Electr ic Company, undar contract to NASA -Lewicr Research Center, hwr conducted this program t o investigate the rolling e l ~ r n e n t fatigue characteris t ics sf advanced bearing and gear mate riala.

Aviation tranamiasion ayeternr, a r e expected to be operated a t higher temperature with increased Load capacity. This is a ~ e n a r ~ l requirement toward better efficiency, not only in cnnrmercial jet engines, but a l w special engines i n V/STOL or SST ai rcraf t ,

AISI 9310 has b a n most widely usad as w standard aviation alloy twcsuse of i ts ease of processing and excellent case and core proportias. How- ever , i t i s l in~i ted to applications wlwre rnaxin~um oporatlng tenlperatures do not exceed 1SO'C (300.F). There is a dofinite nccd fnr higher temper- ature p a r materials. The I-r-rnterialu must ha equal to or batter t lu~n AISI 9310 in t e r m s of pt+rforrnanc.e, processing, and reliability nt elevated tan1perntura((?00"C;-)., (400" E't )).

There i s also a need for yooci I~carinp ~rlntariala , a s \\.ell nn good gear mater ia ls due to incrc:asati irsa o f intc-yral b e u r i n ~ f p c a r deaigtrs. Fur example: halicoptor nutin rotor trc~nsnliszsion tiyett~ms.

This contrac-t, which has been underway sirrw 1Q70, h,r s t*~ic.o~np;rssccl several related etirdics:

b) In Tasks IX through XN, R C F testing of and csubaequcnt metal l- urgical evaluation of eleven candidate alloys (Phaee I) were undertaken. Additionally, the effects of different heat treating processes and additional vacuum melting proceeaes on the RCF life of severa l selected c a s e carburieing alloys (Phaee 11) were determined, The rssul ta were compared with the standard aviation bearing and gea r allays, VIM-VAR AISI M- SO and VAR AISI 9310, reepectively. The work covering the Task 1X through XI11 (Phaee I and I1 gear materials) has been reported as an interim report. ( 5 )

The purpose of this repor t is to document the! final phase (Phaee 111) of the contract comprising Tasks XIV and XV. Several of these mater ia ls are from the same heats of mater ia l and melting process as gea r s used in full-scale spur gedr tes ts to h perlormcd by NASA. This phase includes RCF testing and n~cta l lurgica l evaluation of Phase 111 mater ia ls a s follows:

PHASE III TESTS

Test Se ;*ie s --

P G

A i-I

A1

AJ

AK

A L

AM

AN

A 0

Melting P r o c e s s

VIM -\ A R ( ~ )

AM(')

VAR

VAR

VAR

VAR

VAR

Test Material R e m a r k s

replaces V A R Nitralloy (b)

- tc.n.rpcreci a t 31 6°C (600° F')

tr-nlpcred at f i l O O C (1000" F)

t e n ~ p e r ~ d at 3 1 i t " C. (000" F)

t e ~ i l p c red at 3 1 6" C i6OO0 F), shot pee twd

VAR

VAR Vasco Matrix JI

(a) - Vacuum induction rnrlted (VIM) followed by vacuum a r c remelted (VAR).

(b) - Initially rcl~cduLcd m a t r r i d a replaced due to unsatisfactory specimuns or unavailability of spcoin~env.

(dl - Test matorial8 f rom Sitme heats o f mater ia l or gea r s to be tcstcd by N A S A .

Te rt Se rie ,

Meltin8 Proce e e

VAR

VAR

VIM-VAR

VAR

VAR

VIM -VAR

VIM - VAR

PHASE I11 TESTS (Continued)

Teat Mate rial Remarks

AISI M-50

AJSI 9310

AISI 9310

EX0001 4

EX00053

AISI M - 50

AISI M-50

- replaces REX 729 (b)

- - ..

gold p lated

chrome -plated

(b) - Initially schodulcd materials replaced due to unsatisfactory specimens or iu~availability of specimens.

11. EXPERIMENTAL

Sixteen Phase 111 mate r i a l s w e r e tested in the General Elec t r ic rolling contact (RC) fatigue rigs. The chemical compositions for Phase If1 ma te r i a l s a r e given in Appendix A. The effects of tempering, vacuum melting, shot peening, and gold and chrome plating on rolling contact fatigue were evaluated. Metallurgical aqalyses were made before and after the RC rig tests . Tes t data were analyzed stat is t ical ly using the Weibull distribution function.

a Rolling Contact Fatigue Testing

The Rolling Contact (RC) fatigue tes t r igs have been used since 1957 to evaluate bearing / gear alloys and mate r i a l s / lubricants interact ions . Photographs of RC r igs a r e shown in Figures 1 and 2. The detailed teating procedure is described elsewhere. ( 6 )

Experimental tes t conditions used in RC r igs were a s follows:

Maximum Hertzian St re s s: 4,826 MPa (700 ksi)

Rolling Speed : 6.23 m / s e c (245 i n / s e c )

Lubricant : MIL-L-7808

Temperature: Room-ambient

Load is z , plied to produce Hertzian contact s t r e s s by closing two identical seven-inch diameter ro l lers with a crown radius of 6. 35 mm (0.25 in) against a cylindrical tes t bar 76.2 mm(3 in) long, 9 . 525 m m (0.375 in) diameter . Figure 3 shows the drawing for specimen geometry and specification. The ro l l e r s a r e made of CVM AISI A l - 50, pe r AMS b490, with a hardness of I-IRC 6321.

Stauffer J e . 1 brand (MIL-L-7808) oil i s supplied to the contacting surface^ by dr ip feeding approximately 20 drops per minute. Physical propert) data of the lubricant a r e given in Appendix B.

Tedt bars and ro l l e r s were finish ground to surface roughness of 6-8 p in (0.15 - 0.20 )(I r m s and 8-12 /A i n (0.20 - 0 . 3 0 p ) r m s , P '

respectively, The composite surface roughness, i s est imated using C

this relationship:

w h e r e c and r a r e the surface roughnesses of the mating par ts . 2

The sur tace roughn.sses of test ba r s and a new se t of r o l l e r s rapidly change to smoother surfaces af ter a shor t period of testing time, while the surface roughnesses degrade gradually a s the testing t ime i s increased. Consequently, the composite surface roughness is est imated to be 10 - 25 in (0.25 - 0.64 1. P P' Cheng's formula('l) was used to calculate the minimum oil f i lm thickness,

hmin. Based on viscosity of the lubricant a t 38'C (lOO°F), the film thickness is 8.3 Min (0.21 mm). Therefore, the specific f i lm thickness rat io = hmin ii considered to be in par t ia l elastohydrodynamic lubrication -

6;: -

regime, typical of bearing and gea r applications.

Fai lure mode observed in RCF testing was of c lass ica l subsurface initiated fatigue spalling o r ~ i t t i n g , charac ter is t ic of that observed in bearings and gears . A rolling fatigue failure of CBS600 i s shown in Figure 4 a s an example.

b) Metallurgical Evaluation of Tes t Materials

Hardness in Rockwell C (HRC) converted f rom Rockwell 1 5 -N was measured on each tes t bar before R C F testing. Microhardness measurements were made to determine the effective c a s e depths of the case hardened mater ia ls . The effective case depth i s defined a s the depth below surface a t which hardness is HRC 58, Conventional optical metallographic specimens were prepared to examine the mic ros t ruc tu re before and after the testing.

Volume percent of retained austenite was determined on the surface of tes t specimens with an X-ray metallographic technique. The technique involves the measurement of X-ray peaks intensity diffracted f rom (200) planes of austenite and mar tens i te s t ruc tures . Chromium K& radiation a t 50 kv was used to obtain the X-ray diffracted peaks.

C ) Fatigue Data Analysis

Rolling contact fatigue data were analyzed in the Weibull distribution function and statistically considered in a manner suggested by Johnson.(8) The fatigue life in number of s t r e s s cycles a s absc issa ve r sus the stat is t ical cumulative fai lures a s ordinate were plotted in the Weibull probability graph. B-10 o r B-50 lives a r e defined he re a s the number of cycles where 1070 o r 50%, respectively, of the test population a r e expected to fail in spalling fatigue. Since ea r ly fai lures in contact fatigue a r e much more significant in engineering pract ice, B-10 life was used a s a cr i te r ion to evaluate the rolling contact fatigue life performance.

OHiCLNAI, PAGE LS OF POOR QUALITY

1 RESULTS AND DISCUSSION

Rolling contact fatigue t e s t resul t s of Phase 111 t e s t series a r e given in Appendix C. Corresponding Weibull plots a re a l s o included in Appendix Dm A summary of t e s t resul t s and meta l lwgica l analyses on Phase 111 mate r i a l s a r e shown in Appendix Eo Data for VIM-VAR AISI M-50 and VAR AISI 9310 a r e included in the Appendix E a s a baeeline, AISI M-SO data are based on more than 250 R C F tes t s with 12 different heats which w e r e heat t reated to I-IRC 63t1. - F o r convenience, this chapter i s categorized according to mater ia ls .

a ) AISI M - 50

Four t e s t s e r i e s were done in Phase 111, a s follows:

Tes t Se r i e s Melting P r o c c s s

VIM -VAR

VAR

Remarks

AU VIM -VAR gold plated

AV VIM -VAR chronle plated

Chemical composition for AISI M - 50 tes t s e r i e s i s given in Table 1 . Heat treating process for AISI M-50 tes t speriimens i s described in Table 2.

Ion plating of VIM-VAR AISI M-50 test specimens with chrome and gold were performed in a vacuum chambcr. Electrical potential between cathode and anode was between 3000 and 5000 volts DC. Final plating thickness was controlled to be 1800t300 - angst roms (7.1 - t 1 . 2 p in.) on both specimens. Puri ty of the gold and chromc anodes w e r e

99.9399410 and 99.9099'0, respectively.

Table 3 ehows a summary of R C F tes t resul t s and ~ne ta l lu rg ica l analyses of AISI M- 50. Weibull plots a r e shown in Figure 5. B- 10 lives a r e shown a s histogram in Figure 6.

Optical micros t ructures of VAR hl-50 ( tes t s e r i e s A P ) and VIM-VAR M- 50 ( test s e r i e s AC, AU and AV) a r e shown in Figures 7 and 8. No noticeable differences were found except the VAR AISI M - 50 specimens (Figure 8 -a ) has fewer carbides than the VIM-VAR AlSI M-50 (Figure . , -b), Retained austenite was not detected with X-ray diffraction technique in any of the AISI M-50 specinlens. This means that the volume percent

TABLE 2

HE

AT

TR

EA

TIN

G PROCESS FOR A

ISI M- 50

He

at

Te

st

Se

rie

s A

G

Tre

ati

ng

V

IM - V

AR

Pre

he

at

81

6°C

(I

'00

°F)

in s

alt

fo

r 1

5 m

inu

tes.

20

40

' F

) in

sa

lt f

or

5 m

inu

tes.

Qu

en

ch

5

79

°C (

10

75

' F

) fo

r 1

0 m

inu

tes,

a

ir

co

ol

to 6

Ca

C 1

1 50

" F

) o

r l

ow

er.

Te

mp

er

54

8°C

(1

02

0" F

) fo

r 2

ho

urs

, a

ir cool.

Dee

p F

ree

ze

-7

3°C

(-1

00

°F

) for

2 h

ou

rs,

air

wa

rm.

Te

mp

er

54

8°C

(1

02

0" F) for

2 h

ou

rs,

air

co

ol.

Pla

tin

g

- -

Te

st

Seri

es

AP

T

es

t S

eri

es

AU

V

AR

V

IM-V

AR

81

6°C

(1

50

0°F

) in

sa

lt

for

30 m

inu

tes.

I

11

13

°C (

20

35

°F)

in

salt

fo

r 6

min

ute

s.

57

4"

C f

10

65

" F) f

or

I sa

me

as T

es

t 2

0 m

inu

tes,

a

ir

Se

rie

s A

G

55

2°C

(1

02

5°F

) fo

r 2

ho

urs

, a

ir

co

ol.

-73

°C (

-10

0°

F)

for

2 h

ou

rs.

55

2°C

(1

02

5"

F)

icr

2 h

ou

rs,

air

cool.

i - -

I g

olu

pla

ted

Tes

t S

erie

s A

V

VIM

-VA

R

sam

e a

s T

est

Seri

es A

G

chro

me

pla

ted

Ser

iem

R T

AB

LE

3

SUMMARY O

F T

ES

T R

ES

UL

TS

AN

D M

ET

AL

LU

RG

ICA

L C

HA

RA

CT

ER

IST

ICS

OF

AfS

I M

-50

I Ba

se-

I I

I

VA

R

I 2

.46

I

4.0

1

3. b

5

Mel

tin

g

Pro

ce

ss

VIM

-VA

R

10

.66

vm

-VA

R

--

Fa

ilu

re*

H

ard

nas

m

Re

tain

ed

N. D.

**

Wei

bu

ll

Slo

pe

B- 0

Lif

e

f?

, x

10

C

yc

les

60

.6

[ N.D.

2.2

3

B-1

0 L

ife

,

x1

0~

Cy

cle

s

VIM

-VA

RI

3.3

4

63

.0

/ N

.D.

7.7

7

Te

st

Co

nd

itio

ns:

Max

. H

z S

tre

as:

4

,82

6 M

Pa

(7

00

ksi

) S

pee

d:

6.2

3 m

/se

c (

24

'5 i

n/s

ec

) L

ub

ric

an

t:

MIL

-L-7

80

8

Te

mp

era

ture

: R

oo

m -

am

bie

nt

*N

um

ber

of

tests

to

fa

ilu

re o

ut

~f t

ota

l n

um

be

r o

f te

sts.

**N

ot

de

tec

ted

by

X-r

ay

dif

fra

cti

on

tec

hn

iqu

e.

C..

.

.. ..

i i

n -

Test Series AP,

VAR

Test Series AV,

! chrome-plated,

250 tests

Test Series PU,

/ gold-plated,

VI M-VA R

Test Series AG,

Test Conditions

Smax

= 4,826 MPa(700ksi)

Speed =

6.23

dsec

Lubricant - M

IL-L-7808

Temperature -

Room-ambient

FATIGUE LIFE, SrliESS CYCLES

Figure 5.

Fatigue Life Comparison of AISI M50.

V I hi-VAH , V I hl-VAR g o l d - p l a t e d 12 h e a t s ,

VIM-VAR 250 tests

VIh1-VAR, V AR chrome-pla t e d

-

Tos t S e r i e e AG AP AU AV B a s e l i n e

F igure 6 , B-10 F a t i g u e L i f e of AISI M-50.

Figure 7 . Opt i ca l Microstructure of AISI M-50, N i t a l Etch: (a) VAR AISI M-50 (Test S e r i e s AP) and (b) VIM-VAR AISI M-50 (Test S e r i e s AG, AU & AV)

16

ORIGINAL PAGE IS OF F'OOR QUALITY

-------7 - " =Wf----'~ 1 1, "T--- L i .. ).

of ;etained austeni te was below 2%. T e s t s e r i e s AG (VIM-VAR AISI M-50) shows B-10 life of 3 . 3 4 ~ 1 0 ~ cyc les , being c lose to thht of baseline data for VIM-VAR AISI M- 50. VAR AISI M-50 ( tes t s e r i e s A P ) has lower R C F life than double vacuum p rocessed AISI M-50 ( tes t AG and baseline data). However, the difference i s not significant. This appea r s t o be con t r a ry to previous genera l exper ience where VIM-VAR AISI M-50 h a s approximately twice the R C F life of VAR AISI M- 50.

Both gold and ch rome platings w e r e observed to be removed shor t ly a f t e r init ial testing period. F igure 9 shows the plating of untested specimens. A gold plated ba r was nickel plated to p r e s e r v e the plating f o r optical microscopy (F igure 9 -a). Fa i lu re modes in plated spec imens w e r e identical to those of other nonplated specimens. The de t r imenta l effect of chrome plating may be f rnm hard par t ic les generated during the initial testing t ime. P r e s e n t r e su l t s indicate no improvement i n R C F life with ch rome plating. 4gain, the difference i s not s ta t is t ical ly meaningful.

b) AISI 9310

Chemical compositions, heat t r e a t k g proce s s c s and a summary of R C F tes t resu l t s and metal lurgical cha rac t e r i s t i c s for the AISI 9310 t e s t s e r i e s in P h a s e s I , I1 and I11 a r e provided in Tables 4, 5, and 6, respectively. F igure 10 shows corresponding Weibull plots of t e s t resu l t s . B-10 l ives a r e indicated a s a bar cha r t in F igu re 11. w s indicated in Table 5, t e s t s e r i e s AA and baseline tes t w e r e heat t rea ted a t the s a m e t ime under iderkical conditions. The same is t rue for t e s t s e r i e s AQ and AR. Micros t ruc tures for t e s t s e r i e s AQ and AR a r e shown in F igu res 12 and 1 3, respect ively.

Cont rary to Phase I1 study, i t was indicated f rom Weibull ana lys i s of data, the double vacuum processed AISI 931 0 (VIM-VAR, t e s t s e r i e s AR) had a significantly g r e a t e r B-10 life than the single vacuum melted AISI 9310 ( V A k t e s t s e r i e s AQ). However, the data for these two t e s t s e r i e s indicates that the B-10 l ives a r e comparable when the f i r s t five o r s ix e a r l y fa i lures a r e considered for Weibull analysis . (See F igu res 43 and 44 in Appendix D. ) This should be clar i f ied in future s tudies .

Volume percent retained austeni te was varied f r o m 7 . 7 % to 20. 1%. It may be resul tant f rom higher austenitizing t empera tu re s employed (843" C, 857" C (1 550" F, 1575" F)) than recommended hardening t empera - t u r e s by Aerospace industry for AISI 3310 (816°C (1500°Fj).

Higher amount of carbon absorbed in meta l ma t r ix during higher t e m p e r a - t u r e austenitizing r e t a r d s mar tens i t ic t ransformat ion during cooling. This resu l t s i n retaining m o r e austeni te a f te r the t ransformation.

TA

BL

E 4

CH

EM

ICA

L C

OM

PO

SIT

ION

OF

AIS

I 9

31

0

All

oy

ing

Ele

men

t, P

er

ce

nt

by Weight (

Ba

lan

ce F

e)

Te

st

Phase

Se

rie

s

I X

I1

AA

Ba

se-

lin

e

III

AQ

LU

AR

Ma

ter

ials

1

AIS

I 9

31

0

0.0

7

(VA

R)

AIS

I 9

31

0

(VIM

-VA

R)

I 0-1

1

AIS

I 9

31

0

AIS

I 9

31

0

(VIM

-VA

R)

He

at

Tre

ati

ng

Pre

he

at

Ca

rbu

riz

e

Re

he

at

Au

ste

nit

ize

De

ep

F

ree

ze

Te

mp

er

Str

es

s

Re

lle

ve

TA

BL

E 5

HE

AT

TR

EA

TIN

G P

RO

CE

SS

FO

R A

ISI

93

10

Te

st

Se

rie

s X

T

es

t S

eri

es

AA

T

es

t S

eri

es

(V

AR

) (V

IM- V

AR

) B

ase

lin

e

,

92

7°C

1

5 m

inu

tes,

(1

70

0°F

) a

ir

co

ol

to R

T

92

7°C

(1

70

0°

F)

6 h

ou

rs

94

1"C

/96

8'C

I

Sa

me

as

(1

72

5" F

/ 1

77

5"

F)

Te

st

Se

rie

s

12

ho

urs

I

AA

59

3°C

(1

10

0" F

) S

am

e a

s

10

ho

urs

, a

ir

Te

st

Se

rie

s

co

ol

AA

85

7°

C (

15

75

°F

) o

il q

ue

nc

h

85

7°C

(1

57

5'F

) S

am

e a

s

20

min

ute

s,

oil

T

es

t S

eri

es

q

ue

nc

h

AA

-73

°C

(-1

00

°F

) I

-73

°C

(-1

00

°F

) I

Sa

me

as

3

ho

urs

I

3 h

ou

rs

I T

es

tse

rie

s

18

2" C

(3

60

" F

)

18

2'C

(3

60

°F

) 1

ho

ur

1 h

ou

r re

T

es

t S

eri

es

a

s

Te

st

Se

rie

s A

Q

Test

Seri

es

AR

W

AR

) (V

IM - V

AR

)

89

9°C

(1

65

0" F

) S

am

e a

s T

es

t 8 h

ou

rs,

air

co

ol

Se

rie

s A

Q

to R

T

6 4

9°C

(1

20

0" F

) S

am

e a

s T

es

t 2

.5 h

ou

rs,

air

S

eri

es

AQ

c

001

84

3°C

(1

55

0"

F)

Sa

me

as

Te

st

2.5

h

ou

rs,

oil

S

eri

es

AQ

q

ue

nc

h

-84

°C

(-1

20

°F

) S

am

e a

s T

es

t 3

.5

ho

urs

S

eri

es

AQ

17

7'C

(3

50

°F

) Same a

s T

es

t 2

+2

ho

urs

S

eri

es

AQ

17

7°C

(3

50

°F

) S

am

e a

s T

es

t 2

ho

urs

, a

fte

r S

er

J~

s

AQ

fi

nis

h g

rin

din

g I

VAR AISl 9310

(Test Series x)

J

Test Conditions

Smax =

4,826 MPa(700ksi)

Speed =

6.23

ds

ec

(245 in/sec)

Lubricant - M

IL-L-7808

Temperature -

Room-ambient

lo7

lo8

FATIGUE LIFE, STRESS CYCLES

Figure 10.

Fatigue Life Comparison of AISI 9310.

- VAR VIM-VAR

AISI 9310

*Numbers i n percent represent t h e volume percent r e t a i n e d a u s t e n i t e i n t h e c a s e s t r u c t u r e .

11.2% b a s e l i n e

VAR VAR

t I b a s e l i n e

1 M-VAR -- L V I

AISI M-50

Figure 11. B-10 Fat igue L i f e Cornparision of AISI 9310,

No conclurive remarks can be made wlth regards to the effect of retained aurtenite p re r tn t in the c a s e s t ruc ture on RGF. Thia is because of the reaulta f rom Phare KX. However, i t appeara that retained aust tni to mur t exceed 20% to significantly increaae the RCF life in A - S I 9310.

c ) EX00014 (Teat Ser ies AS)

The specific chemical composition for VAR EX00014 (Teet Scriea AS) was:

The heat treating process uacd for VAR EX00014 i s given in Table 7. It was air-hardened a f t e r austenitizing a t 81b0 /82QeC ( I 500'1 1525'C) for 30 minutes. An advantage of air-hardening i s that i t i s l e s s susceptible to distortion or cracking during hear treating t\an oil quench hardening, wtiich i s more typical for case carburized material. This alloy ie said to have greater resistaricc to tempering than s tee ls such a s A I S I 9310 o r AISI 9310 ( + ( 3 0 - ~ S \ ~ C : I . ( ~ '

A sumnrary o i the RCF test resul ts and ~iietallurgical c.v.rliiation is described i n Table 8. Figure 1 4 slro\vs case .\mi core n~icrozt r \ rc tures of the VAR i:S00014 test apccinwns. It i s indicated w.rder tllc present exper in~enta l conditions that R C F pperior~nanct* 01' \'t\I', E ~ S O O O I I i s equivalent to t h o ~ e oi V A R A IS l "310 and of V I M - YAK AIS I M - 50.

He at Test hlcltinp , Nurnbcr Ser ies Prtbcess (:ant ract Plrn LIP

Nut known ?' A h l r - I

2 V t W H A C \:A R I1

2 V ~ ? 7 9 A E \'A R 11

2V6978 A F YAR I1

3501 7 AIi A hi* 111

b

+Air hlelted

TABLE 7

H E A T TREATING PROCESS FOR VAR EX00014

(Test Series AS)

1 ) Preheat to 593" C (1 100" F) for 1 hour, air cool.

2 ) Carburize at 871 -927OC (1600 1700" F), furnace

cool to 816°C-843°C (1500-1550°F), air cool to

room temperature .

3) Austenitize at 816-829°C (1 500-1 525°F) for 30

minutes, air cool to room temperature.

4) Deep freeze at - 7 3 ° C (-100°F) for 1 hour.

5 ) Double-temper at 143°C 1300" F) for 2 hours each.

TA

BL

E 8

SU

MM

AR

Y O

F R

CF

TE

ST

RE

SU

LT

S A

ND

ME

TA

LL

UR

GIC

AL

CH

AR

AC

TE

RIS

TIC

S O

F E

X0

00

14

Ma

teri

als

EX

00

01

4 {

VA

R)

Te

st

Co

nd

itio

ns:

Ma

x.

Hz

Str

es

s (

S

):

ma

x

Sp

ee

d:

Lu

bri

ca

nt:

Te

mp

erk

ture

:

I Ba

se-

lin

e

Ba

se-

lin

e

AIS

I 9

31

0 (

VA

R)

AIS

I M

-50

(V

IM-V

AR

)

(a)

- Number o

f fa

ilu

res

ou

t o

f to

tal

nu

mb

er

of

test

s.

(b)

- No

t d

ete

cte

d.

4,8

26

MP

a (

70

0 k

si)

6.2

3 m

/se

c (

24

5 i

n/s

ec

)

MIL

-L-7

80

8

Ro

om

-am

bie

nt

Su

rfa

ce

Ha

rdn

ess

, H

RC

60

.6

61

.4

B-1

0

Lif

e

, x lo

6 C

yc

les

3.2

7

4.1

8

Re

tain

ed

Vo

l. 7.0

B-5

0

Lif

e

, x

lo

6

Cy

cle

s

13

.85

9.4

3

allu

re'^

' In

de

x

10

/10

10

/10

We

ibu

ll

Slo

pe

1.3

1

2.3

1

Eff

ec

tiv

e

Ca

se

Dep

th,

mm

(in

. )

0.5

1 (

0.0

20

)

0.8

4(0

.03

3)

TAB1 5 9 -- CHEMISTRY SPFSIFICL\TION - FOR CBSb00

Elements

Carbon

Manganese

Sulfur

Phosphorus

Silicon

Chromium

Molybdenum

Iron

Weight Percent - 0 .17 -0 .22

0 . 4 0 - 0 . 7 0

0 .25 Max.

0.025 Max.

0 . 9 0 - 1 . 2 5

1 .25 -1 .65

0 . 9 0 - 1 . 1 0

Balance

TABLE 10

CHEMICAL COMPOSITION OF C BS6OO

(In Weight Percent)

Element

Carbon

Mangane se

Phosphorus

Sulfur

Silicon

Chromium

Nickel

Molybdenum

Copper

Iron

Test Series AD, AE & A F

Test Ser ies AH

. . - .- . --.- -

0. l ?

0.61

0.007

0.014

1 . 0 5

1.50

0.18

0.94

-

Balance

Pre

hea

t

Ca

rbu

rize

I

Tem

per

I

Au

sten

itiz

e

1 Dee

p F

re

ez

e

Tem

per

-i-

TABLE 1

1 -

HE

AT

TR

EA

TIN

G P

RO

CE

SS

FO

R C

BSb

OO

I

Ph

ase

I

1 P

ha

se 11

I P

ha

se I

1 I

Ph

ase

11

Ph

ase

3I.I

v

AD

AE

I AF

1 AH

I I

I ~

~

---.-

- -

-. .

1

- - . , - - -

- .. .

. . - .

- -- -

- - - .

-

- ---. -

J 5

93

°C 1

11O

O0F

) - -

- -

- -

5

93

'C

(1 1

00

- F)

30 m

inu

tes

2 h

curs

-

92

7"

C 1

17P

Oa F

) 9

41

" /0

68

"C

S

am

ea

sA

D

Sa

me

as

AD

9

27

'C(1

70

0'F

) 6

ho

urs

(1

72

5O

I17

75

"F

) o

il q

uen

ch

13

ho

urs

, o

il

- -

62

10

~

(1 1

50

0)

Same a

s A

D

Sa

me

as

AD

5

93

"/6

49

'C

(11

00

7

4 h

ou

rs,

air

12

00'

F)

4 h

our

I co

ol

85

7"

C[1

57

5"

F)

82

4*

/84

3"

C

Sa

me as A

D

Sa

me

as

AD

8

29

'/8

43

'C

4525

'1

oil

qu

ench

(1

52

5"

/ 1

55

0"

I 155

0.F

) 2

5 m

inu

teq

in

sa

lt 3

0 oil

qu

ench

m

inu

tes,

cil

q

uen

ch

-73

°C (

-10

0°F

) - -

- -

-7

3'C

(-1

00

'F)

- - 3

ho

urs

1

hou

r

18

Z°C

136

0"R

I 18

2"

C (

36

0°F

) 3

16

" C

(6

00

°F)

Sa

me

as

AE

I S

am

e as A

E

1 h

our

2+

2 h

ou

rs

2i2

ho

urs

The chemical compositions for fihase I11 CBS600 ( t e s t s e r i e s AH) and other tes t s e r i e s for CBS600 a r e given in Table 10. Heat t reat ing p r o c e s s e s used for CBS600 a r e summarized in Table 11. A summary of RCF Lest resul t s and meta l lurgica l analyses on CRS600 a r e given in Tables 1 2 and 13, respectively, Corresponding Weibull plots including VAR AISI 931 0 and VIM-VAR AISI M - 50 a r e shown in Figure 15. B-10 l ives a r e a l so plotted a s a ba r c h a r t in Figure 16.

Optical mic ros t ruc tu re of t e s t s e r i e s A14 is shown in F igures 17 2nd 18. Tes t s e r i e s A H was found to have nonuniform, abnormal mic ros t ruc t \ l r e with c o a r s e g ra jn s i ze in the co re . P re fe ren t i a l etching of c a s e m i c r o - s t ruc tu re was observed to occur a s indicated by the light and da rk a r e a s in Figures 17 and 18. This nlay be due to some deviation f rom the specified heat t rea tment p r o c e d u r e . ( l l ) The deviation appears to be a shor t hold t ime ( l e s s than five minutes) a t austenitizing tempera ture af ter slow cooling f rom carburizing. The c a s e mic ros t ruc tu re observed in Figures 17-a and 18-a may have been from the incomplete austenitization of pearl i te . The pearl i te , an aggregate nf f e r r i t e and spherodized ca rb ides , formed during slow cooling af ter carburizing star t ing f rom the grriin boundaries. At the same t ime, blocky fe r r i t e , a s shown in F igures 1 7-b and 18-b, formed a t the gra in boundaries. The poor fatigue life observed in tes t s e r i e s AH may be attributed to the a k o r m a l m i c r o - s t ruc ture .

Resul ts from the Phase I and 11, previously reported in Reference ( 5 ) , indicated no significant effects on R C F performance with different tempering t empera tu res and with the use of a subzero t rea tment . The p resen t resul t s suggest that the rolling contact fatigue performance of CBSbOO alloy is equivalent to that of VAR AISI 9310 o r that of VIhI-VAI; AISI M - 560

e EX00053 (Tes t Se r i e s AT)

This experimental alloy, EXOOOq3 for tes t s e r i e s A T , has the following chemical specificc::ion:

Elements

C Mn S i C: r Ni M o Cu v E'c

W e i g h t n t

0.10 0. 35 1.00 1.00 2.00 3. 25 2.00 0. 10 13.3 I.

Specific chemical compoaition used for t e s t s e r i e s A T is given in Table 14. Heat t reat ing procedure treed for t e s t s e r i e ~ A T in this study, is de x r i b e d in Table 15. Tes t s p e c i m e n ~ were audtenitized a t 91 3.C (1 67 S e F ) and t double- tempered a t 177" C ( 3 5 0 " F). However, manu- h c t u r s r l e dat8'S showed that EX00053 cirri be tempered a t 31heC (600. F) to have HRC 61 c a s e hardness and t:RC 35 c o r e hardness a f t e r carburizing. Rolling contact fatigue t e s t data a r e included in Appendix C. The t e s t r e su l t s and metal lurgical analyses a r e aummarizec! in Table 16 where VAR AISI 931 0 and VIM- VAR AISI M-50 data a r e included for comparison. Optical nlic rographs showing c a s e and core mic ro - s t ruc ture8 a r e ahown in Figure 19. Smal l spher ica l carbides a r e seen in the c a s e n~ ic ros t r t l c tu re .

P r e s e n t resul t s indicate that R C F strength of VAR EX00053 i s in fe r io r to VAR AISI 9310 and VIM-VAR AISI M-50. However, the difference ie conside red stat is t ic ally insignificant.

f ) CBSlOOOM ( T e s t Se r i e s AJ)

CBS1000M was developed for bearing and gear applici-ttions a t o r up to 31 6.C (600' F). (8) Chemical conipooitions for C: BSI DOOM, inc 1ud;ng P h a s e s I and I1 ( tes t s e r i e s z , A D and A C ) 3re given in Table 17. Heat t reat ing procedures employed for C13SIC)C)Oh~t tes t specimens a r e described in Table 18. Specimens for tes t s e r i e s z , AC: a l ~ d A1 were deep-frozen af ter being austenGtized during heat t reat ing while tes t s e r i e s A B specimens we r e not.

Table 19 s u n ~ n l a r i z e s the resul t s of R C I ? test..; and n~eta l l i~rgic ,a l an,llyses of CBS1000M. Microotructures for test s e r i e s A1 (Phase 111) a r e shtnvn in Figure 20. Core n ~ i c r o s t r u c t u r e appenrs c-onrse. Rctnint*d a t l s l e t ~ i t ~ was lound to be very lo\\. i n the c.lac s t ruc ture fc>r ,111 test sc5ri1 s ( I t - ~ a

than 2",:1). It \\as a l so t'otind th.~t test sc r ips 7. s p e c i n ~ r n s had ;I ~io :~ur~ i io r tn c a s e depth which vr.ricd f r o m 0. 13 mtil(0. 01 7 ' ' ) t o 0. 70 mtir(O. 030''). Case hardness was .11~13 varied f r o l i ~ IlRC $ 3 : 1 1 , .~ccorclitlgly. Therefore , i t was not considered for ~.ouc.lusi\*c evaluation. Test rzsnl t ; a r e sho\vn in Figure 21 where the d,ltn for VIht -VAR AISI hl - 5 0 and t ' A R AISI 931 0 a r c included for r.oti~pnrison. H - 10 Ii\.ea a r c ; i Is i~ S~ICW\.II a s a bar cha r t in Figure 2 2 . It \vas a lso iountl that 1100°C' (201.2" F1 austenitizing and 5-40" C ( 1001)" E') tcmpc ritq: cyc l c s in\.a r i a l ly prcducc the c a s e s t ruc tu re with mininial retainccl a u n t * - ~ i t c (2";11. l?eep irce7ing cycle during hedt treating docs !lot nppchar t o in1prt)ve I . l r degrade HCF perfornmncc of C BS1000hl.

TABLE: 1 5

HEAT TREATING PROCESS FOR VAR EX00053

(Test Series A?')

1 ) Preheat to 593OC ( 1 100°F) for 1 hour,

a ir cool.

2) Carburize at 871" 1927°C (1600" /1700° F),

a ir cool to room temperature.

3) Austenitize at 91 3°C ( 1 675°F) for 30 minates

in a protective atmosphere and oil quench.

4) Deep freeze at -73*C (-10O4F) for 1 hour.

TA

BL

E 1

6

VD

ME

TA

LL

UR

G

I O

F R

CF

TE

ST

KESI

ICA

L C

HA

RA

CT

ER

IST

ICS

OF

E

Te

st M

ate

ria

ls

1

Ba

se-

AiS

I 9

31

0

4.1

8

9.4

3

2.3

1

1C/

10

0

.84

(0

.03

3)

61

.4

38

.0

11

.2

lin

e (V

AR

)

Fa

se-

AIS

I M

-50

3

.80

6

.30

3

.30

2

50

/25

0

--

63

.0

- -

N. D. (b)

lin

e (V

IM-V

AR

)

(a)

- N

um

ber

of

fail

ure

s o

ut

of

tota

l n

um

ber

of

test

s.

(b) -

No

t d

etec

ted

.

Te

st C

on

dit

ion

s

S

4,8

26

MP

a (

70

0 k

si)

ma

x'

Sp

eed

: 6

.23

mls

ec

(2

45

in

/se

c)

Lu

bri

can

t:

MIL

-L-7

80

8

Tem

per

atu

re:

Ro

om

-am

bie

nt

TABLE 1

7

CHEMICAL COMPOSITION OF C

BS

1 COOM

TA

BL

E 1

8

HE

AT

TREATING P

RO

CE

SS

FO

R C

BS

lOO

OM

Hea

t P

ha

se L

rre

ati

ng

1 gr?e

s

z P

ha

se II

I P

ha

se 11

Phase III

I AB

AC

I

I I

ho

urs

I

1 h

ou

r,

air

co

ol

I I

ho

ur

in v

acu

um

, 2

ho

urr

in

air

in

ert

ga

s q

uen

ch

I C

arb

uri

ze

9

27

'C

(17

00

" F

) 9

54

'C

(17

50

°F)

941'C

(1

72

5.F

) 927'C

(1

70

0'F

) 6

ho

urs

1

1 h

ou

rs

10

ho

urs

, d

rop

2 h

ou

rs

to 8

16

'C

(1 5O

O'F

) o

il q

uen

ch

Re

he

at

- Au

sten

- it

ize

78

8°C

(1

450"

FI

30 m

inu

tes.

ra

pid

in

c re

ae

e

to 1

10

7°C

(2

025' F)

I 1

10

7°C

(2

02

5'F

) o

il q

uen

ch

!

10

93

'C

(20

00

" F

) 1

09

3'C

(2

0@

Om

F

) sa

lt q

uen

ch 5

52

-C

(10

25

"F),

air

788'C

-843.C

(1

45

0°F

-15

50

'F)

in v

acu

um

fu

mt

15

min

ute

s

11

07

'C

(20

25

-F)

in v

acu

um

15

minutes, g

as quench

I I

I co

ol

I T

em

pe

r . -

- -

371.

C

(70

0' F)

1 h

ou

r I

I

I

Dee

p

Fre

ez

e

Te

mp

er

-73'C

(-

lCO

'F)

3 h

ou

rs

56

6°C

(1

05

0°F

) 2

+2

+2

ho

urs

- -

538'C

(1

00

0' E')

2+

2+

2 h

ou

rs

-73

'C

(-1

00

'F)

1 h

ou

r

53

8°C

(1

00

0°F

) 2

+2

+2

ho

ur

B

-73'C

- -R

4*C

(-

IOO

'F-

-12

3-F

) 1 h

ou

r

538" C

(1

000.

F)

2+2+

2 h

ou

r s

TA

BL

E 1

9

SU

MM

AR

O

F RCF T

ES

T RESULTS A

ND

ME

TA

LL

UR

GIC

AL

CH

AR

AC

TE

RIS

TIC

S O

F C

BSI

OO

OM

Eff

ecti

ve

Ca

se

Co

re

Ret

ain

ed

Wei

bu

ll

~a

ilu

re

'~' C

as

e D

epth

H

ar

dn

ess

H

ard

nes

s A

ust

enit

e S

lop

e In

de

x

mm

(in

) H

RC

H

RC

Vol.

%

----

----

...

. -

---

. --

---

- 2

.73

2

0/2

0

0.4

3 (

0.0

17

)-

59

-61

4

5.0

N. D.

(c 1

B-

50

Lif

e ,

xi0

C

yc

les

(a)

- N

um

ber

of

fail

ure

s ou

t o

f to

tal

nu

mb

er o

f te

sts.

(b)

- No

nu

nif

orm

an

d i

nsu

ffic

ien

t c

ase

dep

th.

(c) - N

ot

det

ecte

d.

Te

st C

on

dit

ion

s

S

(Ma

x.

Hz

Str

ess

):

4.8

26

MP

a (

70

0 k

si)

ma

x

Sp

eed

: 6

.23

rn

laec

(2

45

m/a

ec

)

Lu

bri

can

t:

MIL

-L -7

80

8

Tem

per

atu

re : R

oo

m-a

mb

ien

t

Test Conditions

Smax =

4,826 MPa(700ksi)

Speed =

6.23 dsec(245 in/sec)

Lubricant - M

IL-L

-780

8 Temperature - R

oom-ambient

FA

TIG

UE

L

IFE

, STRESS C

YC

LE

S

Figure

21

. Fatigue Life Comparison of CBS 1000h1

ORIGINAL PAGE IS OF POOR QUALm

tha t VAR CBSlOOOM is i n f e r i o r to both VIM-VAR AISI M- 50 and t o VAR AISI 931 0. However , the di f ference is s ta t i s t i ca l ly insignificant.

Metal lurgical ly , Vasco X-2 is s i m i l a r t o CBS1000M. E o t i ~ CBSlOOOM and Vasco X-2 have c a s e m i c r o s t r u c t u r e s i m i l a r t o those of high speed tool s t e e l s . Chemica l composi t ions of Vasco X-2 used in these inves t i - gat ions a r e given in Table 20. Table 21 s u m m a r i z e s heat t r ea t ing p r o c e s s e s u s e d fo r a l l t e s t s e r i e s f o r Vasco X-2. Austenit izing t e m p e r a t u r e w a s 101O0C (1850" F) and t emper ing t e m p e r a t u r e w a s 316°C (600" F) excep t f o r t e s t s e r i e s AK w h e r e 510°C (950" F) t e m p r ing w a s employed. To find the effect of shot peening on R C F , t e s t s e r i e s AM w a s shot peened a f t e r being lleat t r ea ted the s a m e a s t e s t s e r i e s AL.

Table 22 s u m m a r i z e s R C F t e s t r e s u l t s and meta l lu rg ica l c h a r a c t e r i s t i c s of Vasco X-2. Weibull plots of R C F da ta f o r VAR Vasco X-2 a r e shown in F i g u r e 23 w h e r e the data o i VIM-VAR AISI M-50 and VAR AISI 9310 a r e included f o r compar i son . B-10 l i v e s a r e a l s o shown a s a b a r c h a r t in F i g u r e 24. M i c r o s t r u c t u r e s of e a c h t e s t s e r i e s f o r Vasco X-2 a r e p resen ted in F i g u r e s 25 through 28.

Volume p e r c e n t of re ta ined austeni te was v a r i e d f r o m 0 to 2270, being m o r e than f o r the c a s e of CBS1000M. The r e a s o n m a y be a t t r ibuted to the lower t emper ing t e m p e r a t u r e s used for Vasco X-2. It i s a l s o shown that R C F life w a s i l lcreased when re ta ined aus ten i t e i s i n c r e a s e d . It is a l s o cons i s ten t with the g e n e r a l obse rva t ion in thac re ta ined aus ten i t e i s l e s s with spec imens t empered a t h igher t e m p e r a t u r e s ( c o m p a r e t e s t s e r i e s A J with A K ) .

R C F p e r f o r m a n c e of Vasco X-2 i s considered to be in fe r io r o r equa l t o VIM-VAR AISI M-50 and VAR AISI 9310. I t i s in te res t ing to note that when re ta ined austeni te in the c a s e s t r u c t u r e of Vasco X-2 i s min imal , the R C F per fo rmance becomes c o m p a r a b l e to that of CBS1000M.

The shot peening left the bar su r face with a rough, 1 .27 ym (5Opin) r m s finish. A f inal gr ind was used. removing about 0.025 mm (0.001 in) . to get the b a r s u r f a c e within the finish fpecification. C i r c u m f e r e n t i a l r es idua l s t r e s s d is t r ibut ion in Vasco X-2 ( t e s t se r i es A L and AM) i s given in Table 23 and plotted in F i g l x e 29. In F i g u r e 29, the depth of m a x i m u m s h e a r s t r e s s (0.007 in ) i s indicated where c o m p r e s s i v e s t r e s s i s -827 M P a ( -120 k s i ) f o r shot peened and -207 M P a ( - 3 0 k s i ) f o r nonshot peened. Unexpectedly, i t a p p e a r s that shot peening i s not

TA

BL

E 20

CHEMICAL COMPOSITION OF VASCO X-2

All

oy

ing

Ele

men

t.

Pe

rc

en

t b

y W

eig

ht (Balance F

e)

Te

st

Hea

t S

er

ies

N

um

be

r

C

Si

Mn

S

P

W

C

r

V

TA

BL

E 2

1

HE

AT

TR

EA

TIN

G P

RO

CE

SS

FO

R V

AS

CO

X-2

Heat

Te

st S

eri

es

AJ

A

h

-

I

tl Ca

rbu

riz

e

10

1O

0C

(18

50

'Fl

2-3

ho

urs

in a

ir

Heat

to 8

43.C

(1

550'

1:) in

air

an

d e

qu

ali

ze,

heat

to 1

01

0°C

(1

85O

.F)

in a

ir,

hold

30 m

in.,

a

ir c

oo

l

95

4'C

(1

75

0" F)

7 h

ou

rs i

n e

nd

o-

the

rmic

gas

Sam

e a

s T

est

S

eri

es A

J.

- 9

27

'C

(17

00

' F

) fo

r 1

.75

hrs

, o

il a

ilen

ch from 7

88

'C

(14

50

T),

sn

ap

te

mp

er

at

14

9'C

(3

00

.F)

2 hourr

Pre

he

at

to 8

1 6' C

(1

50

0aF

),

10

IO°C

(1

85

0°F

),

10

min

.

- -

Sam

e a

s T

est

S

eri

es A

J,

Au

sten

- it

ize t-

10

10

'C (

18

50

°F)

in

pro

tecti

ve a

tmo

s -

Sa

me

as

Te

st

ph

ere

I h

ou

r,

oil

S

eri

es A

J.

qu

ench

-73

°C (

-10

0°F

) S

am

e a

s T

est

3

ho

urs

S

eri

es A

J.

10

IOeC

(1 8

50

-F)

1 h

ou

r,

oil

q

uen

ch

Fre

ez

e

Te

mp

er

31

6°C

(6

00

-F)

2+

2+

L

ho

urs

Te

mp

er

316'C

T

em

pe

r 5

10

'C

(60

0' F) 2

+2

+2

(9

50

'F)

2+

2+

2

ho

urs

h

ou

rs

Tem

per

Peen

Temper 3

16

-C (

60

0.F

) 2

+2

hrs

.

I-'

Sh

ot Peened 7

TA

BL

E 2

2-

SUM

M-Z

RY

OF

RC

F TEST RESULTS A

ND

ME

TA

LL

UR

GIC

AL

CH

AR

AC

TE

RIS

TIC

S O

F V

AS

CO

X-2

(a) -

Su

mb

er

01

fai1

ul.

e~

on

t of

to

tal

nu

mb

er

at

test

s.

ib\

- Not

de

tec

ted

. Test C

orx

htm

ns

S

= 4

,82

6 M

Pa

(7

00

ksi

) ~

pe

%

= 6

.23

n>

/se

c (2

45

in

lse

c)

tem

pe

r

AJ

2

.88

i5

1

.73

1

0/1

0

,0.7

6(0

.03

0)

61

.8

42

.0

5.0

1 ,

, P

ha

se

111

316'C

te

mp

er

AK

1

. 5

6

I. 9

3

2.0

3

10

/10

0

.7(1

(o.O

30

) 6

0.5

4

6.0

N

. D

.(~

' P

ha

se

III

510'C

te

mp

er

AL

3

.63

1

2.2

4

I. 5

5

10

/10

0

.64

(0

.92

5)

60

.6

43

.0

11

.0

Ph

as

e 311

316'C

te

mp

er

AM

2

.30

4

.42

I

2-8

4

' 3

3

0.6

4

(0.0

25

) 6

2.4

4

3.0

1

1.0

P

ha

se

IU

316'C

te

mp

er.

sh

ot

peen

ed

B-50

Lif

e

, x

lo

6

Cy

cle

s

15

.13

t

Te

st

Se

rie

s

b

Lu

bri

ca

nt:

M

IL-L

-78

08

B- LO

Lif

e

. x lo

6

Cy

cle

s

6.

31

Weib

ull

S

lop

e

2.1

6

Te

mp

era

ture

: R

oo

rn-a

mb

ien

t

Re

tain

ed

A

ust

en

ite

V

ol.

%

22

.0

Re

ma

rks

Ph

ase

I

31 6

'C

Ca

se

H

ard

ne

ss

HR

C

43

.0

~a

ilu

re

(~

' ln

dex

20

/20

Eff

ecti

ve

Ca

se

Dep

th

mn

, (i

n)

0.8

9

(0.0

35

)

I

Core

Ha

rdn

ess

HR

C

60

.0

TABLE 23 - CIRCUMFERENTIAL RESIDUAL STRESS

DISTRIBUTIONS IN AS-RECEIVED VASCO X-2 SPECIMENS

Depth Below Surface ( x 1 ~ - 3 in)

(By X-ray Technique)

Re sidl Test Ser ies A L

MPa (ksi)

.1 S tress Test Ser ies AM**

MPa (ksi)

*Greater than -827 MFa ( -120 ksi)

**(0.001") 0 . 2 5 4 p was removed from the surface by final grinding before testing.

Test Conditions

Smax

=

4,826 M

Pa(

7OO

ksi

) Speed =

6.2

3 d

se

c(2

45

in/sec)

Lu b

ri cant - M

IL-L

-780

8 Temperature -

Room-ambient

lo7

lo8

FATIGUE LIFE,

STR

ESS

CYCLES

Fig

ure

23.

Fatigue Life Comparison of Vasco

X-2

.

I Depth Below Surface

Tes t S e r i e s AM shot -peened

I I 1 Depth o f Maximum Shear S t r e s s

Tes t S e r i e s AL

Figure 29. Circumferential Residual S t r e s s a s a Function o f Depth Below Surface of Vascc X-2 Specimens.

beneficial to RGF performance. The r ea son for this i s not known a t the p re sen t t ime.

All previous investigations with the exception of Kepple and Mattson's study(12) show that camp-essive s t r e s s e s introduced e i t he r mechanical ly o r metal lurgical ly processed (i. e., c a s e hardening) a r e beneficial t o roll ing contact fatigue l ives. F o r a detailed l i t e r a tu re review, read Reference (1 3). However, Kepple and -Mattson reported that compress ive s t r e s s e s induced by in te r fe rence f i t s did not show any improvement on rolling e l emen t fatigue life, I t is interest ing to note that a l l s tudies showed the de t r imenta l effect of tensi le s t r e s s e s t o roli ing contact fatigue life performance.

VascoMax 350 and Vasco Mat r ix I1

Chemical compositions of VAR VascoMax 350 ( t e s t s e r i e s AN) and VAR Vasco Matr ix 11 ( tes t s e r i e s w and AO) a r e descr ibed in Table 24. Table 25 summar i ze s the heat t reat ing procedures used in this investigation. VAR VascoMax 350 ( tes t s e r i e s AN) was aged a t 488'-504°C (910" -940°F) t o have HRC 5 9 , 5 through precipitation hardening in mar t ens i t e m a t r i x s t ruc ture . VAR Vasco Matr ix I1 was through-hardened in a s i m i l a r manner to other high strength tool s tee l s such a s AISI M-50.

Table 26 summar i ze s RCF t e s t s and metal lurgical ana lyses on these alloys. Micros t ruc tures a r e shown in F igu re s 30 and 31. Volume percent retained austenite was measured to be low by X- ray diffraction technique. Weibull plots of tes ted ma te r i a l s a r e given in F igure 22.

Based on the p re sen t r e su l t s , i t is concluded that VAR VascoMax 350 is infer ior to VIM-VAR AISI M-50 or VAR AISI 9310. This may be due t o the par t ly low hardness inherent in this mater ia l , but the magnitude of high difference is probably g r e a t e r than could be expected for ha rdnes s alone. It i s a l so shown that VAK Vasco Matr ix I1 i s equivalent to VIM- VAR AISI M - 50 and VAR AISI 931 0 in R C F life strevlgth.

TA

BL

E 2

4

CH

EM

ICA

L C

OM

PO

SIT

IOIJ

OF

VA

SC

OM

AX

350 AND V

AS

CO

MA

TR

IX IZ

HE

AT

TR

EA

TIN

G P

RO

CE

SS

FOR V

AS

CO

MA

X 3

50

AN

D V

AS

CO

MATRIX II

I P

ha

se

III

H

ea

t I

VA

RV

as

co

Ma

x3

50

T

rea

tin

g

1 (T

es

t S

eri

es

AN

)

Phase I

P

ha

se

IIi

VA

R V

asc

o M

atr

ix II

VA

R V

asc

o M

atr

ix 11

(Te

st

Se

rie

s W)

(Te

st

Seri

es A

01

-

Pre

he

at

59

9°C

(1

65

0" F

) 3

0 m

inu

tes,

a

ir

co

ol

to R

T

Au

s te

nit

ize

1

10

4" C

(2

02

0" F

) q

ue

nc

h i

n s

alt

at

53

8°C

(lO

OO

°F),

a

ir c

oo

l to

RT

11

16

°C (

20

40

°F

) for 1

5

min

ute

s,

qu

en

ch

in

sa

lt

ba

th a

t 607°C (

1 lZ

5"

F),

air cool t

o R

T

- A

ge

ha

rde

n t

o H

RC

5

10

°C (

95

3°F

) 5

38

°C (

10

00

°F

) 2

+1

hours

59

-60

for 3 h

ou

rs a

t 2 t2 h

ou

rs

48

8-5

04

" C

(9

10

-94

0°F

).

Te

mp

er

air

co

ol

to R

T

' I

I

TABLE 2

6

SU

MM

AR

Y OF R

CF

TEST RESULTS A

ND

ME

TA

LL

UR

GIC

AL

CHARACTERISTICS O

F VASCOMAX 350 AND

VASCO M

AT

RIX

II

B-1

0

B-5

0

Lif

e

Lif

e

6 6

Re

tain

ed

T

es

t T

es

t ,

x1

0

, x

10

W

eib

ull

~

ail

ure

!~)

Ha

rdn

es

s

Au

sten

ite

Ph

as

e

Se

rie

s

Ma

teri

als

C

yc

les

Cy

cle

s S

lop

e

Ind

ex

HRC

Vo

l.

TO

Uil

AN

V

asc

oM

ax

0

.14

0

.77

1

.09

1

0/1

0

59

.5

N.

D. (b)

35

0 (

VA

R)

I #

Va

sco

3

.60

8

.03

2

.35

2

0!2

0

62

.6

1.2

M

atr

ix I

1

iVA

R)

III

A0

V

asc

o

3.3

1

13

.89

1

.31

1

0/1

0

61.8

N. D

. M

atr

ix I1

WA

R)

(a)

- Number o

f fa

ilu

res

ou

t o

f to

tal

nu

mb

er

of t

es

ts.

[ b)

- N

ot

de

tec

ted

.

"?st

C

on

dit

ion

s

S m

ax

= 4

,82

6 M

Pa

(7

00

ksi

)

Sp

ee

d =

6.2

3

m/s

ec

(2

45

in

/se

c)

Lu

bri

ca

nt:

MIL

-L -7

80

8

Te

mp

era

ture

: R

oo

m-a

mb

ien

t

FATIGUE L

IFE

, ST

RE

SS

CY

CLE

S

Fig

ur

e 32.

Fatigue Life Comparison of VascoMax 350 and Vaco Matrix 11.

IV. SUMMARY AND CONCLUSIONS

Rolling e l e m e n t fatigue l i ves of nine a l loys w e r e evaluated in the Gene ra l E l e c t r i c Rolling Contact (NC) r igs . Test condit ions used in the GE RC r i g s with cy l indr ica l spec imens included a kier tzian s t r e s s a t 4 ,826 MPa (709 ksi) , a rolling speed of 6.23 m l s e c (215 i n l s e c . ). T e s t s w e r e run with a Type I o i l (MIL-L-7808G) a t room t empera tu re . Meta l lurg ica l ana lyses w e r e m a d e before and a f t e r the RC: rig t e s t s . T e s t da ta w e r e s ta t i s t ica l ly analyzed using the Weibull d i s t r ibu t ion function. B-10 l i ves (10% fa i lure r a t e ) of a l l oys w e r e compared v e r s u s r e f e r e n c e a l loys , VIM-VAR AISI M-50 and VAR AISI 9310.

The a l loys studied w e r e s ix c a s e ca rbu r i z ing a l loys (AISI 3310, CBS600, CRSlOOOM, EX00014, Vasco X-2 and EX00053) and t h r e e through-hardening a l loys (AISI M-50, VascoMax 350 and Vasco Mat .x 11). The ef fec ts of different heat t r ea tmen t s , vaciinm melt ing p r o c e s s e s , shot peening, dold plat ing and c h r o m e plating on R C F p e r f o r m a n c e w e r e s tudied with se lec ted al loys.

All a l l oys except VascoMax 350 invest igated in th i s final phase of the study ( P h a s e 111) showed R C F p e r f a r n ~ a n c e in fe r io r o r equivalent to that of AISI 931 0 and of AISI M- 50. I Iowever , the d i f fe rences w e r e not s ta t i s t ica l ly significant. VascoMax 350 showed v e r y poor R C F life.

Double vac u i ~ m p r o c e s sing (VIM - V A R ) was found to i n ~ p r o v e RC: E' pe r fo rmance o v e r that of single vacuuni p roces s ing (VAR) in both AISI M-50 a ld AJSI 0310. but in this study the it!\provernents u,ere not s ta t i s t ica l ly significant.

The effects of different temper ing t c n ~ p e r a t t ~ r r s employed and t h e introduct ion of f reezing cyc le s did not significantly affcct HCF' life of Vasco X-2.

Shot peening the su r f ace o f V R S C O X - 2 test b a r s failed to sllc .v the improvemen t in RCF' lift* cxpectcti tiuc to beneficial s i ibsurface c o m p r e s s i v e res idua l s tress .

Neither golcl nor c h r o n ~ r plating wcrc8 Iwnefit.ial to RCF p e r f i ) r n ~ a n c e of VIM-VAR AISI hi-50. Cllromc* plating giivc 1ivc.s l e s s t ha:r thc basel ine V I M - V A R M - 5 0 , but thc d i f i c r cnce \vas not statistic-ally s;gnificnnt.

t. REFERENCES

E. N. B a m b e r g e r , e t a l , "Life Adjustment F a c t o r s f o r Bal l and Ro l l e r Bea r ings - a n Engineer ing Design Guide", AShlE, New York, 1971.

R , J. P a r k e r and E. V. Za re t sky , "Rolling E lemen t Fa t igue L i v e s of Tllrough-IIardened Bearing Mater ials" , T r a n s . ASME. J . Lub. "ech . , Vol. 94, S e r i e s F, 1972, pp 165-173.

E. N. B a m b e r g e r and R. J. P a r k e r , "Effect of Wall Th ickness and Mate r i a l on F l e x u r a l Fat igue of Hallow Rolling Elements" , J. Lub. Tech. , ASME T r a n s . , Vol. 100, S e r i e s F, No. 1, J a n u a r y 1978, pp 39-46.

E . N. B a m b e r g e r , "Investigation of Hollow Rolling E l e m e n t Fa t igue Charac t e r i s t i c s " , Cont rac t NAS3- 13302, I n t e r i m Eng ineering Repor t , Apr i l 20, 1972.

A. H. Nahm, "Rolling E l e m e n t Fat igue Test ing of G e a r Mater ials" . In t e r im Repor t , GE Repor t R78AEGZ89, NASA CR - 13 541 1, A p r i l 1 , 1978.

E. N. Bamberge r , "The Effect o f Ausforming on the Rolling Contact Fa t igue Life of a Typical Bearing Steel", J. Lub. Tech . , ASME T r a n s . , Vol. 89, S e r i e s F, N o . 1 , J anua ry 1967. pp 63-75.

H. S. Cheng, "A Numer i ca l Solution of the Elastohydrodynamic F i l m Thickness in an El l ipt ical Contclct", 'Trans. ASME, J. Lub. Tech . , Vol. 92f, 1970, pp 1 5 5 - 162.

L . G. Johnson, "The Sta t i s t ica l T rea tmen t of F a t i g u e E x p e r i m e n t s t t , E l s e v i e r Pubi ishing Company, 19b4.

V. REFERENCES (Continued)

9. T. V. Phi l ips , C a r p e n t e r Technology Corp. , P r i v a t e Communicat ion.

10. C. F. Ja tcaak , "Specialty Ca rbur i z ing S tee l s fo r Eleva ted T e m p e r a t u r e Service", Metal P r o g r e s s , Apr i l 1978, pp 70 78.

11. C. F. Ja tczak , The Timken Company, P r i v a t e Communicat ion, 1978.

12. R. J. P a r k e r and E. V. Za re t sky , "Effect of Residual S t r e s s e s Induced by P r e s t r e s s i n g on Rolling E lemen t Fa t igue Life", NASA TN D-6995, October 1972.

13. R. K. Kepple and R. L. Mattson, "Rolling E l e m e n t Fa t igue and Macro res idua l S t ress" , J. Lub. Tech., ASME Trans., Vol. 92, No. 1 , J a n u a r y 1970, pp 76-82.

TA

BL

E 2

7

CH

EM

ICA

L C

OM

PO

SIT

ION

OF

TE

ST

MA

TE

RIA

LS

FO

R PHASX UI

1 M

ate

ria

l 1

Te

st

(Mel

tin

g

I A

llo

yin

g E

lem

en

t,

Pe

rce

nt.

by W

eig

ht

(Bal

anc

Se

rie

s

Pro

ce

ss

) IS

i I

M~

IS

I P

]W

(c

r \

V

IMO

]CO

I

AG

A

ISI

M-5

0

U.8

2

0.2

4

0.2

6

0.0

03

(V

IM-V

AN

(VA

R)

A J

Va

sco

0

.12

0

.88

0

.29

0

.00

8

0.0

12

1

.32

4

.95

0

.42

1

.34

0

.02

X

-2

AK

V

asc

o

1 S

am

e a

s T

est

Se

rie

s A

J

? Fe) -

Re

ma

rks

I

51 0'C

(950.F) tamper

P

AL

V

a sc

o

0.1

4

0.9

4

0.2

40

0.0

11

0

.01

1

1.40

4.7

6

0.4

5

1.4

0

0.0

3

0.1

0

--

0.06 316'C(6CO'F\templsr

X-2

/VA

R)

AM

/ ~

as

co

1

Sa

me

as

Tes

t S

er

ies

A1

Va

sco

- M

ax 3

50

TA

BL

E 2

7 (C

onti

nu

ed)

Pa

ge

2.

CH

EM

ICA

L COMPOSITION OF T

ES

T MATERIALS TOR P

HA

SE

III

Matrix

11 (

VA

R)

AP

A

ISIM

-50

0

.80

0

.22

0

.24

0

.00

5

0.0

06

0

.04

3

.98

0

.98

4

.18

0

.05

0

.07

--

0

.06

(V

AR

)

AD

A

ISI9

31

0

0.1

0

0.2

8

0.5

4

0.0

01

0

.00

6

--

1.1

8

--

0.1

1

--

3.1

5

--

0.0

6

(VA

R)

AR

A

ISI

93

10

0

.11

0.

32

0.5

4

0.0

04

0

.00

5

--

1.2

6

--

0.1

2

--

3.1

6

-- 0

.06

(V

IM-V

AR

)

AS

E

X0

00

14

0

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0

.99

0

.36

0

.00

4

0.0

08

- -

0

.99

0

.11

0

.75

--

2

.96

--

2

.04

--. .

(VA

R)

AT

E

X0

00

53

0

.10

0

.98

0

.37

0

.00

6

0.0

09

--

1

.05

0

.12

3

.30

--

2

.13

--

2-0

7

(VA

R

AIS

I M

- 50

S

am

e a

s T

est Series A

G

Gol

d Plated

(VIM -V

AN

AS

1 M

- 50

S

am

e a

s T

est

Se

rie

s A

G

Chrome P

late

d

(VIM - V

A RJ

APPENDIX B

TABLE 28

PHYSICAL PROPERTIES OF LUBRICANT, STAUFFER JET I

(MIL -L -7808G)

linematic Viscosity, c e

-20" F 100 210 400

F ire Point, O F

Flash Point, " F

Specific Gravity, bO160° F

l'zpor Pressure , mm HF

Specific Heat, BTU/lb-OF

- 5 ca. 10 0 .88 1 .45

( 1 ) - Batch 3979

(2 ) - Vendor Data, Extrapolated or Interpolated

(3 ) - Vendor Brochure

(4) - A F Data

APPENDIX C - TABLE 29

ROLLING CONTACT FATIGUE TESTS - VIM-VAR AISI M-50

(Test Series AC)

Test Condition6

'max = 4, 826 MPa (700 kai) Speed = 6.23 m/ aec (245 in/sec)

(25,000 cyclesf min. ) Lubricant: MIL-L-7808 Temperature: Room-ambient

Test Number I - - - -- - -

Stres s Cycles to Failure

8 ,160 ,000 2,100, coo 4 ,110 ,000 8, 550,000 3,165,000 4,695,000

13,455,000 9 ,900 ,000 6,825,000 3,615,000

14,100,000 5,625,000

12 ,285 ,000 7 ,725 ,000

Weibull Analysis 6 B-10 Liie: 3.34 x 10 cycles

B-50 Life: 7 .77 x l o6 cyc les Slope: 2.23

TABLE 30 - ROLLING CONTACT FATIGUE TESTS - AM CBS600

(Test Series AH)

Te st Conditions

S = 4,826 MPa (700 kai) &%?I - 6.23 m/ aer (245 in/ sac)

(25,000 cycles/min. ) Lubricant: MIL-L -7808 Temperature: Room-ambient

Te st Number

1

2

3

Stress Cycles to Failure 7

27,420,000

3,000,000

4,545,000

4,695,000

2,190,000

4,890,000

7,890,000

11,505,000

13,830,000

5,985,000

Weibull Anslysis 6 B-10 Life: 1.91 x 10 cycles 6 B-50 Life: 7.31 x 10 c y c l e s

Slope: 1.40

TABLE 31

ROLLiNG CONTACT FATIGUE TESTS - VAR CBSl OOOM

(Ter t Seriee AI)

Teat Condition8 S = 4,826 MPa (700 kei)

max Speed = 6.23 m / eec (245 in l rec )

(25,000 cycler /mine ) Lubricant: MIL- L -7808 Temperature: Room-ambient

Test Number Stress Cycles to Failure

Weibull Analysis 6

B-10 Life: 2.08 x 10 cycles 6 B- SO Life: 4.36 x 10 cycles Slope: 2. 55

TABLE 32

ROLLING CQiJTACT FATIGUE TESTS - VAR VASCO X - 2 (316°C TEMPER)

(Test Series AJ)

Teet Conditions S max = 4,826 MPa (700 kei)

Speed = 6.23 m/ sec (245 in/sec) (25,000 cy:les/min. )

Lubricant: MIL-L-7808 Temperature: Room-ambient

Test Number I Stress Cycles to Failure

Weibull Analysis 6

B-10 Life: 2.88 x 10 cycles 6

B-50 Life: 8 . 5 5 x 10 cycles Slope: 1 . 7 3

TABLE 33

ROLLING CONTACT FATIGUE TESTS - VAR VASCO X-2 (510.C TEMPER)

(Test Series AK)

Teat Condition8 s max = 4,826 MPa (700 kri) Speed = 6.23 m/ sec (245 in/ sec)

(25,000 cycles/min, ) Lubricant: MIL-L -7808 Temperature: Room-ambient

Test Number - 1 Stress Cycles to Failure

Weibull Analysis 6

B-10 Life: 1.56 x 1% cycles 8-50 Life: 3 . 9 3 x 10 cycles Slope: 2.03

TABLE 34 -- ROLLING CONTACT FATIGUE TESTS - VAR VASCO X - L (31 6'C T E M P E X .. ,

(Test Ser ies AL)

Teat. Ccnditions S max = 4,826 MPa (700 k r i ) Speed = 6.23 m/ 8ec (245 in/ s e c )

(25,000 cyc les lmin. ) Lubricant: MIL-L- 7808 Temperature: Room-ambient

I Stress Cycles to Failure I

Weibull Analysis - 6 B-10 Life: 3 . 6 3 x 10 6cycles

B-50 Life: 12.24 x 10 cycles Slope* '. 5 5

TABLE 35

ROLLING CONTACT FATIGUE TESTS - VAR VASCO X-2 (316.C TEMPEIi + SHOT PEENED)

(Tert Series AM)

Tert Conditionr S m u = 4,826 MPa (700 ksi) Speed 1 6.23 m/re (245 in/ rec)

(25,000 cycle,/min. ) Lubricant: MIL-L- 7808 Temperature: Room-ambient

- --

Te rt Number ~ --

Stress Cycles to Failure

Weibull .Ana!y~is -- 6

B-10 Lifc: 2.3Q x 183 cycles 6 B-50 Life: 4.42 x 1b cycler Slope: 2.89

TABLE 36

ROLLING CONTACT FATIGUE TESTS - VAR VASCOMAX 350

(Teat Ssriea AN)

Teat Conditions S max = 4,826 MPa (700 ksi) Speed -- 6.23 rn! ..=. (245 in/ssc)

(25,OOO c ,slee/min. ) Lutwicitnt: MIL-1-7808 Temp; raturer Room-ambient

Teat Number Stress Cycles to Failure

Weibull Analysk W-10 Life: 0.14 x 10, cycles B- 50 Life: 0.77 x I 0" cycles Slope: 1.09

TABLE 37 - ROLLING CONTACT FATIGUE TESTS - VAR VASCO MATRIX I1

(Test Series AO)

Teat Conditions s

max = 4,826 MPa (700 ksi) Speed = 6.23 m/ sec (245 in/ sec)

(2 5,000 cycles /min. ) Lubricant: MIL-L-7808 Temperature: Room-ambient

Test Number

1

2

3

4

5

6

7

8

9

10

Stress Cycles to Failure

Wcibull Analysis 6

R-10 Life: 3. 31 x 10 ,cycles I3-50 Liie: 13.89 x 10" cycles Slope: 1.31

TABLE 38

ROLLING CONTACT FATIGUE TESTS - VAR AISI M- 50

(Tes t Ser ies A P \

Test Conditions S max = 4,826 MPa (700 ksi) Speed = 6.2 3 m/ sec (245 in/ sec l

(25,000 cycles/rnin. ) Lubricant : MIL -L-7808 Temperature: Room -ambient

Test Number Stress Cycles to Failure

Weibull Analvs i s

3 ,180,000

5,160,000

2 ,850 ,000

4 ,635 ,000

4 ,410 ,000

3,000,000

6,600, OOC

2 ,205 ,000

2,715,000

3,060,000

B-10 l i f e : L.4b x 1f cyc l e s B-50 Life: 4.01 x 10 cyc les Slope: 3 . 8 5

TABLE 39

ROLLING CONTACT FATIGUE TESTS - VAR AISI 9310

(Test Series AQ)

S max = 4,826 MPa (700 ksi)

Speed = 6 .23 m/ sec (245 in/ sec) (25,000 cycles/min. )

Lubricant: MIL-L- 7808 Temperature: Room-ambient

Test Numbe r Stress Cycles to Failure

36,225,000 suspend

Weibull Analysis 6

8 - 1 0 Life: 2 .25 x 10 bcycles 8 - 5 0 Life: 10.63 x 10 cyc l e s Slope: 1.21

TABLE 40

ROLLING CONTACT FATIGUE CESTS - VIM-VAR AISI 9310

(Test Seriee AR)

Test Conditions S max = 4,826 MPa (700 ksi) Speed = 6.53 mfsec (245 in /sec)

(25,000 cycles/min. ) Lubricant: MIL-L-7808 Temperature: Room-ambient

Test Numkr Stress C y c l c s to Failure -

21,150,000

14,850,000

2 1,450,000

2 1 , 600, 000

9 ,900 ,000

2 1 , 150,1100

14, 100,000

6 ,300 ,000

7, 800, OOO

2 1,900,000

Weibull Analysis -- 6

B-10 Life: 6 .84 x 10 .cycles b

R-SO Lifc: 15.74 x 10 cycles Slope: 2 . 2 6

TABLE 41

ROLLING CONTACT FATIGUE TESTS - VAR EX00814

(Tort Serial AS)

Test Conditions s max = 4,826 MPa (700 kai) Spaed = 6.23 m/ see (245 in/ sec?

(25,000 cycles jmin. ) Lubricantt MIL-I*-7808 Temperature: Room -ambient

I Stress Cycles to Failure I

Weibull Analysis B-10 Life: 3 . 2 7 s 10 i , c y c l ~ s

Slapc: 1. 31

TABLE 42

ROLLING CONTACT FATIGUE TESTS - VAR EX00053

(Teat Series AT)

Te st Conditions S max = 4,826 NPa (700 ksi) Speed = 6 . 2 3 m/ sec (245 in/sec)

(25,000 cycles/min. ) Lubricant: MIL-L-7808 Temperature: Room-ambient

Test Number Stress Cycles to Failure

Weibull Analysis 6 D-10 Life: 1 . 9 5 x 10 6cycles B-50 Life: 11.58 x 10 cycles Slope: 1.05

TABLE 43

ROLLING CONTACT FATIGUE TESTS - VIM-VAR AISI M-50 (Gold Platad)

(Test Series AU)

Test Conditions

S max = 4,826 MPa (700 kai) Speed = 6.23 misec (245 inisec)

(25,000 cycles/min. ) Lubricant: M'L-L-7808 Temperature: Room-ambient

- Te st Num be r Stress Cycles to Failure

Weibull Anal) s is 6

B-10 Life: 4.21 x lo6 cycles B-50 Life: 8.88 x 10 cycles Slope: 2 . 5 3

TABLE 44

ROLLJNG CONTACT FATIGUE TESTS - VIh4-VAR AISI M-50 (Ghronas Plated1

(Teat Serier AV)

Test Conditiona

S max = 4,826 MPa (700 k a i ) Speed = 4 .23 m/ sac (245 in/ aec)

(25,000 cyclea/rnin. ) Lubricant: MIL-L- 7808 Temperature: Room-ambient

Teat Number

1

2

3

1

t*

1

H

Q

I Q

Weil~irll A n a l y s i s b

U - 1 0 1,ife: 2 . 2 8 s 10 r.yclcjr b B - 5 0 Life: 1l l . t lb x 10 cyc les

Slope: I . 22

Test

Co

nd

itio

ns

Smax

=

4,8

26

MP

a(7

00

kei

) S

pee

d =

6.2

3 d

se

c(2

45

id

se

c)

Lu

bri

can

t - M

IL-L

-780

8 T

emp

era

ture

- R

oom

-am

bie

nt

Fa

ilu

rs

In

dex

- 2

7/2

7

FATIGUE LIFE,

STR

ESS

C

YC

LE

S

Fig

ure

3

3,

RCF

Te

st Results o

f VIM-VAR AISI M-50

(Te

st

Se

rie

s A

G)

I Test Conditions

Sm

ax r 4.826 YPa(7M)ksi)

Speed =

6.23

ds

ec

(24

5 i

ds=)

Lubricant - M

IL-L

-780

8 Temperature -

Room-nmbient

Failure Index -

10/10

lo7

lo8

FA

TIG

UE

LIF

E,

STR

ESS

CY

CL

ES

Figure

34

. R

C6 Test

Res

ult

s of

AM CBS 600 (Test Series A

H)

Fig

ur

e 15.

Te

st Conditions

Smax

= 4.826

MP

a(7

00

Lsi

) S

pee

d =

6.2

3 d

se

c(2

45

ids-)

Lubricant - M

XL

-L-7

808

Tem

per

atu

re - R

oom-ambient

Fa

ilu

re Index - 1

0/10

lo7

lo8

FAT

IGU

E LIFE,

STR

ESS

C

YC

LE

S

RC

F Test

Re

sult

s o

f VAR C

BS-

10W

M

(~

es

t

Se

rie

s A

I)

Te

st Conditions

Smax =

4,826 MPa(700ksi)

Speed

= 6.23

ds

ec

Lubricant - M

IL-L -7808

Temperature -

Room-ambf ent

Failure

Ind

ex

- 10/10

I ocj

i o7

FA

T1C

I.X

LIFE, STRESS CYCLES

Fig

ur

e

39

. fC

CF

Te

st

Rc

s:ll

ts of

I'AR

V

AS

CO

X-2,

(Te

st Series A

J)

Test Conditions

Smax =

4,826 MPa(700lmi)

Speed = 6.23

de

ec

Lubricant - M

I L-L-7808

Temperature -

Room-ambient

Failure Index

- 10/10

FATIGUE L

IE'E

, STRESS CYCLES

Fig

ure

37.

RCF Test Results of VAR VASCO X-2,

Tempered at 510~~

(Test Series A

K)

Fig

ur

e 38.

Test Conditions

Sm

x r

4,8

26

MP

a(7

00

ksi

) Speed =

6.2

3 d

se

c

Lubricant - M

IL-L

-780

8 T

emp

era

ture

- Room-ambient

Failure Index -

10/10

FATIGUE L

IFE

, ST

RE

SS CYCLES

RC

F T

est

Re

sult

s of

VA

R

VA

SC

O

X-2

, T

emp

ered

a

t 3

l6

*~

, (T

est Series A

L)

Fig

ure

39

.

Te

st C

on

dit

ion

s sm

ax t

4.8

26

MP

a(7

00

ksi

) S

pee

d =

6.2

3 d

se

c(2

45

in/.-)

Lu

bri

can

t - M

IL-L

-780

8 T

emp

erat

ure

- R

oom

-am

bie

nt

Fa

ilu

re

In

dex

- 1

31

13

FA

TIW

E L

IFE

, ST

RE

SS CYCLES

RCF

Tes

t R

esu

lts

of

VA

R V

ASC

O X-2,

Tem

per

ed

at 316'~

(sh

ot-

pee

ned

, T

est

S

er

ies

AM

)

Test Conditions

Smax

n

4.826 MPa(700ksl)

Speed = 6.23 dsec(245 idsec)

Lu

brf

cant - M

IL-L-7808

Temperature -

Room-ambient

Failure Index - 1

0/10

FATIGUE LIFE,

ST

RE

SS

CYCLES

Figure 40, RCF Test Results of VAR VascoMax 350 (Test Series AN)

Test Conditions

Smnx n

4,826 MPa(700kei)

Speed =

6.23 dsec(245 In/@ec)

Lubricant - M

IL-L-7808

Temperature -

Room-ambient

Failure Index - 1

0/10

FATIGUE LIFE, STRESS C

YC

LE

S

Figure 41.

RCF Test Results of VAR Vasco Matrix I1 (Test Series A

O)

Test Conditions

Smax =

4,826 MPa(700ksi)

Speed

= 6.23 dsec(245 in/sec)

Lubricant - M

IL-L-7808

Temperature - R

oam-ambient

Failure Index - 9

/10

FATIGUE LIFE, STRESS CYCLES

Figure 43.

RCF Test Results of VAR AISI 9310 (Test Series AQ)

Test Conditions

Sm

ax

= 4,826 MPa (7OOksI)

Speed

= 6.23 d

se

c (2

45

in

/se

c)

Lubricant - M

IL-L-7808

Temperature - R

oom-ambient

Failure Index - 10/lO

FATIGUE LIFT,

STR

ESS

CYCLES

Fig

ilre 44.

'LC

F Test Results of

VI!

d-V

AR

9310 (Test Series A

R)

Ir it-

1 Test Conditions

:

"x

=

4,8

26

MPa(700ksi)

Speed = 6.23 deec(245 in/sec)

Lubricant - M

IL-L

-780

8 Temperature - Room-ambient

Failure Index - 1

0/10

FATIGUE

LIF

E,

.ST

RE

SS

CY

CL

ES

Figtire 45.

WF

Test Results of VAR EX00014 (Test Series AS)

Test Conditions

Sm

ax

= 4,826 MPa(700ksi)

Speed

= 6.23 dsec(245

i n

/sec

) Lubricant - M

IL-L

-780

8 Temperature - R

oom-ambient

Fa

fLu

re Index - 1

0/10

lo7

i0 8

FATIGUE L

IFE

, ST

RE

SS

CY

CL

ES

fig

ur

e

46

. R

CF Test

Ke

sult

s of VAR MOO053 (Test

Serie

s AT)

Test Conditions

Sm

ax

= 4,826 M

Pa (

70

0b

i)

Speed

= 6.23

ds

ec

(24

5

in/~

€?

c)

Lubricant - M

IL-L-7808

Temperature - R

oom-ambient

Failure I

ndex - 1

0/10

FATIGUE LIFE,

STR

ESS

C

YC

LE

S

Figure 47.

RC

F Test Results of VZX-VAR

AS

S1

H-50 (gold plated, Test

Se

rie

s AU)

AP

PE

ND

IX E

TA

BL

E 4

5

SU

MM

AR

Y O

F R

CF

TE

ST

RE

SU

LT

S A

ND

ME

TA

LL

UR

GIC

AL

CH

AR

AC

TE

RIS

TIC

S

OF

TE

ST

MA T

ER

IAL

S F

OR

PH

AS

E 1

11

Lif

e

. x lo

6

Wei

bu

'

B-5

0

r

B-I

0

Lif

e

, 1

0'

Cy

cle

s -

-

3.3

4

Ca

se

R

eta

ine

d

Au

ste

nit

e

Re

ma

rks

V

ol.

%

N.

D.

Rep

!ace

s N

itra

llo

y N

22

.8

Eff

ec

tiv

e

Ind

ex

mm

(in

. ]

27

/27

Su

rfa

ce

H

ard

ne

ss

H

RC

63

.0

Seri

es

T

AG

Te

st

Ma

teri

als

(M

elt

ing

Pr

oc

es

~

AIS

I M

-50

(V

IM-V

AR

)

C B

S6

00

(A

M)

C B

S1

00

0M

(V

AR

)

Va

sco

X-2

(V

AR

)

Co

re

Ha

rdn

es

HR

C

Cy

cle

s /

Slo

pe

7

5.0

3

16

-C

(60

0. F)

tem

per

N.

D.

51 0

-C

(95

0-F

) te

mp

r

11

.0

31

6-C

(6

00

-F)

tem

pe

r

11

.0

316.

C

(60

0.F

; t

em

p r .

sho

t p

ee

ne

d

N. D

. A

ge

h

ard

en

ed

Va

sco

X-2

(V

AR

)

Va

sco

X-2

(V

AR

)

-

Ah

i

Va

sco

Ma

x

350

(VA

R)

TA

BL

L

45

P

ag

e 2

.

SU

MM

AR

Y 0''

RC

F T

ES

T R

ES

UL

TS

AN

!)

ME

TA

LL

UR

GIC

AL

C:H

AR

AC

TE

RIS

TIC

S

-

-

Te

st

Te

st

Ma

teri

als

S

eri

es

(Me

ltin

g P

roc

es

s

A0

V

asc

o M

atr

ix I

1

(VA

R)

AP

A

ISI

M-'

JIJ

(VA

RI

- A

Q

AIS

I 9

31

0 i

VA

R)

AIS

I 9

31

0 (

VIM

- V

AR

I

EX

00

01

4 (

VA

R)

AIS

I M

- 5

0

(VIM

-VA

R)

AIS

I M

-50

(V

IM-V

AR

,

OF

TEST ,

MA

rE

K1

AL

.S F

OR

PH

AS

E I

11

(Co

nti

nu

ed

)

- B

-10

B

-50

L

ife

L

ife

E

ffe

cti

ve

S

urf

ac

e

Co

re

, x

lo6

,

x

lo6

W

'eih

ull

Fa

ilu

re

Ca

se

Q

pth

H

ard

ne

ss

H

ard

ne

ss

C

yc

les

C

yc

les

S

lop

e

!ndex

rnrn

(in

.)

HRC

HRC -

I

3. 3

1

10

11

0

- -

61

.8

- -

I

Ca

se

R

eta

ine

d

Au

ste

nit

e

Vo

l. '70

N. D.

Re

ma

rks

Re

pla

ce

s

RE

X 7

29

Go

ld

Pla

ted

Ch

rcm

e

Pla

ted