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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
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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
.11
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
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