torque tension loss
TRANSCRIPT
(LR-25049) TORQUE-TEISION RELATIONSHIPS AND-2, : STATIC PRELOAD LOSS OF HIGH STRENGTH, t l i i A i ! :.
RESISTANT , AND CORROSION RESISTANT AIHCP AET !' ''
ALLOY FASTENERS (Lockheed-California Co.) .,
TITLE
REPORT NO. Lfi L3ur7
DATE 12-23-71
MODEL
COPY NO. .i, TORQUE -TENSION RELATIONSHIPS STATIC PRELOAD LOSS OF HIGH ST HEAT RESISTANT, AND CORROSION RESISTANT AIRCRAFT ALLOY FAST
L O C K H E E D * C A L P F O I W N I A C O M P A N Y A D I V I S I O N O F L O C K H E E D A I R C R A F T C O R P O R A T I O N
IIEVISIOI\IS
I. ABSTRACT
This r epor t was prepared by the P a r t s and Equipment Department under
an Independent Development P r o g r a m . It descr ibes torque-tension and static
preload. l o s s tes t s conducted on high strength, heat res i s tan t , and cor ros ion
res i s tan t fas teners that a r e cur rent ly used o r intended for future use in
Lockheed-California Company a i rc raf t . All testing was conducted by Almay
Resea rch and Testing Corporation. All fas tener hardware was supplied by
Lockheed. The r e su l t s of this repor t m a y be used to determine the installation
torque requi rements for optimum joint preload.
The tes t data resulting f r o m this p rogram was generated by wrenching
the nut and was l imited to two installation cycles . The effect of two different
added lubricants was determined. These lubricants were MIL-T-5544, a
graphite base lubricant, and MIL-L-23398 (LAC -C34-1209A), a d r y f i lm
The conclusions of this r epor t a r e that the installation torque requi rements
of f a s t ene r s vary due to fastener ma te r i a l s , lubricants used, ra ted s t rength
of the f a s t e ~ e r , f inishes, and installation cycle number. In addition, each
installed fastener i s subject to a l o s s of preload during the f i r s t 7 2 hours af ter
installation; this l o s s m a y be a s much a s 11 percent of the init ial preload.
FORM 4020
L O C K H E E D * C A L I F O W M I A C O M P A N Y A D I V I S I O N O F L O C K H E E D A I R C R A F T C O R P O R A T I O N
REVISIONS REPORT NO.
PAGE NO.
11. ACKNOWLEDGEMENTS
The au thors w i sh to acknowledge the valuable a s s i s t a n c e prov ided dur ing
the c o u r s e of th i s p r o g r a m by the following f a s t ene r companies : E l a s t i c Stopnut
Division of A m e r a c e E s n a Corporat ion, Kaynar Manufacturing Co . , I n c . ,
O m a r k Indus t r i es P r e c i s i o n Fas ten ing Subsidiary , P. B. F a s t e n e r s Division of
P a u l R . B r i l e s , Inc. , Standard P r e s s e d Steel Co. , Valley Todeco, Inc. , Sub-
s i d i a ry of The Larnson Sess ions Co. and Voi-Shan, a division of VSI Corporat ion
T h e au thors fu ther acknowledge the contribution of Almay R e s e a r c h and
Tes t ing Corpora t ion i n pe r fo rmance of the tes t ing, which w a s accompl i shed
SECTION PAGE
ABSTRACT
ACKNOWLEDGEMENTS
TABLE O F CONTENTS
LIST O F TABLES
INTRODUCTION
OBJECTIVE
CONC LUSIONS/RECOMMENDATIONS
ii
iii
PARTS TESTED
TEST SPECIMENS
TEST PROCEDURE
DISCUSSION O F TEST RESULTS
APPENDIX
LIST O F REFERENCES
BIBLIOGRAPHY
IDC, , PE70/522 , J. B. Bie rbower to G,. V?. Davis , Dated 7-28-70, Subject: Torque-Tens ion Relationship - Engine To Py lon Attach Bol t s
DISTRIBUTIGN LIST
FORM 4020
L O G R H E E D C d L I F O I W M I I A C O M P A E Q Y A D I V I S I O N O F L O C K H E E D A I R C R A F T C O R P O R A T I O N
REVlSlONS
TABLE
IV. L I S T O F T A B U S
TITLE
TORQUE-TENSION TEST SPECIMEN COMBINATIONS
PAGE
I1 PRELOAD- LOSS TEST SPECIMEN COMBINATIONS I
L O C K H E E D * CALlIleORlPaBlIA C O M P A N Y A D I V I S I O N O F L O C K H E E D A I R C R A F T C O R P O R A T I O N
REPORT NO. LR 49
I Shear, tension, and fatigue cri t ical bolts and nuts require different
1 installation torque l imits in order Lo achieve optimum joint preload. Fatigue-
sensitive, highly loaded joints a r e subject to premature failure of the s tructure
or fastener i f the fastener installation torque i s below optimum. An installation
torque greater than optimum can cause premature fastener failure by inducing
preloads greater than the fastener yield strength. Torque -tension relationships
for alloy steel , cadmium plated bolts and steel, cadmium plated, dry film -1. ' P
lubricated nuts a r e well documented (1). These established relationships a r e
available to designers via various reference manuals. The f i rs t objective of
this test program was to establish torque-tension relationships for fasteners
of mater ia ls other than those already documented. It had been suggested that
fastener preload attained from torque is subject to a loss with time. This loss
may be a result of relaxation in the joint or room temperature creep in the
fastener . This phenomena has not been investigated to any great degree by
pr ior investigators. The second objective of this program was to determine
the magnitude of preload loss a s a function of t ime for fasteners that a r e
currently in use.
After this test program was initially defined a recent torque-tension test
report ( 2 ) prepared by Almay Research and Testing Corporation under a NASA
contract was made available to us. After review of this test report our proposed
program was revised to eliminate duplication. The two programs now comple-
ment each other.
'::Numbers in parenthesis r e f e r to references listed in the Appendix,
FORM 4OZD
B O C K H E E D ~ A L I F O R M I A C O M P A N Y A D I V I S I O N O F L O C K H E E D A I R C R A F T C O R P O R A T I O N
REVISIONS REPORT NO.
PAGE NO.
V. INTRODUCTION (C ontinued)
Almay Research and Testing Corporat ion was selected to conduct
the testing f o r this program. Almay was chosen because: 1, they had just
completed the torque -tension study for NASA (which resul ted in a r epor t
of over 700 pages, see Ref 2), 2. they were located in the Los Angeles
a r e a s o testing could be monitored and coordination could be conducted
easi ly , and 3. their es t imate of cost was in line with budget predictions.
Testing was conducted under the supervision of Mr. H a r r y S. Brenner ,
Director of Research. Mr. Brenner offered to provide a wri t ten r epor t ,
besides the tes t data requi red by contract a t no additional charge. It was
fe l t that this repor t , which includes observations, photos, description
of t e s t equipment, and comments , would add greatly to the value of this
program. F o r this reason Mr. B r e n n e r l s offer was accepted. His
r epor t ( 3 ) h a s been submitted to the Lockheed-C alifornia C ompany l ib ra ry
OBJECTIVE
The f i r s t objective of this program was to provide torque-tension data
for bolts and nuts f rom which installation torque requirements could be
determined.
The second objective of this program was to determine the magnitude
of any static preload loss , a s a function of t ime, so that i t s significance could
be established.
FORM 4320
L O C K H E E D * C A L l F O R N l A C O M P A N Y 14 D I V I S I O N O F L O C K H E E D A I R C R A F T C O R P O R A T I O N
REVISIONS
VII. CONCLUSIONS/RECOMMENDATIONS
The t es t r e su l t s will provide a i r c ra f t design engineers with accura te
torque--tension relationships f r o m which fas tener optimum installation torque
l imi ts (can be determined.
The data generated by this t e s t p rogram m a y resu l t in: (1) longer
lived, m o r e reliable a i rc raf t , ( 2 ) industry standardization of installation
torque l imits and methods, and ( 3 ) extending the life of the fas tener wrenching
sur faces .
It i s recommended that fur ther torque-tension t e s t s be conducted on
high strength, heat res i s tan t , cor ros ion res i s tan t f a s t ene r s . The object of
these t e s t s would be to determine the influence on joint preload due to:
( 1 ) Fas tener yield to ultimate rat io caused by flush, hex, and
12-point bolt head configurations,
(2 ) Wrenching the bolt versus wrenching the nut,
(3 ) Nut configuration (thin wall, thick wall, and plate nut types),
(4) Nonlocking ve r sus self-locking nuts,
( 5 ) Varying the thread pitch f rom fine to c o a r s e (in preparat ion for
"intermediate" pitch of future me t r i c s tandards) ,
(6) Varying washer ma te r i a l s , heat t r e a t levels, f inishes, and
dimensions,
FORM 4023
L O C K H E E D C A L I F O R N I A C O M P A N Y A D I V I S I O N O F L O C K H E E D A I R C R A F T C O R P O R A T I O N
REVISIONS REPORT NO.
C ONC LUSIONSfREC OMMENDATIONS (Continued)
( 7 ) 15 installation-removal cycles with and without added lubricants
and methods of achieving minimum variation between cycles ,
(8) Sealants f o r e i ther environmental o r d iss imi lar m e t a l protection,
( 9 ) Other fas tener mater ia l s . An example i s Multiphase (MP-35N),
a propr ie ta ry mater ia l of the Standard P r e s s e d Steel Co. Multi-
phase h a s seve ra l proper t ies that an excellent fastener alloy
should have. I t i s elevated tempera ture res i s tan t , h a s a very
low magnetic permeabili ty, i s very cor ros ion res i s tan t , hea t
t reatable to 260 KSI minimum ultimate tensile strength, and
dynamically i t i s a t l eas t equal to the bes t of the available
noncorrosion res i s tan t mater ia l s . It i s hoped that any f u t ~ r e
torque -tension t e s t program would include sufficient quantities
of MP-35N bolts s o that torque-tension relationship data for
this m a t e r i a l could be established,
Future preload los s studies a r e a l so recommended, The effect of
vibration on preloz~d los s in the joint needs to be determined.
FORM 4020
CONC LUSIONS /RECOMMENDATIONS (Continued)
Finally i t i s recommended that the data generated by this program be
reduced into a form m o r e readi ly useable, by design engineers , in specifying
installation torque l imits for optimum joint preload. Th i s information
shoi~ld be published in the S t r e s s Memo Manual.
L O C K H E E D ~ A L I F O R N I A G ~ M P A N V A D I V I S I O N O F L O C K H E E D A I R C R A F T C O R P O R A T I O N
iFiEv!S!oNS REPORT NO. LR 25049 PAGE NO. -i
VIII . PARTS TESTED
The p a r t s tes ted a r e shown in Tables I and 11. These p a r t s were
paired a s shown in the tables. The tables also show that the p a r t s were
t reated ei ther a s a tension combination o r shear combination, and the added
lubricant used, if any.
In some c a s e s the a s received p a r t s were only tested with added
lubricants. It was felt that these p a r t s should always be installed with added
lubricants in o rde r to minimize the installation torque requirements , and that
the adding of a lubricant would provide the m o s t consistent torque-tension
r,elationships between specimens and be tween installation cycles .
FORM 402D
TABLE I - Torque-Tension Tes t Specimen C ornbinations
::: Sources of manufac turer ' s p a r t numbers a r e shown below Table 11.
NAS6404U15 NAS129lC4M NAS6405U31 NAS1291C5M As Received NAS6406U 34 NAS1291C6M
09LH9074-8
NAS6404U15 LH7875-4 NAS6405U3 1 A s Received
As Received
MIL-T -5544 NAS6406U34 NAS1291C6M
MIL-T -5544
NAS6304U16 NAS6405U31 MIL-T -5544 NAS6406U34
MIL-T -5544
1 L O C K W E E D C A L i F O R N I A C O M P A N Y A D I V I S I O N O F L O C K H E E D A I R C R A F T C O R P O R A T I O N 1 RLVISIoNS REPORT NO.
PAGE NO. 9
TABLE I (Continued)
Bolt Nut :g
P a r t No. I P a r t NO. Combination
Rating
Tension
Shear
Tension
Tension
Tension
Tension
Tension
Tension
Lubrication Condition
MIL-T -5544
MIL-T -5544
As Received
n/IIL-T -5544
:+ Sources of manufac turer ' s pa r t numbers a r e shown below Table 11.
I
1 FORM 4020
TABLE I1 - P r e l o a d L o s s T e s t Spec imen Combinations
s : ~ Sources of m a n u f a c t u r e r ' s p a r t n u m b e r s a r e shown below.
NAS1103-12 MS2 1042L3 NAS1104-17D MS2 1042L4 NAS1105-22D MS2 1042L5 A s Received
MS21250-05022 MS21250-06024
MIL-T-5544
l~lS21250-05022 MIL-L-23398
NAS6404U15 A s Rece ived
NAS6403U12 LH7875-3 NAS6404U15 LH7875-4 NAS6405U31
A s Received LH7875-5
NAS6406U34
NAS6405U31 NrlS1291C5M A s Rece ived
NAS1291C5M A s Rece ived
NAS6303U28D NAS1291C6M
FORM 4020
A D I V I S I O N O F L O C K H E E D A I R C R A F T C O R P O R A T I O N
REPORT NO.
T A B L E I1 - (Continued)
NOTE: Al l f a s t e n e r combinat ions t e s t ed w e r e cons ide r ed to be tens ion ra ted. T h e r e w e r e no s h e a r r a t e d f a s t e n e r combinat ions tested.
::: P a r t Number S e r i e s Manufac tu re r
BMN4122 O m a r k
L,H10205, LH7559, LH7875, 109LH9074 ESNA VEP220555 Val ley Todeco 48FT , 69678, 696.80, 70718, 72914, 73178 S tandard P r e s s e d S t e e l
NAS6303U13D MS2 1043 -3 NAS6304U17D MS2 1043 -4 NAS6305U34D MS2 1043 -5
A s Rece ived
VEP220555-4-16 LH10205-4 VEP220555-5-22 LH10205-5 MIL-T -5544 VEP220555-6-22 LH10205-6
MIL-T-5544 7071SV6-23
MIL-T-5544
MIL-T-5544
L O C K H E E D e A L l F o o w i r i a e M p A w y 14 D I V l S l O N O F L O C K H E E D A I R C R A F T C O R P O R A T i O N
~ ~ E V ~ S ~ O I N S REPORT NO.
PAGE NO.
IX, TEST SPECIMENS
The t e s t specimens consisted of a bolt, a nut, 2 washers , and a
load ce l l assembled in a fixture. The load ce l l s utilized s t ra in gages so
that loads could be determined. These load ce l l s were designed to com-
pensate for bending and &erefore bending in the t e s t specimen did not
effect the load readings. The ar rangement of the t e s t s e t up i s represented
FORM 4020
F I G U R E I - T E S T SET U P
L O C K H E E D * C A L 1 1 F O R N r A C O M P A H Y A D I V I S I O N O F L O C K H E E D A I R C R A F T C O R P O R A T l O N
REViSIONS REPORT NO.
PAGE NO.
X . TEST PROCEDURE
All t e s t s were per formed during the period between September 1, 1971
and December 23, 1971.
111 o r d e r to preload the bolts to loads between 8 0 and 9 0 percent of
yield strength i t was necessa ry to determine bolt-nut combination yield
s t rengths. Two methods were permit ted. The f i r s t method was in accordance
with Tes t 8 of MIL-STD-1312. This involves loading the nut and bolt axially
in a tensile machine and obtaining a load-deflection curve. Bolt yield s t rength
was then determined using Johnson's 2 /3 approximate method. The second
method utilized the torque-tension test f ixture. Using a torque wrench, the
nut was turned on to the bolt in increments of torque. Torque and s t ra in
were recorded for each increment . Torque was increased until s t r a in readings
indicated that the bolt-nut combination had been loaded past yield point o r to
fai lure . In subsequent t e s t s the f a s t ene r s ,were loaded proportional to the
yield s t rength a s determined by ei ther of these methods.
Torque- tension t e s t s were conducted in accordance with Tes t 15 of
MIL-STD- 131 2 except for the following. Compression load ce l l s were used
in conjunction with torque wrenches to determine the torque-tension
relationships. The load ce l l s were calibrated and calibration cu rves
were obtained. Torque wrenches were accurate to within i6 percent .
FORM 402D
L O C K H E E D * C A L I F O R N I A C O M P A N Y A D I V I S I O N O F L O C K H E E D A I R C R A F T C O R P O R A T I O N
REVlSlOfqS REWRT NO. LR 25049
PAGE NO. 15
X. TEST PROCEDURE (C ontinued)
Countersunk washers were placed under bolt heads, and plain washers
were placed under the nut. Tes t specimens were assernbled in the tes t
fixture a s represented by Figure I. Torque was applied in increments
until s t rain readings approached values indicating that the desired preload
of 80 to 90 percent of bolt-nut yield strength had been reached, The
fastener was then disassembled and the procedure was repeated to obtain
a second set of datum points. Where lubricants were added, they were
applied to bolt threads and nut-washer interface in a conservative manner.
The bolt head was held stationary and the nut was turned onto the bolt in
al l cases. Three specimens were tested for each test condition.
The preload-loss tests utilized the same test fixtures. The bolt-
nut combination was preloaded to 80 to 90 percent of yield a s indicated by
strain readings. Strain readings were made a t one hour intervals for the
f i r s t eight hours, twice in the next 24 hours, and daily for the next two days.
Total time for each test was not l e s s than 70 hours. Application of torque
was to the nut with the bolt held stationary. Lubricants, where used, were
applied to the bolt threads and nut-washer interface in a conservative manner.
The initial s t rain readings were made while the installation seating torque
was maintained. The second strain reading was made 3 minutes af ter the
110CPdlHEED C A L I F O R N I A C O M P A N Y A D I V I S I O N , O F L O C K H E E D A I R C R A F T C O R P O R A T I O N
REVlSSONS REPoRT NO. LR 25 049
PAGE NO. 16
X. TEST PROCEDURE (Continued)
torque wrench was removed f r o m the fas tener . Three specimens were
tested for each test condition.
A.11 testing was conducted a t room ambient tempera ture and humidity.
FORM 4020
A D I V I S I O N O F L O C K H E E D A I R C R A F T C O R P O R A T I O N
XI. DISCUSSION O F TEST RESULTS
The reduction of the test data was beyond the scope of this p rogram
and therefore no specific recommendations fo r installation torque l imits a r e
made herein.
Generally speaking the torque - tension t e s t s indicated that there was
considerable difference between the 3 individual specimens in a given group
and between the groups of specimens of each thread s ize . F o r example, fo r
a l l groups of . 1900-32 threaded fas teners , installed to 40 inch pounds of
torque, there was a difference of 1, 739 pounds in the induced bolt preload
between the lowest and highest values. F o r 160 KSI tension rated fas teners
this aznounts to 50% of the minimum ultimate tensile strength. This can be
attributed to the differences in ma te r i a l s , f inishes, lubricants, and the
configuration of the p a r t s tested. This amount of variation would indicate that
one set of general torque l imi ts i s not going to utilize each fas tener at i t s
optimum capability.
Pre load loss t e s t s showed s imi lar differences in the fas tener preload
a s a resu l t of the installation torque, however, the object of this portion of the
p rogram was to determine how loss of fas tener preload va r i e s in a static joint
as a function of t ime. It was determined that eve ry specimen lost some of i t s
preloa.d, and the los s varied between 1 and 11 percent . The grea tes t l o s ses
0ccuri:ed in the f i r s t eight hours af ter installation. The preload appeared to
be stabilizing by the end of the 7 2 hour observation period.
L O C K H E E D C A L I F O R N I A e o w ~ n i ~ v A D I V I S I O N O F L O C K H E E D A I R C R A F T C O R P O R A T I O N
REVISIONS REPORT N
PAGE NO.
XI. DISCUSSION OF TEST RESULTS (Continued)
The extensive detailed tes t r e su l t s a r e recorded in Almay Research
and Testing Corporation Report Number A5417, and i s available f rom
Locklieed-California Compzny l ibrary. The accession number i s 72-3296,
F o r thos6 interested in fur ther study of torque-tension relationships
a bibliography of recent publications i s appended to this report .
The appendix a l so includes an IDC which r e p o r t s the r e su l t s of a
torque-tension tes t on the I inch diameter VEP220555 bolts and LH10205 nuts.
This IDC h a s been included because this fas tener i s pa r t of the s e r i e s tested
in this program. Since the information in this IDC supplements the data. in
this repor t , it h a s been included a s pa r t of this report .
FORM 4029
REPORT NO.
APPENDIX
L O C H W E E D a C A L 1 F C ) R M i A C O M P L a a H V A D I V I S I O N O F L O C K H E E D A I R C R A F T C O R P O R A T I O N
iREViS!alNS REPORT NO.
PAGE NO.
L I S T O F R E F E R E N C E S
( 1 ) J. I. P R I C E a n d D. K . TRASK - T h e R e l a t i o n B e t w e e n T o r q u e a n d T e n s i o n f o r High S t r e n g t h F a s t e n e r s . B u r e a u of Nava l Weapons ( B U W E P S ) R e p o r t No. R U E - 343-61-1 . P r e p a r e d by t h e Na t iona l B u r e a u of S t a n d a r d s , A u g u s t 1961. U n c l a s s i f i e d
( 2 ) H. S. B R E N N E R - D e v e l o p m e n t of Techno logy f o r I n s t a l l a t i o n of M e c h a n i c a l F a s t e n e r s . Nat iona l A e r o n a u t i c s a n d S p a c e A d m i n - i s t r a t i o n R e p o r t No. NASA CR -1 031 79 (N7 1-26568) . P r e p a r e d by A l m a y R e s e a r c h a n d T e s t i n g C o r p o r a t i o n . 1971. U n c l a s s i f i e d
(3 ) H. S . BRENNER - R e s u l t s of T o r q u e - T e n s i o n R e l a t i o n s h i p S tudy 1 P r o g r a m of V a r i o u s S t r i l c t u r a l B o l t s a n d Mat ing Nuts S u b m i t t e d by T h e L o c k h e e d - C a l i f o r n i a C o m p a n y , B u r b a n k , C a l i f o r n i a . A l m a y R e s e a r c h a n d T e s t i n g C o r p o r a t i o n R e p o r t No. A5417 , I D e c e m b e r 23, 1971. U n c l a s s i f i e d
BIBLIOGRAPHY
Andrew J. Arnoldi - What ' s a Tight F a s t e n e r ? , Assembly Engineer ing, August, 1971, p g s 24-27
Thomas C . Baumgar tne r and F r a n c i s R . Kul l - Determin ing P r e l o a d in a Bolted Joint.
V
Machine Design, F e b r u a r y 13, 1964, Rep r in t
H a r r y S . B renne r - F a s t e n e r Specifications, Assembly Engineer ing, August 1964, Rep r in t
Robe r t A. Degen - Preva i l ing - Torque Locknuts - What They A r e and Where They Should B e Used,
Assembly Engineer ing, June 197 0, pgs 30-34
Robe r t A. Degen - Preva i l i ng - Torque Locknuts - What They A r e and Where They Should Be Used . . . , P a r t 2
Assembly Engineer ing, July 197 0, pgs . 28-31
Ralph J. E r i s m a n - Torque-Tens ion Relat ionships of Th readed F a s t e n e r s , F a s t e n e r s , Winter 1968/6$,
Volume 23, No. 4, pgs 9-11
Rober t J . F inke l s ton - How Much Shake Can Bolted Jo in t s T a k e ? , Machine Design, October 5, 1972, pgs 122-1 25
J a m e s E . F o i s y - Analysis of Nut and Bolt Torques , P a r t 2 I
Assembly Engineer ing, January , 1968, pgs 20- 22 1
Samue l C . Gambre l l , J r . - Why Bol ts Loosen Machine Design, October 24, 1968, pgs 163-167
F r a n k L. Gi l l - Bas i c F a s t e n e r Funct ions i n Envi ronments 1 of Mechanical S t r e s s , P a p e r p r e sen t ed a t U. C . L. A.
Extension Cour se , Mechanical F a s t e n e r s , F e b r u a r y 8-10, 1972
F r e d G r a v e s - F a s t e n e r P r e l o a d - Why?, Assembly Engineer ing, October 1970, pg 32
F r e d G r a v e s - F a s t e n e r P r e l o a d - How?, Assembly Engineer ing, November 197 0, pg 32
FORM 4020
L O C K H E E D C A L I F O R N I A C O M P A N Y A D I V I S I O N O F L O C K H E E D A I R C R A F T C O R P O R A T I O N
WEvIsIoIqS REPORT NO.
PAGE NO.
BIBLIOGRAPHY (Continued)
T o m Green - Select F a s t e n e r s fo r Fu l l To rque Research /Deve lopment , November 1966, P g s 38-40
T o m Green - A New Discovery fo r Controll ing the T o r a ue /Tens ion Relationshir,
Assembly Engineer ing, Ju ly 1972, P g s 42 -47
El l swor th M. Gunther - Assembly Simplif ication With Torque-Tens ion Nomograms
Assembly Engineer ing, October , 1969, P g s 36-40
Rodger Hansen - Reade r Feedback: The Turn-of - the -Nut Method (Continued)
Assembly Engineer ing, August 1967, P g s 18-22
A. G. Hopper and G. V . Thompson - S t r e s s i n P r e - loaded Bolts - Produc t Engineer ing, Sep tember 14, 1964
P g s 81-87
M. D. Hoza - The Turn-of-the-Nut Method Assembly Engineer ing, J anua ry 1967, P g s 16-19
R . R . I rv ing - Who Know's How Tight i s Tight I ron Age, October 3, 1968, P g s 85-92
G e r h a r d H. Junker - New C r i t e r i a fo r Self-Loosening of F a s t e n e r s Under Vibrat ion - SAE P a p e r 690055
Gehard Meyer , and Die te r S t re low - Sirnple D i a g r a m s Aid i n Analyzing F o r c e s in Bolted jo ints
Assembly Engineer ing, J anua ry 1972, P g s 28-33
Gehard M e y e r , . and Die te r S t re low - How to Calcula te P r e l o a d L o s s Due to P e r m a n e n t Set in Bolted Joints
Assembly Engineer ing, F e b r u a r y 1972, P g s 30 -34
I FORM 4020
L O C K N E E D * C A b l F O R 8 4 1 1 1 A C O M P A M Y A D I V I S I O N O F L O C K H E E D A I R C R A F T C O R P O R A T I O N
REVISIONS REWRT NO.
PAGE NO.
BIBLIOGRAPHY (Cont inued)
G e h a r d M e y e r , and D i e t e r S t r e l o w - How t o Ca lcu la te P r e l o a d L o s s Due to P e r m a n e n t Se t i n Bol ted J o i n t s , P a r t 2
A s s e m b l y Eng inee r ing , M a r c h 1972, P g s 28-31
W:P. McKay - P r o p e r T h r e a d Engagement by N o m o g r a m Des ign News , M a r c h 6 , 1972, P g s 60-63
C a r l C. Osgood - How E l a s t i c i t y In f luences Bol ted-Join t Des ign , Spr ing T h e o r y
Mach ine Desig-n, F e b r u a r y 24, 1972, P g s 92-95
C a r l C. 0 s good - How E l a s t i c i t y In f luences Bol ted- Jo in t Des ign , P r e l o a d and F a t i g u e Concepts
Mach ine Des ign , M a r c h 9 , 1972, P g s 104-107
E. B. P a l m e r - How L u b r i c a t i o n Affec ts T o r q u e - T e n s i o n R e l a t i o n s h i p s , A s s e m b l y and F a s t e n e r Eng inee r ing ,
S e p t e m b e r 1950, P g s 36-42
G e r h a r d S c h r e m m e r - How t o K e e p Bol ted J o i n t s Tight Mach ine Des ign , S e p t e m b e r 1972, P g s 140-145
C l a r e n c e R. S m i t h - P r e v e n t i n g F a t i g u e F a i l u r e s A s s e m b l y Eng inee r ing , P a r t s 1 t h r u 3 , M a r c h , A p r i l , May 1968, R e p r i n t
C l a r e n c e S m i t h - Reflec t io .ns , T e c h n i c a l i t i e s , and S m i t h -Kabobs - A s s e m b l y E n g i n e e r i n g , J a n u a r y 1 970, P g 33
C. F, S t e r n b u r g - F a s t e n e r P r e l o a d C o n t r o l C u r r e n t Technology - Lockheed-Ca l i fo rn ia Company R e p o r t
No. LR 22839, 22 D e c e m b e r 1969.
A . G. T o k a r c i k - T h e T o r q u e - T e n s i o n Re la t ionsh ip A s s e m b l y E n g i n e e r i n g , Oc tober 1966, R e p r i n t
FORM 402D
L O C K H E E D C A L I F O R N I A C O M P A N Y A D I V I S I O N O F L O C K H E E D A I R C R A F T C O R P O R A T I O N
REVISIONS
BIBLIOGRAPHY (Continued)
A. G. Tokarc ik - F a s t e n e r Sys tem Concept, SAE P a p e r 67 0889, Sep tember 1967
An Answer to Torque P r o b l e m s Product ion, M a r c h 1964, p g s 92-93
B a r e T i t an ium Bolt, A-286 Nut Lube Evaluat ion Standard P r e s s e d Steel , P r e c i s i o n F a s t e n e r Division Repor t No. 4976, A p r i l 28, 1972
Compara t ive Analysis of Envi ronmenta l P h y s i c a l and Mechanical Effects of Sur face Conditioning and D r y F i l m Lubricants on Ti tanium F a s t e n e r s
Voi-Shan Manufacturing Co. Engineer ing Repor t No. 459, October 21, 1569
Evaluat ion of Nut M a t e r i a l s and F in i shes fo r Use on Ti tanium Bol ts - Elas t i c Stop Nut Division,
-4merace E s n a C o r p . , Gctober 31, 1969
High Reuse P e r f o r m a n c e Ti tanium F a s t e n e r s E l a s t i c Stop Nut Division, A m e r a c e E s n a G o r p . , ER288-2929-2, Sep tember 4, 1970
How Dangerous a r e Sta t ical ly Loaded Machine M e m b e r s ? P roduc t Engineer ing, December 1971, pgs 37-39
Joint Des ign - Machine Design, Sep tember 11, 1969, pgs 12-23 I The Anatomy of a P r o b l e m : P r o p e r Tightening of Machine Sc rews - Produc t Engineer ing, October 197 1 ,
pgs 21-23
The Suitabil i ty of Var ious Coatings and Lubr ican ts f o r Use on Titanium Alloy Locknuts - Kaynar Mfg. Co . , Inc. ,
Kaylock D ~ R M L ~ ~ ~ C , November 18, 1969
FORM 4.020
LR 2504 Pg. 2 5 ,
Jh-ERDEPARThliENTAL COMMUNICATIC'N PE~O/ 5 22
TO 6.. W. I>cvis ORGN. ZONE FAC.
i DEPT.~ n-61 BWG./ 913 FLAK/ A-1 D ~ T E 7-28-.7~)
DEFT./ 77-16 CLOG./ PtAra/ A-1 EXT. 74943 ORGN. ZONE FAC.
W: Letter, BW~//~OU_-L~~I .~ , clat ed 6-39-70
Testa rre-re perforieil, as praxis&, to deternine the torque w,2..11s t o be specifiec?. for ,mbject bol t s . 3cs-ial.t~ of the t e s t s ran are a'c-trched.
If %re nay be of f'wther service, please
cc: J. I?, Jcnes J. A. Mrgan N. VerDjl Ip' R. Zelc-
@E F i le SPSP ( ~ 2 2 0 5 5 5 )
Form LAC 201
J. B. Bier5mre~ Group Lbgineer, Mechaicrja. Systms PELI*.~S md E Q x I ~ ~ ~ ;DQE~X%ILF%~
Pg . 26 ~ORQWT~~SION VEP 220555-16 m ~ o m
7u mm vs ~ ~ 0 2 0 5 - 1 6 szm P ~ 2 % XJT
b o det exmine the torque- t ension relationship of 1.0000-12 UNJF Inconel 718 bol t ad. s i lver plated ~ 2 % nuts.
XIOR: - me Ll4lll engine pylon attach bolts s are 1.0000-12 UlTJF thread size. m e bolts are ~nconel 718, part mmber 0555-16. m e mating nuts are p& nmuber ~ ~ 0 2 0 5 - 1 6 , n8de 12m ~ 2 8 6 with silver-plated threads only.. Data were noi; arvaileble i n t h i s combination of' s ize and nater ia l so that the pmper t o rwe t o provide the desired preload could be specified. Because of the cri1i;ical nature of the engi~.e a t t achen t , it was necessary- to perfom tcorque-1;asion t e s t s t o determine the proper instal lat ion torque,
19he torclple-tension t e s t s were pe,eo~s& at Valley-Todeeo, Inc. of Sylnar, California. I&. Gene lhikont ma 3 2 . Stmmt Bi~~zsds, under the direct ios of Mr, Rusis Sherman, performed the tes ts .
Test bol ts were over runs f'rm a l o t of production bol ts maneactured by V4aB1w-:Codeco. Test nuts were production nuSs disbmsed f2-an Lockkeed stock,
m%E: The IXLOZO5 aut should have silver-plated threads only. The parts dbt&ns3. f r o m stock had no plate. Ho%rever, the s q l e s used for these t e s t s were si:b-ver plated dl over a* VaUey-Todeeo, and the p M i q was rrsnwed From the nut bearing =face prior t o testing.
A &eac:ed aec t ron ics Cornpaany force washer, 1 in& I, D, ldodel Tao. 2016, was assembled on t h e bolt between hardened s tee l b t ~ s h i q s t o ac%just for the blolt grip. The force washer was aktached t o a s t ra in 5xdica;ting gauge, fStsdd P.-350, nmufactured by The isradd Co. k graph of the to rqyes t ra in relationship fo r 6 bol t of th i s s ize and mate r id hat3 previously been pswaapeh a d i s shown on Figwe I. The silver-plated nut was assmbled on t h e bol t , Zlke assembled bolt, force rasher, bushing and nu% as sab ly was then placed i n a 5 t o 1 torque a d t i p l i e s f'ixtuspe, Torq~~e i,%ms applieci in approxhately 75 fi-1% incswdeaai;~, using a P. A. Stmtev~?nt Go. torque t-mach, l~!odel irad. S-%OO (0-600 f%-1% range). Strain gauge sie&ngs were taken at each torque i n c r a a ' r ; a d recorded. 'P"he agpli& load wa;s then determined from Figure 1 . "Ie above t e s t was repeated except M I E T - ~ ~ @ lubricant tras applied t o the bol t th:read. This mssmbly w a s torqued. a d the results tabulated i n Table III and plotted on F i g w e 2.
LR 250 Page 2 Pg. 27
m e length of torque wrench am, 5 feet, made it impossible t o apply the torque continuously. fn some instances, between intervals, the wrench had t o be removed from the f ixture so&et and repositioned i n order t o Fully 8ppV the next increment of torque. This may a~cotmt for some of the erra t ic r e a s . In the first t e s t yielding in the system was observed near 1500 Ft-lbs of torque. Further application of torque produced a f a i l w e in one of the socket drive inserts i n the multiplier f x m r e . The t e s t was rerun asin&: the sane fasteners. The results of both of these t e s t s ase reported 3-13 Table I and Table I1 and plotted in Figure 2 . E"rm the graph it appears that approxinately 1250 fFt-lbs of torque i s required t o obtain 70,000 lbs preload i n the bolt when a silver-pltii;ed rrut, with no subsequent lubricant, ZB used. !Fads torque could exceed 1700 f i - lbs &er the f i r s t use i f the "'2nCt mx2" e r n e of Figure 2 was extended.
Ibe required torqie dropped drastically as ~ c ~ u l d be expected when MILT-^^& anti-seize lubricant was spplied t o the bolt thread. The curve of t h i s data Jinucettes only about 600 f i- lbs torque required for 70,000 lbs preload .in the bolt . It is e ~ e c t e d that some loss of preload would also occur i f this a.sseozb&y was reused. However, preload would probably be restored i f the bolt tms relubricated before assembly.
The engine t o pylon attach bol ts should be lubrieatecl pr ior t o a s s a b l y ~ . ~ i k h E ~ ~ ~ - 5 5 4 - & anti-seize a 9 l i e d t o bo l t %?areads. Pae assembly should be t o rqud t o 600 ft-lbs. The engineering instal lat ion clraaslintgs should be ~evimect and an instal lat ion torque, i n accordance with t h i s data, be specified.
33, above t e s t s were witnessed by the foUowing Lockheed personnel:
35x11 Jones Mike TTariDyl
Dept . 77-16 D e p t . 53-73
TABLE I
TABLE II
~~220555-16 Bare Inconel 718 B o l t - lKJ-0205-16 Sliver-Plated edt - 2nd RW (1)
(1) Socket drive sheared off af%er 1500 f"t-lbs. Test r em with s m e bolt emd nut.
Page 3
Load. I'b6X103
13.2 14.2 27.8 29.5 35 5 42.0 49 3 60.7 61.2 75 5 77-0
Load 1bxl03
20. Q 20.0 26.5 27.1 36.0 36. o 45.5 62.5 64.5 69.5 70.7 80.5 84-9 5
L& 250 Pg. 28
e seen in strain gauge.
VEP220555-16 m e mlt, Threads Coated with MIL-T-5544 Anti-Seize -
IH10205-16 Silver-Plat ed Rut
Strain Gauge Read ing &/In
Pg . 30 Pcnge 5
where T = Wrench Torque, in-lbs R = Wrench Torque ra t io (fron Table V?I of ~Nl'gb)
gbi = Beload i n bolt due t o tightening, lbs Ax = Root area of bolt, sq. in.
for 1.NKX)-12 mm:
B = 0.04993 for ~ ~ ~ ~ - 5 5 k 4 lubricaat = 0.06675 for &a~~-23398 lubricant
EJOTE: R values are for cathim plated s tee l bolts and f i t t i n g and are being used oIlly for approximation of t e s t results
s-8879) = A4156
R)i = & x 1 0 0 , ~ 0 ' p s i = 64,156 ibs or = '70,000 lbs
T = .a4993 x 64,156 64156
= 4993 in-lbs = 4.6 PC-Lbs
T = .04993 x 70,000 641%
= 54-47 in-lbs E 454 fb-lbs
T = .oG;675 x 64,156 64156
= 6675 in-lbs = 556 f i - lbs
T-T TESTS VEP220555-16 S T R A I N - ( I N . / I N . )
in bolt - s i lver plated nut
ome lube uninte'ntionally on n
Torque - F t Lbs x 20
FIGURE 2
L A
REVISIONS
I E E D C A L I F O R N I A C O M P A N Y A I R C R A F T C O R P O R A T I O N
DISTRIBUTION LIST
Permanent Holders
J. B. Bierbower V. G. Har t
. J. F. Jones V; D. Moss
K. H. Achterkirchen L. Celniker J. Hong A. W. ~ ~ a l i s u c h M. L. Kovnat
G. W, Tyree W. R. Zelenka I
D. J. Mackey L. W. Nelson
G. J. Reynolds R. F. Simenz