Laboratory Reproduction and Failure Analysis of Cracked ...Post bake Ultrasonic (One time fleet...
Transcript of Laboratory Reproduction and Failure Analysis of Cracked ...Post bake Ultrasonic (One time fleet...
1
Jere
my
B. J
acob
s&
Will
ard
L. C
astn
er
Labo
rato
ry R
epro
duct
ion
and
Failu
re A
naly
sis
of
Cra
cked
Orb
iter
Rea
ctio
n C
ontr
ol S
yste
m
Nio
bium
Thr
uste
r In
ject
ors
https://ntrs.nasa.gov/search.jsp?R=20070018135 2020-08-03T05:13:16+00:00Z
2
Pres
enta
tion
Out
line
•D
escr
iptio
n of
RC
S T
hrus
ter
•Th
rust
er/In
ject
or P
hoto
s &
Cro
ss S
ectio
ns•
Inje
ctor
Cra
ck D
escr
iptio
ns•
His
tory
of I
njec
tor C
rack
ing
•R
epro
duct
ion
of In
ject
or C
rack
ing
•B
row
nfie
ld S
peci
men
•H
ydro
fluor
ic A
cid
Test
s•S
peci
men
Loa
ding
Arr
ange
men
t•S
peci
men
#3
Res
ults
•Spe
cim
en #
5 R
esul
ts•T
est M
atrix
•K
ryto
x/B
rayc
oTe
sts
•Spe
cim
en L
oadi
ng A
rran
gem
ent
•Spe
cim
en #
13 R
esul
ts•T
est M
atrix
•C
oncl
usio
ns/R
ecom
men
datio
ns
3
Ende
avou
rSTS
-113
Lan
ding
4
RC
S Th
rust
er
5
Thru
ster
Cro
ss-S
ectio
n
6
RC
S In
ject
or
Sec
tione
d S
/N 1
20
Inje
ctor
Cro
ss S
ectio
n
7
RC
S Th
rust
er, S
/N 1
20
8
Cou
nter
bore
Cra
cks
Cou
nter
bore
loca
tions
9
Rel
ief R
adiu
s C
rack
s
Cra
ck e
xten
ding
from
relie
f ra
dius
tow
ards
aco
ustic
cav
ity
Pen
etra
ntin
dica
tion
10
RC
S Th
rust
er C
rack
ing
His
tory
•Th
ree
grou
ping
s of
cra
cked
thru
ster
s
•19
79 -
SN 1
28, 1
30, 1
32•
No
Dire
ct c
ause
of c
rack
ing
foun
d•
Cor
rect
ive
actio
ns•
Dev
elop
ed u
ltras
onic
insp
ectio
n te
chni
que
•
Acc
ompl
ishe
d on
e tim
e ul
traso
nic
insp
ectio
n of
flee
t •
Add
ed u
ltras
onic
insp
ectio
n to
man
ufac
turin
g flo
w (p
re b
ake-
out)
•C
ompl
eted
100
mis
sion
Qua
l tes
t with
SN
130
& 1
32•
1982
-SN
322
, 415
, 416
, 433
•C
rack
ing
attri
bute
d to
HF
etch
ant a
nd 6
00 F
insu
latio
n ba
ke-o
ut•
Cor
rect
ive
actio
ns
•E
limin
ate
etch
ants
from
man
ufac
turin
g pr
oces
s •
Add
ed u
ltras
onic
insp
ectio
n im
med
iate
ly a
fter b
ake-
out c
ycle
•
2004
-SN
120
•C
ount
er b
ore
crac
ks fo
und
near
new
noz
zle
EB
wel
d•
Firs
t tim
e su
ch c
rack
s fo
und,
dis
cove
red
inci
dent
ally
(pen
etra
ntin
spec
tion)
•R
elie
f rad
ius
crac
ks s
imila
r to
1979
/198
2 su
bseq
uent
ly fo
und
11
Thru
ster
Man
ufac
turin
g Ti
mel
ines
1979
1982
2004
Thru
ster
SN
128
130
Qua
ltes
t13
2Q
ualt
est
322
415
416
433
120
Hig
h us
age
Preb
ake
ultr
ason
icn/
an/
an/
a1/
26/8
2 1/
28/8
2 N
o C
rack
s fo
und
No
Cra
cks
foun
d
No
Cra
cks
foun
d
No
Cra
cks
foun
d
n/a
n/a
12/1
5/82
Cra
cked
n/a
n/a
4/29
/79
No
cra
cks
fo
und
n/a
o.k.
4/2/
04
Cra
cked
Post
bak
eU
ltras
onic
(One
tim
e fl
eet i
nsp.
af
ter 1
28 fo
und)
n/a
4/14
/79
Cra
cked
@ M
AC
4/12
/79
Cra
cked
@ M
AC
n/a
n/a
n/a
Post
bak
eU
ltras
onic
(Mfg
. Ins
p.In
itiat
ed
afte
r 322
foun
d)
n/a
n/a
n/a
2/11
/82
Cra
cked
per
Sp
ecia
l U
ltras
onic
12/1
4/82
Cra
cked
12/7
/82
Cra
cked
Post
bak
eLe
ak te
st3/
14/7
9C
rack
edo.
k.o.
k.2/
11/8
2C
rack
edn/
an/
a
Pene
tran
t Ins
pect
ion
@ W
STF
n/a
n/a
n/a
n/a
n/a
n/a
Leak
Tes
t2/
12/7
93/
1/79
11/1
5/78
1/30
/82
Torq
ue B
olts
2/13
/79
3/2/
7911
/16/
781/
30/8
2
Insu
latio
n B
ake
2/28
/79
2/7/
82
12
Labo
rato
ry R
epro
duct
ion
of In
ject
or C
rack
ing
•Tes
t Pur
pose
•Id
entif
y O
ffend
ing
Spe
cies
•Id
entif
y C
ondi
tions
for C
rack
ing
•E
stab
lish
Con
ditio
nal T
hres
hold
s•T
empe
ratu
re•S
tress
Lev
el•T
ime,
etc
.•T
est P
roto
col
•Fo
llow
ed G
uida
nce
in 1
982
CA
R•A
pply
HF
Etc
hant
to C
103
•Cov
er w
ith T
itani
um•S
tress
to 3
0 K
SI
•Hea
t to
600F
for 4
8 hr
s•L
abor
ator
y R
epro
duct
ion
of C
rack
ing
Was
Enh
ance
d•
Whe
n 19
82 C
rack
ed “B
row
nfie
ld” S
peci
men
Was
Fou
nd•
Whe
n B
row
nfie
ld F
ract
ure
Sur
face
Was
Sam
e A
s Th
rust
er’s
13
The
“Bro
wnf
ield
” Sp
ecim
en…
14
HF
Etch
antT
ests
/Spe
cim
en L
oadi
ng
Gen
eric
Tes
t Pro
toco
l:
1.C
ut &
Pre
p C
103
Test
Sam
ple
2.P
lace
Har
dnes
s In
dent
atio
ns a
t M
ax T
ensi
le S
tress
Loc
atio
n
3.C
over
With
Tita
nium
, Cla
mp,
&
App
ly C
onst
ant L
oad
(Yie
ld
Stre
ngth
/ 40
KS
I)
4.A
pply
HF
Etc
hant
to C
revi
ce
5.H
eatin
g P
rofil
e, 4
00F-
600F
for
48 H
ours
6.R
emov
e fro
m T
est,
Cle
an,
Exa
min
e U
nder
Mic
rosc
ope
/ SE
M
7.B
end
to O
pen
Cra
cks
8.E
xam
ine
Frac
ture
Sur
face
M
orph
olog
y to
Est
ablis
h Fa
ilure
M
ode
Load
= C
onst
ant
(Equ
ival
ent t
o 40
KSI
)
Varia
bles
= T
, t, H
F C
once
ntra
tion
0.75
”
S.S.
Cla
mp
σ Max
Ten
sion
Can
tilev
er T
est C
onfig
urat
ion
HF
Etch
ant
Ti 6
-4
•Sp
ecim
en D
imen
sion
s•
≈1”
X 0
.2” X
0.0
40”
•D
MA
Tes
t Equ
ipm
ent
•Tr
end
Load
, Def
lect
ion,
Tem
p, T
ime
•D
ry A
ir P
urge
C10
3H
ardn
ess
Inde
nts
15
Spec
imen
#3
–H
F +
600F
Ope
ned
Afte
r Cle
anin
g
Spec
imen
#3
–IG
Fra
ctur
e
17
Spec
imen
#5
–H
F +
600F
•3
IG C
rack
Initi
atio
n Si
tes
(Cor
resp
ond
to H
ardn
ess
Inde
nts)
18
Spec
imen
#5
–“P
opco
rn”
Nea
r Orig
inN
ear T
erm
inat
ion
19
Spec
imen
#5
–C
lean
ed a
nd B
ent
As-
Test
ed
As-
Cle
aned
As-
Ben
t
20
HF
Expo
sure
Tes
t Mat
rix
Spec
imen
#C
103
Can
tilev
er B
eam
Tes
ts (C
onst
ant L
oad)
X =
Cra
cks
1Vi
se+
Nb
etch
+ Ti
cov
er+
dry
+ 40
KSI
+ 60
0°F
+ 48
hrs
2Vi
se+
Nb
etch
+ dr
y+
Ti c
over
+ 40
KSI
+ 60
0°F
+ 48
hrs
3Vi
se+
Ti c
over
+ 40
KSI
+ N
bet
ch+
dry
+ 60
0°F
+ 48
hrs
X
4Vi
se+
Nb
cove
r+ 4
0KSI
+
Ti e
tch
+ dr
y+
600°
F+
48hr
s
5Vi
se/H
ard
+ Ti
cov
er+
40KS
I+
Nb
etch
+ dr
y+
600°
F+
48hr
sX
6Vi
se/H
ard
+ Ti
cov
er+
40KS
I+
Nb
etch
+ dr
y+
400°
F+
48hr
s
8Vi
se/H
ard
+ Ti
cov
er+
40KS
I+
Nb
etch
+ dr
y+
500°
F+
48hr
sX
(min
or)
9Vi
se/H
ard
+ Ti
cov
er+
40KS
I+
Nb
etch
+ dr
y+
600°
F+
3hrs
X
10Vi
se/H
ard
+ Ti
cov
er+
40KS
I+
Nb
etch
+ dr
y+
600°
F+
48hr
s+
70°F
+ H
2O (3
X/da
y)
+ 26
0hrs
X
11Vi
se/H
ard
+ Ti
cov
er+
40KS
I+
Nb
etch
+ dr
y +
600°
F+
168h
rsX
12Vi
se/H
ard
+ N
bco
ver+
40K
SI+
Nb
etch
+ dr
y+
600°
F+
48hr
sX
13Se
e Ta
ble
2
14H
ard
+ Ti
cov
er+
40KS
I+
air
+ +
600°
F+
48hr
s
21
Kry
tox
143A
C T
ests
•Wha
t is
Kry
tox?
•P
erflu
orop
olye
ther
(PFP
E) P
olym
er•
Als
o R
efer
red
to a
s a
Syn
thet
ic O
il•
Com
pose
d of
Car
bon,
Oxy
gen
and
Fluo
rine
•Why
Tes
t Kry
tox?
•U
sed
in T
hrus
ter M
anuf
actu
ring
•C
onta
ined
Flu
orin
e•
Orig
inal
Com
patib
ility
Tes
ts a
t 110
0F n
ot 6
00F
•X
PS
Ana
lysi
s S
how
ed P
FPE
on
Frac
ture
Sur
face
22
Kry
tox
Test
s/Sp
ecim
en L
oadi
ng
3–Po
int B
end
(Con
stan
t Def
lect
ion)
Def
lect
ion
Har
dnes
s In
dent
s (T
op &
Bot
tom
Sur
face
s)
Stai
nles
s St
eel
C10
3≈
1.0
X 0.
15 X
0.0
43
10-3
8 Sc
rew
2.0”
PFPE
Oil
(Ten
sion
Sur
face
)
3–Po
int B
end
(Con
stan
t Def
lect
ion)
Def
lect
ion
Har
dnes
s In
dent
s (T
op &
Bot
tom
Sur
face
s)
Stai
nles
s St
eel
C10
3≈
1.0
X 0.
15 X
0.0
43
10-3
8 Sc
rew
2.0”
PFPE
Oil
(Ten
sion
Sur
face
)
23
Spec
imen
#13
–K
ryto
x +
600F
24
Spec
imen
#13
–K
ryto
x +
600F
Mis
sing
Gra
ins
at C
rack
Orig
in“P
opco
rn” o
n Fr
ee S
urfa
ce +
IG
Cra
ck
25
Kry
tox
Expo
sure
Tes
t Mat
rix
Spec
imen
#C
-103
Can
tilev
er B
eam
Tes
ts (C
onst
ant L
oad)
X =
Cra
cks
13H
ardn
ess
+ Ti
cov
er+
40KS
I+
Kryt
ox+
600°
F+
48hr
sX
14Se
e Ta
ble
I
15H
ardn
ess
+ Ti
cov
er+
40KS
I+
Kryt
ox+
400°
F+
48hr
s
16H
ardn
ess
+ Ti
cov
er+
40KS
I+
Kryt
ox+
500°
F+
48hr
sX
(min
or)
17H
ardn
ess
+ Ti
cov
er+
40KS
I+
Kryt
ox+
600°
F+
96hr
sX
18H
ardn
ess
+ Ti
cov
er+
40KS
I+
Kryt
ox+
600°
F+
3hrs
X
Spec
imen
#C
-103
Thr
ee-P
oint
-Ben
d Te
sts
(Con
stan
t Def
lect
ion)
29H
ardn
ess
+ no
Ti
+ >
45KS
I +
Kryt
ox+
600°
F+
1hrs
X
30N
o in
dent
+ no
Ti
+ >
45KS
I+
Kryt
ox+
600°
F+
1hrs
31H
ardn
ess
+ no
Ti
+ >
45KS
I+
Bray
co+
600°
F+
1hrs
Spec
imen
#C
b752
Thr
ee-P
oint
-Ben
d Te
sts
(Con
stan
t Def
lect
ion)
32H
ardn
ess
+ no
Ti
+ >
45KS
I+
Bray
co+
600°
F+
23 h
rsX
26
Con
clus
ions
/ R
ecom
men
datio
ns
•Cra
cks
Suc
cess
fully
Rep
rodu
ced
in L
abor
ator
y•S
imul
tane
ous
Con
ditio
ns N
eces
sary
for C
rack
ing
•M
echa
nica
lly D
istu
rbed
/Col
d W
orke
d S
urfa
ce•
Ext
erna
lly A
pplie
d S
usta
ined
Stre
ss n
ear Y
ield
•Fl
uorin
e C
onta
inin
g Fl
uid
•S
usta
ined
Tem
pera
ture
abo
ve 4
00F
•C
rack
ing
Occ
urre
d D
urin
g M
anuf
actu
ring
•O
nly
Tim
e al
l Fou
r Con
ditio
ns a
ct S
imul
tane
ousl
y•
Elim
inat
e us
e of
Flu
orin
e w
ith N
iobi
um
•S
ame
Cra
ckin
g M
echa
nism
Ope
ratin
g in
HF
and
PFP
E F
luid
s•
Spe
cific
Cra
ckin
g M
echa
nism
not
Iden
tifie
d
27
Bac
k-U
p
28
Loca
tion
Of C
rack
s
29
Frac
ture
Fac
e of
Rel
ief R
adiu
s C
rack
30
Cle
avag
e Fr
actu
re o
n S/
N 1
20
Ope
ned
Rel
ief R
adiu
s (B
etw
een
Hol
es J
& K
)
31
Com
paris
on o
f Thr
uste
r Fai
lure
Ana
lysi
s Fi
ndin
gs
1979
1982
2004
Thru
ster
SN
128
130
132
322
415
416
433
120
YES
YES
Frac
ture
D
isco
lore
dYE
SYE
SYE
SYE
SYE
SYE
SYE
SYE
S
Cra
ckEx
tens
ion
Bey
ond
Dis
colo
ratio
n
No
NO
NO
NO
NO
NO
NO
NO
Surf
ace
Che
mis
try
F,O
,CF
F,O
,CF
FF
FF,
O,C
YES
No
serv
ice
hist
ory
YES
YES
YES
17 fl
ight
s,N
oN
o se
rvic
e hi
stor
y
YES
YES
No
serv
ice
hist
ory
Cra
ck In
itiat
ed in
M
fg.
YES
YES
YES
YES
Cra
cked
100
%In
terg
ranu
lar
YES
YES
YES
YES
Cra
ckEx
tens
ion
In
serv
ice/
Qua
l Tes
t
No
serv
ice
hist
ory
Qua
l, N
oQ
ual,
No
No
serv
ice
hist
ory
32
Dis
cuss
ion
•C
hem
ical
bre
akdo
wn
of th
e P
FPE
pol
ymer
cha
in is
a w
ell k
now
n ph
enom
ena
to th
e lu
bric
atio
n co
mm
unity
.
•Th
e m
echa
nism
tend
s to
follo
w th
ree
step
s:1.
The
met
al/o
xide
sur
face
reac
ts w
ith fl
uorin
e fro
m th
e P
FPE
to fo
rm
a Le
wis
aci
d (i.
e. N
bF3
/ NbF
5).
2. T
he L
ewis
aci
d ca
taly
zes
the
clea
vage
of t
he p
olym
er c
hain
.3.
The
bro
ken
poly
mer
cha
in c
an re
act w
ith w
ater
to fo
rm a
car
boxy
lic a
cid
term
inat
ed g
roup
rele
asin
g hy
drof
luor
ic a
cid.
Che
mic
al B
reak
dow
n of
Kry
tox
PFPE
Pol
ymer
Kry
tox
(Per
fluor
opol
yeth
er)
CF 3
CF 3
–CF 2
–CF 2
–O —
CF 2
–CF 2
–O —
CF 2
–CF 3
Fm Le
wis
Aci
d
STEP
1
STEP
2
STEP
3
33
Inje
ctor
Cra
ck F
light
Rat
iona
le R
oad-
Map