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NP
L R
eport
MA
TC
(A)9
0
Ox
ida
tio
n o
f A
llo
ys
in
Ste
am
En
vir
on
me
nts
- A
Revie
w
A F
ry,
S O
sgerb
y,
M W
right
Se
pte
mb
er
20
02
NP
L R
epor
t M
AT
C(A
)90
i
Oxi
dati
on o
f A
lloy
s in
Ste
am E
nvir
onm
ents
– A
Rev
iew
A
Fry
, S O
sger
by, M
Wri
ght
NP
L M
ater
ials
Cen
tre
A
BS
TR
AC
T
Tra
diti
onal
ly
mat
eria
ls
desi
gned
fo
r us
e at
hi
gh
tem
pera
ture
ha
ve
been
de
velo
ped
prim
aril
y fo
r th
eir
mec
hani
cal
prop
erti
es b
ut t
here
is
now
a g
row
ing
real
isat
ion
that
ox
idat
ion
may
li
mit
li
feti
me.
The
pu
rpos
e of
th
is
repo
rt
is
to
revi
ew
exis
ting
in
form
atio
n re
gard
ing
oxid
atio
n of
al
loys
, w
hich
ar
e in
tend
ed
for
use
at
high
te
mpe
ratu
res,
und
er a
tmos
pher
es c
onta
inin
g st
eam
or
high
wat
er v
apou
r co
nten
t an
d to
id
enti
fy a
reas
whe
re m
ore
unde
rsta
ndin
g is
req
uire
d.
ii
NP
L R
epor
t M
AT
C(A
)90
iii
Cro
wn
Cop
yrig
ht 2
002
Rep
rodu
ced
by P
erm
issi
on o
f th
e C
ontr
olle
r of
HM
SO
ISS
N 1
473-
2734
Nat
iona
l P
hysi
cal
Lab
orat
ory
Que
ens
Roa
d, T
eddi
ngto
n, M
iddl
esex
, TW
11 0
LW
Ext
ract
s fr
om t
his
repo
rt m
ay b
e re
prod
uced
pro
vide
d th
e so
urce
is
ackn
owle
dged
and
th
e ex
trac
t is
not
tak
en o
ut o
f co
ntex
t.
App
rove
d on
beh
alf
of t
he M
anag
ing
Dir
ecto
r, N
PL
by
Dr
Col
in L
ea, H
ead,
NP
L M
ater
ials
Cen
tre
iv
NP
L R
epor
t M
AT
C(A
)90
v C
ON
TE
NT
S
1 In
trod
ucti
on...
......
......
......
......
......
......
......
......
......
......
......
......
......
......
......
......
......
......
......
...1
2 T
he I
nflu
ence
of
Chr
omiu
m C
onte
nt...
......
......
......
......
......
......
......
......
......
......
......
......
......
1 3
Low
All
oy F
erri
tic
Ste
els.
......
......
......
......
......
......
......
......
......
......
......
......
......
......
......
......
..6
4 9-
12%
Cr
Mar
tens
itic
Ste
els
......
......
......
......
......
......
......
......
......
......
......
......
......
......
......
..12
5
Aus
teni
tic
Ste
els.
......
......
......
......
......
......
......
......
......
......
......
......
......
......
......
......
......
......
..17
6
Ni-
and
Co-
base
d al
loys
......
......
......
......
......
......
......
......
......
......
......
......
......
......
......
......
...24
7
Mec
hani
sms
of O
xida
tion
Und
er E
nvir
onm
ents
Con
tain
ing
Wat
er V
apou
r....
......
......
...28
7.
1 D
isso
ciat
ion
Mec
hani
sm...
......
......
......
......
......
......
......
......
......
......
......
......
......
......
...28
7.
2 O
xida
nt-g
as P
enet
rati
on M
echa
nism
......
......
......
......
......
......
......
......
......
......
......
.....
30
7.3
For
mat
ion
and
Vol
atil
isat
ion
of F
e(O
H) 2
......
......
......
......
......
......
......
......
......
......
....3
0 7.
4 F
orm
atio
n an
d V
olat
ilis
atio
n of
CrO
2(O
H) 2
......
......
......
......
......
......
......
......
......
......
31
7.5
Cha
nges
in
the
Oxi
de D
efec
t S
truc
ture
via
Pro
ton
Dis
solu
tion
......
......
......
......
......
.31
8 D
iscu
ssio
n an
d C
oncl
usio
ns...
......
......
......
......
......
......
......
......
......
......
......
......
......
......
.....
33
9 R
efer
ence
s....
......
......
......
......
......
......
......
......
......
......
......
......
......
......
......
......
......
......
......
..35
NP
L R
epor
t M
AT
C(A
)90
Pag
e 1
of 3
9
1
Intr
od
uct
ion
Dur
ing
serv
ice
in h
igh
tem
pera
ture
pla
nt, t
ubin
g, p
ipin
g an
d he
ader
s in
boi
lers
are
exp
osed
to
stea
m a
t hi
gh p
ress
ure
flow
ing
at h
igh
rate
s an
d of
ten
in t
he p
rese
nce
of h
eat
flux
. S
imil
arly
co
mpo
nent
s in
ste
am t
urbi
nes
are
expo
sed
to h
igh-
pres
sure
ste
am a
tmos
pher
es.
Ser
vice
li
feti
mes
of
th
ese
com
pone
nts
may
be
li
mit
ed
by
cree
p,
fati
gue
or
oxid
atio
n.
Tra
diti
onal
ly m
ater
ials
des
igne
d fo
r us
e at
hig
h te
mpe
ratu
re h
ave
been
dev
elop
ed p
rim
aril
y fo
r th
eir
mec
hani
cal
prop
erti
es b
ut t
here
is
now
a g
row
ing
real
isat
ion
that
oxi
dati
on m
ay l
imit
li
feti
me,
eit
her
dire
ctly
thr
ough
met
al w
asta
ge o
r in
dire
ctly
thr
ough
rai
sing
loc
al t
empe
ratu
res
(and
con
sequ
entl
y re
duci
ng c
reep
-con
trol
led
life
tim
es)
due
to t
he l
ower
the
rmal
con
duct
ivit
y of
the
oxi
de s
cale
. T
he p
urpo
se o
f th
is r
epor
t is
to
revi
ew e
xist
ing
info
rmat
ion
rega
rdin
g ox
idat
ion
of a
lloy
s,
whi
ch a
re i
nten
ded
for
use
at h
igh
tem
pera
ture
s, u
nder
atm
osph
eres
con
tain
ing
stea
m o
r hi
gh
wat
er v
apou
r co
nten
t an
d to
ide
ntif
y ar
eas
whe
re g
reat
er u
nder
stan
ding
is
requ
ired
. O
ne o
f th
e di
ffic
ulti
es e
ncou
nter
ed i
n co
mpa
ring
tes
t re
sult
s w
ithi
n th
e li
tera
ture
is
ensu
ring
tha
t th
e co
ndit
ions
of
the
expo
sure
s ar
e si
mil
ar.
In
man
y ca
ses
the
cond
itio
ns o
f th
e ex
posu
re a
nd/o
r th
e w
ater
che
mis
try
wer
e no
t st
ated
, th
is i
nfor
mat
ion
has
been
inc
lude
d in
thi
s re
view
whe
re
avai
labl
e.
2
Th
e In
flu
ence
of
Ch
rom
ium
Co
nte
nt
The
mos
t si
gnif
ican
t im
prov
emen
ts i
n ox
idat
ion
resi
stan
ce a
re a
chie
ved
by c
hang
ing
the
inhe
rent
nat
ure
of t
he p
rote
ctiv
e ox
ide
scal
e. O
ne o
f th
e m
ost
dram
atic
dem
onst
rati
ons
of t
his
mec
hani
sm i
s th
e in
flue
nce
of c
hrom
ium
add
itio
ns t
o ir
on-b
ase
allo
ys.
Dur
ing
oxid
atio
n,
carb
on
stee
ls
form
a
scal
e co
nsis
ting
of
on
e or
m
ore
laye
rs
of
wus
tite
, ha
emat
ite
and
mag
neti
te d
epen
ding
upo
n th
e sp
ecif
ic o
xida
tion
con
diti
ons.
T
he a
ddit
ion
of c
hrom
ium
to
the
allo
ys f
irst
ly c
hang
es t
he s
cale
suc
h th
at t
he i
nner
lay
er (
mag
neti
te i
n pl
ain
carb
on s
teel
s)
is a
n ir
on-c
hrom
ium
spi
nel
in l
ow a
lloy
fer
riti
c (u
p to
3%
Cr)
or
mar
tens
itic
(9-
12%
Cr)
ste
els.
F
urth
er i
ncre
ases
in
chro
miu
m w
ill
even
tual
ly l
ead
to t
he f
orm
atio
n of
chr
omia
, e.
g. i
n au
sten
itic
sta
inle
ss s
teel
s.
The
eff
ect
of i
ncre
asin
g th
e ch
rom
ium
con
tent
in
ferr
itic
ste
els
has
been
dem
onst
rate
d in
bot
h la
bora
tory
and
ser
vice
exp
osur
es.
Sol
berg
et
al 1 d
emon
stra
ted
a sy
stem
atic
dec
reas
e in
met
al
loss
wit
h in
crea
sing
chr
omiu
m c
onte
nt i
n sh
ort-
term
lab
orat
ory
test
s at
593
°C
. T
heir
dat
a ar
e pr
esen
ted
in F
igur
e 1.
S
imil
arly
Ebe
rle
et a
l 2 d
emon
stra
ted
(see
Tab
le I
) a
sim
ilar
tre
nd i
n m
ater
ial
that
had
bee
n w
ithd
raw
n fr
om s
ervi
ce a
fter
360
00 h
ours
at
554
°C /
160
atm
.
NP
L R
epor
t M
AT
C(A
)90
Pag
e 2
of 3
9
F
igu
re 1
Co
rro
sio
n o
f st
eel
ba
rs i
n c
on
tact
wit
h s
tea
m a
t 5
93
°C
fo
r 20
0, 5
00
, 100
0 a
nd
200
0 h
(aft
er
So
lber
g e
t al
1)
Ta
ble
I M
eta
llo
gra
ph
ica
lly
mea
sure
d s
cale
th
ick
nes
s o
n e
xp
osu
re t
o s
tea
m a
t 554
°C
/160
atm
fo
r 36
000
h
(aft
er E
ber
le e
t al
2)
Mat
eria
l In
ner
scal
e,
m*
Out
er s
cale
, m
* T
otal
thi
ckne
ss,
m*
Tot
al t
hick
ness
ra
nge,
m
# S
A-2
10 C
-ste
el
90
70
160
125
– 16
0 ½
Mo
80
70
150
125
– 15
0 ½
Cr
– ½
Mo
70
55
125
125
– 16
5 1¼
Cr
– ½
Mo
75
60
13
5 13
5 –
165
2¼ C
r –
½ M
o
75
60
135
125
– 14
5 5
Cr
– ½
Mo
70
50
120
110
– 15
0 7
Cr
– ½
Mo
65
55
120
120
– 12
5 9
Cr
– 1M
o 65
55
12
0 12
0 –
145
* M
easu
red
at o
ne l
ocat
ion
# Ran
ge o
f m
easu
rem
ents
H
eier
man
n et
al
3 hav
e al
so s
how
n th
at t
here
is
a tr
end
for
the
high
er C
r-co
ntai
ning
ste
els
to
prod
uce
thin
ner
scal
es:
160
and
260
m s
cale
s at
560
°C
for
12
and
9% C
r an
d 29
0 an
d 51
0 m
sca
les
at 6
00 °
C f
or 1
2 an
d 9%
Cr
ferr
itic
ste
els
resp
ecti
vely
aft
er 2
0000
0 ho
urs
expo
sure
. T
hus
the
mor
e C
r an
all
oy c
onta
ins
the
bett
er i
t ca
n pr
otec
t it
self
fro
m o
xida
tion
, an
d th
eref
ore
allo
ys
wit
h hi
gh
Cr
are
usua
lly
used
in
co
rros
ive
envi
ronm
ents
.
The
im
prov
emen
t in
ste
am o
xida
tion
res
ista
nce
of t
he 9
-12C
r m
ater
ials
ove
r th
e lo
w a
lloy
fer
riti
c st
eels
is
dem
onst
rate
d in
Fig
ure
2 4 .
At
560
°C t
he r
ate
of s
cale
gro
wth
on
9%C
r st
eels
is
half
th
at o
n 2%
Cr
mat
eria
l. I
ncre
asin
g th
e ch
rom
ium
con
tent
to
12%
pro
duce
s an
othe
r fa
ctor
of
two
impr
ovem
ent.
NP
L R
epor
t M
AT
C(A
)90
Pag
e 3
of 3
9
Thi
s im
prov
ed p
rote
ctio
n ca
n al
so b
e se
en i
n F
igur
e 3,
whi
ch s
how
s th
e ox
idat
ion
of T
22,
T23
, T
P34
7, T
91 a
nd T
92 i
n fl
owin
g pu
re w
ater
vap
our
at 6
50°C
5 . I
n th
is i
nsta
nce
the
sam
ples
wer
e hu
ng o
n a
kant
halm
ade
supp
ort
fixe
d on
a c
orun
dum
bas
ket,
whi
ch w
as t
hen
plac
ed i
nto
the
mul
lite
tub
es i
nsid
e a
tubu
lar
furn
ace.
T
he s
team
was
pro
duce
d by
ebu
llit
ion
of d
eion
ised
wat
er.
The
cor
rosi
on r
ates
of
the
stee
ls w
ere
dete
rmin
ed b
y m
ass
chan
ge
mea
sure
men
ts p
rior
to
and
afte
r ex
posu
re a
nd d
esca
ling
by
etch
ing
in s
odiu
m h
ydro
xide
m
elte
d at
450
°C
4 .
Man
ning
and
Met
calf
e 6 h
ave
also
dem
onst
rate
d th
is i
mpr
ovem
ent
whe
n th
ey c
ompa
red
the
para
boli
c ra
te
cons
tant
s of
2¼
Cr1
Mo
wit
h 9C
r1M
o an
d 12
Cr
ferr
itic
st
eels
ov
er
the
800
700
600
500
400
300
200
100 0
0 2
0 40 60
8
0 100 120 140 160 180 2
00
BORE SCALE THICKNESS (m)
EX
PO
SU
RE
TIM
E (10
3 h
ours
)1%
& 2
% C
r @
600
oC
1%
& 2
% C
r @
560
oC
9%
Cr
@ 560
oC
9%
Cr
@ 600
oC
12%
Cr
@ 600
oC
12%
Cr
@ 560
oC
Fig
ure
2 B
ore
ox
ide
sca
le t
hic
kn
ess
as
a f
un
ctio
n o
f o
per
ati
ng
tim
e an
d t
emp
eratu
re f
or
ferr
itic
(1-2
%C
r) a
nd
ma
rten
siti
c (9
-12
%C
r) s
teel
s (a
fter
Ref
. 4
)
0
100
200
300
400
500
600
700
800
01000
2000
3000
4000
5000
6000
Tim
e, h
T22
T23
TP
347
T91
T92
Fig
ure
3 O
xid
ati
on
in
flo
win
g p
ure
wa
ter
va
po
ur
at
650 °
C (
aft
er R
ef 5
)
NP
L R
epor
t M
AT
C(A
)90
Pag
e 4
of 3
9
tem
pera
ture
ran
ge 5
00 –
700
°C
. A
sig
nifi
cant
red
ucti
on i
n th
e pa
rabo
lic
rate
con
stan
t w
ith
incr
easi
ng c
hrom
ium
con
tent
fro
m 2
¼ t
o 9%
is
seen
at
the
high
er e
nd o
f th
e te
mpe
ratu
re
rang
e bu
t th
e di
ffer
ence
bet
wee
n th
e tw
o al
loy
clas
ses
is l
ess
mar
ked
at l
ower
tem
pera
ture
s.
How
ever
, th
ere
also
exi
sts
a bo
dy o
f co
ntra
dict
ory
evid
ence
of
oxid
atio
n be
havi
our
of t
he
2¼C
r-1
Mo
stee
l an
d th
e 9C
r.
The
sm
all
impr
ovem
ent
in o
xida
tion
pro
pert
ies
brou
ght
abou
t by
inc
reas
ing
the
Cr
cont
ent
from
2¼
to
valu
es c
hara
cter
isti
c of
the
9%
Cr
allo
ys w
as
high
ligh
ted
by G
ries
s an
d M
axw
ell
7 who
cla
imed
tha
t fr
om p
urel
y a
stea
m o
xida
tion
st
andp
oint
the
re w
ere
no s
igni
fica
nt d
iffe
renc
es i
n th
e co
rros
ion
rate
s. T
his
obse
rvat
ion
cam
e fr
om w
ork
they
con
duct
ed,
whe
re s
elec
ted
allo
ys w
ere
expo
sed
to p
lant
ste
am,
from
the
B
arto
w P
ower
Pla
nt o
f th
e F
lori
da P
ower
Cor
pora
tion
. S
ampl
es o
f a
2¼C
r-1
Mo
stee
l w
ere
prep
ared
fro
m m
ill-
anne
aled
pla
te.
A s
elec
tion
of
thes
e w
ere
anne
aled
(73
2 °C
for
2 h
and
th
en f
urna
ce c
oole
d) w
hils
t th
e ot
hers
wer
e pi
ckle
d.
No
sign
ific
ant
diff
eren
ces
aros
e fr
om
the
diff
eren
t su
rfac
e tr
eatm
ents
as
show
n in
Fig
ure
4, w
here
the
sim
ilar
oxi
dati
on b
ehav
iour
of
the
9C
r st
eel
can
also
be
seen
. T
he o
xida
tion
kin
etic
s in
itia
lly
foll
ow a
par
abol
ic r
ate
law
, un
til
arou
nd 5
000
hour
s, a
t w
hich
poi
nt t
he o
xida
tion
rat
e be
com
es m
ore
line
ar.
It
app
ears
tha
t th
e le
vel
of b
enef
it a
risi
ng f
rom
inc
reas
ed c
hrom
ium
con
tent
is
not
cons
tant
bu
t is
dep
enda
nt o
n th
e m
oist
ure
cont
ent
of t
he o
xidi
sing
atm
osph
ere.
T
o il
lust
rate
thi
s po
int
whe
n co
mpa
ring
the
oxi
dati
on i
n st
eam
of
the
low
Cr
cont
aini
ng a
lloy
s T
22 a
nd T
23 t
o th
e hi
gher
Cr
cont
aini
ng f
erri
tic
stee
ls i
t ha
s be
en r
epor
ted
by G
ambi
er 8 t
hat
the
corr
osio
n ra
tes
of t
he 9
% C
r st
eels
wer
e on
ly a
bout
3 t
imes
low
er t
han
thos
e of
the
2¼
% C
r st
eels
. T
hese
re
sult
s cl
earl
y de
mon
stra
te t
he d
elet
erio
us e
ffec
t of
wat
er v
apou
r si
nce
the
corr
osio
n ra
te i
n ai
r is
usu
ally
60
– 70
tim
es l
ower
for
9C
r st
eels
tha
n fo
r 2¼
Cr
stee
ls.
Thi
s re
duct
ion
of t
he
favo
urab
le e
ffec
t of
Cr
in s
team
com
pare
d to
in
air
has
been
att
ribu
ted
to c
hang
es i
n th
e m
orph
olog
y of
the
oxi
de s
cale
s de
velo
ped
in s
team
env
iron
men
ts.
Lep
ingl
e 5 s
how
ed t
hat
02468
10
12
14
16
05000
10000
15000
20000
25000
30000
Tim
e,
h
482°C
Gro
und
482°C
Anneale
d
482°C
Pic
kle
d
538°C
Gro
und
538°C
Anneale
d
538°C
Pic
kle
d
9C
r 482°C
9C
r 538°C
Fig
ure
4 2
¼C
r1M
o a
nd
9C
r st
eels
ex
po
sed
to
su
per
hea
ted
pla
nt
stea
m (
aft
er R
ef. 7
)
NP
L R
epor
t M
AT
C(A
)90
Pag
e 5
of 3
9
wit
hin
such
oxi
de s
cale
s th
ere
exis
ted
a la
rge
num
ber
of m
acro
scop
ic d
efec
ts,
such
as
pore
s,
crac
ks e
tc.
Whi
lst
it i
s ev
iden
t th
at w
ater
vap
our
does
inc
reas
e th
e ox
idat
ion
kine
tics
it
is a
lso
true
tha
t th
e pr
esen
ce o
f hi
gh l
evel
s of
Cr
in t
he a
lloy
doe
s st
ill
impa
rt s
ome
enha
nced
pro
tect
ion.
In t
he c
ase
of a
lloy
s w
ith
Cr
cont
ent
over
12%
ben
efit
s in
ste
am o
xida
tion
res
ista
nce
have
ag
ain
been
obs
erve
d fr
om i
ncre
ases
in
the
Cr
cont
ent.
T
ests
hav
e sh
own
that
inc
reas
ing
the
Cr
cont
ent
from
12
to 1
8% i
ncre
ased
the
dur
atio
n of
the
pro
tect
ive
stag
es o
f so
me
allo
ys f
rom
1
hour
to
mor
e th
an 2
5 ho
urs.
In
stu
dies
by
Tav
ast
9 and
Ots
uka
and
Fuj
ikaw
a 10
it
was
co
nclu
ded
that
if
the
Cr
cont
ent
was
ove
r 25
% (
Ots
uka
quot
es 2
2%),
the
n a
cont
inuo
us
chro
mia
lay
er q
uick
ly f
orm
s at
the
met
al-m
etal
oxi
de in
terf
ace,
slo
win
g do
wn
the
diff
usio
n of
ir
on t
o fo
rm m
agne
tite
at
the
gas-
met
al i
nter
face
. T
his
is a
gen
eral
rul
e an
d th
ere
wil
l be
ex
cept
ions
. F
or e
xam
ple,
in
a co
mpa
rati
ve s
tudy
the
aus
teni
tic
stee
l T
P34
7 w
as f
ound
to
have
med
iocr
e co
rros
ion
resi
stan
ce, d
espi
te i
ts h
igh
leve
l of
Cr
cont
ent
5 . T
he r
elat
ivel
y po
or
beha
viou
r w
as
attr
ibut
ed
to
corr
osio
n pr
oduc
t sc
alin
g ph
enom
ena
and
the
non-
unif
orm
he
alin
g of
the
chr
omia
lay
er d
urin
g th
e te
st (
this
has
als
o be
en o
bser
ved
by A
rman
et 11
, M
ontg
omer
y 12
and
Ots
uka
10).
T
his
may
sug
gest
tha
t th
ere
is a
lim
it t
o th
e m
axim
um
amou
nt o
f C
r th
at i
s be
nefi
cial
in
term
s of
sca
le a
dher
ence
. F
igur
e 5
show
s th
e m
etal
los
s ra
te f
or a
lloy
s w
ith
diff
erin
g am
ount
s of
Cr.
T
he d
ata
show
how
the
am
ount
of
met
al l
oss
decr
ease
s w
ith
incr
easi
ng C
r co
nten
t an
d ap
proa
ches
a p
late
au l
evel
, thu
s il
lust
rati
ng a
n up
per
lim
it t
o th
e be
nefi
ts o
f C
r ad
diti
ons.
Fig
ure
5 M
etal
loss
ra
te a
s a f
un
ctio
n o
f ch
rom
ium
co
nte
nt
for
sele
cted
mate
rials
un
der
sim
ula
ted
fir
esid
e co
rrosi
on
co
nd
itio
ns
(aft
er R
ef. 5)
NP
L R
epor
t M
AT
C(A
)90
Pag
e 6
of 3
9
3
Lo
w A
llo
y F
erri
tic
Ste
els
Low
all
oy f
erri
tic
stee
ls a
re m
ost
wid
ely
used
in
pres
suri
sed
appl
icat
ions
in
boil
ers
fire
d by
fo
ssil
fue
ls a
nd a
lso
in H
eat
Rec
over
y S
team
Gen
erat
ors
(HR
SG
’s).
S
peci
fica
lly
thes
e ar
e tu
bing
all
oys
that
are
use
d pa
rtic
ular
ly i
n th
e co
oler
sec
tion
s of
sup
erhe
ater
s an
d re
heat
ers
and
also
for
the
wat
erw
alls
in
the
tem
pera
ture
ran
ge w
here
mil
d st
eel
beco
mes
too
sus
cept
ible
to
cre
ep.
The
se a
lloy
s ar
e al
so u
sed
in t
hick
-sec
tion
com
pone
nts
such
as
head
ers
and
stea
m
pipe
s.
Com
mon
ly t
he k
ey r
equi
rem
ents
tha
t th
is c
lass
of
mat
eria
l m
ust
exhi
bit
are
G
ood
tens
ile
stre
ngth
(l2
0 M
Pa)
at
tem
pera
ture
s up
to
450
°C
Cre
ep s
tren
gth
at t
empe
ratu
res
up t
o 55
0 °C (
T22
, T23
) E
xcel
lent
wel
dabi
lity
wit
h no
req
uire
men
t fo
r po
st-w
eld
heat
tre
atm
ent
Res
ista
nce
to s
team
oxi
dati
on
For
the
pur
pose
of
this
rev
iew
the
mos
t pe
rtin
ent
of t
he a
bove
req
uire
men
ts i
s th
e re
sist
ance
to
ste
am o
xida
tion
. T
hese
mat
eria
ls d
o ha
ve l
imit
ed r
esis
tanc
e to
ste
am o
xida
tion
, an
d im
prov
ing
this
res
ista
nce
wou
ld r
esul
t in
enh
ance
d he
at t
rans
fer
and
incr
ease
d op
erat
ing
tem
pera
ture
, th
ereb
y co
ntri
buti
ng t
o in
crea
sed
plan
t ef
fici
ency
wit
h li
ttle
inc
reas
e in
cos
t.
Tab
le I
I sh
ows
the
com
posi
tion
of
som
e co
mm
on l
ow a
lloy
1-3
% C
r st
eels
, to
geth
er w
ith
com
mon
ly u
sed
alte
rnat
ive
nom
encl
atur
e of
the
se a
lloy
s.
Ta
ble
II
Co
mp
osi
tio
n o
f L
ow
All
oy 1
-3%
Cr
Ste
els
The
sca
le f
orm
ed d
urin
g st
eam
oxi
dati
on o
f lo
w a
lloy
ste
els
has
thre
e di
stin
ct r
egio
ns w
hen
cros
s-se
ctio
ned.
The
se c
ompr
ise
a th
ick
com
pact
out
er l
ayer
, a
subs
cale
reg
ion
cons
isti
ng o
f ex
tens
ive
inte
rnal
oxi
de p
reci
pita
te f
orm
atio
n m
ostl
y al
ong
the
grai
n bo
unda
ries
, an
d a
thin
la
yer
betw
een
the
oute
r la
yer
and
the
subs
cale
. I
t is
cla
imed
tha
t a
crit
ical
bal
ance
of
the
sele
ctiv
ely
oxid
ised
met
al,
the
oxid
ant
spec
ies
and
the
grow
th r
ate
of t
he e
xter
nal
scal
e go
vern
the
ext
ent
of t
he i
nter
nal
oxid
e pr
ecip
itat
ion
and
subs
cale
for
mat
ion
13.
The
re i
s a
dist
inct
dif
fere
nce
in t
he s
truc
ture
and
mor
phol
ogy
of t
he o
xide
sca
les
form
ed
unde
r ‘d
ry’
air
oxid
atio
n an
d st
eam
oxi
dati
on.
In t
erm
s of
the
mor
phol
ogy
of t
he o
xide
sca
les
a re
cent
stu
dy c
ondu
cted
by
Ram
an 14
, in
whi
ch s
peci
men
s w
ere
oxid
ized
at
600
°C i
n a
Co
mp
osi
tio
n, w
t%
All
oy
A
lter
nati
ve
No
men
clatu
re
C
Mn
P
S
S
i C
r M
o
V
N
Nb
W
B
ppm
A
l
Min
0.
05
0.3
0.5
1.0
0.44
G
rade
11
P
11/T
11/1
3CrM
o 4
4 M
ax
0.15
0.
6 0.
025
0.02
5 1.
0 1.
5 0.
65
Min
0.
05
0.3
1.
9 0.
05
Gra
de
22
P22
/T22
/ 10
CrM
o 9
10
Max
0.
15
0.6
0.02
5 0.
025
0.5
2.6
1.13
M
in
0.04
0.
1
1.9
0.05
0.
2
0.02
1.
45
5
G
rade
23
P
23/T
23/H
CM
2S
Max
0.
1 0.
6 0.
03
0.01
0.
5 2.
6 0.
3 0.
3 0.
03
0.08
1.
75
6
0.03
M
in
0.05
0.
3
0.
15
2.2
0.9
0.2
15
Gra
de
24
T24
/7C
rMoV
TiB
10
-10
Max
0.
10
0.7
0.02
0.
01
0.45
2.
6 1.
10
0.3
0.01
2
70
0.
02
1CrM
oV
0.25
0.
8 0.
01
0.02
0.
2 1.
0 1.
0 0.
3 0.
004
0.
01
NP
L R
epor
t M
AT
C(A
)90
Pag
e 7
of 3
9
mix
ture
of
stea
m a
nd n
itro
gen,
rep
orte
d th
at t
he s
cale
s de
velo
ped
duri
ng s
team
oxi
dati
on o
n 2¼
Cr-
1Mo
stee
l co
nsis
ted
of f
acet
ed o
xide
gra
ins,
whi
lst
the
mor
phol
ogy
of t
he a
ir-o
xidi
sed
spec
imen
s w
ere
repo
rted
to
be f
eatu
rele
ss.
The
str
uctu
re o
f th
e sc
ales
on
the
stea
m o
xidi
sed
spec
imen
s, i
t w
as n
oted
, w
ere
free
fro
m s
urfa
ce p
ores
and
the
oxi
de g
rain
s w
ere
clos
ely
com
pact
ed t
o ea
ch o
ther
. T
his
is d
isti
nctl
y di
ffer
ent
to t
he p
orou
s ou
ter
scal
es o
bser
ved
unde
r ai
r-ox
idat
ion.
G
ener
al o
bser
vati
ons
have
ind
icat
ed t
hat
the
oxid
e sc
ale,
whi
ch f
orm
s on
the
ste
am s
ide
surf
ace
of c
arbo
n st
eel
boil
er t
ubes
, is
gen
eral
ly f
ound
to
cons
ist
of a
mul
tila
yere
d sc
ale
15.
The
com
posi
tion
of
the
scal
es i
s pr
edom
inan
tly
mag
neti
te a
nd w
usti
te (
Fe 3
O4
and
FeO
re
spec
tive
ly);
how
ever
the
re i
s al
so e
vide
nce
in X
RD
pat
tern
s of
the
pre
senc
e of
an
iron
-ch
rom
ium
sp
inel
ox
ide
(FeC
r 2O
4).
M
ore
spec
ific
ob
serv
atio
ns
have
in
dica
ted
that
at
te
mpe
ratu
res
belo
w 5
60 °
C a
sca
le c
onsi
stin
g of
mag
neti
te (
Fe 3
O4)
and
hae
mat
ite
(Fe 2
O3)
is
foun
d.
At
high
er t
empe
ratu
res
an a
ddit
iona
l in
ner
laye
r of
wus
tite
(F
eO)
may
be
pres
ent.
If
th
e tu
bing
in
ques
tion
is
allo
yed
then
a s
pine
l ox
ide
(Fe,
Cr,
Mo)
3O4
wil
l fo
rm a
s th
e ox
ide
grow
s in
war
d ac
ross
the
tub
e w
all 15
. T
hese
for
m a
s fo
llow
s:
sg
sF
eOO
Fe
22
sg
sO
Fe
OF
eO4
32
6 s
gs
OF
eO
OF
e3
22
43
64
Cur
rent
und
erst
andi
ng h
as i
t th
at t
he w
usti
te f
orm
atio
n te
mpe
ratu
re i
s as
sum
ed t
o be
a
cons
tant
of
560
°C,
inde
pend
ent
of t
he a
lloy
in
ques
tion
. In
wor
k co
nduc
ted
by A
rízt
egui
et
al
16 i
soth
erm
al a
nd n
on-i
soth
erm
al t
ests
wer
e co
nduc
ted
on 2
¼C
r-1M
o st
eel
(T22
) th
at
conf
irm
the
abo
ve o
bser
vati
ons.
T
hey
foun
d th
at i
n is
othe
rmal
tes
ts i
n th
e te
mpe
ratu
re r
ange
of
550
to
700
°C o
ver
expo
sure
per
iods
of
up t
o 56
day
s, t
hat
mag
neti
te w
as t
he m
ost
stab
le
oxid
e at
the
low
er t
empe
ratu
res.
The
ir o
bser
vati
ons
are
pres
ente
d in
Tab
le I
II.
Tab
le I
II O
xid
e p
rod
uct
s p
rese
nt
in t
he
oxid
e sc
ale
s fo
rmed
aft
er i
soth
erm
al
oxid
ati
on
tre
atm
ents
(a
fter
Ref
. 16)
Tem
per
atu
re
Ex
po
sure
s ti
me
(da
ys)
550 °
C
600 °
C
625 °
C
650 °
C
7 M
+H
M
/W
M
W/M
+W
14
M
+H
M
M
+(W
) /
28
M+
H
M
M+
W
M+
W
56
M
M
M+
W
/ M
– m
agne
tite
, H –
hae
mat
ite,
W –
wus
tite
. In
the
exp
erim
ents
per
form
ed b
y A
rízt
egui
et
al
16 a
con
stan
t fl
ux o
f hi
gh p
urit
y ar
gon
was
us
ed t
o ca
rry
the
stea
m t
hrou
gh t
hree
con
duit
s.
The
fir
st f
ed i
nto
a “r
efer
ence
tub
e” i
n th
e fu
rnac
e, i
n w
hich
the
sam
ple
was
exp
osed
to
high
tem
pera
ture
s in
the
abs
ence
of
stea
m.
The
re
mai
ning
tw
o id
enti
cal
cond
uits
flo
wed
thr
ough
a w
ater
fla
sk b
efor
e re
achi
ng t
he f
urna
ce
ther
eby
prod
ucin
g an
Arg
on /
ste
am m
ixtu
re.
Und
er i
soth
erm
al c
ondi
tion
s th
e ox
idat
ion
kine
tics
not
sur
pris
ingl
y fo
llow
ed a
par
abol
ic r
ate
law
, w
ith
calc
ulat
ed a
ctiv
atio
n en
ergy
of
oxid
atio
n ca
lcul
ated
fro
m t
he s
cale
thi
ckne
ss o
f 32
4 kJ
mol
-1 (
308
kJ m
ol-1
fro
m w
eigh
t ga
in d
ata)
, th
is v
alue
is
repo
rted
to
agre
e w
ell
wit
h
NP
L R
epor
t M
AT
C(A
)90
Pag
e 8
of 3
9
othe
r do
cum
ente
d va
lues
and
it
is c
laim
ed t
o be
con
sist
ent
wit
h a
reac
tion
con
trol
led
by
diff
usio
n du
ring
whi
ch p
assi
vati
on o
f th
e m
etal
tak
es p
lace
17-1
8 . X
-ray
dif
frac
tion
ana
lysi
s sh
owed
tha
t m
agne
tite
was
for
med
at
any
tem
pera
ture
fro
m 5
50 °
C t
o 65
0 °C
, bu
t fo
r te
mpe
ratu
res
grea
ter
than
570
°C
wus
tite
was
fou
nd t
o be
for
min
g be
neat
h th
e m
agne
tite
la
yer.
Its
for
mat
ion,
it
was
sug
gest
ed,
coul
d be
int
erpr
eted
as
a re
acti
on b
etw
een
oxyg
en a
nd
Fe
at t
he r
eact
ion
inte
rfac
e in
tw
o w
ays:
1.
Oxy
gen
perm
eate
d th
roug
h th
e ox
ide
laye
r to
rea
ct w
ith
the
iron
, or
2.
An
inte
rnal
rea
ctio
n be
twee
n F
e 3O
4 an
d F
e(F
e 3O
4+F
e F
eO)
due
to d
esta
bili
sati
on
of t
he F
e 3O
4 at
hig
h te
mpe
ratu
res.
N
o pr
efer
ence
was
est
abli
shed
. A
fter
non
-iso
ther
mal
tre
atm
ent,
whi
ch c
onsi
sted
of
a w
eek
long
exp
osur
e at
550
°C
fol
low
ed b
y a
peri
od o
f be
twee
n 8
to 2
4 ho
urs
at 7
00 °
C,
the
scal
e th
at f
orm
ed w
as f
ound
to
be v
ery
irre
gula
r du
e to
cra
ckin
g. T
he a
naly
sis
of t
he d
ata
indi
cate
d th
at
a pa
ssiv
atin
g ox
ide
was
fo
rmed
in
th
e fi
rst
(non
-iso
ther
mal
tr
eatm
ent)
cy
cle,
as
su
bseq
uent
dev
iati
ons
in t
he t
empe
ratu
re h
ad n
o ef
fect
on
the
oxid
atio
n ki
neti
cs.
In
term
s of
th
e ph
ases
pre
sent
in
the
oxid
e, t
hese
are
pre
sent
ed i
n T
able
IV
.
Tab
le I
V O
xid
e p
rod
uct
s p
rese
nt
in t
he
oxid
e sc
ale
s fo
rmed
aft
er n
on
-iso
ther
ma
l oxid
ati
on
tre
atm
ents
(aft
er R
ef. 1
6)
Tim
e sp
ent
at
550 °
C +
700 °
C
Slo
w C
oo
lin
g
Ra
pid
Co
oli
ng
7 da
ys +
4 h
ours
M
/M+
(W)
M/M
+(W
) 7
days
+ 8
hou
rs
/ M
/M+
W
7 da
ys +
24
hour
s M
/M+
W
M+
W/W
+M
7
days
+ 4
hou
rs +
7 d
ays
550
°C
M+
H/M
/
M –
mag
neti
te, H
– h
aem
atit
e, W
– w
usti
te.
Fig
ure
6 I
ron
-Oxy
gen
ph
ase
Dia
gra
m
NP
L R
epor
t M
AT
C(A
)90
Pag
e 9
of 3
9
In t
he c
ase
of t
he n
on-i
soth
erm
al t
reat
men
ts t
he r
elat
ive
amou
nts
of t
hese
con
stit
uent
s, a
s pr
esen
ted
in T
able
IV
, se
emed
to
be d
epen
dent
on
the
cool
ing
rate
and
the
tem
pera
ture
of
the
trea
tmen
t.
It s
houl
d be
not
ed t
hat
the
type
of
oxid
es f
orm
ed w
ithi
n th
is w
ork
wer
e in
ag
reem
ent
wit
h th
at w
hich
wou
ld b
e ex
pect
ed f
rom
the
iro
n-ox
ygen
pha
se d
iagr
am s
how
n in
F
igur
e 6.
It
is
gene
rall
y fo
und
that
whe
n ex
pose
d to
flo
win
g st
eam
the
se l
ow a
lloy
mat
eria
ls f
ollo
w a
pa
rabo
lic
grow
th r
ate
law
at
tem
pera
ture
s be
low
600
°C
, i.
e. c
onsi
sten
t w
ith
the
wor
k in
A
r/st
eam
. N
ava-
Paz
and
Kno
edle
r 19
com
pare
d th
e st
eam
oxi
dati
on b
ehav
iour
of
Gra
des
22
and
23.
The
y ob
serv
ed i
dent
ical
par
abol
ic g
row
th k
inet
ics
in b
oth
mat
eria
ls u
nder
flo
win
g st
eam
atm
osph
eres
at
600
°C,
the
rate
con
stan
t w
as q
uote
d as
bei
ng 5
.2 x
10-1
1 g2 c
m-2
s-1
. T
hey
foun
d th
at t
herm
al c
ycli
ng d
id n
ot a
ccel
erat
e th
e ox
idat
ion
rate
s; t
his
may
be
expl
aine
d by
the
obs
erva
tion
mad
e by
Arí
zteg
ui e
t a
l 16
in A
r/st
eam
whe
re a
pas
siva
ting
oxi
de f
orm
ed
in t
he f
irst
few
cyc
les.
In
con
tras
t, w
hen
test
ed i
n st
agna
nt s
team
the
y fo
und
that
the
mat
eria
ls f
ollo
wed
dif
fere
nt
grow
th k
inet
ics,
wit
h G
rade
23
foll
owin
g a
cubi
c ra
te l
aw (
tim
e ex
pone
nt =
0.3
3).
How
ever
th
ere
is s
ome
doub
t ab
out
the
reli
abil
ity
of t
esti
ng i
n st
agna
nt s
team
bec
ause
of
the
effe
ct o
f co
ncen
trat
ion
of i
mpu
riti
es e
tc.
It
is a
lso
appa
rent
fro
m t
his
revi
ew t
hat
the
resu
lts
obta
ined
fr
om d
iffe
rent
exp
erim
enta
l te
chni
ques
can
dif
fer
grea
tly,
thi
s w
ill
be i
llus
trat
ed a
t a
late
r po
int.
In
tes
t co
nduc
ted
usin
g pu
re w
ater
vap
our
Lep
ingl
e et
al
5 ex
pose
d si
x gr
ades
of
stee
ls a
t te
mpe
ratu
res
of 5
00,
550,
600
and
650
°C
for
537
6 h
(32
wee
ks).
T
he s
teel
s th
at t
hey
com
pare
d w
ere
T22
, T
23 a
nd t
he h
ighe
r C
r al
loys
of
T91
, T
92,
T12
2 an
d T
P34
7. T
he
corr
osio
n ra
tes
wer
e de
term
ined
by
mas
s ch
ange
mea
sure
men
ts, a
nd a
n ex
ampl
e of
the
res
ults
ob
tain
ed i
s sh
own
in F
igur
e 7.
Fig
ure
7 M
ass
ch
an
ge
of
T22
an
d T
23
ste
els
in w
ate
r vap
ou
r at
65
0 °
C (
aft
er R
ef. 5
)
NP
L R
epor
t M
AT
C(A
)90
Pag
e 10
of
39
The
rat
e ca
lcul
atio
ns p
erfo
rmed
wer
e in
agr
eem
ent
wit
h th
e ea
rlie
r w
ork
cond
ucte
d by
Nav
a-P
az a
nd K
noed
ler
19 w
ith
T22
and
T23
hav
ing
the
expo
nent
‘z’
val
ue a
s sh
own
in T
able
V.
Ta
ble
V C
alc
ula
ted
va
lues
of
the
‘z’
exp
on
ent
of
the
rela
tio
nsh
ip
zkt
m (
aft
er R
ef. 5
)
‘z’
exp
on
ent
at…
S
teel
500 °
C
550 °
C
600 °
C
650 °
C
T22
0.
46
0.49
0.
62
0.83
T
23
0.41
0.
41
0.71
0.
71
Thi
s su
gges
ts t
hat
at t
empe
ratu
res
belo
w 6
00 °
C,
T22
and
T23
obe
y a
para
boli
c la
w,
whi
ch
indi
cate
s th
at a
t th
ese
tem
pera
ture
s th
e m
ater
ials
are
sel
f-pr
otec
ting
. H
owev
er a
t hi
gh
tem
pera
ture
s th
e sc
ale
beco
mes
non
-pro
tect
ive
and
the
kine
tics
app
roac
h li
near
beh
avio
ur.
Alt
houg
h in
tere
stin
g th
is m
ater
ial
clas
s is
rar
ely
used
at
such
ele
vate
d te
mpe
ratu
res.
A
ltho
ugh
man
y of
the
rep
orte
d re
lati
onsh
ips
clai
m t
o be
fol
low
ing
para
boli
c ra
te l
aws,
oth
ers
rate
law
s ha
ve b
een
cite
d i.
e. l
ogar
ithm
ic,
com
bine
d fu
ncti
ons
etc.
In
a r
epor
t by
Bue
no a
nd
Mar
ino
20 d
ata
rela
ting
to
stea
m o
xida
tion
fro
m t
hree
dif
fere
nt s
ourc
es w
ere
com
pare
d w
ith
thei
r ow
n ‘d
ry’
oxid
atio
n da
ta.
Fig
ure
8 sh
ows
thre
e gr
aphs
com
pari
ng t
he f
our
sets
of
data
. In
eac
h pl
ot t
he ‘
dry’
oxi
dati
on d
ata
of B
ueno
and
Mar
ino
20 h
as b
een
com
pare
d to
dif
fere
nt
oxid
atio
n ra
te l
aws
sugg
este
d by
oth
er a
utho
rs 21
-22 ,
nam
ely
para
boli
c (p
lot
a) 21
, lo
gari
thm
ic
(plo
t b)
22
an
d as
a
com
bine
d fu
ncti
on
(plo
t c)
22
.
It
is
appa
rent
th
at
ther
e is
m
uch
disa
gree
men
t be
twee
n th
em;
and
that
the
pre
senc
e of
ste
am g
reat
ly a
ffec
ts t
he o
bser
ved
reac
tion
kin
etic
s. I
nter
esti
ngly
, th
e da
ta i
ndic
ate
that
the
oxi
dati
on r
ate
chan
ges
arou
nd 7
00
°C,
such
tha
t at
600
°C
kp
dry
> k
p st
eam
, w
hils
t at
700
°C
kp
dry
kp
stea
m a
nd a
t 80
0 °C
k p
dry
< k
p st
eam
. D
ata
in t
he l
iter
atur
e ar
e ge
nera
ted
usin
g th
ree
mai
n ex
peri
men
tal
met
hods
to
prod
uce
high
te
mpe
ratu
re s
team
env
iron
men
ts, s
tati
c st
eam
, pur
e fl
owin
g st
eam
and
a m
ixtu
re o
f st
eam
and
a
carr
ier
gas.
T
he o
xide
sca
les
form
ed a
nd t
he o
xida
tion
rat
e ar
e de
pend
ant
on w
hich
met
hod
is u
sed
and
the
tem
pera
ture
of
the
test
. T
o il
lust
rate
thi
s co
nsid
er F
igur
e 9,
whi
ch s
how
s th
e ox
idat
ion
rate
at
600°
C f
or T
22 a
nd T
23 i
n ai
r 20
, pur
e w
ater
vap
our
5 and
a m
ixtu
re o
f st
eam
an
d ar
gon
16.
It i
s cl
ear
from
Fig
ure
9 th
at:
S
team
has
a d
elet
erio
us e
ffec
t on
the
oxi
dati
on
T22
app
ears
to
oxid
ise
fast
er i
n pu
re s
team
tha
n in
a m
ixtu
re o
f st
eam
and
arg
on
The
kin
etic
s ar
e pa
rabo
lic
indi
cati
ng t
hat
the
pass
ivat
ing
scal
e is
not
spa
llin
g in
all
ca
ses
The
dif
ficu
lty
com
es i
n de
term
inin
g w
hich
exp
osur
e m
etho
d be
st r
epli
cate
s th
e in
-ser
vice
co
ndit
ions
, in
ter
ms
of b
oth
the
oxid
atio
n ra
te a
nd t
he m
orph
olog
y of
the
res
ulta
nt o
xide
sc
ale.
F
rom
the
lit
erat
ure
exam
ined
the
re i
s no
con
sens
us o
n th
ese
poin
ts a
nd a
lso
litt
le
men
tion
of
the
pote
ntia
l ef
fect
s of
ste
am c
hem
istr
y.
NP
L R
epor
t M
AT
C(A
)90
Pag
e 11
of
39
(a)
(c)
(b)
(a)
(c)
(b)
Fig
ure
8 C
om
pa
riso
n o
f d
ata
ob
tain
ed f
rom
fo
ur
sep
ara
te w
ork
s, i
llu
stra
tin
g h
ow
dif
fere
nt
rate
la
ws
can
be
use
d.
Th
e sy
mb
ols
sh
ow
‘d
ry’
oxid
ati
on
data
com
pare
d r
ate
law
s u
nd
er s
tea
m o
xid
ati
on
co
nd
itio
ns.
Plo
t (a
)
sho
ws
a p
ara
bo
lic
rate
, (b
) lo
ga
rth
imic
an
d (
c) i
s a
com
bin
ed f
un
ctio
n.
All
data
rel
ate
s to
2 ¼
Cr-
1M
o s
teel
(Aft
er R
ef. 20)
Fig
ure
9 C
om
pa
riso
n o
f o
xid
ati
on
ra
tes
at
600°C
usi
ng d
iffe
ren
t ex
posu
res
0
20
40
60
80
100
120
140
160
180
200
01000
2000
3000
4000
5000
6000
Tim
e (
h)
Air
oxid
ation o
f T
22
T22 in p
ure
wate
r vapour
T23 in p
ure
wate
r vapour
T22 in s
team
and a
rgon
NP
L R
epor
t M
AT
C(A
)90
Pag
e 12
of
39
Fro
m t
he a
vail
able
lit
erat
ure
seve
ral
mai
n po
ints
can
be
draw
n.
The
gro
wth
kin
etic
s ar
e af
fect
ed b
y se
vera
l fa
ctor
s; (
1) t
he f
low
rat
e of
the
ste
am a
tmos
pher
e, (
2) t
empe
ratu
re,
they
ra
nge
from
sub
par
abol
ic a
t lo
w t
empe
ratu
re (
500
°C)
to a
ppro
achi
ng l
inea
r at
650
°C
, (
3)
com
posi
tion
of
the
test
env
iron
men
t, t
he p
rese
nce
of w
ater
vap
our
in t
he t
est
atm
osph
ere
may
in
crea
se o
r de
crea
se c
orro
sion
rat
e, d
epen
ding
on
test
tem
pera
ture
.
4
9-1
2%
Cr
Ma
rten
siti
c S
teel
s
The
9-l
2% C
r st
eels
are
use
d in
bot
h bo
iler
s an
d in
ste
am t
urbi
nes
whe
re t
he a
lloy
s us
ed a
re
expo
sed
to h
igh
pres
sure
ste
am e
nvir
onm
ents
at
tem
pera
ture
s up
to
620
°C a
nd p
ress
ures
in
exce
ss o
f 30
0 ba
r.
In b
oil
ers
tha
t u
se f
oss
il f
uel
the
se s
teel
s ar
e us
ed f
or t
ubin
g in
sup
erhe
ater
s an
d re
heat
ers,
op
erat
ing
wit
h m
etal
tem
pera
ture
s up
to
abou
t 62
0 °C.
In
bo
iler
s fo
r n
ucl
ear
op
era
tio
n t
he s
teel
s ar
e ag
ain
used
for
tub
ing
in s
uper
heat
ers.
H
owev
er, i
n th
is c
ase
the
tem
pera
ture
s ar
e lo
wer
, typ
ical
ly 5
20 °
C.
In s
team
tu
rbin
es, a
lloy
s of
thi
s ty
pe a
re u
sed
for
roto
rs a
nd b
ladi
ng b
ut a
lso
in c
ast
form
for
st
eam
che
sts
and
valv
e bo
dies
. T
he
mor
phol
ogy
of
the
scal
es
form
ed
by
this
cla
ss o
f al
loy
is
ofte
n fo
und
to
cont
ain
mac
rosc
opic
def
ects
suc
h as
por
es,
crac
ks e
tc 5 .
Fur
ther
exa
min
atio
n of
the
oxi
de s
cale
s co
nduc
ted
by L
epin
gle
5 usi
ng X
RD
, S
EM
and
ED
X a
naly
sis
is r
epor
ted
to h
ave
show
n th
at
the
corr
osio
n pr
oduc
ts o
n T
91,
T92
and
T12
2 st
eels
hav
e an
Fe-
rich
out
er l
ayer
wit
h an
inn
er
laye
r th
at c
onsi
sts
of C
r, M
o, F
e ox
ides
. F
urth
erm
ore
in T
91 a
nd T
92 s
teel
s th
is i
nner
lay
er i
s in
its
elf
spli
t in
to t
wo
laye
rs, t
he o
ne c
lose
to t
he m
etal
was
fou
nd t
o be
oxy
gen-
depl
eted
5 . A
s w
ith
the
low
all
oy f
erri
tic
stee
ls t
he o
xida
tion
kin
etic
s of
mar
tens
itic
ste
els
have
bee
n sh
own
to
foll
ow
para
boli
c ra
te
cons
tant
s.
M
ongo
mer
y an
d K
arls
son
12 co
mpa
red
the
para
boli
c ra
te c
onst
ants
of
5 co
mm
erci
al m
arte
nsit
ic s
teel
s vi
z 9C
r1M
o, T
91,
X20
, T
92 a
nd
HC
M12
ove
r a
rang
e of
tem
pera
ture
s an
d pr
essu
res.
Typ
ical
com
posi
tion
s of
the
5 a
lloy
s ar
e gi
ven
in T
able
VI.
T
he d
ata
are
show
n in
det
ail
in F
igur
e 10
and
sum
mar
ised
in
Fig
ure
11.
The
app
aren
t sp
read
in
the
resu
lts
wit
hin
part
icul
ar a
lloy
sub
sets
was
att
ribu
ted
to f
acto
rs t
hat
may
not
hav
e be
en r
epor
ted,
suc
h as
sur
face
pre
para
tion
etc
. T
he e
xact
con
diti
ons
of t
he
stea
m e
xpos
ure
wer
e no
t gi
ven
in t
he p
aper
.
Dat
a w
ere
also
pre
sent
ed f
rom
tes
ts t
hat
wer
e ca
rrie
d ou
t at
dif
fere
nt s
team
pre
ssur
es.
No
sign
ific
ant
infl
uenc
e of
ste
am p
ress
ure
was
obs
erve
d al
thou
gh t
he a
utho
rs c
omm
ente
d th
at i
n so
me
case
s a
slig
ht i
ncre
ase
in p
arab
olic
rat
e co
nsta
nt i
s ob
serv
ed w
ith
incr
ease
d st
eam
pr
essu
re.
NP
L R
epor
t M
AT
C(A
)90
Pag
e 13
of
39
Ta
ble
VI
Co
mp
osi
tio
n (
wt%
) o
f 5
co
mm
erci
al
ma
rten
siti
c st
eels
C
M
n
Si
Cr
Mo
V
N
W
B
Ni
9Cr1
Mo
0.12
0.
45
0.6
9 1.
0
T91
0.
1 0.
45
0.4
9 1.
0 0.
2 0.
049
0.8
T92
0.
07
0.45
0.
06
9 0.
5 0.
2 0.
06
1.8
0.00
4
HC
M12
0.
1 0.
55
0.3
12
1.0
0.25
0.
03
1.0
X20
0.
20
1.0
0.5
12
1.0
0.3
0.
6
(a)
(b)
(c)
(d)
(a)
(b)
(c)
(d)
(e)
(f)
(e)
(f)
Fig
ure
10
Arr
hen
ius
plo
ts o
f st
eam
ox
ida
tio
n c
on
sta
nts
fo
r (a
) 10C
rMo
910
(T
22),
(b
) X
10C
rMoV
Nb
91
(T
91
), (
c)
X20C
rMo1
21
, (d
) H
CM
12
, (e
) N
F616
an
d (
f) c
om
pa
riso
n o
f a
ll t
he
pre
vio
us
ma
teri
als
(aft
er R
ef. 1
2)
NP
L R
epor
t M
AT
C(A
)90
Pag
e 14
of
39
Com
pari
son
of t
he r
elat
ive
oxid
atio
n ra
te o
f th
e st
eels
con
tain
ing
9%C
r sh
ows
that
9C
r1M
o is
su
bsta
ntia
lly
bett
er t
han
T91
and
T92
, w
ith
the
impr
ovem
ent
incr
easi
ng w
ith
incr
easi
ng
tem
pera
ture
. T
his
obse
rvat
ion
impl
ies
that
one
or
mor
e of
the
add
itio
nal
allo
ying
ele
men
ts i
n T
91 a
nd T
92 i
.e. V
, W o
r N
i, i
s de
trim
enta
l to
ste
am o
xida
tion
res
ista
nce.
A
be
et
al
23
stud
ied
the
infl
uenc
e of
m
inor
al
loyi
ng
addi
tion
s on
th
e st
eam
ox
idat
ion
beha
viou
r of
a 9
%C
r st
eel
at 6
00 a
nd 6
50 °
C.
Si
addi
tion
s im
prov
e th
e st
eam
oxi
dati
on
resi
stan
ce b
ut h
ave
the
dele
teri
ous
effe
ct o
f en
cour
agin
g ca
rbid
e ag
glom
erat
ion.
The
add
itio
n of
tra
ce a
mou
nts
of T
i or
Y(0
.05%
) fu
rthe
r im
prov
e th
e st
eam
oxi
dati
on r
esis
tanc
e of
all
oys
cont
aini
ng 0
.5%
Si
(Fig
ure
12)
23.
Re
cip
rica
l T
em
pe
ratu
re,
K-1
0.0
010
0.0
011
0.0
012
0.0
013
log kp, m2 h
-1
-3-2-101
T92
T91
9C
r1M
o
HC
M12
X20
Fig
ure
11 P
ara
boli
c ra
te c
on
stan
ts f
or
sever
al
stee
l all
oys
Fig
ure
12
Mass
ch
an
ge
of
the
stee
ls d
uri
ng
ox
idati
on
at
600
an
d 6
50
°C
(a
fter
Ref
. 2
3)
MASS CHANGE (mg.cm-2
) MASS CHANGE (mg.cm-2
)
NP
L R
epor
t M
AT
C(A
)90
Pag
e 15
of
39
The
ben
efic
ial
effe
ct o
f ad
diti
ons
of s
ilic
on t
o th
e al
loy
com
posi
tion
has
als
o be
en r
epor
ted
by H
urst
and
Cow
en 24
. T
o fu
rthe
r in
vest
igat
e th
is G
ries
s an
d M
axw
ell
7 exp
osed
a s
elec
tion
of
all
oys
cont
aini
ng a
ran
ge o
f si
lico
n co
ncen
trat
ions
to
supe
rhea
ted
stea
m a
t te
mpe
ratu
res
of
482
°C a
nd 5
38 °
C.
The
res
ults
are
pre
sent
ed i
n T
able
VII
. A
ltho
ugh
the
expo
sure
tim
e w
as
shor
t, i
t is
int
eres
ting
to
note
tha
t th
e m
ass
gain
s w
ere
gene
rall
y lo
wer
for
hig
her
sili
con
cont
ents
, an
exam
ple
of t
his
is s
how
n in
Fig
ure
13 f
or 9
Cr-
1 M
o st
eel.
T
ab
le V
II A
ver
ag
e m
ass
ga
ins
of
du
pli
cate
Cr-
Mo
ste
el s
pec
imen
s in
su
per
hea
ted
ste
am
(A
fter
Ref
. 7
)
Aver
age
weig
ht
gain
(g/m
2)
Des
ign
ati
on
S
ilic
on
co
nte
nt
(wt%
)
Tem
per
atu
re
(°C
) 997 h
2556 h
5729 h
482
19.1
23
.3
36.4
0.
11
538
35.2
47
.8
75.1
48
2 18
.1
22.6
35
.4
5 C
r-1
Mo
0.
14
538
34.7
46
.4
73.1
48
2 18
.9
23.0
35
.4
0.14
53
8 34
.2
45.2
70
.0
482
17.7
21
.5
32.9
7
Cr-
1 M
o
0.17
53
8 33
.3
44.0
70
.1
482
19.0
24
.4
43.0
0.
01
538
45.6
68
.1
121.
1 48
2 18
.6
23.5
39
.3
0.02
53
8 40
.4
53.2
92
.1
482
17.9
23
.1
39.8
0.
04
538
41.8
61
.8
103.
3 48
2 15
.5
18.8
29
.3
9 C
r-1
Mo
0.36
53
8 25
.7
34.4
58
.4
Fig
ure
13
Aff
ect
of
incr
easi
ng
th
e S
i co
nte
nt
of
9 C
r-1
Mo
Ste
el,
sim
ila
r a
ffec
ts w
ere
exh
ibit
ed b
y
low
er C
r co
nte
nt
all
oy
s a
s sh
ow
n i
n T
ab
le V
I(A
fter
Ref
. 7
)
9 C
r-1 M
o
0
20
40
60
80
100
120
140
01000
2000
3000
4000
5000
6000
7000
Tim
e,
hours
Weight gain, g/m2
0.0
1 S
i
0.0
2 S
i
0.0
4 S
i
0.3
6 S
i
48
2 °
C
53
8 °
C
Mass gain (g.m-2 )
9 C
r-1 M
o
0
20
40
60
80
100
120
140
01000
2000
3000
4000
5000
6000
7000
Tim
e,
hours
Weight gain, g/m2
0.0
1 S
i
0.0
2 S
i
0.0
4 S
i
0.3
6 S
i
48
2 °
C
53
8 °
C
Mass gain (g.m-2 )
NP
L R
epor
t M
AT
C(A
)90
Pag
e 16
of
39
Igar
ashi
et
al
25 ha
ve s
how
n th
at P
d ad
diti
ons
to 9
Cr
3.3W
ste
els
impr
ove
cree
p re
sist
ance
at
over
650
°C
and
ste
am o
xida
tion
rat
es a
t up
to 7
50 °
C d
ecre
ased
by
fact
or o
f 10
. H
enry
et
al
26 ex
pose
d a
refe
renc
e st
eel
sam
ple
to d
ry a
ir,
and
esta
blis
hed
that
und
er t
hese
co
ndit
ions
the
oxi
dati
on f
ollo
wed
a p
ure
para
boli
c ra
te l
aw f
or d
urat
ions
of
over
400
hou
rs
(kp=
8.76
x10-1
3 g2
cm-4
s-1
).
In t
he p
rese
nce
of w
ater
vap
our
the
sam
e m
ater
ial
show
ed
brea
kaw
ay c
orro
sion
aft
er o
nly
8 ho
urs.
Bef
ore
the
brea
kaw
ay o
ccur
red
the
kine
tics
fol
low
ed
a pa
rabo
lic
law
(k
p =
2.42
x10-1
2 g2
cm-4
s-1
) an
d th
en
acce
lera
ted
to
a li
near
ra
te
afte
r br
eaka
way
. A
com
pari
son
was
the
n co
nduc
ted
to i
llus
trat
e th
e ef
fect
of
incr
easi
ng t
he C
r co
nten
t fr
om 1
2 to
18%
and
inc
reas
ing
Si
from
0 t
o 1%
. I
n co
njun
ctio
n w
ith
this
, a
stud
y on
th
e ef
fect
of
the
wat
er v
apou
r pa
rtia
l pr
essu
re w
as c
ondu
cted
, va
ryin
g th
e pr
essu
re f
rom
15
0 m
bar
to 1
0 m
bar.
The
res
ults
are
pre
sent
ed i
n T
able
VII
I an
d in
Fig
ure
14.
Ta
ble
VII
I T
ime
to b
rea
kaw
ay
at
90
0 °
C a
s a
fu
nct
ion
of
the
com
posi
tion
of
the
stee
l an
d t
he
wate
r
part
ial
pre
ssu
re (
aft
er R
ef.
26)
12%
Cr
15%
Cr
18%
Cr
10
mba
r 15
0 m
bar
10 m
bar
150
mba
r 10
mba
r 15
0 m
bar
0% S
i N
ot s
tudi
ed
t =
5-8
h t
= 2
-3h
Not
stu
died
0.
5% S
i t
= 1
h t
= 1
h t
= 1
5h
t =
9h
t >
25h
t
> 2
5h
1% S
i N
ot s
tudi
ed
t >
50h
t
> 5
0h
Not
stu
died
T
he r
esul
ts s
how
ed t
hat
incr
easi
ng t
he S
i co
nten
t fr
om 0
to
1% i
n a
Fe-
15C
r al
loy,
inc
reas
ed
tim
e to
bre
akaw
ay f
rom
2 h
ours
to
mor
e th
an 5
0 ho
urs.
D
ecre
asin
g th
e w
ater
vap
our
part
ial
pres
sure
fro
m 1
50 m
bar
to 1
0 m
bar
dela
yed
the
init
iati
on o
f br
eaka
way
. T
his
beha
viou
r is
co
nsis
tent
wit
h ob
serv
atio
ns p
revi
ousl
y re
port
ed.
Fig
ure
14 O
xid
ati
on
cu
rves
of
stain
less
ste
els
wit
h v
ari
ou
s (a
) ch
rom
ium
an
d (
b)
sili
con
(fo
r 1
5%
Cr)
con
ten
ts, oxid
ised
at
900
°C i
n A
r+15%
H2O
(a
fter
Ref
. 2
6)
NP
L R
epor
t M
AT
C(A
)90
Pag
e 17
of
39
The
aff
ect
of i
ncre
asin
g th
e C
r an
d S
i co
nten
t of
the
all
oys
on t
he r
esis
tanc
e to
oxi
dati
on h
as
alre
ady
been
sho
wn
to h
ave
a dr
amat
ic e
ffec
t (s
ee F
igur
e 13
).
Incr
easi
ng t
he S
i co
nten
t in
th
ese
allo
ys d
elay
s th
e on
set
of b
reak
away
by
prev
enti
ng t
he c
hrom
ium
dif
fusi
on.
Thi
s is
ac
hiev
ed b
y th
e fo
rmat
ion
of S
iO2
at t
he m
etal
/oxi
de i
nter
face
, ei
ther
as
an i
nter
nal
oxid
e or
as
a c
onti
nuou
s la
yer
26.
M
urat
a et
al
27 o
bser
ved
slow
er o
xida
tion
kin
etic
s in
all
oys
that
had
bee
n pr
oduc
ed w
ith
incr
ease
d su
lphu
r co
nten
ts.
M
etal
logr
aphi
c ex
amin
atio
n sh
owed
th
at
sulp
hur
was
no
t in
corp
orat
ed
into
th
e ox
ide
scal
e bu
t in
stea
d co
ncen
trat
ed
ahea
d of
th
e sc
ale/
subs
trat
e in
terf
ace.
T
his
obse
rvat
ion
wou
ld i
mpl
y th
at d
iffu
sion
of
sulp
hur
ahea
d of
the
int
erfa
ce m
ay
beco
me
a ra
te-l
imit
ing
step
in
the
oxid
atio
n pr
oces
s.
How
ever
it
is p
ossi
ble
that
the
hig
h su
lphu
r le
vels
may
inc
reas
e th
e ri
sk o
f sc
ale
spal
lati
on d
urin
g th
erm
al c
ycli
ng.
For
thi
s cl
ass
of m
ater
ials
it
wou
ld a
ppea
r th
at o
ne o
f th
e m
ajor
fac
tors
inf
luen
cing
the
re
sist
ance
to
stea
m o
xida
tion
is
the
type
of
allo
ying
add
itio
n. M
uch
of t
he l
iter
atur
e re
view
ed
has
focu
sed
on t
his
and
com
pare
d th
e re
lati
ve r
esis
tanc
e of
all
oys
cont
aini
ng d
iffe
ring
ad
diti
ons.
A
ddit
ions
of
Si,
Ti
and
Y h
ave
been
obs
erve
d to
im
prov
e th
e st
eam
oxi
dati
on
resi
stan
ce
whi
lst
smal
l ad
diti
ons
of
Ni
redu
ce
the
resi
stan
ce.
It
is
im
port
ant
whe
n co
nsid
erin
g al
loyi
ng a
ddit
ions
to
mai
ntai
n a
glob
al p
ersp
ecti
ve o
f th
e ba
lanc
e be
twee
n th
e m
echa
nica
l pr
oper
ties
and
the
cor
rosi
on r
esis
tanc
e of
the
all
oys,
for
exa
mpl
e in
crea
sing
the
N
i co
nten
t w
ill
decr
ease
the
cre
ep r
esis
tanc
e an
d in
crea
sing
the
Si
cont
ent
may
lea
d to
he
tero
gene
ous
mic
rost
ruct
ures
. 5
A
ust
enit
ic S
teel
s
Aus
teni
tic
stee
ls a
re m
ore
expe
nsiv
e th
an c
orre
spon
ding
fer
riti
c st
eels
and
hav
e gr
eate
r co
effi
cien
ts o
f th
erm
al e
xpan
sion
and
rel
ativ
ely
poor
the
rmal
con
duct
ivit
y.
Con
sequ
entl
y ap
plic
atio
ns f
or a
uste
niti
c st
eels
are
res
tric
ted
to t
he h
ighe
r te
mpe
ratu
re b
oile
r tu
bes
i.e.
su
perh
eate
rs a
nd r
ehea
ters
and
to
spec
ific
sit
uati
ons
whe
re s
ever
e co
rros
ion
cond
itio
ns o
ccur
, e.
g. i
n bl
ack
liqu
or u
nits
. A
uste
niti
c m
ater
ials
are
oft
en u
sed
as w
eld
over
lay
on f
erri
tic
mat
eria
ls t
o re
pair
cor
rode
d ar
eas
or t
o pr
ovid
e pr
otec
tion
in
area
s w
here
cor
rosi
on c
ould
be
a pr
oble
m.
K
ey r
equi
rem
ents
are
:
Low
cos
ts
Goo
d fa
bric
abil
ity
Res
ista
nce
to a
lkal
i sa
lt c
orro
sion
W
elda
bili
ty
The
ph
ilos
ophy
be
hind
th
e al
loy
deve
lopm
ent
was
to
in
crea
se
the
volu
me
frac
tion
of
st
reng
then
ing
prec
ipit
ates
by
repl
acin
g ch
rom
ium
car
bide
s w
ith
othe
r m
ore
stab
le c
arbi
des,
w
hile
at
the
sam
e ti
me
free
ing
chro
miu
m b
ack
to t
he m
atri
x to
giv
e im
prov
ed c
orro
sion
re
sist
ance
. T
he c
ompo
siti
on a
nd m
echa
nica
l pr
oper
ties
of
seve
ral
com
mon
all
oys
are
give
n in
Tab
le I
X.
NP
L R
epor
t M
AT
C(A
)90
Pag
e 18
of
39
Ta
ble
IX
Co
mp
osi
tio
n o
f A
ust
enit
ic S
teel
s
Co
mp
osi
tio
n, w
t%
Oth
er
All
oy
A
lter
nati
ve
nom
encl
atu
re
C
Mn
Max
P
max
S
max
S
i
max
C
r M
o
N
Nb
N
i
AIS
I 30
2
0.15
2
0.04
5 0.
03
1 18
9
AIS
I 30
4
0.08
2
0.04
5 0.
03
1 18
8
AIS
I 32
1
0.08
2
0.04
5 0.
03
1 17
11
0.15
Ti
AIS
I 34
7
0.08
2
0.04
5 0.
03
1 17
11
0.8
Nb+
Ta
AIS
I 31
6
0.08
2
0.04
5 0.
03
1 17
2.
5
12
AIS
I 30
9
0.2
2 0.
045
0.03
1
23
14
AIS
I 31
0
0.25
2
0.04
5 0.
03
1.5
24
19
AS
ME
T
P34
7HF
G
0.
08
1.6
0.6
18
0.8
10
Tem
palo
y A
-1
SU
S32
1J1H
TB
0.
12
1.6
0.6
18
0.1
10
0.08
Ti
Tem
palo
y A
-3
SU
S30
9J4H
TB
0.
05
1.5
0.4
22
0.
15
0.7
15
0.00
2 B
S
uper
304H
S
US
304J
1HT
B
0.1
0.8
0.2
18
0.
1 0.
4 9
3.0
Cu
HR
3C
SU
S31
0J1T
B
0.06
1.
2
0.
4 25
0.2
0.45
20
HR
6W
0.
10
2.0
0.03
0.
03
1.0
23
0.4
max
40
6.
0 W
, 0.2
max
T
i N
F70
9 S
US
310J
2TB
0.
15
1
0.
5 20
1.
5
0.2
25
0.1
Ti
Ess
hete
125
0
0.09
6
0.03
0.
003
0.6
15
1 0.
04
10
0.
004
B, 0
.02
Al,
0.
9 N
b, 0
.25
V,
0.14
Cu
Fig
ure
15
Arr
hen
ius
plo
ts o
f st
eam
ox
ida
tio
n
con
sta
nts
fo
r (a
) 1
714
Cu
Mo
, (b
) A
ISI3
47 (
coa
rsed
gra
ined
), (
c) A
ISI3
47 (
fin
e g
rain
ed),
(d
) co
mp
ari
son
of
all
th
e p
rev
iou
s m
ate
rials
. C
om
po
stio
n
pre
sen
ted
in
Ta
ble
X. (a
fter
Ref
. 1
2)
(a)
(b)
(c)
(d)
NP
L R
epor
t M
AT
C(A
)90
Pag
e 19
of
39
Aus
teni
tic
stee
ls a
re u
sed
in m
any
area
s, w
hich
are
sub
ject
ed t
o va
ryin
g te
mpe
ratu
res
and
tem
pera
ture
gra
dien
ts.
Giv
en t
hat
thes
e m
ater
ials
gen
eral
ly h
ave
low
the
rmal
con
duct
ivit
ies
and
high
coe
ffic
ient
s of
the
rmal
exp
ansi
on,
high
the
rmal
str
esse
s ca
n de
velo
p re
sult
ing
in
fati
gue
crac
king
28.
The
hig
h co
effi
cien
ts o
f ex
pans
ion
cont
ribu
te t
o ox
ide
scal
e sp
alla
tion
of
aust
enit
ic a
lloy
s.
Res
earc
h du
ring
the
las
t de
cade
has
gen
eral
ly f
ocus
sed
on d
evel
opin
g hi
gh
stre
ngth
fer
riti
c st
eels
tha
t ca
n be
use
d in
stea
d of
the
aus
teni
tic
stee
ls.
Thi
s ha
s le
ad t
o th
e de
velo
pmen
t of
cos
t ef
fect
ive
ferr
itic
ste
els
capa
ble
of o
pera
ting
in
cond
itio
ns u
p to
620
°C
, w
hils
t st
ill
exhi
biti
ng g
ood
wel
dabi
lity
and
fra
ctur
e to
ughn
ess.
How
ever
, the
re i
s st
ill
a pl
ace
for
thes
e au
sten
itic
mat
eria
ls t
hat
are
prim
aril
y us
ed i
n th
e fi
nish
ing
stag
es o
f S
H/R
H t
ubin
g,
whe
re o
xida
tion
res
ista
nce
and
cree
p re
sist
ance
bec
ome
mor
e im
port
ant.
A
rrhe
nius
plo
ts,
sim
ilar
to
thos
e pr
esen
ted
earl
ier
for
the
ferr
itic
ste
els,
are
pre
sent
ed i
n F
igur
e 15
. P
lot
(d)
clea
rly
show
s th
e ge
nera
l tr
end
for
low
er r
ate
cons
tant
s w
ith
incr
easi
ng
Cr
leve
ls i
n th
e al
loys
, as
pre
viou
sly
disc
usse
d. I
f th
e di
ffer
ent
allo
ys a
re c
ompa
red
it c
an b
e se
en t
hat
all
exhi
bit
para
boli
c be
havi
our
apar
t fr
om H
R3C
. M
ontg
omer
y 12
com
men
ts t
hat
it
is d
iffi
cult
to
com
pare
dat
a ge
nera
ted
over
wid
ely
diff
erin
g ti
me
peri
ods
owin
g to
the
ob
serv
ed f
act
that
tha
t pa
rabo
lic
rate
con
stan
ts a
re g
ener
ally
hig
her
for
shor
t te
rm t
ests
tha
n lo
ng t
erm
. T
his
is a
fur
ther
dif
ficu
lty
enco
unte
red
whe
n co
mpa
ring
dat
a fr
om l
iter
atur
e so
urce
s.
Oto
guro
et
al
29 c
ondu
cted
ste
am e
xpos
ure
test
s on
4 s
teel
s, s
how
n in
Tab
le X
. T
he
test
s w
ere
fair
ly s
hort
ter
m w
ith
expo
sure
s of
500
h,
at t
empe
ratu
res
of 7
00 a
nd 6
50 °
C,
and
stea
m p
ress
ures
of
0.98
, 19.
6 an
d 34
.3 M
Pa.
Oxi
dati
on w
as m
easu
red
by m
ass
chan
ge.
T
ab
le X
Ch
emic
al
com
posi
tio
ns
of
stee
ls u
sed
by O
togu
ro e
t al
29
Cal
cula
tion
s ba
sed
on t
he a
ssum
ptio
n of
for
mat
ion
of C
r 2O
3, F
e 3O
4 an
d F
eO w
ere
mad
e an
d th
e ex
peri
men
tal
data
com
pare
d to
pre
dict
ed v
alue
s.
It w
as r
epor
ted
29 t
hat
allo
ys C
and
D
fall
ver
y cl
ose
to t
he t
heor
etic
al l
ine,
whi
ch c
orre
spon
ded
to l
ight
spa
llin
g, A
and
B d
evia
te
far
from
the
m i
ndic
atin
g he
avie
r sp
alla
tion
, as
sho
wn
in F
igur
e 16
. T
his
figu
re s
how
s th
eore
tica
l pr
edic
tion
s be
twee
n m
ass
gain
for
m o
xida
tion
and
mas
s lo
ss f
rom
des
cali
ng.
O
togu
ro e
t a
l 29
not
ed t
hat
the
resi
stan
ce t
o st
eam
oxi
dati
on w
as i
nflu
ence
d by
fou
r fa
ctor
s;
stea
m p
ress
ure,
tem
pera
ture
, C
r co
nten
t an
d N
i co
nten
t.
Mon
togo
mer
y et
al
12 s
ugge
st t
hat
by i
ncre
asin
g th
e pr
essu
re y
ou c
an i
ncre
ase
the
oxid
atio
n ra
te b
y de
crea
sing
the
int
egri
ty o
f th
e sc
ale.
T
his
has
the
seco
ndar
y af
fect
of
incr
easi
ng t
he o
xida
tion
rat
e by
inc
reas
ing
the
tem
pera
ture
of
th
e un
derl
ying
m
etal
su
bstr
ate.
The
ef
fect
of
pr
essu
re
is
illu
stra
ted
in
Fig
ure
17.
Und
er h
igh
stea
m p
ress
ure,
voi
ds a
nd c
avit
ies
wer
e fo
und
to h
ave
form
ed i
n th
e ou
ter
scal
e la
yer.
It
is c
laim
ed t
hat
this
is
attr
ibut
ed t
o th
e lo
cal
cess
atio
n of
the
sca
le g
row
th,
the
diff
eren
ce i
n th
e di
ffus
ion
rate
s of
the
met
alli
c io
ns i
n th
e ou
ter
and
inne
r sc
ale,
and
/or
a w
eake
ning
of
the
oxid
e gr
ain
boun
dari
es 29
.
Com
posi
tion
(w
t%)
All
oy
C
Ni
Cr
Mo
Ti
Nb
B
N
Cu
A
SU
S 3
47H
TB
0.
07
11.3
17.8
- -
0.72
- 0.
01
- B
17
-14C
uMo
0.11
14
.515
.92.
500.
240.
43-
0.01
3.
1 C
20
-Cr-
25N
i typ
e 0.
07
25.2
20.1
1.56
0.06
0.27
0.00
4 0.
18
- D
22
Cr-
35N
i ty
pe
0.08
33
.722
.11.
460.
120.
190.
005
0.03
-
NP
L R
epor
t M
AT
C(A
)90
Pag
e 20
of
39
Fig
ure
16
Wei
gh
t lo
ss a
nd
ga
in f
or
the
stee
ls t
este
d b
y O
togu
ro e
t a
l (a
fter
Ref
. 2
9).
Ste
el c
om
po
siti
on
s a
re s
ho
wn
in
Tab
le X
.
Fig
ure
17 R
elati
on
ship
bet
wee
n s
tea
m p
ress
ure
an
d m
ax
imu
m s
cale
th
ick
nes
s o
f st
eels
A,
B, C
an
d
D f
rom
wo
rk c
on
du
cted
by
Oto
gu
ro e
t al
29.
Ste
el c
om
po
siti
on
s a
re s
ho
wn
in
Ta
ble
X.
Mass gain (mg.cm-2 )
Mas
s lo
ss (
mg.
cm-2
)
Mass gain (mg.cm-2 )
Mas
s lo
ss (
mg.
cm-2
)
NP
L R
epor
t M
AT
C(A
)90
Pag
e 21
of
39
The
gas
vel
ocit
y ha
s be
en s
how
n to
str
ongl
y af
fect
the
oxi
dati
on o
f au
sten
itic
and
fer
riti
c ch
rom
ium
st
eels
.
In
wor
k co
nduc
ted
by
Ast
eman
et
a
l 30
it
w
as
conc
lude
d th
at
the
vapo
riza
tion
of
chro
miu
m f
rom
the
oxi
de i
n th
e fo
rm o
f ch
rom
ium
(V
I) o
xyhy
drox
ide
incr
ease
d th
e ox
idat
ion
rate
of
X20
, 30
4L a
nd 3
10 s
teel
s in
O2/
H2O
env
iron
men
ts.
The
y fo
und
that
at
low
gas
vel
ocit
ies
the
X20
and
310
sho
wed
com
plet
ely
prot
ecti
ve b
ehav
iour
. In
co
ntra
st t
he 3
04L
mat
eria
l di
d no
t fo
rm a
com
plet
ely
prot
ecti
ve o
xide
at
low
gas
vel
ocit
ies.
F
or h
ighe
r ga
s ve
loci
ties
(>
2.5
cm/s
), X
20 e
xhib
ited
bre
akaw
ay c
orro
sion
whi
le t
he o
xide
on
the
304L
and
310
was
obs
erve
d to
fai
l lo
call
y.
The
eff
ect
of e
vapo
rati
on i
s sc
hem
atic
ally
il
lust
rate
d in
Fig
ure
18.
Whi
lst
it i
s ge
nera
lly
acce
pted
tha
t st
eels
con
tain
ing
high
lev
els
of C
r ha
ve b
ette
r co
rros
ion
resi
stan
ce,
it w
as o
bser
ved
by O
togu
ro e
t a
l 29
tha
t th
e w
eigh
t lo
ss i
n al
loy
B i
s le
ss t
han
that
of
all
oy A
in
spit
e of
low
er C
r co
nten
t, a
s sh
own
in F
igur
e 19
. T
he a
utho
rs s
ugge
st t
hat
this
im
prov
emen
t in
ste
am o
xida
tion
is
caus
ed b
y th
e hi
gher
Ni
cont
ent.
T
he b
enef
it o
f N
i ad
diti
ons
was
als
o re
port
ed b
y C
roll
and
Wal
lwor
k 31
who
dem
onst
rate
d th
e be
nefi
t on
the
ox
idat
ion
resi
stan
ce i
n F
e-C
r-N
i al
loys
. C
apla
n an
d C
ohen
32 a
lso
show
ed t
hat
Ni
incr
ease
d ox
idat
ion
resi
stan
ce o
f st
ainl
ess
stee
ls i
n w
et a
ir.
It
is s
ugge
sted
tha
t th
is i
s du
e to
the
fo
rmat
ion
of a
Ni
enri
ched
lay
er.
As
wit
h m
arte
nsit
ic a
lloy
s it
has
als
o be
en d
emon
stra
ted
that
Si
play
s an
im
port
ant
role
in
enha
ncin
g th
e ox
idat
ion
resi
stan
ce o
f au
sten
itic
ste
els
by
form
ing
an i
nner
lay
er o
f si
lica
bet
wee
n th
e ox
ide
scal
e an
d th
e al
loys
by
prom
otin
g th
e ra
pid
form
atio
n of
Cr 2
O3.
T
his
laye
r of
sil
ica,
whi
ch g
row
s m
uch
mor
e sl
owly
tha
n ch
rom
ia,
acts
as
a d
iffu
sion
bar
rier
thu
s co
ntro
llin
g th
e tr
ansp
ort
of C
r io
ns 33
. C
hrom
ium
con
sum
ptio
n de
crea
ses
as a
res
ult
and
the
depl
eted
zon
e fo
rms
mor
e sl
owly
. S
ilic
a, i
t is
cla
imed
, al
so
decr
ease
s th
e ac
tivi
ty o
f F
e at
the
int
erfa
ce 33
.
Fig
ure
18
Sch
ema
tic
illu
stra
tio
n o
f th
e ox
idati
on
of
au
sten
itic
an
d f
erri
tic
chro
miu
m s
teel
s in
O2
/H2
O
env
iron
men
ts.
Th
e il
lust
rati
on
re p
rese
nts
th
e si
tuati
on
aft
er 1
68 h
ou
rs a
s re
po
rted
by
Ref
. 3
0
30-1
00nm
Cr-
rich
(C
r, F
e)2O
3
CrO
2(O
H) 2
(g)
CrO
2(O
H) 2
(g)
X20
X20
304/
310
304/
310
Fe 2
O3
Fe-
rich
(C
r, F
e)2O
3
Fe-
rich
(C
r, F
e)2O
3
304/
310
Fe 2
O3
or F
e-ri
ch (
Cr,
Fe)
2O3
Oxi
dati
on i
n dr
y O
2
O2/
H2O
Low
eva
pora
tion
rat
eP
rote
ctiv
e ox
ide
O2/
H2O
Med
ium
eva
pora
tion
rat
eP
artl
y pr
otec
tive
oxi
de
O2/
H2O
Hig
h ev
apor
atio
n ra
teN
on-p
rote
ctiv
e ox
ide
30-1
00nm
Cr-
rich
(C
r, F
e)2O
3
CrO
2(O
H) 2
(g)
CrO
2(O
H) 2
(g)
X20
X20
304/
310
304/
310
Fe 2
O3
Fe-
rich
(C
r, F
e)2O
3
Fe-
rich
(C
r, F
e)2O
3
304/
310
Fe 2
O3
or F
e-ri
ch (
Cr,
Fe)
2O3
Oxi
dati
on i
n dr
y O
2
O2/
H2O
Low
eva
pora
tion
rat
eP
rote
ctiv
e ox
ide
O2/
H2O
Med
ium
eva
pora
tion
rat
eP
artl
y pr
otec
tive
oxi
de
O2/
H2O
Hig
h ev
apor
atio
n ra
teN
on-p
rote
ctiv
e ox
ide
30-1
00 n
m30
-100
nmC
r-ri
ch (
Cr,
Fe)
2O3
CrO
2(O
H) 2
(g)
CrO
2(O
H) 2
(g)
X20
X20
304/
310
304/
310
Fe 2
O3
Fe-
rich
(C
r, F
e)2O
3
Fe-
rich
(C
r, F
e)2O
3
304/
310
Fe 2
O3
or F
e-ri
ch (
Cr,
Fe)
2O3
Oxi
dati
on i
n dr
y O
2
O2/
H2O
Low
eva
pora
tion
rat
eP
rote
ctiv
e ox
ide
O2/
H2O
Med
ium
eva
pora
tion
rat
eP
artl
y pr
otec
tive
oxi
de
O2/
H2O
Hig
h ev
apor
atio
n ra
teN
on-p
rote
ctiv
e ox
ide
30-1
00nm
Cr-
rich
(C
r, F
e)2O
3
CrO
2(O
H) 2
(g)
CrO
2(O
H) 2
(g)
X20
X20
304/
310
304/
310
Fe 2
O3
Fe-
rich
(C
r, F
e)2O
3
Fe-
rich
(C
r, F
e)2O
3
304/
310
Fe 2
O3
or F
e-ri
ch (
Cr,
Fe)
2O3
Oxi
dati
on i
n dr
y O
2
O2/
H2O
Low
eva
pora
tion
rat
eP
rote
ctiv
e ox
ide
O2/
H2O
Med
ium
eva
pora
tion
rat
eP
artl
y pr
otec
tive
oxi
de
O2/
H2O
Hig
h ev
apor
atio
n ra
teN
on-p
rote
ctiv
e ox
ide
30-1
00 n
m
NP
L R
epor
t M
AT
C(A
)90
Pag
e 22
of
39
The
re h
as b
een
litt
le i
nves
tiga
tive
wor
k in
to t
he c
ompa
rati
ve e
ffec
t of
the
gra
in s
izes
wit
hin
the
base
met
al a
nd t
he e
ffec
t th
is h
as o
n st
eam
oxi
dati
on.
Alt
houg
h it
has
bee
n re
port
ed b
y T
eran
ishi
35-3
6 tha
t th
ere
is a
mar
ked
impr
ovem
ent
in t
he c
orro
sion
res
ista
nce
of f
ine
grai
ned
(AS
TM
10)
, A
ISI
347,
com
pare
d to
a c
oars
e gr
aine
d (A
ST
M 3
) ve
rsio
n of
the
all
oy.
It
is
Fig
ure
19
Eff
ect
of
stea
m p
ress
ure
on
lo
ss i
n w
eigh
t fo
r st
eels
tes
ted
by O
togu
ro e
t al
29
Fig
ure
20
Eff
ects
of
Cr
con
ten
t a
nd
gra
in s
ize
of
au
sten
itic
sta
inle
ss s
teel
on
stea
m o
xid
ati
on
(aft
er R
ef. 3
4)
NP
L R
epor
t M
AT
C(A
)90
Pag
e 23
of
39
sugg
este
d th
at e
ven
wit
h a
low
Cr
cont
ent
allo
y, a
pro
tect
ive
chro
miu
m o
xide
lay
er c
an b
e ob
tain
ed t
hrou
gh a
fin
er g
rain
siz
e 29
. F
igur
e 20
sho
ws
som
e co
mpa
rati
ve d
ata
repo
rted
in
an
EP
RI
repo
rt 34
show
ing
the
affe
ct o
f th
e gr
ain
size
and
Cr
cont
ent
for
aust
enit
ic s
tain
less
ste
el
in s
team
at
650
°C f
or 1
000
h.
Oto
guro
29 al
so o
bser
ved
such
beh
avio
ur i
n hi
s st
udie
s.
Thi
s ef
fect
is
like
ly t
o be
due
to
fast
er d
iffu
sion
of
Cr
alon
g th
e gr
ain
boun
dari
es s
uch
that
loc
al
depl
etio
n be
neat
h th
e ox
ide
scal
e do
es n
ot o
ccur
.
The
exp
osur
e te
chni
que
can
have
a m
arke
d ef
fect
on
the
data
obt
aine
d, a
s de
mon
stra
ted
wit
h th
e lo
wer
Cr
cont
aini
ng a
lloy
s.
In w
ork
carr
ied
out
by G
ries
s an
d M
axw
ell
7 , as
dis
cuss
ed
prev
ious
ly,
sam
ples
of
allo
y 80
0, a
lloy
617
and
Typ
e 30
4 st
ainl
ess
stee
l w
ere
expo
sed
to
actu
al p
lant
ste
am.
The
com
posi
tion
s of
the
all
oys
are
give
n in
Tab
le X
I.
The
y cl
aim
tha
t in
th
e ca
se o
f th
e A
lloy
800
and
the
304
sta
inle
ss s
teel
ini
tial
kin
etic
s fo
llow
ed a
par
abol
ic
grow
th r
ate
unti
l ab
out
7000
hou
rs f
ollo
wed
by
a sh
ift
to m
ore
line
ar o
xida
tion
kin
etic
s, a
s pr
evio
usly
ex
hibi
ted
by
the
2¼C
r-1
Mo
spec
imen
s.
A
ltho
ugh
the
oxid
atio
n ki
neti
cs
exhi
bite
d th
e sa
me
patt
ern,
the
deg
ree
of o
xida
tion
was
muc
h lo
wer
, as
wou
ld b
e ex
pect
ed
beca
use
of t
he i
ncre
ased
Cr
cont
ent.
Fig
ure
21 s
how
s th
e w
eigh
t ga
in p
lots
for
All
oy 8
00 a
nd
the
304
stai
nles
s st
eel
sam
ples
.
Ta
ble
XI
Co
mp
osi
tio
n o
f te
st m
ate
ria
ls (
Aft
er R
ef. 7
)
Com
posi
tion
(w
t%)
All
oy
C
Cr
Ni
Mo
Fe
Mn
Si
Oth
er
All
oy 8
00
0.08
20
.78
33.9
0
43.4
6
0.
44 T
i, 0
.46
Al
All
oy 6
17
0.07
20
.30
57.3
58.
581.
01
0.05
0.16
11.7
2 C
o, 0
.76
Al
304
stai
nles
s st
eel
0.06
18
.04
8.90
Bal
. 1.
840.
55
Sur
face
pre
para
tion
is
a fu
rthe
r fa
ctor
tha
t w
ill
infl
uenc
e th
e ox
idat
ion
rate
of
a m
ater
ial.
In
th
e ca
se o
f th
e A
lloy
800
sam
ples
hal
f w
ere
solu
tion
ann
eale
d at
117
7 °C
for
30
min
utes
in
argo
n an
d ai
r co
oled
and
the
n pi
ckle
d in
HN
O3-
HF
, th
e ot
her
half
wer
e te
sted
as
grou
nd
wit
hout
bei
ng h
eat-
trea
ted.
It
is
imm
edia
tely
app
aren
t th
at t
he g
roun
d sa
mpl
e ox
idis
ed a
t a
very
low
rat
e.
Fro
m f
urth
er s
tudy
of
the
pick
led
sam
ples
it
was
not
ed t
hat
they
had
ap
pare
ntly
be
en
sens
itis
ed
duri
ng
the
cool
ing
proc
ess
and
subs
eque
ntly
co
rrod
ed
inte
rgra
nula
rly
duri
ng t
he p
ickl
ing
proc
ess.
T
he d
epth
of
the
grai
n bo
unda
ry p
enet
rati
on
prod
uced
by
pick
ling
was
abo
ut 2
00
m,
it i
s re
port
ed t
hat
this
dep
th d
id n
ot i
ncre
ase
as a
re
sult
of
stea
m e
xpos
ure.
It
is
clea
r th
at c
are
shou
ld b
e ta
ken
whe
n pe
rfor
min
g su
rfac
e tr
eatm
ents
as
it i
s es
tabl
ishe
d th
at g
roun
d su
rfac
es o
f al
loy
800
corr
ode
less
in
stea
m t
han
anne
aled
one
s, o
ther
all
oys
may
adh
ere
to t
his
obse
rvat
ion.
A
ll o
f th
e 30
4 st
ainl
ess
stee
l sa
mpl
es w
ere
anne
aled
and
pic
kled
, and
the
n gr
ound
. T
here
was
no
evi
denc
e of
the
sen
siti
sing
eff
ect
as s
een
wit
h al
loy
800.
T
he p
enet
rati
ons
and
corr
osio
n ra
tes
wer
e sm
all
whe
n co
mpa
red
wit
h th
e fe
rrit
ic s
teel
s th
at w
ere
also
tes
ted.
T
he g
row
th o
f ox
ides
sca
les
on C
r-M
o st
eels
and
the
aus
teni
tic
stai
nles
s al
loys
is
gene
rall
y co
nsid
ered
to
be
from
bo
th
outw
ard
mig
rati
on
of
iron
io
ns
to t
he
surf
ace,
w
here
th
ey
reac
t w
ith
wat
er
mol
ecul
es,
and
the
inw
ard
diff
usio
n of
oxy
gen
ions
to
the
met
al-o
xide
int
erfa
ce,
whe
re t
hey
reac
t w
ith
the
met
al 37
. N
o ex
plan
atio
n fo
r th
e ch
ange
fro
m p
arab
olic
to
a li
near
(F
igur
e 21
) ra
te w
as o
ffer
ed b
y th
e au
thor
s fo
r th
e pr
evio
us w
ork.
NP
L R
epor
t M
AT
C(A
)90
Pag
e 24
of
39
Fro
m t
he l
iter
atur
e tw
o m
ain
poin
ts a
re c
lear
reg
ardi
ng t
his
clas
s of
mat
eria
l, n
amel
y th
at t
he
oxid
atio
n ra
te i
ncre
ases
wit
h hi
gh p
ress
ure
atm
osph
eres
and
tha
t fi
ne g
rain
siz
es i
mpr
ove
the
oxid
atio
n re
sist
ance
by
supp
lyin
g C
r to
the
sur
face
.
6
Ni-
an
d C
o-b
ase
d a
llo
ys
Ni-
and
Co-
base
d al
loys
are
use
d fo
r “h
ot-e
nd”
part
s in
gas
tur
bine
s an
d al
thou
gh t
here
are
so
me
othe
r m
inor
app
lica
tion
s, i
t is
the
req
uire
men
ts d
efin
ed f
or g
as t
urbi
nes
that
dri
ve
deve
lopm
ents
. In
the
abs
ence
of
impr
oved
mat
eria
ls t
he o
nly
opti
on o
pen
to t
he d
esig
n en
gine
er f
aced
wit
h de
velo
ping
eng
ines
wit
h gr
eate
r pe
rfor
man
ce i
s to
des
ign
impr
oved
co
olin
g te
chno
logi
es.
The
key
pro
pert
y re
quir
emen
ts a
re i
ndic
ated
bel
ow.
Bla
des
and V
anes
:
Hig
h cr
eep
stre
ngth
at
tem
pera
ture
s up
to
1150
°C
G
ood
proc
essi
bili
ty i
n si
ngle
cry
stal
and
D.S
. fo
rms
to e
nsur
e hi
gh c
asti
ng y
ield
s to
re
duce
cos
ts
Thi
n-w
all
cast
ings
wit
h hi
gh s
tren
gth
Hig
h th
erm
o-m
echa
nica
l fa
tigu
e (T
MF
) re
sist
ance
A
dher
ent
oxid
e la
yer
for
good
oxi
dati
on r
esis
tanc
e R
esis
tanc
e to
hot
sal
t co
rros
ion
Fig
ure
21
Mass
ga
ins
for
all
oy 8
00
an
d 3
04
Sta
inle
ss S
teel
in
su
per
hea
ted
ste
am
(aft
er R
ef. 7
)
012345678
05000
10000
15000
20000
25000
30000
Tim
e (
h)
Allo
y 8
00 G
round 5
38°C
Allo
y 8
00 S
ensitiz
ed a
nd p
ickle
d 5
38°C
Allo
y 8
00 S
ensitiz
ed a
nd p
ickle
d 4
82°C
304 S
S 4
82°C
304 S
S 5
38°C
NP
L R
epor
t M
AT
C(A
)90
Pag
e 25
of
39
Dis
cs:
U
nifo
rm g
rain
str
uctu
re (
proc
essi
ng o
f la
rge
forg
ings
) F
ract
ure
toug
hnes
s an
d re
sist
ance
to
fati
gue
crac
k in
itia
tion
and
gro
wth
L
ow C
ycle
Fat
igue
res
ista
nce
Res
ista
nce
to S
AG
BO
C
om
bu
stors
:
In
crea
sed
tem
pera
ture
cap
abil
ity
Wel
dabi
lity
and
for
mab
ilit
y
Low
Cyc
le F
atig
ue r
esis
tanc
e G
ood
repa
irab
ilit
y C
are
shou
ld b
e ex
erci
sed
whe
n te
stin
g th
is c
lass
of
mat
eria
ls a
s th
e en
viro
nmen
tal
cond
itio
ns,
prim
aril
y th
e pr
esen
ce
of
oxyg
en
and/
or
moi
stur
e in
th
e te
st
envi
ronm
ents
, ha
ve
been
ob
serv
ed t
o ha
ve s
igni
fica
nt e
ffec
ts 38
.
Com
mon
ly c
oati
ngs
are
used
to
conf
er c
orro
sion
res
ista
nce.
N
onet
hele
ss c
orro
sion
res
ista
nt
allo
ys h
ave
been
dev
elop
ed w
here
gen
eral
ly a
hig
her
Cr/
Al
rati
o is
req
uire
d th
an a
lloy
s de
velo
ped
pure
ly
for
cree
p re
sist
ance
.
Mo
whi
ch
was
pr
esen
t as
a
soli
d so
luti
on
stre
ngth
enin
g el
emen
t ha
s po
or h
ot c
orro
sion
per
form
ance
and
thi
s is
nor
mal
ly r
epla
ced
by
refr
acto
ry e
lem
ent
such
as
W, T
a an
d N
b 39
. A
ltho
ugh
quit
e a
wid
ely
used
cla
ss o
f m
ater
ial,
ver
y li
ttle
inf
orm
atio
n is
ava
ilab
le i
n th
e op
en
lite
ratu
re r
egar
ding
the
ste
am o
xida
tion
beh
avio
ur.
Exp
osur
es i
n di
ffer
ent
form
s of
ste
am,
that
is
flow
ing
plan
t, s
tati
c et
c, h
ave
been
rep
orte
d in
wor
k pr
evio
usly
dis
cuss
ed i
n th
e ea
rlie
r se
ctio
ns.
Thu
s G
ries
s an
d M
axw
ell
7 exp
osed
sam
ples
of
All
oy 6
17 t
o pl
ant
stea
m.
Ver
y li
ttle
cor
rosi
on o
ccur
red
duri
ng t
he t
est,
alt
houg
h fo
r N
i-ba
sed
allo
ys t
he t
empe
ratu
re w
as l
ow
(482
and
538
°C
).
The
oxi
de l
ayer
for
med
on
the
sam
ples
was
so
thin
tha
t it
was
cla
imed
to
be u
ndet
ecta
ble
at a
mag
nifi
cati
on o
f 50
0x.
The
com
posi
tion
of
the
allo
y is
pre
sent
ed i
n T
able
XII
.
NP
L R
epor
t M
AT
C(A
)90
Pag
e 26
of
39
Tab
le X
II C
om
posi
tio
n o
f m
ate
rials
Co
mp
osi
tion
(w
t%)
All
oy
C
C
r N
i C
o
Mo
F
e M
n
Si
Oth
er
All
oy 6
17
0.07
20
.30
57.3
5 11
.72
8.58
1.01
0.05
0.16
0.76
Al
Inco
loy
800
0.04
20
.0
33.0
45
.20.
850.
400.
007
S, 0
.41
Cu
Inco
nel
600
0.04
16
.3
75.9
7.
240.
170.
290.
007
S
Inco
nel
625
0.03
22
.0
62.3
8.75
1.86
0.12
0.25
0.17
Al,
0.0
07 S
[(
Cb
+ T
a) 4
.24,
Ti]
0.2
3 In
cone
l X
750
0.04
15
.13
72.5
6.
870.
450.
250.
74 A
l, 0
.007
S
(Cb
+ T
a) 0
.98,
Ti
2.62
R
ene
41
0.07
19
.05
55.0
2 10
.95
9.83
0.3
0.
051.
52 A
l, 3
.21
Ti
In m
uch
olde
r w
ork
cond
ucte
d by
Rut
her
and
Gre
enbe
rg 40
a n
umbe
r of
all
oys
wer
e te
sted
at
650
°C i
n st
atic
aut
ocla
ves
for
shor
t du
rati
ons.
T
he r
esul
ts o
f th
ese
test
s ar
e pr
esen
ted
in
Fig
ure
22.
Res
ults
fro
m e
arli
er c
orro
sion
tes
ts o
n ty
pe 3
04 a
nd 4
06 s
teel
hav
e be
en i
nclu
ded
to e
stab
lish
ref
eren
ce l
evel
s.
Of
the
Ni-
base
d al
loys
tes
ted
Inco
nel
600
and
Inco
nel
X75
0 (I
ncon
el X
in
Fig
ure
22)
offe
red
the
wea
kest
cor
rosi
on r
esis
tanc
e. T
he t
hree
rem
aini
ng a
lloy
s al
l sh
owed
met
al l
osse
s le
ss t
han
type
406
(re
fere
nce
line
sho
wn
in F
igur
e 22
) fo
r ex
posu
res
up t
o 56
day
s (1
344
hour
s).
It h
as b
een
dem
onst
rate
d in
ear
lier
sec
tion
s th
at t
he s
urfa
ce p
repa
rati
on c
an i
nflu
ence
the
ox
idat
ion
kine
tics
in
stea
m e
xpos
ures
. T
his
clas
s of
all
oy h
as a
lso
been
obs
erve
d to
dis
play
th
is e
ffec
t.
Inco
loy
800
is r
epor
ted
to h
ave
exhi
bite
d a
stro
ng s
urfa
ce p
repa
rati
on e
ffec
t.
The
m
etal
los
s in
crea
sed
from
0.1
3 to
4.6
7 m
g.cm
-2 w
hen
the
surf
ace
was
ele
ctro
-pol
ishe
d as
op
pose
d to
bei
ng j
ust
wet
gro
und.
Ja
nsso
n et
al
41 h
ave
cond
ucte
d fu
rthe
r in
vest
igat
ions
co
ncer
ning
the
eff
ect
of s
urfa
ce p
repa
rati
on,
com
pari
ng g
roun
d su
rfac
es w
ith
pick
led
ones
. T
hey
foun
d th
at g
roun
d su
rfac
es e
xhib
ited
low
er m
ass
gain
tha
n pi
ckle
d on
es f
or a
ll t
he
allo
ys t
hey
test
ed u
p to
650
°C
. T
he b
enef
icia
l ef
fect
of
grin
ding
was
fou
nd t
o de
crea
se w
ith
incr
easi
ng t
empe
ratu
re u
p to
800
°C
, th
e re
tard
atio
n ca
used
by
grin
ding
bei
ng r
educ
ed t
o a
fact
or o
f 1-
3.
The
res
ults
for
an
allo
y w
ith
nom
inal
com
posi
tion
of
16%
Cr
and
75%
Ni
are
show
n in
Fig
ure
23.
NP
L R
epor
t M
AT
C(A
)90
Pag
e 27
of
39
F
igu
re 2
2 C
orr
osi
on
of
nic
kel
all
oys
in f
low
ing
ste
am
; 65
0 °
C, 42
kg
.cm
-2,
61 m
/s v
elo
city
, 30 p
pm
oxygen
(aft
er R
ef. 4
0)
Fig
ure
23
Mass
ga
in r
esu
lts
of
a N
i-b
ase
All
oy (
aft
er R
ef. 4
1)
Mass
gain
of
1675 i
n s
tea
m w
ith
low
oxy
gen
con
ten
t
Mass gain (mg.dm-2 )
Mass
gain
of
1675 i
n s
tea
m w
ith
low
oxy
gen
con
ten
t
Mass gain (mg.dm-2 )
NP
L R
epor
t M
AT
C(A
)90
Pag
e 28
of
39
The
im
prov
emen
t be
stow
ed b
y gr
indi
ng c
an b
e ex
plai
ned
in t
he f
ollo
win
g w
ay.
The
gri
ndin
g pr
oces
s, i
t is
sug
gest
ed, c
ause
s a
high
den
sity
of
disl
ocat
ions
or
sub-
grai
n bo
unda
ries
, the
se i
n tu
rn p
rovi
de c
hrom
ium
enh
ance
d di
ffus
ion
path
s, w
hich
lea
ds t
o a
high
er l
evel
of
chro
miu
m
in t
he m
etal
lay
er b
enea
th t
he o
xide
, th
us i
mpa
rtin
g gr
eate
r pr
otec
tion
to
the
base
met
al.
The
ab
senc
e of
thi
s re
tard
ing
effe
ct a
t th
e hi
gher
tem
pera
ture
s is
a c
onse
quen
ce o
f re
cove
ry a
nd
recr
ysta
llis
atio
n of
the
sur
face
str
uctu
re.
It
was
als
o ob
serv
ed t
hat
incr
easi
ng t
he o
xyge
n co
nten
t of
the
ste
am c
ause
d th
e re
tard
ing
effe
ct o
f gr
indi
ng t
o di
min
ish.
O
ne o
f th
e m
ain
diff
icul
ties
in
revi
ewin
g th
e st
eam
oxi
dati
on c
hara
cter
isti
cs o
f th
is c
lass
of
mat
eria
l ha
s be
en t
he l
ack
of i
nfor
mat
ion
open
ly a
vail
able
wit
h th
e li
tera
ture
, al
thou
gh s
ome
inte
rest
ing
poin
ts h
ave
been
hig
hlig
hted
abo
ve.
7
M
ech
an
ism
s o
f O
xid
ati
on
Un
der
En
vir
on
men
ts C
on
tain
ing
Wa
ter
Va
po
ur
It i
s w
ell
know
n th
at t
he o
xida
tion
beh
avio
ur o
f al
loys
in
envi
ronm
ents
tha
t co
ntai
n w
ater
va
pour
dif
fers
str
ongl
y fr
om t
hat
in ‘
dry’
atm
osph
eres
e.g
. ox
ygen
or
air.
H
owev
er t
here
is
stil
l no
t a
com
plet
e un
ders
tand
ing
of t
he m
echa
nism
s be
hind
the
se o
bser
vati
ons.
T
here
are
fiv
e m
ain
mec
hani
sms
com
mon
ly u
sed
to a
ccou
nt f
or t
he e
ffec
t of
wat
er v
apou
r on
ox
idat
ion
kine
tics
. T
hey
are
46:
D
isso
ciat
ion
mec
hani
sm
Oxi
dant
-gas
pen
etra
tion
mec
hani
sm
For
mat
ion
and
vola
tili
sati
on o
f F
e(O
H) 2
F
orm
atio
n an
d vo
lati
lisa
tion
of
CrO
2(O
H) 2
C
hang
es i
n th
e ox
ide
defe
ct s
truc
ture
via
pro
ton
diss
olut
ion
7.1
D
isso
cia
tion
Mec
ha
nis
m
The
dis
soci
atio
n m
echa
nism
, pro
pose
d by
Fuj
ii a
nd M
euss
ner
47-4
8 , is
illu
stra
ted
in F
igur
e 24
. M
etal
ion
s th
at a
re g
ener
ated
fro
m r
eact
ions
at
inte
rfac
es (
2) a
nd (
4),
mig
rate
to
the
oute
r in
terf
ace
of t
he o
xide
sca
le a
nd t
he a
tmos
pher
e (1
), w
here
wat
er v
apou
r is
ads
orbe
d.
The
su
bseq
uent
rea
ctio
n fo
rms
wus
tite
, de
fect
s in
the
oxi
de a
nd a
dsor
bed
hydr
ogen
. M
ost
of t
he
hydr
ogen
is
beli
eved
to
deso
rb, b
ut s
ome
wil
l di
ssol
ve i
n th
e ox
ide.
NP
L R
epor
t M
AT
C(A
)90
Pag
e 29
of
39
At
inte
rfac
e (1
) th
e re
acti
ons
are
prop
osed
to
be a
s fo
llow
s,
)(
)(
2
)(
2)
(2
)(
22
)(
2
)(
2)
(2
2
2'
'2
ox
ad
s
gad
s
ad
sva
cad
s
ad
sg
HH
HH
HF
eF
eOe
Fe
OH
OH
OH
whe
re F
e vac
in
dica
tes
a va
cant
iro
n io
n si
te a
nd
is
an
elec
tron
def
ect,
H* r
epre
sent
s hy
drog
en d
isso
lved
wit
hin
the
oxid
e.
The
iro
n ox
ide
at i
nter
face
(2)
is
beli
eved
to
diss
ocia
te a
nd p
rodu
ce a
n ox
ide
ion
as a
n ad
sorb
ed s
peci
es.
The
per
mea
ting
hyd
roge
n pe
rmit
s th
ese
adso
rbed
spe
cies
to
reac
t to
for
m
the
carr
ier
gas
for
oxyg
en t
rans
port
to
the
void
, as
foll
ows,
eO
HO
H
HH
HH
OF
eF
eF
eO
ga
ds
ad
s
ga
sa
ds
ad
so
x
vac
2
2
2
)(
2)
(2
)(
2
)(
2)
(2
)(
2)
(
22
Wus
tite
lay
ers
of t
he o
uter
sca
le a
re f
orm
ed i
n th
is r
esul
tant
atm
osph
ere
by t
he r
eact
ion
as
defi
ned
for
the
inte
rfac
es (
1) a
nd (
2).
In
this
way
rea
ctio
ns s
imil
ar t
o th
ose
foun
d at
(1)
als
o oc
cur
at i
nter
face
(3)
. T
he c
ompo
siti
on o
f th
e sp
inel
pha
se i
s be
liev
ed t
o be
alt
ered
, su
ch
that
,
eF
eC
rOF
eF
eOO
FeC
r2
24
24
24
2
Fig
ure
24 D
isso
ciati
on
mec
han
ism
pro
pose
d b
y F
uji
i an
d M
euss
ner
(aft
er R
ef. 46)
(1)
(2)
(3)
(4)
Sub
scal
e A
lloyFeO +
Spi
nel
+V
oid
FeO
H
Fe+
2
2e
Voi
d
Fe+
2
2e
H2(
g)
H2O
(g)
H2O
(g)
H2(
g)
PH
2O(1
)>
PH
2O(2
)>
PH
2O(3
)
(1)
(2)
(3)
(4)
Sub
scal
e A
lloyFeO +
Spi
nel
+V
oid
FeO
H
Fe+
2
2e
Voi
d
Fe+
2
2e
H2(
g)
H2O
(g)
H2O
(g)
H2(
g)
PH
2O(1
)>
PH
2O(2
)>
PH
2O(3
)
NP
L R
epor
t M
AT
C(A
)90
Pag
e 30
of
39
Thi
s m
echa
nism
for
the
for
mat
ion
of a
n in
ner
scal
e w
as p
ropo
sed
afte
r st
udie
s on
the
ox
idat
ion
of
Fe-
Cr
allo
ys
(0-2
5%
Cr)
, w
hich
w
ere
cond
ucte
d in
A
r10%
H2O
ov
er
a te
mpe
ratu
re r
ange
of
700-
1100
°C
. S
cale
s co
nsis
ting
of
thre
e di
stin
ct z
ones
wer
e ob
serv
ed,
an o
uter
zon
e co
mpo
sed
of o
ne o
r m
ore
laye
rs o
f w
usti
te,
an i
nner
por
ous
scal
e co
ntai
ning
w
usti
te a
nd a
n ir
on-c
hrom
ium
spi
nel-
oxid
e, a
nd a
sub
scal
e of
iro
n-ch
rom
ium
spi
nel
46.
7.2
O
xid
an
t-g
as
Pen
etra
tion
Mec
ha
nis
m
In o
xida
tion
stu
dies
con
duct
ed b
y Ik
eda
and
Nii
49-5
0 on
Fe-
Cr
allo
ys (
5-30
%C
r) i
n dr
y ox
ygen
and
in
O2-
10%
H2O
at
750
°C a
nd 9
00 °
C, i
t w
as o
bser
ved
that
all
oys
wit
h ch
rom
ium
co
nten
t gr
eate
r th
an 1
5% h
ad a
mas
s ga
in a
n or
der
of m
agni
tude
gre
ater
in
wet
oxy
gen
than
in
dry
oxy
gen.
T
wo
poss
ible
rea
ctio
n m
echa
nism
wer
e co
mpa
red,
i.e
. th
e di
ssoc
iati
on
mec
hani
sm (
Sec
tion
7.1
abo
ve)
and
oxid
ant-
gas
pene
trat
ion.
T
he a
utho
rs s
how
ed b
y si
mpl
e ga
s ki
neti
cs b
ased
cal
cula
tion
s th
at t
he d
isso
ciat
ion
mec
hani
sm w
as n
ot a
n ap
prop
riat
e ex
plan
atio
n, a
nd t
hus
prop
osed
the
oxi
dant
-gas
pen
etra
tion
mec
hani
sm.
Thi
s ba
sica
lly
stat
es
that
via
the
dev
elop
men
t of
mic
rocr
acks
and
por
es i
n th
e sc
ale,
oxy
gen
and
wat
er v
apou
r ca
n pa
ss d
irec
tly
to t
he m
etal
sur
face
, as
sum
ing
the
size
and
fre
quen
cy o
f th
e cr
acki
ng i
s la
rge.
F
urth
er c
alcu
lati
ons
by H
onda
et
al
51 h
ave
conf
irm
ed t
hat
the
supp
ly o
f ox
ygen
via
wat
er
vapo
ur w
as f
aste
r th
an i
n dr
y at
mos
pher
es,
alth
ough
it
was
sti
ll i
nsuf
fici
ent
to a
ccou
nt f
or a
ll
the
obse
rved
wei
ght
gain
s –
thus
cau
sing
fur
ther
dou
bt r
egar
ding
the
dis
soci
atio
n m
echa
nism
.
Oxi
dati
on w
ould
pro
ceed
in
the
foll
owin
g m
anne
r.
Init
iall
y a
chro
mia
lay
er w
ould
cov
er t
he
allo
y su
rfac
e.
Gas
pen
etra
ting
thr
ough
a c
rack
or
pore
int
o a
void
cou
ld i
ncre
ase
the
part
ial
pres
sure
of
oxyg
en w
ithi
n th
e vo
id i
n su
ch a
way
tha
t th
e ir
on i
s ox
idiz
ed.
The
res
ulta
nt
mix
ed-o
xide
sca
le w
ould
not
be
able
to
prev
ent
outw
ard
diff
usio
n of
iro
n io
ns,
and
so a
n ir
on-r
ich
oute
r sc
ale
is l
ikel
y to
for
m.
The
pre
senc
e of
the
se m
icro
crac
ks o
r po
res
was
co
nfir
med
by
sulp
hur
deco
rati
on.
Ik
eda
and
Nii
50
ob
serv
ed
that
un
der
dry
oxyg
en
cond
itio
ns
the
gas
pene
trat
ion
was
in
freq
uent
, w
hile
in
wet
oxy
gen
cond
itio
ns i
t w
as a
lway
s ob
serv
ed.
It w
as s
ugge
sted
tha
t th
e w
ater
vap
our
caus
ed m
ore
freq
uent
sca
le c
rack
ing
and
also
pre
vent
ed t
he s
cale
fro
m h
eali
ng,
ther
eby
acce
lera
ting
the
oxid
atio
n pr
oces
s.
7.3
F
orm
ati
on
an
d V
ola
tili
sati
on
of
Fe(
OH
) 2
Sur
man
and
Cas
tle
52-5
3 pro
pose
d a
mec
hani
sm b
ased
on
form
atio
n an
d vo
lati
lisa
tion
of
Fe(
OH
) 2 t
o ac
coun
t fo
r th
e ac
cele
rate
d ox
idat
ion
of c
hrom
ium
ste
els
in t
he p
rese
nce
of w
ater
va
pour
. T
hey
sugg
este
d th
at t
he r
ate-
dete
rmin
ing
step
cou
ld b
e on
e of
thr
ee t
hing
s –
O
utw
ard
diff
usio
n of
iro
n ca
tion
s to
the
oxi
de/g
as i
nter
face
In
war
d di
ffus
ion
of o
xyge
n an
ions
to
the
met
al/o
xide
int
erfa
ce
Vap
our-
phas
e di
ffus
ion
of F
e(O
H) 2
to
the
oxid
e/ga
s in
terf
ace
The
mod
el t
hat
they
use
d as
sum
ed t
he f
ollo
win
g ph
ase
boun
dary
rea
ctio
ns f
or t
he f
orm
atio
n an
d di
ssoc
iati
on o
f th
e vo
lati
le h
ydro
xide
.
NP
L R
epor
t M
AT
C(A
)90
Pag
e 31
of
39
Met
al/o
xide
inte
rfac
e,
)(
2)
(4
3)
(2
)(
)(
2)
(2
)(
2)
(
44
3
)(
2
gs
gs
gg
gs
HO
Fe
OH
Fe
HO
HF
eO
HF
e
Oxi
de/g
as in
terf
ace,
)(
2)
(2
)(
43
)(
22
)(
gg
sg
HO
HO
Fe
OH
Fe
For
eac
h of
the
thr
ee m
echa
nism
s, c
ompa
riso
ns w
ere
mad
e be
twee
n th
e ex
peri
men
tal
valu
e fo
r th
e te
mpe
ratu
re d
epen
denc
e of
the
par
abol
ic r
ate
cons
tant
and
tha
t of
the
the
oret
ical
va
lue.
T
he t
heor
etic
al v
alue
for
the
vap
our
phas
e di
ffus
ion
mod
el g
ave
the
best
fit
and
was
co
nsid
ered
the
mos
t li
kely
mec
hani
sm,
alth
ough
qua
ntit
ativ
ely
the
pred
icte
d ra
te c
onst
ants
ar
e ov
er a
n or
der
of m
agni
tude
too
low
. T
his
mec
hani
sm h
as a
lso
been
cit
ed b
y ot
her
wor
kers
54-5
5 , w
hils
t K
lein
et
al
56 ha
ve d
ispu
ted
the
vali
dity
of
Sur
man
and
Cas
tle’
s w
ork.
T
he m
ain
obje
ctio
n w
as t
hat
in s
teel
s co
ntai
ning
nic
kel
and
coba
lt t
he o
uter
oxi
de l
ayer
s di
d no
t co
ntai
n ei
ther
of
thes
e el
emen
ts a
ltho
ugh
the
vola
tili
ty o
f ni
ckel
and
cob
alt
hydr
oxid
e is
si
mil
ar t
o ir
on h
ydro
xide
. 7
.4
Fo
rma
tio
n a
nd
Vo
lati
lisa
tio
n o
f C
rO2(O
H) 2
Thi
s m
echa
nism
wou
ld s
ugge
st t
hat
the
evap
orat
ion
of v
olat
ile
chro
miu
m s
peci
es p
rim
aril
y al
ong
the
grai
n bo
unda
ries
acc
ount
s fo
r sc
ale
crac
king
and
spa
llat
ion
of o
xide
sca
les
in t
he
pres
ence
of
wat
er v
apou
r.
Arm
anet
et
al
57 e
xpos
ed a
sel
ecti
on o
f al
loys
to
pure
oxy
gen,
air
an
d w
et a
ir.
The
y fo
und
that
the
oxi
dati
on o
f N
i-20
Cr
in b
oth
dry
air
and
wet
air
res
ulte
d in
th
e fo
rmat
ion
of t
hree
oxi
des.
T
hese
wer
e C
r 2O
3, N
iO a
nd t
he s
pine
l ox
ide
NiC
r 2O
4.
Whi
lst
in t
he d
ry a
ir t
he N
iO p
hase
gra
dual
ly d
isap
pear
ed w
ith
tim
e by
rea
ctio
n w
ith
chro
mia
to
gene
rate
the
spi
nel,
in t
he w
et a
tmos
pher
e, t
he N
iO p
ersi
sted
. S
igni
fica
nt c
rack
ing
and
spal
lati
on i
s re
port
ed t
o ha
ve o
ccur
red.
It
is
sugg
este
d th
at d
urin
g vo
lati
lisa
tion
com
poun
ds
rich
in
chro
miu
m w
ould
exe
rt a
n ov
er-p
ress
ure,
whi
ch w
ould
cau
se t
he o
xide
lay
er t
o bu
rst.
W
hen
the
chro
mia
-lay
er w
as c
onti
nuou
s at
the
all
oy/o
xide
int
erfa
ce,
com
pres
sive
str
esse
s w
ould
be
indu
ced
caus
ing
brea
kdow
n of
the
NiO
and
NiC
r 2O
4 la
yers
. T
he c
hrom
ia l
ayer
is
then
in
cont
act
wit
h th
e at
mos
pher
e an
d w
ould
vol
atil
ise
as C
rO3
and
CrO
2(O
H).
T
he a
lloy
no
w d
eple
ted
in c
hrom
ium
wou
ld r
eoxi
dise
and
a n
ew l
ayer
of
NiO
, an
d ev
entu
ally
spi
nel,
w
ould
dev
elop
. T
his
proc
ess
wou
ld c
onti
nue
in s
uch
a m
anne
r so
tha
t th
e st
eady
sta
te s
een
duri
ng d
ry o
xida
tion
wou
ld n
ot b
e at
tain
ed.
)(
22
23
)(
22
23
2
)(3
23
2
21
)(
22
)(
222
3
g
g
g
OO
HC
rOO
HC
rO
OH
CrO
OH
OO
Cr
CrO
OO
Cr
7.5
C
ha
ng
es i
n t
he
Ox
ide
Def
ect
Str
uct
ure
via
Pro
ton
Dis
solu
tio
n
Wat
er v
apou
r m
ay h
ave
an e
ffec
t on
the
def
ect
stru
ctur
e an
d de
fect
-dep
enda
nt p
rope
rtie
s of
m
any
oxid
e sy
stem
s.
It i
s su
gges
ted
that
wat
er v
apou
r se
rves
as
a so
urce
of
hydr
ogen
, whi
ch
NP
L R
epor
t M
AT
C(A
)90
Pag
e 32
of
39
diss
olve
s as
pro
tons
in
the
met
al o
xide
. A
lso
wat
er v
apou
r m
ay a
ffec
t th
e m
ajor
ity-
defe
ct
dom
inat
ed p
rope
rtie
s su
ch a
s di
ffus
ion-
cont
roll
ed t
rans
port
of
reac
tant
s th
roug
h gr
owin
g sc
ales
, or
min
orit
y do
min
ated
def
ects
suc
h as
hig
h te
mpe
ratu
re c
reep
. G
aler
ie e
t a
l 58
hav
e co
mpa
red
the
oxid
atio
n of
met
als
in o
xyge
n an
d in
wat
er v
apou
r.
Tw
o m
ain
area
s of
int
eres
t w
ere
iden
tifi
ed;
thes
e w
ere
the
natu
re a
nd e
ffec
t of
the
maj
or p
oint
de
fect
s in
the
oxi
de, a
nd t
he e
ffec
t th
at t
he a
cidi
ty o
f th
e ox
ide
surf
ace
had.
In
exa
min
ing
the
natu
re o
f th
e po
int
defe
cts,
Gal
erie
et
al
cons
ider
ed p
oint
def
ects
suc
h as
su
bsti
tion
al
site
s an
d in
ters
titi
al
site
s an
d gr
ain
boun
dary
de
fect
s.
W
ater
va
pour
w
as
cons
ider
ed t
o en
hanc
e th
e ox
idat
ion
of m
etal
s.
Tha
t is
pro
vide
d th
at o
xyge
n w
as a
mon
g th
e m
ost
mob
ile
spec
ies
in t
he f
orm
ed o
xide
. T
he s
olub
ilit
y of
hyd
roge
n in
the
met
alli
c su
bstr
ate
was
als
o de
emed
to
be o
f im
port
ance
, si
nce
met
als
that
wer
e m
ost
affe
cted
by
the
wat
er
vapo
ur w
ere
thos
e th
at e
xhib
ited
hyd
roge
n so
lubi
lity
.
The
rat
e-co
ntro
llin
g st
ep i
n ox
idat
ion
is t
he t
rans
port
of
oxyg
en t
hrou
gh t
he o
xide
via
hy
drox
yl d
efec
ts.
Thi
s be
ing
the
case
, it
is
like
ly t
hat
the
gene
rati
on o
f O
H s
peci
es o
n th
e ox
ide
surf
ace
is a
lso
a ve
ry i
mpo
rtan
t fa
ctor
. I
ndee
d w
ater
ads
orpt
ion
stud
ies
59-6
1 hav
e sh
own
that
an
oxid
e su
rfac
e ex
pose
d to
ste
am i
s ea
sily
cov
ered
wit
h hy
drox
yl s
peci
es,
but
oxyg
en s
peci
es a
re m
uch
mor
e di
ffic
ult
to f
orm
. T
o fo
rm o
xyge
n sp
ecie
s th
e su
rfac
e m
ust
fix
the
OH
par
ticl
e by
its
oxy
gen
elec
tron
pai
rs, w
hich
lea
ds t
o a
high
pol
ariz
atio
n ef
fect
the
reby
pr
omot
ing
the
disa
ssoc
iati
on o
f th
e se
cond
O-H
bon
d.
To
achi
eve
this
the
sur
face
mus
t ex
hibi
t ac
idic
pro
pert
ies.
Gal
erie
et
al
58 h
ave
show
n th
at p
ure
met
al s
peci
es t
hat
did
not
have
ac
idic
oxi
des
had
very
slo
w o
xida
tion
rat
es i
n w
ater
vap
our
com
pare
d to
oxy
gen.
In
the
se
circ
umst
ance
s it
is
sugg
este
d th
at t
he o
xida
tion
rat
e is
con
trol
led
by t
he d
ecom
posi
tion
of
OH
sp
ecie
s in
the
abs
orbe
d ph
ase
as s
how
n be
low
:
22
2H
sO
sO
H
w
here
s i
s an
ads
orpt
ion
site
on
the
oxid
e su
rfac
e. T
his
wou
ld y
ield
a l
inea
r ra
te l
aw a
nd t
hus
the
effe
ct o
f th
e w
ater
vap
our
pres
sure
wou
ld f
ollo
w:
2
.k
r
w
here
r i
s th
e re
acti
on r
ate,
k t
he r
ate
cons
tant
and
t
he f
ract
ion
of t
he o
xide
sur
face
cov
ered
by
OH
spe
cies
, thi
s is
giv
en b
y L
angm
uir’
s eq
uili
briu
m e
quat
ion:
KP
KP
1
w
here
P a
nd K
are
the
wat
er v
apou
r pr
essu
re a
nd e
quil
ibri
um c
onst
ants
, thu
s
2
1K
P
KP
kr
In t
he c
ase
of a
cidi
c ox
ides
Gal
erie
et
al
repo
rt t
hat
the
rate
of
OH
sur
face
dec
ompo
siti
on w
as
high
eno
ugh
to s
uppl
y ox
ide
ions
to
the
scal
e as
rap
idly
as
they
wer
e be
ing
cons
umed
, an
d th
e re
acti
on r
ate
was
not
lim
ited
by
the
deco
mpo
siti
on.
A g
ener
al r
ule
is p
ropo
sed:
“W
ater
va
pour
may
rea
ct m
ore
rapi
dly
wit
h m
etal
s th
an o
xyge
n pr
ovid
ed t
hat
the
form
ed o
xide
can
NP
L R
epor
t M
AT
C(A
)90
Pag
e 33
of
39
grow
by
tran
spor
t of
hyd
roxy
l io
ns.
If t
his
is n
ot p
ossi
ble,
the
rat
e of
the
rea
ctio
n w
ill
depe
nd
on t
he s
urfa
ce a
cidi
ty o
f th
e ox
ide,
i.e
. the
low
er t
he a
cidi
ty –
the
slo
wer
the
rea
ctio
n” 58
.
It i
s un
clea
r as
to
whi
ch m
echa
nism
to
pref
er a
s no
ne o
f th
e su
gges
ted
mec
hani
sms
seem
to
adeq
uate
ly e
xpla
in a
ll o
f th
e ob
serv
ed b
ehav
iour
.
8
D
iscu
ssio
n a
nd
Co
ncl
usi
on
s
Alt
houg
h th
ere
is a
lar
ge b
ody
of w
ork
conc
erne
d w
ith
oxid
atio
n in
ste
am o
r hi
gh m
oist
ure,
it
is d
iffi
cult
to
extr
act
cohe
rent
the
mes
eve
n w
ithi
n a
sing
le a
lloy
cla
ss.
Gal
erie
58 s
ugge
sted
th
e m
ajor
rea
sons
beh
ind
this
con
fusi
on a
s be
ing:
Wit
hin
indu
stri
al s
itua
tion
s ac
tual
pur
e w
ater
vap
our,
wit
h a
max
imum
oxy
gen
part
ial
pres
sure
equ
al t
o it
s de
com
posi
tion
pre
ssur
e, i
s se
ldom
, if
ever
enc
ount
ered
.
Atm
osph
eres
co
nsis
ting
of
pu
re
wat
er
vapo
ur
are
very
di
ffic
ult
to
prod
uce
and
mai
ntai
n, t
hus
repo
rted
obs
erva
tion
s w
ithi
n th
e li
tera
ture
are
sub
ject
to
caut
ion.
As
a co
nseq
uenc
e of
the
tw
o po
ints
alr
eady
men
tion
ed,
muc
h of
the
rep
orte
d w
ork
deal
s w
ith
atm
osph
eres
con
sist
ing
of O
2/H
2O, a
ir/H
2O o
r H
2/H
2O m
ixtu
res.
T
he a
ppar
ent
lack
of
basi
c un
ders
tand
ing
of s
team
oxi
dati
on i
s un
ders
tand
able
giv
en t
he
com
plex
itie
s en
coun
tere
d.
F
urth
er
wor
k is
re
quir
ed
to
enha
nce
the
curr
ent
leve
l of
un
ders
tand
ing,
in
part
icul
ar t
he i
nflu
ence
of
labo
rato
ry t
est
proc
edur
es o
n th
e re
sult
ant
data
. T
he p
reci
se i
n-se
rvic
e co
ndit
ions
are
dif
ficu
lt i
f no
t im
poss
ible
to
repr
oduc
e in
the
lab
orat
ory
and
som
e de
gree
of
sim
plif
icat
ion
is n
eces
sary
. S
ever
al e
xpos
ure
proc
edur
es a
re i
n co
mm
on
use
in t
he l
abor
ator
y –
in a
scen
ding
ord
er o
f co
mpl
exit
y th
ese
are:
Wat
er v
apou
r in
a c
arri
er g
as (
usua
lly
argo
n)
Flo
win
g st
eam
at
atm
osph
eric
pre
ssur
e S
tati
c st
eam
at
high
pre
ssur
e F
low
ing
stea
m a
t hi
gh p
ress
ure.
How
ever
, th
ere
is l
ittl
e ev
iden
ce o
f co
mpa
riso
ns b
etw
een
the
diff
eren
t te
chni
ques
. S
uch
a co
mpa
riso
n be
twee
n th
e di
ffer
ent
met
hods
wit
h in
-ser
vice
exp
osur
e w
ould
be
of g
reat
ben
efit
to
the
ind
ustr
y as
it
wou
ld g
ive
clea
r gu
idan
ce a
s to
whi
ch m
etho
d pr
oduc
es o
xide
sca
les
whi
ch m
ost
clos
ely
rese
mbl
e th
ose
seen
fro
m r
eal
expo
sure
s.
The
rev
iew
has
als
o sh
own
that
sub
tle
chan
ges
in t
he a
lloy
com
posi
tion
can
hav
e m
arke
d ef
fect
s on
oxi
dati
on r
esis
tanc
e in
ste
am a
tmos
pher
es,
for
exam
ple
the
addi
tion
of
Si
or r
are
eart
h el
emen
ts.
Fur
ther
inv
esti
gati
on o
f th
e ef
fect
s of
all
oy c
ompo
siti
on c
hang
es c
ould
be
bene
fici
al i
n te
rms
of f
utur
e al
loy
deve
lopm
ent
and
plan
t de
sign
.
In a
ddit
ion
to t
hese
poi
nts
it i
s im
port
ant
to r
emem
ber
that
oxi
dati
on i
s a
dyna
mic
pro
cess
, th
e pr
esen
ce o
f ox
ide
scal
es w
ill
act
to r
educ
e th
e th
erm
al d
iffu
sivi
ty o
f co
mpo
nent
s.
Wit
hin
the
cour
se
of
this
re
view
ve
ry
litt
le
info
rmat
ion
rega
rdin
g th
e th
erm
al
cond
ucti
vity
of
co
mpo
nent
s w
ith
oxid
e sc
ales
was
app
aren
t.
Thu
s a
furt
her
aven
ue o
f w
ork
to a
id i
n th
e li
feti
me
eval
uati
on
of
com
pone
nts
mus
t in
clud
e so
me
acti
vity
on
th
erm
al
cond
ucti
vity
NP
L R
epor
t M
AT
C(A
)90
Pag
e 34
of
39
mea
sure
men
t of
oxi
de s
cale
s as
the
sca
le g
row
s.
Dat
a fr
om s
uch
mea
sure
men
ts w
ould
be
an
inva
luab
le t
ool
for
mod
elle
rs t
o us
e in
the
eva
luat
ion
of c
ompo
nent
lif
e.
The
mai
n po
ints
fro
m t
he r
evie
w a
re s
umm
aris
ed b
elow
: In
gen
era
l
Incr
easi
ng C
r co
nten
t im
prov
es t
he s
team
oxi
dati
on r
esis
tanc
e T
here
is
no c
onsi
sten
t ef
fect
of
stea
m p
ress
ure
Fo
r lo
w a
lloy
(1-3
%C
r) s
teel
s
Gro
wth
kin
etic
s ar
e af
fect
ed b
y th
e fl
ow r
ate
of t
he s
team
atm
osph
ere
Gro
wth
kin
etic
s ra
nge
from
sub
par
abol
ic a
t lo
w t
empe
ratu
re (
500
°C)
to a
ppro
achi
ng
line
ar a
t 65
0 °C
T
he
pres
ence
of
w
ater
va
pour
in
th
e te
st
atm
osph
ere
may
in
crea
se
or
decr
ease
co
rros
ion
rate
, dep
endi
ng o
n te
st t
empe
ratu
re
Fo
r m
art
ensi
tic
(9-1
2%
Cr)
ste
els
Add
itio
ns o
f S
i, T
i an
d Y
im
prov
e th
e st
eam
oxi
dati
on r
esis
tanc
e T
he a
ddit
ion
of s
mal
l (
<1%
) am
ount
s of
nic
kel
redu
ces
stea
m o
xida
tion
res
ista
nce
Fo
r a
ust
enit
ic s
teel
s
Oxi
dati
on r
ates
inc
reas
e un
der
high
pre
ssur
e at
mos
pher
es
Fin
e gr
ain
size
im
prov
es o
xida
tion
res
ista
nce
by i
ncre
asin
g th
e su
pply
of
Cr
to t
he
surf
ace
Fo
r N
i a
nd
Co
ba
se s
uper
all
oys
Lit
tle
info
rmat
ion
exis
ts i
n th
e pu
blis
hed
lite
ratu
re r
egar
ding
the
ste
am o
xida
tion
re
sist
ance
of
this
cla
ss o
f al
loy
In c
oncl
usio
n, t
his
revi
ew h
as s
how
n th
e ne
ed f
or a
sys
tem
atic
stu
dy o
f th
e ef
fect
s of
all
oy
com
posi
tion
, la
bora
tory
tes
t pr
oced
ure
and
stea
m c
hem
istr
y on
ste
am o
xida
tion
beh
avio
ur.
Cri
tica
l te
sts
are
requ
ired
to
esta
blis
h th
e m
echa
nism
s op
erat
ing
in t
he d
iffe
rent
all
oys
and
whe
ther
the
se a
re a
ffec
ted
by t
he e
xper
imen
tal
para
met
ers.
O
ne p
ossi
ble
rout
e is
thr
ough
m
odel
ling
and
ana
lysi
s of
the
ste
am a
tmos
pher
e to
det
erm
ine
the
pres
ence
or
othe
rwis
e of
vo
lati
le
spec
ies
in
the
envi
ronm
ent.
Oth
er
crit
ical
m
easu
rem
ents
ar
e th
e co
mpo
siti
on,
mic
rost
ruct
ure
and
grow
th k
inet
ics
of t
he o
xide
s th
at a
re f
orm
ed a
s a
func
tion
of
expo
sure
pr
oced
ure
and
allo
y co
mpo
siti
on.
Ack
no
wle
dg
emen
ts
Thi
s w
ork
was
car
ried
out
as
part
of
proj
ect
LP
M2.
1 on
the
Pri
nci
ple
s o
f S
tea
m O
xid
ati
on,
whi
ch i
s pa
rt o
f th
e L
PM
pro
gram
me
on L
ife
Per
form
ance
of
Mate
rials
, fu
nded
by
the
UK
D
epar
tmen
t of
Tra
de a
nd I
ndus
try.
T
he a
utho
rs a
re g
rate
ful
to T
. B
. G
ibbo
ns a
nd t
o S
. R
. J.
Sau
nder
s fo
r th
eir
crit
ical
rev
iew
of
the
man
uscr
ipt.
NP
L R
epor
t M
AT
C(A
)90
Pag
e 35
of
39
9
Ref
eren
ces
1 H
.L.S
olbe
rg,
G.A
. H
awki
ns
and
A.A
. P
otte
r.
“C
orr
osi
on
of
Un
stre
ssed
S
teel
Sp
ecim
ens
by
Hig
h T
emp
era
ture
Ste
am
”,
Tra
nsa
ctio
ns
of
the
Am
eric
an S
oci
ety
of
Mec
ha
nic
al
En
gin
eers
, 194
2, 6
4, 3
03.
2 F
. E
berl
e an
d C
.H.
And
erso
n.
“S
cali
ng B
ehavio
ur
of
Su
per
hea
ter
Tu
be
All
oys
in
AS
ME
H
igh
-Tem
per
atu
re
Ste
am
R
esea
rch
T
ests
a
t 1
10
0-1
50
0F
”,
Journ
al
of
Engin
eeri
ng P
ow
er, 1
962,
84,
223
. 3
G.
von
Hei
erm
ann
et a
l, D
am
pfe
rzeu
ger
fü
r fo
rtg
esch
ritt
ene
Da
mp
fpa
ram
eter
. V
GB
Kra
ftw
erks
tech
nik
73
(199
3). H
. 8. S
. 678
-689
. 4
SU
MIT
OM
O
ME
TA
L
IND
US
TR
IES
L
td,
"S
team
O
xid
ati
on
on
C
r-M
o-S
teel
Tu
bes
”, P
aper
No.
805
, 144
3A, 1
989.
5
V. L
epin
gle,
G. L
ouis
, D. P
etel
ot, B
. Lef
ebvr
e an
d J.
C. V
aill
ant,
“H
igh
Tem
per
atu
re
Co
rro
sio
n
Beh
av
iou
r o
f S
om
e B
oil
er
Ste
els
in
Pu
re
Wa
ter
Va
po
ur.
”
Hig
h
Tem
per
atu
re
Corr
osi
on
and
Pro
tect
ion
of
Mate
rials
5,
Mate
rials
Sci
ence
F
oru
m
Vol
s. 3
69-3
72, T
rans
Tec
h P
ubli
cati
ons,
Sw
itze
rlan
d, 2
001,
pp2
39-2
46.
6 M
. I.
Man
ning
and
E.
Met
calf
e, “
Ox
ida
tio
n o
f F
erri
tic
Ste
els
in S
tea
m”
, in
Pro
c
Con
f F
erri
tic
Ste
els
for
Fa
st
Rea
ctor
Ste
am
G
ener
ato
rs”
, B
NE
S,
Lon
don
1978
pp
378-
382.
7
J. C
. G
ries
s, W
. A
. M
axw
ell.
“
Th
e L
on
g-T
erm
Oxid
ati
on
of
Sel
ecte
d A
llo
ys
in
Su
per
hea
ted
S
team
at
482
an
d
538°C
”.
O
RN
L-5
771,
O
ak
Rid
ge
Nat
iona
l L
abor
ator
y, 1
981.
8
D.
Gam
bier
, “
Th
èse
de
Do
cteu
r,
Un
iver
sité
d
e T
ech
no
log
ie
de
Co
mp
iég
ne”
, F
ranc
e, 1
997.
9
J. T
avas
t, E
xp
erie
nce
of
au
sten
itic
mate
rials
in
fo
ssil
fu
el b
oil
ers.
Sti
ftel
sen F
ür
Vä
rmet
ekn
isk
Fo
rskn
ing. O
ctob
er 1
989.
SV
F-3
56.
10
N. O
tsuk
a, H
. Fuj
ikaw
a, C
orr
osi
on
, 199
1, 4
7, 4
, pp.
240
-248
11
F
. A
rman
et,
J.H
. D
avid
son,
“L
es A
cier
s In
ox
yd
ab
les”
, P
. L
acom
be,
B.
Bar
oux,
G.
Bér
ange
r E
ds, e
s E
d. D
e P
hys
ique,
199
0, p
p. 4
46-4
89
12
M.
Mon
gom
ery
and
A.
Kar
lsso
n, “
Su
rvey
of
Oxid
ati
on
in
Ste
am
sid
e C
on
dit
ion
s”,
VG
B K
raft
wer
kste
chn
ik, 7
5, 1
995,
pp.
235
-240
. 13
N
. B
irks
an
d G
.M.
Mey
er:
“In
tro
du
ctio
n
to
Hig
h
Tem
per
atu
re
Ox
ida
tio
n
of
Met
als
”, E
dwar
d A
rnol
d, L
ondo
n, 1
982.
14
R
.K.S
. R
aman
, M
eta
llu
rgic
al
an
d M
ate
ria
ls T
ran
sact
ion
s A
, V
olum
e 30
A,
Aug
ust
1999
.
NP
L R
epor
t M
AT
C(A
)90
Pag
e 36
of
39
15
S.
R.
Pat
erso
n, R
. S
. M
oser
and
T.
W.
Ret
tig,
“In
tera
ctio
n o
f Ir
on
Base
d M
ate
rials
Wit
h W
ate
r a
nd
Ste
am
- O
xid
ati
on
of
Bo
iler
Tu
bin
g”, 1
992
Pap
er 8
. 16
A
. A
rízt
egui
, T
. G
ómez
-Ace
bo,
F.
Cas
tro.
Ste
am
O
xid
ati
on
o
f F
erri
tic
Ste
els:
Kin
etic
s a
nd
M
icro
stru
ctu
re.
Bole
tín de
la Soci
edad E
spañola
de
Cer
ám
ica y
Vid
rio. V
ol. 3
9, N
úm. 3
May
-Jun
e 20
00. p
p. 3
05-3
11.
17
T. S
umid
a, T
. Iku
no, N
. Ots
uka,
T. S
abur
i, “
Hig
h t
emp
eratu
re o
xid
ati
on
beh
avio
ur
of
2.2
5%
C
r-1
% M
o st
eel
bo
iler
tu
bes
in
lo
ng
-ter
m ex
po
sure
to
su
per
hea
ted
stea
m”
, Mate
r. T
ran
s., J
IM, 3
6, 1
372-
1378
(19
95).
18
H
. T
. A
bulu
wef
a, R
. I.
L.
Gut
hrie
and
F.
Aje
rsch
, “
Ox
ida
tio
n o
f lo
w c
arb
on
ste
el i
n
mu
ltic
om
po
nen
t g
ase
s:
Pa
rt
I.
Rea
ctio
n
mec
han
ism
s d
uri
ng
isoth
erm
al
ox
ida
tio
n”
, Met
all
. M
ate
r. T
ran
s. A
, 28A
, 163
3-16
41 (
1997
).
19
J. C
. N
ava-
Paz
and
R.
Kno
edle
r, “
Ma
teri
als
fo
r A
dv
an
ced
P
ow
er E
ng
inee
rin
g
19
98
”, e
ds J
Lec
ompt
e-B
ecke
rs e
t al
, En
ergie
teck
nik
, Ju
lich
199
8 p4
51-4
59
20
L.
O.
Bue
no,
L M
arin
o.
“H
igh
-Tem
per
atu
re O
xid
ati
on
Beh
av
iou
r o
f 2
¼C
r-1
Mo
Ste
el i
n A
ir-P
art
2:
Sca
le G
row
th,
Met
al
Loss
Kin
etic
s, a
nd
Str
ess
En
han
cem
ent
Fa
cto
rs D
uri
ng
Cre
ep T
esti
ng
”.
Journ
al
of
Pre
ssure
Ves
sel
Tes
tin
g, F
ebru
ary
2001
, V
ol. 1
23, p
p. 9
7-10
4.
21
A.
S.
Kha
nna,
B.
B.
Jha,
and
B.
Raj
. “
Det
ecti
on
of
Bre
ak
aw
ay
Ox
ida
tio
n a
nd
Sp
all
ing
in
th
e O
xid
e S
cale
s o
f 2
¼
Cr-
1M
o
Ste
el
Usi
ng
A
cou
stic
E
mis
sio
n
Tec
hn
iqu
e”, O
xid
. M
et. 1
985,
23,
pp.
159
-176
. 22
N
. J.
S
imm
s,
J.
A.
Lit
tle.
“
Sca
le
Gro
wth
o
n
2
¼C
r-1
Mo
S
teel
”,
Ma
ter.
S
ci.
Tec
hn
ol.
, 198
9,4,
pp.
113
3-11
39.
23
F.
Abe
, M
. Ig
aras
hi,
S.
Wan
ikaw
a,
M.
Tab
uchi
, T
. It
agak
i,
K.
Kam
ura
and
K Y
amag
uchi
, “
R&
D o
f a
dv
an
ced
Fer
riti
c st
eels
of
65
0 °
C U
SC
Bo
iler
s”,
Pro
c, o
f th
e 5t
h In
tern
atio
nal
Cha
rles
Par
sons
tur
bine
con
fere
nce,
Eds
, A
Str
ang,
W M
Ban
ks,
R D
Con
roy
G M
McC
olvi
n J
C N
eal
and
S S
imps
on,
IOM
Com
mun
icat
ions
Ltd
., 20
00, p
129-
142.
24
P
. H
urst
and
H.
C.
Cow
en,
“T
he
Ox
ida
tio
n o
f 9
Cr-
Mo a
nd
Oth
er S
teel
s in
6.9
MN
/m2 S
team
at
748 a
nd
823°K
,” p
aper
62
in P
roc.
Int
. Con
f. O
n F
erri
tic
Ste
els
for
Fas
t R
eact
or S
team
Gen
erat
ors,
Bri
tish
Nuc
lear
Ene
rgy
Soc
iety
, Lon
don,
197
7.
25
M.
Igar
ashi
, S
. M
unek
i, H
. K
utsu
mi,
T.
Itag
aki,
N.
Fuj
itsu
na a
nd F
. A
be.
“A
new
con
cep
t fo
r st
ren
gth
enin
g o
f a
dv
an
ced
fer
riti
c st
eels
for
US
C p
ow
er p
lan
t”,
Pro
c,
of t
he 5
th I
nter
nati
onal
Cha
rles
Par
sons
tur
bine
con
fere
nce,
Eds
, A
Str
ang,
W M
B
anks
, R
D C
onro
y G
M M
cCol
vin
J C
Nea
l an
d S
Sim
pson
, IO
M C
omm
unic
atio
ns
Ltd
., 20
00, p
336-
347
. 26
S
. H
enry
, A
. G
aler
ie,
L.
Ant
oni,
A
bn
orm
al
Ox
ida
tio
n
of
Sta
bil
ized
F
erri
tic
Sta
inle
ss S
teel
s in
Wate
r V
ap
ou
r, H
igh T
emper
atu
re C
orr
osi
on a
nd P
rote
ctio
n o
f
Ma
teri
als
5, M
ate
ria
ls S
cien
ce F
oru
m V
ols.
369
-372
, pp.
353
-360
.
NP
L R
epor
t M
AT
C(A
)90
Pag
e 37
of
39
27
Mur
ata
et a
l, pr
ivat
e co
mm
unic
atio
n vi
a K
-H M
ayer
. 28
D
.V.
Tho
rnto
n, K
.H.
May
er.
“N
ew
Mate
rials
fo
r A
dvan
ced
S
team
T
urb
ines
”.
Pro
ceed
ings
of
the
4th I
nter
nati
onal
Cha
rles
Par
sons
Tur
bine
Con
fere
nce.
29
Y
. O
togu
ro,
M.
Sak
akib
ara,
T.
Sai
to,
H.
Ito
and
Y.
Inou
e,.
Ox
ida
tio
n B
eha
vio
ur
of
Au
sten
itic
Hea
t-re
sist
ing
Ste
els
in a
Hig
h T
emp
era
ture
an
d H
igh
Pre
ssu
re S
tea
m
En
vir
on
men
t. T
ran
sact
ion
s IS
IJ, V
ol. 2
8, 1
988,
pp.
761
-768
. 30
H
. A
stem
an,
K.
Seg
erda
hl,
J. –
E.
Sve
nsso
n an
d L
. –G
. Jo
hans
son.
Th
e In
flu
ence
of
Wa
ter
Va
po
r o
n
the
Co
rro
sio
n
of
Ch
rom
ia-F
orm
ing
S
teel
, M
ate
ria
ls.
Hig
h
Tem
per
atu
re C
orr
osi
on a
nd P
rote
ctio
n o
f M
ate
rials
5,
Ma
teri
als
Sci
ence
Fo
rum
Vls
. 36
9-37
2 (2
001)
, pp.
277
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. 31
J.
E. C
roll
, G. R
. Wal
lwor
k. O
xid.
Met
., 4
(197
2), 3
, 121
. 32
D
. Cap
lan,
M. C
ohen
. C
orr
osi
on
, 15
(195
9), 1
41 t
. 33
L
. Ant
oni.
C
om
pa
riso
n o
f th
e C
ycl
ic-O
xid
ati
on
Beh
av
iou
r b
etw
een
AIS
I 3
04
an
d
Lo
w-N
ick
el A
ust
enit
ic S
tain
less
S
teel
. M
ate
rials
Sci
ence
F
oru
m V
ols.
369
-372
(2
001)
pp.
345
-352
. 34
I.
M.
Reh
n, C
orr
osi
on
Pro
ble
ms
in C
oa
l-F
ired
Bo
iler
Su
per
hea
ter
an
d R
ehea
ter
Tu
bes
: S
tea
m-S
ide
Ox
ida
tio
n
an
d
Ex
foli
ati
on
.
Rev
iew
a
nd
R
esu
lts
of
La
bo
rato
ry T
ests
. C
S-1
811,
Res
earc
h P
roje
ct 6
44-1
, Fin
al R
epor
t, A
pril
198
1.
35
H.
Ter
anis
hi
et
al,
Fin
e gra
ined
T
P347
Ste
el
Tu
bin
g
wit
h
Hig
h
Ele
va
ted
-
Tem
per
atu
re S
tren
gth
an
d C
orr
osi
on
Res
ista
nce
fo
r B
oil
er A
pp
lica
tio
ns .
T
he
Sum
itom
o S
earc
h 3
8, M
ay 1
989
pp. 6
3-74
36
H
. T
eran
ishi
et
al,
Ap
pli
cati
on
of
Fin
egra
ined
Au
sten
itic
Sta
inle
ss S
teel
Tu
bes
to
Su
per
hea
ters
in
Po
wer
Bo
iler
s .
Inte
rnat
iona
l C
onfe
renc
e on
Cre
ep,
Tok
yo A
pril
14
to 1
8. 1
986,
pp.
223
-238
. 37
P
. H. E
ffer
tz a
nd H
. Mei
sel,
“S
cali
ng
of
Hig
h T
emp
era
ture
Ste
els
in H
igh
Pre
ssu
re
Ste
am
aft
er
Lo
ng
S
erv
ice,
”
Ma
schin
ensc
haden
44
: 14
-20
(197
1)
(C.E
.G.B
. T
rans
lati
on 5
499)
. 38
L
. Ji
ang,
C.
R.
Bro
oks,
P.
K.
Lia
w a
nd D
. L
. K
lars
trom
. H
igh
-cy
cle
Fa
tig
ue
of
UL
TIM
ET
All
oy
. S
uper
all
oys
2000.
The
Min
eral
s, M
etal
s &
Mat
eria
ls S
ocie
ty,
2000
. pp
583-
591
. 39
S
. T
. S
chei
rer
and
R.
Vis
wan
atha
n, “
Ev
olu
tio
n o
f h
ot
sect
ion
tec
hn
olo
gy
”,
Pro
c A
SM
Mat
eria
ls S
olut
ions
con
fere
nce,
St
Lou
is O
ct 2
000,
AS
M I
nter
nati
onal
. 40
W
. E
. R
uthe
r an
d S
. G
reen
berg
, “
Co
rro
sio
n
of
Ste
els
an
d
Nic
kel
A
llo
ys
in
Su
per
hea
ted
Ste
am
”, J
. E
lect
roch
em. Soc.
, 196
4, V
ol. 1
11, p
p. 1
116-
1121
.
NP
L R
epor
t M
AT
C(A
)90
Pag
e 38
of
39
41
S.
Jans
son,
W.
Hüb
ner,
G.
Öst
berg
and
M.
de P
ourb
aix,
“O
xid
ati
on
Res
ista
nce
of
So
me
Sta
inle
ss S
teel
s a
nd
Nic
kel
-Ba
sed
All
oy
s in
Hig
h T
emp
era
ture
Wa
ter
an
d
Ste
am
”, B
r. C
orr
os.
J.,
1969
, Vol
. 4, J
anua
ry, p
p. 2
1-31
. 42
A
. W
. F
unen
busc
h, J
. G
. S
meg
gil
and
N.
S.
Bor
nste
in,
“R
eact
ive
elem
ent
–su
lph
ur
inte
ract
ion
an
d o
xid
e sc
ale
ad
her
ence
” M
etall
. T
ran
sA, 1
6, 1
985,
pp.
116
4-11
66.
43
A.
Str
awbr
idge
an
d P
. Y
. H
ou,
“R
eact
ive
elem
ents
in
o
xid
e sc
ale
a
dh
esio
n”
, M
ate
rials
at
Hig
h T
emper
atu
res,
12
, 199
4, p
p.17
7-18
1.
44
P.
Y.
Hou
and
J.
L.
Sm
iale
k, “
Th
e ef
fect
of
H2 a
nn
eal
on
th
e ad
hes
ion
of
Al 2
O3
sca
les
on
a
F
e 3A
l-b
ase
d
all
oy
”,
Mate
rials
at
Hig
h
Tem
per
atu
res,
1
7,
2000
, pp
. 79-
86.
45
I. G
. W
righ
t, B
. A
. P
int,
W.
Y.
Lee
, K
. B
. A
lexa
nder
and
K.
Prü
ssne
r, “
So
me
effe
cts
of
met
all
ic s
ub
stra
te c
om
po
siti
on
on
deg
rad
ati
on
of
ther
ma
l b
arr
ier
coa
tin
gs”
, in
Pro
c. H
igh t
emper
atu
re s
urf
ace
en
gin
eeri
ng
, E
ds J
Nic
holl
s an
d D
Ric
kerb
y, I
OM
C
omm
unic
atio
ns, 2
000,
Gra
de 9
5-11
3.
46
“A
sses
smen
t o
f S
team
Ox
ida
tio
n a
nd
Fir
esid
e C
orr
osi
on
of
9-1
2%
Cr
Ste
els”
, C
OS
T F
inal
Rep
ort.
47
C
. T
. F
ujii
and
R.
A.
Meu
ssne
r.
“T
he
Mec
ha
nis
ms
of
the
Hig
h-T
emp
era
ture
Ox
ida
tio
n
of
Iro
n-C
hro
miu
m
All
oy
s in
W
ate
r V
ap
ou
r”,
Jou
rna
l o
f th
e
Ele
ctro
chem
ica
l S
oci
ety,
196
4, 1
11, p
p 12
15.
48
C.T
. F
ujii
and
R.
A.
Meu
ssne
r.
“O
xid
e S
tru
ctu
res
Pro
du
ced
on
Iro
n-C
hro
miu
m
All
oy
s b
y a
Dis
soci
ati
ve
Mec
ha
nis
m”
, Journ
al
of
the
Ele
ctro
chem
ical
Soci
ety,
196
3,
110,
pp
1195
. 49
Y
. Ik
eda
and
K.
Nii
. “
Mec
ha
nis
m o
f A
ccel
era
ted
Ox
idati
on
on
Fe-
Cr
All
oy
s in
Wa
ter
Va
po
ur-
Co
nta
inin
g A
tmo
sph
eres
”, B
osh
oku
Gij
uts
u, 1
982,
31,
pp
156.
50
Y
. Ik
eda
and
K.
Nii
. “
Mic
rocr
ack
Gen
erati
on
an
d i
ts H
eali
ng
in
th
e O
xid
e S
cale
Fo
rmed
on
Fe-
Cr
All
oys”
, Oxi
da
tion
of
Met
als
, 197
8, 1
2, p
p. 4
87.
51
K.
Hon
da,
T.
Mar
uyam
a, T
. A
take
and
Y.
Sai
to.
“O
xid
ati
on
Beh
av
iou
r o
f S
US
43
0
Sta
inle
ss S
teel
in
Mo
ist
Atm
osp
her
es a
t 8
73K
”,
Oxi
dati
on o
f M
etals
, 19
92,
38,
pp 3
47.
52
P.
L.
Sur
man
and
J.
E.
Cas
tle.
“
Ga
s P
ha
se T
ran
spo
rt i
n t
he
Ox
ida
tio
n o
f F
e a
nd
Ste
el”, C
orr
osi
on S
cien
ce, 1
969,
9, p
p. 7
71.
53
P.
L.
Sur
man
. “
Th
e O
xid
ati
on
of
Iro
n a
t C
on
tro
lled
Ox
ygen
Pa
rtia
l P
ress
ure
s: I
– H
yd
rog
en/W
ate
r V
ap
ou
r”.
Corr
osi
on S
cien
ce, 1
973,
13,
pp.
113
. 54
V
. A
. N
evzo
rov,
O.
V.
Sta
rkov
and
N.
G.
Bar
anov
, “
Hig
h T
emp
era
ture
Ox
idati
on
of
Ste
els
in W
ate
r V
ap
ou
r”, Z
asc
hit
a M
eta
llo
v, 1
970,
6, p
p. 3
49.
NP
L R
epor
t M
AT
C(A
)90
Pag
e 39
of
39
55
H.
Sak
ai,
T.
Tsu
ji a
nd K
. N
aito
, “E
ffec
t of
Oxygen
Part
ial
Pre
ssu
re o
n O
xid
ati
on
of
Iro
n a
t 5
73
K”
, Journ
al
of
Nucl
ear
Sci
ence
and T
echnolo
gy,
198
4, 2
1, p
p. 8
44.
56
I. K
lein
, A
. E
. Y
aniv
and
J.
Sha
ron,
“T
he
Ox
ida
tio
n M
ech
an
ism
o
f F
e-N
i-C
o
All
oy
s”, O
xidati
on o
f M
etals
, 198
1, 1
6, p
p. 9
9.
57
F.
Arm
anet
, A
. V
ejux
and
G.
Ber
ange
r.
“H
igh
Tem
per
atu
re C
orr
osi
on
of
Pu
re
Nic
kel
, a
nd
Ni-
Cr,
Fe-
Ni-
Cr
or
Co
-Cr-
W-N
i A
lloys:
In
flu
ence
of
Wate
r V
ap
ou
r
Co
nte
nts
, in
I.
K
irm
an
et
al,
(Eds
),
Beh
avi
ou
r o
f H
igh
T
emper
atu
re
All
oys
in
Ag
gre
ssiv
e E
nvi
ron
men
ts”
, E
UR
-681
4, T
he M
etal
s S
ocie
ty, L
ondo
n, 4
23 (
1980
).
58
A.
Gal
erie
, Y
. W
oute
rs,
M.
Cai
llet
, “
Th
e K
inet
ic B
eha
vio
ur
of
Met
als
in
Wate
r
Va
po
ur
at
Hig
h T
emp
era
ture
s: C
an
G
ener
al
Ru
les
Be
Pro
po
sed
?”,
Mate
rials
Sci
ence
Fo
rum
, 200
1, V
ols.
369
-372
pp.
231
-238
. 59
D
. Abr
iou,
J. J
upil
le, S
urf
. S
ci.
Let
t., 1
999,
430
, 1-3
, L52
7.
60
S. W
arre
n et
al.
Surf
. Sci
., 19
99, 4
36, 1
-3, 1
. 61
B
.M. K
ats,
V.V
. Kut
arov
, L.M
. Kut
ovay
a, C
oll
oid
s. S
urf
. A, 1
999,
157
, 1-3
, 95.
