surfacing of 3.25% nickel steel with inconel 625 by the gas metal arc welding-pulsed arc process
TRANSCRIPT
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8/10/2019 Surfacing of 3.25% Nickel steel with Inconel 625 by the gas metal arc welding-pulsed arc process
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WELDING RESEARCH
S U P P L E M E N T T O T H E W E L D I N G J O U R N A L , J A N U A R Y , 19 78
S p o n s o r e d b y t h e A me r i c a n We l d i n g S o c i e t y a n d t h e We l d i n g R e s e a r c h C o u n c i l
i f 1)1
Surfacing of 3.25% Nickel Steel with
Inconel 625 by the Gas Metal Arc
Weld ing-Pulsed Arc Process
Inconel
625
can be surfaced onto 3.25 nickel steel with
excellent weldability, equivalent mechanical properties
and good corrosion and fatigue resistance
BY D. F. HASSON, C. ZANIS, L. APRIGLIANO AND C. FRASER
ABSTRACT. The resul ts of a metal lur
g ica l charac te r iza t ion o f I ncone l 625
we ld meta l su r faced on to 3 .25% n icke l
s teel us ing the gas metal arc weld ing
process are presented. I t was found
tha t I ncone l 625 was d i rec t ly we lda b le
on to 3.25 n ick el s teel . Ten si le p rope r
t ies were genera l ly comparab le t o
those for 3.25 n ick el s tee l , and the
most f avorab le mechan ica l p roper t ies
were ob ta in ed w i th a hea t inp u t o f
1.77 MJ/m (45 k j / in . ) .
The cor ros ion fa t igue s t reng th o f t he
sur face weld metal at 10 cycles was
found to be 10.34 MPa (15 ks i) , which
is lower than values repor ted for
mu l t ip le pass Incone l 625 we lds bu t i s
s ign i f i can t ly h igher t han the cor ros ion
fat igue st rength of the steel . Fat igue
crack growth rates for the sur face weld
meta l were found to be h igher t han
t h e w r o u g h t
lnconel-625
base metal
and the steel .
The seawater cor ros ion res is tance of
t he sur face we ld meta l was equ iva len t
to the wrought base metal at levels of
i r on up to 9%, p rov ided the mo lyb
denum concent ra t ion was g rea te r t han
8%. St ress re l ie f heat t re atm en t d i d no t
degrade cor ros ion o r f a t igue p roper
ties.
I n t r o d u c t i o n
Many mar ine app l ica t ions requ i re
bo th h igh s t reng th and cor ros ion res is
t an t mater ia ls f o r long te rm re l iab i l i t y
and per fo rmance. O f ten the s t reng th
can
best
be achieved by the use of
steels which do not possess the
required res is tance to seawater cor ro
s ion damage. A possib le mater ia ls
s o lu t i o n t o p r o v id i n g s t r u c t u r a l c o m
p o n e n t s wh i c h c o m b in e t h e a t t r i b u t e s
o f h igh s t reng th and seawater cor ro
s ion is to we ld sur face th e steel w i t h a
m e t a l l u r g i c a l l y c o m p a t i b l e c o r r o s io n
res is tan t a l loy . Among the charac te r is
t ics desira ble in such a sur fa c ing a l loy
are reasonab le s t reng th , we lda b i l i t y t o
the steel , res is tance to general and
loca l ized cor ros ion a t t ack and good
cor ros ion fa t igue p roper t ies . A cand i
da te mater ia l f o r su r fac ing wh ich has
D. F. HASSON is Assistant Professor,
Mechanical Engineering Department,
United States Naval Academy, and
C
ZANIS, L. APRIGLIANO and
C FRASER
are
with the Materials Department of the David
W. Taylor Naval Ship
Research
and Devel
opment
Center
Annapolis, Maryland.
exce l len t co r ros ion res is tance ' and
we ld a b i l i t y
2
-
1
is lncone l -625* ( IN-625) .
There are, however , several factors
wh ich shou ld be inves t iga ted p r io r t o
using IN-625 to sur face steel . Since the
m a x im u m a l l o wa b le i r o n c o n c e n t r a
t ion is 5% for
IN-625
and higher levels
may be an t ic ipa ted due to p ick -up
f rom the steel base metal , the ef fect of
i r on con ten t on the seawater cor ro
s ion res is tance of IN-625 weld metal
mus t be de te rm ined . A lso , t he fa t igue
crack growth res is tance of the IN-625
weld metal appears sensi t ive to the
microst ructure (gra in s ize and shape).
5
Thus, the cor ros ion fat igue st rength of
t he sur faced IN-625 we ld meta l shou ld
be establ ished.
Th e c o m p o s i t i o n , m e c h a n i c a l p r o p
er t ies and cor ros ion res is tance of the
sur faced we ld meta l may be a l t e red by
we ldi ng heat inp ut . I t is , the refo re, of
in te res t t o de te rm ine the l im i t ing
c h e m ic a l c o m p o s i t i o n (e.g., i r on c o n
cent ra t ion) o f IN-625 sur face we ld
meta l on the basis o f m echa n ica l and
cor ros ion p roper t ies w i th a v iew to
*lnconel is a registered trademark of the
International Nickel Company.
W E L D I N G R E S E A R C H S U P P L E M E N T I 1-s
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Table1Chemical Analyses of IN-625
Filler Metal, Base Metal, and 3.25 Nickel
Steel,
wt-%
Table2-Welding Parameters for Surfacing of IN-625 on 3.25 Nickel Steel
N i
Cr
M o
Fe
Nb & Ta
Si
Al
Ti
C
M n
IN-625
f i l ler
meta l
60.66
22.18
9.14
3.42
3.69
0.24
0.22
0.29
0.04
0.01
IN-625
base
meta l
62.00
21.41
8.64
2.73
4.15
0.30
0.24
0.27
0.03
0.15
3.25
n icke l
s teel
3.27
0.40
0.43
Bal.
0.22
-
-
0.26
0.35
using IN-625 for sur fac ing of a mar ine
steel,
such as 3.25 nickel steel.
The approach for the present s tudy
was to vary the heat input on a par t ic
u la r we ld p rocess and eva lua te t he
r e s u l t a n t c h e m ic a l c o m p o s i t i o n a n d
mechan ica l p roper t ies . The hea t inpu t
wh ich gave mechan ica l p roper t ies
comparab le o r super io r t o t he 3 .25
nickel s teel was selected for the cor ro
s ion and fat igue tests.
E x p e r i me n t a l P r o c e d u r e
Materials
The sur fac ing mater ia l was MIL-E-
21562 1.1 mm (0.045 in. ) d iameter IN-
625 f i l ler metal . The IN-625 was
sur faced onto 50.8 mm (2 in. ) th ick by
203.2 mm (8 in. ) wide by 609.6 mm (24
in.) long plates of 3.25 nickel steel.
A 25.4 mm (1 in. ) th ick hot ro l le d
and annea led p la te o f IN-625 wh ich
confo rmed to ASTM B-443
7
was used
to establ ish base metal proper t ies. The
chemical analyses of these mater ia ls
are g iven in Table 1.
Voltage
peak/
background,
V
33 34/26
33 34/26
35 38/25 28
36 38/26 28
Current,
A
200-220
200-220
190-210
180-205
Travel
speed,
mm/sec
(ipm)
6.8 (16.0)
4.7 (11.0)
3.6 (8.5)
3.0 (7.0)
Deposit ion
rate,
kg/h
(Ib/h)
22 (10)
22 (10)
24 (11)
24 (I
I)
Heat
input,
MJ/m
(kj/ in.)
0.90 23)
1.34 34)
1.77 45)
2.08 53)
Weldment Preparation
One and two layers of IN-625 were
weld sur faced onto the steel p lates in
the f la t posi t ion by the gas metal arc
we ld in g - p u l s e d a rc ( G M AW - P) p r o
cess. The hea t inpu ts and w e ld ing
parameters are presented in Table 2.
Since the 3.25% nickel s teel may
requ ire a po stw eld st ress re l ie f hea t
t rea tment , a l l su r faced p la tes were
stress relief heat t reated at 649 C (1200
F) for 4 hours (h).
Evaluation
Weldab i l i t y was es tab l ished by
means of dupl icate, 180 deg 2T s ide
bend tes t s a t room tempera tu re . Bend
tes t spec imens con fo rmed to
M I L -
STD-00481C
and were cu t norma l t o
t h e we ld in g d i r e c t i o n , a s s h o w n i n F ig .
1. The one layer sur faced spec imens
included at least 3.2 mm (0.125 in.) of
we ld meta l . Tw o layer spec imen s had
at least 6.4 m m (0.250 in.) of w e ld
metal .
A f te r ben d ing , conve x sur faces were
v isua l ly examined fo r ev idence o f
c rack ing . I n add i t ion , sec t ions f rom a l l
we ld m e n t s we r e e x a m in e d m e t a l l o -
g raph ica l ly a f t e r e lec t rochemica l e t c h
ing in a so lut io n of 12 ml H
3
PO.,, 47 ml
H,SO, and 41 ml HNO., . The chemical
compos i t ions o f a l l we ld meta ls were
dete rm ined by X- ray f luo rescence
analysis.
A l l -we ld meta l t ens i le spec imens
were removed f rom each w e l d , as
show n in F ig. 1 , and co n fo rm ed to
ASTM spec i f i ca t ion
E8
for subsize f la t
t ens i le spec imens . Spec imens were
tested at room temperature at a s t ra in
r at e o f 0 .0 03 m m /m m /m in u t e . Fo u r
Rockwell-C
hardness measurements
were a lso per fo rmed on each w e l d
ment and the values were averaged.
Up o n c o m p le t i o n o f t h e a b o v e
we ld a b i l i t y , c h e m ic a l c o m p o s i t i o n a n d
tens i le p roper t y measurements , w e l d
ments were p repared a t a se lec ted
heat inpu t f o r eva lua t ion o f seawater
c o r r o s io n a n d c o r r o s io n - f a t i g u e p r o p
er t ies of the sur faced IN-625 weld
meta l .
As i l lust rated in Fig. 1, a l l co r ro
s ion pane ls and fa t igue spec imens
we r e r e m o v e d c o m p le t e l y f r o m we ld
meta l . For com par iso n in t he c or ros ion
tes ts , wr ou gh t IN-625 base meta l spec
imens were a lso eva lua ted . The sea
water cor ros ion tes t ing may be sum
mar ized as fo l lows :
1.
General Corrosion.
T w o w e l d
metal panels and two IN-625 base
metal panels each 203.2 X 76.2 x 2.5
S T R E S S - C O R R O S I O N
SPECIMEN
I NCO NE L 625
W E L D C L A D D I N G
T E NS I LE S P E CI M E N
C O R R O S I O N - F A T I G U E
G E N E R A L A N D
C R E V I C E - C O R R O S I O N
S P E CI M E N
3 . 25 N I C K E L S T E E L
SIDE-BEND
W E L D A B I L I T Y S P E C IM E N
Fig.1Orientation of specimens removed from Inconel 625surface welds
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4 . 7 MM ( 3 / 16 ) D I A . SUPPORT R OD
_TEST P A N E L W I T H
12 . 7 MM (1/2 )
C E N T E R H O L E
22 MM
(7/8 i
D E L R I N W A S H E R
E X T E R N A L L Y T H R E A D E D 1 2 .7 M M
( 1 / 2 ) O . D . D E L R I N S L E E V E
Fig.2Multiplecre
vice corrosion test
assembly: A (left)
multiple crevice
test assembly; B
(right) grooved
Delrin washer
12.7 RADIUS
NOTE:
ALL DIMENSIONS IN
MM
THICKNESS
=
2.54
mm
Fig.
4Single-edge
notch crack growth rate specimen
Table3-Chemical Analyses of IN-625 Surface Weld Metal Surfaced onto 3.25 Nickel Steel
by the GMAW-P Process
Heat
i npu t ,
MJ/m
( k j / i n . )
0.90 (23)
1.34 (34)
1.77 (45)
2.08 (53)
0.90 (23)
1.34 (34)
1.77 (45)
2.08 (53)
I N -625 we l d
m
spec i f i ca t ion
N o .
o f
layers
1
1
1
1
2
2
2
2
etal
N i
58.74
56.78
55.30
60.57
61.72
60.97
60.77
62.53
Bal.
corr
Cr
20.97
20.60
20.17
21.25
21.32
21.10
21.52
21.50
20/23
Chem i c a l
p o s i t i o n ,
w t
M o
8.90
8.87
8.32
9.04
9.07
9.11
9.14
9.12
8 / 10
o
Fe
8.46
9.76
10.85
6.14
5.12
4.64
4.00
3.67
5.00
Max
C b
3.62
3.40
3.20
3.71
3.56
3.58
3.75
3.77
3.15/
4.15
A s -depos i t ed
th ickness ,
mm ( in . )
4.0 (5/32)
4.4 (11/64)
4.0 (5/32)
4.8 (3/16)
7.1 (9/32)
8.0 (5/16)
8.3 (21/64)
8.3 (21/64)
Fig. 3Bent-beam-type
specimen. (X0.165)
stress-corrosion
mm (8 x 3 x 0.1 in. ) were exposed for
s ix months in f lowing (0.6 m/s)
seawater.
2. Crevice Corrosion. Du p l ica te t est
panels of the weld metal and base
meta l were eva lua ted fo r c rev ice
cor ros ion res is tance us ing the mu l t ip le
c rev ice t ype con f igur a t ion s how n in
Fig. 2. Aga in tests we re pe r for me d in
f lowing seawater f o r s ix months .
3. Stress Corrosion. Du p l i c a t e b e n t -
beam type specimens, 304.8 x 76.2 X
3.2 mm (12 x 3 X 0.125 in.) were used
for s t ress-cor ros ion evaluat ion of the
sur faced we ld meta l .
Figure 3 shows the apparatus in
wh ich spec imens were loaded to a
surface stress of 379 MPa (55 ksi).
Spec imens were exposed in f lowing
seawater f o r 8 months a f t e r wh ich they
were examined for cracks or other
corrosion
damage.
4. Corrosion-Fatigue.
Fat igue char
ac te r iza t ion was per fo rmed us ing bo th
Krouse- t ype p la te spec imens to es tab
l ish an S-N curve and s ingle-edge
no tch ed (SEN) specim ens (Fig. 4) for
fa t igue c rack g rowth ra te measure
ments . Krouse- t ype spec imens were
tested in seawater at a cyc l ic f re qu en
cy of 23.3 Hz and a stress rat io R = 1
These spec imens were tes ted un t i l
f racture or unt i l the number of cyc les
exceeded
IO .
8
The SEN specimens were used to
measure the ef fect of pro longed st ress
relief t ime at 649 C (1200 F) on crack
gro wth ra te . The c rack g row th d i rec
t ion was para l le l t o t he co lumnar
dendr i t es o f t he we ld meta l . G rowth
ra tes were de te rm ined by measur ing
crack exten sion , Aa, oc cu rr in g af ter a
spec i fi c n um ber o f cyc les , AN . A l l SEN
specimens were tested in a 3.5% N a C I /
Fi.O
so lu t ion un t i l f r ac tu re .
Results and Discu ss ion
Composit ion and Microstructure
The che mic al analyses of the IN-625
sur face we ld meta ls p roduced a t f our
heat input levels for one and two layer
sur faces are g iven in Table 3. The
s p e c i f i e d l im i t i n g c h e m ic a l c o m p o s i
t ion f o r IN-625 we ld
m e t a l
is also
listed in Table 3.
T h e c h r o m i u m , m o l y b d e n u m a n d
c o lu m b iu m c o n c e n t r a t i o n i n t h e s in
g le and doub le layer sur face we ld
meta l were w i th in t he IN-625 we ld
metal speci f icat ions for a l l heat inputs.
Th e m a x im u m i r o n c o n c e n t r a t i o n o f
5%, how eve r , was exce eded in a l l
s ingle layer sur face weld metal wi th a
W E L D I N G R E S E A R C H
SUPPLEMENT I
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2nd LAYER IN-625
5 Id LAYER IN-6 25
i n LAYER IN-625
INCREASING IRON
CO NTE NT,
RELATIVE
INCREASING IRON
CONTENT,
RELATIVE
Fig.5Microprobe traces across two-layer C M A W IN-625surface
weld showing relative iron levels: A (left)scan across both
interfaces of steel surface welds;
B (right)~closeup
scan of
steel/
Inconel 625 interface
0 . 9 0 M J / m
2 3
k j / i n
1 . 3 4 MJ/m
3 4 k j / i n
1 . 7 7 MJ/m
4 5
k j / i n
2 .08 M J /m
5 3
k j / i n
^HfP^imt
F/g. 6Structureoi C M A W Inconel 625
surface weld (heatinput-1.77 Ml/m (45 kll
in.)): A (top)transverse to welding direc
tion; B
(bottom)normal
to A. X250
(reduced
50
on reproduction)
high value of 10.85% for the 1.77 kj /m
(45 kj / in . ) heat inpu t .
I t was noted that sur face welds
prepared wi th a heat input o f 2 .08
k j /
m (53
k|/in.
had the lowest i ron
content in both sing le and two layer
deposi ts. Th is fact is a t t r ibuted to the
low amperage used at th is heat input ,
and par t icu lar ly to the slow weld t rave l
speed used to generate th is heat input
(Table 2). The slow travel speed results
in the weld ing arc be ing more
comp le te l y i n con tac t w i th the mo l ten
weld puddle than was the case at
h igher speeds and lower heat inputs.
At h igher w eld t rave l speeds, the arc
contacts more base meta l and h igher
leve ls o f i ron are p icked up in the
in i t ia l layer o f weld deposi t . The i ron
content o f the second layer o f sur face
weld appears to ver i fy that the amount
o f d i l u t i on decreased as the we ld in g
travel speed was decreased and as heat
input was increased.
Examina t ion o f the above chemica l
co mp o s i t i o n , a n d a s - d e p o s i t e d
thickness data in Table 3 indicates that
ViYJ
2 INCHES 3
4 5
ihlilililihhhlrtrtiWl
f f f / d i l i l i l i i i l
Fig.7Bend test specimens from C M A W (pulsed-arc) single layer Inconel 625 overlays
two- layer IN-625 welds can be sur
faced wi th a f ina l th ickness greater
than 6.4 mm
(V A
i n. ) and w i t h a che m
ica l composi t ion in the second sur face
laye r wh ich con fo rms to IN-625 .
Elect ron microprobe scans for i ron
were pe r fo rmed on samp les wh ich
included the stee l base meta l and two
layers o f sur face weld meta l . The
results of these scans are presented in
Fig.
5. I t is obs erv ed tha t the lev el of
i ron con tent is cons tant for a l l prac
t ica l purposes through the th ickness of
the f i rst layer o f the weld meta l .
How ever, there is a very na rrow zon e
at the weld meta l -stee l in ter face in
wh ich a d ist inc t grad ient in i ron
con ten t was obse rved . The appearance
of th is narrow zone is i l lust ra ted in
Fig.
5B.
As shown in F ig . 5 , the t ransi t ion
f rom the in i t ia l layer o f weld meta l to
the second layer is marked by an
abrup t reduct ion i n i ron con ten t .
Ag a in ,
the i ron leve l is constant
through the th ickness of the second
layer o f weld meta l . I t should be noted
that s imi lar t raverses on d i f ferent
samp les f rom the same we ldmen t
revealed ident ica l t rends. There were
di f ferences in the leve l o f i ron content
be tween beads in the we ld me ta l , bu t
the i ron con ten t was constan t th rough
the th ickness of each
bead.
Typ ica l micros t ruc tu res o f the IN-
625 sur face weld meta l prepared by
the GMAW-P process are presented in
Fig. 6 . The mic ros t ruc ture t ransverse to
the we ld ing d i rec t i on cons is ts o f
co lumnar dendr i tes wh ich g row no r
mal to the weld meta l /base meta l
in ter face wi th second phase par t ic les
concen t ra ted in the i n te rde ndr i t i c
regions. I t was noted that the
co lumnar dendr i tes were , i n some
cases, con t inuo us th roug h the i n te r
face of layers 1 and 2 of the surface
we ld me ta l . Thus, there appears to be a
h igh degree of gra in d i rect iona l i ty in
the sur face microst ructure.
Figure 6B i l lustrates the surfacing
deposi t microst ructure t ransverse to
the co lumnar dendr i t i c s t ruc tu re d i s
cussed above and shows a f ine, ra ther
un i form d ispersion of severa l phase
part ic les in the weld meta l st ructure.
These part icles may be carbides r ich in
n icke l ,
c o l u m b i u m , o r m o l y b d e n u m ,
as sugges ted in the l i t era tur e. '
Examina t ion o f micros t ruc tu res
f rom the GMAW-P su r faced we ld
meta ls revealed that the dendr i te arm
spacing genera l ly increased wi th in
creasing heat input. This resulted in a
re la t ive ly coarse microst ructure in the
weld deposi ts fabr icated at the h ighest
heat input . I t should be noted that
me ta l l og raphy o f the we ld depos i t s
and of the HAZ of the base meta l d id
not show any evidence of cracking.
Weldability Testing
Al l s ide bend test specimens f rom
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Table4 Tensile and Hardi
Heat input ,
MJ/m (kj/in.)
0.90 (23)
1.34 (34)
1.77 (45)
2.08 (53)
0.90 (23)
1.34 (34)
1.77 (45)
2.08 (53)
0.90 (23)
3.25 Nickel Steel
less
Properties
Layers
1
1
1
1
2
2
2
2
3
of IN-625 C M A W Pulsed Arc )
U l t i m a t e
tens i le s t rength ,
MPa (ks i )
801 (116.2)
787 (114.1)
77 6
(112.6)
790 (114.6)
810
(117,5)
839 (121.7)
818 (118.6)
834 (120.9)
793 (115.0)
772 (112.0)
751 (108.9)
806 (116.9)
869 (126.0)
814 (118.0)
849 (123.2)
873 (126.6)
775 (112.4)
785 (113.8)
80
min
Surface Weld Meta l on
0.2%
y ie ld s t rength ,
MPa (ks i )
461 (66.9)
462 (67.0)
443 (64.2)
461 (66.9)
512 (74.3)
516 (74.9)
498 (72.2)
525 (76.2)
517 (75.0)
532 (77.2)
515 (74.7)
568 (82.4)
553 (80.2)
535 (77.6)
550 (79.7)
561 (81.4)
539 (78.2)
536 (77.8)
55 min
3.25
Nickel Steel
Elongation
in 1 in. , %
31
28
29
28
33
28
28
28
18
21
25
31
34
23
31
36
18
14
22
min
Hardness ,
R,
17
16
22
22
18
21
20
24
16
t he GMAW sur fac ing depos i t s per
f o rmed sa t is fac to r i l y , and there was no
ev idence o f c rack ing in t he we ld meta l
or HA Z as a resul t of app l ica t ion of 180
deg ben d a ro und a 2T rad ius
m a n
dre l .
Typical s ide bend test specimens
f rom the GMAW sur face we ld meta ls
are pres ente d in Fig. 7. These results
a t t es t t o t he good we ldab i l i t y o f IN-
625 to s teel . Fur ther , i t should be noted
that a l l sur face welds were st ress- re l ie f
hea t tr ea ted p r io r t o t es t ing . The ab ove
resul ts indicated that the 649 C (1200
F)
for 4 h stress relief heat t reatment
d id no t adverse ly a f f ec t we ldab i l i t y .
Tensile Properties
The tensi le proper t ies of the IN-625
sur face we ld meta ls p repared by the
GMAW-P process a re p resen ted in
Ta b le 4, a l o n g w i t h t h e m i n im u m
required tensi le proper t ies for the 3.25
nickel s teel . For the s ingle- layer sur
face welds, a l l measured IN-625 tensi le
proper t ies exceeded the tens i le p rop
er t ies speci f ied for 3.25 n ickel s teel .
The bes t combina t ion o f s t reng th and
duc t i l i t y was measured on spec imens
f rom th e s ing le - layer surfaces p repare d
at heat inpu ts of 1.77 and 2.08 M | / m
(45 and 53 k j / in . ) .
The we ld meta l s treng th p rope r t ies
measured on spec imens removed f rom
tw o layer sur faces ( inc l ud ing layers 1
and 2 ) were genera l ly h igher t han the
values measured for s ingle layers,
par t icu la r ly w i t h respec t t o t he y ie ld
s t reng th . Once aga in , t he bes t combi
na t ion o f s t reng th and duc t i l i t y was
observed in welds fabr icated at 1.77
and 2.08 MJ/m (45 and 53 k j / in . ) . I t
was noted in the tensi le data for the
two- layer spec imen prepared a t a hea t
inpu t o f 0 .90 M J / m (23 k j / i n . ) t ha t t he
tens i le e longat ion va lues d id no t meet
the m in imum requ i rement f o r 3 .25
nickel steel of 22%.
Examinat ion of the f racture sur faces
o f t hese spec imens revea led a number
o f lack o f f us ion de fec t s wh ich caused
premature tens i le f rac tu re . Th is obser
vat ion suggests that the 0.90 MJ/m (23
kj / in . ) heat input is not suf f ic ien t to
ob ta in t he requ i red degree o f f us ion
with the in i t ia l layer of IN-625. There
was some sca t te r be tween the u l t i
mate tens i le s t reng th and e longat ion
va lues measured on dup l ica te spec
imens f rom the 1.34 and 1.77 MJ/m (34
Fig.
8Typical
tensile fracture surface of
Inconel 625 surface we ld metal on 3.25
nickel steel by the GM AW (pulsed arc)
process. A (top)-
X
225;
6 (bottom)-
X2000
and 45 k j / in . ) su r face we lds .
The var ia t ion on dup l ica te spec
imens was p robab ly due to observed
sca t te red in te rd end r i t i c m ic ro poro s i t y
in t he spec imens . As shown in t he
f ractographs of Figure 8, tensi le f rac
tures of the specimens f rom the
G M A W o v e rl a ys we r e d u c t i l e i n n a t u r e
and occur red a long the dendr i t e in te r
faces.
Examinat ion of the hardness data in
Table 4 reveals that there was a good
cor re la t ion be tween the tens i le
st rength of the over lay and the Rock
wel l C hardness. I t appears that a
m in imum average hardness o f Rock
wel l C16 is indicat ive of a tensi le
st rength greater than
758
MPa (110 ksi)
in t he IN-625 sur face we ld meta l .
Corrosion-Fatigue
The resu l t s o f h igh-cyc le cor ros ion
fat igue tests on IN-625 we ld me tal
sur faced by the GMAW-P process a t a
heat inp ut of 1.77 M | / m (45 k j / in . ) are
presen ted in Fig. 9, wh ere the S-N
curves for IN-625 mult ip le pass
w e l d
ments and for 3.25 n ickel s teel tested
in seawater are a lso inc luded for
c o m p a r i s o n .
1
The test resul ts on IN -
625 sur face we ld meta l exh ib i t e d so me
scat ter , but general ly l ie below the
mul t ipass IN-625 we ld curve and
above the steel curve. The fat igue
st rength of the IN-625 sur face weld
me tal in seaw ater is 103 MP a (15 ksi).
The lower f a t igue s t reng th o f t he
sur faced IN-625 weld metal may be
due in par t t o t he d i rec t iona l i t y in t he
mic ros t ruc tu res o f t he sur faced we ld
meta l wh ich was d iscussed above .
Work by
Long'
1
indica tes that the
rate of pro pa ga t ion of a fat ig ue crack
in the IN-625 sur face weld metal is
more rap id when the c rack is mov ing
W E L D I N G R E S EA R C H SUPPLEMENT I 5-s
-
8/10/2019 Surfacing of 3.25% Nickel steel with Inconel 625 by the gas metal arc welding-pulsed arc process
6/8
-
1
1 ^v
3.25
NiSTEEL
V
SEAWATER (RCB
SPECIMENS)
( R E F E R E N C E 101
PRESENT
o - IN 625 G MAW
- IN-625 GMAW
C O N T A I N I N G
_ L
I NCONEL 625
M U L T I P L E
1
W E L D M E N T ,
PASS
SEAW ATER ( RCB
( R E F E R E N C E
S t \ o
I N V E S T I G A T I O N ^ s
C L A D
C L A D
W E L D M E T A L
W E L D M E T A L
1 / 4 W ELD FLAW S
0 /
I
SPECI MENS)
10)
~S~
I NCONEL
C L A D D I N G
1
625 W ELD
SEAW ATER
^-o
1
-
STRESS- I NTENSI TY FACTOR RANGE AK . MPA ArT
20 30 40 50 60 8 100
I I I I I I 25 000
CYCLES TO FA I LURE, N
Fig.
9High-cycle
fatigue curve for Inconel 625 surface weld m etal in seawater
para l le l t o t he dendr i t e ax is t han when
moving normal to i t . I t has a lready
been ment ioned tha t t he Krouse spec
imens were removed so tha t c rack
growth wou ld p roceed para l le l t o t he
axis o f t he long co lu mn ar de ndr i t es o f
the sur face w e l d . The mu l t ipass we ld
spec imens , on the o ther hand,
c o n
s is ted o f a much more randomly
or ien ted m ic ros t ruc tu re . The low er
fat igue proper t ies of the sur face weld
meta l compared to t he mu l t ip le pass
we lds , t here fo re , appear t o resu l t f r o m
t h e c o m b in e d e f f e c t o f
microdefects
n o r m a l l y e n c o u n t e r e d i n we ld m e t a l s
and an un favora b ly a l igned m ic ro -
st ructure.
Another f ac to r wh ich mus t be no ted
rega rding th e fa t igue resul ts in Fig. 9 is
tha t t he Krouse spec imens used here in
expose more weld metal sur face area
to test than the t ransverse weld
ro ta t ing can t i lever beam (RCB) spec
imens used to deve lop the mu l t ipass
we ldm en t curve . Thus , t he Krouse
test s a re cons id ered more conserva t ive
and shou ld be more represen ta t ive o f
t he fa t igue p roper t ies o f su r faced we ld
metal than the RCB data.
The e f f ec t s o f macroscop ic we ld
f laws , de tec tab le by bo th rad iogra ph ic
and penet ran t t es t ing , we re e xamine d
by tes t ing spec imens con ta in ing we ld
defects up to 6.4 mm (0.25 in.)
long ,
or ien ted bo th para l le l and norma l t o
the specimen axis, at stress levels of 41
MPa (6 ksi) and 103 MPa (15 ksi) in air
and seawa ter . As indi ca ted in Fig. 9,
these specimens surv ived 10
s
cyc les
wi th no de tec tab le inc rease in f law
size.
The ef fects of pro longed st ress re l ie f
hea t t r ea tment on fa t igue c rack in i t ia
t ion and p ropagat ion were a lso inves
t iga ted .
Ro t a t i n g c a n t i l e v e r - b e a m f a t i
gue spec imens were removed f rom IN-
625 base p la te t ha t had undergone a
simulated st ress- re l ie f heat t reatment
of 64 h at 649 C (1200 F), and were
tested at 276 MPa (40 ks i) an d 414 MPa
(60 ksi) in seawater. Test results were
comparab le t o h igh-cyc le f a t igue da ta
on annealed (982 C or 1800 F, 1 h,
A. C.) base metal tested in air
Fatigue-Crack Growth
Sing le edge no tch- t ype c rack p ropa
ga t ion spec imens cu t f r om sec t ions o f
a s ing le - layer sur face we ld w ere sub
jected to s t ress re l ie f heat t reatments
of 649 C (1200 F) for 4 and 64 h. These
spec imens were in tended to measure
the ef fect , i f any, of pro longed st ress-
re l ie f heat t reatment on fat igue crack
growth rates in the sur face weld
metal .
Resul ts of fat igue crack growth rate
tests on the IN-625 sur face weld metal
are presente d in Fig. 10. Also s ho wn in
Fig. 10 are resul ts of ea r l ier wo rk on
wrought IN-625 p la te and 3 .25 n icke l
steel.
5
It is no ted that the crack gr ow th
rates of the c lad weld metal are h igher
than ra tes f o r bo th t he wr ou gh t IN-625
and the 3.25 n ickel s teel .
The h igher g rowth ra tes in t he IN-
625 sur face we ld meta ls compared to
the wrought p la te a re a t t r ibu ted
pr imar i l y t o t he m ic ros t ruc tu ra l d i f f e r
ences be tween the two p roduc t f o rms .
The weld metals are character ized by
a n e lo n g a t e d d e n d r i t i c s t ru c t u r e w h i c h
was essent ia l ly paral le l to the crack
growth d i rec t ion . I n con t ras t , t he
wro ugh t mater ia ls a re charac te r ized by
an equ iaxed g ra in s t ruc tu re .
The e f f ec t s o f o r ien ta t ion and g ra in
s t ruc tu re on c rack g rowth ra te were
note d e lsewhere. ' Th e di f feren ces in
c rack g rowth ra tes be tween the sur
face weld metals heat t reated for 4 h
10 15 20 25 30 40 50 60 80 100
STRESS- I NTENSI TY FACTOR RANGE. AK . KS I / i N
Fig.
70
Crackgrowth rate, da/dN, vs. stress-
intensity range,
AK,
for IN-625 surface weld
metal
and 64 h at 649 C (1200 F) are not
cons idered s ign i f i can t . Fur ther , t he
relat ive posi t ion of the curves is in ter
preted to mean that pro longed st ress
rel ief heat t reatment does not a l ter
cor ros ion fat igue crack growth rates of
the c lad IN-625 sur face weld metal .
General Corrosion Tests
The chem ica l comp os i t io ns o f the
wrought IN-625 base meta l and o f t he
a l l -we ld meta l genera l co r ros ion tes t
panels are sh ow n in Tables 1 and 5,
respec t ive ly . The compos i t ion o f t he
wr o u g h t b a s e - a n d we ld - m e t a l s a m
p les co n fo rm ed to t he IN-625 base-
and we ld -m eta l spec i f i ca t ions . Fur
t her , t he com po s i t io n measured o n
both sur faces o f t he we ld -meta l pane ls
ind ica ted tha t t here was no s ign i f i can t
chemica l va r ia t ion th rough the spec
imen th ickness .
The genera l co r ros ion o f bo th t he
IN-625 base metal s tandards and the
sur face we ld m eta l , as de te rm ine d by
weight loss (Table 7), was v ir tual ly n i l
a f ter 6 months in seawater . Visual
examinat ion d id not reveal any s igns of
genera l co r ros ion .
As t h e c h e m ic a l c o m p o s i t i o n o f
these panels was s imi lar to the IN-625
6-s
I
JANUARY 1978
-
8/10/2019 Surfacing of 3.25% Nickel steel with Inconel 625 by the gas metal arc welding-pulsed arc process
7/8
Table
5-Partial
Chemical Analysis of IN-625 Surface Weld Metal Seawater Corrosion Specimens
Composit ion, wt-%
Specimen type
General corro
sion
Side of surfacing analyzed
Free surface of weld
Side of weld closest to base metal
Cr
21.63
21.38
M o
9.37
8.53
Fe
4.42
4.64
C b
3.62
3.69
Crev ice cor ro- F ree sur face o f we ld
s ion S ide o f we ld c loses t t o base me ta l
St ress cor ros ion Free surface of w el d
I N -625 W e l d M e t a l S pec i f i c a t ion
20.70
20.61
20.95
20 / 23
9.28
9.34
9.28
8 / 10
8.60
9.44
5.80
5.00 Max
3.51
3.54
3.43
Cb and Ta
3.15/4.15
Table
6-Results
of General and Crevice Corrosion Tests on IN-625 Surface Weld Metal
and Base Metal
G ene ra l
c o r ros i on
Crev ice
c o r ros i on
S pec i m en
type
Sur face
w e l d
Base
meta l
Sur face
w e l d
Base
meta l
O r i g i na l
293.05
293.87
270.20
415.15
412.36
262.15
246.81
415.95
419.80
Wei gh t , g ram s
Final
293.02
293.80
270.18
415.12
412.32
261.62
246.68
415.92
419.80
Loss
0.03
0.07
0.02
0.03
0.04
0.53
0.13
0.03
0.00
mpy
Ni l
N i l
Ni l
N i l
N i l
0.2
Ni l
Ni l
0.0
Co r ros i on
rate
fiM/Year
Ni l
0.5
Ni l
Ni l
Ni l
3.9
1.0
Ni l
0.0
base plate, the resul ts indicate that the
s t ruc tu re o f t he sur face and we ld
metal and the st ress- re l ie f heat t reat
ment d id no t have a de t r im enta l e f f ec t
on the exce l len t genera l co r ros ion
resis tance inherent to the IN-625 base
meta l compos i t ion . The resu l t s o f
cor ros ion tes t s on pane ls w i th h igher
i ron contents are d iscussed in the
f o l l o w in g s e c t i o n s .
Crevice Corrosion.
The i ron and
m o ly b d e n u m c o n t e n t s o f t h e c r e v i c e
c o r r o s io n p a n e l s we r e b o t h a p p r o x i
mate ly 9% (Tab le 5 ) . V isua l examina
t ion of two test panels revealed that ,
ou t of 40 po ten t ia l p i t s i tes, not on e p i t
wa s p r o d u c e d .
This resul t i l lust rates the excel lent
crev ice-cor ros ion res is tance of the sur
f ace we ld m eta l . The w e ig h t loss o f t he
sur face we ld -meta l samples was neg l i
g ib le ,
as indicated in Table 6. The
crevice-cor ros ion res is tance of these
s u r fa c e we ld - m e t a l p a n e l s wa s e q u i v a
lent to the base metal panels which
had no p i t s and neg l ig ib le we igh t loss .
Th is was expec ted s ince the mo lyb
d e n u m c o n t e n t , wh i c h c o n t r o l s c r e
v ice-cor ros ion res is tance , was ma in
ta ined above 8% , even w i t h a 9% i ron
c o n t e n t .
The c rev ice-cor ros ion tes t a lso p ro
v ides an indicat ion of the res is tance of
the sur face weld metal to general
cor ros ion at the 9% Fe level . Since the
c rev ice-cor ros ion tes t pane ls showed
no s igns of crev ice at tack or general
cor ros ion and s ince the weight loss
f rom these pane ls was neg l ig ib le , t he
general cor ros ion res is tance of sur face
we ld metal at the 9% Fe and 8% M o
leve ls shou ld be exce l len t .
Stress-Corrosion Cracking. Af ter 8
months of exposure to seawater at 90%
of y ie ld s t reng th , t he ben t -b ea m spec
imens o f
clad-weld
meta l d id no t
show s igns o f c rack ing o r cor ros ion .
These specimens had an i ron level of
5.8% and were stress relieved at 649 C
(1200 F) for 4 and 64 h. Thus, we ld c lad
IN-625 with th is i ron level and st ress-
re l ie f cond i t ion does no t have an
apparent s t ress-cor ros ion cracking
p r o b le m .
A p p l i c a t i o n C o n s i d e r a t i o n s
A l t h o u g h t h e r es u lt s o f w e ld a b i l i t y ,
mechan ica l p roper t y and seawater
cor ros ion tes t s repor ted here in i n d i
c a te t h e g o o d c o m p a t a b i l i t y b e t w e e n
sur faced ' IN-625 we ld meta l a nd the
s tee l ,
t here a re cer ta in po in t s w h i ch
must be assessed pr ior to sur fac ing:
1. IN-625 is more noble than 3.25
n icke l s tee l , and the sur faced we ld
meta l shou ld represen t an impenet ra
ble bar r ier to prevent local ruptures in
the IN-625 and undes i rab le ga lvan ic
cor ros ion . I nspec t ion requ i rements
shou ld ensure tha t a l l accep tab le f laws
are ben ign and wi l l no t p ropagate .
2. The ap p l ica t io n o f aus ten i t i c
sta in less steel hardfac ing has been
repor ted to resu l t in un favorab le
tensi le res idual s t resses in the weld
deposi t , even af ter thermal s t ress
relief.
12
The re ten t ion o f t ens i le res id
ua ls in t he we ld meta l were a t t r ibu ted
to d i f ferences in the coef f ic ient of
t herma l expans ion be tween the s tee l
and the sur faced we ld meta l . Thus ,
coo l ing f rom the s t ress re l ie f t empera
ture can restore tensi le res iduals in the
sur faced we ld meta l wh ich may be
d e t r im e n t a l t o f a t i g u e p e r f o r m a n c e .
Sho uld such a s i tu at ion ar ise in the I N -
625/3 .25 n icke l s tee l sys tem, cons ider
a t ion o f co ld ro l l ing o r peen ing o f t he
sur face s tee l t o m in im ize o r e l im ina te
the tensi le res idual s t resses may be
necessary.
13
C o n c l u s i o n s
1. IN-625 is sat is fac tor i ly w eld ab le
to 3.25 n icke l s tee l us ing the G M A W -P
process. Stress relief heat t reatment at
649 C (1200 F) d id not adversely af fect
we ld a b i l i t y .
2. The tensi le prop er t ies of IN-625
sur face we ld meta l a re genera l ly com
parab le w i th t he requ i rements o f 3 .25
n icke l s tee l . The mos t f avora b le m e
chan ica l p roper t ies were ob ta ined
w it h a heat inpu t of 1.77 M J/ m (45
k j / in . ) .
3. The seawa ter cor ro s io n res is tance
of IN-625 sur face weld metal is equiv
a lent to that of wrought base metal at
i r on con ten ts o f up to 9%, p rov ided the
mo lybd en um c on te n t i s g rea te r t han
8%. For weld metals in the above
c o m p o s i t i o n l im i t s t h e c r e v i c e c o r r o
s ion res is tance was excel lent to good.
No suscept ib i l i t y to s t ress cor ros ion or
general cor ros ion was noted. St ress
relief heat t reatment at 649 C (1200 F)
for t imes up to 64 hours d id not a l ter
cor ros ion behav io r o f t he we ld meta l .
4.
t he seawater cor ros io n fa t igue
s t reng th o f c lad IN-625 we ld meta ls
was 103 MPa (15 ksi) at 10 cycles. This
va lue is lower t han IN-625 mu l t ip le
pass we ldm en ts , bu t i s s ign i f i can t ly
higher than that of 3.25 n ickel s teel .
5. The fat igue crack growth rate of
sur face IN-625 weld metal is h igher
than that of the wrought base metal
W E L D I N G R E SE A R C H S U P P L E M E N T I
7-s
-
8/10/2019 Surfacing of 3.25% Nickel steel with Inconel 625 by the gas metal arc welding-pulsed arc process
8/8
and 3.25 n ickel s teel when crack
gro wth p roc eeds in a d i re c t ion para l le l
t o t he h igh ly o r ien ted dendr i t i c s t ruc
tu re .
The inc reased c rack g rowth ra te
paral le l to the dendr i tes is bel ieved to
con t r ibu te t o t he lower f a t igue
s t reng th o f t he sur face we ld meta l
compared to mu l t ip le pass sur face
we ld m e n t s o r t h e w r o u g h t b a s e
plate.
References
1. Fink, F. W ., and Boy d, W . K., Th e
Corrosion of Metals in Marine Environ
me nts, AD 712 585,
NTIS,
Springfield, VA,
1970.
2. Gilliland, R.
C,
and Slaughter, G. M.,
The Welding of New Solut ion-Strength
ened Nickel-Base Alloys,
Welding lournal,
45 (7), July 1966, Research
Suppl.,
pp .
314-s
to 320-s.
3. Conaway, H. R.. and Mesick, |. H., A
Report on New Matrix-Stiffened Nickel-
Chromium Welding Products,
Welding
lournal,
49 (1), Jan. 1970, Research
Suppl.,
pp .27-s to 32-s.
4. Anon ., Incon el Alloy 625, Hun t ing-
ton Alloy Products Division, The Interna
t ional Nickel Company, Inc., Hunt ington,
WV, 1970.
5. Lo ng, T. A., Jr., Co mp aris on of F atigue
Crack Propagation in Inconel 625 and 3.25
Nicke l Steel, Masters Thesis, M.I.T., June
1972.
6. Electrod e and RodsW elding, Bare,
Nickel Alloy , Mi l Spec MIL-E-21562D, 25
May 1972.
7.
Nicke l -Chromium-Molybdenum-Co-
lumbium Alloy Plate, Sheet and Strip,
ASTM B433-66, 1974.
8. Mec han ical Tests for We lded Joints,
Military Standard, MIL-STD-00418C, 15 June
1972.
9. Tension Testing of Metallic Materials,
ASTM E-8, Phila., PA, 1974.
10. Czyryca, E., Un pub lished data,
DTNSRDC, Annapolis.
11. Kruger, J., and Am bros e, J. R., Th e
Role of Passive Film Growth Kinetics and
Properties in Stress Corrosion and Crevice
Corrosion Sus ceptibility, National Bureau
of Standards, IR76-1170, Nov. 1976.
12. Babaev, A. N., and Vainerman, A. E.,
The Residual Stresses in Hardfaced
Shafts,
Avt. Svarka,
No. 2, 1976, pp. 35-37.
13. Shoak, L.
L
Jr., and Long, C. L,
Surface Cold Rolling of Marine Propeller
Shafting, SNAME 1957, pp . 682-702.
WRC Bulletin 224
February 1977
Interpretive Report on Underwater Welding
by Chan-L iang Tsa i and Ko ich i Masubuch i
The fundamentals of underwater weld ing presented in th is repor t were based on the three-year research
program en t i t led
Fundamental Research on Underwater Welding
( conduc ted f rom Ju ly 1971 to June 1974
at
M.I.T.
for the Nat ional Sea Grant Of f ice). In th is repor t , techniques of improved underwater weld ing
processes recent ly conducted, both in th is count ry and abroad, are d iscussed. There are cur rent ly two
approac hes to the imp rov em en t of qua l i ty in unde rwate r welds. One is the develop men t of an im proved
(coa ted) e lec t rode to meet t he requ i rement f o r we ld ing underwater in wet cond i t ions . The o ther is t he
el iminat ion of the wet condi t ions around the arc zone v ia d irect shie ld ing.
Publ icat ion of the repor t was sponsored by the Interpretive'Reports Commi t tee o f t he Weld ing Research
Counci l .
The pr ice of WRC
Bulletin 224
is $8.50 per copy. Orders should be sent wi th payment to the Welding
Research Counci l . Uni ted Engineer ing Center . 345 East 47th St reet . New York. NY 10017.
WRC Bulletin 223
January 1977
Hot Wire Weld ing and Sur fac ing Techniques
by A. F. Manz
This WRC Bul le t in is d iv ided in to two par ts . The f i rs t par t prese nts a non -ma the ma t ical d escr ip t ion of the
Hot Wire processes and their general chara cter is t ic s. The second par t prese nts a genera l ized in-dep th
mathemat ica l t r ea tment o f e lec t rode me l t r a te phenomena. I n add i t ion to descr ib ing Hot Wi re e lec t rode
mel t ing , Par t I I a lso p resen ts cons iderab le in fo rmat ion concern ing the genera l case o f l-R heat ing of any
moving e lect rode. Examples are g iven to demonst rate the ut i l i t y of the der ived equat ions in predic t ing the
mel t ra tes, t emp era tu re d is t r ibu t ion a nd vo l t age d rops o f mov ing e lec t rodes . Speci fi c examples co ncern in g
Hot Wires are inc luded.
Publ icat ion of th is repor t was sponsored by the Interpret ive Repor ts Commit tee of the Welding Research
Counci l .
The pr ice of WRC
Bulletin 223
is $7 .50 per copy . Orders shou ld be sen t w i t h payment t o t he Weld ing
Research Counci l , Uni ted Engineer ing Center , 345 East 47th St reet , New York. NY 10017.