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GTA Weldabi l i ty Studies on High
Manganese Stainless Steel
Progress is reported in isolating some of the factors
related to variabilities in we lding beha vior
BY W. S . B E N N E T T A N D G . S . M I L L S
A B S T R A C T . G T A w e l d a b i l i t y s t u d i e s
have been conducted on a re la t i ve ly
new aus ten i t i c s ta in less s tee l o f nom
i n al co m p o s i t i o n 2 1 C r - 6 N i - 9 M n - 0 . 3 N .
The a l loy i s cu r re n t l y m ad e by th ree
p r o ce sse s ; co n ve n t i o n a l a i r m e l t i n g ,
vacuum a rc reme l t ing (VAR) , and
electroslag r e f i n i n g ( E S R ) . E a ch
p r o ce ss p r o d u ce s m a t e r i a l o f so m e
wha t d i f fe ren t we ldab i l i t y .
Po ros i t y in a i rme l ted ma te r ia l i s
re la ted to ox ide inc lus ion leve l , and
n i t rogen con ten t wh i le VAR and ESR
poros i ty leve ls a re re la ted to n i t rogen
on ly.
S u r f a ce r o u gh n e ss a n d a r c s t a b i l
i ty a re s t rong ly in f luen ced by n i t ro
gen in a l l th ree types o f stee l . ESR
mate r ia l has p roduced much lowe r
dep th to w id th ra t ios (D /W ) than the
o the r two . The caus e of the poo r D /W
is appa ren t l y re la ted to the am oun t o f
a l u m i n u m p i cke d u p d u r i n g t h e r e -
m e l t i n g p r o c e s s . T h e a l u m i n u m
a p p e a r s t o i n te r a c t w i t h m a n g a n e se
t o p r o d u ce i n c r e a se d m a n ga n e se i n
the arc.
I n t r o d u c t i o n
High manganese s ta in less s tee l i s a
r e l a t i ve l y n ew a u s t e n i t i c s t a i n l e ss
stee l w i th a nomina l y ie ld st rength a t
room tem pera tu re in the annea led
cond i t ion o f 65 ,000 ps i (44 .8 MPa) .
The a l loy has exce l len t co r ros ion
res is tance , equa l to o r exceed ing tha t
The authors are associated with Dow
Chemical U.S.A., Rocky Flats Division,
Golden, Colorado.
Paper was selected as alternate for the
55th AWS Annual M eeting held at
Houston, T exas, during May
6-10
1974.
o f t ype 304 in most env i ronmen ts .
Fu r the r , the aus ten i te i s ex t reme ly
stab le making the a l loy very usefu l a t
c r yo ge n i c t e m p e r a t u r e s . T h i s d e s i r
a b l e co m b i n a t i o n o f p r o p e r t i e s h a s
resu l ted in increasing use o f the a l loy,
especia l ly in the a i rcra f t and nuclear
indus t r ies .
The chemistry l imi ts fo r the a l loy
a re shown in Tab le 1 . Cons ide rab le
so l id so lu t ion s t rengthen ing resu l ts
f rom the h igh n i t rogen con ten t . The
h i gh ch r o m i u m co n t e n t p r o d u ce s t h e
exce l len t co r ros ion res is tance and the
m a n ga n e se a n d n i t r o ge n p r o d u ce t h e
very stab le austen i te o f th is a l loy.
The a l loy i s p roduced by th ree dif
f e r e n t m e l t i n g p r a c t i c e s , c o n v e n
t iona l a i rme l t , vacuum a rc remelt
(VAR) , e lec t ros lag re f ined (ESR) .
E a ch m e l t i n g p r o ce ss p r o d u ce s m a t e
r ia l w i th som ewh a t d i f fe ren t im pu r i t y
chemis t r ies and d i f fe ren t inc lus ion
leve ls . These chem is t ry va r ia t ions
p l u s t h e h igh va p o r p r e ssu r e co m p o
nen ts o f the a l loy cou ld p roduce un
usua l and poss ib ly va r iab le we ld ing
behav io r .
Ea r l y expe r imen ts d id indeed show
qu i te a va r ia t ion in we ld in g behav io r
f rom one lo t o f mater ia l to another.
S o m e o f t h e co m p o n e n t s f a b r i ca t e d
f rom th is a l loy requ i re ex t reme ly p re
c i se a n d r e p r o d u c i b l e w e l d ge o m
e t r ies and low po ros i t y leve ls . The
var ia t ions seen f rom lo t to lo t fa r ex
ceeded the to le rances on some o f
these i tems. Because o f these p rob
lems a com pre hen s iv e s tudy o f the
GTA we ldab i l i t y o f th i s a l loy was un
d e r t a ke n . S e ve r a l a sp e c t s o f t h e
we ldab i l i t y have been found to be
somewha t un ique and a re repo r ted
here .
P o ro s i ty , S u r f a c e R o u g h n e s s
a n d A r c S t a b i l i t y
Ear ly a t temp ts to GTA we ld h igh
m a n ga n e se s t a i n l e ss s t e e l (HMSS)
p roduced we lds w i th la rge va r ia t ions
in po ros i t y , su r face roughness , and
a rc s tab i l i t y . Work has con t inued in an
ef fo r t to ident i fy bo th the cause and
the ex ten t o f these va r ia t ions .
Experimental P rocedures
GTA we lds have been made on a
num ber o f d i f fe ren t geom e t r ie s us ing
many d i f fe ren t cond i t i ons . Howeve r ,
f o r co m p a r i so n p u r p o se s , a u t o
ge n o u s w e l d s o n Vh in . (38 .1 mm ) or
2 in . (50 .8 mm ) d iam ba r s tock have
b e e n m a d e u s i n g t h e c o n d i t i o n s
shown in Tab le 2 .
A f te r we ld ing , the cen te rs o f the
ba rs we re bo r ed ou t leav ing a V* in.
(6.35 m m ) t h i ck wa l l . T h e cyc l i n d e r s
we re then cu t pe rpend icu la r to the
we lds and rad iographed to revea l the
ex ten t o f po ros i t y . The rad iographs
were judg ed fo r seve r i t y of po ros i t y
on a sca le o f 1 to 5 . Weld s f ree o f
de tec tab le po ros i t y (de tec tab i l i t y l i m
i ts 0 .010 in . (0 .254 mm ) d iam ) we re
ra ted as 1. We ld s w i th 5 o r mo re vo id s
per inch o f w e l d , grea ter than 0 .025 in .
(0 .635 mm) d iam we re ra ted as 5 . The
o the r ra t ings we re even ly spaced in
b e t w e e n .
The same we lds we re ra ted
fo r su r fac e roug hne ss on a sca le o f 1
to 5 w i th 1 be ing the smoo thes t s u r
face. We lds w i th ra t ings o f 1 , 3 , an d 5
are sho wn in F ig. 1 .
Du r ing GTA we ld ing on ce r ta in lo ts
o f HMSS, much e r ra t i c f l a sh ing and
some expu ls ion o f mo l ten ma te r ia l
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Table 1 — Chemis try L imi ts High
Mn
Sta in less S tee l
Element
Chromium
Nickel
Manganese
Silicon
Nitrogen
Phosphorous
Carbon
Sulfur
wt%
18.00-21.00
5.50- 7.50
8.0 -10.0
1.00 Max.
0.15- 0.40
0.060
Max.
0.040
Max.
0.030
Max.
'..
T a b l e 2 — S t a n d a r d W e l d i n g
Conditions
Fig. 1 — Extent of surface roughness variations with respective ratings
Weld current
Electrode type
Electrode gap
Torch gas
Welding speed
200A(dcsp)
EWTh-2 - 3/32 in.
diam
0.060
in.
20
cfh Ar
5 ipm
f rom the weld pool occurred. When
other lots of ma terial were
welded,
the
arc was very stable with no flashing or
expulsion. This f lashing and expul
sion is referred to here as arc insta
bility. The arc stability was rated as
good (G), fair (F), or poor (P) based
solely on the judgment of the oper
ator. In welds showing high instabil
i ty, a deposit slowly for me d on the tip
of the electrode. In some cases this
deposit grew to rather large propor
tions. Figure 2 shows some of the
more extreme deposits encountered.
These deposits occurred after ap
proximately 28 linear in. (711 mm) of
weld at arc currents of 150 A. The
tendency for deposit formation was
also rated as good, fair, or poor.
Supplementary in format ion has
also been obtained on both auto
genous and fi l ler metal addition w elds
over a wide variety of conditions. Th is
information wil l be discussed where
appropriate in the fol lowing sections.
Results and Discussion
The results of porosity, surface
roughness and arc stabi l i ty measure
ments are shown in Table 3. Several
items stand out in reviewing Table 3.
First, any one measure of weldability
is a good indicator of the other three.
Second, airmelt
material produces
consistently poor results. Third, in the
remelted
heats, poor weldability is
associated with high nitrogen con
tent. Fourth, the electrode bui ldup oc
curs when the other instabi l i t ies are
significant.
The arc instabi l i t ies appear much
like momentary short-circuit ing of the
electrode to the weld pool; violent
f lashing,
expulsion of metal and often
a loud popping sound. However ,
there is no pickup of tungsten inclu
sions in the weld metal and apparent-
Fig. 3 — Backscattered electron
micro-
graph of electrode buildup.
X100
reduced
38%
Fig. 2 — Buildup on 3/32 diam electrodes
T a b l e 3 —
Hea t
no.
81143
81698
81942
1X0555
8 2 2 8 7
( a )
82289
85598
6711
6818
7012 -1
692394
6 8 0 6 9 3
< a )
Welds mac
034037 <
a
>
039038
(a)
C h e m i s t r y
Mel t
type
VAR
ESR
Air
a n d W e l d a b i l i ty T e s t R e s u l t s o f G e n e r a l H e a t s of H M S S
N
c o n t e n t ,
w t %
0.30
0.22
0.28
0.40
0.25
0.22
0.28
0.34
0.39
0.20
0.38
0.29
le w i th adde d f i l l e r me ta l
Ai r 0 .36
0.38
O
c o n t e n t ,
ppm
75
55
3 0 - 1 3 5
30
30
175
260
320
Por
os i ty
ra t ing
1
1
1
5
1
1
1
2-3
2-3
1
5
4
4
5
R o u g h
ness
ra t ing
2
2
2
5
1
1
1
2
3-4
1
5
4
Arc
s t a
bi l i ty
G
G
G
P
G
G
G
F
P
G
P
P
Elec
t r o d e
bu i l dup
G
G
G
F
G
G
G
F
P
G
F
F
6818W
(a)
ESR
0.38
30
(a) Measu rements are from specific hardware weldments not standard test bars.
Tab le 4 — Ni trogen Loss Dur ing W e ld ing, wt %
Hea t
no.
1X0555
81143
6711
6818
82289
Me l t
type
VAR
V A R
ESR
ESR
ESR
N c o n t e n t
base me ta l
0.40
0.30
0.34
0.39
0.22
N c o n t e n t
we ld me ta l
0.35
0.26
0.25
0.26
0.20
Net loss
of n i t rogen
0.05
0.04
0.09
0.13
0.02
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
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' ; . - . ; •• , ' . : ' . ; . • ' • > • ' • •
Fig. 4 — Typical inclusion level in an
airmelt
steel. X100, reduced
27%
Fig. 5 — Typ ical inclusion level in an ESR steel. X100, reduce d
27%
Fig. 6 — Fine dispersion of inclusions viewed under differential in-
terference contrast lighting. X440, reduced 27%
Fig. Typical fusion zone shapes
for a
low D/W and a high D/W
steel. X2, reduced 27%
ly no actua l contact o f the we ld meta l
a n d t h e e l e c t r o d e . T h e e l e c t r o d e
bu i ldup has been ana lyzed by m ic ro -
p r o b e .
F igu re 3 i s a b ack sca t te red
e l e c t r o n m i c r o g r a p h of a t yp i c a l
r e g i o n o f t h i s d e p o s i t . T h e l i gh t
co lo re d phas e i s tungs ten and the
dar k m atr ix is a mi xtu re o f Fe , Cr, an d
N i w i th a t race o f S i . The me d iu m
co l o r e d r e g i o n su r r o u n d i n g t h e t u n g
s ten pa r t i c les i s a m ix tu re o f these two
phases.
An add i t i ona l aspect o f we ldab i l i t y
is tha t a second pass made over a
w e l d w h i ch p r e v i o u s l y sh o w e d h i gh
instab i l i ty is stab le and the surface is
s m o o t h .
Tab le 4 g ives n i t rogen loss
du r ing we ld ing fo r seve ra l hea ts .
A l though there is n i t rogen loss in a l l
cases, the losses are h igher in the
h igh n i t rogen hea ts .
These obse rva t ions suggest tha t a
la rge quant i ty o f n i t rogen is leaving
the we ld
p o o l .
Th is vapo r ca r r ies f i ne
d rop le ts o f mo l ten s tee l to the e lec
t rode c rea t ing the e lec t rode depos i t .
Th is d rop le t l aden gas s t ream may ac t
as a low res is tance cu r ren t pa th g iv
i n g t h e a p p e a r a n ce o f a m o m e n t a r y
short c i rcu i t . The arc instab i l i ty and
depos i t occu r on ly in the h igh n i t ro
gen hea ts , n i t rogen >0 .3 w t%, and a re
mu ch wo rse in those w i th n i t rog en
> 0 . 3 5 w t % .
Brooks (Ref . 1 ) has stud ied surface
cond i t ion and expu ls ion o f e lec t ron
beam we lds ve rsus n i t rogen con ten t
in HMSS and f inds poo r su r face c o n
d i t ion and expu ls ion a re assoc ia ted
w i th h igh n i t rogen leve ls . He a t t r ib
u tes th is behav io r to dec om pos i t i on o f
ch romium n i t r i de inc lus ions . A l l o f h i s
samp les we re a t the ex t remes, bo th
h igh and low , o f the n i t rogen con ten t
fo r th is a l loy.
W e h av e e x a m i n e d t h e m i c r o -
s t ruc tu re o f a number o f hea ts o f
HMSS to de te rm ine the re la t ionsh ip
be tween inc lus ion leve ls and GTA
we ldab i l i t y . A typ ica l i nc lus ion leve l
fo r an a i rm el t h eat is sho wn in F ig. 4 ,
wh i le F ig . 5 show s a typ ica l i nc lus ion
leve l in an ESR heat . The a i rmel t heat
con ta ins 175 ppm oxygen wh i le the
ESR hea t con ta ins 30 ppm oxygen .
M i c r o p r o b e a n a l ys i s ha s sh o w n t h e se
inclusions to be o f th ree types; (a ) en
r iched in Mn and S, (b ) enr iched in
M n ,
A l ,
and S i , and (c) enr iched in Al
on ly . The las t two types a re assumed
to be ox ides and the re i s gene ra l
agreemen t be tween inc lus ion con ten t
and oxygen leve l .
In heats w i th h igh n i t rogen c o n
ten t , a d i f fe ren t t ype o f i nc lus ion , a
f ine d ispe rs ion o f sma l l pa r t i c les , oc
c u r s , as is shown in F ig. 6 . We have
been unab le to iden t i f y these pa r t i c les
due to the i r smal l s ize , bu t Brooks
(Ref. 1 ) has ident i f ied s imi la r part ic les
as ch rom ium n i t r i des . Fu r the r , we
have seen them on ly in hea ts w i th
n i t rogen contents o f 0 .39 wt% or
h igher.
At these h igh n i t rogen leve ls, the
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n i t r i de pa r t i c l es apparen t l y de
compose, relasing free nitrogen. The
porosity could be caused by nitrogen
entrapped in the l iquid or by nitrogen
be ing expe l l ed a t so l i d i f i ca t i on .
However, porosity is quite high in the
airmelt material even when nitrogen is
as low as 0.29 wt%. Further, airmelt
f i l ler metal also produces high por
osity welds (see Table 3). In airmelt
material the oxide inclusions may
break down, releasing oxygen and
adding to the porosity content. In the
remelted material porosity level cor
relates very well with nitrogen level
and porosity is virtual ly n onexistent
when nitrogen is below 0.30 wt%. The
extreme surface roughness of the
high nitrogen material is apparently
caused by agitation of the weld pool
as the nitrogen leaves the surface.
When a second pass is made over a
weld, the nitrogen level is lower, the
nitrogen evolved is much less, and the
weld surface is smooth and quiet.
D e p t h t o W i d t h
R a t i o V a r i a t i o n s
Another interesting aspect of GTA
welding of this alloy has been a large
variation in depth of penetration and
depth to width ratio (D/W) in auto
genous welds. Figure 7 shows the
cross section of welds made at the
cond itions de scribed in Table 2 in two
different heats. Several investigators
(Refs.
2-4) have reported similar var i
ations in fusion zone geometry. Gen
era l l y these inves t igat ions have
related change in geometry with a
change in impurity chemistry, but
have not resulted in a clear-cut ex
planation for the variations. We have
run a numbe r of experiments to t ry to
find a cause for such behavior.
E x p e r i m e n t a l P r o c e d u r e s
Autogenous GTA welds have been
made on sol id bars as described
before, under the conditions of Table
2. In addition, arc lengths have been
varied from 0.040 to 0.100 in. (1.01 to
2.54 mm), welding speeds from 5 to
20 ipm (127 to 508 mm/min) and
torch gas mixtures of 25, 50, and 75%
He (balance Ar) have been used.
These welds were then sectioned and
the depth and width measured.
Several types of chemical
anal
yses have been used to determ ine the
chemical composition of each heat.
The major metal l ic al loying elements
have been analyzed using x-ray f lu
orescence. Oxygen and nitrogen have
been analyzed by inert gas fusion.
Metal l ic impurit ies have been ana
lyzed by emission spectroscopy and
spark source mass spectroscopy.
Aluminum content has also been
measured by atomic absorpt ion spe c
troscopy.
Spectral analysis of welding arcs
was performed in two ways. A GTA
welding torch was mou nted ins ide the
arc chamber of a standard 3 meter
analytical spectrograph and arc spec
t ra were reco rded us i ng pho to
graphic plates. This technique ana
lyzed l ight from the entire arc. To
analyze light from a specific region of
the arc a monochrometer was set up
with imaging optics at the inlet slit to
focus l ight from a specif ic region into
the sl i t. The resulting spectra were
then recorded photographical ly at the
exit.
R e s u l t s a n d D i s c u s s i o n
Table 5 gives D/W for welds made
per conditions of Table 2. The extent
of the variations is clearly shown in
this table. Several surface prepara
tions (as received, freshly machined,
degreased with acetone, etched with
inhibited HN0
3
) have been used on an
ESR heat and a VAR heat with no
change in response. Weld samples
have been taken f rom d i f fe rent
regions within a bar or plate and again
the results are the same. At low
welding currents (
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m i n u m .
No o the r im pu r i t y o r a l loy ing
e lemen ts show any cons is ten t re la
t i o n sh i p t o D / W . T h e a l u m i n u m c o n
ten ts and D/W's are given in Tab le 7 .
T h e se a l u m i n u m va l u e s a r e m e a
su r e d b y a t o m i c a b so r p t i o n sp e c
t roscopy and a re the to ta l o f so lub le
p l u s i n so l u b l e a l u m i n u m . T h e va r i o u s
hea ts fa l l i n to two groups; those w i th
D /W's c lus te red a round 0 .5 and those
c lus te red a round 0 .25 . Fu r the r , a l l the
low D /W hea ts a re ESR p roces sed .
Hea t 6711 has a h ighe r D /W bu t was
remelted by a s l igh t ly d i f fe ren t ESR
m e t h o d w h i ch m i n i m i ze s a l u m i n u m
p ick up and it does ind eed have a
lowe r a lum inum con ten t . The f lux
used in most ESR ope ra t ions i s a
co m b i n a t i o n o f C a O ,
C aF
2
a n d
A l
2
0
3
.
I t has been shown tha t i t is possib le to
increase the Al con ten t to seve ra l
t imes the in i t i a l me l t amoun t by reac
t ion w i th the A l
2
0
3
(Ref. 5).
A fu r the r check on the e f fec t o f a l u
m i n u m w a s m a d e b y a d d i n g a l u
m inu m to a we ld po o l o f a heat o f stee l
p rod uc in g a h igh D /W. A n a rc and
mo l ten poo l we re es tab l i shed on a
ro ta t ing bar and a 0 .020 in . (0 .508
m m ) d i a m a l u m i n u m r o d w a s t o u ch e d
to the edge o f the
p o o l .
The we ld poo l
ins tan t l y w idened and the pene t ra
t i o n d e c r e a se d . T h i s b e h a v i o r p e r
s iste d fo r abou t V i in . (12 .7 mm ) o f
we ld a t we ld ing s peed s o f 5 ipm (127
m m / m i n ) . T h e w e l d t h e n r e t u r n e d t o
i t s o r ig ina l d ime ns io ns . Th is p ro
ce d u r e w a s r e p e a t e d m a n y t i m e s w i t h
a l u m i n u m a d d i t i o n s o f a b o u t Vz w t %
up to 4 w t%. Inc reas ing the am oun t o f
a lum inum d id no t change the we ld
d i m e n s i o n s i n t h e d o p e d a r e a .
Fu r the r , a lu m i num a dd i t io ns to 304
s ta in less s tee l p roduced no such
cha nge in a rc behav io r o r D /W .
S t i l l pho t ogr aph s have been m ade
of 100 A arcs wi th 0 .060 in . arc
l eng ths . Rep resen ta t i ve pho tos a re
sho wn in F ig. 9 . Photo 9A is an arc on
hea t 81698 , a VAR hea t wh ich p ro
duces a h igh D/W and Photo 9B is an
arc on heat 82289, an ESR heat w i th a
low D /W. No te tha t 81698 p ro duc es a
typ ica l a rc w i th no unusua l fea tu res
whi le the arc o f 82289 f la res out a t the
wo rkp iece . Fu r the r , a do m e of l i gh t
su r rounds the a rc . A lso , 81698 , when
doped w i th a lum inum as in F ig . 9C ,
takes on an appea rance nea r l y i d e n
t ica l to 82289. Th is dome o f l igh t
shows up on a l l the low D/W heats.
Co lo r pho tos show th is dome to be a
deep b lue .
In an a t temp t to be t te r unde rs tand
the behav io r o f va r ious e lemen ts in
the a rc , the l i gh t f ro m the a rc was a na
l yzed w i th the ana ly t i ca l spec t ro -
g r a p h m e n t i o n e d e a r l i e r . T h e h y
po thes is was tha t an e lemen t pecu
l ia r to these heats o f stee l might be
en te r ing the a rc in s ign i f i can t quan t i
t i e s and a l te r ing the cu r ren t dens i ty o f
o the r c r i t i ca l pa rame te r o f the a rc .
A rc spec t ra f rom d i f fe ren t hea ts o f
s t e el w e r e r e co r d e d o n p h o t o g r a p h i c
p la tes and the va r ious e lemen ts p res
ent were ident i f ied by use o f ava i l
ab le s tanda rd p la tes p lus the MIT
wave length tab les . A l l ma jo r l i nes
we re ident i f ied as e i ther a rg on or
manganese . The in tens i t i es o f the im
pur i ty e lement l ines were in a l l cases
much less than a l l bu t the ve ry weak
l ines o f these two e lemen ts . Th is in
d ica tes tha t the impu r i t i e s do no t
a f fect the energy ba lance or o ther
p h y s i c a l p r o p e r t i e s o f t h e a r c
s ign i f i can t l y . A rough de te rm ina t ion o f
the abundance o f the a l loy e lemen ts
in the arc ind ica ted tha t they appear
in the o rde r o f the i r vapo r p ressu res :
M n , Cr, Fe, Ni.
S ince we ld behav io r seemed to be
co r re la ted w i th a lum inum con ten t , a
se t o f representa t ive l ines fo r the
p r o m i n e n t e l e m e n t s p l u s a l u m i n u m
were compared on th ree hea ts o f
me ta l a t two d i f fe ren t a rc c u r ren ts .
T h e a ve r a ge l i n e i n t e n s i t i e s f r o m
t h r e e e xp o su r e s m a d e a s t h e sa m p l e s
were ro ta ted a t a su r face s peed o f
5 ipm (127 mm/min ) a re show in
Tab le 8 .
These da ta ind ica te tha t the
v a r i
at ion o f a lu m inu m in the arc does not
d i f fe r s ign i f i can t l y f rom the va r ia t ion
of the major a l loy const i tuents in the
a rc . The re fo re , the a lum inum is no t
expected to have any more d i rec t
e f fect on the physics o f the arc than
m a n ga n e se o r ch r o m i u m .
Examina t ion o f a rcs w i th the mono -
chrometer sys tem showed tha t the
deep b lue l i gh t (descr ibed above ) i s
ch a r a c t e r i s t i c m a n ga n e se e m i ss i o n
and tha t a sma l l am oun t o f em iss ion
f r o m a d d e d a l u m i n u m i s o b se r ve d a t
the su r face o f the pudd le .
F i gu r e 1 0 sh o w s t h e sp e c t r u m
(be tween 3800 and 4400 angst roms)
o f l i gh t em i t ted f rom the a rea im
med ia te ly above the mo l ten poo l on a
low D /W hea t . F igu re 11 sh o w s t h e
sam e in fo rma t ion fo r a h igh D /W hea t .
The arcs in F igs. 10 , 11 , an d 12 we re
all run at 100 A, 0.060 in. (1.5 m m )
a rc leng th and 5 ipm (127 m m /m in )
we ld ing speed . The leng th o f the
va r ious l i nes is a mea su re o f the w id th
o f the arc over wh ich exi ta t ion is tak
ing p lace.
Nearly al l of the l ines visib le in
these spec t ra a re due to manganese .
A com par ison o f F igs . 10 and 11 w i th
9A and 9B shows tha t the extent o f
m a n ga n e se e m i ss i o n co r r e sp o n d s t o
the f la re o f b r igh t l igh t a t the work-
p iece su r face . Fo r compar ison , F ig .
12 shows the same spect ra l reg ion fo r
an arc on 304 sta in less stee l wh ich is
qu i te s im i la r to F ig. 11 . Th is is in go od
a g r e e m e n t w i t h t h e ir c o m p a r a t i ve
we ld ing behav io r .
The spec t ra l i n fo rma t ion p lus o the r
e xp e r i m e n t s d i scu sse d i n d i ca t e s t h a t
a l u m i n u m a n d m a n ga n e se so m e h o w
work in comb ina t ion to decrease the
D/W ra t io o f we lds in heats w i th
h ighe r a lum inum con ten t . The de ta i l s
o f such an in te rac t ion a re no t unde r
s t o o d , bu t a re curren t ly the sub ject o f
fu r the r inves t iga t ion .
C o n c l u s i o n s
1. The GTA we ld in g beh av io r o f
HMSS is qu i te va r iab le and can be
s ign i f i can t l y d i f fe ren t f rom tha t o f the
more conven t iona l aus ten i t i c s ta in
less stee ls.
2. P o r o s i t y , s u r f a c e r o u g h n e s s ,
and arc stab i l i ty o f VAR and ESR
HMSS we lds a re s t rong ly re la ted to
n i t rogen leve l . These we ld p rope r t ies
wi l l be opt imized i f n i t rogen content is
Fig. 9 — Typical arc appearance for a high D/W steel (left), a low D/W steel (center), and a high D/W steel doped with aluminum (right)
5 5 2 - s I D E C E M B E R 1 9 7 4
-
8/17/2019 GTA Weldability Studies on High
6/6
Fig.
10
— Region of spectrum from
a
weld
on a low D/W steel
kept at 0.30 wt% or less.
3. Porosity and surface roughness
of welds in airmelt HMSS are worse
than
in
remelted material and appar
ently are related to both nitrogen level
and oxide inclusion level.
4.
We lds in ESR ma terial may have
much lower penetration and lower
D/W than VAR and airmelt material.
5. The lower D/W of ESR welds is
related to a higher Al content in the
ESR m aterial and seems to be caused
by some as yet undefined interaction
between aluminum and manganese.
Acknowledgments
The authors wish to acknowledge the
assistance of Mr. R. F. Hillyer and Mr. D. H.
Riefenberg for the analysis of inclusions
and electrode deposits reported. Further,
thanks are extended to Mr. R. Acton of
Sandia Laboratories
for
the thermal
di f fu
sivity measurements.
The work was performe d under Con
tract AT(29-1)-1106 for the Albuquerque
T a b l e 8 -
- R e l a t i v e In t e n s i t i e s
o
R e p r e s e n t a t i v e
Di f f e r e n t S t e e l Sa
S a m p l e
no.
81143
82289
6 8 1 8
81143
82289
6818
mples
A r c
c u r r e n t ,
75
75
75
40
40
4 0
A Mn
2.7
10.6
6.4
2.0
4.0
3.2
L i n e s
or
Fe
1.0
5.5
3.1
0.9
0.7
1.0
Cr
1.6
7.5
4.5
1.2
2.3
1.6
Al
0.16
1.5
0 .20
0.23
2.0
0.46
Fig.
11
— Region of spectrum from a weld
on a high D/W steel
Operations Office of the
Energy Commission.
U.S. Atomic
References
1. Brook s, J. A., "Electron Beam Weld
ability of High Nitrogen Stainless Steel,"
SLL-73-0060, October 1973, Sandia Lab
oratories.
2. Ludwig, H. C, "Current Density and
Anode S pot Size in the Gas Tungsten A rc,"
Welding Journal, 47 5), May 1968, Res.
••
. • • • • .
• '• '
-
•
•• • - • • • • • • • ( ' • ' •
IBfe
•• ••••
,:'• •• '• • •'•• .^?'^VmM§SMWS>-k
• - - ' .
• • :
• • '-•
: . ; : i : -
:
:. : ••
• • ' ^ • • • - . ; • •
:
. . ; • ; .
•
:»:
> v s v • • ' • • • • ; • • • • ; , : . - .
.
:
. : - • • : 7 : \
:
-' ' •
\k
••
p ^
P ; • ' • -
:
. • :
Fig. 72 — Region of spectrum from a weld
on 304 stainless steel
Suppl. ,
234-3 to 240-s.
3. Chase, T. F., and Savage, W. F.,
"Effect of Anode Composit ion on Tung
sten Arc Characterist ics," Welding Jour
nal, 50 (11), Nov. 1971, Res. Suppl., 467-s
to 473-s.
4. Oyler, G. W., Matuszesk, R. A., and
Garr, C. R., "Why Some Heats of Stainless
Steel May Not Weld," Welding Journal,
46
(12),
Dec. 1967, 1006 to 1011.
5. Rundell, G. R., Simonds Steel Divi
sion,
Private Communication.
WRC
Bul le t in
No.
190
December 1973
F l u x e s a n d S l a g s
in
W e l d i n g '
byC.
E.Jackson
Prior to the publ icat ion of this inte rpre t ive repor t , users of covered electrode s,
submerged-arc and other f lux-control led welding processes hav e had ava i l ab l e
lit t le information
or
explana t ion
of
flux-slag tec hnolo gy.
In
spite
of
this lack
of
informat ion for the user , appl icat ion of welding processes ut i l izing f luxes has
been extens ive . The lack of ava i l ab l e in format ion has b e e n due in p a r t to the
propr i e t a ry n a tur e
of
f lux form ulat ions .
Prof.
J ack s o n ,
in his
interpre t ive repor t ,
has unvei led the secrecy to provide the reader wi th a comprehens ive r ev iew of the
formulat ion and funct ions of welding f luxes an d s lag s . It is hoped tha t a presen
tat ion of some of the pr inciples of we lding flux techno logy will provide an appre
ciation of improved quality
of weld
me ta l ob ta ined th rough s l ag /me ta l r eac t ions .
Publ icat ion of this pape r was spo nsored by the Interpre t ive Repo r ts Com mit tee
of the W elding Research Counci l . Th e pr ice
of
WRC B ulletin 190
is
$4.00 per copy.
Orders should be sent to the Welding Re search C ounci l, 345 Ea s t 47th Stree t , New
York, N.Y. 10017.
W E L D I N G R E S E A R C H S U PP L E M E NT
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