Effects of Manganese in Weld Metal
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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 , M A R C H , 1 98 0
S p o n s o r e d b y t h e A m e r i c a n W e l d i n g S o c i e t y a n d th e W e l d i n g R e s e ar c h C o u n c i l
l l
D r
Effect of Manganese on the
Microstructure and Proper t ies of
A l l -We ld -Me ta l Depos i t s
Going from 0.6 to 1.8 Mn increasingly refines weld
microstructures and promo tes acicular ferrite formation,
and optimal impact is attained with approxima tely 1.5%
Mn although strain aging affects notch toughness and
displaces optimum Mn to a higher concentration
BY G. M. EVANS
The ef fect of manga nese,
1.8 , on t he m ic ro -
2560)
ten
2
er 0.1% Mn add i t ion t o t he depos i t .
Charpy V, Schnadt and C O D tests
s -d epo s i t ed we ld meta ls in
ct prope r t ies bein g at ta ined at a
only a margin al e f fect on impa ct
marked ly a f f ec ted no tch t ough
ess and d isp laced the op t imum m a n
T h e wo r k i n g p r o g r a m o f S u b c o m -
o f t he I n te rna t iona l Inst i
W el di ng cal ls for a jo in t e f for t
t o s tudy t he m ic ros t ruc tu re o f we ld
meta l .
As a f i rs t s tep, four a l l - we ld
meta l depos i t s have been d is t r ibu ted
to va r ious labora to r ies w i t h recom
mendat ions ' f o r t he charac te r iza t ion
of the microstructural c o m p o n e n t s .
The present paper deta i ls the f i n d
ings of the Swiss delegat ion in co l labo
ra t ion w i t h t he W e ld ing I ns t i t u te
(Un i t ed K ingdom) . I n add i t ion t o t he
me tal log raph ic s tudies , a test program
was conduc ted t o eva lua te t he in
f luence of manganese on the tens i le
and impact proper t ies of the
w e l d
ments.
E x p e r i m e n t a l P r o c e d u r e
Electrodes
Four expe r imenta l i r on pow der t ype
basic e lect rod es, cod ed A , B, C and D,
Paper to be presented at the AW S 61st
Annual Meeting in Los Angeles, California,
during April 14-18, 1980.
G. M. EVANS is Chief Metallurgist, Weld ing
Industries Oerlikon Bueh rle Ltd., Zurich,
Switzerland.
were prepared us ing 4 mm (0.16
in.)
d iame te r co re w i re . The fe r ro -man ga-
nese contents of the coat ings were 3,
5, 7 and 9%, respect ive ly , and th e fe r ro-
s i l i con con ten t was ba lanced . The
coat ing factor was 1.70 and the e lec
trodes were baked for 1 h at 400°C
(752°F) to y ie ld a d i f fus ib le hyd roge n
content of 2 .3 ml/100 g deposi t ,
accord ing t o t he ISO procedure . -
Weld Preparation
The we ld p repara t ion emp loye d was
that spec i f ied in the Intern at ion al
Standard for the code of symbols for
manual meta l arc e lect rodes, namely
ISO 2560-1973.
Weld ing was done in t he f la t
pos i
t ion us ing the s t r inger bead technique.
Direct cur rent (e lect rode posi t ive) was
employed , t he amperage be ing 170 A,
the vo l t age 21 V and the hea t - inpu t
n o m in a l l y 1
k j / m m .
The in ter layer
tem pe ratu re w as 150° C (302°F).
Heat Treatment
The we ldments were t es ted in bo th
the as-welded and the s t ress- re l ieved
W E L D I N G R E SE A RC H S U P P L E M E N T I 67-s
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Table 1-VVeld Metal Composit ion (As-Welded), Wt-%
Electrode C Mn Si S O
A
B
C
D
0.035
0.038
0.049
0.051
0.66
1.00
1.42
1.82
0.30
0.30
0.34
0.34
0.006
0.005
0.005
0.006
0.013
0.014
0.013
0.017
0.007
0.010
0.009
0.009
0.049
0.046
0.041
0.039
(2 h/580°C or 2 h at 1076°F) co nd i t io n.
Impact tests (Charpy V notch) were
a lso conduc ted on s t ra in aged spec i
mens , compressed 10% and aged fo r
Vz
h at 250°C (482°F).
Mechanical Testing
Two sub-s ize a l l -we ld -meta l t ens i le
spec imens (M in i t r ac ) were mach ined
and tested for each type of e lect rode
and cond i t ion . A lso approx imate ly 35
Charpy V no tch spec imens were
st ruck, so as to obta in the complete
t rans i t ion curve.
Schnadt impact specimens
3
we r e
prepared f rom as -we lded depos i t s and
were t es ted under b radycoheracy (B„)
and tachycoheracy (K„) cond i t ions . I n
a d d i t i o n ,
as -we lded p la tes were C O D
tested in ful l thickness (20 mm or 0.79
in . ) a t t he We ld ing I ns t i t u te . The we ld
metal was saw notched (0.15 mm or
0.006 in . ) t ransversely to prov ide sub
s id iary- type specimens, as proposed in
D D 19 bu t w i t ho u t a f a t igue c rack .
Resul ts
Chemical Composition
Typical chemical analyses of the
deposi ts are g iven in Table 1. The
systemat ic increase in the amount of
fer ro-manganese in the coat ing re
sul ted in four d is t inct weld meta ls
conta in ing, nominal ly , 0 .65, 1.0, 1.4
and 1.8% Mn.
The we ld s i l i con con ten t was re la
t ive ly constant , but the carbon and
phosphorus con ten ts inc reased p ro
gress ive ly over the range. Weld meta l
oxygen leve l , on t he o ther h and ,
decreased, thus substant ia t ing the
deox ida t ion po ten t ia l o f manganese .
Essen t ial ly the same resu lts as give n in
Tab le 1 were ob ta ined on repea ted
analysis for the stress-relieved sam
ples.
Metallographic Examination
General. A t ransverse sect ion of one
o f the m u l t i - r u n depos i t s is show n in
Fig. 1, a to ta l o f n ine layers b eing
required to f i l l the gap. Three beads
were deposi ted per layer , and the
mac roscop ic ef fect was of repeated
sequences of as-deposi ted and super-
c r i t i ca l l y hea t -a f f ec ted we ld meta l
zones.
The w id ths o f t he co lumnar , coarse
gra ined and f ine gra ined regions were
measured in the ver t ica l mid-p lane
pos i t ion and the dup l ica te resu l t s ,
ob ta ined by examin ing as -we lded and
st ress- re l ieved specimens, are de
p ic te d in F ig. 2 . The pe rcentages o f the
Fig. 7—Cross section of multi-run depos it
5 -
LU
U_
O
LLI
o
<
LL
CC
ID
CO
Q .
O
s
o
LL
10
15
LLI
o
< 2 0
l -
cn
a
co lumnar
coarse
, I fine
g ra ined Jg ra ined
Plate
sur face
E
E
o
.c
u
>
o.
O
.c
O
• - S T R E S S - R E L I E V E D
Fig. 2 —Zone distribution along the vertical centerline position
Table
2—Zone
Percentages in the Equivalent
ISO-V
Notch Position (AW = As-Welded,
SR = Stress-Relieved)
Z o n e
C o l u m n a r
Coarse g ra ined
F ine g ra ined
A W
18
35
47
SR
32
24
42
A W
23
34
43
SR
19
35
46
A W
22
34
44
SR
12
37
51
A W
11
34
55
SR
20
37
45
Average
20
34
46
68-s l
M A R C H 1 9 80
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>: :;K> m
J H
of top heads (co
35 on reproduc
US
HP
V '
im.^MmM^iMmiM
Fig. 4—Photomicrographs of coarse grained
regions. X200 (reduced 35 on reproduc
tion)
..
•w t ' J S V ' * ' ••
V
••'••' i
F/g. 5—Photomicrographs of fine graine d
regions. X.315 (reduced 35 on reproduc
tion)
The w id th o f t he co lumnar reg ions
the va lues f o r dup l ica te spec i
ens scat ter ing to an equivalent
of the coarse and f ine gra ined regions
a t t he no t ch loca t ion was f ound to be
80%.
A s ligh t ve r ti ca l d isp lace men t
wou ld a f f ec t t he re la t i ve p ropor t ions
of the zones, s ince the low er runs
t e n d e d t o c o n t a i n w id e r c o l u m n a r
bands.
The co lumnar g ra ins b roadened as
the we ld p rogressed dur ing depos i
t i o n , due to t he ep i t ax ia l g rowth
e f f ec t . As an approx imat ion , however ,
i t can be presumed that the sequence
is repe t i t i ve t h ro ug hou t and tha t t he
cent ra l top bead and the adjacent
heat -af fected weld meta l serve to
character ize the bulk of the deposi t .
Typica l microst ructures of the four
manganese-con ta in ing we ld meta ls
are shown in Figs. 3, 4, and 5, for the
columnar , coarse gra ined and f ine
gra ined regions, respect ive ly .
Columnar Region. The top ce nt ra l
bead of each specimen was examined
a t X200 and quan t i t a t i ve me ta l log ra ph
ic meas ureme nts were m ade as de
scr ibed in Doc. I I -A-389-76
1
, using a
W E L D I N G R E SE A RC H S U P P L E M E N T I 69-s
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Fine grained
100
9 0
Fig. 6—Diagram of top bead and adjacent areas
Swif t po int counter . The area t raversed
measured 2.5 X 2.0 mm- (Fig. 6), and
500 poin ts were re corde d by each of
two invest igators.
T h re e m a jo r m i c r o s tr u c t u r a l c o m p o
nen ts (F ig . 3B) were iden t i f ied , nam e-
ly:
1. Pro -eu tec to id f e r r i t e ( l igh t e t ch
ing).
2. I n te rmed ia te lame l la r p rodu c ts ,
main ly fer r i te s ide p lates resembl ing
upper ba in i t e ( l igh t e t ch ing) .
3. Ac icu la r fer r i te , con sis t ing of a
f ine s t ruc tu re o f in te r lock ing f e r r i t e
p la tes (dark .e t ch ing) .
The resu l t s ob ta ined on po in t coun t
ing are plot ted in Fig. 7. I t can be seen
that the amount of ac icu lar fer r i te
increased markedly , a t the expense of
p ro -e u tec to id f e r r i t e , as t he m anga
nese content increased. Also, a c lear
t rend ex is ted for the in termediate
lame l la r component t o dec rease w i t h
increasing manganese.
Carbon repl icas of the top beads
we r e e x a m in e d a t t h e W e ld i n g Inst i
t u t e ,
in a t r ansm iss ion e lec t ron m ic ro
scope (TEM), and a l inear in tercept
method was app l ied a t a magn i f i ca t ion
of X2500. The results are given in Table
3, the values for the h igh manga nese
we lds be ing ind ica t ive o f t he ac icu la r
Table 3—Average Linear Intercept in Top
Beads of As-Welded and Stress-Relieved
Specimens
Average linear intercept,
jtm
Electrode
A
B
C
D
As
-depos
3.30
2.87
1.72
1.05
ted St
r
ess-relieved
3.96
2.60
1.70
1.59
ferr ite lath size.
Examina t ion o f t he rep l i cas showed
that there was a gradual t rans i t ion
be tween ac icu la r f e r r i t e and p ro -
eu tec to id f e r r i t e . A lso , t he d is t inc t ion
norma l ly made be tween the two
mic ros t ruc tu res in t he op t ica l m ic ro
scope was pure ly arb i t rary at h igh
m a g n i f i c a t i o n .
Smal l and widely d ispersed areas of
re ta ined aus ten i t e were observed on
the repl icas. The amount of austeni te
inc reased w i t h inc reas ing manganese
but only in the case of weld D was
suf f ic ient austeni te present (1%) to be
de tec ted by X- ray d i f f r ac t ion .
Al l
the
repl icas f rom st ress- re l ieved welds
cou ld be read i ly d is t ingu ished by t he
presence of gra in boundary carb ides
• ~AS WELDED
O-STRESS-flELIEVED
ACICULAR
FERRITE (3)
PRO-EUTECTOID
FERRITE (1)
0 5
K) 1-5
MANGANESE IN W E L D , .
Fig. 7—Effect of manganese on microstruc
ture of top bead
wh ic h we r e f o r m e d b y t h e t e m p e r i n g
out of the reta ined austeni te.
Any mar tens i t e wh ich m igh t have
fo rmed w i t h in t he re ta ined aus ten i t e
was d i f f ic u l t to detec t because of the
f ine scale of the s t ructure. Such ind ica
t ions o f mar tens i t e , as were f ou nd ,
were of considerably smal ler areas
than those repor ted by Gar land and
K i r k w o o d
5
as occu r r ing in submerge d
arc welds. Fur thermore, i t was not
poss ib le to ident i fy the areas as e i ther
la th or twinned mar tens i te or to assess
them quan t i t a t i ve ly .
Coarse Grained Region. P h o t o m i
crographs of the reheated weld meta l
t aken d i rec t ly be low the cen t ra l t op
bead are sho wn in Fig. 4 . W ith increas
ing manganese the s t ructure became
inc reas ing ly more dark e t ch ing , and
the p ro -eu tec to id f e r r i t e de l inea t ing
the pr ior austeni te gra in boundar ies
wh ich became f ine r and hence tended
to accentuate the coarse gra ined
na tu re o f t he zone . The fus ion bound
ary in the case of the lowest manga
nese w el d (A) was d i f f ic u l t to locate
microstructurally
but the segregat ion
bands ( r ipp les) could readi ly be seen
by vary ing the focus.
7
E
Q 5
O
O 1
As
1
deposited region.
Reheated region.
-
/
y y
X
^ ^-'
,
y-
W.I.
A .
J
-
/
C ,
..-
A
y- -
--'
0 200 400 600 800 1000
NUMBER OF GRAIN BOUNDARIES INTERCEPTED .
Fig.
8—Grain
boundaries intercepted on
traversing as-deposited and reheated re
gions
Table 4—Linear Intercept Results From Fine Grained Region
(H
= hor izontal,
V = vertical)
I n te rcep t
per mm
155
146
Rat io
1.06
I n t e r c e p t / m m
150
a
s
c
Interval / (fi)
6.7
P'
/2
, m m '-'
12.22
B
C
D
H
V
H
V
H
V
173
171
199
208
237
253
1.01
0.96
0.94
172
203
245
5.8
4.9
4.1
13.13
14.28
15.62
70-s I M A R C H 1 9 8 0
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T h e m i c r o s t r u c t u r e w i t h i n t h e p r o -
c t o i d f e r r i te e n v e l o p e s a p p e a r e d
o p t i c a l l y i d e n t i c a l t o t h e a c i c u l a r
o c c u r r i n g in t h e a s - d e p o s i t e d
e l d m e t a l . T h e a r ea s s u r r o u n d e d b y
p r o - e u t e c t o i d f e r r i te d i f f e r e d i n
i ze a n d t h e b o u n d a r y o f t h e c o a r s e
e d z o n e w a s d i f f i c u l t t o l o c a t e ,
i n c e t h e m i c r o s t r u c t u r e t e n d e d t o b e
e p e n d e n t o n t h e u n d e r l y i n g s o l i d i f i
t r a n s f o r m a t i o n p a t t e r n .
l a tt e r p h e n o m e n o n w a s p a r t i c u
l a r ly n o t i c e a b l e a t t h e p e r i p h e r y o f t h e
o p b e a d w h e r e t h e h e a t - a f f e c t e d
o n e w e l d m e t a l ha d t r a n s f o r m e d
a c k i n t o c o l u m n a r t y p e g r a i n s . A l s o ,
i n t e r a c t i o n o c c u r r e d b e t w e e n super
i m p o s e d h e a t - a f f e c t e d z o n e s , a t y p i c a l
o c c u r r e n c e b e i n g t h e c o n t i n u a t i o n o f
a f i n e g r a i n e d r e g i o n i n t o a c o a r s e
g r a i n e d r e g i o n at t h e p o i n t o f i n t e r c e p
t i o n w i t h a n e w f u s i o n b o u n d a r y . T h e
d e p o s i t i o n s e q u e n c e , h o w e v e r , w a s
s u c h t h a t o v e r l a p p i n g o f h e a t - a f f e c t e d
z o n e s d i d n o t o c c u r at t h e C h V - n o t c h
l o c a t i o n .
T h e s c a n n i n g e l e c t r o n m i c r o s c o p e
( S E M ) w a s u s e d at t h e W e l d i n g
I n s t i
t u t e t o s t u d y t h e a s - d e p o s i t e d a n d
r e h e a t e d r e g i o n s o f t h e w e l d m e n t s . A
l i n e a r i n t e r c e p t m e t h o d w a s a p p l i e d
a n d t h e r e s u l ts o b t a i n e d f o r a s - w e l d e d
s p e c i m e n s a r e g i v e n i n F i g . 8 , t h e
c h a n g e in i n t e r c e p t b e i n g m o n o t o n i c
w i t h i n c r e a s i n g m a n g a n e s e . T h e f u s i o n
b o u n d a r i e s w e r e c l e a r l y v i s i b l e , a n d
t h e r e w a s a l s o a s u d d e n c h a n g e i n
l i n e a r i n t e r c e p t w h e n t h e b o u n d a r i e s
w e r e c r o s s e d . T h e b o u n d a r i e s b e
t w e e n t h e i n t e r c r i t i c a l l y a n d f u l l y
r e h e a t e d r e g i o n s , h o w e v e r , c o u l d n o t
b e l o c a t e d b y d i r e c t o b s e r v a t i o n , n o r
w e r e t h e y d e t e c t e d b y t h e i n t e r c e p t
m e a s u r e m e n t s ( F i g . 8 ) , s i n c e l i t t l e o r
n o d i s c o n t i n u i t y o f s l o p e o c c u r r e d
w i t h i n th e r e h e a t e d r e g i o n s .
Fine Grained Region. T h e f i n e
g r a i n e d r e g i o n s ( F ig . 6 ) w e r e p h o t o
g r a p h e d a t X 6 3 0 , a n d l i n e a r i n t e r c e p t s
o f g r a i n b o u n d a r i e s w e r e m a d e a s
d e s c r i b e d i n D o c . I I - A - 3 8 9 - 7 6 . T h e
r e s u l ts o b t a i n e d f o r t h e v e r t i c a l
( t h r o u g h - t h i c k n e s s ) a n d t h e h o r i z o n
t a l d i r e c t i o n s a r e g i v e n i n T a b l e 4 a n d
s h o w a f a ir d e g r e e o f e q u i a x i a l i t y .
T h e r e c i p r o c a l o f t h e s q u a r e r o o t o f
t h e m e a n g r a i n i n t e r v a l is p l o t t e d ,
a g a i n s t w e l d m e t a l m a n g a n e s e c o n
t e n t , i n F ig . 9 . A s t r a i g h t - l i n e r e l a t i o n
s h i p w a s o b t a i n e d , m a n g a n e s e a g a i n
b e i n g f o u n d t o h a v e a m o n o t o n i c
i n f l u e n c e . O f p a r t i c u l a r i n t e r e s t is t h a t
t h e p r e s e n t g r a i n s i ze m e a s u r e m e n t s
c a n v i r t u a l l y b e s u p e r i m p o s e d o n
t h o s e r e p o r t e d b y T u l i a n i
6
f o r r e h e a t e d
r u n s o f s u b m e r g e d a rc w e l d m e t a l .
M e ch a n i ca l P r o p e r t i e s
Tensile Results. T h e t e n s i l e t e s t d a t a
o b t a i n e d a r e g i v e n i n T a b l e 5 f o r b o t h
t h e a s - w e l d e d a n d s t r e s s - r e l i e v e d c o n -
5 0 5
1 0 1-5
M A N GA N E S E IN W E L D ,
2 0
Fig. 9—Effect of mang anese on the mean linear grain intercept (fine grained
region)
T a b l e 5-Tensile Test Resul ts
1
1
C o n d i t i o n
A s - w e l d e d
Stress-re l ieved
Electrode
A
B
C
D
A
B
C
D
YS
392
413
468
514
370
402
436
479
N/mm
1
UTS
466
498
551
588
456
490
529
576
°c
El
31.9
31.2
29.4
28.0
35.2
31.0
31.6
27.4
RA
80.6
80.6
78.7
76.8
80.6
80.6
78.8
76.9
11
YS—yield s t r e n g t h ; UTS—ultimate t e n s i l e s t r e n g t h ; E l — e l o n g a t i o n ; RA—reduction in area.
E
z
c/)
6 0 0
5 5 0
SOO
4 5 0
4 0 0
3 5 0
1
A
^W
y
- &
• /
y
P-
y
y
y
y
1 1 1
B C J ^ U X S . -
y &
y^ s
^y s
y^s'
y '
Y.S.
y
*'
y^ y
s y
.— y —
y
y^ y
/ • y '
s * * • A S W E L D E D
O S T R E S S - R E L I E V E D
1 1 1
0 - 5 1 0
1-5
2 0
M A N G A N E S E I N W E L D , % .
Fig. 10— Effect of man ganese on the tensile properties of multi-run deposits
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 71-s
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2 5 0
2 0 0
^150
aa
UJ
5
1 0 0
a
UJ
DO
a
o
S2 5 °
CO
<
A
B
C
D-
I I I I
C h a r p y
- ' ' / /
/ / /
1
i:
If \
/ / /
/
/ •', /
• / • ' • /
/
-yy
i i i i
i
- V
fy
i
i
.-——
i
- 8 0 - 6 0 - 4 0 - 2 0 0 2 0
T E S T T E M P E R A T U R E , °C .
Fig. 11—Charpy
V-notch
impact results (as-welded)
3 0
2 0
E
a
10
4 0
^
3 0
> •
a
tr
UJ
UJ
2 0
Q
UJ
m
cr
8
10
CO
<
0
I
A
B
C
D
i
I I I I I
S c h n a d t ,
K
0
y_
,yy
.• j
/ • ' n
/•'
/
/ 1
i i
i
1
y
/in
1 i
*
•/My
-y
i i i i
-
_
- 1 5
10
E
a
- 5
-80 -60 -40 -20 0 20
T E S T T E M P E R A T U R E , ° C .
Fig. 13—Schnadt impac t test results K„ (as-welded)
1 2
1 0
E
E
^ S
a
o
o
<
o
on
o
0-8
0 -6 -
0-2
I I
A
_ B
c
D
| COD
-
-
..- y
.I I
I
clip
f
>' /
/
'/ y
gauge
I
l im i t .
I
-
-
-
- 2 0 0
-150 -100
T E S T T E M P E R A T U R E ,
Fig. 12-COD test results (as-welded)
d i t i o n s . Y i e l d s t r e n g t h a n d u l t i m a t e
t e n s i l e s t r e n g t h a r e p l o t t e d i n F i g . 1 0
a n d a r e s e e n t o i n c r e a s e l i n e a r l y w i t h
i n c r e a s i n g m a n g a n e s e .
F or t h e a s - w e l d e d c o n d i t i o n , t h e
r e su l t s ( i n
N / m m
2
)
a r e d e s c r i b e d as
f o l l o w s w h e r e Y S is y i e l d s t r e n g t h a n d
U T S is u l t i m a t e t e n s i l e s t r e n g t h :
YS =3 1 4 + 1 0 8 M n ( 1 )
U T S = 3 9 4 + 1 08 M n ( 2 ) .
F or t h e s t re s s - r e l i e v e d c o n d i t i o n , t h e
e q u i v a l e n t e q u a t i o n s w e r e c a l c u l a t e d
t o b e :
3
C .
• 5 0
- 8 0 - 6 0 - 4 0 - 2 0 0
T E S T T E M P E R A T U R E
2 0
Fig. 14—Schnadt impact test results
C
(as-welded)
Y S = 3 1 1 + 8 9 M n ( 3 )
U T S = 3 9 0 + 9 8 M n ( 4 ) .
F or t h e s p e c i f i c w e l d i n g c o n d i t i o n s
e m p l o y e d , it w a s f o u n d t h a t a n
i n c r e a s e o f 0 . 1 % m a n g a n e s e i n t h e
d e p o s i t in c r e a s e d t h e t e n s i l e p a r a m e
t er s b y a p p r o x i m a t e l y 1 0 N / m m - .
S t re s s r e l i e v i n g o f t h e s y s t e m ( C - M n )
i n d u c e d t h e t e n s i l e p a r a m e t e r s t o
d e c r e a s e , t h e d r o p b e i n g d e p e n d e n t
o n t h e m a n g a n e s e l e v e l .
Toughness Results. T h e C h a r p y V
t r a n s i t i o n c u r v e s f o r a s - w e l d e d d e p o s
i t s a r e g i ve n i n F i g . 1 1 . T h e C O D t e s t
r e s u l ts o b t a i n e d f o r s a w n o t c h e d s p e c
i m e n s a r e p l o t t e d i n F ig . 1 2 a n d t h e
Sc h n a d t te s t r e su l t s a r e g i v e n i n F i g s .
1 3 a n d 1 4 f o r t h e K„ a n d B„ c o n d i t i o n s ,
r e s p e c t i v e l y .
T h e d a t a a r e r e p l o t t e d c o n s e c u t i v e l y
i n F i g s. 1 5 t o 1 8 , a s a f u n c t i o n o f w e l d
m e t a l m a n g a n e s e a n d i t is s e e n t h a t
t h e f o u r d i f f e r e n t t es t p r o c e d u r e s
e x h i b i t e d t h e s a m e g e n e r a l t r e n d s .
I n c r e a s in g m a n g a n e s e l o w e r e d t h e
u p p e r s h e l f a n d d i s p l a c e d t h e t r a n s i
t i o n c u r v e s t o l o w e r t e m p e r a t u r e s u n t i l
a n o p t i m u m c o n d i t i o n h a d b e e n
a t t a i n e d at a m a n g a n e s e c o n t e n t o f
a p p r o x i m a t e l y 1 . 5 % . T h e r e a f t e r , i n
c r e a s in g m a n g a n e s e b e c a m e d e l e t e r i -
7 2 - s l M A R C H 1 9 8 0
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2 5 0
2 0 0
^ 1 5 0 -
O
c
U J
5
1 0 0
a
U J
DQ
C C
o
W 5 0
<
Cha r py -V
0-5 1 0 1-5 2 0
M A N G A N E S E IN W E L D , % .
Fig.
15—Effect
of manganese (Charpy V-notch)
0-5
1 0 1-5
M A N G A N E S E I N W E L D
%
Fig. 17—Effect of manganese (Schnadt K„)
ous, except at very low temperatures
where the lower shel f was ra ised.
The Charpy V-no tch impac t cu rves
for s t ress- re l ieved deposi ts are p lot ted
in Fig. 19 and th e data are recons idered
in Fig. 20, as a fun ct i on of manga nese.
Co m p a r i s o n w i t h t h e a s - we ld e d c o n
di t io n (F ig. 11) ind ica tes on ly a s l ight
d isp lacement , t he hea t t r ea tment hav
ing had a ben ef ic ia l e f fect at low
m a n
ganese and a de t r im en ta l e f fect at h igh
manganese contents . The extent of the
tempera tu re d isp lacement , a t t he 100
J
leve l ,
is given in Table 6.
The Charpy V curves obta ined on
test ing s t ra in aged impact specimens
are sho wn in Fig. 21 and the equ ivale nt
resul ts are p lot ted against manganese
3 0
2 0
E
a
1 0
0-5
1 0 T 5
MANGANE S E
IN
W E L D %
2 0
Fig. 16—Effect oi manganese (COD test, 20 x 26 mm, i.e.,
0.79
x
1.02
in.)
4 0 -
-
3 0 ( -
C D
or
LU
UJ 2 0
a
U J
CD
ce
O
CD
<
1
A
-
1
B
1
1
C
Schnadt
i
B o
1
D
•^-40°C
~~-50°
^^ -6 0°
~ ^- 70 °
.- 80 °
i
- 15
1 0
E
a
1 0 -
0 5 1 0 1-5 2 0
M A N G A N E S E IN W E L D , % .
Fig. 18—Effect of manganese (Schnadt B„)
con ten t in F ig. 22. Ag ing d isp la ced the
curves to h igher temperatures, the
shif t at the 100
J
level being repor ted in
Table 7.
The la tera l sh i f t to h igher tempera
tures d i f fered accord ing to manganese
con ten t , a t t a in ing a ma x im um (C) and
then dec reas ing at the h ighes t co nce n
t rat ion inve st igate d. The overa l l e f fect
was f o r e lec t rode D to become the
best of the ser ies and for the opt imum
to be d isp laced re lat ive to that exhib
i ted for as-welded and st ress- re l ieved
deposi ts .
Di s c u s s i o n
The meta l lographic s tudies of the
four d i f f e ren t m angan ese-con ta in ing
deposi ts revealed marked d i f ferences
in microst ructure. In as-deposi ted
we ld m eta l , as exem pl i f ied by t he t op
cent ra l bead, increasing amounts of
manganese progress ive ly increased the
amount of ac icu lar fer r i te , a t the
expense o f p ro -e u tec to id f e r r i t e and o f
in te rmed ia te lame l la r component . Fur
t he rmore , t he ac icu la r f e r r i t e , per se,
became progress ive ly more ref ined
(Table 3) . The rehe ated region s w ere
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2 5 0
2 0 0
^1501-
O
LU
5
1 C
Q
UJ
CD
CC
O
en
5 0
CO
<
A -
B -
c -
D
-
I i i
C h a r p y - V
1
1 /
/
•/•-
/ /
f t
/ / /
/ , • ' /
/ / / /
/ , • /
/ / /
/
/ /
/
y
i
S T R E S S -
1 1 1
1
•RELIEVED
,
2 5 0
- 3 0
2 0
E
Q.
10
- 8 0 - 6 0 - 4 0 - 2 0 0 2 0
T E S T
T E M P E R A T U R E ,
°C.
Fig. 19—Charpy
V-notch
impact results (stress relieved)
C h a r p y - V
D
RELIEVED
3 0
2 0
E
1-
a
1 0
1 0 1 5 2 0
M A N G A N E S E IN W E L D , % .
Fig.
20—Effect of manganese (Ch V, stress relieved)
s imi lar ly af fected, the coarse gra ined
and the f ine gra ined zones a lso
becoming increasingly f iner . The over
a l l in f luence o f manganese on m ic ro -
st ructure thus appeared to be benef i
c ia l t h roughou t , t he measured param
e te rs chang ing m ono ton ic a l l y .
The spec i f i c we ld ing cond i t ions em
plo yed w ere such as to indu ce th e
larger por t ion of the cent ra l par t o f the
ISO 2560 de pos its to recry stall ize . For
example , a t t he Charpy V-no tch loca
t i o n , i t was fo un d, on the average, that
only 20% of the s t ructure rema ined in
the co lumnar f o rm . The amount o f
recrysta l l iza t ion is cons idere d to be an
im p o r t a n t f a c t o r i n f l u e n c in g m e c h a n
ical propert ies
7 51
and must there fore be
borne in m ind when a t t empt ing t o
eva lua te t he in f luence o f a l loy ing e le
ments.
Tensi le tests resul ts conf i rm that
manganese increases the y ie ld
st rength and tens i le s t rength of i r o n -
manganese alloys.
11
For the range of
manganese con ten ts inves t iga ted ,
so l
i d so lu t ion harden ing and g ra in re f ine
ment led to a l inear in f luence, an
increase of 0.1% M n increasing the
tensi le parameters by 10 N/mm
2
The
lat ter va lue compares favorably , but
perhaps inadver ten t ly , t o t ha t quo ted
by Bra in and Smith
1
for mi ld s teel CO;,
weld meta l and by Tu l ian i
6
for sub
merged arc weld meta l .
The tens i le proper t ies decreased
af ter s tress re l iev ing , the d rop bein g
greater in the case of yield strength
and h igh manganese levels . Carb ide
prec ip i t a t ion occur red a t g ra in bound
ar ies dur ing the heat t reatment , but
ev iden t ly no secondary harden ing oc
cur red in t he p la in C-Mn we ld meta l
svstem over t he t ime invo lved .
Table 6 -
Electroc
A
B
C
D
Effect of St
Temp.
e A W
- 2 7
- 4 4
- 5 3
- 4 3
ress
Relief
°C at 100 |
SR
- 3 2
- 4 4
- 5 0
- 3 6
(at 100 J)
D i sp l a ce
ment ,
°C
- 5
0
+ 3
+ 7
' AW— as-weld ed; SR—stress-relieved.
°F = (9/5)°C + 32
The toughness da ta ob ta ined us ing
the Charpy V-no tch , Schnad t (K
(
, and
B„)
and COD test revealed the same
general t rend in all cases. Thus, it can
be conc luded tha t t he un ive rsa l Char
py V test can be conf ident ly appl ied
for rout ine c lass i f icat ion of e lect rodes
according to ISO 2560. In pract ical
app l ica t ions , however , when cons ider
ing proper t ies in the fu l l th ickness of
the jo int , the COD test is a requis i te
for evaluat ing f i tness for purpose and
de term in in g cr i t ica l defect s izes. A
poss ib le co r re la t ion ex is t ing be tween
Charpy V-no tch and COD perhaps
only appl ies when the extent of s t ra in
ag ing is low. Fur thermore , a re la t ion
sh ip cou ld poss ib ly be on ly expec ted
wh en the e lec t rodes com pared a re , as
in the present instance, of the same
slag-base type.
In
accord w i t h Nakayama et al. it
was found that increasing manganese
decreased the upper shel f o f the t r a n
s i t ion curves. The increasing y ie ld
st reng th resul ted in a greater ten den cy
to m ic rovo id coa lescence dur ing t he
duct i le mode of f racture. In cont rast ,
manganese had a bene f ic ia l in f luence
on the lower shel f due to the ef fect on
cleavage resistance.
9
In the t rans i t ion region of the
impact curves for as-welded deposi ts ,
manganese had an op t im um in f luenc e
at 1.5% manganese, despi te the pro
g ress ive improvement in m ic ros t ruc
t u re t h roughou t . The pa t t e rn o f behav
ior is t hus depe nden t on t he c om pet
ing act ions of the e lement to :
1. Increase the y ie ld s t rength.
2. Increase the ac icu lar fer r i te v o l
ume f ract ion and to ref ine the gra in
s ize in the reheated region.
St ress re l iev ing of the deposi ts had
v i r t ua l l y no in f luence on t he Charpy
V-n otc h test resul ts , and peak p roper
t ies we re a lso exh ib i te d at the 1.5% M n
leve l . Fur thermore, i t appears that the
decrease in toughness expe cted as a
resul t o f carb ide prec ip i ta t ion was
compensa ted f o r by an oppos ing
me cha nism , e.g., a sof te ning o f th e
ferr ite.
St ra in aging of the four exper imenta l
we ld meta ls induced a cons iderab le
degree o f embr i t t lement .
In
C - M n
depos i ts i t is general ly ac cepte d tha t
the major so lute causing the decrease
in resistance to cleavage fracture is
n i t r o g e n . W ith in th e range of scat ter ,
no t rend in n i t rogen content ex is ted
over the range of manganese contents
s t u d i e d ,
t he va lues be ing be tween 69
and 96 ppm. Manganese is repor ted
1
'
2
t o d im in ish t he ag ing t endency o f
steel,
and op in io n var ies as to w he the r
the e leme nt shou ld be jud ge d on i ts
o wn m e r i t s o r wh e t h e r t h e c o m b in e d
ef fect of manganese and carbon is of
greater s igni f icance. The re lat ive d is
p lacement on s t ra in aging (Table 7)
was inconsis tent and the reason
rema ins en igmat ic , o ther t han t ha t
g ra in re f inement a lone becomes the
con t ro l l ing f ac to r . The observed t rend
74-sl MA RC H 1980
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i OU
2 0 0
—
1
^150
a
UJ
z
m
100
Q
UJ
CD
QC
O
v> 5 0
CO
<
0
I
A
B —
c — -
_ D
-
STRAIN
I
I
~
AGED
I
I I I I
Charpy -V
/
yS7
/ / / /
• / / /
i'
f
/
nil -
/ ii/
' y
i i i i
- 3 0
- 8 0 - 6 0 - 4 0 - 2 0 0 2 0
TEST TEMPE RATURE ,°C .
Fig. 21—Charpy
V-notch
impact results (strain aged)
- 2 0
E
f
j
- 1 0
2 5 0
2 0 0
C h a r p y - V
3 0
2 0
E
Q.
10
10 T5
MANGANESE IN WELD ,5
Fig. 22—Effect of manganese (Ch V, strain aged).
w a s s u c h t h a t d e p o s i t D e x h i b i t e d t h e
b e s t i m p a c t p r o p e r t i e s , t h e o p t i m u m
b e i n g d i s p l a c e d a w a y f r o m t h e p r e
v i o u s l e v e l o f 1.5 % M n .
T h e p r e s e n t w o r k is c o n s i d e r e d a s a n
i n i t i a l s t e p f o r t h e u l t i m a t e u n d e r
s t a n d i n g o f t h e r o l e o f m i c r o s t r u c t u r e
i n m u l t i - r u n m a n u a l m e t a l a r c d e p o s
i ts .
E v e n t u a l l y , it is i n t e n d e d t o a d d
a l l o y i n g e l e m e n t s , e . g ., M o , N i a n d C r ,
t o t h e f o u r d i f f e r e n t m a n g a n e s e l e v e ls
a n d e v a l u a t e t h e c h a n g e s i n s t r u c t u r e
a n d p r o p e r t i e s . F i r s tl y , h o w e v e r , it is
f e l t t h a t f u r t h e r w o r k s h o u l d b e c o n
d u c t e d o n t h e C - M n s y s t e m s o a s t o
a p p r e c i a t e t h e p a r t p l a y e d b y c a r b i d e
d i s t r i b u t i o n a n d m o r p h o l o g y . T o f a c i l i
t a t e t h i s , i t is i n t e n d e d t o s t u d y t h e
f o u r w e l d m e n t s in t h e n o r m a l i z e d a n d
n o r m a l i z e d - a n d - t e m p e r e d c o n d i t i o n s .
C o n c l u s i o n s
F o r I S O 2 5 6 0 w e l d m e n t s d e p o s i t e d
a t 1 k j / m m w i t h b a s i c e l e c t r o d e s o f a
s p e c i f ic s l a g -b a s e t y p e , t h e f o l l o w i n g
c o n c l u s i o n s a p p l i e d :
1.
I n c r e a s i n g m a n g a n e s e , i n t h e
r a n g e 0 . 6 t o 1 .8 % , i n c r e a se d t h e
a m o u n t o f a c i c u l a r f e r r i t e i n a s - d e p o s
i t e d w e l d m e t a l a n d d e c r e a s e d t h e
a m o u n t o f p r o - e u t e c t o i d f e r r i t e a n d
i n t e r m e d i a t e c o m p o n e n t .
2. I n c r e a s i n g m a n g a n e s e r e f i n e d t h e
a c i c u l a r f e r r i t e in t h e a s - d e p o s i t e d
w e l d m e t a l .
3 . I n c r e a s i n g m a n g a n e s e r e f i n e d t h e
c o a r s e g r a i n e d r e g i o n o f t h e h e a t -
a f f e c t e d w e l d m e t a l .
4.
I n c r e a s i n g m a n g a n e s e r e d u c e d
t h e g r a i n s iz e o f t h e e q u i a x e d f i n e
g r a i n e d z o n e o f t h e h e a t - a f f e c t e d
w e l d m e t a l .
T a b l e 7 - E f f e c t of Strain
Electrode
A
B
C
D
T e m p .
A W
- 2 7
- 4 4
- 5 3
- 4 3
Ag i n g
°C at 100 J
SR
+ 5
- 5
- 1 2
- 1 9
(a t 10 0 ))<*'
D i sp l a ce
ment
°C><
+ 32
+ 39
+ 41
+ 24
181
AW—as -welded; SR—stress-relieved.
°F = (9/5)°C + 32
5 . T h e y i e l d a n d t e n s i l e s t r e n g t h s o f
t h e d e p o s i t s i n c r e a s e d b y a p p r o x i
m a t e l y 1 0 N / m m
2
p e r 0 . 1 % i n c r e a s e o f
m a n g a n e s e .
6 . C h a r p y V - n o t c h , S c h n a d t
(K, ,
a n d
B
0
)
a n d C O D t e s t s g r a d e d t h e t e s t
w e l d s i n t h e s a m e r e l a t i v e o r d e r .
7 . T h e o p t i m u m i m p a c t p r o p e r t i e s
o f a s - w e l d e d a n d s t r e s s - r e l ie v e d d e
p o s i t s w e r e a t t a i n e d a t 1 .5 % M n , d u e
t o t h e c o m p e t i t i v e i n f l u e n c e o f y i e l d
s t r e n g t h a n d m i c r o s t r u c t u r e .
8 . S t r a in a g i n g e m b r i t t l e d t h e d e
p o s i t s a n d c h a n g e d t h e r e l a t iv e o r d e r
s u c h t h a t o p t i m u m i m p a c t p r o p e r t i e s
w e r e a c h i e v e d at a h i g h e r m a n g a n e s e
c o n t e n t .
Ac/cnow/ec/gments
T h e a u t h o r w i s h e s t o e x p r e s s h i s
t h a n k s t o t h e st a ff o f t h e W e l d i n g
I n s t i t u t e fo r c o n d u c t i n g p a r t o f t h e
m e t a l l o g r a p h i c w o r k u n d e r c o n t r a c t .
I n p a r t i c u l a r , t h a n k s a r e e x t e n d e d t o
D r . R. E . D o l b y f o r s u p e r v i s i n g t h e
s t u d i e s .
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