CHAPTER-IV RESULT AND DISCUSSION - Shodhgangashodhganga.inflibnet.ac.in/bitstream/10603/93300/14/14chapter 4.pdf · were selected from the weld coupon as per ASME Section VIII, Diy

CHAPTER-IV

RESULT AND DISCUSSION

4.1 Introduction

4.2 Result of Notch tests

4.3 Result of Light Optical Microscopy (LaM)

4.4 Results of Scanning Electron Microscopy (SEM)

4.5 Result of Energy Dispersive X-Ray Spectroscopy (EDX)

Analysis

4.6 Result of Micro Hardness

4.7 Result of Hardness

4.8 Effect of Manganese

4.9 Effect of MnlSi and MnlS Ratio

4.10 Effect of Tempering Temperature

4.11 Effect of Position of Notch

4.12 Effect ofInclusion and Impurities

References

4.1 Introduction

CHAPTER-4

RESULT AND DISCUSSION

Many researchers arc at present studying the critical functional properties

of Cr-Mo-V steel material. The researcher has endeavour to study the effect of

microstructure on toughness. The process of welding is most important and very

complex because in weld solidification or phase transformation, thermal cycle

plays very important role. The final microstructure and mechanical properties of

weld metal broadly depends upon.

I. Base metal composition.

2. Welding process and parameter.

3. Pre and Post weld heat treatment.

4. Welding consumable.

The base material used in present study is 2.25 Cr-I Mo-O.25V steel.

The Submerged Arc welding with AC current is used to prepare weld coupon.

The parameters are selected on the basis of past experience, research study and

suggestion of consumable suppliers. (Ref table No. 3.6 & 3.7).

Thyssen Germany supplied different batches of weld consumables for welding of

above-mentioned 2 '4 Cr-I Mo- 1/4 V Steel coupons. Four types of consumables

have been tested during these experiments -i.e Wire-Union S I Cr Mo 2V and flux

UV - 430 TTRW composition. The main focus was on the notch toughness of the

joint at _300 C and above in 10 hrs Post Weld Heat Treatment i.e. Minimum

PWHT condition (Required notch toughness values: 48J minimum and

55J average at - 30° C as per ASME Section VIII, Div.2, Appendix-26). The use

of consumable batch No.4 and Trial SA W-4 gave necessary notch toughness

strength (Ref. Table No 4.7), while the other did not provide consistent values

(Ref. Table No. 4.4, 4.5 and 4.6) of notch toughness. The (. - Marked) samples

118

of four types of consumables SAW-I, SA W-2, SA W-3 and SA W-4 (Ref. Table

No. 4.4, 4.5,4_6 and 4.7) were tested for analysis and comparison purpose.

Samples were prepared with standard parameters (Ref. Table No.3.5), tested and

EDX, SEM, Hardness, Micro hardness and Light optical microscopy carried out.

The fOllr trials were carried Ollt as follows with four different consumables.

Table 4.1 Consumable Batch Number and Trhll Number

Wire: - Union S I Cr Mo 2V Flux: - UV 430 TTRW

Consumable-l Consumable-2 Consumable-3 Consumable-4

Consumable Trial SAW-l Trial SAW-2 Trial SAW-3 Trial SAW-4

Batch No. Batch No. Batch No. Batch No.

Wire 85944 762869 55155 763867

Flux 1400078 1401253 1401062 1401365

Table No.4.2 Properties and chemical composition of liller metal

C Si I\1n P S Cr 1\10 Ni

SAWI (8S944/14t)()()78) 0.10 0.06 0.58 o.om 0.00 I 2.58 0.99 D_16

SAW2 (76286911401253) D.IO D.12 0.92 D.006 O.OO} 2.36 I.D6 D.IS

SAW3 (55155/1401062) 0.12 0.08 1.11 0_004 0.005 2.3} O.Y7 0.13

SAW4 (763867/140\365) 0_11 D.07 1.22 D.(XJS 0.007 2.38 1.01 0.13

V AI eu N Nil Sn As SII SAWI(85944/14(Hltl78) 0.31 D_m o.m - 0.02 O.OO} O.OO} 0.0015

SA W2(762869/1401253) 0.25 - 0.06 - 0_024 0.004 D.002 O.(X)J

SA W 3(55155/1401062) 0.25 - 0.10 - O.tll5 0.004 0.001 O_OD I

SAW4(763867/140IJ6S) 0.24 D_D 12 D_09 O.ODS n.o 18 0.006 O.(X)!> 0.001

119

Table No. 4.3 Chemical composition of Cr-Mo-V Steel (permissible range of

alloying composition of filler mctal)[9]

ASME SEC VIII Div - 2 App - 26

C 1\ln Si Cr 1\10 P S V Cb

SAW 0.05 0.50 0.05 2.00 0.90 O.ot5 0.015 0.20 0.010

0.15 1.30 0.35 2.60 1.20 MAX MAX 0.40 0.040

All the four consumables contain chemical composition as per specified limits

(Ref. Table No. 4.2) given in the ASME Section VIII, Div. II App-26

(Ref. Table No. 4.3). However trial No. SA W - I, trial No. SAW - 2 and trial No.

SA W-3 consumable batches were disapproved because of inconsistent result of

notch toughness value. (Ref. Table. No. 4.4. 4.5 and 4.6). The salient discrepancy

between approved sample of trial No. SA W-4 and disapproved sample of trial No.

SAW-I, trial No. SAW-2 and trial No. SAW-3 is the manganese, silicon and

sulphur weight percentage.

4.2 Results of Impact Toughness Tests

The Notched-bar impact test was used to determine the tendency of a material to

behave in a ductile and brittle manner. This test is used for comparing the

influence of alloy and heat treatment on notch toughness. It is frequently used for

quality control of weld joints and weld acceptance purposes.

120

The notch toughness test carried out at three different temperatures. i.e. - 10°C,

-18°C, - 30°C in trial No. SAW - I, in the year of 2002-03. The trial No. SAW -

2 in the year of 2003-04, trial No. SAW - 3 in the year of 2004-05 and trial No.

SAW-4 in the year of 2005-06 were tested at - 30°C. The notch toughness yalues

were measured at 2mm from top and T/4 (10 mm) mm from bottom of weld in the

case of trial No. SAW-I ,2,3,4 (Ref. Fig. No. 4.1). The notch toughness specimens

were selected from the weld coupon as per ASME Section VIII, Diy. 2, Anicle T-

2 Notch Testing of Welds and Vessel Test Plates of Ferrous Materials, Clause No.

AT-201 and ASME Section VIII, Diy. I, UG-84 (h) (3) Charpy Notch Test.

- Te.1 I'ia-e - Top Weld I

~------~~~~~~====~~-I

~~ .. ,~ l ______________ ~~----_--~I--_--~~

Test Piece - Bottom Weld

Fig. 4.1 Top and Bottom Weld Sample Location on Test Coupon SA W-

1,2,3,4.

T.W. = Top Weld (Ref. Fig. No. 4.1)

B.W. = Bottom Weld (Ref. Fig. No. 4.1)

MITW - Min. PWHT Top Weld

MIBW - Min. PWHT Bottom Weld

121

Table 4.4 Notch Test Analyses -Minimum PWHT (trial No. SA W 1)

Wire: - Union S I er Mo 2V

Wire Batch No. 85944

Bottom Weld

Flux: - UV 430 TTRW

Flux Batch No. 1400078

Top Weld

Test Temp Sample No Impact Value Sample No Impact Value

-Iooe I 210 21 191 -Iooe 2 184 22 58 _lOoe 3 210 23 124 -lOoe 4 236 24 93 -Iooe 5 234 25 210 -Isoe 6 186 • 26 36 • -Isoe 7 34 • 27 118 -Isoe 8 154 2S 177 • -18°e 9 185 • 29 38 • -Isoe 10 44 • 30 166 • -Isoe II 260 31 63 -Isoe 12 276 32 190 -Isoe 13 IS4 33 36 -18°e 14 202 34 158 -18°e 15 222 35 164 -3Uoe 16 35 36 34 -30oe 17 23 37 42 -30oe 18 31 38 22 -30oe 19 34 39 28 -30oe 20 157 40 150

Bottom Weld: - T/4 mm from bottom of Weld

Top Weld : - 2 film from Top of Weld

• - Marked samples are tested for further detail investigation.

122

Table no - 4.5 Impact Test Analysis -Minimum PWHT (trial No. SAW 2)

Wire: - Union SI er Mo 2V Flux: - UV 430 TTRW

Wire Batch No. 762869 Flux Batch No. 1401253

Bottom Weld Top Weld

Test Temp Sample No Impact Value Sample No Impact Value

-30oe I 28 • 4 54 -30oe 2 128 • 5 22 • -30oe 3 116 6 132 •

Table no - 4.6 Impact Test Analysis -Minimum PWHT (trial No. SA W 3)

Wire: - Union S I Cr Mo 2V Flux: - UV 430 TTRW

Wire Butch No. 55155 Flux Batch No. 1401062

Bottom Weld Top Weld

Test Temp Sample No Impact Value Sample No Impact Value .

-30oe I 136 4 140 • -30oe 2 154 5 132 -30oe 3 156 6 94 •

Table no - 4.7 Impact Test Analysis -Minimum PWHT (trial No. SA W 4)

Wire: - Union S I er Mo 2V

Wire Batch No. 763867

Bottom Weld

Test Temp Sample No Impact Value

-30o e I 144 -30o e 2 140 -30o e 3 142 -30o e 4 152 -30o e 5 138

Flux: - UV 430 TTRW

Flux Batch No. 1401365

Top Weld

Sample No Impact Value

6 156 • 7 148 8 168 9 158 10 140 •

123

The Notch Toughness values of Trial No. SAW-I and SAW -2 (Ref. Table No. 4.4

and No. 4.5) show high-scattered results at - 30°C test temperature and trial

No. SA W-3 (Ref. Table No. 4.6) shows consistent result of notch toughness in

bottom weld and high scattered in notch toughness value in top weld compare to

notch toughness results of Trial No. SAW-4 (Ref. Table No. 4.7). so The

(. - Marked) samples of SAW-I, SAW -2 and SAW -3 were further investigated by

SEM, EDX, Micro hardness and light optical microscopy, because this sample did

not give consistent result of notch toughness. The samples of Trial No. SAW-4 is

also investigated by SEM and Light Optical Microscopy to strengthen the final

conclusion.

4.3 Result of Light Optical Microscopy (LOM)

A project work has been carried out to investigate the factors controlling the

microstructure developed in SAW AC welded test coupon of 2 1;.\ Cr- I Mo- 1;.\ V

base metal. Attention was paid to grain structure produced after minimum PWHT.

It is the structure that largely determined the fInal notch toughness properties of

weld specimen. The importance of defining and controlling the major SAW AC

welding variables in any procedure test or qualification program is endorsed by a

present work. In that selection of specific welding consumables and variables may

significantly vary the weld microstructure and notch toughness properties of weld.

Optical microscopy was c'lITied out with image analyzer and results are

summarized in various figures. Figure no. 4.2 shows microstructure of trial no.

SAW-I with different magnification and etchents. The details are as follows,

Fig. No.-4.2 A, Band C - 36J top weld.

Fig. No.-4.2 D -1771 top weld.

Fig. No.-4.2 E -1861 bottom weld.

Fig. No.-4.2 F - 341 bottom weld.

124

Optical microscopy was carried out with image analyzer and results are

summarized in various figures. Figure no. 4.3, 4.4, 4.5 show microstnIcture of

trial no. SA W-2 with different magnification and etchan!. The details are as

follows,

Fig. No.-4.3 A -Plate no. I to 6, 22J top weld.

Fig. No.-4.3 B -Plate no. 7 to 12, 22J top weld

Fig. NoA.4 A - Plate no. I to 6, 132J top weld.

Fig. NoA.4 B - Plate no.7 to 12, 132J top weld.

Fig. NO.-4.5 A and B -28J bottom weld.

Fig. No.-4.5 C and D -128J. bottom weld.

Optical mIcroscopy was carried out with image analyzer and results are

summarized in various figures. Figure no. 4.6 shows microstnIcture of trial no.

SA W-3 with different magnification and etchan!. The details are as follows,

Fig. No.-4.6 A, Band C 94J top weld.

Fig. No.-4.6 D, 140J top weld.

Optical mIcroscopy was carried out with image analyzer and results are

summarized in various figures. Figure no. 4.7 & 4.8 show microstructure of trial

no. SA W-4 with different magnification and etchan!. The details are as follows,

Fig. NO.-4.7 A -Plate no. I to 6 , 140J top weld.

Fig. No.-4.7 B -Plate no. 7 to 12, 140J top weld.

Fig. No.-4.8 A - Plate no. I to 6, 156J top weld.

Fig. No.-4.8 B - Plate no.7 to 12, 156J top weld.

125

r::\ Bh-d~;la~J? llr·' .' .

, 8ti,t.:" I~( .<;.""R.

The specimens are etched by 5% Nital [(SAW-I 34J,36J, I 86J, and 1771), (SAW

- 2, 1321,221), (SAW - 4, 1401, 156J) and 4% Picral [(SAW-I 361), (SAW-2

28J, 1281). The appropriate etching time from I min. to 1.5 min. was maintained

to reveal the good microstructure results. (Ref. Metal Handbook) The lower notch

toughness microstructure samples reveal the coarse grain and prior austenite grain

boundaries. It also reveals some bainitic structure with indication of localized

pearlite in the bead overlap area. These specimens are observed at L&T Ltd

Hazira. The specimens are etched with 5% Nital and KeIrn's reagent and Behera's

reagent to reveal the better microstructure resuIts[ 41]. Two Samples of 221 and

1321 of trial No. SA W-2 was observed with different magnification at TCR

Advance Engineering Pvt. Ltd., Baroda.

Table No. 4.8 Result of Light Optical Microscopy

Magnification Page Trial

Notch Value f'ig. No. Etching No. No. Etching with 5 with 4%

% Nital Picral

I SAW-I 341 (B/W) 4.2 (F) 200

2 SAW I 36 J (T/W) 4.2 (A,B,C) 50,ItKI,200 150,300,600

3 SAW-I 186 J (B/W) 4.2 (E) 200

3 SAW I 177 J (T/W) 4.2 (D) 200

4 SAW-2 28J (B/W) 4.5 (B,D) 1200,2400

5 SAW -2 128J (BAY) 4.5 (A,C) 1200, 2400

6 SAW-2 132 J (TAY) BW 4AA (P 1 to 6) 125,550, 1200

7 SAW-2 1321 (COLOUR) 4.4B (P 7 to 12) 125,550,1200

8 SAW-2 22J BW 4.3A (P 1 to 6) 125,550,1200

9 SAW-2 22J COLOUR 4.3B (P 7 to 12) 125,550,1200

lO SAW -3 94J (T/W) 4.6 (A,B,C) 150,300,600

11 SAW -3 140J (T/W) 4.6 (D) 600

12 SAW-4 140J (TW) 4.7A (P I to 6) 100,200,400,1000

13 SAW-4 140J (TW) 4.7B (P 7 to 12) 125,320,560, 1100

14 SAW-4 156J (TW) 4.8A (P 1 to 6) 100,200,400, I(KIO

15 SAW-4 156J (TW) 4.8Jl (P 7 to 12) 125,320,560,1100

16 SAW-4 140J (T/W) 4.9 (A) 1200

17 SAW-4 156J (T/W) 4.9 (B) 1200

126

The higher notch value of 132J, 140J, & 156J samples microstructure show

mixtures of fine well-tempered lower transformation products comprises of

martensite and bainite with carbides and ferrite. The grain structure is fine

indicating proper control of welding parameters including weld metal

temperature. (Ref. Fig. No. 4.4A, 4.7 A, 4.8A Plate I to 6»

The color metallography approach indicated no segregation at the prior austenite

grain boundaries from where the transformations have occurred. It helped in

confirming the presence of coarse mixture of under tempered lower

transformation products comprises of bainite and martensite. (Ref. Fig. No. 4.4B,

4.7B,4.8B Plate 7 to 12)

Color identification: Pinkish and reddish shade is on bainite, bluish and greenish

is on martcrnsite and white/yellowish/orange is on ferrite. The good notch

properties 132J, 140J, 156J are attributed to fine and uniform microstructure of

weld metal. (Ref. Fig. No. 4.4B, 4.7B, 4.8B- Plate 7 to 12)

127

(A) MITW-36J-4P-300X (8) MITW-36J-4P-lS0X

(C) MITW-36J-4P-200X (D) MITW-177J-SN-200X

(Ii:) MIBW-186J-SN-200X (F) MIBW-34J-SN-200X

Fig. No.:- 4.2 -Microstructure ofa fractured samples Cr-Mo-V steel weld mini. PWHT for CVN test at -1 ROC for SA W - 1

128

N \0

@ TCR ADVANCED ENGINEERING PVT. LTD., V ADODARA.

SAMPLE 022J

Plate: 4 (550X) I Plate: 5 (1200X) I Plata: 6

Fig.4.3A Microstructure of a Fractured Samples Cr-Mo-Y Steel Weld Min. PWHT for CYN test at -30°C for SAW 2

(2000X)

-w o

~ TCR ADVANCED ENGINEERING PVT. LTD., VADODARA.

SAMPLE 022J

Fig.4.3B Microstructure ofa Fractured Samples Cr-Mo-V Steel Weld Min. PWHT for CVN test at -30°C for SAW 2

-l;) -

@ TCR ADVANCED ENGINEERING PVT. LTD., VADODARA.

SAMPLE: 132J

Fig.4.4A Microstructure of a Fractured Samples Cr-Mo-V Steel Weld Min. PWHT for CVN test at -30°C for SAW 2

V-J tv

~ TCR ADVANCED ENGINEERING PVT. LTD., VADODARA.

SAMPLE: 132J


(A) Cr-Mo-V- J 28J- J 200X-4%P (8) Cr-Mo-V-28J-J200X-4%P

f:

T-ov-r .. " ~"'·r· "Y' \ ~7 ,",. ,'"

l :"' '; " •.. ' , '.',.\ >II """ .... " .• :' ".' ,.,. .• of , 1'" ... _~ ~

:1 .J ,' .• , .... " \ \)~~ . • .1 .. •• t .,~; " " .'.! . "l' ' .. ~' .. ' ... 1 . • '-' \. ',1 ,. '\";; i"· ;' ... I : ':'j.~'." . '. .... .', f I ..... I .. ..,;.! ,,~ ' ....

# .. :ti.:··~;\·d<~~~~.'~" .({~~. • ft t 1-.. ;trJ • . \ ,·'.1 'f' ., ...... ~:} ... <~ .f..~.\;.~'.~ 1 . '.' ~., ~.\.... ., ... ~.", .. ,r e ."'~"'. '. ',' l ,.~ ''f: ' ~ ~~ :f",1

"., • .,.-It. oj, '. • ,.,., . '1 ."/~.' .. -*. ·',"'ll., ,,_, )! . ... &." .;.J.,~,;, •..• ,.:. (,' .. "7\.,'

I' • .., ," •• ".,> ',~ .. ,<t •• • ,: .t; \, • . ,. I' .." '

•.... . "~ ,\ , '.., '~(.t{ '. \ If" 'r"~ ,{";,..,' ' .. ' .~ ... , .... -.~':1 \ ~,' ~ -." .f,.-,~ .. : ;'" . '.- .. " ' I' 0" .•• • I ,',.. \ ~

',. .,,') , :'\""" .', ••• 'j.."'''' 't .... ~--".~~II..:.......~ -

(C) Cr-Mo-V - J 28J-2400X-4% P (D) Cr-Mo-V -28J-2400X-4%P

Figure No.:- 4.5 -Microstructure of a fractured samples Cr-Mo-V steel weld mini. PWHT for CVN test at _3()OC For SA W 2

133

(A) l\IITW-94.J-SN-lS0X (8) l\IITW-94.T-SN-300X

(C) MITW-94J-SN-600X (0) l\IITW-140J-SN-600X

Fig. No.:- 4.6 -Microstructure of a fractured samples Cr-l\Io-V steel weld mini. PWHT for CVN test at -30°C. SA W -3

134

w u.

@ TCR ADVANCED ENGINEERING PVT. LTD., V ADODARA.

SAMPLE· 140J

Plate: 4

Fig. 4.7 A Microstructure of a Fractured Samples Cr-Mo- V Steel Weld Min. PWHT for CYN test at -30°C for SAW 4

(1000X)

l;.)

0\

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'_,C'f".' :::~ • • l4 ..... : -;""~'>":.":.: ~c.-~;jj>.' ~':;'-.~ ... '.:~": . • '." ~"\:.flrt- ~- r _ --'-, .- , "'~ .''f ' .. l;-,~ , .. .;: '.- ti' ~" , 're'" ;~; ...~

~'I<"'" ' .... ,."t".""'~. . ,~, ,. . "~ ..... '.~ . . "~"- . '--,' " : . ,,:.~,\ '.' -"f-'\~:~'" ~ ... ,. ~ .•• " - .. -. .," :ot. ...... .... ". ~ :,..,.-t.,.' .. ,. ';i-J". rt •. "~""';_·~' '\',.~~:. ... ,'!f",

" r-."'.,. . ,;' -,.,~ .Y'o'

. '~*.Ji};"~. ," " " .• ""t- of,.. .'. • - • ·"'\1,;:"'·~~;':~'~.4. ~.~",-r.~ .. ·~.~1 " <-~.; ... ", .

_~ :-;. If ",' .. :' r;~ ~,';~ .. ,,~ ~.~ JI\ ::,., ':' .-} .. ~ t ~. -",~,,'l~~' : ....... ,~ • .. . t .. r'~· \' .•. {.-.1 ' r.. 'fdfi!' ~~ ... t'\-';::"" '. i ,:. :'~"; ~~.'" ~~~~t. '.r: ~..'c

I"'tir' ....... ""l.." ,...... 1 ....... , ~ .f'O\..,tIi; r·- ·r "t':4--("-'" .,.t..;_ --.rt i_....-:~"'W· ::~." • rzg: ..... ~ Al cw .... J- •

SAMPLE -140J


-w -.)

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Plate: 4

SAMPLE -156J

(400X) I Plate: 5 (1 aoaX) I Plata: 6

Fig. 4.8A Microstructure of a Fractured Samples Cr-Mo-V Steel Weld Min. PWHT for CVN test at -30°C for SAW 4

(1000X)

-w 00

• TCR ADVANCED ENGINEERING PVT. LTD., V ADODARA.

SAMPLE - 156J


MITW-IS6J-1200X-SN- TW

Fig No . 4.9 Microstmctures of a Fracture Sample Cr-Mo-V Steel Weld Mini. PWHT for CVN test at -30°C, For SAW 4.

139

The lower notch value of 22J samples microstructures show mixture of coarse

under tempered lower transformation products comprise of martensite and bainite

with carbides and ferrites. The grain structure is coarse indicating excessive weld

metal temperature and possibility of segregation at prior austenite grain

boundaries. (Ref. Fig. No.4.3A Plate I to 6)

The color metallography approach indicated the presence of segregation at the

prior austenite grain boundaries from where the transformations have occurred. It

helped in conforming the presence of coarse mixture of under tempered lower

transforming products of bainite and martensite. (Ref. Fig. No. 4.3B Plate 7 to 12).

Color identification: Pinkish and reddish shade is on bainite. bluish and greenish

is on martensite and white/yellowish/orange is on ferrite. The lower notch values

are interpreted due to coarse under tcmpered lowcr transformation products with

segregation at the grain boundaries.

4.4 Results of Scanning Electron Microscopy (SEM)

Fracture is the separation of a body into two pieces, usually under the

action of normal stresses. It is end result of a process involving the nucleation of

crack and their propagation trough the weld material. Fractures are called ductile

if visible plastic deformation precedes fracture. otherwise they are brittle. Brittle

fractures are usually sudden and often catastrophic.

Several factors influence the fracture behavior of a material. These include

the type of stress. temperature. the presence of internal and external material

defects (notches. inclusions etc.). microstructure of the material and

en vi ronment( 40].

4.4.1 1\ Iicrography.

Fracture of component mostly involves the growth of one or more cracks.

The moving cracks leave behind characteristic traces on the fracture surface

which gives an indication of the path taken by the cracks. Post facto examination

140

of the morphology of fracture surfaces is termed fractography. It gives valuable

clues as to the mechanism and nature of the fracture. The technique finds its

longest application in failure analysis. But it has also contributed greatly to the

solution of numerous problems concerning the behavior of the mateIial itself, the

components manufactured from it and the assessment of defects and damage.

Fractography carried out a low magnifications (up to SOX ) is called

Macrofractography[411. This it self gives a lot of information about the fracture

process. Further insight is gained by higher magnification examination of fracture

surfaces (microfractography). Due to the roughness of the fracture surface,

microfractograhy cannot be carned out with an optical microscope. In the early

days of microfractography, transmission electron microscopy of replicas taken

from the fracture surfaces was employed. The scanning electron microscope

(SEM) has now largely superseded the Replica technique due to its vastly simpler

specimen handling and operational ease, while at the same time offering

comparable resolution. SEM possesses also the unique advantage of zooming

from low magnification macrofractography to high magnification

microfractography without disturbing the specimen. In combination with surface

chemical analysis techniques, SEM is the most powerful tool for examination of

fracture surfaces. Magnification employed in SEM microfractography is of the

maximum order of 4,000 to SO,OOOX. The secondary electron imaging mode is

most commonly used. Little or no specimen preparation is required provided that

it is electrically conducted.

4.4.2 Microfractrographic Features of Fracture Mechanisms.

Fracture caused due to following reasons.

I. Mechanical stress.

2. Corrosion.

3. Heat

141

--------------_. -----

We are limiting to fracture caused by mechanical stress, remaining two are not in

the purview of our project. The micrographs can be further investigated by

different types of fracture due to mechanical stress. This can be further subdivided

into dimple fracture, cleavage fractures and fatigue fracturel9].

4.4.3 Dimple fractures.

Transcrystalline slip fracture show characteristic microcavities known as dimples

on the fracture surface. When fracture takes place under the normal stresses, the

dimples are arranged more or less equiaxially on small shear faces, with more

intensive plastic deformation. They can be distorted to one side. Inclusions may

be occasionally found at the root of the dimple[6].

4.4.4 Cleavage fractures.

Cleavage fractures are transcrystalline brittle fractures in which cracks propagate

along definite crystallographic planes, usually of low indices. Only in exceptional

cases does measurable plastic deformation precede cleavage fracture[ 16]. The

cleavage lines and steps form a characteristic river pattern on the fracture surface.

In local zones where cleavage occurs also along twin planes, tongues that project

out of or into the cleavage surface are formed. Microstmcture can greatly

influence the cleavage surface appearance, e.g., pearlite may transfer the

characteristic lamellar appearance to the fracture sUiface. Intergrown plate or

needle shaped arrangements like bainite and martensite produce cleavage also on

planes of high indices as also separation along the intergrown plates and needles.

Intergranular brittle fractures, usually the result of grain boundaries whose

cohesive strength is reduced by segregation of alloying elements or brittle

precipitates, show characteristically the exposed grain boundary surfaces of the

polyhedral crystallite[38].

4.4.5 Fatigue fractures.

The above general concept is helpful to interpret results of SEM micrographs. The

results are matched with the basic principle of dimple and cleavage fracture.

142

Scanning electron micrographs, obtained using back scattered electron imaging,

of the low and high impact toughness value samples are shown in SEM Figers.

The contrast obtained using such imaging is dependent on atomic number and

precipitates appear white against an essentially iron background[40]. The higher

impact toughness value sample, it can be seen that there is a complete absence of

less weight % of oxygen. However, extensive precipitation in the form of

inclusion is apparent on both the lath and prior austenite grain boundaries. In the

low toughness value samples, the precipitation is somewhat coarse and more

widely dispersed.

Fracture paths running III the direction of the local crack progression may be

observed. The paths may have considerable height differences with high ductility

fatigue fractures. Within the fracture paths, one can recognize fatigue striation

running parallel to each other. Occasionally the material may split along the

fatigue lines, resulting in secondary cracks. Fatigue striations are less prominent

in high strength materials. A one-to-one correspondence between the number of

fatigue striations and the number of fatigue cycles to failure is not established in

all cases.

Scanning electron microscopy of fractured specimen of higher notch toughness

values 186J,I66J, 185J of trial No. SAW I (Rcf. Fig. No. 4.10 B,D,F) and 128J,

132J of trial No. SAW-2 (Ref. Fig No. 4.12 A and 4.11 C, D) and 140J of trial

No. SAW-3 (Ref. Fig. No. 4.15 A) and 1401, 156J of trial No. SAW-4 (Ref. Fig.

No. 4.16 A and B), sample factographs show mix mode of fracture consisting of

typical ductile fracture with dimple or rock candy type structure and ductile

fracture with river pattern structure.

Similar fractured specimen of lower notch value 34J, 38J, and 44J of trial No.

SA W- I (Ref. Fig. No.4. lOA, C, and E) and 22J and 28J of trial No. SA W-2

(Ref. Fig. No. 4.1 I A-B, 4.12 B-C-D) and 9·U of trial No. SA W- 3 (Ref. Fig. No.

4. I 5 B-C-D) sample factographs show predominately cleavage mode and

143

quasi cleavage type brittle fracture, however in some region of brittle fracture with

dimple type structure is also visible.

All the lower notch value factographs show majority area with brittle type

fracture, while some spot can also be seen in to the factographs, which indicate

different type of inclusion or under tempered region. In the lower notch toughness

sample, a number of initiation sites could be located but it was not possible to

determine the primary site.

Fractured and polished specimen of lower notch value 22J (Ref. Fig. No. 4.11 A

B) and higher notch value 132J (Ref. Fig. No. 4.11 C-D) of trial No. SAW-2

correctly reveals the difference in carbides. The white area of higher notch

specimen of 132J shows the well-tempered carbides at grain boundary compare to

22J specimens. These samples were ultrasonically cleaned before scanmng

electron microscopy.

Similar comparison of factographs of trial No. SA W-I and trial No. SA W-2

samples of top weld and bottom weld (Ref. Fig. No. 4.10, 4.11, and 4.12) reveals

well tempered carbides in bottom weld factographs compared to top weld

factographs. The reason behind this is that bottom weld has better tempering

effect compared to top weld. The result of notch toughness value of bottom welds

of trial No. SA W-3 give consistent result, so further investigation was not

required. Fig. 4.14 Shows the facto graphs of sample 10J as welded (A W) of trial

No. SA W-2 tested at room temperature. All factographs of sample 10J reveal

different types of inclusion and untempered area. This indicates the PWHT

complex carbides.

The project work has been carried out on the failure of a fracture weld samples.

Here, extensive scanning electron microscopy characterization has been used in

order to find out the cause of the lower impact value sample failure. SEM

fractrography studies carried out on the failed sample at lower impact toughness

value reveal cleavage facets, which are characteristic features of brittle fracture,

144

Table No. 4.9 Results of Scanning Electron Microscopy (S.E.M.)

Fig. No.

4.10 A

4.10 B

4.10 C

4.10 D

4.10 E

4.10 F

4.11 A-B

4.11 C-D

4.12B-C-D

4.12 A

4.13 A-C-B

4.13 D-E-F

4.14 A to F

4.15 B-C-D

4.15 A

4.16 A

4.16 B

FS = Fractured surface

PS = Polished surface

A W = As weld condition

TW =Top Weld

BW = Bottom Weld

Trial No. SEM of samples of

Magnification X Notch toughness

SAW-l(B/w) 34J (FS) 3000

SAW-l (B/w) 186J(FS) 3000

SAW-l(T/w) 38J (FS) 1000

SAW-l (T/w) 166J (FS) 1000

SAW-l(B/w) 44J (FS) 1000

SAW-l(B/w) 185J (FS) 1000

SAW-2(T/w) 22J (FS) 900,1000

SAW-2(T/w) 132J (FS) 1000

SAW-2(B/w) 28J (FS) 250,1000,2500

SA W -2(B/w) 128J (FS) 1000

SAW-2(T/w) 22J (PS) 3000,4000,4000

SAW-2(T/w) 132J (PS) 3000,4000,4000

SAW -2(T/w) 10J (A W) 35,220,300,700,1000,1000

SAW-3(T/w) 94J(FS) 800,850,600

SAW-3(T/w) 140 J (FS) 1500

SA W-4 (TW) 140J (FS) 1500

SAW-4 (TW) 156 J (FS) 25

145

(A) 34J-3000X- BW (B) 186J-3000X- BW

(C) 38J-IOOOX- TW (D) 166J-IOOOX- TW

(E) 44.J-IOOOX- BW (F) 185J-IOOOX- HW

Fig.4.10 SEM image of a fractured samples of Cr-l\Io-V steel weld, minimum

I'WHT for CVN test at -18°C (SAW -1)

146

'.

(8) 22J-IOOOX- TW

(C) 132J-1000X- TW

Fig.4.11 SEM image of a fractured samples of Cr-l\Io-V steel weld, minimum

PWHT for CVN test at-30 DC (SA W -2)

147

(A) 128J-IOOOX- BW (B) 28J-2S0X- BW

(C) 28J-IOOOX- BW (D) 28J-2S00X- BW

Fig.4.12 SEl\l image of a fractured samples of Cr-l\lo-V steel weld, minimum

PWHT for CVN test at -30°C (SAW -2)

148

(A) 22J - 3000X - TW (B) 22J - 4000X - TW

(e) 22J - 4000X - TW (D) 132J-3000X - TW

(E) 132J-4000X - TW (F) 132J-4000X - TW

Fig.4.13 SEl\I image of a polished samples of er-l\Io-V steel weld, minimum

PWHT for eVN test at -30 0e (SAW -2)

149

(A) 10J -35X

(C) !OJ - 300X (D) 10J-700X

(E) 10J-IOOOX (F) 10J-IOOOX

Fig.4.14 SEM image of a fractured samples of Cr-Mo-V steel weld, as weld

condition for CVN test at _30°C (SA W -2)

150

(A) I40J-ISOOX - TW (B) 94J-800X - TW

qc? c- C- r{-

(C) 94J-SSOX - TW (D) 94J-600X - TW

Fig.4.IS SEM image of a fractured samples of Cr-Mo-V steel weld, minimum

PWHT for CVN test at -30°C (SA W -3)

151

(A) 140J-lSOOX - TW (8) lS6J-2SX - TW

FigA.16 SEM image of a fractured samples of Cr-Mo-V steel weld, minimum

PWIIT for CVN test at -30°C (SA W -4)

and dimples which are characteristic features of ductile fracture in high impact

toughness samples. In addition. some complex inclusions were also observed in

lower impact toughness value samples. The above investigation by using SEM

finally led to the conclusion that highly elongated inclusions which created voids

at the time of welding. resulted in the catastrophic failure of lower impact value

samples.

152

---------- --

4.5 Result of EDX Spectroscopy Analysis

As we have discussed about the EDAX analysis principle in chapter no-3. The

output of an EDX analysis is an EDX spectrum. The EDX spectrum is just a plot

of how frequently an X-ray is received for each energy level. An EDX spectrum

normally displays peaks corresponding to the energy levels for which the most X

rays had been received. Each of these peaks is unique to an atom, and therefore

corresponds to a single element. The higher a peak in a spectrum, the more

concentrated the element is in the specimen.

The fractured specimens of trial No. SAW-I and trial No. SA W-2 of lower notch

value was tested by EDX for elemental chemical analysis. The result of the same

is compiled in table No. 4.10. The elemental analysis between lower notch

toughness values samples and higher notch toughness values samples show the

clear indication of presence of inclusion. The lower notch toughness value sample

of 22J, 28J, 38J and 44J (Ref. Table No. 4.10) indicate presence of inclusion due

to higher weight percentage of oxygen, sulphur and silicon. The higher weight

percentage of oxygen, sulfur, and silicon in the weld form different types of

inclusion such as oxy-sulphide, manganese sulphide, manganese oxide, silicon

oxide and iron oxide.

The lower notch toughness value samples are a function of segregation of

impurities. The segregation of impurities to grain boundary and to cavity surface

can change the cavitations behavior. The segregation of impurity clearly observed

in 38J and 44J specimens. The other impurities such as Phosphors reveals in 44J

and 28J, Lead in 44J, Co in 28J (Ref. Table No.4. I 0)

The above analysis clearly shows that lower notch toughness value samples

contain higher weight percentage of oxygen and sulfur and other impurities,

which decrease the notch toughness of sample.

153

TABLE 4.10 RESULTS OF EDX

ELEMENT 38.1 38.1 38.1 38.1 166.1 44.1 44.1 44.1 185.1 28.1 28 J 128.1 22.1 22.1 132.1 132J 10.1 tOJ 10.1 10.1 A.W. A.W. A.W. A.W.

0 Ild9 31.8 24.48 7.09 . 10.7 12.71 - 59.5 24.83 8 .• 13 27.71 7.41 7.07 (..59 37.23 J( •. 25 31.95 19.28

Na - - - - - - - - 12.59 0.67 - 9.24 - - - 8.74 8047 - -2.75

~Ig - - - - . - - - - 1.87 - - 2.55 - - 3.36 1.57 16.67 1.17

AI - - - - - - - - 1.()9 0.38 - 1.51 - - - - - - 1.09

Si - - - - - - - - 2.73 - - 5.4 - 0.25 0048 .1.47 2.17 30.53 3.64 0.09

S 0.51 1.54 1.04 14.15 - J·VJ.1 8.69 2.95 - 9.16 - - 1.04 - - - 0.75 1.97 - 1.13

CI - - - - - - - 2.14 0.29 - 8.28 - 9.2 5.71 - 4.06 0.98 11.04

K - - - - - - - - - 1.52 - - 1.55 - - 2.6 2.49 - 1.4

Ca - - - - - - - - 3.97 - - 2.05 - - - 2.82 1.83 - 1.06 1.05

Fe 69.52 63.88 68.97 61.65 85044 34.91 76.1 94.14 nA3 .UU 68_19 87.89 40.67 90.71 88.64 87.81 31.54 37.83 20.85 59.89

Cr 2.77 4.45 2.27 5.65 2 .• 12 2.88 2.7.1 - 2.03 2.63 - 1.88 2.29 2.27 - 1.71 - U8 1.83

I\ln - - - - - U,S] 1.15 - - 1.17 1031) - - - -1.95 1.06

~Io - - - - - - - - 2.42 - - - 1.18 1.47 - - - -6.1 3.15

I' 0.08 I - - - - - - - - - - - - - - - -

0.07 0.03 C 11.67 - - - - - - - - - - - - - - - - - -

10.87 V - - - - - - - - - - - - - - - - - -

0.86 0.55 Ph - - - - - - - - - - - - - -

8.59 Co - - - - - - - - - - - - - - - - -

0.46

IS.VI

Table No. 4.11 Elemental Analysis of fractured samples by EDX

Joule Value Sr. No. Trail No. Position

Sample

1 SAW -1 38J (TIW) Inclusion

2 SAW -1 38 J (TIW) Inclusion

3 SAW -1 38 J(TIW) Inclusion

4 SAW -1 38J (T/W) Inclusion

5 SAW-l 166 J (T/W) Random

6 SAW-l 44 J (BIW) Inclusion

7 SAW-l 44J (BIW) Inclusion

8 SAW-l 44J (BIW) Inclusion

9 SAW -1 185 J (BIW) Random

10 SAW-2 28 J (BIW) Inclusion

11 SAW-2 28 J (BIW) Inclusion

12 SAW-2 128 J (BIW) Random

13 SAW-2 22 J (TIW) Inclusion

14 SAW-2 22J (TIW) Inclusion

15 SAW-2 132 J (T/W) Random

16 SAW -2/A 10 J (AS WELD) Inclusion




154

Spectrum processing: No peaks omitted

Processing option: All clements analyzed (NormaliseJ) Number Dr iterations =..J.

S\allJarJ : C CaCO.1 I-Jun-1999 12:00 AM o Si02 I-Jun-1999 12:00 AM P GaP 1-Jun-1999 12:00 AM S FeS2 I-Jun-1999 12:00 AM Cr Cr 1-Jun-1999 12:00 AM Fe Fe I-Jun-1999 12:00 AM

Element Weighl(J!" AlOmic%

CK 11.67 29.48 OK 16.39 31.10 PK 0.08 0.08 SK 0.51 0.48 Cr K 1.83 1.07 Fe K 69.52 37.78

TO!:lls 100.00

Comment: ,Xj GDM! T4 EDS line spectrum

Fig. 4.17 EDS Analysis for 38.J Top Weld SAW - 1

.... z i'~.;' 31": ....... , f"t'%*i*'u"S=¥'- 'iitJW ~.- *+ «) .~ .~.{' J c;.,.. \""i :i'.t 0'»0 \ .. ~ I' • .,..~ ~_ ~ '4~ ~~'~,... l' ~ ","' • l' .......... -. ~ nfl:.,:.:, •• -",,- "<>'-. '~~ ..... l ... , .. ~ rJr-~,~~"'" ~-.. : c"l-l-.\; ~-~ .... "\'\ ._\. :;,.< "',

,r. 1.' <1,1 .... • - -t<~'\ ',:>I ...... "'-_ ·C .--- • >..- ,"" .' 0" •

~.... I "I#' ":i:.. ',"",""'''''''- ".". u ;....""'~~ ,,',

~ ___ .F"'''''',*~.' . -. ~ ~ . _ "' .. " , -IlI';'~... ,;0- "'" .~

. J '. ". ,..... .. t. - - ,i'· " ':t' • ; . ~\' ,. ..... , ..... 'f' " --... 't.. '1. .... ~ I 1I

~y_... .,i ~ . ~ ,'c ,... _~ I .;".. j 1("('1 "til; '\".:~ .. ~ • oj. ,fIIl." > .. ~ .... v~',~, , "Ii-, ... 1-

f .. '-.~ ...... ' «" ~, '"..,j ~ * J~\."'"4.~~;:'- ~~~'t}1 ~ -1' '"-..~" ~~t -1 1 v .... "\,A "I •. i~~i'..r: '~~' ..... : ~ '::_ ,- , .. ~ ... ,'~; \' " .. '1 'N . ..-.... l>c' ....... , ",. '>"~ ,,""~ /..d, - _.

' .. " '\ "-~.'" ~,~, '" ... ::-: ~t-- l' 11'f'/:., 'tt,~,.~ ~ ~",jI"rt-::_,,-t, \, ..... ~ ;fe" \ ].~, .' f'l\"? >-A':;tt: ~f''''~~

rl, _ ...... ~·...:t ,}. '\ :. '. . . t, I./: ., --.. , " 'I"'''' _ ~ .... ,~.,,,) .[-'-- ,,-~~.~". ," ... \-....:

t·:"'··' ~)-" .. , ""'-'.:. ~,; ~'1. ""{"~"'.-:;'~'. \" 'W c"'-' .... "!I'."'-"" . r:.~, 1',' "',110" •

,.J " "h".( f,(",,·.~. 'I.) . ., I .......... , -" ,.,'. /I' ... ~".

~ ....... - '. ,. ~'-~ .... ~ . I'" ",,'. . ... ' ., .... "}i' ...... t-~. •• w .' • ,.... _ .. > L , • ,"' .' "1/(,,""' .. ".. ~ ....... ,"!:, 't .. ' , • .... -t .~ yo'." , v, ' .... ~ .,'.....'\. -,.k I "- " ~ , .-~""'--"'~'"'h'-':'~''''''' .'f; .... .". ~"" '. 1,·,,/,,1:-fn" ''''L''1.~''''~'~f-:t'''.\;''. f' ..... «.,. .~,'~.. ,,,'.''i., ...... ; " l;~( ... t~ ~." ", ... ~"t ~I.l~",~' .. ,I "~;""~ 4,," ¥.'~~" + -:",-.~ ","'~ !., ... ..,.,#, ... ~ .. \t.." ....... .,I ....... ~ "'i';""")""" ~ ...... , :ot .'t •• ~.... ¥ . . "'~,c .. ~~ .. " ¥tlC':-"L ,"Ji; " .', _ ~'" • - ,'", , , •• , .... ~ . .,.,-. .~ ... ",~"'T-\,~~ •.. ,.~." , ..... " .. "" .~' "'.' ~:...~ '-07' """w ......... ~v .4.. .... ~," ~~." ... ~'e ... ~II.' ,:\ .,.V' '-.: .... ""-,'" _ .... ,:--._ "- .1'_ .. f' '"'IIi.." . .... ... ~ . ," .. < 10- '

! t~"'" - - • --..: ~.~ ..,.., • ;-..t.' ~ 0 '<;.. .. j r § --to

• ...- ..,. ... ~..:.Ji-. .... ( ... ~ .. '~~ii.~V#\"~:"'..,. .. _l""':._ ~,'~ ~~,,:., ... ;'#f<'\: ~~J', i.~ •. .,.",.,,; l~t ... ..:t"'---"': ......... ~., .• ~ .... ~~'s.. ~-.. .. , '!I' - _ '.l' ",11; f."IIII.A.' ...... ,O: ..... -lI·.,- ..... ··~~· ",.,,"~ ..... '. ( ... 4, .'-. • ..("'\, .......... ~ '-.,. .... .1: ,M. ,~" t .. , ,,' -",""/ jJd1J~ )r..'1t ...... ~.t1..~.;.: !r;':;:t.. ...... ""..",~~_...:..,.

60~m Electron Image 1

Inca, 55

EAthhrya 29 .l2.06'4c~":\i,;,'t,:'"0" 29/1212006 ISSS:20 ~~:~:a.:;'':'~ ,,~.:, ~. ,;_ ;,~~,:~il\':_:~" <·-!~,}g~·_~l.~:·',,'·i':',~rf:l~:;~~~';;fr~:

Spectrum processing: Peak possihly omineJ : 3.6-1.0 keY

Processing option: All dements analyzed (Normalised) Number of iterations = J

Standard: o Si02 I·Jun·199912:00AM S FeS2 I-Jun-1999 12:00 AM Cr Cr I-Jun-199912:ooAM Fe Fe I-Jun-1999 12:0!) A~l

Element Wcight(J Atomic%

OK 31.~O 61.-I~

SK 1.54 1.49 Cr K 2,77 1.65 Fe K 63,H~ 35,38

Totnls IO(UXl

Commenl: :181 GDMI T4 EDS on confined arca

Fig. 4.18 EDS Analysis for 38J Top Weld SAW - 1

F" -· "' .,4 .,Or • • _00 a,A • '2 ... -. , . ,~

i r' , 1 . ,

, ." ... , , '. ", , . Il. l: ..., ',. ~ A"',;,,, ,... ·'C;'

~~~".....,~

f''''J!'· .. ·... I· ',,'" ~ '" ..." . -" " I . 1 ~.. \. A,,' If . ,.<"'. ,;'.

\ "'4" ~.,. ~) , .\ i' ->

~ y 1: ,",' ,.. ~ ~, . ': '. , 'r ;, "1 '.,' r " _

>. ~ i,>~, ..... ! h ....-~f:~D~:t ...:--~ _~,,:,,~j .. t!'

[

" .... ~ .. t~ . ':', "",,-:;:' '--., .. _ ,.

" -' I 't·· ~'""' ",. ...... •• # ,

t~ ~;. >~ .. ' r/.' .... J' Ll~~ ·c _ .......l,L~ ___ , h '_ -......... -.;

..~

-.

- ", . .,

i

'"~ .. 'j ~.- .......... ~--~ 30l-lm I Eler,.; .. ~ .• " .. ~,.~ ,

Inca 56

~Acharya 29.12.06 i"~,1'J;~:" .. , .. ,,;,:;.,,>,. 29/121200616002< ~~n""~~--.;v:,o~'-'~~'· _";"~1'-.(~,,,,'f1~'~,:;-,~~\'j:: ~\'~,~\:-:l:;{': \?>:;·Ihf';'l'';~ :).¥~. ~.:- :'


Processing option: All elements analyzed (Normalised) NUlllhcr of iterations = 1

Standard: o Si02 1-1un-1999 12:00 AM P GaP 1-1un-1999 12:00 AM S FeS2 1-1un-1999 12:00 AM C1 KCI 1-1ul1-1999 12:00 AM Cr Cr 1-1un-1999 12:00 AM Fe Fe 1-1un-1999 12:00 AM

Ekmcnt Weight(/p Alomic(jp

OK 24.48 52.52 PK 0.07 0.08 SK 1.04 1.12 CIK 0.98 0.95 CrK 4.45 2.94 Fe K M1.97 42.19

TO[~11s 100.00

Comment: 3HJ GDMI T4 EDS on confined arca 2

Fig. 4.19 EDS Analysis for 38J Top Weld SAW - 1

r"'-}-<'!-:;~'t t4c"'.~: .~ .. /. :'~:- .•. ";""" A ...".~ .. :.: .. " ..• ; .•. ;.~-".. ... ~.' ....... '.'-. -". -." ~~) I '_~ :t'"/;"~,,.. .- ..... -.-,.'.--:_~.(O:"':X.""'J- ....

_ ,_ ._ ~ ./.:_ .. ,~_ • ..-!.. ,.~~ .\.... .. .. ;'3 . ."r.: -~, .......... ~'·· ... _f #~ --I!""""" ................. -... "" ....... --~ .--

. t-"';'~' ott . .,. .. ~ ~.l. o/..t'; .~ ',~", ....... - > .." ~ /.:,~, .. t4'.- ..... ,.: ~'~~. """ ¥ V ... . ~ ~~ ", ... ? .. ' . I .' ~ -" .-,- , -", _ .. , ... ~~ J" .r', -:.#. \.\..'.,! ..... ~_T¥.,.·f~' ,\, .. 4"f-\~"' •• u.~ A"" . , .... ' ,~-~,:,:" -',. ~

, _ .. C " <t P. "i -. ,-,','" ',,- ",

J. ~ ~ <'1 .. ,..... ~ ,..,.-CO,' ""'-""Jt >,"'. '..1," ':. ~ <. , 'le' '" .'(:( Co"' I ~_:/.,\ 5.C"'''ft-:~¥J ~',_~',:''', ." "/: ',::, - _ .. ' ':~," .. ~~.-~~~,:,"':"~." -\-';t ,<"J' <,~:~ " \,;.t 1"1 _ '''' ..• ,', di-> ,r,· '. <,:,.::', '"·rt, 'i'e" .. ,),"<.:'",. ~:,.:. ~~,~ 'I' .',/-::' 'if:~:~: ~'; , ,._, _~ <;,rr-", ,<;>""'~" ~ ,:.,~ _;;~:;' .. <-"i ,t

!i'H-\ .,""f'\~'<i.~ .• r'. If t, -t~~.: . .... .;. ' .. " ~ri-. '/" ~

~l:J·-·'rf~~'-r~ ~,(~ ~ ~~ ... ,,;. . .;' "~'-I' 'r-~; c .. '.A"··'::' '.. . '; '-vi~~"~'" -;, '"; ,' .... "

\!~~3;:~1~~~i~:">" '-~, ~(J . .. .... ; ",,~_,<,,:"'.A~ .. fi~<.'" ;:'~.' ;~.,._: t. ,_ " ~ ~" t''''' --" /. ~ "" ", ,._~u :..... .& ...... '-. • ..:>' .... ;,,' ".I, .... .-.~~. i- , . " ' , "" • .:..--=

~~.'.':.. ~~,,,,:y..," '~'.; r ,:. •.. : -.c····.: .... j 11.; r'_. __ ~ ,. :..~~,~,~ ........ --"-""'--'-'~\ t ;1""'1' ,. ," ... -'" ___ , .. '!Y.-

"

40~m Electron Image 1

Inca 57

~~~~rY~:2;,},tR~ ~{}li:ji~,:~~;~~,:;) ;, ;,;:;;1t~~;, :~. f ., ~'i .: ,;~V¥~!;~~~~i&f '" Spectrum processing: Peak possihly omitted: 1.765 keY

Processing option: All elements analyzed (Normalised) Number of iterations = 2

Standard: o Si02 1·)u[]·1999 12:00 AM Na Albite I·)un, 1999 12:00 AM S FeS2 1·)u[]·1999 12:00 AM CI KCI 1·)u[]·1999 12:00 AM en Wollastonite I~Jun~1999 12:00 AM Cr Cr 1·)un·199912:00AM Fe Fe 1·)u[]·1999 12:00 AM

Element I Wdght(h Alllmidl,.,

OK 7.09 17.80 Na K 2.75 4.81 SK 14.15 17.73 CIK 11.04 12.51 ClI K LOS LOS Cr K 2.27 1.76 Fe K 61.65 44.34

Totals 100.00

C0l11l11cnl:38J GDMI T4 EDS on purtieul

Fig. 4.20 EDS Analysis for 38J Top Weld SA W - 1

Electron Image 1

3601 cts Cursor: 0,000

•• " IIIC!J 58

;iAcharya 29.12.06 .. ~,.;j,:r., 2""212006'616 •. 17 ,:!;..;'"';V'" . • ,~ .,.~."t"')~~"''- ".'., .1


Processing option: All ckments analyzeu (Normalised) Numher or iterations::;: .3

Standard: V V I-Jun·\ <.J9() 12:00 A~1 Cr Cr \-Jun-\999 \2:00 AM ~tn Mn \-Jun-\999\2:00AM Fe Fe \-Jun-\999 \2:00 AM ~\o Mo \-Jun-\999\2:00A\t

Element Wcight% AtoJ11ic%

YK O,S6 0,96 Cr K 5,65 6,\9 MnK 1.95 2.02 Fe K R5,4-I 87,20 MoL 6,\ II 3,63

Totals \IX1.fKl

Comment: 166 J GDMI T5 general EDS]

Fig. 4.21 EDS Analysis for 166.J Top Weld SAW - 1

-.. ".; ;:w~= ~: ": < "~·H~<;C. ,U;-:V*;:";;' \. • .. "'t-.~ ;.! ~; '['7': ~",.;c!?~v~"'--f',-'1 ,\ ... ~ .-.'......... I~ ..... -,.;;-.1 I ~.. '.I. "..It' .... ~ ,_ .. ~'f.,,' cf!:..... <.,_ '~~ _,...... " • _ ......... _..- ~.,.. f ' r- , .. ''''''' I-~ ~ ..... •• .. "" , ;.It-- ··,,-,"-":·~r·_":t. .~ .. "': ..... ,"\',' c~\~~; ..... 'i ,>~.~.- .. ~fti!:, to' '_ .. f"

'. :'.fl~ -'-C", • .,.. _~J'",: • I ,r \ ", "'"~' ,,-;"1 ' ,::} .' ";I! ..... ~. ,.: ....... v-I ,'4 '4 "r .... " .... Io', f",'f"~l-.. -~, _--'r .... ~" t·~f" .. ,.\j~ .. 'llao-; ... 'I:". '~'~-. '.~~ ,;"," '~'~~..i , .... ,.".,,:.~f-:.; ':'":. ;\.:;

~ •• , ,!r'i' "...~-_ .. 'iS" /'_ '1' "';:'",:",.';':. __ ~,,_ :':;'.:"'~~, , • . j..... ~, :. ..• "":r' ..... " ... ,,-.r. ~ .,l! ... f ~'(, .. ~. ,,-. ','l.'.... ~ ~'~ _ i "',,,, ~. ,~ ....... ,I#IO -:'''I,!. "" _('.,';;":Ii jt.' f~~;'F' ~"t...~ _' . ~ ..

" .. '.~: .:".:.: ".: '~11!""-. 'r "', .. /.,. ...... ~,~"".-...... ~'~."...of" ,_-''''',.. ' ~ "', , - ."...-. J;, 1OJ~·..r."J1-~ " ~, .. ~I'''-' _ '''" "~j

[.

~f_",:f' '; .......... ~~~.:"{ll \.. __ ,: '~' •. _ ',-: . ..1"1.':;";- '_ "" .. .,._....... ' \. . 'v " \ ........ ,., ...... ,f! ", _. .. ,_ _ , . _ " • ' .~, ··'·".(~'~~·"·-;··'~:r~~tr ,.~~. '''';i~-:'', . ;:;A'" .... _""' .. j' ~. ' ,. _ -... Ii-:;.,._'JI>"'- ... ~., ..... ~,.~ __ ._~~----:: _ ""~-"';"'" ._,!4-t,..~ .. _ ... -..,,_ .. , .. ; .... _, ,," ~ \1 .. __ '_" ""'.~.. • lit, .,.. '.-- ~' ... "" ~ __ ....,

I' '. -"', "'{"C- ";'il .•.. ~- •. -' .. '/' '>~·""r ~:'"i;·.;:;":;'~1"~,-~-:: '.;:~~" ' , '"'::':.>i:'~;,1 +"':: - to.,' ;- ~ ,~"~:~,,, '-'-"'- 0.;,#o~' 1~',,~, - • - -,_"" ,_ :':'7':,."t 11,-,:.-,1:. ~:,.;~;,7.!"--4'·~..r-.;,._;--.::..;,w __ "'--'"'·"" \ .. :-" f'.'t .... -;,,''''',.,:' ~l

~' . '_. ' .... , .. - ... , . " •...• J '" '!fI' .... " ~;r ........ 1P't' "'. "" F _. ~ , .,t, " . • ,J ~,; "',," -1 .;;..~,,:~:.:~-~ •. ' .,;. ....... ''"'" ,.<.; ~ "!",~~~.,,..~ .. ~""~~ '",.!;.~; .""-~\.~ .. ..;~;. - "~J 'J'" r 'r-q,' '('''' ~. H " ... '" ... ..-"" • ....., - l- 1 __ '" ~. ;:y'.' , 'ill ;i~~;'·· ~: •. f.;:":.." "':', " :f~': ''':-.. \:' "-':~~;;";,.1":.:.:~:j

r· · '- '''' . ..- .. ~''- '~, '~"\ .':"7 "- ' -' ,:.-T" "~I -<of "' .... -, --'.... • l' .J,'- '~-"";;r: l'-'::$'

."'...,. ';. "',"'.n ','-' ('. ~ - 1 (: -1..;;;-,:.:: ' •• J ... IiS:.?'.r"~'~¥'\-'f:t'J

i ,:',::'.t,l '. ~'.~"'" w. \ ,.' -':.···o,:·~,~~' .. :··~~.....,tlt.~ 'i~ -,." .'_' -' :. :''';~ , ""'>'"X" i"-:~6-~'~- ~V;--~~;"'''1

' ~., -.; .... ' <' ..... '.! . ":.' " .. ~ "..~~.,.,.-/ ""-""";,.:11,·,,,. . II! '~'1J" • ,£', '.-~ ~ - '(I-:~~ .... ~'!""". :.. ''"j''' .;J,../'t':,,~"'.' __ ~:=''' .• ~:, _ t ... : -,~. c.;«r;!:1I'~._-. ... -:r_" .. ~" .. ~.;,~ .. !-:r_~' __ r(.;~''(.~ ~.' '''':l:~'~·~\~'".L,_,· .. _ "'..da.a.J' _____ ... :.:

_d:a..... . -~ Electron Image 1 40IJm

Inca 59

, c' ',- "~.",-. ".'.' -;,_'. :,' (~~11' .... -i' Acharya 29 .12.06 ~}tfK1il~",.. '. ,,< i~:";'~[(~~;' . r' ,,'i;'~~~~~(~,;, ~I.~.t:'!',~ • .:i. ."-::,,,-: '._'tH ''':'-:' ·,~~,~"'\iI9(i?'~"h:..i'J.\ ;1' " - .: . '." .,;' I


Processing option: All clements analyzed (Normalised) l"umhcr of itera[ions = 3

St,muarJ : C CaCm I-Jun-1999 12:00 AM o SiD2 J-Jun-J999 12:00 AM S FeS2 I-Jun-199912:00AM Fe Fe I-Jun-1999 12:00 AM Ph PhF2 I-Jun-1999 12:00 AM

Element \Vcighl(i~ AlOmi\..,I/(,

CK 10.87 27.19 OK 10.70 20.0R SK 34.93 32.72 Fe K 34.91 IR.77 Ph M 8.59 1.25

Totals 100.00

COlTImcnt:441 EDS on confined area

Fig. 4.22 EDS Analysis for 44J Bottom Weld SAW· 1

[~l> - ~5~r~T'J?"~::-~"~~ '\.v-)\~~~ ~T'""~ ~i;;---"'t""""_;,.'¥~t;~~ t "'1 -. ~:." ~'. ~.".:_ ...... :';!' \."~- .. ' -;0, Ii. ~". ~ ~' ...... ;)}., i'j;. .~

, .,l(.~::t ...... -_ ... ,\.;;. ....... ,', '.""P./. ,) ... \-'I;'\..;' ,~.~, -io" -· .. ·..,.:~:-'· ...... J'l· 'l't-' ',~ '''''-' .. - '~~-",,,,,,. '~""..:;,e"'" '4; ~'. 'j{ '~.:- 'l\ '$J~ , ... ~. , ;-'~)..I:', ,.L.or' ••. :: ..... ;.. ~-.:II~ ~ "~'~ ii,._ ....... ~~·A sit .~if: .. ~ "t t;.}.,~; ~ -:; ... ~~----, "-_} ,,)}--: ~,

~;'o'!t-~';''''' ~* • "1"'" ~ .. 11 t .,.: J '. 1,.' '", ...... ~.~ :....;

.,' .,.~ .. ' • 04 ':ft-. l' !~> " .... IJ~~" ~ • 1 ,..... ~~.1 •• ~ ..... '\' ~ ';.. .. '."~ ... -"~'r:)'~:>'<t,~ ........ r.-'·.t.' . I..' .. ,~ " -'~'--' ~,. • ~~ .. --.:' \,.. . ,. ", ,..lI- S ~. _ ~"'" '4 '-!o. ...... ~\' -,,, • ,I.>~' "')- '\~.,.. .... ~ .. ,.' ,I' ~''''''' ,;"f-:. ' ~ "\'"';r~" ",,1,'!: .-£.-~ ..... ~~ J;J. "F_:"> ... ;..";1-.t '.' ~"'f.~._"" .. , ...... t' .. 'Ar "", ••• ,.,., _,_.' •• , ~ (~~."",,,,,,.y.-9~" ~' .~'r"""" ~ 1.£0_ .. l'" 'i ~~ '~-':""I.."" '1M

~\\)~::"~~':'~U'/'':'C~I[''":'~h-'-'~)I-';;;'''~ ,'-:\. .... "~'; ~~~, 'I' , .•• , ;.:~ .... l.c>""4'" -W:1·.,1 > .. _ ,', "1 -":-\,~~ ... '.o( - ''/'-" .~

"'(-.'" ..... , .. ~ . , "": ',,'" \~>;- ... , - ;.\ ... .,<-' '',.-; ,;~

, ... f ~ •• ), ..... ~I 7 ....... f ~ ~.J',.~ I jf •• ~.",.. ~}'~XI'; '.

't'1 .. --'< ",rf~·'''''_~-J'''''''' .~. 1 . ",," ... --.,.~, _.'. ~l. • ~,. '-<! I'~ ~ ...... ', -.I. } ...... ~ ~ .. ~ '~"'''''.

,'.-' -fc....,,·,OO .... , ....... ,-.., •• , ,'--."t .. ,' .... '·'-1 ... ,., ... \~....." . ~_H' 1.0.0.......... -'" .. ~., ,.-<. ~~~'!..rd~ .. ~ . .;~ ',,"'7-"~\""'1"1'~ ___ ".~ ... ' , ..... ,;..t.l- ···! ...... t' , • ~v. ~.~' ''''';';:'Jw-~:'' 'Y., !II .- .~..,,'IoI" .:::..~ 'I'-Y'" '" ~ ~~:.J~"''''~.;!6i... .. '':. ..... '':.':~ , I,.i"·~ ... ~' ~J~"./"- .:,"'-..::'..,~!r': .. ~,....",..

~ r"',-4 ~~-;1)'-(;~' /. ~t ~_~: ............. f _,~ - ,--...... .......-! '1~~",(~~~ ."'.1 ',r- .I" ,,\,~ .. ' -~,.~. • ,. ~>- ~ .. - • ..;~ _~ "!,,," _ -j! r. "" ... ~ -, .. ,.. ,- " '.''''_ =--c-.......... . . ' ,.,...c ..... " . ., -~ r ~ , • ,< ,,~, """,,,

I' ~'~l~." ... :."'. .... ....~, ~ Iff.;'" !...., "'-"' , tl~ ~.~"!l.-..,f#j,;"'./,.:!"'.i?"; ;l~,t.~ i,~~"'~"V'f;: .. ;,.}.f ;.; ..,;,i' ";l- • r. ,~~ '1"'. .... 4.. .. •. _ '" ,..." -. . 1·,·, ' , .. ~ - ~"". ... -~","I" • ~. "'.\ _I'-!;)'~' ':f'l- ........ ,-... t.~ ~ .... - .... .-:: ..... ~ i { ~

r\1'.\-\., -,-Yt" .:.:- ~- It ~ " ~""".\. ! !-Y". ~ .t t • ~ ",' ~ ~. ... .. ~ -...... -.' it !~'LN" 'A". '.' '~:- .... ' _:"'lr" ..,.r"';:....., .. - ". ';:!,~L;-" *_.t~!Z: ~ ',:~;..,~-'I' ~ " ·~2..,;~ .. ~'t; ,- I

404Jm -I Electron lmege 1

Inca 60

Spectrum processing: Peak possibly omiHed : 1.479 keY

Processing option: All clements .malyzed (Normalised) Numoer or itcrations = 3

SlanLlan..l : o Si02 I-Jun-1999 12:00 AM P GnP I-Jul1-1999 12:00 AM S FeS2 I-Jun-1999 12:00 AM Cr Cr I-Jun-1999 12:00 AM Fe Fe I-Jun-199912:00AM

Elemcnt WcighlCJ(' AtomicQ(l

OK 12.71 32.06 PK O.IR 0.23 SK 8.69 10.94 Cr K 2.32 1.80 Fe K 76.10 54.98

Totals 100.00

-----

Comment:44J EDS on confined area 2

Fig. 4.23 EDS Analysis for 44J Bottom Weld SAW - 1

:;C;,-- "-,~~~~-:{~"+::..,_.'-'~ ~~~:;~~~j "> ~\ ,-""". ~ , .' ~'~ il~~' ,1 -..... ~ ~ . ,.:,1,," _ . v :._~. ~~~: ..... ~..,( ~ "" ,"~.~

'. ..~~." :;;:'~~L <'_~> 7~ . '/'~:':~~:;~~~';'~~\." ~"~~_~:~ :~ ... ~~"~~ j.~" .'\.. • ... ;;, ... ; \ ... ,. " :".~ .. ::,\.,~: .4'''t'''~, '.,':: •. ,e..,. .' 1

;:.:-." ·.:h~ .:~

: .• ..; ;.;,.. ~"~~., ..

r.·~ ;.::!.=;;.~ " c,. ·-;~';Jr·~.~~~l "'>-': _.,::~.:r .. ,::,.". ~,: ··-·'~1("' .. II ' "" : : .. ::-j ~ • , ...... "lJo.~ . ,;3.' '~i'.f' "1 t ~' ~ ~ :;'!1';~~!::' ".,,\\\;~ .. -::);. . .. <. cI"~' ""

:',~.' ~.!-'.,'J. J";.";"~")' " ,:~~y.":)v·':4. .. 'n,\ .... "';O=~""',".-"'{·"~ ",,,,~,,~ ·""~·l·'!tj~-"·f.'j/"'~~, ",,,-'.' .--:',,'" '~'f.,:".'"!');..""""" '.'/ ...... , "l""'i ?·:;~:~t~I:j.~.~,~.-;{:~ ~;; ':; .~~.),;;:~~(l \ 'i.~~'. "f,~>~~?t··~·· "~:~~~~'~:;:' ~.~~

11.,,"1it.:,~ .. '·':· '.~~,,'~,.:-'1t.', "k'M.\tHb,1 .'\' .. ' " .. ," I,' ~,'" ~\tt, ':. r...5~x.5~:. :,·,·"'·:~:"'J1· ," '~' .. ".i""'" ,~ .. '., ,'''~.t1 rl:.~,~;:,:",;.~f;'··;;i.~·· .. ';..;. ,,,.;,~. ~,. ~,f'.}! ; .. "\ . .f '-: ' .. t', ": .,,:1~t.'i.' \"".1 .... :,. t. :~";~1

... ",.}/..r~,,'. '.,." '.<., -V" "1:"" ... ~""" ...... ... '1 ',. ' .. ~ '.' " ...... ,... '! ~r', -\\ .... ' ~ ,'\ 'L"'1

" ~~~i\r,~~:~';~,,;:-:~'-~~" {.: ~ ';1 \ftifq:):~~:l ."' .... " ... ",' . ". 'c.Ji ·""'.11. '. -'~""'·V ,y h.·, ~

~",. ::!,

''.I~.* {~\~~/ r. :"', ''''~-~y''i' o.':;-"'",:"'C'''. " ·· ... ~1fII;::~;v.G.:,· >c.,;.'.P ...... 7,.' .. "'· <>'.",':~ .. , '

" ... f"'if .... ".~.~ .. , . .j~'''''''''' ,<~":<'*''i'~' .t ~;.,- :,',\,' ... , .. ,... •• ~+~ .. ~

< '7Lffl~i':~'~c,*;~;Jt;~~!~~ . 6th . gCet 7&<;. .• ·",·.. ;.,~I.;'~f ........ ~:... b' 4,...i~~

L I'.ft:· .. '....<'

40jJm .. ,cctron Image 1

Inca 61

Acharya 29.12.06


Processing 0Plion : All clements analyzed (Normaiilocd) Numhcr of iterations = :2

Standard: P GaP I-Jun-1999 12:00 AM S FcS2 1-Jun-1999 12:00 AM Cr Cr 1-Juo-1999 12:00 AM Fc Fe 1-Juo-1999 12:00 AM

Element Wdghtlfc Atomic%

PK 0,03 0.06 SK 2.95 5.01 Cr K 2.X8 3.02 Fe K 94.14 91.91

Totals 100.00

Commeol:44J EDS 00 crack ~


t

~.,

-, .....

.';'" ;ii., ~~"

.,;:.'" -;-,,~"<~'/'t-·- l !

" ,.. # ,A.,

.•• Ii'-

. I. J:, :;~".!1f :".

""" . .-~ , '. f-.. ./ ",,'.

~-~ ,'- .' 1'> '! 'f . ,::' -"-, '~', '~-. <.~ ;r .. ' ~ ~ 'Ib, J ... , - • •

:., : ", '1:"

" ~ ;'

'~" .. ,.j

1":~ ~1i~L~.. . . "~i" ~ .t. ;/) ~1, ,( _~"~' _~.'j~; ~\;~7'~,..~~ ,'.-~:~-ii ,,:,.!f-,o·,·,-!}.,~, .. :Y'~::J~ .. ;;,:

!~~~·':·~,£;'~i/(~" ~,L;"::·(~d JO"m i FIPrlmn Imaoe 1

Inca 62


Processing option: All elements analyzed (Normalised) Numhcr or iterations = 2

Stanuaru: Si Si02 I-Jul1-1999 12:00 AM Y Y I-Jul1-1999 12:00 AM Cr Cr I-Jun-1999 12:00 AM Mn Mn I-Jul1-1999 12:00 AM Fe Fe I-Jun-199912:00AM Mo Mo I-Jun-1999 12:00 AM

ElemenL Weight(}(, AlOmic%

Si K 0.09 0.18 YK 0.55 0.60 Cr K 2.73 2.96 MnK 1.06 1.09 Fe K 92.43 93 . .12 MoL .1.15 1.85

Totals I 00.00

[ c:omment: 185 J general EDS


.--- 40l1m Electron Imege 1

Inca 63


Processing: option: All clements analyzed (Normalised) NUlllhcr of iterations;: 4

Standard: o Si02 I-Jul1-1999 12:00 AM Na Albite I-Jul1-1999 12:00 AM Mg MgO I-Jul1-1999 12:00 AM AI AI2W I-Jul1-1999 12:00 AM Si Si02 I-Jul1-1999 12:00 AM S FcS2 I-JlIl1-1999 12:!X) AM CI KCI I-JlIl1-1999 12:00 AM K MAD-IO Feldspar I-JlIl1-1999 12:00 AM Ca Wol1astonite J-Jun-J999 12:00 AM Fe Fe I-Jul1-1999 12:00 AM

Elemem Weight% Atomic%

OK 59.50 73.29 Na K 12.59 10.80 MgK 1.87 1.52 AI K 1.69 1.23 Si K 2.73 1.92 SK 9.16 5.63 CIK 2.14 1.19 KK 1.52 0.76 Cn K 3.97 1.95 Fe K 4.H2 1.70

Totals 100.!X)

Comment: 28 inclusions in the Sample.


; z; ?,_, -" ... . ,,", .... ~"~. ';~.~

t~- ,jr¥~" ~;""," ." ,," " .. " '·(r . " · ",'" -'~'<" • ',- .'- .•. :.' . . , - '\ if. "'>, • 1" ... .. ;. , ... '.! .• ; ;'. "if A " :; .... ft " .~-; ~ .'>. .1...": , ....... , .. , . "M" . ">" • . ,".,Ii'., ,

'" -" ... , . - ,.. ". " .. , '". . I 1);~ ~ ,. -,' "';''0, .• " '. .

/ 'lIt,'" "...,. "! ~H ',' '> •.. ~ "j • ". . .' . ' .. , I .• ,~ \ "'",.~. . '" ., I

;"t·«,..,"t •.. i "~i)'~",~~ '; '~'. ': {t'~~S~~of/" ~(r ,:\.;".~. ;'2B,:~1~0-~:.:" .~ ~ 1:' i ",~, ',e . 'f' )it,.- """'f;." . :'i}i'~'i;?':~:ii).~~, . '" ';,.~,: ,

f ,f·")t, "" f" ~ ~~If\oft.... i '".J}:".f '\'" . f \ .. ., ,i _ ·~L~.,·4' .• ';~~,)~ .. ~ " .' -: ." ". w ..

\.. F""", " '," '; _ '.~ ". ~., "'-c L ~1;.., ... "~",' "::.w. - '~.( ,",., 'r""'~":"" '~"..:....1~ __ " .... ___ , 't'l "1'''."..., ". _ ... ",. "!Ii~~if"'~".. I

,-,. ,(

... -~", "

40IJm Electron Image 1

Inca 64


Processing option: All elements analyzed (Normalised) Numher of iterations = 3

SlanJanJ : o Si02 I·Jul1·1999 12:00 AM Na AlhiIl' J-Jun-1999 12:00 AM AI A1203 I·Juo·1999 12:00 AM CI KCI I·Jul1·1999 12:00 AM Cr Cr I·Juo·1999 12:00 AM Mo Mo I·Jul1·1999 12:00 AM Fe Fe I·Juo·1999 12:00 AM Co Co I·Jul1·1999 12:00 AM Ma Ma I·Jul1·1999 12:1)1) AM

Element

OK Na K AIK CIK Cr K MoK Fe K Co K MoL

Totals

Weight%

24.83 0,67 0,38 1),29 2.03 1),53 68,39 0.46 2.42

100,00

Comment: 2H area.

Atomic7r

.13,34 1.00 0.49 0,2R U4 0,33 42,09 0,27 0,87

Fig. 4.27 EDS Analysis for 28.J Bottom Weld SAW· 2

60IJm - I Electron Image 1

Inca 65

Spectrum processing: Peak possibly omitted: 2320 keY

Processing option: All elements analyzed (Normalised) Number of iterations = 3

Standard : o Si02 I-Jun-1999 12:00 AM Cr Cr I·Jun·1999 12:00 AM Mn Mn I-Jun-1999 12:00 AM Fe Fe I·Jun·199912:00AM

Element Weight% AlOmic%

OK 8.33 24.05 Cr K 2.63 2.34 MnK 1.15 0.97 Fe K K7.89 72.65

Totals 100.00

COl11mcncEDS microanalysis of sample I 2R(SpccrumNo2)


• __ '''~'''''' .. y ~ !...... ~-ifJi h~:;_ , .... *- j4e.-___ ~_ - -"1f;;.<> ;':t~':: 1- • ~"__ \ ~1··'"' ".f;, , ... !.,"""'~::'.:!"!:::.<::;.~.,.~ ----.. -~ ..... ~ ~-':.""': '\""' "'(:: +" •

_ .l"~'" 7,.:: Yo' -i< t ~". . ... .. ,~r;~ .. ~"'C'... ~ ~ ~.,,,,,,.Y'" '" _~. .,'" .. -''''''''':!; ...• "iI.;;;_. , .. ~~.~-~ -~ ~~ _~-:.. ~..t~fi.J,q?, ~~ ~~.~;;,t :.:.- ~ ,t .. ~.~~... ~ ~ ~ • .:: p~. }!i!'!>i~_,,,,,-<~ij;;:..[, -'\ 'j_ r ... t _ ~''''''''''",,'' . ~. V:.', ·t ~'j ~ :l~t:. _~~.t-~(Ilo~·7"-:-'~~._ \.&~~'St;~ '1io<:._"::\.~'" :< ..... ~~'\~- 4, .•• J ..... ~-., ~ .... 119-~~ ... '"0$"" r,. ~. ~,,~T - ' .. ..,~\; •. ""..,..1'

:.._ J'~'. ,;,." . • "i :'~,: :,.."'!' ;':',";' ,;7::)>>,,?-t~ ,;" >' "'. '''''.:i.:. .~ ,'" .. .• t~. ''''-''::-~~.I'. "'" ,¥", __ ~.P ,.. .. I'J"':' ~~~;. .... , ..... ~ ... "'..; •• - .... ,~-~ ....... ,' l , • .,_ .... !'I..._ "':-~'''''''''''-·l'''''·.:1'0· 'J; ... ,...~ ",.'"-~ ... ~ "j " ~ ~'* J!-.... ~ ";-t."~' :-t>. , ..... : ... _l~:":':":-!O.V Ir. ~-"':'::""jltv,,,,,,,, \ ..... , *_L. _,-,-i',' " ....... ' ~<,. ,~!"'t ..... ~_ ,~ .. , '.,..

~4f.", ...... ;, ..... 'P "~V-' _,~··.';' .. <:Jt.i.JV--I":'f. .. '(4~: ~.If:IC.'" ...... ..-.Ji..t...'~ .. ,~ .. "~·r~

.. , .. >l .... ~ ........... ~ l!: .......... :.- .... :~~ ....... -.. ~ ...... -~ ~"':fi' >~ ~ , .... i.t ... ,::', , • ..;.:..r~'."'";;'" 9'!.~";:''f.,~' ~"". ~'-~do: ... ~~ .. :", ... <~.,. ?;,.:. -.~.~~, .... i

';1J.-,--" ..... t). .. ..L' ... ""'" '(.6 _.;-,~~.~~~l:'..\., .. ,~.I! 'J .. ,.~ ... ~"'-¥r:~,v .... ~ .. ~ ",,/r .f~~-:'~.· .t,'.:~.~ c.~'~\J" , ... ~i:" ';,,"".1;,>:,11 ;-1 . ~~. f¥{1. :J-"-II .. ~"'"f '. ,/!·"1~':' t !II' :t'i ..... :--....... -" '.f/I2:':;,,>)! ~ .. J ,\, • .t...J .' : 'I '".' '.:" . f.~, ".~;i.' ;,,' it y;.,}><~~ -~>~~:<: ..• ' ;A; .' "'';$~ "j' " •.• ~. -' .... '. ,,' " "(,.,, " 'f -;:; ... , .•. ... < .....

;. .... ' ~~ ... _"''-.. ~ ,-,II' "",," ,.~' f, ... " '"~~. r->" .... . ,_._ ... ~." ',.~;:!!l'''' ."'.' t /.,.". '-l; .. ".i! ' ',,..; f ",' " .. :~;'( .f '/I ~'/" ' 4> .. -'r'-" t(' r .. , • -·r,.:-:" ~, -;.,; ..... ': ••. :,w:-

, ~ j£;. ,... .." ""'::C~! ,:..lo',. ,~...'" ~~ ..... -. t:;o,~, ',~' J~, .. ' " ... ~ , ... ~ ~ .. , :.:-. ...... ;::..4.~~dll¥ .. ~.~ .",;"':" J1t~' - 1 .,- .. ~ - •

.. ,'." :: 'r·. ~ .. ' --'".~"'-·7'" ..;.. "-::"" :; . .f,'" .: ': -.. , ... 9/' ,'" .>~~~~ ,."-"~0j~:~fi .. i --;,; .~' ~~'II"'. ,:.~~~-'1'"'1r;"'-'''' '.

, '- ~ ~ •. ' ,. ~ ~., ,.,"" ~'. -' ' y' , ~ , . : >",.. ,;:.,:..., . ~ . . /1 -",1 I ~ '~~" 1!I.:'j.-t·,,· .' .I, • ",.,_ ;~. ~~, - i-'t.r ... t.' i't~ ' .. ~ "t .. ~, .;:, ''!f. ....,.~: \,. • ..' .• ~ ..... " r

' •. ;'i""h."i ..... ~, ... ,:'f:; i:)- .~:;~;...".::.;.J ~·,·"t .... , ·--",:4 ~~ ! ~ ~,,~,,9., j , ,~. '41:.," , ~ ~ ,:. •• r.;.:t.... ....'Iu. " r~ .""". :'ff:J. ~ ... '$"/.;' ~',.7~-;.& .... <,:"~. _~ :,~ .~~;.\. '~~.F" ,,~,.' ~ "'-' • .:r::. ~ .... ~ • ...t. ~ _ _ !p'r. ~~.!.~,;.' .~.It"·';"· ..... ~.~ """,«1',\'0 . ,'\ ~:"Y~~"""f' i.;/~:/"'';''''.~ ~~~~~.~_ ~?~..i€:*~:;~:,..~~:;..:.t'~· ....... ~~f· :*.r~,-· ';7::"> ~~'>"', J,-~

(

<"f" _.~ ._ .. "",,,,_,~?,,. -"~"""" ... 0 •• • .J't,. ~ .. ",,",",. _ ... :; "': ~/,,~ .. ~ .• _.'>"'!:..'~""'f>;.""r-.;;.;:.;;o;".~':;:..t."';.lA-""": . " ~'\.~ c,.~~

Ttl ,~ ..... ~r'-<', ",._... ;;'\"~ .... ~ " .... !"'..., ~ ·.'G·.!' ~"f\'.:.," .. . ;f~, ."~i:- -.+ .. ~: . ":'.~; _<::~:~:,;;""o .. ~~,,;:..:.:..""'.:;,\ ,<,: ~"I

.1; ~"I ~"-el.\' " "\to,' ~-~ ,:.., ~ .... -<"""; ...... - ...... -.... -: .... , ..... " + t!. v' J .~' -"'_j $rI) _.;" ~." ..... ..,..104~;~: ""K~""'·~'\(;.,::-· .;;;-,; .... ' .. rk;. •• "J

I e... t • .,~~'i Sf~~:;, .. ~ ~~~'8"k1,- ;~l.· . ~~~; '< ~~!:::1 ...... ul"un I Electron Image 1

Inca 66

Spectrum processing: No peaks omilled

Processing option: All cll'ments analyzed (NnrmaJiseu) Numhcr or ilerations = 3

Standard: o Si02 I-Juo-1999 12:00 AM No Albite I-Juo-1999 12:00 AM Mg MgO I-Juo-1999 12:00 AM AI A1203 I-Juo-1999 12:00 AM Si Si02 I-Juo-1999 12:00 AM S FeS2 I-Juo-1999 12:00 AM CI KCI I-Jul1-1999 12:00 AM K MAO-IO Feldspar I-Juo-1999 12:00 AM Co Wollaslooite I-Juo-1999 12:00 AM Fe Fe I-Juo-1999 12:00 AM

Elt":ment Wcight% Atomic%

OK 27.71 4S.49 Na K 9.24 11.2:\ MgK 2.55 2.94 AIK 1.51 1.56 Si K 5.40 5.39 SK 1.04 0.91 CIK 8.28 6.54 KK 1.55 1.11 Co K 2.05 1.43 Fe K 40.67 20.39

Totals 100.00

Comment 22 Inclusion in the sample.

Fig. 4.29 EDS Analysis for 22J Top Weld SAW· 2

{

,...---- _'F' _> 44 a; • "! ',~

') ,<~

? i>;~':"\ ' :... :"- \ '.;..' \"

, ""'- ,

'. •

- ,,,~

': .. ~

.. ,-,

(,,-'~

-;:'" '-") I'"

-'''(,-; , . .;,.~ l . -' ~ •

, ,~~_l'~'

.

....

I . 1 " I

501Jffi I Electron Image 1

."n[:'67


Processing option: All elements analyzed (Normalised) Nurnher of iterations = 3

Standard: o Si02 \-Jun-\999 \2:00 AM Cr Cr \-Jun-\999\2:00AM Fe Fe \-Jun-\999 12:00 AM

Element Wcight% Atomic%

OK 7.41 21.H2 Cr K 1.88 1.70 Fe K YO.71 76.48

Totals 100.00

Comment: 22 Iron Oxide in the Sample.


~- 40jJm Electron Image 1

• "1T1Iti~68

Spectrum processing: Peak possibly omitted: 1.048 keY

Processing option: All elements analyzed (Normalised) Number or iterations = 3

St<lndard: o Si02 I-Jun-1999 12:00 AM Si Si02 I-Jun-1999 12:00 AM Cr Cr I-Jun-1999 12:00 AM Mn Mn I-Jun-1999 12:00 AM Fe Fe I-Jun-1999 12:00 AM Mo Mo I-Jun-1999 12:00 AM

Element Weight% Atomic%

OK 7.07 21.00 Si K 0.25 0.42 CrK 2.29 2.09 MnK 1.17 1.01 Fe K 88.04 74.89 MoL 1.18 0.59

Totals 100.00

Commcnl:EDS microanalysis of sample 132 (Speclrum No2)


Electron Image 1

Inca 69

i G. D Acharya '·;"'i 'il"r;; ~~r1~".:~~;'~-:' ::~\')~tJ~~~~:··'·.r

Spectrum processing: Peaks possibly omined : 1.040.3.300 keV

Processing option: All elements analyzed (Normalised) Nurnhcr of iterations = 3

Stanuan.l : o Si02 1-Jun-1999 12:00 AM Si Si02 1-Jun-1999 12:00 AM Cr Cr 1-Jun- [999 [2:00 AM Mn Mn 1-Jun-[999 12:00 AM Fe Fe [-Jun- [999 [2:00 AM Mo Mo I -Jun-\999 12:00 AM

Element Wcight% Atomic?f'l

OK 6.59 19.74 Si K 0.48 0.81 CrK 2.27 2.09 MnK 1.39 1.21 Fe K 87.81 75.40 MoL 1.47 0.74

Totals 100.00

Comment:EDS microanalysis of sample 132 (Spectrum No I)

Fig. 4.32 EDS Analysis for 132.J Top Weld SA W - 2

Electron Image 1

'Inca 70

Spectrum processing: Peak possihly omitted: 5.425 keY

Processing oplion : All elements analyzl.!d (Normalised) Numhcr or iICrations = 4

Standard: o Si02 1-1un-1999 12:00 AM Na Albite 1-1un-1999 12:00 AM Mg MgO 1-1un-1999 12:[X) AM Si Si02 1-1un-1999 12:00 AM S Fe,,2 1-1ul1-1999 12:00 AM CI KCI 1-1ul1-1999 12:00 AM K MAD-IO Feldspar 1-1ul1-1999 12:00 AM Ca Wollastonite 1-1un-1999 12:00 AM Fe Fe 1-1un-1999 12:00 AM

Element Weight% Atomic9C

OK 37.23 58.68 Na K 8.74 9.58 MgK 3.66 3.80 Si K 3.47 3.11 SK 0.75 0.59 CIK 9.20 6.54 KK 2.60 1.68 Ca K 2.82 1.77 Fe K 31.54 14.24

T()t~lls I 00.00

Comment: 10 area.

Fig. 4.33 EDS Analysis for 10J As Weld SAW - 2/A

100l-lm Electron Image 1

.'1111[:'71

~~ .• ~" '., . '. . ,'}.' ' .. : ~


Processing option: All ckmcnts analyzed (Normalised) Number of iterations::;. 3

Standard: o Si02 I-Jul1-199912:00AM Na Albite I-Jun-199912:00AM Mg MgO I-Jul1-1999 12:00 AM Si Si02 I-Jul1-199912:00AM S FeS2 I-Jul1-1999 12:00 AM CI KCI [-Jun- [999 [2:00 AM K MAD-[O Fe[dspar I-Jul1-[999 12:00 AM en Wollastonite l-1un-1999 12:00 AM Cr Cr [-Jun-[999 [2:00 AM Fe Fe [-JUI1- [999 [2:00 AM

Element

OK Na K MgK SiK SK C[K KK Ca K CrK Fe K

Totals

Weight%

36.25 8.47 1.57 2.17 1.97 5.71 2.49 1.83 1.7 [ 37.83

[ IltJ.(X}

Atomic%

59.35 9.65 1.69 2.02 1.6[ 4.22 1.67 1.19 0.86 [7.74

Comment: 10 area_I

Fig. 4.34 EDS Analysis for IOJ As Weld SAW - 2/A

jil

1~ ;

",_!riZ;'"

40~m- -I Electron Image 1

Inca 72


Processing option: All elements nnalyzed (Normalised) Numhcr of iterations = 3

Stambn.l : o Si02 1·)un·1999 12:00 AM Mg MgO 1·)un·1999 12:00 AM Si Si02 1·)un·1999 12:00 AM Fe Fe 1·)un·1999 12:00 AM

Element Wcight% Atomicl}'(J

OK 31.95 48.20 MgK 16.67 16.55 Si K 30.53 26.23 Fe K 20.85 9.01

Totals 100.00

COlllment: lOA

Fig. 4.35 EDS Analysis for IOJ As Weld SAW - 2/A

~ ...... ~-. \* >', ~~"~~'~:~~' ;1: ~~;::._:v -:_,t_~-':-:~ "~ .. \ 4," 'U~""~.'!!~'l(~,_': "?-"'1'Y''''. ~,:,.r:..~;!H'i~.~~4>"~~:'~~~'~":_/:.~~_::':.~;" ...... '.~" ~;, i t J'/}.' .•.• "~'.: "~.' . . !c.~.\. ". ·'t'.1'\:.·· .' ;~, (~." '. '. _ I ' .. ",.~ . '...... " v

.. f·t .. .. '(.~ ':'.' ti'''.· . -..~t· ;". . "; .... .1 J '\ ',.. -.; .',,, "',"" '. '\.' ". ~; '.~, ' \!.1 ''i':o,. ,,'1 i " '>. -"l ~ . jol~. . "" '\ 'l." ;.,'. " ~~.; .,1...,. ". $;"" '4'. ',1' .:~." I

'c' •. ' •. ~. .".\ r ... ,... • H' . . , • ' -1-'" • , ,

, [{~r~:.,,, ,I:.(,'j :\ \".. r .. · "':x.. " " ". -" 1 ' .. ,\.",,,, '. .' . . ".r . ',~" .~ ~'1.." .• :~"(..""'" \ ..

):. .. ".;]i' . "". " 't' ; '" .' ''''.~ • "-f"'¥,,#,' ~ jh: "'-'.... .. .. , .,' ~"". , '~"\ 'f, .. " '.

*",1,,%),_ .~:."-"--""'-' -".:.....-., .. ;.,~ .... -.. ~-.. ""OOlJm I Electron Image 1

Inca 73

pectrum processing: No peaks omitted

Proce~sing tlption : All clements analyzed (Normalised) Numhcr of iterations == 3

Standard: o Si02 1-Jun-1999 12:00 AM Na Albite 1-Jul1-1999 12:00 AM Mg MgO 1-Jun-1999 12:00 AM Al A1203 I-Jun-199912:00AM Si Si02 I-Jul1-1999 12:00 AM S FeS2 1-Jun-1999 12:00 AM CI KCI I-Jun-1999 12:00 AM K MAD-IO Feldspar I-Jun-1999 12:00 AM Ca Wollastonite I-Jun-1999 12:00 AM Cr Cr 1-Jul1-1999 12:00 AM Fe Fe I-Jun-1999 12:00 AM

EIl!ll1cnt Weight% Atomic%

OK 19.2X 40.28 Nn K 5.92 8.61 MgK 1.17 1.61 AIK 1.09 1.35 Si K 3.64 4.33 SK 1.13 1.18 CIK 4.06 3.83 KK 1.40 1.19 Cn K 1.06 0.88 Cr K 1.38 0.89 Fe K 59.89 35.85

Totnls 100.00

Comment: lOB area.

Fig. 4.36 EDS Analysis for IOJ As Weld SA W - 2/A

6O.m Electron Image 1

Inca 74

4.6 Result or Micro Hardness.

This application note focuses on the use of a new micro-indentation instrument,

the Micro Hardness Tester (MHT), for determining the fracture toughness of

materials by directly measuring Vickers-produced radial cracks as a function of

indentation load[371.

Micro hardness was measured in 361 minimum PWHT. Top weld of trial No.

SA W-1 sample. on white patches of carbon-depleted area. The micro hardness

was in the range of216 to 222 VHN.

The micro hardness also carried out on 221 and 1321 of trial No. SAW-2, the

results clearly indicates higher value of micro hardness in lower joule value

sample and lower joule value of micro hardness in higher joule value sample. This

indicates coarse grain in lower joule value sample 221 and fine grain in higher

joule value sample 1321. (Ref. Table No. 4.12)

Table No. 4.12 Result or Micro Hardness

22J 132 J

Micro hardness-VIIN I\licro hardness-VHN

Coarse Grain Fine Grain

231 218

2J.t 219

235 214

4.7 Result or Hardness

The weld quality and its properties can be checked by different testing

method, the hardness measurement of weld metal zone indicates relation between

175

hardness and strength of the weld. Hardness tests are used to provide generic

information on the material properties (primarily toughness and strength).

Hardness measurements provide indications of metallurgical changes caused by

welding, metallurgical variations, and abrupt micro structural discontinuities in

weld joints, brittleness, and relative sensitivity to cracking under structural

loads[38).

The Vickers hardness survey made on welded specimen. The acceptable value of

hardness is ~ 235 VHN as per Clause No.7 .2.1.5 API 934. The average value of

hardness of bottom weld was 222.33 of trial No. SAW-I, 233.33 VHN of SA W-2,

219.67 VHN of SA W-3 and 213.33 VHN of SA W-4. The average value of

hardness of Top weld was 233.33 VHN of trial No. SAW-I, 235.33 VHN of

SA W-2, 218.67 VHN of SAW-3 and 214.33 VHN of SAW-4. This results clearly

indicate the better VHN value of Top and Bottom weld of approved consumable

i.e. SAW-4 compare to other three. Simultaneously the bottom average VHN

hardness is better compare to top weld VHN hardness in trial SAW-I, SA W-2,

and SA W-4 except the trial No. SAW-3. The Table No. 4.13 Show the top weld

and bottom weld hardness scattering. The bar chart Ref. Figure No. 4.38 also

represents i.e. trial No. SAW-4. All results can helpful to derive conclusion that

better compositions leads to consistent as well as with in the acceptable limit of

consumable hardness as required in code. The lower hardness value of bottom

weld is attributed to fine and uniform microstructure of weld metal. The grain

structure is fine indicating the better tempering effect due to subsequent layer of

weld. Difference in average hardness value in top and bottom weld of four trials,

the hardness is generally decreases of top and bottom weld from trial No. SAW-I

to trial No. SAW-4, except trial SAW No.2.

176

f'ig. No. 4.37 Location of hardness measurement on weld test coupon

Table No. 4.13 Result of Hardness

WELD METAL HARDNESS VALUES COMPERESSION OF FOUR TRIALS

USING DIFFERENT CONSUMABLES

SAW I (T/W) SAW 2 (T/W) SAW 3 (TAV) SAW 4 (TAV)

Hardness VHN Hardness VHN Hardness VHN Hardness VHN

227 235 218 212

218 238 219 215

222 233 219 216

A\e.222.33 Ave. 235.33 A \'C. 218.67 214.33

SA W I (BAV) SAW 2 (BAV) SAW 3 (BAV) SAW 4 (BAV)

Hardness VHN Hardness VHN Hardness VHN Hardness VHN

216 235 221 212

216 232 219 218

235 233 219 210

Ave. 222.33 Ave. 233.33 Ave. 219.67 A \'C. 213.33

177

240.-----------------------------------~

235.33 235 . -.------- r--- 233.33..... ____ ... _._ .... _

230

225 222.33222.33-r- r-

220

215

210 -

205 .

SAW 1

(TIW)

(81W) SAW 2

(TIW)

--------- - . __ ._--------

--.. _--_.--

218.67219.67 ---_ .. --- .~-------;

r-

I---

(81W) SAW 3

(TIW)

214.33 ___ .. _213.33 ,-- -

-

(81W) SAW 4

(TIW)

(81W)

IOSerieS1 I

Fig. No. 4.38 Average Hardness Comparison of Top weld (TIW) and Bottom

Weld (BIW) test coupon of four batch of consumable.

4.8 Effect of Manganese.

All of the high notch value samples contain higher wt percentage of Mn, while all

low notch value samples contains low or very lower wt percentage of Mn shown

in content analysis of fractured samples by EDX (Ref. Table No. 4.10). It

indicates that Mn has definite effect on notch toughness value of sample. All the

higher notch toughness value samples show the tiner grain size in microstructures

. This is due to Mn forming oxide and creating more number of nucleation sites

during solidification. They are producing fine grain microstructure. Trial No.

SA W - 4 samples have very consistent impact toughness result (Ref. Table No.

4.7). This is due to reduction in micro segregation, resulting from presence of

higher Mn. The following conclusion can be arrived from above result.

Microstructure analysis reveals that higher notch value samples show the

178

microstructure of fine tempered lower transformation products, which comprises

of martensite and bainite with carbide and ferrite. (Ref. Fig. No. 4.4A, 4.7 A, 4.SA

of plate I to 6). There fore it can be concluded that good notch properties are

attributed to the fine and uniform microstructure of weld metal. This is due to full

tempering of the weld resulting from thinner welds providing more number of

layers and heat input and raising the PWHT temperance more than 700°C.

In order to ensure safe service conditions of reactors made from 2 'A Cr I Mo 'AY,

material SAW AC weld metal has to meet requirements in terms of strength at

high temperatures as well as sufficient notch toughness at low temperatures. The

superior properties of this material compared to the conventional 2'ACr I Mo are

achieved by micro-alloying elements Cb and Y. Both carbide-forming elements

favour the strength at high temperatures but they are detrimental to the notch

toughness[ 15,16].

Manganese has been found to satisfy those requirements. Manganese increases

high temperature strength by solid solution hardening as well as toughness by

grain refinement due to favourable formation of suitable oxides and sulphides

during solidification. Furthermore the toughness level is characterized by

consistent values, without a significant scattering.

As the weld metal is solidifying within seconds, there is no risk at all for

segregations, as it is very slow solidifying base metal. Also the improvement in

properties is achieved by maintaining the Manganese content in the ranges as

imposed by ASME Code Case 2098-2. Consumables having higher percentage

of manganese give better notch toughness of weld (Ref. Table No. 4.2) .The

graph of temperatures vIs notch strength (CYN) shows the better result of notch

toughncss of specimen having PWHT 705°C, Shrs compare to 705°C 8hrs +

Step Cooling (SC)(Ref. Fig. No. 4.39). This indicates without step cooling,

highcr manganese in consumables improves the notch toughness of weld

179

specimen. The above discussion clearly indicates effect of manganese on notch

toughness of weld specimen. We derive conclusion that manganese, forms

manganese oxide and creates number of nucleation sites during solidification.

This helps in formation of finer grains and there by improves impact toughness.

This also reduces micro segregation of alloying elements, resulting in reduction

of scatter in impact properties. New consumable is having higher percentage of

manganese, which stabilize the CYN welds.

;::!.

J31,-------------~~--------------------r_------------_.

1=3:::'" . • ~ I - ----- ----- --~----

• I •

- -- -- -~- -------- ----I

.- . J) :.,. 1.,1

FIG 4.39 The graph of temperature Vs Notch Strength

(Featuring weld metal with increased Mn·content summary of tests obtained

from AC single wire welds)

180

chemistry strength properties

[wt-%) PWHT test temp, Rp,,2 Rm A [,C'hrs) -+ ['C) [MP~1 [MPa) [%)

C G.C75 705'10 5'39 6U 23

Si 0.G9 705/40 491 61'32 23 2C

Mil 1.24 710/8 571 674 24 :> oJ.CG5 710.:30 547 6--::-'::' 2E,

S 'J.CG5 70" .... 18 L74 52~ 2D

Cr 2.31 45':'

70 ",'L 8 ,~~ 5C7 1:· -L,'

MJ 0.94 710.·'2 c,:.g 5C·~· 13

Ni 0.G3 70" .... 18 432 t~·O 51", 17

V 0.28 70 " .... L 8 390 4~" 2e,

AI oJ. COg

Cu 0.%

N 'JC11 welding data

Nt- oJ.CH wire cI ia 4mm

As oJ.CG5 allllJera(le AC 550 A

Sn oJ.CG4 voltage 29\/

Sb <.DC1 travel speed 55 em/mill

,preheatin(1 temp. 180~G

interpass temp, nJ'.25'YC

Fig. No, 4.40 SA welding or 2 IA Crl Mo V by union sl Cr Mo 2V!

UV430TTR W

181

4.9 Effect of MnlSi And MnlS Ratio

Thyssen has carried out laboratory tests for the same consumables used In our

study project and our results also matched with the same.

The restriction of 0.8S% manganese content In weld metal was originally

developed due to a number of reasons for 2.2SCr-1 Mo and then transferred to

2.2SCr-1 Mo-V material as it became available. The main reason is that instead of

forming carbide manganese forms an isotropic MnS particles together with

sulphur. Many researches reports that such particles could increase strength of the

weld metal when they are present in limited quantities only. By the significant

increase of amount of such inclusions in weld metal, they drastically decrease

material strength and other mechanical properties[ I S]. But the formation of such

particles can only processed when required amount of sulphur is supplied. At the

same time sulphur in weld metal is segregating on the grain boundaries degrading

the mechanical properties and can form a number of other precipitations in

addition to MnS. Basing of these facts, last year the amount of sulphur in weld

metal was significantly decreased by use of clean wire and reduced sulphur

containing fluxes. Thus the role of manganese in degradation of mechanical

properties of material has become not important in a higher extent[ I S]. At the

same time it is well known that manganese can improve strength propel1ies of

material through its carbides and austenite grain size reduction. It is also reported

that manganese has a good influence on crack resistance.

Our previous flux of trial No. SAW-I, SA W-2 and SA W-3 had neutral carbon

and manganese burn-in or burnout behavior therefor ensuring carbon and

manganese contents in weld metal in the same range as in welding wire. But as

report of testing weld mctal produced with such flux did not posses required

toughness (Ref. Table No. 4.2). Our optimized flux of SA W-4 on the one hand

182

has improved low temperature toughness. (Ref. Table No. 4.2), Increased

cracking susceptibility wire on the other hand it posses a complete strength. Such

properties were achieved by flux modification, which provides a lower carbon

(reduced from O. I I % to 0.08%) and higher manganese (increased from 0.58% to

1.2%) concentration in the weld metal. The use of raw components with low

sulphur content result in the fact that optimized flux had no influence on the

sulphur content in the weld metal and the use of sulphur clean wire limit sulphur

concentration to a very low level (lower to equal to 0.005%). Together this

manganese provides excellent mechanical properties of a new wire flux

combination while being in accordance to international standards (maximum

manganese content is restricted to 1.3%)[15]. Fig. No.4.41 shows the Optimized

flux comparison.

Sn,gIeWife 4fntn. ~ .. I4Nn .... PWHT: 7051'1(11

1"'-1;> ... 1 [j£'i1lij] ..,1ICf ......... " ... PMtr.706m.

Singl ........ _ 1~-'-t2-1.11lK1 T_6em,4".

Figure 1

Fig. No. 4.41 Optimized nux (comparison) Thyssen Germany[IS]

Samples of weld metal with four consumable trials No. SAW - I, SAW - 2,

SAW-3, and SAW-4) of different manganese and silicon content were examined.

It would be seen that the number of non - metallic inclusions trapped in the weld

during solidifications are increased as the Mn/Si ratio of the weld is decreased

(Ref: 1.29> 1.04).

183

I. The notch toughness of 2.25'frCr - I %Mo - 0.25V welds is consistent as

Mn/Si ratio increased and Mn/s ratio decreased.(Ref. Table No. 4.14)

2. Metallographic examination indicates that an increase in the Mn/Si ratio of

the weld has decreased in inclusion content of 2.25% Cr, 1% Mo, and

0.25V welds.

Table no. 4.14 MnlSi and MnlS Ratio of consumables

Consu.

Ratio

Mn/Si

Mn/S

SAW-l

9.66

580

SAW-2

7.66

306.66

4.10 Effect of Tempering Temperature

SAW-3

13.87

222

SAW-4

17.42

174.2

Development of various types of carbides depends upon tempering temperature

and time. The test result of sample 22 J and 132 J of two samples of lower and

higher notch toughness value, the microstructure shows the mixture of martensite,

bainite and various types of carbides. The lower notch toughness value samples

reveal the microstructure of a mixture of coarse under tempered lower

transformation product which comprise of martensite and bainite with c,u'bide and

ferrites. The grain structure is coarse indicating excessive weld metal temperature

and possibility of segregation of prior grain boundaries. While in case of higher

joule value samples reveal the microstructure of fi ne tempered lower

transformdtlon products, whIch compnses of martensIte and bainite with carbide

and ferrite. The grain structure is fine indicating proper control of welding

parameters including weld metal temperature.

The color approach indicated no segregation at the pnor austenite grain

boundaries from where the transformations have occurred. It helped in confIrming

184

the presence of coarse mixture of under tempered lower transformation products

comprises of bainite and martensite. (Ref. Fig. No. 4.38 Plate 7 to 12 of 22J)

The color Metallography of lower notch value sample microstructure indicates

segregation of the prior austenite grain boundary of weld where the

transformations have occurred. (Ref. Fig. No.4.3B Plate No.7 to 12 of 22J).

The similar color Metallography of higher joule sample indicates no segregation

at the prior austenite grain boundaries from where the transformation has

occurred. This helps in confinning the presence of coarse mixture of under

tempered lower transformation product comprises of bainite and martensite. (See

Fig. No. 4.4B Plate No.7 to 12 of \32 J).

Similar conformations have been also observed in number of microstructure

compared for lower joule value samples and higher joule value samples. SEM

image without PWHT of fracture sample of lower notch toughness (Ref. Fig. No.

4.14) 10J at RT temp reveals irregular transformation; it gives lower joule value at

room temperature. Therefore it may be concluded that full tempering of weld

provides finer microstructure and without PWHT result in weaker weld. Full

tempering effect is achieved by proper weld bead geometry. The deposition of

thinner weld layer provides more number of beads resulting in better tempering

effect to subsequent layers.

Bead tempering alone is not sufficient for refinement of grains, PWHT is one of

the most important process for acquiring necessary toughness property of weld.

Experiments conducted by number of research organization as well as

consumable manufacturers suggest that temperature. Above 700°C PWHT is

necessary to adequately temper all forms of complex carbides. From above

discussion we can arrive the conclusion that the wcldi ng of 2 I;'> Cr- I Mo- I;'> V

forms various types of carbidcs. It is very important to temper that carbide to

185

achieve consistently high impact toughness. It has been found that this can be

achieved by, the thinner weld deposit layer which gives full tempering of

subsequent weld layers. PWHT must be carried out at a temperature of not less

than 700° C. This temperature range of PWHT is enough to temper all forms of

complex carbides in 2 ';.1 Cr -I Mo - ';.1 V steel weld.

4.11 ElTect of Position of Notch

The variability of results may be attributed to the bead geometry as well as notch

position, since welding process for thick metal section consists of number of weld

passes, each forming biddle (convex) shape, naturally the middle portion having

more metal, provides better tempering effects. This necessiate appropriate notch

location. The notch forms at mid bead give scattering effect. However specimen

from bead overlap area gives better results, in practice while preparing test sample

for CVN test, positioning the notch at temper bead thickness, is a chance factor,

therefore inconsistent result can also be attributed to this factor[ 1,16]. The thyssen

Germany has carried out laboratory test to correlate notch toughness and location

of notch on overlap bead or mead bead. The notch toughness and location of

notch on overlap bead or mead bead give wide variation in the results. (Ref. Table

No. 4.15 and Fig. No. 4.42) The results are matched with experimental data. We

reach to the decision that impact toughness at the mid bead thickness shows

scattering however specimens from bead overlap area gives better results. This is

due to tempering of overlap region.

186

PWHT

C/hrs

705/10

705/8

705/40

T Rpo.

Rm AS Loc _20°C _30°C -40°C 2

C MPa % CVN J J ./ MPa

rt 569 667 22.7 Overl 2-10 248 259 220 231 192 208 208

rl 563 662 23.4 Mid. 192 192 176 180 141 178 172 147

rt 491 608 25.5 Overl 193 178 208 44 176 204 176 102

482 390 459 17.0

Table 4.15 Mechanical Properties of Thyssen Germany Results

Temper embrittlement; Process SAW (single wire I tandem

welding)

Union S 1 CrMo 2 V I UV 430 TTR-W wire, heat-no. 642230 I nux

3830

187

226

170

192

200

,

150 ________ 1 __ _______ 1 _______ , __

:2: z 100 > <>

50 ----'------~~~o_c~~~_cC~~~~-1 --------,-- ---,- ---,-------

0 -70 -60 -50 -40 -30 -20 -10 o

Temperature rC]

200

, 150 _ _ -l- __ - -1- ______ .j. _______ I- ____ _

:2: z 100 > <>

50 __ =-~_-_-_-_ -.::-::~_---::--c_c_~_c_~_c,cc_c_c_~_c_~_c_c,"_c_~_c_~_c_cc

0 -70 -60 -50 -40 -30 -20 -10 o

Temperature 1"C]

200

, , 150 -,-----

, L _ _______ J _ ______ L _____ _

100 ------j------

50

o -70 -60 -50 -40 -30 -20 -10 o

Teroperature eC1

Single Mid Bead and Overlap zone

188

z > o

2: z > "

2: z >

"

200 -~;;~==~-:----:-----:-----:----:----I

, , 150 -

_________ -1 _______ L ______ ~I~ ______ J ____ _

,

100 - - - - - - -1- - - - - - - -r - - - - - -

50 - - - - - - -,- - - - - - - - - - - -,- - - - - - - -; - - - - - - -;- - - - - - --

o -70 -60 -50 -40 -30 -20 -10 o

Temperature rC]

, , , ___ ~ _____ ~_i _______ L ____ _ ,

100 - "!-------

50 - - - - - - -,- - - - - - - -, - - - - - - - -,- - - - - - - - ,- - - - - - - -,- - - - - - - -; -

o -70 -60 -50 -40 -30 -20 -10 o

Temperature [0C]

200

E~~'

~=.+.o

150 - - - - - - _1- ______ j _ - - - - - - L - - - - - - _1- - - - - - - jL-_-... -~::::::~?1

100 - - - - - - -1- - - - - - - l' - - - - - - -t-- - - --, ,

o -~, --~_T~~--~----~~~~----_r----~----~ -70 -60 -50 -40 -30 -20 -10 o

Temperature ["e]

Fig. No. 4.42 Graph of single and Tandem mid bead and overlap zone.

189

4.12 Elfect of Inclusion and Impurities

The base metal and consumable contains vanous types of impurities namely

sulphur and oxygen as welding process consist of following four stages.

Preheating, Welding, Solidification, PWHT and during all four stages complex

metallurgical phase changes occur which affect ultimate microstructure. All the

above-mentioned impurities affects singly or multi casual. The result of EOX can

be summarized as follows. (Ref. Table No. 4.10)

Table No. 4.16 Proportion of Impurities in Fractured Samples

LOWER JOULE VALUE SAMPLE HIGHER .JOULE VALUE SAMPLE

S found Not found

Oxygen 10.7 to 59.5 wt% Oxygen 7.07 to 8.33 wt%

The presence of sulphur in the weld metal forms the free sulphur, and also the

sulphur in the form grain boundary sulphides, which can be linked with initiation

of cavitations on the grain boundaries resulting in early failure. All of our lower

joule value samples exhibited this phenomenon. The absence of sulphur in higher

joule value sample avoids free sulphur and grain boundary sulphides providing

high interfacial strength with the matrix[7,22,16]. FUl1her it can be stated that the

presence of sulphide may be the result of solution of manganese sulphide during

the cooling cycle and subsequent preferential reprecipitation at grain boundary

site during the cooling. As discussed previously the effect of Mn content is most

critical in deciding the notch strength of weld[22].

In the end, the lower notch toughness values are interpreted due to coarse under

tempered lower transformation product with segregation at the grain houndary.

The Bainite fine packet size is associated with welds with low inclusion content

and a coarse packet size with high inclusion content, therefore an argument is that

oxygen content in the form of oxysulphide inclusions played role in controlling

190

bainite packet size. From the above result EDX. Clearly shows that the lower

notch toughness value samples contain more weight percent oxygen and sulphur,

forming oxysulphide inclusion while in case of higher joule value samples

sulphur is absent, hence it can be argued that oxy sulphide inclusion decrease

notch toughness. It has been noticed that lesser impurities in steel gives better

result of impact toughness. Present consumable SA W-4 has lower impurities

compare to consumable SAW-I, SA W-2 and SA W-3, so it gives more cleaner

weld and better and consistent impact toughness properties.

191

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Documents

CHAPTER-IV RESULT AND DISCUSSION - Shodhgangashodhganga.inflibnet.ac.in/bitstream/10603/93300/14/14chapter 4.pdf · were selected from the weld coupon as per ASME Section VIII, Diy