THE EFFECT OF WELDING ON MECHANICAL AND …...The difference between Vickers and Knoop is that the...

ELK ASIA PACIFIC JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING

ISSN Online: 2394-0425; Volume 1 Issue 2 (2016)

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……………………………………………………………………………………………………………………

THE EFFECT OF WELDING ON MECHANICAL AND MICROSTRUCTURAL

PROPERTIES OF MATERIALS- A CRITICAL REVIEW

Md. Anis Raza

Post Graduate Scholar, Production

Technology and Management,

Birsa Institute of Technology, Sindri,

Dhanbad, Jharkhand

[email protected]

Sudhir Kumar Kashyap

Sr. Principal Scientist, CSIR- Central

Institute of Mining & Fuel Research,

Dhanbad, Jharkhand,

& Professor, Academy of Scientific &

Innovative Research

(AcSIR – CIMFR)

[email protected]

Rakesh

Assistant Professor,

Deptt. Of Production Engg, Birsa

Institute of Technology, Sindri,

Dhanbad, Jharkhand,

[email protected]

ABSTRACT

Keywords: steel casting production, tensile strength, HAZ, plasma weldin

Welding is extensively used in the finishing stage of steel casting production and in fabricating components for

joining. The ease of welding as well as the effects of welding on mechanical properties is thus very pertinent

considerations in the production of engineering components. The purpose of this review is therefore to summarize

and evaluate the published literature with respect to weld ability and the effects of welding processes on mechanical

properties. In this paper a critical review has been presented on the effect of different welding processes like friction

stir welding, arc welding, laser welding, plasma welding on mechanical properties such as tensile strength,

toughness, hardness and microstructural properties of different grade of steels. The different steels which were taken

for studies are stainless steel, low carbon steel, high strength low alloy steel, aluminum alloy etc. After critical

review of related papers it was concluded that there were microstructural change as more pearlite and ferrite were

present in weld zone and HAZ compared to base metal that resulted in increased hardness and loss of tensile

strength. The welding parameters like welding speed, heat input and welding conditions have also resulted on the

affect the weld joint properties and weld joint strength. The mechanical properties of weld joints have also been

affected by filler material composition and type of welding used. Finally, out of all the welding processes friction

welding and laser welding led to superior quality compared to other fusion welding.

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INTRODUCTION

Welding is a permanent joining process in

which two or more parts are coalesced at their

contacting surface by suitable application of

heat and/or pressure [1]. In modern time

welding is widely used in various industries

like power generation, oil and gas, marine

transportation, petrochemical industry etc. It

has advantages over other joining process due

to design flexibility, cost saving, overall

weight reduction and structural performance.

Welded joints have high corrosion resistance

compared to bolted and riveted joints and thus

different variety of joints can be made by

welding. Due to such advantage it is widely

used in boiler, pressure vessels, off structure,

naval vessel and mining machinery of

underground and open cast mines [2].

Welding is considered as an extension of hot

forging which Egyptian and other eastern

Mediterranean used for making weapon and

tools. Modern welding technology was

established in 1800s by an English scientist

Sir Humhrey Davy. In 1801 Sir Davy

observed that electric arc could be struck

between two carbon electrodes. In mid 1800s

Nikolai Benardos, a Russian working on a

laboratory in France was granted a series of

patent for carbon arc- welding process. In

1892 an American, Charles Coffin developed

arc welding using filler and electrode. The

resistance welding such as spot welding and

seam welding were developed by E.

Thompson in between 1885 and 1900 [1].

LITERATURE REVIEW

Welding has eminent effect on mechanical

property of materials due to heat produced

during welding. Some of the properties which

affect the material due to welding are:

1. Tensile property :

Tensile strength is the maximum stress that a

material can sustain in tension. In other words

we can say the amount of applied load per

cross sectional area that a material can

withstand before failure. Mathematically it is

calculated as the ratio of maximum tensile

load to the original cross section area.

As per a research done on AA6061 aluminum

alloy using GMAW (Gas Metal Arc

Welding) it was observed that in GMAW

joints elongation (in length) and reduction in

cross section area were 8.4 % and 5.8 % while

of parent material were 18% and 12.24%. It

suggests that there is reduction of around 53%

in ductility due to GMA welding. The same

material when welded using FSW the

reduction were 14.2 % and 9.56 % [3].

Another test was carried to study effect of Gas

Tungsten Arch Welding (GTAW) on AA6061

T6 alloy by machining the alloy to ASTM E8-



04 standards and welding was done using

AlMg5 as filler alloy wire for welding and

following result was obtained [4].

(Refer table 1)

(Refer figure 1)

From Table 1 and figure 1 we can conclude

that toughness has decreased due to welding

and the tensile strength of the specimen has

reduced about 54% [4].

Tensile test was carried on torr (torsteg) steel

joined by Shielded Metal Arc Welding

(SMAW) and the transverse tensile strength

observed was 524 MPa while that of parent

material was 523 MPa. It is higher than the

minimum specified tensile strength. Similarly

transverse strength for Cu-TMT bar was found

to be 600 MPa which was above the MSTS

(minimum specified tensile strength) [5].

A study was done on rolled plate of ferric

stainless to see the effect of CCGTAW

(continuous current gas tungsten arc welding),

PCGTAW (pulsed current gas tungsten arc

welding) plasma arc welding (PAW), GTAW,

SMAW, GMAW and concluded that the joints

made by the PAW (tensile strength 990 MPa)

were higher by 40 % compared to CCGTAW

(600MPa) and by 35 % to PCGTAW (650).

But there is reduction in strength by 41 % in

case of SMAW and 44 % in GTAW. The

tensile strength of base metal was 524 MPa.

The elongation study of each specimen

showed that PAM joints exhibit higher

ductility than other two types, but less than the

parent material. The elongation in base metal,

PAW joints, CCGTAW joint and PCGTAW

joint was 12 %, 7.5 %, 4.5 % and 6.2 %

respectively, which means there is reduction in

ductility by 62 % and 48 % in CCGTA and

PCGTAW respectively. In SMAW and

GMAW the reduction in ductility were 30 %

and 39 % respectively [6] [7].

The weld joint tensile test was carried on

stainless steel to see the effect of GTAW and

SMAW and found that GTA welds exhibits

greater strength and ductility due to equi-axed

fusion zone grain morphology and protective

nature of the shielding gas. By the addition of

oxygen in the shielding gas in GTAW and

addition of Ar+O2 backing in SMAW reduced

the ductility and strength. The addition of

copper resulted in increase of strength but

reduction in ductility. It has also been

observed that initially with increase in

austenite, strength decreases and with further

increase in austenite content results as increase

in strength [8].

The effect of different welding process on

naval grade High Strength Low Alloy steel

(HSLA) was studied and found that weld

metal was comparatively stronger than the

base metal. The yield strength of all type of

welding joints on HSLA steel was higher than

the base metal and this was associated with

precipitate hardening. The increase in strength

in case of FSW (Friction Stir Welding) was

8% more than the base metal due to fine grains



of acicular, upper banite and small martensite

region. The comparison between various weld

joints tensile strength can be done from figure

2 [9]. The effect of filler material was

observed using E309L and 18Cr-8Ni-6Mn

(18-8-6) as filler and found that tensile

strength of both weld joints were 1230 MPa

and 1260 MPa respectively which are quite

low compared to base metal (1720 MPa). The

failure has ductile mode. The joint efficiency

was around 72% compared to base metal when

calculated on UTS (Ultimate Tensile Strength)

basis [10].

(Refer figure 2)

Another study made on HSLA HY-80 steel

showed that during tensile test all the

specimens failed at the base metal which

means HAZ (Heat Affected Zone) and weld

metal has higher strength than the base metal.

The yield stress and strain of welded specimen

were 639 MPa and 6.8% respectively and of

the base metal was 577 MPa and 20.7 % [11].

From the study of FSW (friction stir welding)

on ferric stainless steel we can conclude that

ultimate tensile strength of base metal and

welded joint was almost comparable (536MPa

and 574 MPa respectively) when failure occur

in base metal. A notched tensile strength test

was done to know the tensile strength of

friction stir welded joint and was found to be

1030 MPa which is 57% higher than the base

metal [12]. The Friction welded joints showed

ductile mode of fracture and shear failure of

material occurred at the fractured surface [13].

In study of GTA and Laser beam welding on

duplex stainless steel showed that the failure

occurred in the HAZ and they showed ductile

mode of fracture. The UTS of both joints were

less than the base metal by 1 % and was

associated with ferrite – austenite ratio that

resulted due to high cooling rate. The laser

beam welding produces better mechanical

property due to finer grain size [14]. The weld

joint made using low hydrogen ferritic steel

consumables have high tensile strength due to

ferrite presence in the weld metal [15]. A

comparative study was made on stainless steel

joints made by TIG, Laser and Laser –Tig

hybrid welding and it was observed that TIG

welded joint showed a cup-cone shaped

fracture while Laser and Laser-TIG hybrid

showed shear fracture. The tensile strength for

TIG Laser and Laser-TIG hybrid were 560,

733 and 683 MPa respectively [16].

2. Hardness

The ability of materials to resists penetration,

abrasion, scratching or cutting is known as

hardness. It is the property by which material

resists permanent deformation. Various

hardness tests are available such as Rockwell

Hardness Test, Vickers Hardness Test, Brinell

Hardness Test, Knoop Hardness Test,

Scleroscope Test and Durometer Test. In

Rockwell Hardness test a cone shape indenter



or a small ball is pressed into the specimen.

Similarly Vickers Hardness test and Knoop

Hardness test use Pyramid shaped indenter.

The difference between Vickers and Knoop is

that the later use indenter having length to

width ratio about 7:1. Knoop Hardness Test is

generally done to measure micro hardness

which means measuring small thin specimens

or hard material which might fracture when

heavy load is applied.

Using Vickers Micro hardness testing machine

the hardness value of parent material (AA6061

aluminum alloy) was 105 VHN while of

GMAW and FSW (Friction Stir Welding)

joints was found to be 58 VHN and 85 VHN.

This suggests that the hardness across the

welded section has decreased in the GMAW

specimen and increased in FSW [3].

The effect of hardness with distance has been

checked using Rockwell hardness as per

ASTM E18-05 standards on AA6061 T6 alloy

and the result obtained can be seen in table 2

and figure 3. Hardness is expressed as HRF

which means Rockwell test is carried out at

load of 60 Kgf [4].

(Refer table 2)

(Refer figure 3)

A hardness examination was carried on torr

steel using 10 kg load and found that hardness

vary along the different zones of the specimen

from 146 HV to 236 HV (figure 4). Similarly

for Cu-TMT bar it varied from 256 VHN to

422 VHN (figure 5). The hardness values at

some location in HAZ were found to be

significantly higher in one or two locations.

This shows that weld joints in both of these

show sufficient internal soundness [5].

(Refer figure 4)

(Refer figure 5)

From the hardness examination by Zakaria on

industrial low carbon steel (0.19 wt. % C) it

can be said that maximum hardness was in the

weld metal as well as in the heat affected

zone, which was result of residual stresses just

after welding and grain size etc [17]. The

micro-hardness of different zone can be easily

seen in figure 6.

(Refer figure 6)

Another microscopic observation was done on

HAZ of a weld joint made of 30CrMo5-2 plate

(base metal) using austentic stainless steel

EN160018 8 Mn B22 as filler material and the

result obtained showed that, although filler

material has very low hardness yet when we

move away from the fusion boundary the

hardness value of HAZ increases slightly [18].

The study of friction stir weldment of X80

(0.13 C, 1.52 Mn, 0.26 Si, 0.17 Mo, 0.034 Cr,

0.026 Ni, 0.0002Nb, 0.003 Ti, 0.062 V, 0.041

Al, 0.032 Cu, 0.0003 B) concluded that there

was little softening of HAZ and the overall

hardness of weld area was more compared to

base metal and the hardest zone was TMAZ



(Thermo Mechanical Affected Zone) at the

advancing side. The softening of HAZ was

due to lower peak temperature attained in the

FSW HAZ and the hardness in TMAZ is due

to formation of acicular phases such as LM

and LB. In L80 (steel (0.32 C, 1.20 Mn, 0.35

Si, 0.65 Mo, 1.30 Cr, 0.20 Ni, 0.04 Nb, 0.04

Ti, 0.05 V, 0.04 Al, 0.20 Cu, and 0.0025 B)

hardness of TMAZ was higher compared to

HAZ (figure 7). A comparison was made

between hardness of fusion welding and FSW

on X 80 steel as shown in figure 8 and

concluded that in fusion welding hardest zone

was HAZ while in FSW it was TMAZ [19].

On ferric stainless steel the hardness varied

from 320 HV to 382 HV which is higher

compared to base metal (170 HV) as shown in

figure 9 [12]. The relation of hardness and

post welded banitic structure was studied for

FSW and concluded that hardness increases

almost linearly with decreasing banite-lath and

packet sizes. The maximum hardness was

found in the region of upper banitic structure

and the lowest hardness was in the HAZ. In

the stir zone due to frictional heat and plastic

flow; granular banite and recrystallized eqi-

axed polygonal ferritic structure were formed

in HAZ. In the hard zone classical lath- like

upper banitic structure was formed [20].

In ferric stainless steel the hardness value of

plastic zone (PZ) is higher than partially

deformed zone (PDZ) due to formation of

finer grain size in PZ [13].

(Refer figure 7)

(Refer figure 8)

(Refer figure 9)

A research was done on low carbon steel plate

(SAE 1020 steel) to see the effect of coarse

initial grain size and heat input on

microstructure using heat input for welding as

0.5, 1 and 2 kJ/mm and concluded that lower

heat input (0.5 KJ/mm) resulted in maximum

hardness due to formation of martensite.

While observing effect on Initial Coarse Grain

(ICG) size it was seen that the maximum

hardness was obtained for ICG specimen with

heat inputs of 0.5 and 1 kJ/mm and this was

associated with high carbon, martensite and

banite. As the heat input increased to 2 kJ/mm

there was decrease in the hardness of weld

metal and HAZ due to ductile phases, pearlite

and ferrite formation. For the same heat input

the coarse grain has very little effect in

hardness of weld metal (figure10). The

hardness value from the fusion line of base

metal was decreasing almost linearly, while of

coarse grained one was fluctuating due to

existence of martensite and polygonal ferrite

[21]. The effect of ICG on hardness of inter-

critical HAZ can be observed by figure 11.

The maximum hardness value was associated

with heat input of 0.5 kJ /mm due to the

formation of coarse grain; similarly the

maximum hardness loss was seen with heat

input of 2 kJ/mm due to formation of

polygonal ferrite and fine grain pearlite in



specimen 1 &2, and fine grain pearlite in

specimen 3. While the hardness of specimens

with heat input 1 kJ/mm was between the

above results [22]. The increase in heat input

is inversely proportional to hardness as

experiment showed when heat input increased

from 5 to 8 kJ/cm and hardness decreased to

148 BHN from 160 BHN [23].

(Refer figure 10)

(Refer figure 11)

In the study of hardness of CCGTAW,

PCGTAW, SMAW, GMAW and PAW

welded ferric stainless steel specimen it was

observed that regardless of the welding

process hardness value of weld region is

greater than HAZ as shown in figure 12 [6]

[7].

(Refer figure 12)

The hardness study of different weld joints of

HSLA steel showed that there was

transformation of banite ferrite with carbide

and acicular ferrite at the weld joint that

resulted into high hardness. The hardness in

case of FSW is higher compared with HAZ

and base metal of parent material due to

plastic deformation, continuous dynamic

recrystallization and fast cooling rate. Due to

micro-segregation of alloying agent the

hardness increased where prior-austenite grain

size was smaller compared to fusion line. [9]

The effect of filler materials E309L and 18-8-

6 showed that the maximum hardness was in

the HAZ and the hardness decreased in from

HAZ to base metal (as shown in figure no13)

and the increased hardness of weld zone may

be associated with the martensite formation

[10]. In HSLA HY-80 steel the weld zone has

higher hardness value (275 HV) than the

parent metal (235 HV), and the maximum

hardness was achieved by SMAW and lowest

by GMAW when comparison was made

between SMAW, GMAW, and Shielded Arc

welding [11]. Another study was done to see

the effect of Nb (Niobium) microalloyed

HSLA steel and found that the parent steel

was harder than the Nb alloyed steel [24].

(Refer figure 13)

The study of hardness on laser beam and GTA

welded joints on Duplex stainless steel

revealed that there is no significance

difference in hardness of WM, HAZ and base

metal in-spite of variation of ferrite and

austenite ratio [14].The welds having acicular

ferrite structure have higher hardness [15].

The examination of microhardenss in

Titanium Aluminide varied with change in

welding speed and heat input. The fusion zone

was wider at low speed and high heat input

(analyzed from figure 14) [25].

(Refer figure 14)

In the study of ferrite morphology of stainless

steel weldment it was concluded that ferrite

distribution in the austentic matrix affects the

stress rupture behavior particularly at elevated

temperature. And the ferritic distribution

mainly depends upon heat input [26].



3. Microstructure

The structural features such as grain and

phase structure which are subjected to

microscopic observation are called

microstructure. Microstructure is very

useful in study and characterization of

materials. Various microscopic techniques

are Optical microscopy, Electron

Microscopy, Scanning Electron

Microscopy etc.

In AA6061 aluminum alloy the base metal

contains coarse and elongated grain with

uniformly distributed very fine

precipitates, on the other hand in GMAW

the fusion zone have dendritic structure. In

FSW the weld region of FSW contains

very fine equiaxed grains. The dendritic

structure was due to fast heating of base

metal and fast cooling of molten metal

(molten by welding heat) and the fine

equiaxed grain formed in FSW may be due

to dynamic recrystallisation occurred

during welding [3].The microstructure of

AA 6061 T6 alloy was studied using

scanning electron microscopy (SEM) and

found that grain growth took place at HAZ

[4].

In Low alloy steel 16Mo3 the

metallographic observation was made by

an optical microscope Olympus PMG3 for

MMA and MAG joints and following

structure were obtained for different region

as shown in figure15 [27].

(Refer figure 15)

The optical microstructure examination of torr

steel show that the weld metal has refined

polygonal pearlite structure and the HAZ has a

transition to coarse ferrite structure with large

volume of pearlite. Similarly in case of Cu-

TMT bar the weld metal has ferrite –pearlite

structure and the HAZ has Widmanstatten

ferrite structure with some percentage of

banite [5].

From the microscopic examination (figure 16

and 17) of industrial low carbon steel (0.19 wt.

% C) shows that the microstructure of weld

zone and HAZ are different. HAZ contains

widmanstatten ferrite and some colonies of

pearlite, while that of base metal has eqiaxed

ferrite grains [17]. During cooling of the HAZ

first transformation occur as δ-Fe to γ-Fe and

second transformation occur as γ-Fe to α-Fe

transformation [28].

(Refer figure 16)

(Refer figure 17)

Another microscopic observation was done on

HAZ of a weld joint made of 30CrMo5-2 plate

(base metal) using austentic stainless steel

EN160018 8Mn B22 as filler material and the

result obtained showed that there was

tempered martensite in the HAZ as well as

base metal [18].



A research was done on FSW weldments of

X-80 and concluded that the grain size of

HAZ region and the base metal was almost

same around 5 microns. Grain size increases

up to 30 micron as we advance towards

TMAZ. While in Fusion Welding coarse grain

are present. This shows that the conventional

coarse grain structure has moved to the

advancing side of TMAZ in FSW that were at

fusion line in Fusion Welding. The base metal

of X-80 steel contains ferrite, granular banite

and martensite while HAZ contains ferrite,

granular banite, and lath martensite. TMAZ

contain large fraction of granular banite,

degenerated upper banite and lath martensite.

Similar experiment was carried out for L-80

and observed that coarsening of carbide and

hard martensite were formed at the HAZ and

in TMAZ higher coarse grain of lath

martensite was formed while the base metal

contain mainly tempered carbides [19]. In

ferric stainless steel joined by FSW, due to

rapid cooling and high strain due to plastic

deformation the microstructure changed to

ferrite and martensite [12].

A research was done on low carbon steel to

see the effect of coarse initial grain size on

microstructure and as a result of increase in

heat input the microstructure in weld metal

changed from martensite and banite to grain

boundary ferrite, Widmanstatten ferrite,

acicular ferrite and pearlite. And HAZ

containing martensite, banite, pearlite and

polygonal ferrite changed to pearlite and

polygonal ferrite (as shown in figure 18). The

amount of pearlite has been formed with

decrease in martensite and banite also the

microstructure in the GCHAZ has refined

[21]. The study on intercritical HAZ showed

that the microstructure in fine grained

specimen transformed from grain boundary

ferrite and pearlite to polygonal ferrite, and in

coarse grain it changed from martensite to

ferrite and fine grain pearlite. The ferrite

changed to polygonal in original and coarse

grain specimen and pearlite grains tended to

refine [22]. The microstrucute of the HAZ in

low carbon steel depends on the chemical

composition, the peak welding temperature

and the welding voltage. The amount of

pearlite is inversely proportional to heat input

[23]. The welded region in high strength steel

contains acicular ferrite and pro eutectic ferrite

on boundary at low heat input while at higher

heat input the ferrite side is the main phase

[29].

(Refer figure 18)

In weldability study of Titanium Aluminide it

was found that the microstructural

characteristics of weldment were function of

welding speed, heat input and cooling rate. At

low welding speed (low cooling rate or high

heat input) fine acicular were formed and at

high welding speed (high cooling rate or low

heat input) β and ordered β were formed. The



microstructure in HAZ gradually varies from

fusion line to far HAZ [25].

The microstructure of GCHAZ in HSLA steel

showed that with decrease in heat input the

fraction of baintite increase and ferrite

decrease by volume. At 30 kJ/cm only fine

lathe bainite and at 60kJ/cm only granular

banite was formed [24]. In comparative study

between TIG, laser and TIG –laser hybrid

welding showed that only in TIGW transition

zone and HAZ were present [16].

4. Toughness

The ability of materials to absorb

energybefore fracture is called toughness. The

area under stress strain curve gives toughness.

Izod and Charpy test are most common

method to find toughness of material.

V notch Charpy impact test on HAZ was

carried for low alloy 16Mo3 and found that

MMA and MAG welded specimen has value

136 J and 89 J while that of base metal have

31 J, which means toughness has increased

after welding [27].

The charpy test carried on torr steel and Cu-

TMT bar suggest that SMAW joints on these

materials posses sufficient toughness at room

temperature and 00 C, but as the temperature

drops down below 00 C the steels are

susceptible to brittle fracture. CIT (Charpy

Impact Test) of torr steel for Parent Metal

show drop down from 117 J at 260C to 7.8 J at

00C, it shows high ductile -brittle transition in

the temperature range of 250 C. [5].

In friction stir welding of ferric steel the

toughness decreased in weld centre line (28 J)

and HAZ (30 J) compared to base metal (34 J)

[12].

The research was carried out in low carbon

steel SAE 1020 steel and SAE 1020 steel with

coarse initial grain size (CIG steel) for finding

toughness at different heat input showed that

maximum toughness at weld metal for both

steel were achieved with 1 kJ/mm due to

presence of tougher acicular ferrite. On the

other hand due to martensite formation at heat

input of 0.5 kJ/mm, minimum toughness was

obtained and there was small decrement in

weld metal at 2 kJ/mm due to coarsened phase

(figure 19 and 20). In the same way for HAZ it

was seen that maximum toughness of base

material was observed at 1 kJ/mm and for CIG

steel at 2 kJ/mm. The maximum toughness is

associated with ductile phase’s ferrite and

pearlite. The minimum toughness was

observed with heat input 0.5 kJ/mm. In CIG

steel compared to base metal the loss of

toughness is more due to high carbon

martensite formation [21]. The toughness of

steel can be controlled by varying welding

parameters. Toughness varied from 92.3 to

40.8 kJ as welding condition varied from

130A/20V to 180 A/30V as in figure 19 [23]

[30].

(Refer figure 19)

(Refer figure 20)



(Refer figure 21)

The toughness of PAW joints were 20 J

comparable to base metal (22 J) while of

PCGTAW and CCGTAW were less than base

metal and PAW joints. There was decrease in

SMAW by 18% and in GMAW by 27% [6]

[7].

Due to presence of martensite –austenite and

ferrite lath in banitic mixture in the GMA

weld zone of HSLA steel the toughness has

enhanced. But in FSW joints the presence of

martensite lowers the toughness [9]. The

charpy V notch test showed that toughness of

HAZ region matched with base material when

309L and 18-8-6 filler materials were used,

however toughness of joint made E309L filler

material was greater by factor of 3/2 [10].

The presence of nickel and austenite phase in

the weld metal leads to more toughness [15].

Due to auto tempering low carbon martensite

has higher toughness than upper banite [31].

The toughness of HSLA depend on

temperature and it increases almost linearly

with the heat increase in temperature as the

experiment showed variation from 55 J to 125

J when temperature changed from -50C to 00C

[32].

CONCLUSION

From the above study following conclusions

were drawn:

For ferrous as well as non ferrous

material there is decrease in tensile

strength when fusion welding (except

PAW) is employed.

FSW increases the tensile strength to

some extent.

Higher the ferrite content higher is the

Tensile strength.

The decrease in tensile strength

depends on the electrode material,

filler material, welding speed, heat

input.

The parent material and the welding

process decide whether failure will

occur in base material or weld zone.

Almost all experiment showed ductile

mode of failure.

In all the research the hardness of the

weld zone was greater, followed by

HAZ and base metal due to martensite

and banite formation.

Hardness increases with decrease in

heat input, also the hardness depend on

the composition of filler material.

The weld zone is wider for low speed

welding.

Martensite and banite is mainly present

in weld area and HAZ. The

microstructure transformation depends

on heat input. The amount of peralite is

inversely proportional to heat input.

The toughness of material is associated

with pearlite and ductile ferrite phases.

The filler material constituents also

decide the toughness of the welded



joints.

ACKNOWLEDGEMENT

Authors are thankful to Director, CSIR-

CIMFR, Dhanbad for his kind permission to

do the experimentation with reference to our

post-graduation research work and

publication thereof.

REFERENCES

[1]M. P. Groover, Fundamentals of Modern

Manufacturing, Wiley India Publication, 2010,

pp: 689-691

[2] R. K. Jain, Production Technology,

Khanna Publication, 17th Edition, 2013,

pp:273

[3] A. K. Lakshminarayanan, V.

Balasubramanian, K.Elangovan. Effect of

welding process on tensile properties of

AA6061 aluminium alloy joint, Int J Adv

Manuf Tech, 40 (2009), pp: 286-296

[4] Elsadig. Eltai, E. Mahdi, Akram Alfantazi.

The Effect of Gas Tungsten Arch Welding on

the Corrosion and Mechanical Properties of

AA6061 T6, Int. J. Electrochem. Sci., 8(2003),

pp: 7004-7015

[5] Rameen Datta, R.Veeraraghavan, K. L.

Rohiraa. Weldability Characteristic of Torr

and Corrosion- Resistant TMT Bar Using

SMAW Process, Journal of Material

Engineering and Performance, 11(2009), pp:

369-375

[6] A. K. Lakshiminarayanan, K Shanmugam,

V Balasubramanian. Effect of Autogenous Arc

Welding Processes on Tensile and Impact

Properties of Ferritic Stainless Steel Joints,

Journal of Iron and Steel Research, 16(1)

(2009), pp: 62-68

[7]A. K. Lakshiminarayanan, K Shanmugam,

V Balasubramanian. Effect of Welding

Processes on Tensile and Impact Properties,

Hardness and Microstructure of AISI 409M

Ferritic Stainless Steel Joints Fabricated by

Duplex Stainless Steel Filler Metal, Journal of

Iron and Steel Research,16(5) (2009), pp: 66-

72

[8] T. Mohandas, G. Madhusudhan Reddy,

Mohammad Naveed. A Comparative

evaluation of gas tungsten and shielded metal

arc welds of a “ferritic” stainless steel, Journal

of Material Processing Technology, 94(1999),

pp: 133-140

[9] S. RaguNathan, V. Balasubramanian, S.

Malarvizhi, A.G. Rao, Effect of Welding on

Mechanical and Microstructural Characteristic

of High Strength Low Alloy Naval grade Steel

Joints, Defence Technology,11(2015) , pp:

308-317



[10] G. Madhusudhan Reddy, T.Mohandas, G.

R. N. Tagore. Weldability studies of high-

strength low –alloy steel using austenitic

fillers,Journal of Material Processing

Technology, 49(1995), pp: 213-228

[11] P.Yayla, E. Kaluc, K.Ural. Effects of

welding processes on the mechanical

properties of HY 80 steel weldments.

Materials and Design, 28(2007), pp: 1898-

1906

[12] A. K. Lakshminarayanan,V.

Balasubramanian. An asseseement of

microstructure, hardness, tensile and impact

strength of friction stir welded ferritic stainless

steel joints, Material and Design, 31(2010),

pp: 4592-4600

[13] P. Sathiya, S. Aravindan, A. Noorul Haq.

Effect of friction welding parameters on

mechanical and metallurgical properties of

ferritic stainless steel, Int J Adv Manuf

Technol, 31(2007), pp: 1076-1082

[14] A-H. I. Mourad, A. Khourshid, T.Sharef.

Gas tungsten arc and laser beam welding

process effects on duplex stainless steel 2205

properties, Material Science and Engineering,

A 549 (2012), pp 105-113

[15] G Magudeeswaran, V Balasubramanian,

G madhusudhan Reddy, T S Balasubramanian.

Effect of Welding Processes and Consumables

on Tensile and Impact Properties of High

Strength Quenched and Tempered Steel Joints,

Journal of Iron and Steel Research, 15(6)

(2008), pp: 87-94

[16] Jun Yan, Ming Gao, Xiaoyan Zeng.

Study on microstructure and mechanical

properties of 304 stainless steel joints by TIG,

laser and laser- TIG hybrid welding, Optics

and Laser in Engineering, 48(2010), pp: 512-

517

[17] Zakaria Boumerzoung, Chemseddine

Defouf, Thierry Baudin. Effect of Welding on

Microstructure and Mechanical Properties of

an Industrial Low Carbon Steel. Engineering

(science research ), 2(2010), pp502-506

[18] C. Rodriguez, J. Garcia Cabeza, E.

Cardenas, F. J. Belzunce, C. Betengeon.

Mechanical Properties Characterization of

Heat- Affected Zone Using Small Punch Test,

Welding Journal, 88(sep 2009), pp: 188-s –

192-s

[19] A. Ozekcin, H. W. Jin, J. Y. Koo, N. V.

Bangaru, R.Ayer, G. Vaughn, R. Steel,

S.Packer. A Microstructural Study of Friction

Stir Welded Joints Of Carbon Steels,

Fourteenth International Offshore and Polar

Engineering Conference Toulon , France



2004, pp: 61-66

[20] Hakan Aydin. Relationship Between a

Bainitic Structure and the Hardness in the

Weld Zone of the Friction Stir Welded X80

API grade Pipe-line Steel, Material and

Technology, 48(2014), pp: 15-22

[21] M. Erglu, M. Aksoy, N. Orhan. Effect of

coarse initial grain structure on microstructure

and mechanical properties of weld metal and

HAZ of a low carbon steel, Material Science

and Engineering, A269(1999), pp: 59-66

[22] M. Erglu, M. Aksoy.Effect of coarse

initial grain size on microstructure and

toughness of intercritical Heat- affected zone

of a low carbon steel, Material Science and

Engineering, A286(2000), pp: 289-297

[23] Ehsan Gharibshahiyan, Abbas

Honarbakhsh Raouf, Nader Parvin, Mehdi

Rahimian. The effect of microstructure on

hardness and toughness of low carbon welded

steel using inert gas welding, Materials and

Design, 32(2011), pp: 2042-2048

[24] ZHANG Ying-qiao, ZHANG Han-qian,

LI Jin-fu, LIU Wei- ming. Effect of Heat Input

on Microstructure and Toughness of Course

Grain Heat Affected Zone in Nb Microalloyed

HSLA Steels, Journal of Iron and Steel

Research, 16(5) (2009), pp: 73-80

[25] S. A. David, J.A. Horton, G. M.

Goodwin, D. H. Phillips, R. W. Reed.

Weldability and Microstructure of a Titanium

Aluminide, Welding Research Supplement,

April 1990, pp: 133-s – 140-s

[26] G. M. Goodwin, N. C. Cole, G. M.

Slaughter. A study of Ferrite Morphology in

Austentic Stainless Steel Weldment, Welding

Research Supplement, September 1972, pp:

425-s – 429-s

[27] Belma Fakic, Adisa Buric, Branka

Muminovic, Sreto Tomasevic.Change of

Physical – Metallurgical Properties of Low-

Alloy Steel 16Mo3 in the Heat Affected Zone

in Welding Processes MMA and MAG,15th

International Research/ Expert Conference

“Trends in Development of Machinery and

Associated Technology ”, Prague Czech

Republic, 2011, pp: 129-132

[28] J.W. Elmer,J.wong, T.Ressler and T.A.

Palmer,6th International conference on Trends

in Welding Research, pine mountain, 6A

April, pp: 15-19

[29] Wang Juan, LI Yajiang. Microstructure

characterization in the weld metal of HQ130 +

QJ63 high strength steels, Bull. Mater. Sci, vol

26 No 3,April 2003, pp: 295-299



[30] Millian Karl, Datta Ratan, Zimmermann

Horst. Effects off heat input on the

microstructure and toughness of 8MnMoNi 5

5 shaped- welded nuclear steel. J Nucl Mater,

340 (2005), pp: 25-32

[31] C. Thaulow, A. J. Paaw, K. Guttormsen.

The Heat Affected Zone Toughness of Low

Carbon Microalloyed Steels, Welding

Research Supplement, September 1987, pp:

266-s – 279-s

[32] Ritter JC, Dixon BF. Improved properties

in welded HY-80 steel for Australian warship.

Welding J,66(3) (1987),pp: 33-44



LIST OF TABLES

Table 1: Tensile property for welded and un-welded specimen of AA6061 T6 [4].

Table 2: Hardness value for welded specimen[4].



LIST OF FIGURES

Figure 1: Stress – Strain relationship for welded and un-welded specimen of AA6061 T6alloy [4].

Figure 2: Load vs. displacement curves of Parent Metal and welded joints [9].



Figure 3: Hardness profile for welded area and away from the weld [4].

Fig 4: Hardness profile of torr steel [5]. Fig 5: Hardness profile of Cu TMT steel

[5].

Figure 6: Hardness measurement on surface across the weld metal of industrial low carbon steel [17].



Figure 9: Hardness profile of friction stir welded 409M ferritic stainless steel [12].



Figure10: Hardness measurement result with heat input a) 0.5, b) 1 c) 2 kJ/mm [21].

Specimen 1 SAE 1020 steel (base metal)

Specimen 2 SAE 1020 steel with coarse initial grain size

Figure11: Relationship between hardness value of intercritical HAZ and heat input [22].



Figure 12: Hardness value across weld in ferric stainless steel due to different welding process [6][7].

Figure 13: Hardness profile of HSLA using a) 309L filler b) 18-8-6 filler [10].



Figure 14: Microhardness variation of Titanium aluminide Electron Beam weldments made at three

welding speeds and heat inputs [25].

Figure 15: Microstructure of different zone for a) MMA joints b) MAG joints [27].



Figure 16: Microstructure of HAZ after welding of an industrial low carbon steel [17].

Figure 17: Center of weld metal “in the weld fusion zone”[17].

Figure 18: The formation of microstructure in GCHAZ in SAE 1020 steel with coarse initial grain

size for a heat input 0.5 kJ/mm [21].



Figure 19: Variation of temperature with current and voltage [23].

Figure 20: Relationship of weld metal toughness vs heat input (B, base metal) [21].

Figure: 21Relationship between toughness of HAZ and heat input (B,base metals) [21].

THE EFFECT OF WELDING ON MECHANICAL AND …...The difference between Vickers and Knoop is that the...

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