INVESTIGATION OF MIG WELDING TO THE CORROSION ...

INVESTIGATION OF MIG WELDING TO THE CORROSION BEHAVIOUR OF

CARBON STEEL

NG WAI LOON

Report submitted in partial fulfilment of the requirements for the award of the degree of

Bachelor of Mechanical Engineering

Faculty of Mechanical Engineering

UNIVERSITI MALAYSIA PAHANG

JUNE 2012

vii

ABSTRACT

A welding process was performed on the low carbon steel based on different welding

parameters in this experiment. The main objective of this study was to investigate the

effect of welding voltages (19 V, 20 V, 21 V, and 22 V) and wire feed rates (90 ipm,

100 ipm, 110 ipm, and 120 ipm) to the corrosion behaviour of welded carbon steel in

synthetic seawater environment (3.5 wt% NaCl). Besides that, the microstructure

changes in the weldments of maximum and minimum voltages were analysed and

compared with the as-received sample before welding process. On the other hand, the

penetration level of the weldments was analysed due to the different welding parameter.

The welding method in this experiment was metal inert gas (MIG) with filler metal (ER

70S-6 with 1.2 mm diameter). Based on the results obtained, the corrosion rate

decreased when the welding voltage was increased from 19 V to 22 V or when the wire

feed rate was increased from 90 ipm to 120 ipm until the full penetration level of

weldment occurred. In conclusion, the lowest corrosion rate occurred at highest welding

voltage and highest wire feed rate when full penetration of weldment occurred. The

corrosion product that formed on the surface of the sample was iron oxides and pitting

was found on the surface of the exposed area after the corrosion test.

viii

ABSTRAK

Satu proses kimpalan telah dijalankan ke atas keluli karbon rendah berdasarkan

beberapa parameter kimpalan yang berlainan dalam eksperimen ini. Objektif utama bagi

kajian ini adalah untuk mengkaji kesan voltan kimpalan (19 V, 20 V, 21 V dan 22 V)

dan kadar suapan wayar (90 ipm, 100 ipm, 110 ipm, and 120 ipm) kepada kelakuan

kakisan kimpal dalam persekitaran air laut sintetik (3.5wt % NaCl). Selain itu,

perubahan mikrostruktur dalam hasil kimpal voltan maksimum dan minimum telah

dianalisis dan dibandingkan dengan sempel yang diterima sebelum proses kimpalan. Di

samping itu, tahap penembusan daripada hasil kimpal yang disebabkan oleh parameter

kimpalan berbeza dianalisis. Kaedah kimpalan dalam eksperimen ini adalah

menggunakan mesin kimpalan MIG (metal inert gas) dengan logam pengisi (ER 70S-6

berdiameter 1.2 mm). Berdasarkan keputusan yang diperolehi, kadar kakisan akan

menurun apabila voltan kimpalan meningkat dari 19 V ke 22 V dan kadar suapan wayar

meningkat dari 90 ipm ke 120 ipm sehingga tahap penembusan penuh hasil kimpal

terjadi. Kesimpulannya, kadar kakisan terendah berlaku pada voltan kimpalan dan kadar

suapan wayar yang tertinggi ketika penembusan penuh kimpal berlaku. Hasil kakisan

yang terbentuk di permukanan sampel adalah oksida besi dan bopeng telah dijumpai di

permukaan kawasan yang terdedah selepas ujian kakisan.

ix

TABLE OF CONTENTS

Page

EXAMINER DECLARATION ii

SUPERVISOR’S DECLARATION iii

STUDENT’S DECLARATION iv

DEDICATION v

ACKNOWLEDGEMENTS vi

ABSTRACT vii

ABSTRAK viii

TABLE OF CONTENTS ix

LIST OF TABLES xiii

LIST OF FIGURES xiv

LIST OF SYMBOLS xvii

LIST OF ABBREVIATIONS xviii

CHAPTER 1 INTRODUCTION

1.1 Introduction 1

1.2 Background of Study 1

1.3 Problem Statement 3

1.4 Objectives 4

1.5 Scopes 4

1.6 Thesis Outline 4

CHAPTER 2 LITERATURE REVIEW

2.1 Introduction 6

2.2 Material 7

2.2.1 Carbon Steel 7

2.2.2 Types of Carbon Steel 7

2.2.3 Application of Carbon Steel in Seawater 9

2.2.4 Welding Wire 10

2.3 Corrosion Concepts 11

2.4 Electrochemical Corrosion Measurement 13

x

2.5 Types of Corrosion 16

2.5.1 Galvanic Corrosion 16

2.5.2 Stress Corrosion Cracking (SCC) 17

2.5.3 Hydrogen-induced Cold Cracking 18

2.5.4 Pitting 19

2.6 Factors Influencing Corrosion of Weldments 20

2.6.1 Welding Factors 20

2.6.2 Metallurgical Factors 22

2.7 Weld Microstructures 23

2.7.1 The Fusion Zone 24

2.7.2 Heat Affected Zone (HAZ) 25

2.7.3 Base Metal 26

2.8 Effect of Heat Input on Low Carbon Steel 27

2.8.1 Weld Microstructure 27

2.8.2 Geometrical Factors 35

CHAPTER 3 METHODOLOGY

3.1 Introduction 38

3.2 Material 40

3.3 Sample Preparation 41

3.4 Compositional Analysis 41

3.5 Welding 43

3.6 Metallorgraphic Analysis 45

3.7 Electrochemical Test 55

3.8 Scanning Electron Microscopy (SEM) 57

CHAPTER 4 RESULTS AND DISCUSSION

4.1 Introduction 59

4.2 Compositional Analysis 60

4.3 Microstructural Examination of As-Received Sample 61

4.4 Optical Microscopy of Welded AISI 1010 Carbon Steel 63

4.5 Visual Inspection of Welded AISI 1010 Carbon Steel 65

4.6 Polarization Results of Electrochemical Test 69

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4.7 Effect of Welding Voltage and Wire Feed Rate on Corrosion Rate 77

4.7.1 Effect of Wire Feed Rate on Corrosion Rate 78

4.7.2 Effect of Welding Voltage on Corrosion Rate 79

4.8 Scanning Electron Microscopy (SEM) Result 82

CHAPTER 5 CONCLUSION AND RECOMMENDATIONS

5.1 Introduction 85

5.2 Conclusions 85

5.3 Recommendations 86

REFERENCE 87

APPENDICES

A1 AISI-SAE Standard Carbon Steels 90

A2 Compositional Analysis of Sample Material 91

B Sample Calculation of Corrosion Rate for Electrochemical Test 92

C1 Optical Microscopy of Welded Sample 1 93
















D1 Visual Inspection of Welded Samples 1, 2, 3 and 4 109

xii




E1 Gantt Chart PSM 1 113

E2 Gantt Chart PSM 2 114

xiii

LIST OF TABLES

Table No. Page

2.1 Types of carbon steel 8

2.2 Chemical composition of AWS ER70S-6 10

3.1 Welding parameter 45

3.2 Parameter setup in electrochemical test 56

4.1 Composition analysis of AISI 1010 carbon steel 60

4.2 Visual inspection of welded AISI 1010 carbon steel 66

4.3 Tafel polarization curve data of samples 1, 2, 3 and 4 (19 V) 70




4.7 Corrosion rate of samples with different wire feed rate and welding

voltages

77

xiv

LIST OF FIGURES

Figure No. Page

2.1 The basic corrosion cell 11

2.2 Corrosion process showing anodic and cathodic current components 14

2.3 Schematic diagrams showing the regions of a heterogeneous weld 23

2.4 Variation of weld structure with distance from the welding seam

centre

24

2.5 Iron-carbon phase diagram 27

2.6 Weld microstructure in low carbon steels 30

2.7 Continuous cooling transformation diagrams for weld metal of low

carbon steel

30

2.8 Weld microstructure in low carbon steels 31

2.9 HAZ microstructure in low carbon steels 32

2.10 Base metal microstructure in low carbon steels 32

2.11 Weld microstructure with heat input 1 (690 J/mm) 33

2.12 Weld microstructure with heat input 4 (2800 J/mm) 34

2.13 Effect of percentage of heat input to the corrosion current of weld

metal

34

2.14 Weld bead geometry 36

2.15 Effect of welding voltage on bead geometry 37

2.16 Effect of wire feed rate on bead geometry 37

3.1 A flow chart showing a summary of the research methodology 39

3.2 Photograph of carbon steel in laboratory 40

3.3 Shearing machine (MSV-C 31/6) 40

3.4 Sample preparation for welding process 41

3.5 Spectrometer machine 42

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3.6 Sample 17 (as-received material) 42

3.7 MIG welding machine 43

3.8 (a) Carbon dioxide cylinders and (b) Filler material

(AWS ER 70S-6)

44

3.9 Welded sample 44

3.10 Sectional cut-off machine 46

3.11 Sample after cutting process 46

3.12 Sample after connected with wire 47

3.13 Voltmeter 47

3.14 LECOSET 7007 (resin and liquid) 48

3.15 Mounting cup 49

3.16 LECOMAT pressure vessel 49

3.17 Sample 5 50

3.18 Grinding machine 51

3.19 Rotating polishing wheel 52

3.20 (a) 6 micron diamond suspension and (b) 1 micron diamond

suspension

52

3.21 0.05 micron alumina suspension 53

3.22 Etching solution 53

3.23 Optical microscope 54

3.24 A schematic diagram showing weldment, base metal and HAZ 54

3.25 Electrochemical measurement setup 56

3.26 WPG-100 potentiostat 57

3.27 Cleaning solution 58

3.28 Cleaning process 58

4.1 Sample 17 (as-received material): (a) Top view and (b) Bottom view 61

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4.2 Optical micrograph of as-received AISI 1010 carbon steel (500x

Magnification)

62

4.3 Optical micrograph of weldment sample 4 (19 V and 120 ipm)

(500x Magnification)

63

4.4 Optical micrograph of weldment sample 16 (22 V and 120 ipm)

(500x Magnification)

64

4.5 Sample 13 (22 V and 90 ipm) 67

4.6 Sample 14 (22 V and 100 ipm) 67

4.7 Sample 16 (22 V and 120 ipm) 68

4.8 Polarization diagram of sample 1, 2, 3 and 4 (19 V) 69

4.9 Graph of corrosion rate versus wire feed rate of samples 1, 2, 3 and 4 71

4.10 Polarization diagram of sample 5, 6, 7 and 8 (20 V) 71

4.11 Graph of corrosion rate versus wire feed rate of samples 5, 6, 7 and 8 73

4.12 Polarization diagram of sample 9, 10, 11 and 12 (21V) 73

4.13 Graph of corrosion rate versus wire feed rate of samples 9, 10, 11

and 12

75

4.14 Polarization diagram of sample 13, 14, 15 and 16 (22V) 75

4.15 Graph of corrosion rate versus wire feed rate of samples 13, 14, 15

and 16

77

4.16 Graph of corrosion rate versus wire feed rate 78

4.17 Graph of corrosion rate versus welding voltages 79

4.18 Sample 15 before cleaning process 82

4.19 Sample 15 after cleaning process 83

4.20 Corrosion product formed after corrosion test 83

4.21 Corrosion defect after corrosion test 84

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LIST OF SYMBOLS

A Exposed area

d Density

Ecorr Corrosion potential

Eoc Open circuit potential

I Welding current

Icorr Corrosion current

K Constant value

Q Heat input

S Welding speed

V Welding voltage

% Percentage

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LIST OF ABBREVIATIONS

AISI American Iron and Steel Institute

ASTM American Society for Testing and Materials

Ar Argon

C Carbon

CO2 Carbon dioxide

Cr Chromium

CR Corrosion rate

Cu Copper

e- Electron

EW Equivalent weight

Fe Iron

Fe2+

Ferrous ions

Fe3+

Ferric ions

Fe2O3·nH2O Iron (III) oxides

FeO(OH) Iron (III) oxide-hydroxide

Fe(OH)3 Iron (III) oxide-hydroxide

FHWA Federal Highway Administration

GMAW Gas Metal Arc Welding

HAZ Heat affected zone

HCL Acid hydrochloric

H2O Water

MIG Metal inert gas

Mn Manganese

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Mo Molybdenum

NACE National Association of Corrosion Engineers

NaCl Sodium chloride

Ni Nickel

No Number

O2 Oxygen

OH- Hydroxide irons

P Phosphorus

S Sulphur

SAE Society of Automotive Engineers

SCC Stress corrosion cracking

SEM Scanning electron microscopy

Si Silicon

UMP University Malaysia Pahang

V Vanadium

Wt% Weight percentage

CHAPTER 1

INTRODUCTION

1.1 INTRODUCTION

This chapter explains about the background of study, problem statement,

objectives, and scopes of this study. The purpose of this study can be identified by

referring at the problem statement of this study. Besides that, the detail of the study and

output can be obtained based on the objectives and scopes of this study.

1.2 BACKGROUND OF STUDY

Corrosion can be defined as degradation of quality and properties in a material

due to the chemical reaction between the components of the material and the

surrounding. In other words, corrosion can be described as deterioration of essential

properties such as mechanical properties and physical properties in a material (Seifedine,

2008). Corrosion can cause a variety of problems in our daily life, depending on the

application of the metals. The first common problem is the leakage of the metal such as

tanks and pipes, which allows leakage of fluids or gases out of the tanks or pipes.

Metals are widely used in the piping system either in underground or seawater condition

which corrosion is easily occurred. Besides that, the next effect of corrosion is the

degradation of quality and properties in a material. The strength of the metal where the

cross section of structural members is reduced due to the effect of the corrosion, leading

to a loss of strength of the structure and subsequent failure of the structures.

Millions of dollars are lost each year due to the effect of corrosion. Much of this

loss is due to the corrosion of iron and steel since the price of iron and steel is much

2

more expensive and both metals are widely used in the industry compared to other type

of metals (Osarolube et al., 2008). Based on the study entitled “Corrosion Costs and

Preventive Strategies in the United States”, the total annual estimated direct cost of

corrosion in the United State is a staggering $276 billion. Besides that, the indirect

corrosion costs are lost time, and thus lost productivity because of outages, delays,

failures, and litigation. The shipping industry cost of corrosion is $2.7 billion, broken

down into new ship construction ($1.1 billion), maintenance and repairs ($0.8 billion),

and corrosion-related downtime ($0.8 billion) (Koch et al., 2002).

Carbon steel is the most widely used engineering material despite its relatively

limited corrosion resistance. Carbon steel is used in large tonnages in marine

applications, nuclear power and fossil fuel power plants, transportation, chemical

processing, petroleum production and refining, pipelines, mining, construction and

metal-processing equipment. Carbon steel has been the most widely used structural

material which is abundantly available, inexpensive and has adequate mechanical

properties but has a high general corrosion rate (Kadhim, 2011).

Welding is a reliable and efficient metal-joining process which is widely used in

the industry. With the growing emphasis on the use of automated and robotic system

Metal Inert Gas (MIG) welding, with its all-position capabilities, Gas Metal Arc

Welding (GMAW) has been employed increasingly in mechanized surfacing in the

industry (Murugan and Parmar, 1994). However, during the welding process, due to the

different quantity of heat input as well as the quality of the weldments, many problems

arise from the process especially in corrosion (Funderburk, 1999). The cycle of heating

and cooling that occurs during the welding process affects the microstructure and

surface composition of welds and adjacent base metal. Metallurgical factor is one of the

primary concerns to the corrosion of welded carbon steel (Davis, 2006). Thus, the joint

is always considered as the weakest part of a component.

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1.3 PROBLEM STATEMENT

Carbon steel is the most widely used engineering material in the overall of steel

production worldwide. Although carbon steel is highly related to the limited corrosion

resistance compared to other common types of steels such as stainless steel, carbon steel

is still used in large tonnages in applications which are highly related to the high

corrosion resistance requirement. Since carbon steels represent the largest single class

of alloys in use, both in terms of tonnage and total cost, it is easy to understand that the

corrosion of carbon steels is a problem of enormous practical importance. This is the

reason for the existence of entire industries devoted to providing protective systems for

irons and steel.

Carbon steels are commonly used in seawater for structural applications such as

ship hulls, offshore platforms, sheet piles and coastal facilities as well as sea water

piping systems. Millions of dollars are lost each year due to the effect of corrosion, thus

the corrosion behaviour of carbon steel is utmost important to be studied. Previously,

study of corrosion of welded carbon steels in seawater is always related to the type of

material used. However, welding parameters such as welding voltages applied and wire

feed rate play a big role in influencing the corrosion rate of the steel. Welding

parameters have a high influence on the quality of the welding which directly affects the

corrosion resistance of the material. Besides that, welding parameters have high

influence on the heat input to the material which directly alter the microstructure of the

weldments and indirectly affects the corrosion rate of the material. Although there are

many researches and studies about the corrosion of welded carbon steel carried out in

the past few decades in seawater environment, there is still no research came out which

accurately describes the trend of corrosion rate to welding parameters. Thus, in this

study, the effect of welding parameters on the corrosion rate of welded carbon steel in

seawater environment is investigated.

4

1.4 OBJECTIVES

The main objective of this study is to investigate the effect of welding voltage

and wire feed rate to the corrosion behaviour of weld carbon steel in synthetic seawater

environment.

1.5 SCOPE

i) The material used is low carbon steel (AISI 1010).

ii) The welding method employed is MIG.

iii) Different welding voltages (19 V, 20 V, 21 V, and 22 V) and wire feed rates

(90 ipm, 100 ipm, 110 ipm, and 120 ipm) are used to join the sample using

butt joints.

iv) Microstructure analysis of welding specimens by using optical microscope/

scanning electron microscopy (SEM).

v) Electrochemical test by using potentiostat.

vi) Corrosion rate of welded carbon steel in synthetic seawater (3.5 wt% NaCl)

environment.

1.6 THESIS OUTLINE

This thesis consists of 5 chapters which illustrate the flow of the project from

introduction till the conclusion. Every chapter presents with different contents. After

read the entire chapters in the thesis, the viewer may understand the detail of the project

and obtains the output of the project.

Chapter 1 contains about the background of study, problem statement, objectives,

and scopes of this study.

Chapter 2 contains all the literature review and some presentation of the earlier

work. This chapter also presents about the information of the material that used in this

study. Some concepts which relate to the corrosion also discusses in this chapter.

5

Chapter 3 contains the summary of the research methodology of this project.

This chapter also explains about the flow of the project which includes the steps of

project conducted.

Chapter 4 contains the results that obtained during this study. This chapter also

explains the analysis and discussion of the result. The result obtained is discussed and

compared to previous study in this chapter.

Chapter 5 explains the conclusion of the project. This chapter also includes the

future recommendation of the project.

CHAPTER 2

LITERATURE REVIEW

2.1 INTRODUCTION

This chapter presents about the material that used in this study which includes

type of material and some basic knowledge about the chosen material and the

application of the material in seawater environment. On the other hand, some concepts

which relate to the corrosion include the electrochemical reaction also discusses in this

chapter. The formation of the corrosion product also explains in this chapter based on

the chemical reaction. The corrosion determination method that used in this study which

is polarization diagram and some formula which relate to the corrosion determination

also include in this chapter. Different types of corrosion defects which relate to welding

also discuss in this chapter such as stress corrosion cracking (SCC), pitting and galvanic

corrosion. Besides that, this chapter also explains about the history background and

presentation of the earlier work.

7

2.2 MATERIAL

2.2.1 Carbon Steel

Carbon steel is the most widely used engineering material in the overall of steel

production worldwide (Morrow, 2010). Carbon steel can be defined as steel where the

main interstitial alloying element is carbon. Carbon steel can be described as the

structural material which is abundantly available, inexpensive, adequate formability and

weldability, and has adequate mechanical properties but has a high general corrosion

rate (Kadhim, 2011).

Although carbon steel is always related to the low corrosion resistance or high

general corrosion rate, it is still the most widely used engineering material in this world.

It is well known that carbon steel corrodes rapidly in seawater environment and requires

adequate protection depending on the type of application. Though carbon steel is the

most prone to corrosion, it is the least expensive of the most commonly perforated

metals compared to other type of structural material. Carbon steel is used in large

tonnages in marine applications, nuclear power and fossil fuel power plants,

transportation, pipelines, mining, and construction (Kadhim, 2011).

2.2.2 Types of Carbon Steel

Carbon steel can be divided into five groups based on its carbon content which

are low carbon steel, mild steel, medium carbon steel, high carbon steel and ultra-high

carbon steel. Typical groups of carbon steels are as tabulated in Table 2.1 and each

group of carbon steel is provided with some examples which start with American Iron

and Steel Institute (AISI). There are a total of five groups of carbon steel which shows

different characteristics as discussed in Table 2.1. Different groups of carbon steel are

applied in different application in worldwide and it depends on the characteristic of the

carbon steel and the requirement of the application.

8

Table 2.1: Types of carbon steel

Carbon

steel types

Example

AISI No.

% of

carbon

Explanation

Low carbon

steel

1010, 1012 0.05-0.15 It is neither ductile nor brittle.

It is normally used when huge

quantities of steel and high surface

finish are required.

It is used in the form of structural

steel such as sheets, strips, rods and

wires.

Mild steel 1018, 1020 0.16-0.29 Its price is usually low and it

provides the material properties

which are acceptable under many

circumstances.

It is characterized by a low tensile

strength, but it is malleable, good

machinability, and cheap

It is used to produce ship plates,

welded turbines, boiler tubes and

camshafts.

Medium

carbon steel

1035, 1038 0.30-0.59 It is stronger and possesses better

hardness and tensile strength but less

ductility than mild steel.

It has good machinability, deep

hardening properties and fantastic

wear resistance.

It is used in automotive components

which required higher strength such

as stronger nut, large forgings, and

high tensile tubes.

High carbon

steel

1055 0.6-0.99 It is very strong, utilized in high-

strength wires and springs.

Ductility and machinability of steel

decreases with the increase in carbon

content.

It is used in produce cold chisel,

wrenches, jaws, hacksaw blades and

railway service.

Ultra-high

carbon steel

1-2 It could be tempered for greater

hardness.

It is utilized for special purposes

such as non-industrial-purpose

knives, punches or axles.

Source: Ashby and Johnson (2009)

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2.2.3 Application of Carbon Steel in Seawater

Although carbon steel is highly related to the limited corrosion resistance

compared to other common types of steels such as stainless steel, carbon steels are

commonly used in seawater for structural applications such as ship hulls, offshore

platforms, sheet piles and coastal facilities as well as seawater piping systems. All these

applications required high corrosion resistance material since the medium environment

of the applications is seawater which can increase the corrosion rate of the material

(Kadhim, 2011). Basically, seawater in the ocean in the world has a salinity which is

about 3.5 %. In other words, each litre by volume of seawater has approximately 35

grams of dissolved salts (predominantly sodium (Na+) and chloride (Cl

−) ions).

Carbon steel is preferred in a seawater environment compared other types of

material since carbon steel exhibit low initial cost compared with other materials, the

ready availability of material and components and the existence of widely used and

accepted welding procedures. However, the rate of corrosion of carbon steel is much

higher and this becomes the main barrier of the usage of carbon steel in seawater

environment. Basically, a system that produced or designed using carbon steel is much

cheaper since carbon steel is inexpensive but the system is larger, heavier and shorter

life compared to other structural material. Thus, the failures of the structure may occur

earlier and it is within a few years and complete replacement is required compared to

other better corrosion resistance structural material (Bennett, 2002).

However, in order to increase the corrosion resistance of carbon steel in

seawater environment, method of coatings is largely applied. Coating is a famous and

widely used method to protect the low corrosion resistance material such as plain

carbon steel but it also increases the initial costs since more process is needed compared

to plain carbon steel. Coating is applied on the both surfaces which are inner and outer

surface in order to increase the corrosion resistance of the material. However, by

applying a coating on the surface of the material, it introduces complications into the

fabrication procedures, such as the need for a local removal prior to welding and re-

application afterwards (Morrow, 2010). Besides that, heat treated carbon steel can be

used compared to plain carbon steel in order to improve the corrosion resistance of the

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carbon steel. Heat treated carbon steel has better mechanical properties and corrosion

resistance compared to the plain carbon steel since different microstructure existed in

the material.

2.2.4 Welding Wire

In MIG welding, AWS ER70S-6 is a common wire types that used to join the

common steel. AWS ER70S-6 is a mild steel welding wire that contains a higher

percentage of manganese and silicon compared to other standard grades of MIG wire.

This welding wire is chosen in order to produce high quality welds when used on dirty,

oily, or rusty steel. The chemical composition of AWS ER70S-6 is shown in Table 2.2.

High percentage of silicon content increases the fluidity of the weld pool which create a

smoother bead appearance and resulting in minimal post-weld grinding. This wire is

engineered to provide trouble-free performance from heavy duty, high speed, spray

transfer applications all the way to light duty low speed, short-arc applications. ER70S-

6 is designed for use with various gas mixtures such as 100 % CO2, 75 %/25 % Ar/CO2

or 98 %/2 % Ar/O2 (Scholz, 1996).

Table 2.2: Chemical composition of AWS ER70S-6

Source: Scholz (1996)

Element Weight, %

C 0.06 to 0.15

Si 0.8-1.15

Ni 0.15 (max)

Mo 0.15 (max)

Cu 0.5 (max)

S 0.035 (max)

Cr 0.15 (max)

Fe Balance

Mn 1.40-1.85

V 0.025 (max)

P 0.03 (max)

Other 0.5 (max)

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