UNIVERSITI TEKNIKAL MALAYSIA MELAKA
THE EFFECTS OF METAL INERT GAS (MIG) PROCESS
CONDITION ON HARDNESS OF STAINLESS STEEL CLADDINGS
OF A CARBON STEEL SUBSTRATE
This report submitted in accordance with requirement of the Universiti Teknikal
Malaysia Melaka (UTeM) for the Bachelor Degree of Manufacturing Engineering
(Manufacturing Process)
by
AZRI SAFWAN BIN ABDUL HALIM
B050710249
FACULTY OF MANUFACTURING ENGINEERING
2011
UNIVERSITI TEKNIKAL MALAYSIA MELAKA
BORANG PENGESAHAN STATUS LAPORAN PROJEK SARJANA MUDA
TAJUK: The Effects of Metal Inert Gas (MIG) Process Condition on Hardness of Stainless Steel Claddings of Carbon Steel Substrate
SESI PENGAJIAN: 2010/11 Semester 2 Saya AZRI SAFWAN BIN ABDUL HALIM mengaku membenarkan Laporan PSM ini disimpan di Perpustakaan Universiti Teknikal Malaysia Melaka (UTeM) dengan syarat-syarat kegunaan seperti berikut:
1. Laporan PSM adalah hak milik Universiti Teknikal Malaysia Melaka dan penulis. 2. Perpustakaan Universiti Teknikal Malaysia Melaka dibenarkan membuat salinan
untuk tujuan pengajian sahaja dengan izin penulis. 3. Perpustakaan dibenarkan membuat salinan laporan PSM ini sebagai bahan
pertukaran antara institusi pengajian tinggi.
4. **Sila tandakan (√)
SULIT
TERHAD
TIDAK TERHAD
(Mengandungi maklumat yang berdarjah keselamatan atau kepentingan Malaysia yang termaktub di dalam
AKTA RAHSIA RASMI 1972)
(Mengandungi maklumat TERHAD yang telah ditentukan
oleh organisasi/badan di mana penyelidikan dijalankan)
Alamat Tetap: No 16, JALAN AU 1C/3K
TAMAN KERAMAT PERMAI
54200 KUALA LUMPUR
Tarikh: _________________________
Disahkan oleh:
PENYELIA PSM
Tarikh: _______________________
** Jika Laporan PSM ini SULIT atau TERHAD, sila lampirkan surat daripada pihak berkuasa/organisasi berkenaan dengan menyatakan sekali sebab dan tempoh laporan PSM ini perlu dikelaskan sebagai
SULIT atau TERHAD.
APPROVAL
This report is submitted to the Faculty of Manufacturing Engineering of UTeM as
a partial fulfillment of the requirements for the degree of Bachelor of
Manufacturing Engineering (Manufacturing Process). The members of the
supervisory committee are as follow:
………………………………
Main Supervisor
(Dr. Nur Izan Syahriah Binti Hussein)
(Official Stamp)
DECLARATION
I hereby, declared this report entitled “The Effects of Metal Inert Gas (MIG) Process
Condition on Hardness of Stainless Steel Claddings of a Carbon Steel Substrate” is the
results of my own research except as cited in references.
Signature : ……………………………....
Author’s Name : Azri Safwan Bin Abdul Halim
Date : 18 May 2011
i
ABSTRACT
An experimental research titled “The effect of MIG process conditions on hardness
of stainless steel claddings of a carbon steel substrate” has been carried out. The
overall aim is to investigate how different deposition parameters affected
macrostructure, microstructure and hardness variation of stainless steel deposited
material. The cladding process will be conducted using metal inert gas (MIG) weld
method. Background knowledge about metal deposition including form of materials,
heat sources and its commercial application in relation to its cladding, process
parameter, microstructure properties, hardness variation, and macrostructure also
reviewed. This experimental method involves manipulating one variable (cladding
parameter) to determine if changes in this variable cause changes in another variable
(hardness variation). This method relies on controlled methods and the manipulation
of variables to test a hypothesis. Finally, the hardness variation of cladding stainless
steel was inspected using Rockwell test. In addition, Design Expert Software that
implemented response surface methodology technique has been used in order to
make sure the optimization of parameters while conducting this experimental
research. This research had successfully analyzed the data collected from this
experimental research. The effect of welding parameters such as current, voltage and
travel speed are directly affected hardness variations of carbon steel cladding
material. Finally, the suggestion to enhance the optimization of parameter in cladding
process also had been discussed.
ii
ABSTRAK
Sebuah penelitian eksperimental berjudul "Pengaruh keadaan proses MIG pada
kekerasan kelongsong stainless steel dari substrat baja karbon" telah dilakukan.
Objektif umumnya adalah untuk menyiasat bagaimana parameter deposisi yang
berbeza berpengaruh macrostructure, mikro dan variasi kekerasan disimpan bahan
stainless steel. Proses cladding akan dilakukan menggunakan logam inert gas (MIG)
kaedah las. Latar belakang pengetahuan tentang pengendapan logam termasuk dalam
bentuk bahan, sumber panas dan aplikasi komersil dalam hubungannya dengan
cladding nya, parameter proses, sifat mikro, variasi kekerasan, dan macrostructure
juga disemak. Kaedah eksperimen melibatkan memanipulasi satu variabel (parameter
cladding) untuk menentukan sama ada perubahan ini menyebabkan perubahan
pembolehubah dalam pembolehubah lain (variasi kekerasan). Kaedah ini bergantung
pada kaedah dikendalikan dan manipulasi pembolehubah untuk menguji hipotesis.
Akhirnya, variasi kekerasan cladding stainless steel diperiksa menggunakan uji
Rockwell. Selain itu, Ahli Design Software yang respon permukaan teknik
dilaksanakan metodologi telah digunakan dalam rangka untuk memastikan
pengoptimuman parameter ketika melakukan kajian eksperimental. Penyelidikan ini
telah berjaya menganalisis data yang dikumpul daripada kajian ini eksperimental.
Pengaruh parameter pengelasan seperti arus, voltan dan kelajuan perjalanan secara
langsung terkena kesan variasi kekerasan baja karbon cladding material. Akhirnya,
cadangan untuk meningkatkan optimasi parameter dalam proses cladding juga telah
dibincangkan.
iii
DEDICATION
For my beloved family:
Abdul Halim Bin Mohd Salleh
Siti Sabariah Binti Muhammad Syariff
For my adored friends:
Muhammad Rabani Bin Othaman
Amzar Bin Mat Yunus
Azhar Bin Abdol Aziz
Muhammad Aiman Bin Yusof
Muhd Ammar Bin Hassan
Syukri Zarizi Bin Kamaruzan
Muhammad Ikhwan Bin Muhammad
Kamarul Syaufi Bin Rasidi
BMFP’s Students
iv
ACKNOWLEDGEMENT
Alhamdulillah and thank to Allah S.W.T. with all His Gracious and His Merciful for
giving me strength and ability to accomplish this project research successfully. I
would like to take the utmost opportunity to express my sincere and gratitude to my
supervisor, Dr. Nur Izan Syahriah Binti Hussein who is always giving me supports
and guidance throughout the semester in completing this ‘Projek Sarjana Muda’.
Besides, thanks a lot to all lecturers and staffs of Faculty of Manufacturing
Engineering.
Also with the greatest thanks to my beloved parents and family who always pray and
give the encouragement while pursuing my research and project. Their sacrifices are
never being forgotten.
Finally, to all my fellow friends who involves direct or indirectly that always stand
strong beside me in giving opinions and supports throughout our relationship, I really
thankful and appreciate it.
v
TABLE OF CONTENT
Abstract i
Abstrak ii
Dedication iii
Acknowledgement iv
Table of Content v
List of Tables viii
List of Figures ix
List of Abbreviations xiv
1. INTRODUCTION 1
1.1 Introduction 1
1.2 Background of Problem 2
1.3 Problem Statement 3
1.4 Objectives 3
1.5 Overview of the Dissertations 3
1.6 Activity Planning 5
2. LITERATURE REVIEW 6
2.1 Introduction 6
2.2 Metal Inert Gas (MIG) 6
2.3 Stainless Steel 7
2.3.1 Stainless Steel composition 8
2.4 Cladding Process 10
2.4.1 Heat Source for Cladding 11
2.5 Parameter 13
2.5.1 Effect of process parameter on dilution 14
2.6 Dilution 15
2.7 Microstructure 16
2.7.1 Solidification Mode 16
2.8 Hardness 17
vi
2.9 Summary 19
3. EXPERIMENTAL METHODS 20
3.1 Introduction 20
3.2 Design of Jig 22
3.3 Research Flow 24
3.4 Material 24
3.4.1 Mild Steel 25
3.5 Direct Deposition Process 25
3.5.1 Equipment Set Up 25
3.5.2 Deposition Parameter 27
3.5.3 Cladding Process 28
3.6 Microscopical Technique 29
3.7 Rockwell Hardness Testing 30
3.8 Statistical Analysis (Response Surface Methodology) 32
3.8.1 Variable Machining Parameter 32
3.8.2 Response Variable 32
3.8.3 Design of Experiment Matrix 33
4. EFFECT OF PARAMETERS ON HARDNESS 34
4.1 Introduction 34
4.2 Design of Experiment 34
4.2.1 Design Factor 35
4.2.2 Design Summary 36
4.2.3 Relationship between Independent and Response Variable 37
4.2.4 Variables Criteria 40
4.2.5 Optimization of Variables 42
4.3 Summary 44
5. MACROSTRUCTURE, MICROSTRUCTURAL DEVELOPMENT
AND HARDNESS VARIATIONS OF CLADDINGS 45
5.1 Introduction 45
5.2 Microstructure Characterization 45
vii
5.2.1 Base metal Microstructure 46
5.3 Macrostructure of One Stainless Steel Clad 47
5.4 Microstructure Development of Stainless Steel Clad 48
5.4.1 Fusion Zone 50
5.4.2 Heat Affected Zone 51
5.5 Hardness Variation 52
5.6 Hardness Variation at Cladding Layer 53
6. DISCUSSIONS 54
6.1 Introduction 54
6.2 Effect of Current on Hardness 54
6.3 Effect of Voltage on Hardness 55
6.4 Effect of Travel Speed on Hardness 56
6.5 Optimization of Parameter Model versus Experimental 56
6.6 Establish Cladding Process 56
7. CONCLUSION AND FUTURE WORKS 57
7.1 Introduction 57
7.2 Summary of Research 57
7.3 Research Findings 58
7.4 Future Work Recommendation 58
7.5 Conclusion 59
REFERENCES 60
APPENDICES 62
A Appendix A 63
B Appendix B 68
C Appendix C 71
D Appendix D 75
E Appendix E 79
viii
LIST OF TABLES
2.1 Chemical composition of the 304L stainless steel in wt% 8
2.2 Mechanical Properties of the 304L stainless steel in wt% 9
2.3 Properties of Clad Layer 11
2.4 Process parameter varied at five levels 13
2.5 Solidification types and microstructure 17
3.1 Nominal composition of stainless steel wire (ER308L) 25
3.2 The cladding conditions for plate thickness 5mm 27
3.3 Parameter and its limit 32
3.4 Design of Experiment Matrix 33
4.1 Design factor 35
5.1 Solidification type, reactions, and resultant microstructure 48
5.2 Hardness variation at cladding layer of stainless steel 51
ix
LIST OF FIGURES
1.1 High Power Diode Laser (HPDL) System 2
2.1 Metal Inert Gas Process 6
2.2 Laser Cladding Process 10
2.3 Two stage (preplaced) and one stage (in-situ) laser cladding 11
2.4 Effect of input numeric factors in GMAW process 14
2.5 Cross section of a single clad layer with definition of the clad geometry 16
2.6 Rockwell hardness 18
3.1 The flow chart of experimental research 21
3.2 Isometric View (Jig) 22
3.3 Orthographic View (Jig) 22
3.4 Isometric View (Bar) 23
3.5 Orthographic View (Bar) 23
3.6 Filler wire used in this experimental Process 24
3.7 Gas Metal Arc Welding (GMAW) Setup for Deposition Process 26
3.8 One layer clad 28
3.9 Seven layers clad by overlapping ¼ of the clad width 28
3.10 Optical Microscope 29
3.11 Grinder machine 29
3.12 Polisher machine 30
3.13 Rockwell hardness test diagram 31
3.14 Comparison between common hardness scales 31
4.1 Design Summary 36
4.2 Relationship between current and hardness 37
4.3 Relationship between voltage and hardness 38
4.4 Relationship between travel speed and hardness 39
4.5 Variable criteria for current 40
x
4.6 Variable criteria for voltage 40
4.7 Variable criteria for travel speed 41
4.8 Variable criteria for hardness 41
4.9 Constraints and Solution for DOE 42
4.10 Relationship between optimal parameters and hardness 43
5.1 Macrostructure of low-carbon steel 0.1%-0.3% 44
5.2 Ferrite and Pearlite grain in Mild Steel Microstructure
at 20x magnification 44
5.3 130A (current), 24 inch per minute (travel speed) and 22V (arc voltage) 45
5.4 A) Current at 153A B) current at 130A 45
5.5 A) Travel speed at 32ipm B) travel speed at 27ipm 46
5.6 Cladding area and HAZ microstructure for optimal set of parameters 47
5.7 The fusion zone type FA that occurs at cladding
stainless steel (50X magnification) 48
5.8 Relationship of solidification type to the pseudobinary phase diagram 49
5.9 Ferrite along the austenitic grain boundaries in the HAZ 49
5.10 Hardness variation at different spot of cladding stainless steel 50
6.1 A) Current at 190A B) current at 115A 55
6.2 A) Result of calculation of the SDAS 55
6.3 Seven layers clad 56
xiv
LIST OF ABBREVIATIONS
CAD - Computer-Aided Design
CRES - Corrosion-Resistant Steel
DMD - Direct Metal Deposition
GMA - Gas Metal Arc
GMAW - Gas Metal Arc Welding
GTA - Gas Tungsten Arc
GTAW - Gas Tungsten Arc Welding
HAZ - Heat Affected Zone
LENS - Laser Engineered Net Shaping
MIG - Metal Inert Gas
RSM - Response Surface Methodology
SEM - Scanning Surface Microscopy
TIG - Tungsten Inert Gas
AISI - American Iron Standard Institute
AWS - American Welding Society
ASTM - American Society for Testing and Materials
DOE - Design of experiment
1
CHAPTER 1 INTRODUCTION
1.1 Introduction
Cladding is a well established process used in a variety of industries for improving
the surface and near surface properties (wear, corrosion or heat resistance) of a part,
or to resurface a component that has become worn through use. Cladding typically
involves the creation of a new surface layer having different composition than the
base material, as opposed to hardening which simply entails changing the properties
of the substrate itself in a thin surface layer. There are currently quite a number of
different techniques for performing cladding each with its own specific
characteristics in terms of the materials employed, the quality of the clad layer and
various practical issues including throughput speed, process compatibility, and cost.
Laser based processes are amongst these techniques however, their implementation
has been limited to both cost and various implementation factors.
Over the past several years, a new type of cladding tool based on high power diode
lasers has become available. In many instances, this technology offers superior
overall clad quality, reduced heat input, minimal part distortion and better clad
deposition control than traditional technology, while also delivering lower operating
cost and easier implementation than other laser based methods. Figure 1.1 shows a
schematic of the High Power Diode Laser system.
2
Figure 1.1: High Power Diode Laser System (Neill Boyle, Aidan Kennedy & John Connolly (1999)).
1.2 Background of Problem
To improve the surface properties of metallic mechanical parts, such as the resistance
against wear and corrosion, several thermal surface treatments are available for
instance are flame spraying, plasma spraying and arc welding are established
techniques. Characteristic for these techniques is the application of a surface layer
with the required properties on top of a cheap material without those properties.
Depending on the applied technique, common problems are a combination of a poor
bonding of the applied surface layer to the base material, the occurrence of porosity,
the thermal distortion of the work piece, the mixing of the surface layer with the base
material and the inability of a very local treatment.
The techniques that overcome these problems are laser cladding. Laser cladding has
been defined as “a process which is used to fuse with a laser beam another material
which has different metallurgical properties on a substrate, whereby only a very thin
layer of the substrate has to be melted in order to achieve metallurgical bonding with
minimal dilution of added material and substrate in order to maintain the original
properties of the coating material” (Komvopoulos, 1990).
3
1.3 Problem Statement
Based on this study, several main points need to be focused and questions need to be
answered at the end of the topic:
i. How different deposition parameters affected macrostructure and
microstructure of stainless steel deposited material?
ii. How different deposition parameters affected hardness of stainless steel
deposited material?
1.4 Objectives
Objectives of this study are as follows:
i. To investigate how different deposition parameters affected macrostructure
and microstructure of stainless steel deposited material.
ii. To investigate how different deposition parameters affected hardness of
stainless steel deposited material.
iii. To establish whether stainless steel can be deposited as cladding using MIG
as heat source.
1.5 Overview of the Dissertations
Chapter 1 provide fundamental of cladding process and its applications. In addition,
background of this research also reviewed in this chapter. Problem statement and
objectives of this experimental research are stated based on the task given.
Chapter 2 presents a review of the literature about the effect of (MIG) process
condition on dilution of stainless steel claddings of a carbon steel substrate. Beside,
the literature about Metal Inert Gas (MIG) heat source and process also review in this
chapter. Background knowledge about stainless steel material is also provided in
4
relation to its process parameter, dilution, and macrostructure and hardness variation.
Summary of literature review is provided at the end of this chapter.
Chapter 3 describes an experimental method of this research including design of
experiment, experimental flow, equipment set up and technique used. Introduction on
some method and approach in selecting an optimize parameters for this experimental
research also stated in this report. This chapter provides statistical analysis of direct
metal deposition. The conclusion of this chapter would interpret as research flow
along this research.
Chapter 4 describes the result of the design of experiment. Interpretation on some
result and finding of this research also stated in this chapter. This chapter provides
statistical analysis of the design of experiment. The main parameters of the process
are current, voltage and travel speed. These parameters are not independent.
Chapter 5 describes a macrostructure, microstructure development and hardness
variations of as-deposited stainless steel using wire feed method. Introduction on
some method and approach in determining macrostructure, microstructure
development and hardness variations of as-deposited also stated in this report. This
chapter provides interpretation of experiment result and its discussion.
Chapter 6 describes a conclusion of this research including interpretation of overall
research flow. The overall research objectives, scope, findings and discussions also
conclude in this chapter. Finally, this chapter provides recommendation of future
works.
5
1.6 Activity Planning
The used of Gantt chart is an effective tool for planning and scheduling operations
involving a minimum of dependencies and interrelationships in this experimental
research. On the other hand, the charts are easy to construct and understand, even
though they may contain a great amount of information. In general, the charts are
easily maintained provided the task requirements are somewhat static. Updating of a
Gantt chart will reveal difficulties encountered in the conduct of this experimental
project. Gantt chart of this experimental research is provided in Appendix A.
6
CHAPTER 2 LITERATURE REVIEW
2.1 Introduction
This chapter presents a review of the literature about the effect of (MIG) process
condition on dilution of stainless steel claddings of a carbon steel substrate. Beside,
the literature about metal inert gas (MIG) heat source and process also review in this
chapter. Background knowledge about stainless steel material is also provided in
relation to its process parameter, macrostructure properties, microstructure properties
and hardness variation. Summary of literature review is provided at the end of this
chapter.
2.2 Metal Inert Gas (MIG)
MIG welding or GMAW is a process that melts and joints metals by joint metal by
heating them with an arc established between a continuously fed filler wire electrode
and the metals as shown in figure 2.1.
Figure 2.1: Metal Inert Gas Process (O’Brien, RL (1997)).
7
Shielding of the arc and the molten weld pool is often obtained by using inert gases
such as argon or helium. This process applied a continuous and consumable wire
electrode. Carbon dioxide or argon-oxygen mixtures are suitable for arc shielding
when welding the low-carbon and low-alloy steels, while pure inert gas may be
essential when welding highly alloyed steels (Kou, 2003).
Pure inert gas shielding is essential for welding alloys of aluminum, magnesium,
copper, titanium, zirconium, stainless steels and nickel base super alloys. MIG
welding is normally perform with direct current electrode positive because it
provides a stable arc, smooth metal transfer, relatively low spatter loss and good
weld characteristics. The gas metal arc process or metal inert gas process can be used
for spot welding to replace either riveting, electrical resistance or GTA (TIG) spot
welding (Lincoln Arc Welding 2001).
Originally developed for welding aluminum and other non-ferrous materials in the
1940s, MIG was soon applied to steels because it allowed for lower welding time
compared to other welding processes. The cost of inert gas limited its use in steels
until several years later, when the use of semi-inert gases such as carbon dioxide
became common (Lincoln Arc Welding Foundation, 2001).
Advantages of using MIG welding according to Lincoln Arc Welding Foundation,
(2001) are as follows:
a) Very clean due to the application of inert shielding gas
b) Higher deposition rate, thicker work pieces can be welded at higher speed
c) Can master the welding skill in short time
2.3 Stainless Steel
In metallurgy, stainless steel, also known as inox steel or inox, is defined as a steel
alloy with a minimum of 11% chromium content by mass. Stainless steel does not
stain, corrode, or rust as easily as ordinary steel (it stains less, but it is not stain-
proof). It is also called corrosion-resistant steel or CRES when the alloy type and
8
grade are not detailed, particularly in the aviation industry. There are different grades
and surface finishes of stainless steel to suit the environment to which the material
will be subjected in its lifetime. Common uses of stainless steel are cutlery and watch
cases and bands.
Stainless steel differs from carbon steel by the amount of chromium present. Carbon
steel rusts when exposed to air and moisture. This iron oxide film (the rust) is active
and accelerates corrosion by forming more iron oxide. Stainless steels have sufficient
amounts of chromium present so that a passive film of chromium oxide forms which
prevents further surface corrosion and blocks corrosion from spreading into the
metal's internal structure.
2.3.1 Stainless steel composition
Stainless steel AISI 304 and 304L has a composition as shown below (Table 2.1)
(Balbaud, 2007).
Table 2.1: Chemical composition of the 304L stainless steel in wt% (Balbaud, 2007).
Type 304 %
Type 304L %
Carbon 0.08 max. 0.03 max.
Manganese 2.00 max. 2.00 max.
Phosphorus 0.045 max. 0.045 max. Sulfur 0.030 max. 0.030 max.
Silicon 0.75 max. 0.75 max.
Chromium 18.00-20.00 18.0-20.0
Nickel 8.00-12.00 8.0-12.0 Nitrogen 0.10 max. 0.10 max.
Iron Balance Balance
9
Table 2.2: Mechanical Properties of the 304L stainless steel in wt% (Balbaud, 2007).
UTS
Ksi (MPa)
0.2% YS
Ksi (MPa)
Elongation
% in 2”
(50.8 mm)
Hardness
Rockwell
Type 304L 85 (586) 35 (241) 55 B80
Type 304 90 (621) 42 (290) 55 B82
Stainless steel AISI 304L has a wide variety of applications in a condition where the
following properties are important:
a) Resistance to corrosion
These steels exhibit excellent resistance to a wide range of atmospheric,
chemical, textile, and petroleum and food industry exposures.
b) Resistance to oxidation
The maximum temperature can be exposed continuously without
appreciable scaling is about 1650°F (899°C). For intermittent exposure,
the maximum exposure temperature is about 1500°F (816°C).
c) Ease of fabrication
d) Excellent formability
e) Ease of cleaning
f) High strength with low weight
g) Good strength and toughness at cryogenic temperatures
h) Readily available of a wide product forms
Lee, (2006) specified that for AISI 304L stainless steel, because of the advantages
it has in mechanical and anti-corrosion properties, the area of its application has
been widely engaged in chemical, automotive and nuclear industries. In practical,
AISI 304L stainless steel weldments are often required to operate in a
dynamic mode, and consequently they are frequently subjected to impact
forces. Therefore, these components require a design that has to be fully
understood of the impact response and fractured characteristics of the 304L stainless
steel weldments.