UNIVERSITI TEKNIKAL MALAYSIA MELAKA
BORANG PENGESAHAN STATUS LAPORAN PROJEK SARJANA MUDA
TAJUK: Mechanical properties determination of mild steel and stainless steel
joint fabricated by MIG welding process
SESI PENGAJIAN: 2009/10 Semester 2
Saya SHAHRIR BIN SAHARI
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
(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)
TIDAK TERHAD
Disahkan oleh:
Alamat Tetap:
Cop Rasmi:
Lot 156 Kg Baru Peramu,
26060 Kuantan,
Pahang Darul Makmur.
Tarikh: _________________________
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.
DECLARATION
I hereby, declared this report entitled “Mechanical properties determination of mild steel
and stainless steel joint fabricated by MIG welding process
” is the results of my own research except as cited in references
Signature
:
Author’s Name
:
…………………………………………….
SHAHRIR BIN SAHARI
…………………………………………….
Date
:
…………………………………………….
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) with Honours. The member of the supervisory
committee is as follow:
(Signature of Supervisor)
……..………………………………
(Official Stamp of Supervisor)
ABSTRAK
Tujuan projek ini adalah untuk menentukan prilaku mekanik dan daerah terkesan haba
(HAZ) pada struktur mikro, terhadap kimpalan diantara besi baja yang mengandungi
peratusan yang karbon rendah dan keluli tahan karat dengan menggunakan proses
kimpalan keluli gas arka (MIG). Keluli tahan karat daripada kelas (AISI 304) dah besi
baja karbon rendah (AISI 1010) telah digunakan dalam projek ini. Kedua-duanya yang
berketeblan 4 mm telah dikimpal bersama logam penambah (AWS ER309) yang berbeza
diameter iaitu (0.8 mm dan 1.2 mm). Mesin kimpal (WIM 210S) telah digunakan untuk
tujuan tersebut, yang mana parameter terkawal adalah voltan, kelajuan suap logam
penambah dan kadar alir gas pelindung. Ujian – ujian mekanik yang dilaksanakan adalah
ujian kekuatan tarikan, ujian keteguhan hentaman, dan ujian kekerasan. Di penghujung
analisa didapati terdapat perubahan nilai kekerasan pada setiap bahagian seperti besi
asas, kawasan terkesan haba dah bahagian kimpalan itu sendiri. Kekerasan yang tinggi
telah dicatat pada kawasan terkesan haba di kedua- dua belah sambungan. Ujian terikan
pula menunjukkan kimpalan menggunakan logam penambah berdiameter 0.8 mm adalah
lebih tegar daripada 1.2 mm. Sungguhpun begitu, kesemua bahan ujian telah gagal pada
kawasan terkesan haba di sebelah (AISI 1010) yang berkemungkinan disebabkan oleh
kurangnya pelakuran antara logam penambah dan besi baja karbon rendah.
Walaubagaimanapun, ujian struktur micro menunjukkan adanya keretakan berlaku pada
bahagian HAZ tersebut yang menyumbang pada kegagalan semasa ujian keterikan.
Akhir sekali, tumpuan haruslah diberikan sepenuhnya terhadap rekabentuk, procedur,
spesifikasi dan teknik mengimpal besi yang berlainan jenis untuk mendapat keputusan
yang baik sebelum berjaya menentukan penetapan perilaku mekanik terhadap sesuatu
sambungan kimpalan.
ii
ABSTRACT
The purpose of this study is to determine the mechanical properties and the
microstructure behavior at weldment and HAZ of mild steel and stainless steel joint
fabricated using MIG welding process. Material from grade Austenitic stainless steel
(AISI 304) and mild steel (AISI 1010) with both thickness 4 mm were used. Welding
design was done in single groove butt joint and weld using 1.2 mm and 0.8 mm diameter
size of filler wire (ER309). Welding machine (WIM 210S) was used with selected
parameter with involved voltage, wire feed speed and gas flow rate. Mechanical
properties were evaluated in tensile tests, Charpy-V toughness tests, and hardness test. In
addition microstructure examinations were carried out. Base on the finding, there was
changes in hardness value on base metal, weldment and HAZ area. High hardness value
has been identified at both HAZ area of dissimilar weld. Tensile test show at 1.2 mm
strength was weaker than 0.8 mm joint. All specimens were fracture at HAZ near AISI
1010 side because of lack of fusion. At their barrier microstructures reveal that present
of crack at HAZ near AISI 1010 and show little dilution in intermetallic of dissimilar
metal. No ferrite structure present because MIG welding provide rapid cooling. All the
implication in the dissimilar weld disturbance and affect the whole properties.
i
ACKNOWLEDGEMENTS
First and foremost, I would like to thank Almighty Allah for allowing me to successfully
complete this report. I also would like to convey my thanks to the all person who had
contributed in ensuring a successful occurrence throughout the duration of my final year
project. I also would like to take this opportunity to express my gratitude to Mr. Mohd
Shukor bin Salleh as my supervisor for his guidance and support. I also want to express
my whole-hearted thanks to all my friends who are also my comrades in times of need.
Last but not list those mentioned, I would like to express my gratitude with highly
appreciation and dedication to my family with their support morally in completing my
final year project and motivate to success and complete study in Universiti Teknikal
Malaysia, Melaka (UTeM).
iv
TABLE OF CONTENTS
Abstract
i
Abstrak
ii
Dedication
iii
Acknowledgement
iv
Table of Contents
v
List of Figures
ix
List of Tables
xii
List of Abbreviations
xiii
CHAPTER 1: INTRODUCTION
1.1
Introduction
1
1.2
Project Background
3
1.3
Problem Statement
4
1.4
Objective
6
1.5
Scope of Project
6
1.6
Report Organization
7
1.7
Project Planning
7
CHAPTER 2: LITERATURE REVIEW
2.0
Introduction
8
2.1
Stainless Steel
10
2.1.1
Typical Stainless Steel Application
10
2.1.2
Austenitic (200 and 300 series)
11
2.2
2.3
Low Carbon Steel (Mild Steel)
12
2.2.1
12
Typical Mild Steel Application
Gas Metal Arc Welding (GMAW)
13
v
2.3.1
2.4
MIG Metal Transfer
14
2.3.1.1 Spray Transfer
14
2.3.1.2 Globular Transfer
15
2.3.1.3 Short Circuiting Transfer
15
2.3.2
MIG Equipment Setup
16
2.3.3
Principles of Operation
17
Dissimilar Metal Welding
18
2.4.1
Weld Metal
18
2.4.2
Dilution
19
2.4.3
Melting Temperature
19
2.4.4
Thermal Conductivity
19
2.4.5
Coefficient of Thermal Expansion
19
2.5
Welding Stainless Steel and Mild Steel
20
2.6
Welding Consideration
20
2.6.1
Filler Wire Selection for Dissimilar Metal
20
2.6.2
Buttering Process
22
2.6.3
Joint Design for MIG
23
2.6.4
Butt Joint
23
2.6.5
Shielding Gas
24
2.7
Variation for MIG welding Process
25
2.8
Mechanical Properties
25
2.8.1 Tensile Test
26
2.8.2 Stress –Strain Curves
26
2.8.3 Basic Calculation
27
2.8.4 Ductility
28
Hardness Test
28
2.9.1
29
2.9
2.10
Rockwell hardness test
Impact Test
29
2.10.1 Toughness
30
2.11
Weldment Microstructure
30
2.12
Heat Affected Zone
32
vi
CHAPTER 3: METHODOLOGY
3.0
Introduction
34
3.1
Process Flow Chart
35
3.2
Materials preparation
36
3.2.1
36
Raw Material
3.3
Equipment preparation
37
3.4
Design of Experiment (D.O.E)
38
3.4.1
Determine MIG welding Settings
38
3.4.2
Procedure of Hardness Measure
39
3.5
3.6
3.7
3.8
Machine Setup
40
3.5.1
Install Filler wire
40
3.5.2
Contact Tip Change
41
Welding Experiment
41
3.6.1
Cutting the Material
41
3.6.2
Joint Design Process
42
3.6.3
Buttering Process
42
3.6.4
Tack Weld process
43
3.6.5
Welding process
43
Specimen Preparation
44
3.7. 1 Cutting process
45
3.7.2
Tensile Specimen (ASTM E8)
45
3.7.3
Hardness Specimen (ASTM 10)
46
3.7.4
Microstructure Specimen (ASTM E3)
47
3.7.5
Impact Specimen (ASTM E23)
48
Experimentation
48
3.8.1
Hardness Test Measurement
49
3.8.2
Tensile Test Measurement
49
3.8.3
Impact Test Measurement
50
3.8.4
Microstructure Analysis
51
vii
CHAPTER 4: RESULT AND DISCUSSION
4.1
Hardness Result-D.O.E
53
4.2
Actual Experiment
56
4.3
Hardness Result
56
4.3.1
57
4.4
Hardness Data Analysis
Results for Tensile Test
59
4.4.1
Data Collected Analysis
60
4.4.2
Stress versus Strain Analysis
61
4.5
Results for Charpy Impact
63
4.6
Results for Microstructure Analysis
64
4.6.1
Sample A -Filler wire 1.2 mm with 20X Magnifier
64
4.6.2
Sample F- Filler wire 0.8 mm with 20X Magnifier
65
4.7
Relation of the Results
67
CHAPTER 5: CONCLUSION AND RECOMMENDATION
5.0
Introduction
68
5.1
Result overview
68
5.2
Conclusion
69
5.3
Recommendation
70
REFERENCES
71
APPENDICES
A
Gantt chat
B
Hardness test result
B
Tensile test result
D
Microstructure Analysis
viii
LIST OF FIGURES
1.0
Dissimilar metal joint in Volvo S40
3
2.1
Basic principle of MIG welding
13
2.2
Spray transfer
14
2.3
Globular transfer.
15
2.4
Short-circuiting transfer.
16
2.5
Schematic of equipment setup for MIG
16
2.6
Illustration operation of MIG
17
2.7
Effect of electrode position and welding technique.
17
2.8
A Schaeffler diagram and the procedure of estimating the
21
microstructure of E309-type.
2.9
Buttering process used to assist in dissimilar welding
22
2.10
Bevel angle, groove angle, and root opening of joints for welding.
23
2.11
Shielding gas related to weld profile for DCEP
24
2.12
Diagram of tensile test machine
26
2.13
Typical stress-strain curve obtained from tensile test.
27
2.14
Rockwell hardness testing technique.
29
2.15
Charpy-V notch impact apparatus.
30
2.16
Optical microstructure of parent metal Austenite 304 stainless steel.
31
2.17
Optical microstructure of parent metal plain mild steel.
31
2.18
Heat affected zone microstructure Austenitic steel side.
31
2.19
Anatomy of a weld.
32
3.1
Process Flow Chart
35
3.2
Stainless steel plate
36
3.3
Mild Steel Plate
36
3.4
Filler Wire specification
37
3.5
MIG Machine Specification
37
ix
3.6
Hardness measured point for D.O.E purpose
39
3.7
Hardness test in progress
39
3.8
Show the sequence to install the filler wire
40
3.9
Procedure to change the MIG contact tip
41
3.10
Beveling process.
42
3.11
Buttering process at AISI 1010 side
42
3.12
Allocated the tack weld.
43
3.13
MIG welding in action
43
3.14
Finish welded part with 45 degree single groove butt join type
44
3.15
The way specimen cut from weld part
44
3.16
Cutting the specimen for testing
45
3.17
Standard specimen for tensile test
45
3.18
Tensile specimen for 1.2 mm diameter filler wire
46
3.19
Example of hardness test specimen
46
3.20
Hardness test specimens
47
3.21
Metallographic specimens.
47
3.22
Specimen for charpy impact test
48
3.23
Rockwell hardness machine
49
3.24
Hardness test process
49
3.25
Tensile machine in progress
50
3.26
Impact Tester
51
3.27
Specimen with before and after impact test
51
3.28
Image Analyzer (Buehler Omniment).
52
3.29
Grinding and polishing equipment (Buehler).
52
4.1
Hardness Result for 1.2 mm filler wire
53
4.2
Hardness Result for 0.8 mm filler wire
54
4.3
Hardness measure point
54
4.4
Mean of hardness value on dissimilar metal joint.
57
4.5
Tension test specimen
59
x
4.6
Properties comparison between different size filler wire.
60
4.7
Result tension test for specimen A
61
4.8
Result tension test for specimen F
62
4.9
Show the Result obtain from Charpy test
63
4.10
Physical appearance of the specimen after the test
63
4.11
Metallographic observation on 1.2 mm (20 X)
64
4.12
Metallographic observation on 0.8 mm (20 X)
65
4.13
Heat Affected zone (HAZ) and weldment
66
4.14
Solidification Crack was identifying using both filler wire.
67
xi
LIST OF TABLES
2.1
Minimum Mechanical Properties for annealed Alloys
11
2.2
Nominal Compositions of Austenitic Stainless Steels.
11
2.3
Mechanical properties of selected carbon steel.
12
2.4
Composition of selected carbon steel.
12
2.5
The nominal chemical compositions of the alloy steel
21
2.6
Mechanical properties of ER309
21
2.7
Recommended parameter for MIG using welding grade CO2
22
2.8
The variation of the MIG welding process.
25
2.9
Recommended etching solution for dissimilar metal
32
3.1
General setting parameter for MIG welding process
38
3.2
Best Parameter for Welding machine MIG 210S
40
3.3
Standard specimen size for tensile experiment (From ASTM E8)
46
3.4
Parameter for Hardness test machine
49
3.5
Parameter for tensile test machine
50
4.1
MIG parameter for 1.2 mm filler wire
55
4.2
MIG parameter for 0.8 mm filler wire
55
4.3
Specimen number for each filler wire
56
4.4
Convert HRB value to approximate tensile strength
58
4.5
Data of tensile test using 1.2 mm and 0.8 mm MIG filler wire
60
5.1
Mechanical properties
69
xii
LIST OF ABBREVIATIONS
AWS
-
American Welding Society
AISI
-
American Iron and Steel Institute
ASTM
-
American Standard Testing for Material
ASME
-
American Society of Mechanical Engineer
BHN
-
Brinell Hardness Number
Cr
-
Chromium
CV
-
Constant Voltage
CO2
-
Carbon dioxide
DCEP
-
Direct Current Electrode positive
DCEN
-
Direct Current Electrode Negative
GTAW
-
Gas Tungsten Arc Welding
GMAW
-
Gas Metal Arc Welding
HAZ
-
Heat Affected Zone
MIG
-
Metal Inert Gas
Mn
-
Manganese
Ni
-
Nickel
PSM
-
Projek Sarjana Muda
SMAW
-
Shield Metal Arc Welding
SAW
-
Submerge Arc Welding
UTeM
-
Universiti Teknikal Malaysia Melaka
xiii
CHAPTER 1
INTRODUCTION
1.1
Introduction
Welding is very common technique in order to join two or more types of metal. Welding
is used to join all commercial metals and alloys and to joint metal of different type of
strength. Welding begin as a repair or maintenance tool and has become one of the most
crucial manufacturing methods as well as the most essential construction method.
Almost everything made of metal is welded. Because of its strength and versatility,
welding is used in manufacture of almost all the products used in our life every day.
Without welding many community cannot afford the cost of the goods and services they
need to earn a living (Cary & Helzer, 2005).
American welding society (AWS) has defined welding as “a joining process that
produce coalescence of materials by heating them to the welding temperature, with or
without the application of pressure or by the application of pressure alone, and with or
without the use of filler metal”. Welding goes well beyond the bounds of its simple
description. Welding today is applied to a wide variety of materials and products, using
such advanced technologies such as lasers and plasma arcs. The future of welding holds
even greater promise as methods are devised for joining dissimilar and non-metallic
materials, and for creating products of innovative shapes and designs.
1
For an example, the famous trans-Alaska pipeline, a super-tanker, the world largest
moving weldment, storage tank for water supply systems, the sears Tower in Chicago
would not be possible without welding. The international space station was welded
together on earth and transported to space, and the final assembly welds were done in
space. The shuttle itself, from the rocket engines to the external fuel tank, required
specialized procedures for welding alloy aluminum without defects. Most large airplanes
include much welding, even miniature components for electronic equipment and
telecommunication equipment. All of these prove that welding is important in many
applications (Cary & Helzer, 2005).
There are many types of welding processes and also many ways to make a weld. Some
welding processes do not cause spark, use electricity, or required heat. Many different
energy sources can be used for welding, including a gas flame, an electric arc, a laser, an
electron beam, friction, and ultrasound. While often an industrial process, welding can
be done in many different environments, including open air, under water and in outer
space (Cary & Helzer, 2005).
2
1.2
Project Background
Welded dissimilar metal joints become widely accepted as the superior design option for
manufactured products between their quality, reliability, and serviceability. The welding
industries are working to remove reservations in areas where there is concern about
welded joints due to limitations of materials, process, and ability to ensure quality. In the
recent years, welding dissimilar metal joint promotes various service conditions such as
resistance to corrosion, heat resistance and magnetic properties. A lot of study has been
done with the dissimilar welding technology nowadays.
Wagner et al. (2000) shows there were a lot of wide variety of possible applications for
dissimilar material combinations. At present, the main focus in this area is aiming car
body concepts for weight reduction and higher stiffness due to the locally use of
aluminum sheet materials. For power train components the combination of aluminum
parts with thin walled steel pipes offers the opportunity for a significant reduction of the
rotating masses. Under this concern, higher product efficiency could be realized.
Figure 1.0: Dissimilar metal joint in Volvo S40 (Available at: http://www.designnews.com).
Realizing the important of welding dissimilar metal nowadays; the research about
joining the material of mild steel and stainless steel fabricated by using MIG welding
process has been carrying out. In contrast, this research is subjected to determine the
mechanical properties of dissimilar metal joint and also to study the characteristic of the
weldment area. This is important to understand behavior of dissimilar joint at the basic
point of view before applying them to the real application.
3
1.3
Problem Statement
Weld between dissimilar metals relates to the transition zone between the metal and the
intermetallic compounds formed in this transition zone. For the fusion welding
processes, it is important to investigate the composition of two metals involved. If there
is mutual solubility of the two metals, the dissimilar joint can be made successfully. If
there is little or no solubility between the two metals to be joined, the weld joint will not
be successful (Cary & Helzer, 2005).
Al Wadleigh (1991) derive dissimilar metals have different chemistries, so they have
different physical properties such as melting temperature. Many who have involved with
joining metal with different melt temperature experience frustration. The difficulties was
arise when someone try to melt metal together at same weld temperature. For example
mild steel and stainless steel, obviously in nature these materials have different melting
point.
MIG welding is widely used in many industry applications such as automotive, oil and
gas, agriculture, and construction. Their versatility, rapid, economical, capable in all
weld position, technique, speed and high deposition is the reason why it most used. MIG
welding can operate with semiautomatic or automatic and work with most metal
(Kalpakjian & Schmid, 2006).
MIG welding does not require particular skill level and it is capable to be carried out by
fresh welder with some basic instruction. Hence, it is provided with semiautomatic mode
which is appropriate to reduce the human factor error that contributes to weld quality as
well as to acquire the better result. In weld a dissimilar metal, MIG welding is twice
better than SMAW in term of productivity from deposition of the welt metal on the base
metal, and good consumable utilization (Cary & Helzer, 2005).
4
Kiling (2001) stated that scope of application of MIG welding in German is over 75%
nowadays, it is being used in partial mechanized, fully mechanized and automate
technique. MIG welding produce high quality weld at high speed without the used flux
and limited postweld cleaning. It is very desirable for both small and high production
metal joining. It frequently replaces other joining process such as riveting, brazing,
silver-soldering, or resistance welding. MIG welding is better than friction welding in
term of flexibility because friction welding constraint for round billet shape or pipe only.
It may be used instead of the following fusion welding process; submerge arc welding,
flux core and gas tungsten arc welding.
However material such Mild steel and stainless steel are widely used in many
applications such as construction, power plant, petrochemical, offshore, and more. Mild
steel is low carbon steel that easy to form and has excellent weldability meanwhile
stainless steel has popular as resistant to corrosion material and weldable with various
application (Kalpakjian & Schmid, 2006).
Realizing the important on joining dissimilar metal and its application in many industry
nowadays it is essential to joining various of metal in order to reducing cost and meet
the specification of the product. Engineer is essential to study the properties of the weld
join in order to design and size the load carrying for economic and safety concern.
Hence, the study on the mechanical properties determination of mild steel and stainless
steel joint fabricated by MIG welding process was necessary to provide understanding of
dissimilar weldments from the basic point of view.
5
1.4
Objective
The objectives of the research are as follow:
a)
To study the effect on mild steel and stainless steel joint using different
diameter filler wire of MIG welding.
b)
To evaluate weld properties through the Hardness, Tensile, and
Microstructure.
c)
To analyze the characteristic of weldment and heat affected zone (HAZ)
microstructure.
1.5
Scope of Project
Here, scope act as the guidance that permits this research is doing without loss the
focusing. It is capable to bring the project to their objective without run out by doing
work that not relate to the objective. Welding process has done using MIG welding
machine (WIM 210S). Three controlled parameter such Voltage, Wire feed and Gas
flow rate was selected which respect to the welding standard and machine capability.
Material used is from type (AISI 1010) mild steel and (AISI 304) stainless steel with
both thickness 4 mm. the joint design was single groove butt joint with flat position (1G)
by different diameter of MIG welding filler wire (ER309) which is 1.2 mm and 0.8 mm.
Specimen was prepared according to AWS and ASTM respectively to study the
mechanical properties such state in the objective. Other variables are not mention here
become a limitation of this project scope.
6
1.6
Report Organization
Chapter 1: Introduction
a) This chapter briefly explained the background of the project study, the objective
that want to achieved, the problem statement and finally whole project planning
through Gantt chart.
Chapter 2: Literature Review
a) This chapter was collection of research information that relate to the study from
any trusted resources.
Chapter 3: Research Methodology
a) This chapter explains the structure on how project was done
Chapter 4: Result and Discussion
a) The output from the study was precisely explain and discussed in this chapter.
Chapter 5: Conclusion and Recommendation
a) This chapter finally explains the achievement of whole project to compare with
objectives.
1.7
Project Planning
The purpose of the project planning was to meet the due date. Besides that, it was very
important tool to manage the project smoothly and flexible. Although, Gantt chat was
developed for that purpose, it shows the time line for every task and targeted plan. From
Gantt chart the entire process was clearly preview, and the way to start the project was
easy to understand. Hence, Gantt chart was attached at Appendix A.
7