INVESTIGATION ON THE DIFFERENT TYPES OF MATERIALS OF JOINING FOR AUTOMOTIVE PANEL MOHAMAD SUHAIMI BIN SAMSUD1N A report in partial fulfillment of the requirements for the award of the degree of Bachelor of Mechanical Enginçering with Manufacturing Engineering Faculty of Mechanical Engineering Universiti Malaysia Pahang NOVEMBER 2007 (.,. PRPST&i(AN NtVER 4 flt. , IALAV S1A PAHANG oehafl No. Png9n 030497 Taikh - 30 MAY 2t1U '5
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INVESTIGATION ON THE DIFFERENT TYPES OF MATERIALS OF JOINING
FOR AUTOMOTIVE PANEL
MOHAMAD SUHAIMI BIN SAMSUD1N
A report in partial fulfillment of the
requirements for the award of the degree of
Bachelor of Mechanical Enginçering with Manufacturing Engineering
Faculty of Mechanical Engineering
Universiti Malaysia Pahang
NOVEMBER 2007
(.,.
PRPST&i(AN NtVER 4 flt.,IALAV S1A PAHANG
oehafl No. Png9n
030497
Taikh -
30
MAY 2t1U
'5
ABSTRACT
The technique of joining two or more different panels is called as Tailor
Welded Blank (TWB). The panels could vary in thicknesses, grades or coating and
joined by the mean of welding. This technique is widely being used by automotive
manufacturer in the world because of the abundant benefits. But, Malaysian
automotive manufacturers are still lack of this advancement. Hence, this project
endeavors to build a platform for the industries by pioneering researches in this area.
So, the purpose of the project is to find the best joining materials to be integrated into
TWB by comparing each specimen and then proposed the potential TWBs to be used
as automotive panel specially aimed for door inner panel for the hinge section. Base
metals of 0.7mm thick from SPCC and SPCEN grades and 1.2 mm thick from SPHC,
SAPH 370 and SGACC grades are chosen to be the joining materials and laser
welding is chosen to be the method for joining. Each specimen will be tensile tested
in order to find the properties that influence the weldability, formability and
drawability of the TWBS. Then the data obtained will be analyze by distinguishing
them into several sets of parameter to determine the significant factor and thus,
decided the best material combination as the potential Tailor Welded Blanks.
ABSTRAK
Teknik menyambung dua atau lebih panel dipanggil sebagai Adunan
Kepingan Dikimpal atau "Tailor Welded Blank" (TWB). Panel - panel mi boleh
berbagai dari segi tebal, gred, salutan yang mana disambungkan melalui teknik
kimpalan. Teknik mi digunakan oleh hampir kesemua pengusaha automotif di dunia
disebabkan oleh kelebihannya. Tetapi, pengusaha automotif di malaysia masih
tertinggal dari segi kemajuan mi. Oleh itu, projek liii berusaha membina asas kepada
industri mi dengan memulakan penyelidikan di bidang yang dimaksudkan. Sebagai
permulaan, projek mi bertujuan untuk mencani bahan peyambungan terbaik untuk
diadaptasikan ke dalam TWB dengan membandingkan setiap spesimen seterusnya
memilih kombinasi bahan berpotensi untuk diaplikasikan kepada panel automotif
yang dikhususkan kepada panel dalaman pintu bahagian engsel. Kepingan logam dan
gred SPCC dan SPCEN berketebalan 0.7mm dan gred SPHC, SAPH 370 dan
SGACC berketebalan 1.2mm dipilih sebagai bahan peyambungan dan kimpalan laser
dipilih sebagai cam peyambungan. Setiap spesimen akan diuji untuk mencani elemen
yang mempenganuhi kebolehubahan, kebolehtanikan, dan kebolehkimpalan sesuatu
TWB. Data yang didapati akan dianalisis dengan membezakan setiap spesimen
kepada beberapa parameter untuk mementukan faktor-faktor yang mempengaruhi
dan seterusnya memilih kombinasi balm terbaik yang berpotensi dijadikan sebagai
TWB.
VII
TABLE OF CONTENTS
viii
CHAPTER TITLE
TITLE PAGE T
SUPERVISOR DECLARATION
STUDENT DECLARATION
DEDICATION
ACXNOWLEGDEMENTS
ABSTRACT
ABSTRAK
TABLE OF CONTENTS
LIST OF TABLES
LIST OF FIGURES
LIST OF SYMBOLS
LIST OF ABBREVIATIONS.
LIST OF APPENDICES
PAGE
1
11
111
iv
V
vi
vii
viii
xi
xi"
xv
xvi
xvii
1 INTRODUCTION
1.1 Project background
1
1.2 Problem Statements
2
1.3 Aim and Objectives
2
1.4 Project Scopes 3
ix
LITERATURE REVIEW
2.1 Tailor Welded Blanks 4
2.2. Automotive Panels 6
2.2.1 Hot Rolled (HR) Steel Sheet 7
2.2.1.1 SPHC 7
2.2.1.2 SAPH 370 8
2.2.2 Cold Rolled (CR) Steel Sheet 8
2.2.2.1 SPCC 9
2.2.2.2 SPCEN 9
2.2.3 Hot Dip Galvanized Steel Sheet 10
2.2.3.1 SGACC 10
2.3 Laser Beam Welding 11
2.4 Flat Rolling 14
2.4.1 Hot Rolling 15
2.4.2 Cold Rolling 16
2.5 Cost Consideration 17
2.6 Thickness of Sheet Metal 17
2.7 Stamping 17
2.8 Tensile 19
2.8.1 Tensile Test Machine 19
2.8.2 Hooke's Law 20
2.8.3 Modulus of Elasticity 20
2.8.4 Yield Strength 21
2.8.5 Strain 21
2.8.6 Ultimate Tensile Strength 21
3 METHODOLOGY
3.1 Introduction 22
3.2 Literature Review 24
3.3 Identify Process and Main Consent 24
3.4 Formulate Aim and Objectives 24
x
3.5 Method of investigation and Solution 25
3.5.1 Shearing 25
3.5.2 Ler Welding 27
3.5.3 Tensile Testing 30
3.6 Data collection 31
3.7 Comparison and Conclusion 31
4 RESULTS AND DISCUSSION
4.1 Introduction 32
4.2 Tensile Testing Results 32
4.2.1 Results of Base Metal Testing 33
4.2.2 Results of TWB Combinations Testing 34
4.3 Data Interpretations 38
4.3.1 Yield Strength 39
4.3.2 Tensile Strength 40
4.3.3 Elongation! Percent Strain 42
4.3.4 Overall Findings 43
4.4 Discussion 44
5 CONCLUSION AND RECOMMENDATIONS
5.1 Conclusion 46
5.2 Recommendation 46
REFERENCES 48
Appendices A-E 50-60
LIST OF TABLES
TABLE NO. TITLE PAGE
2.1 Mechanical properties and chemical composition of
RS 03131 hot rolled mild steel sheets and strips. 7
2.2 Comparison of JIS specification with similar standards 8
2.3 Mechanical properties and chemical composition of
MS G 3113 hot rolled steel sheet and strip for
automobile structural uses 8
2.4 Mechanical properties of MS 03141 cold rolled mild
steel sheets and strips 9
2.5 Chemical composition of MS G 3141 cold rolled mild
steel sheets and strips 10
2.6 Mechanical properties MS 03302 cold rolled hot-dip
Galvanized 11
2.7 Comparison of MS specification with similar standards 11
2.8 Effect of beam weaving with different amplitudes 14
3.1 List of specimen needed for the project 25
3.2 Laser Welding Parameters 28
3.3 Example of data collection table 31
xi
xii
4.1 Data Collections for the base metal 33
4.2 Data collections for the TWBs combination 38
LIST OF FIGURES
FIGURE NO. TITLE PAGE
2.1 Examples of typical use of tailor welded blanks 5
2.2 Steel door with tailor welded inner panel 5
2.3 Welding types used for Tailor Welded Blanks 6
2.4 Effect of filler wire use and Effects of filler wire
on weld hardness 13
2.5 Effect of planishing on weld hardness 14
2.6 Schematic outline of steel making from raw
material to by-products 15
2.7 TWBs are stamped using an ordinary press 18
3.1 Methodology flow chart 23
3.2 Dimension for shearing 26
3.3 NC shearing machine model MVS 6131 26
3.4 Sheared base metal specimens 27
3.5 An ORLaser laser beam welding machine model HTS 160 28
3.6 Laser welding process 29
3.7 Laser welded TWBs 29
xlii
3.8 TWBs tensile specimen dimension 30
3.9 Instron Universal Testing Model 3369 30
4.1 Fractured tensile specimens of TWBs 34
4.2 Comparison of TWBs yield strength to their base metals 39
4.3 Comparison of each TWBs yield strength 39
4.4 Comparison of TWBs tensile strength to their base metals 40
4.5 Comparison of each TWBs tensile strength 41
4.6. Comparison of TWBs elongation to their base metals 42
4.7 Comparison of each TWBs elongation 42
4.8 Overall findings 43
xiv
LIST OF SYMBOLS
A - Area
E - Modulus of Elasticity
e - Strain
F - Force
- Instantaneous length
L0 - Initial length
P - Pressure
AL - Change in length
£ - Strain
a - Stress
xv
xvi
LIST OF ABBREVIATIONS
CQ - Commercials Quality
CR - Cold Rolled
DDQ - Deep Draw Quality
HR - Hot Rolled
MS - Japanese industrial Standards
SAPH - Hot Rolled Steel Sheet for Automobile Structural Uses
SGACC - Hot Dip Galvanized Cold Roll Steel Sheet with Commercial
Quality
SPCC - Cold Rolled Steel Sheet with Commercial Quality
SPCEN - Cold Rolled Steel Sheet with Deep Drawing Quality
SPHC - Hot Rolled Steel Sheet with Commercial Quality
TWB - Tailor Welded Blanks
UTS - Ultimate Tensile Strength
YS - Yield Strength
LIST OF APPENDICES
APPENDIX TITLE PAGE
A Laser Welding Process 50
B Tensile Testing Process 51
C-i Tensile testing results SPCC-SPHC 52
C-2 Tensile testing results SPCC-SAPH 370 53
C-3 Tensile testing results SPCC-SGACC 54
C-4 Tensile testing results SPCEN-SPHC 55
C-5 Tensile testing results SPCEN-SAPH 370 56
C-6 Tensile testing results SPCEN-SGACC I 57
D-1 Laser welding machine technical data 58
D-2 Laser welding machine system features. 59
E Tailor Welded Blanks Door Inner Panel 60
xvii
CHAPTER 1
INTRODUCTION
1.1 Background
During the past two decades, government fuel conservation and safety
mandates along with environmental concerns have prompted the automotive industry
to design lighter cars for reduced fuel consumption, while improving the overall
structure of their vehicles for occupant safety. Corrosion protection was also much
improved during this period. These changes added to escalating manufacturing costs
at a time when the industry was struggling with a serious threat from global
competition.
To reduce weight and costs, alternative materials such as aluminum and
composite materials have been proposed and used for body panels, but none has
shown the versatility of steel. High strength steels, coated steels, laminated steels and
various thawing quality grades give steel the ability to meet most automotive
requirements.
In conventional door, normal inner panel and bracket are two different parts.
This method cost lots of money due to materials, dies, welding, assemblies, storage
and logistic. By combining these two components into a single blank those
difficulties can be reduce and allows automobiles to be manufactured more
efficiently. As a result, a process called tailor welded blank has been developed and
adapted by most automotive manufacturer nowadays. Not only door panel but also
2
others automotive panel employ this technique. So the aim of this study is to
investigate whether the materials chosen are suitable for automotive door inner panel
using the same concept of tailor welded blank.
1.2 Problem statements
i) The increasing demand for improved fuel efficiency and environmental
concerns make the automotive industry to industry to design lighter cars for
reduced fuel consumption.
ii) To reduce costs by using steels rather than highly cost alternative material.
J
1.3 Project Aim and Objectives
The aim of the project is to find the best joining materials for automotive
door inner panel to be used in Tailor Welded Blank (TWB) technique. The objectives
this study is to:
i) To compare the specimens aft, fter investigation in finding the best result.
ii) Propose new material combination to be applied in TWB process.
1.4 Project Scopes
This study will investigate on different type of material of joining by using
automotive steel panel that are SPCC, SPCEN, SPHC, SGACC, and SAPH 370. The
Panels grades are chosen from normal draw, extra draw, galvanized and structural
steels that typically used in automotive fields. To imitate the actual TWB panels,
method of welding two small panels with different thicknesses and properties will be
done. The testing will be done by using tensile test machine.
CHAPTER 2
LITERATURE REVIEW
2.1 Tailor Welded Blanks
Tailor welded blank, where multiple sheets of material are welded together
prior to the forming process. The differences in the material within a TWB can be in
the thickness, grade, or coating of the material (Kinsey and Cao, 2003).
Tailor Welded Blanks (TWB) are those in which sheets of different thickness
and/or properties are joined by laser, seam or plasma welding before press forming
(Anon, 2004).
Tailor-welded blanks (TWB) are comprised of two or more sheets of metal
which has dissimilar strength or thickness that are welded into a single blank. Tailor
Welded Blanks are stamped into automotive body panels and offer reduced part
weight and improved material use (Anon, 2004).
A tailor welded blank is composed of more than two materials with similar or
different strengths or thicknesses joined together to form a single part before the
forming operation. The main advantage of using a TWB is that it gives thicker or
stronger materials at critical parts of the sheet metal blank so as to increase the local
stiffness. This can also reduce the weight of automotive panels (Anon, 2003).
TW& D tDnrfmnev - S€(TWB) 2 DrOur- S& 3 4 R rner P& I 5 i• 6 Frat Dwar (2) I fuf Scr (4)
2
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Viiflhi?&i Frrri
/ MuIO \ C,cfrponnb!rt PiI
S^ Tt
Corer Am
- WeoE arEf
5
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IRo1Q1rent
/ T/f
FIDDJ Pin <:Z2^,,..
PANT Doc.r I,nc
From Doo r
Figure 2.1: Examples of typical use of Tailor Welded Blanks (Anon, 1995)
Figure 2.2: Steel door with tailor welded inner panel (Anon, 1999)
• ,r \
'S r)'/J s I
- \wj
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Types of welds which are used or have been considered for Tailor Welded Blanks include: