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

-PlIir Aircri'pi

Viiflhi?&i Frrri

/ MuIO \ C,cfrponnb!rt PiI

S^ Tt

Corer Am

- WeoE arEf

5

IRodyEde

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

rmw CIO

V

Pit i m

Odl

Types of welds which are used or have been considered for Tailor Welded Blanks include:

i) Laser Beam ii) Resistance Mash Seam iii) High-Frequency Induction iv) Electron Beam (non-vacuum)

(Anon, 1995)

r . ekft

L•:•

.'. C.

P.r

,'-:;• ,dTYI 'c(

/4 1 2.

tr bir, HIiiuc4iuu

Vep4h IWOr.om wsin; buff roan y eld n

Resiane roller moshiap seam weId1n

tofl•bEofl - •

'Cuff

Figure 2.3: Welding types used for Tailor Welded Blanks (Anon, 1995).

2.2 Automotive Panels

There are many types of automotive panels depends on process, grades,

coatings and thicknesses. One of the main producers of the material is coming from

Japan and Korea and also they are the main player in these industries. So, Japanese

Industrial Standards (JIS) is chosen for material grading through this entire project.

7

2.2.1 Hot Rolled (BR) Steel Sheet

Steel sheets produced right after hot rolling processes are called Hot Rolled

Steel Sheet. There are many types of Hot Rolled Steel Sheet for example SPHC,

SPHD, SPHE, SPFH, SAPH and etc. The abbreviations stated are named according

to Japanese Industrial Standard (JIS) grade. Come in various length, width and

thicknesses according to manufacturers.

2.2.1.1SPHC

SPHC is defined as Hot Rolled Steel Sheet with Commercial Quality (CQ).

This type of sheet is used for general purposes such as general forming and deep

drawing process.

SPHC in Japanese Industrial Standard (JIS) are coded under:

MS G 3131: 2005 - Hot rolled mild steel plates, sheets and strips.

Table 2.1: Mechanical properties and chemical composition of iTS 0 3131 hot rolled mild steel sheets and strips

Designationchemical Composition, %

Tensile Test

Tensile Strength N/mm2

Elongation, % Thickness 1.2mmto

1.6 mm excl. Mn r

SPPC 0.15 max, 060rax 0.05 ,0 max. 0.050 -max. 270 min. 27 min.

SPHD U.lOmax, 050max,, 0.040 max. 0.040 max. 276 mim 30,min.

SPHE O.lOmax, 0.50 max. 0.030 max. H 0.035 max. 270 min. 31 mm.

- SPHF 0.08 max. 0.6,0 max, 002$max. 0.025 max. 270 min. 37 min.

8

Table 2.2: Comparison of ills specification with similar standards

- JIS ASTM BS (DIN) ISO

G3131 SPHC A569 BS1449-HRI4 DIN 1614-StW22 ISO 3573-HRi23.4 BS 1449-HR15 ISO 631 7-HR1,2 3.4

H-RoUed Mild G131 SPHD A621 BS 1449 . HR3 DIN 1614StW23 Steel Sheets and Strip BS 1449-HR4

03131 SPHE A822 BS 1449-HR1 DIN 1614-StW24 BS 1449-HR2

2.2.1.2 SAPH 370

SAPH is defined as Hot Rolled Steel Sheet for Automobile Structural Uses.

This type of steel is outstanding in strength, drawability and weldability that are used

for automobile frame, wheels and other parts.

SAPH in Japanese Industrial Standard (JIS) are coded under:

MS G 3113:2006 - Hot rolled steel plate, sheet and strip for automobile

structural uses.

Table 2.3: Mechanical properties and chemical composition of ITS G 3113 hot rolled

steel sheet and strip for automobile structural uses

DesignationChemical Composition, %

Tensile Test

Yield Point, N/mm 2 Tensile Strength N/mm2

eongatlon. %

Thickness 6mmunder

Thickness 6mm to8nirnexcl.

I ThIckness 8mm lol4mmlnci.

Thickness 1.6mm to

2.Ommexcl.

Thickness2.0 mm to

I 2.Smmexcl. P 1 S SAPH310 0.040maxJ 0.040max. (185 min.) I (185mm.) I (175 min.) 310 min. 33 min. 34 min.

SAPH370 0.040max.I 0.040max. 225 min. I 225 min. I 215 min. 370 min. 32mm. I 33 min.

SAPH400 0.040 max. I 0.040 max. 255 mm. 235 mm. I 235 mm. 400 mm. 31 mm. 1 32 mm.

SAPH440 0.040 max. 0.040 max. 305 mm. 1 295 mm. I 275 mm. 440 mm. 29 mm. I 30 mm.

2.2.2 Cold Rolled (CR) Steel Sheet

Steel sheets produced after cold rolling processes are called Cold Rolled Steel

Sheet. There are many types of Cold Rolled Steel Sheet for example SPCC, SPCC-T,

SPCD, SPCE, SPCEN, SPFC (ITS grade) and etc. These types of steel are applied to

various fields including automotives, electric household appliances, and furniture

office equipment.

2.2.2.1 SPCC

SPCC defined as Cold Rolled Steel Sheet with Commercial Quality (CQ).

These types of steel are best suited for automobiles, electrical appliances, etc due to

wider workable range.

SPCC in Japanese Industrial Standard (JIS) is coded under:

MS G 3141: 2005— Cold-reduced rolled carbon steel sheets and strips

2.2.2.2 SPCEN

SPCEN is defined as Cold Rolled Steel Sheet with Deep Drawing Quality

(DDQ). These types of steel are best suited for automobiles, electrical appliances, etc

due to wider workable range.

SPCEN in Japanese Industrial Standard (JTS) are coded same as SPCC:

MS G 3141: 2005 - Cold-reduced rolled carbon steel sheets and strips

Table 2.4: Mechanical properties of JIS G 3141 cold rolled mild steel sheets and

strips.

Type ClassificationTest

Designation or

Tension test

Yes gt1n reissis grisi- Elongation mm. %

0.25t 0.25t 0.60t<1.0

Standard cold-rolled steel

Commercial quality SPCC S,84,

2, 1 - -

SPCCT 270 36 Drawing quality SPCD S. (240) 270S 38

sheets and cots IJISG3141t

_

Deep drawing quality

SPCE S (220) 270 40 SPCF S (210) 270 42

Exbs-ep&awitogiatty SPCG S (190) 270 44

lEll

Table 2.5: Chemical composition of MS G 3141 cold rolled mild steel sheets and

strips

Designation C Mn P S

SPCC 0.15 0.60 = 0.100 0.050

SPCD 012 050 0040 0040 SPCE ZO.10 0.45 0.030 0.030

SPCF 0.08 0.45 0.030 0.030

SPCG'' 0.02 0.25 0.020 0.020

2.2.3 Blot Dip Galvanized Steel Sheet

Hot-dip galvanized steel sheets are produced by applying a coating of molten

zinc to the surface of hot-rolled or cold-rolled base material by the "hot dip"

galvanizing process. There are much type of grade for example SGAHC, SGACC,

SGACD, and etc. Having an excellent corrosion resistance, these products are used

in a wide range of fields such as automotive, electric appliance, and building material

applications.

2.2.3.1 SGACC

SGACC is defined as Hot Dip Galvanized Cold Roll Steel Sheet with

Commercial Quality (CQ). This type of steel is use inner and outer panel of

automobiles. Also use as fuel tanks.

SGACC in Japanese Industrial Standard (JTS) are coded under:

MS G 3302: 2005 - Hot-dip zinc-coated steel sheets and coils

11

Table 2.6: Mechanical properties JIS G 3302 cold rolled hot-dip galvanized

ThicknessYield Point

.Tensile Strength

Elongation

mm Classification mm

mm. KglrrO

. mm. ...... 0.4026and 11602$and 1.025andKg/m2 over, under over, under Over, under • --. - ________ 0.60 1_0 1.6

SGCC :. ...., -

SGCD1 28 34 35 37 9GCD2 28 35 38 39 SGCD3 28 38 40 41

si: .: ..• . .... ., ...1.J • .

28 .38 . 40 41

Table 2.7: Comparison of JIS specification with similar standards

Classification /Standards 03302STM

EN10142 89.

Commarciat SGCC A526 A653-CQ DX51D Lock forming SGCDI 4527 4653-LEO

Drawing SGCO2 4528 AL 653-DQ 0X52D Deepdrawing SGCO3 DX53D

Non Aging Deep Drawing SOCO 3M 4542 A653-DOSK 0X54D Non Aging Extra Deep

Drawing

2.3 Laser-Beam Welding (LBW)

To produce a fusion weld, Laser-beam Welding utilizes a high-power laser

beam as the source of heat. It has high energy density and, therefore, deep-

penetrating capability because the beam can be focused onto a very small area. The

beam can be directed, shaped, and focused precisely on the workpieces.

Laser-beam Welding creates good quality welds with minimum shrinkage

and distortion. This type of welds have good strength and generally ductile and free

of porosity. The process can be automated and can be used on a variety of materials

thickness of up to 25mm (1 in.). It is particularly effective in thin workpices.

Laser welding techniques nowadays are highly developed resulting very

strong weld joints. Significant flexibility in product design, structural stiffness, crash