investigation of machining performance of coated carbide...
TRANSCRIPT
INVESTIGATION OF MACHINING PERFORMANCE OF COATED CARBIDE BY
MURAKAMI SURFACE PRETREATMENT
KHAIRUL AZMI BIN MOHD MAWARDZI
A report submitted in partial fulfillment of
The requirements for the award of the degree of
Bachelor of Mechanical Engineering
With Manufacturing Engineering
Faculty of Mechanical Engineering
Universiti Malaysia Pahang
JUNE 2012
vi
ABSTRACT
Tungsten carbide is the most widely used material for cutting tools. Due to extreme
demands higher tool life several types of coating have been introduced to prolong the
service time which include diamond coating. However cobalt binder in tungsten
carbide prevents diamond to adhere well on the substrate and its content at the outer
surface should be reduce to below 1%. Pretreatments have been studied by many
researchers. But to date poor adhesion of diamond coating still an issue. In this work
a murakami pretreatment was used to etch tungsten carbide at the surface of the
substrate in order to solve poor adhesion problem. First step with Murakami's reagent
20 minutes and the second step of the process were carried out by etching in a
solution of hydrochloric acid (45 seconds). The effect of murakami pretreatments on
Co cemented tungsten carbide samples were study in term of surface morphology,
surface roughness, and cobalt removal from the surface was examined. Based on the
experimental, the following conclusions can be withdrawn. It is found that murakami
suface pretreatment affecting the final surface roughness of substrate. Murakami
pretreatment able to strengthened the diamond coating adhesion by modifying the
surface roughness. The wear resistance of coated tungsten carbide was higher than
uncoated tungsten carbide. Cutting tool with coated tungsten carbide produced better
work piece’s surface finish as compared to uncoated cutting tool. It was also further
improved when pretreatment (murakami) was used.
vii
ABSTRAK
Tungsten karbida adalah bahan yang paling banyak digunakan dalam alat-alat
pemotongan. Disebabkan oleh permintaan yang tinggi terhadap alatan pemotong
yang berjangka hayat lama, kaedah saduran diperkenalkan untuk meningkatkan masa
penggunaannya termasuklah saduran berlian. Walaubagaimanapun, pengikat kobalt
di dalam tungsten karbida menghalang berlian daripada melekat dengan sempurna
pada substrak dan kandungannya perlu dikurangkan kepada bawah daripada satu
peratus. Kaedah langkah pra-rawatan telah dipelajari oleh ramai penyelidik sebelum
ini. Tetapi masalah berlian yang tidak melekat dengan baik masih menjadi isu.
Didalam kajian ini,pra-rawatan digunakan untuk menghakis tungsten karbida pada
permukaan substrak dalam usaha menyelesaikan masalah perekatan yang tidak
sempurna ini. Langkah pertama adalah dengan reagen Murakami 20 minit dan
langkah kedua dalam proses ini ialah pengakisan menggunakan asid hidroklorik (45
saat). Kesan daripada eksperimen ini terhadap tungsten karbida semen dikaji dari
segi morfologi permukaan, kekasaran permukaan dan penyingkiran kobalt dari
permukaan. Berdasarkan eksperimen ini, kesimpulannya didapati bahawa pra-
rawatan permukaan mempengaruhi kekasaran permukaan akhir substrate.Murakami
dapat mengukuhkan lekatan salutan berlian dengan mengubah rintangan permukaan.
Tungsten karbida bersalut adalah lebih tinggi daripada tungsten karbida tidak
bersalut, alat pemotongan tungsten karbida bersalut menghasilkan kemasan
permukaan benda kerja yang lebih baik berbanding alat pemotong tidak bersalut. Ia
juga menjadi lebih baik apabila prarawatan (Murakami) telah digunakan.
viii
TABLE OF CONTENTS
Page
EXAMINER’S DECLARATION ii
SUPERVISOR’S DECLARATION iii
STUDENT’S DECLARATION iv
ACKNOWLEDGEMENTS v
ABSTRACT vi
ABSTRAK vii
TABLE OF CONTENTS viii
LIST OF TABLES x
LIST OF FIGURES xi
LIST OF SYMBOLS xii
LIST OF ABBREVIATIONS xiii
CHAPTER 1 INTRODUCTION 1
1.1 Introduction 1
1.2 Problem Statement 2
1.3 Objectives of the Research 2
1.4 Scope of project
3
CHAPTER 2 LITERATURE REVIEW 4
2.1 Introduction 4
2.1.1 Introduction of investigation 4
2.1.2 Introduction of machining performance 5
2.1.3 Introduction of coated carbide
2.1.4 Introduction of turning machine
2.1.5 Introduction of CVD Coating
2.1.6 Introduction of chemical pretreatment
2.1.7 Introduction of murakami surface pretreatment
5
6
9
10
11
2.2 Summary of literature review 13
CHAPTER 3 METHODOLOGY
17
3.1 Introduction 17
ix
APPENDICES 38
A 38
3.2 Surface pretreatment
3.3 CVD coating methods
3.4 Turning Experiment
3.5 Cutting tools characterization
3.5.1 Surface microstructure
3.5.2 Wear resistant
3.5.3 Hardness test
3.5.4 Surface roughness
3.5.5 Workpiece chips
18
19
20
21
21
22
23
23
24
CHAPTER 4 RESULT AND DISCUSSION
25
4.1 Introduction 25
4.2 Surface microstructure 25
4.3 Effect of murakami pre-treatment to coated carbide
machining performance
4.4 Effect of murakami surface pre-treatment to coated
carbide by Vickers micro hardness
27
29
4.5 Effect of murakami surface pre-treatment to
tungsten carbide surface roughness
31
4.6 Result of chips formation
33
CHAPTER 5 CONCLUSION AND RECOMANDATION
35
5.1 Conclusions 35
5.2 Recommendation 35
REFERENCES 36
1 × ENTER (1.5 line spacing)
x
LIST OF TABLES
Table No.
Title Page
2.1 Capability of turning 8
3.1 Parameter for ASTM B777-7 21
xi
LIST OF FIGURES
Figure No.
Title Page
2.1 Manual lathe machine 7
2.2 Schematic view of the CVD chamber 9
2.3 SEM micrographs of fine grain substrates 12
3.1 Methodology flow chart 18
3.2 Schematic view of the CVD chamber 19
3.3 Shun Chuan turning machine model ERL13370 20
3.4 Scanning Electron Microscope (SEM) 22
3.5 Optical Measurement Microscope 22
3.6 Vickers Hardness Model: MATSUZAWA MMT-X7 23
4.1 Surface morphologies of tungsten carbide cutting tools 26
4.2 Graph length of wear vs cutting length 29
4.3 Graph hardness of cutting tool 31
4.4 Graph effect of surface pretreatment on surface roughness 32
4.5 Type of chips 34
xii
LIST OF SYMBOLS
µm Micrometer
% Percentage
g/cm 3 Gram per centimeter cube
kg/m 3 Kilogram per meter cube
Gpa Giga Pascal
Mpa Mega Pascal
c Thermal Expansion Coefficient
K Kelvin
HV Hardness Vickers
xiii
LIST OF ABBREVIATIONS
CVD Chemical Vapour Deposition
PVD Physical Vapour Deposition
Ti-6Al-4V ELI Titanium alloy alpha-beta Extra Low Interstitial
HF Hydrofluoric
SEM Scanning Electron Microscope
WC Tungsten Carbide
ii
UNIVERSITI MALAYSIA PAHANG
FACULTY OF MECHANICAL ENGINEERING
I certify that the project entitled “investigation of machining performance of coated
carbide by murakami surface pretreatment” is written by Khairul Azmi Bin Mohd
Mawardzi. I have examined the final copy of this project and in our opinion; it is
fully adequate in terms of scope and quality for the award of the degree of Bachelor
of Engineering. I here with recommend that it be accepted in partial fulfillment of the
requirements for the degree of Bachelor of Mechanical Engineering with
Manufacturing Engineering.
Signature : ……………………..
Name of Examiner : Dr. Noraini Mohd Razali
Position : Lecturer
Date :
iii
SUPERVISOR’S DECLARATION
I hereby declare that I have checked this project and in my opinion, this project is
adequate in terms of scope and quality for the award of the degree of Bachelor of
Mechanical Engineering with Manufacturing Engineering.
Signature : ……………………..
Name of Supervisor :Dr. Siti Rabiatull Aisha Idris
Position :Lecturer
Date :
iv
STUDENT’S DECLARATION
I hereby declare that this report entitled “investigation of machining performance of
coated carbide by murakami surface pretreatment”is the result of my own research
except as cited in the references. The report has not been accepted for any degree and
is not concurrently submitted in candidature of any other degree.
.
Signature : ……………………..
Name : Khairul Azmi Bin Mohd Mawardzi
ID Number : ME 08068
Date : 22th
of June 2012
v
ACKNOWLEDGEMENT
I would like praise to almighty God who has given me the strength and
potency to complete this research. In particular, I want to express my sincere
appreciation to my supervisor, Dr. Siti Rabiatull Aisha Binti Idris for her
encouragement, motivation, guidance, and critics in completing this thesis. I am also
very thankful to all staff, for providing the guideline, advice, and friendship. Without
their continued support and interest, this report would not have been the same as
presented here. They are always guiding me in doing my research and writing this
project report and God bless all their sacrifices and efforts. As well I would like to
extend my sincere appreciation to all the staffs in Laboratory for their support and
guidance in performing the laboratory tasks. I also would like to thank all my
lecturers for their advice and motivation. I will remember and implement them in the
future. Finally, I want to thank to all of my friends for their aid in finishing this
research.
vi
ABSTRACT
Tungsten carbide is the most widely used material for cutting tools. Due to extreme
demands higher tool life several types of coating have been introduced to prolong the
service time which include diamond coating. However cobalt binder in tungsten
carbide prevents diamond to adhere well on the substrate and its content at the outer
surface should be reduce to below 1%. Pretreatments have been studied by many
researchers. But to date poor adhesion of diamond coating still an issue. In this work
a murakami pretreatment was used to etch tungsten carbide at the surface of the
substrate in order to solve poor adhesion problem. First step with Murakami's reagent
20 minutes and the second step of the process were carried out by etching in a
solution of hydrochloric acid (45 seconds). The effect of murakami pretreatments on
Co cemented tungsten carbide samples were study in term of surface morphology,
surface roughness, and cobalt removal from the surface was examined. Based on the
experimental, the following conclusions can be withdrawn. It is found that murakami
suface pretreatment affecting the final surface roughness of substrate. Murakami
pretreatment able to strengthened the diamond coating adhesion by modifying the
surface roughness. The wear resistance of coated tungsten carbide was higher than
uncoated tungsten carbide. Cutting tool with coated tungsten carbide produced better
work piece’s surface finish as compared to uncoated cutting tool. It was also further
improved when pretreatment (murakami) was used.
vii
ABSTRAK
Tungsten karbida adalah bahan yang paling banyak digunakan dalam alat-alat
pemotongan. Disebabkan oleh permintaan yang tinggi terhadap alatan pemotong
yang berjangka hayat lama, kaedah saduran diperkenalkan untuk meningkatkan masa
penggunaannya termasuklah saduran berlian. Walaubagaimanapun, pengikat kobalt
di dalam tungsten karbida menghalang berlian daripada melekat dengan sempurna
pada substrak dan kandungannya perlu dikurangkan kepada bawah daripada satu
peratus. Kaedah langkah pra-rawatan telah dipelajari oleh ramai penyelidik sebelum
ini. Tetapi masalah berlian yang tidak melekat dengan baik masih menjadi isu.
Didalam kajian ini,pra-rawatan digunakan untuk menghakis tungsten karbida pada
permukaan substrak dalam usaha menyelesaikan masalah perekatan yang tidak
sempurna ini. Langkah pertama adalah dengan reagen Murakami 20 minit dan
langkah kedua dalam proses ini ialah pengakisan menggunakan asid hidroklorik (45
saat). Kesan daripada eksperimen ini terhadap tungsten karbida semen dikaji dari
segi morfologi permukaan, kekasaran permukaan dan penyingkiran kobalt dari
permukaan. Berdasarkan eksperimen ini, kesimpulannya didapati bahawa pra-
rawatan permukaan mempengaruhi kekasaran permukaan akhir substrate.Murakami
dapat mengukuhkan lekatan salutan berlian dengan mengubah rintangan permukaan.
Tungsten karbida bersalut adalah lebih tinggi daripada tungsten karbida tidak
bersalut, alat pemotongan tungsten karbida bersalut menghasilkan kemasan
permukaan benda kerja yang lebih baik berbanding alat pemotong tidak bersalut. Ia
juga menjadi lebih baik apabila prarawatan (Murakami) telah digunakan.
viii
TABLE OF CONTENTS
Page
EXAMINER’S DECLARATION ii
SUPERVISOR’S DECLARATION iii
STUDENT’S DECLARATION iv
ACKNOWLEDGEMENTS v
ABSTRACT vi
ABSTRAK vii
TABLE OF CONTENTS viii
LIST OF TABLES x
LIST OF FIGURES xi
LIST OF SYMBOLS xii
LIST OF ABBREVIATIONS xiii
CHAPTER 1 INTRODUCTION 1
1.1 Introduction 1
1.2 Problem Statement 2
1.3 Objectives of the Research 2
1.4 Scope of project
3
CHAPTER 2 LITERATURE REVIEW 4
2.1 Introduction 4
2.1.1 Introduction of investigation 4
2.1.2 Introduction of machining performance 5
2.1.3 Introduction of coated carbide
2.1.4 Introduction of turning machine
2.1.5 Introduction of CVD Coating
2.1.6 Introduction of chemical pretreatment
2.1.7 Introduction of murakami surface pretreatment
5
6
9
10
11
2.2 Summary of literature review 13
CHAPTER 3 METHODOLOGY
17
3.1 Introduction 17
ix
APPENDICES 38
A 38
3.2 Surface pretreatment
3.3 CVD coating methods
3.4 Turning Experiment
3.5 Cutting tools characterization
3.5.1 Surface microstructure
3.5.2 Wear resistant
3.5.3 Hardness test
3.5.4 Surface roughness
3.5.5 Workpiece chips
18
19
20
21
21
22
23
23
24
CHAPTER 4 RESULT AND DISCUSSION
25
4.1 Introduction 25
4.2 Surface microstructure 25
4.3 Effect of murakami pre-treatment to coated carbide
machining performance
4.4 Effect of murakami surface pre-treatment to coated
carbide by Vickers micro hardness
27
29
4.5 Effect of murakami surface pre-treatment to
tungsten carbide surface roughness
31
4.6 Result of chips formation
33
CHAPTER 5 CONCLUSION AND RECOMANDATION
35
5.1 Conclusions 35
5.2 Recommendation 35
REFERENCES 36
1 × ENTER (1.5 line spacing)
x
LIST OF TABLES
Table No.
Title Page
2.1 Capability of turning 8
3.1 Parameter for ASTM B777-7 21
xi
LIST OF FIGURES
Figure No.
Title Page
2.1 Manual lathe machine 7
2.2 Schematic view of the CVD chamber 9
2.3 SEM micrographs of fine grain substrates 12
3.1 Methodology flow chart 18
3.2 Schematic view of the CVD chamber 19
3.3 Shun Chuan turning machine model ERL13370 20
3.4 Scanning Electron Microscope (SEM) 22
3.5 Optical Measurement Microscope 22
3.6 Vickers Hardness Model: MATSUZAWA MMT-X7 23
4.1 Surface morphologies of tungsten carbide cutting tools 26
4.2 Graph length of wear vs cutting length 29
4.3 Graph hardness of cutting tool 31
4.4 Graph effect of surface pretreatment on surface roughness 32
4.5 Type of chips 34
xii
LIST OF SYMBOLS
µm Micrometer
% Percentage
g/cm 3 Gram per centimeter cube
kg/m 3 Kilogram per meter cube
Gpa Giga Pascal
Mpa Mega Pascal
c Thermal Expansion Coefficient
K Kelvin
HV Hardness Vickers
xiii
LIST OF ABBREVIATIONS
CVD Chemical Vapour Deposition
PVD Physical Vapour Deposition
Ti-6Al-4V ELI Titanium alloy alpha-beta Extra Low Interstitial
HF Hydrofluoric
SEM Scanning Electron Microscope
WC Tungsten Carbide
1
CHAPTER 1
INTRODUCTION
1.1 INTRODUCTION
Machining process play an important role in product making and widely use in
manufacturing industries. Machining is the process of removing materials from excess
and unwanted stock by use of machine tools and converting them into a usable parts. All
of these related to the metal cutting. Therefore the characteristic of cutting tools need to
be consider during in machining operation in order to get a good quality of product in
time, and can reduce the production cost. Cemented tungsten carbide is the most widely
used material for cutting tools. Due to extreme demands higher tool life several types of
coating have been introduced to prolong the service time which include diamond
coating. The study of CVD diamond coatings can be expected to significantly prolong
the lifetime of coated tools during cutting and milling. The Co in the hard metal binder
phase can Influence the chemical vapour deposition of diamond. Co vapour pressure,
surface migration, and carbon solubility are the main parameters influencing diamond
nucleation and growth and coating adhesion. Pre-treatment procedures are usually aimed
at decrease the Co in the substrate surface by select chemical etching. In this paper the
special surface pre-treatment procedure reported in the patent was investigated. After
small amounts of WC are removed from the hard metal substrate surface by etching with
Murakami solution (K3[Fe(CN)6] n KOH), the remaining Co binder network is treated
with H2SO4/H2O2 solution. The effects of this surface treatment with respect to diamond
growth rate, morphology and adhesion of the deposited coating on the substrates were
investigated.
2
1.2 PROBLEM STATEMENT
Performance of turning machine almost depending in how fast the machine can
cut the work piece, its meant more faster the turning machine process material more
finish product are produce in a period of time and the productivity of the machine are
high. High productivity needed high rate of metal removal, so it will reduce
manufacturing cost and operation time. Although the faster process is needed, it did not
guarantee the quality of the produce good in term of surface roughness. Customer
always prefer to a quality product and the quality of work piece machined surface and its
integrity are most depend on tool wear and it directly depend on life of the tool.
Moreover, despite having the target of achieving optimum finishing with the shortest
possible time one must take into account the consideration the quality of surface
roughness, so that the complete finishing operation can be carried out with just one tool,
avoiding the intermediate stops in order to change the tool due to its wear. Eventually,
sudden failure of cutting tools lead to loss of productivity, rejection of parts and
consequential economic losses. Selection of cutting tools and cutting conditions
represents. Plus tool wear/tool life is an important aspect commonly considered in
evaluating the performance of a machining process. In this research, the main objective
is to study the effect and performance of coated cutting tools with Murakami surface
pretreatment in order to get the best quality of work piece surface roughness while using
turning machine.
1.3 OBJECTIVE OF THE RESEARCH
These are the objectives for this research:
(a) To determine the effect of the murakami pretreatment onto tungsten carbide‘s
surface morphology prior to coating.
(b) To determine the effect of machining performance of tungsten carbide on
titanium (focusing on size and shape of the chip).
3
(c) To evaluate the effect of tungsten carbide’s wear resistance using coated and
uncoated tungsten carbide.
1.4 SCOPE OF PROJECT
The scope of this research can be divided into three main parts:
a) Murakami surface pretreatment of the cutting tools
-The tungsten carbide cutting tools will be etched (soaked) in murakami
solution.
b) Coating the cutting tools
-The cutting tools will be coated by chemical vapor deposition (CVD)
technique.
c) Machining (testing the cutting tools)
-The cutting tools will be testing by using turning machine with titanium
workpiece based on the specified parameters.