EFFECT OF CUTTING SPEED AND DEPTH OF CUT ON SURFACE ROUGHNESS OF OIL-QUENCHED MILD STEEL YEONG CHOY HUEY UNIVERSITI MALAYSIA PAHANG

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1 EFFECT OF CUTTING SPEED AND DEPTH OF CUT ON SURFACE ROUGHNESS OF OIL-QUENCHED MILD STEEL YEONG CHOY HUEY UNIVERSITI MALAYSIA PAHANG

2 UNIVERSITI MALAYSIA PAHANG BORANG PENGESAHAN STATUS TESIS JUDUL: Saya EFFECT OF CUTTING SPEED AND DEPTH OF CUT ON SURFACE ROUGHNESS OF OIL-QUENCHED MILD STEEL SESI PENGAJIAN: 2008/2009 YEONG CHOY HUEY ( ) (HURUF BESAR) mengaku membenarkan tesis (Sarjana Muda/Sarjana /Doktor Falsafah)* ini disimpan di Perpustakaan dengan syarat-syarat kegunaan seperti berikut: 1. Tesis adalah hakmilik Universiti Malaysia Pahang (UMP). 2. Perpustakaan dibenarkan membuat salinan untuk tujuan pengajian sahaja. 3. Perpustakaan dibenarkan membuat salinan tesis ini sebagai bahan pertukaran antara institusi pengajian tinggi. 4. **Sila tandakan ( ) SULIT TERHAD (Mengandungi maklumat yang berdarjah keselamatan atau kepentingan Malaysia seperti 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: (TANDATANGAN PENULIS) (TANDATANGAN PENYELIA) Alamat Tetap: 4C-3-13 LRG SEMARAK API 1 SALWANI BT. MOHD SALLEH BDR BARU AYER ITAM ( Nama Penyelia ) PULAU PINANG Tarikh: 20 NOVEMBER 2009 Tarikh: : 20 NOVEMBER 2009 CATATAN: * Potong yang tidak berkenaan. ** Jika tesis ini SULIT atau TERHAD, sila lampirkan surat daripada pihak berkuasa/organisasi berkenaan dengan menyatakan sekali tempoh tesis ini perlu dikelaskan sebagai atau TERHAD. Tesis dimaksudkan sebagai tesis bagi Ijazah doktor Falsafah dan Sarjana secara Penyelidikan, atau disertasi bagi pengajian secara kerja kursus dan penyelidikan, atau Laporan Projek Sarjana Muda (PSM).

3 UNIVERSITI MALAYSIA PAHANG FACULTY OF MECHANICAL ENGINEERING We certify that the project entitled effect of cutting speed and depth of cut on surface roughness of oil-quenched mild steel is written by Yeong Choy Huey. We 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. We herewith recommend that it be accepted in partial fulfillment of the requirements for the degree of Bachelor of Mechanical Engineering with Manufacturing Engineering. (Dr.Daw Thet Thet Mon) Examiner Signature

4 EFFECT OF CUTTING SPEED AND DEPTH OF CUT ON SURFACE ROUGHNESS OF OIL-QUENCHED MILD STEEL YEONG CHOY HUEY Report submitted in partial fulfilment of the requirements for the award of Bachelor of Mechanical Engineering with Manufacturing Engineering Faculty of Mechanical Engineering UNIVERSITI MALAYSIA PAHANG NOVEMBER 2009

5 ii 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: SALWANI BT. MOHD SALLEH Position: LECTURER OF FACULTY OF MECHANICAL ENGINEERING Date: 20 NOVEMBER 2009 Signature Name of Co-Supervisor: LEE GIOK CHUI, SMP, KMN Position: LECTURER OF FACULTY OF MECHANICAL ENGINEERING Date: 20 NOVEMBER 2009

6 iii STUDENT S DECLARATION I hereby declare that the work in this project entitled effect of cutting speed and depth of cut on surface roughness of oil-quenched mild steel is my own except for quotations and summaries which have been duly acknowledged. The project has not been accepted for any degree and is not concurrently submitted for award of other degree. Signature Name : YEONG CHOY HUEY ID Number : ME06023 Date : 20 NOVEMBER 2009

7 vii TABLE OF CONTENTS SUPERVISOR S DECLARATION STUDENT S DECLARATION ACKNOWLEDGEMENT ABSTRACT ABSTRAK TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES LIST OF SYMBOLS LIST OF ABBREVIATION Page ii iii iv v vi vii xi xii xiv xv CHAPTER 1 INTRODUCTION 1.1 Project Background Problem Statement Project Objectives Scopes of Project 4 CHAPTER 2 LITERATURE REVIEW 2.1 Introduction Introduction to Steel Classification of Steel Applications of Steel Testing of Materials Hardness Test Brinell Hardness Test Rockwell Hardness Test 9

8 viii 2.6 Heat Treatment of Carbon Steel Direct Hardening Steel Color vs Temperature Iron-Carbon (Fe-C) Equilibrium Cooling of Plain Carbon Steel Formation of Fe-C by Rapid Quenching Continuous-Cooling Transformation Diagram for Eutectoid Plain Carbon Steel Quenching Medium Machinability Lathes and Lathe Operations Cutting Speeds Feed Depth of Cut Material Removal Rate Selection of Cutting Tool Materials Conclusion 22 CHAPTER 3 METHODOLOGY 3.1 Introduction Flow Chart Material Preparation Heat Treatment Oil-Quenching Rockwell Hardness Test Machining Parameters Constant Parameters Selection of Cutting Speed Selection of RPM and Depth of Cut Design of Experiment: Taguchi and Orthogonal Array Lathe Machining Selection of Cutting Tool Material Data Analysis 34

9 ix Surface Roughness Measurement Prediction of Surface Roughness with RSM Analysis of Variance (ANOVA) Validation Test with Polynomial Trend Line Equation Determination of Oil-Quenched Mild Steel Chemical Composition Grinding Process Chemical Composition Determination with Bench Top Arc / Spark Spectrometer Machinability Parameters and Formulas Expected Results 41 CHAPTER 4 RESULTS AND DISCUSSIONS 4.1 Introduction Results for Surface Roughness Values with respect to Depth of Cut and Cutting Speed Effect of Cutting Speed on Oil-Quenched Mild Steel from Graphical Analysis Effect of Depth of Cut on Oil-Quenched Mild Steel from Graphical Analysis Prediction of Surface Roughness with RSM Prediction of Surface Roughness with RSM First-Order Model Prediction of Surface Roughness with RSM Second-Order Model Comparison between Experimental Ra and Predicted Ra Analysis of Variance (ANOVA) Validation with Polynomial Trend Line Equation Validation Test to Evaluate Optimum Cutting Speed Validation Test to Evaluate Optimum Depth of Cut Hardness Test using Rockwell Hardness Tester Chemical Composition Analysis Relationship between Cutting Speed and Depth of Cut on Surface Roughness Relationship between Cutting Speed and Surface Roughness 71

10 x Relationship between Depth of Cut and Surface Roughness 71 CHAPTER 5 CONCLUSION AND RECOMMENDATIONS 5.1 Introduction Conclusion Recommendations 74 REFERENCES 76 APPENDICES A1 Results generated for RSM First-Order Model 78 A2 Results generated for RSM Second-Order Model 80 A3 Analysis of Variance with Microsoft Excel 82 B1 Gantt Chart / Project Schedule for FYP 1 83 B2 Gantt Chart / Project Schedule for FYP 2 84

11 xi LIST OF TABLES Table No. Page 2.1 Typical applications of carbon steels Various Rockwell scales Types of quenching media and description Steel color vs temperature Parameters for AISI 1015, 1020, 1023, 1025 and 1026 grades RPM and depth of cut selection from low level to high level Orthogonal array design table Result for surface roughness values obtained with respect to changes in depth of cut and cutting speed Comparison between experimental and predicted Ra for first-order model Comparison between experimental and predicted Ra for second- Order model Analysis of variance for first-order equation Estimated regression coefficient for Ra (first-order) Analysis of variance for second-order equation Estimated regression coefficient for Ra (second-order) Analysis of variance using Microsoft Excel Result of validation test using trend line equation for surface Surface roughness wrt. three different spindle speed values Result of validation test using trend line equation for surface Roughness wrt. five different depth of cut values Hardness values (HB) of before and after oil-quenched mild steel Converted hardness values (HB) of before and after oil-quenched steel Chemical composition of oil-quenched mild steel 70

12 xii LIST OF FIGURES Figure No. Page 2.1 Steel color vs temperature The iron-carbon phase diagram Effect of carbon content on the martensite-transformation start Temperature for iron-carbon alloys Continuous-cooling diagram for a plain-carbon eutectoid steel Variation in microstructure of eutectoid plain-carbon steel by Continuously cooling at different rates General view of a typical lathe showing various components Band saw machine Cutting using band saw machine Heating mild steel with welding heat source Heat treated mild steel quenched in motor oil The steel was held until oil stop bubbling Oil-quenched mild steel Rockwell hardness tester Conventional lathe machine Surface roughness tester, perthometer Grinding machine Bench Top Arc / Spark Spectrometer Specimen position during spark After spark on specimen 39

13 xiii 4.1 Average surface roughness vs. cutting speed wrt. various depth of cut values Average surface roughness vs. depth of cut wrt. various RPM values Normal probability plot for Ra data Contour plot of Ra versus depth of cut and RPM Normal probability plot for Ra data for second-order model Contour plot of Ra vs. depth of cut and RPM Comparison between experimental and predicted Ra values Average surface roughness vs. depth of cut wrt. 490 RPM Average surface roughness vs. depth of cut wrt. 810 RPM Average surface roughness vs. depth of cut wrt RPM Average surface roughness vs. RPM wrt. 0.1mm depth of cut Average surface roughness vs. RPM wrt. 0.2mm depth of cut Average surface roughness vs. RPM wrt. 0.3mm depth of cut Average surface roughness vs. RPM wrt. 0.4mm depth of cut Average surface roughness vs. RPM wrt. 0.5mm depth of cut Chart of Brinell Hardness (HB) vs. number of test performed for nonquenched and oil-quenched mild steel 69

14 xiv LIST OF SYMBOLS R a f v N MRR average surface roughness value feed rate Cutting speed in m/min or mm/min Spindle speed in RPM Material Removal Rate

15 xv LIST OF ABBREVIATIONS Al ANOVA As B Bi BUE C Ca Co Cr Cu Fe Ni Nb Mn Mo P Pb RPM RSM S Aluminium Analysis of Variance Arsenic Boron Bismuth Built-up edge Carbon Calcium Cobalt Chromium Copper Iron Nickel Niobium Manganese Molybdenum Phosporus Lead Revolution per Minute Response Surface Methodology Sulphur

16 xvi Si Sn V Zr Silicon Tin Vanadium Zirconium