A Textbook on Production Engineering

CONTENTS
1. Metrology
1.1 Introduction................................................ 1
1.2 Accuracy and Precision ............................ 5
1.3 Interchangeability ..................................... 6
1.4 Selective Assembly ................................... 7
1.5 Limits, Fits and Tolerances ........................ 8
1.6 Allowance ................................................ 10
1.6.1 Width of Tolerance Zone.............. 10
1.7 Tolerance Sink ......................................... 17
1.8 Design of Limit Gauges........................... 18
1.9 Violation of Taylor’s Principle in Gauge
Design ..................................................... 20
1.10 Gauge Material........................................ 20
1.11 Slip Gauges............................................. 22
1.12 Angle Blocks............................................ 23
1.13 Sine Bar................................................... 23
1.14 Precision Ball Measurement .................... 24
1.15 Vernier Calipers and Micrometer ............ 26
1.16 Types of Errors......................................... 26
1.17 Interferometry .......................................... 27
1.17.1 Optical Flat as Comparator.......... 29
1.17.2 NPL Flatness Interferometer......... 30
1.18 Straightness ............................................ 30
1.19 Flatness .................................................. 31
1.20 Comparator.............................................. 31
1.20.1 Sigma Comparators..................... 32
1.20.2 Mikrokator .................................... 32
1.20.3 Pneumatic Comparators .............. 33
1.21 Surface Finish.......................................... 37
1.21.1 Lay and Flaw ................................ 37
1.21.2 Methods of Establishing Datum.... 38
1.21.3 Numerical Values to Represent
Surface Finish .............................. 39
1.21.4 Representation of Surface Finish.. 40
1.21.5 Talysurf......................................... 40
1.22 Screw Thread Metrology.......................... 40
1.23 Acceptance Tests.................................... 43
Practice Questions.................................. 47
2. Material Science
2.1 Metals ..................................................... 56
2.2 Non-metals ............................................. 56
2.3 Organic Polymer...................................... 56
2.4 Ceramics ................................................. 58
2.5 Crystal Structures of Ceramics................ 60
2.5.1 AX-Type Crystal Structures of
Ceramics...................................... 60
2.5.2 Cesium Chloride Structure........... 60
2.5.3 Zinc Blende Structure.................. 61
2.5.4 AmXP-Type Crystal Structures..... 61
2.5.5 AmBnXp-Type Crystal Structures...61
2.6 Composite Materials................................ 62
2.7 Phase Diagrams ...................................... 62
2.8 Experimental Methods of Constructing
Phase Diagrams ...................................... 68
2.8.1 Thermal Analysis Allotropy method..68
2.8.2 Metallographic Method................ 68
2.8.3 X-ray diffractionn Method ............ 68
2.9 Fe-Fe3C Phase Diagram ........................ 68
2.10 Development of Microstructure in Fe-C
System..................................................... 71
2.11 Family of Cast Irons................................. 72
2.12 Effect of Alloying Element on Iron ........... 73
2.13 Relationship between the Phase Diagrams
and Properties of Alloys........................... 74
2.14 High Strength Low Alloy steel (HSLA)..... 75
2.15 Defects in the Materials........................... 79
2.15.1 Point Defects ............................... 79
2.15.2 Surface Defects ........................... 80
2.15.3 Line Defects................................. 80
2.16 Yield Point Phenomenon.......................... 82
2.17 Strengthening Mechanism....................... 82
2.17.1 Alloying ........................................ 82
2.17.2 Grain Refinement......................... 82
2.17.3 Work (strain) Hardening .............. 83
2.18 Type of Bond ........................................... 85
2.19 Time Temperature Transformation (TTT)
Diagram................................................... 85
2.20 Heat Treatment ........................................ 89
2.20.1 Annealing..................................... 89
2.20.2 Normalizing.................................. 91
2.20.3 Hardening.................................... 91
2.20.4 Tempering.................................... 93
2.20.5 Case Hardening........................... 94
2.21 TTT Diagrams for Hypo and Hypereutectoid Steels....................................... 99
2.22 Crystal Systems....................................... 99
2.22.1 Simple Cubic Structure.............. 101
2.22.2 Body Centred Cubic (BCC)
Structure .................................... 101
2.22.3 Face Centred Cubic (FCC)
Structure .................................... 101
2.23 Hardenability Curves Jominy end Quench
Test ................................................... 102
2.24 Mechanism of Crystallization................. 102
2.25 Methods for Measurement of Grain Size .....103
2.26 Crystal Directions .................................. 103
2.27 Crystal Planes........................................ 104
2.28 Creep ................................................... 106
2.29 Tensile Test ............................................ 107
2.30 Hardness Tests...................................... 107
2.31 Impact Test ............................................ 107
2.32 Aluminum Alloys ................................... 108
2.32.1 Non Heat Treatable Al Alloys ..... 108
2.32.2 Heat Treatable Wrought Alloys .. 109
2.32.3 Al – base Casted Alloys............. 111
2.33 Brasses.................................................. 112
2.34 Bronzes.................................................. 113
2.34.1 Tin-bronzes ............................... 114
2.34.2 Tin Free Bronzes........................ 115
2.34.3 Si-Bronzes.................................. 115
2.34.4 Be-Bronzes ............................... 115
2.34.5 Leaded Bronzes ........................ 115
2.35 Introduction to Titanium Alloys .............. 116
2.36 Corrosion Definition ............................... 117
2.37 Copper .................................................. 127
2.38 Nano-materials ...................................... 130
Practice Questions................................ 137
3. Casting
3.1 Design of Risers .................................... 165
3.2 Riser Design for Steel Castings ............ 168
3.3 Gating System ....................................... 170
3.4 Green Sand Mould ................................ 175
3.5 Types of Solidification............................ 176
3.5.1 Skin Forming ............................. 176
3.5.2 Dandritic Growth........................ 176
3.5.3 Pouring Temperature ................. 177
3.6 Die Casting............................................ 177
3.7 Centrifugal Casting................................ 179
3.7.1 True Centrifugal Casting ............ 179
3.7.2 Semicentrifugal Casting ............ 180
3.7.3 Centrifuging ............................... 180
3.8 Slush Casting......................................... 181
3.9 Sodium Silicate (CO2) Moulding............ 181
3.10 Blow Moulding ...................................... 181
3.11 Shell Moulding....................................... 182
3.12 Investment Casting................................ 183
3.13 Types of Casting Defects ...................... 184
3.14 Types of Furnaces ................................. 184
3.15 Metallurgy of Cast Steel......................... 185
3.15.1 Composition .............................. 185
3.15.2 Melting of Cast Irons (Cupola)... 185
3.15.3 Steps in Operation..................... 186
3.16 Methods of Purifying Material................ 186
3.17 Continuous Casting ............................... 187
3.18 Injection Moulding ................................. 187
Practice Questions................................ 200
4. Metal Cutting
4.1 Terminology of Single Point Cutting Tool (As
per ASA)................................................ 213
4.1.1 Back Rake Angle ....................... 213
4.1.2 Side Cutting Edge Angle ........... 214
4.1.3 Side Rake Angle ........................ 215
4.1.4 Side Relief Angle ....................... 215
4.1.5 End Cutting Edge Angle............ 216
4.1.6 End Relief Angle (Clearance angle)...216
4.1.7 Nose Radius .............................. 216
4.1.8 ASA Tool Signature .................... 216
4.2 British System........................................ 217
4.3 Normal or Orthogonal Rake System (ORS).....217
4.4 Types of Metal Cutting Process............. 217
4.5 Distribution of Heat in Metal Cutting...... 218
4.6 Types of Chips....................................... 219
4.6.1 Continuous Chips ...................... 219
4.6.2 Discontinuous Chips.................. 219
4.6.3 Chips with Build up Edge .......... 219
4.6.4 Chips with Unusual Strains........ 220
4.7 Merchant’s Analysis for Chip Thickness
Ratio ................................................... 220
4.8 Determination of Cutting Forces............ 222
4.9 Determination of Area of Shear Plane and
Shear Strength....................................... 223
4.10 Assumptions of Merchant’s Circle ......... 224
4.11 Determination of Shear Angle ............... 225
4.12 Velocity Triangle..................................... 225
4.13 Ernest and Merchant Theory ................. 226
4.14 Lee and Shaffer (slip line field theory)... 227
4.15 Contact Length...................................... 238
4.16 Measurement of Temperature................ 238
4.16.1 Tool Workpiece Thermocouple .. 238
4.16.2 Inserted Thermocouple ............. 239
4.16.3 Infrared Measurement................ 239
4.16.4 Hardness and Microstructure ..........
Studies....................................... 239
4.17 Cutting Fluids......................................... 239
4.17.1 Properties of Cutting Fluids ....... 240
4.17.2 Selection of Cutting Fluids ........ 240
4.17.3 Workpiece Material.................... 240
4.18 Mechanism of Tool Wear ....................... 241
4.18.1 Types of Tool Wear..................... 243
4.18.2 Taylor’s Tool Life Equation.......... 244
4.19 Effect of Parameters on Tool Life........... 249
4.20 Machinability.......................................... 250
4.21 Economics of Machining ....................... 251
4.22 Tool Materials......................................... 257
4.23 Measurement of Cutting Forces ............ 259
4.24 Grinding................................................. 259
4.24.1 Classification of Grinding Processes..260
4.24.2 Structure .................................... 262
4.24.3 Grade......................................... 263
4.24.4 ISO Designation of Grinding Wheel ...263
4.24.5 Wheel Dressing.......................... 264
4.25 Unconventional/Non-traditional Machining
Processes.............................................. 264
4.25.1 Electro Chemical Machining...... 264
4.25.2 Electrode Discharge Machining 268
4.25.3 Ultrasonic Machining................. 270
4.25.4 Abrasive Jet Machining ............. 271
4.26 Drilling ................................................... 272
4.26.1 Drill Geometry............................ 273
4.26.2 Important Angles of a Drill ......... 275
4.26.3 Machining Time ........................ 276
4.27 Milling ................................................... 277
4.27.1 Peripheral or Slab Milling Operation...277
4.27.2 Face Milling................................ 277
4.27.3 End Milling ................................. 278
4.27.4 Gang Milling............................... 278
4.27.5 Straddle Milling.......................... 278
4.27.6 Up Milling and Down Milling...... 279
4.27.7 Mechanics of Milling.................. 279
4.27.8 Mean Chip Thickness ............... 280
4.28 Powder Metallurgy................................. 287
4.29 Jigs and Fixtures ................................... 289
4.29.1 Principle of Location .................. 290
4.29.2 Steps in Designing the Jigs....... 291
4.30 Screw Thread Manufacturing ................ 292
4.31 Gear Manufacturing............................... 293
4.31.1 Materials for Gears .................... 293
4.31.2 Forming...................................... 293
4.31.3 Machining .................................. 294
Practice Questions................................ 297
5. Metal Forming
5.1 Wire Drawing ......................................... 341
5.1.1 Defects of Wire Drawing............ 342
5.2 Tube Drawing ........................................ 342
5.3 Extrusion................................................ 343
5.3.1 Forward Extrusion or Direct .............
Extrusion .................................... 343
5.3.2 Backward Extrusion or Indirect ........
Extrusion .................................... 344
5.3.3 Hydrostatic Extrusion................. 345
5.3.4 Impact Extrusion........................ 346
5.4 Analysis of Wire Drawing and Extrusion 347
5.5 Extrusion Defects................................... 356
5.6 Forging .................................................. 356
5.6.1 Forging Defects ......................... 358
5.6.2 Analysis of Forging .................... 359
5.7 Rolling ................................................... 374
5.7.1 Mechanics of Rolling ................. 375
5.7.2 Camber Rolls ............................. 378
5.7.3 Back up Rolls............................. 378
5.7.4 Three High Mill........................... 379
5.7.5 Planetary Mill.............................. 380
5.7.6 Tandem Mill................................ 380
5.7.7 Rolling Defects........................... 380
5.7.8 Test to Calculate the Defects..... 381
5.8 Punching and Blanking ......................... 383
5.9 Deep Drawing........................................ 385
5.9.1 Redrawing.................................. 387
5.9.2 Analysis of Deep Drawing ......... 387
5.9.3 Measuring of Formability ........... 391
5.9.4 Common Defects in Deep Drawing...391
5.10 Bending ................................................. 392
Practice Questions................................ 399
6. Welding
6.1 Metallurgy in Welding............................ 414
6.2 Bead Geometry .................................... 416
6.3 Classification of Welding Process ......... 417
6.4 Arc Welding........................................... 417
6.4.1 Shielded Metal Arc Welding ............
(SMAW)...................................... 417
6.4.2 Transformer................................ 418
6.4.3 Submerged Arc Welding (SAW) 429
6.4.4 Gas Tungsten Arc Welding (GTAW) or .
Tungsten Inert Gas Welding (TIG)...430
6.4.5 Arc Blow..................................... 431
6.4.6 Duty Cycle ................................. 432
6.4.7 Plasma Arc Welding (PAW)........ 432
6.4.8 Electro Slag/Electro Gas Welding ...433
6.5 Resistance Welding............................... 434
6.5.1 Spot Welding ............................. 435
6.5.2 Projection Welding..................... 436
6.5.3 Seam Welding............................ 436
6.5.4 High Frequency Resistance ............
Welding (HFRW) ........................ 444
6.5.5 Flash Butt Welding..................... 445
6.6 Solid State Welding processes.............. 445
6.6.1 Friction Welding......................... 445
6.6.2 Ultrasonic Welding..................... 446
6.6.3 Explosive Welding ..................... 447
6.7 Radiant Energy Welding........................ 448
6.7.1 Electron Beam Welding ............. 448
6.7.2 Laser Beam Welding ................. 449
6.8 Thermit Welding Process....................... 450
6.9 Allied Processes................................... 451
6.10 Gas Welding.......................................... 452
6.11 Forces in Welding.................................. 455
6.12 Types of Metal Transfer.......................... 455
6.13 Types of Fluxes...................................... 456
6.14 ISO Designation..................................... 457
6.15 Welding Positions .................................. 458
6.16 Types of Joints....................................... 458
6.17 Types of Weld........................................ 459
6.18 Welding Symbols................................... 460
6.19 Defects in Welding ................................ 461
Practice Questions................................ 465