Welding Handbook: Volume 1: Fundamentals of Welding

386 Pages·1976·40.932 MB·English

by  American Welding Society (auth.)

Welding Handbook
Seventh Edition, Volume 1
Fundamentals of Welding
Welding Handbook
Seventh Edition, Volume 1
Fundamentals of Welding
The Five Volumes of the
Welding Handbook, Seventh Edition
1 Fundamentals of Welding
2 Welding Processes-
Arc and Gas Welding and Cutting,
Brazing, and Soldering
3 Welding Processes-
Resistance and Solid State Welding
and Other Joining Processes
4 Engineering Applications -Materials
5 Engineering Applications -Design
Welding Handbook
Seventh Edition, Volume 1
Fundamentals of Welding
Macmillan Education
Library of Congress Number: 75-28707
International Standard Book Number: 0-87171-126-5
American Welding Society, 2501 N.W. 7th Street, Miami, FL 33125
ISBN 978-1-349-03075-0 ISBN 978-1-349-03073-6 (eBook)
DOI 10.1007/978-1-349-03073-6
© 1976 by American Welding Society.
Softcover reprint of the hardcover 7th edition 1976 978-0-333-19874-2
All rights reserved.
Note: By publication of this handbook, the American Welding Society does
not insure anyone utilizing this handbook against liability arising from the use
of such handbook. A publication of a handbook by the American Welding
Society does not carry with it the right to make, use, or sell patented items.
Each prospective user should make an independent investigation.
Contents
Welding Handbook Committee . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x
Foreword. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
Preface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiv
Chapter 1, Survey of Processes for Joining
and Cutting Materials ........................................... 1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Arc Welding ................................................ 3
Shielded Metal Arc Welding ................................ 3
Submerged Arc Welding .................................... 6
Gas Metal Arc and Flux Cored Arc Welding .................. 7
Gas Tungsten Arc Welding ................................. 10
Plasma Arc Welding ...................................... 11
Electroslag and Electrogas Welding .......................... 12
Resistance Welding ......................................... 14
Flash Welding .............................................. 16
Oxyfuel Gas Welding ........................................ 17
Solid State Welding ......................................... 18
Diffusion Welding ........................................ 18
Friction Welding ......................................... 19
Electron Beam Welding ...................................... 20
Laser Beam Welding ........................................ 21
Brazing. ................................................... 23
Soldering .................................................. 25
Adhesive Bonding .......................................... 26
Welding Plastics ............................................ 27
Thermal Cutting Processes ................................... 28
Oxygen Cutting ........................................... 28
Plasma Arc Cutting ....................................... 29
Air Carbon Arc Cutting ................................... 29
Laser Beam Cutting ....................................... 30
Supplementary Reading List .................................. 31
Chapter 2, Physics of Welding .................................... 33
Introduction ............................................... 34
Energy Sources for Welding .................................. 38
Electrical Sources of Welding Energy ........................ 38
v
CONTENTS
Chemical Sources of Welding Energy ........................ 41
Optical Sources of Welding Energy .......................... 44
Mechanical Sources of Welding Energy ...................... 48
Solid State Sources of Welding Energy ....................... 50
Arc Characteristics .......................................... 52
Definitions. .............................................. 52
The Plasma .............................................. 52
Temperature ............................................. 53
Radiation ................................................ 55
Electrical Features ........................................ 55
Influence of Magnetic Fields on Arcs ........................ 56
Metal Transfer ............................................. 59
Effect of Polarity on Metal Transfer in Argon ................ 60
Effect of Other Gases on Metal Transfer ..................... 63
Short Circuiting Transfer .................................. 64
Pulsed Current Consumable Electrode Transfer ............... 65
Submerged Arc Transfer ................................... 65
Covered Electrode Transfer ................................ 66
Melting Rates .............................................. 66
General Controlling Parameters ............................. 66
Melting Rates in GMAW .................................. 68
Melting Rates in SAW ..................................... 69
Melting Rates with SMA W ................................ 69
Physical Properties of Metals and Shielding Gases ............... 71
Thermal Conductivity ..................................... 73
Coefficient of Expansion ................................... 73
Ionization Potentials ...................................... 74
Thermionic Work Function ................................ 74
Metal Oxides ............................................. 74
Specific Heat. ............................................ 7 5
Supplementary Reading List .................................. 77
Chapter 3, Heat Flow in Welding .................................. 79
Introduction ............................................... 80
Peak Temperatures .......................................... 80
Peak Temperature Equation ................................ 80
Calculating Width of Heat-Affected Zone .................... 81
Cooling Rates .............................................. 84
Thick and Thin Plate Cooling Rate Equations ................ 84
Preheat Temperature and Critical Cooling Rate ............... 85
Solidification Rates ......................................... 88
Effect of Dendrite Spacing ................................ 88
Effect of Energy Input ..................................... 89
Typical Weld Thermal Cycles ................................. 90
Effects of Energy Input and Preheat Temperature .............. 90
vi
Contents
Effect of Plate Thickness and Weld Geometry ................. 95
Effect of Thermal Characteristics ............................ 96
Control of the Width of the Heat-Affected Zone .............. 97
Supplementary Reading List .................................. 98
Chapter 4, Welding Metallurgy .................................... 99
Introduction .............................................. 100
General Metallurgy ........................................ 100
Structure of Metals ....................................... 100
Phase Transformations ................................... 103
Effects of Deformation and Heat Treatment ................. 107
Review of Commercial Alloys ............................. 11 7
The Metallurgy of Welding .................................. 122
What Is a Weld? ......................................... 122
Weld Metal ............................................. 123
The Heat-Affected Zone .................................. 131
Base Metal. ............................................. 13 7
Summary ............................................... 142
Weldability Testing ........................................ 143
Theoretical Tests ........................................ 143
Simulated Tests .......................................... 143
Actual Welding Tests ..................................... 145
Brazing and Soldering Metallurgy ............................ 149
Supplementary Reading List ................................. 151
Chapter 5, Testing for Evaluation of Welded Joints .................. 153
Introduction .............................................. 154
Tensile Properties-Strength and Ductility ..................... 155
Tension Tests ........................................... 155
Hardness Tests .......................................... 163
Constant Load Rupture Tests .............................. 166
Bend Tests .............................................. 166
Fracture Toughness ........................................ 170
Concepts Relating to Fracture Toughness .................... 171
Linear Elastic Fracture Mechanics ......................... 174
Engineering Procedures for Elastic-
Plastic Toughness ...................................... 179
Special Problems of Welded Joints ........................ 183
Fatigue Properties of Welded Structural Joints ................. 186
Description of Phenomenon ............................... 186
Measurement of Fatigue Properties ......................... 189
Test Specimens .......................................... 190
Fatigue Strength of Welded Joints .......................... 191
Summary of Fatigue Data ................................. 198
Improvement Techniques ................................. 200
vii
CONTENTS
Corrosion Fatigue ....................................... 200
Thermal Fatigue ......................................... 200
Corrosion Factors Affecting the Testing and
Performance of Welded Joints ........................... 201
Types of Corrosion ...................................... 201
Corrosion Testing of Welded Joints ........................ 204
Evaluation of Corroded Weldments ........................ 206
Elevated Temperature Behavior .............................. 207
Creep-Rupture Phenomena ................................ 207
Test Method ............................................ 207
Method of Reporting and Extrapolating ..................... 208
Significance of Weld Discontinuities .......................... 209
Types of Weld Discontinuities ............................. 209
Effect of Discontinuities on the Performance
of Welded Joints ...................................... 212
Code Standards .......................................... 215
Reference List. ............................................ 21 7
Supplementary Reading List. ................................ 219
Chapter 6, Residual Stresses and Distortion ........................ 221
Introduction .............................................. 222
Causes of Residual StresSes .................................. 224
Macroscopic and Microscopic Residual Stresses .............. 224
Formation of Residual Stresses ............................ 225
Thermal Stresses during Welding and
Resulting Residual Stresses .............................. 229
Residual Stresses and Reaction Stresses
in Weldments ......................................... 230
Effects of Residual Stresses .................................. 231
Fracture under Tensile Stresses ............................ 231
Buckling under Compressive Loading ....................... 234
Fatigue Fracture ......................................... 236
Effects of Environment ................................... 23 7
Measurement of Residual Stresses in Weldments. ............... 238
Classification of Techniques for Measuring
Residual Stresses ...................................... 238
Measurement of Residual Stresses by
Stress-Relaxation Techniques ............................ 239
Measurement of Residual Stresses by
X-ray Diffraction Techniques ............................ 243
Typical Residual Stresses in Weldments ....................... 244
Distribution of Residual Stresses in
Typical Welds ......................................... 244
Various Factors Affecting Residual Stresses
in Welds ............................................. 244
viii
Contents
Weld Distortion ........................................... 248
Fundamental Types of Distortion .......................... 248
Transverse Shrinkage of Butt Welds ........................ 250
Transverse Shrinkage of Fillet Welds ....................... 255
Longitudinal Shrinkage of Butt Welds ...................... 255
Longitudinal Shrinkage of Fillet Welds ..................... 256
Angular Change of Butt Welds ............................ 256
Distortion Caused by Angular Changes
of Fillet Welds ........................................ 258
Bending Distortions Induced by
Longitudinal Shrinkage ................................. 260
Buckling Distortion ...................................... 261
Solution of Practical Problems. ............................ 261
Design and Procedures for Reducing Residual
Stresses and Distortion ................................. 265
Reduction of Residual Stresses ............................. 265
Control of Distortion .................................... 265
Correction of Distortion .................................. 267
Thermal and Mechanical Treatments of
Weldments ........................................... 268
Reasons for Thermal and Mechanical
Treatments of Weldments ............................... 268
Common Thermal Treatments for Weldments ............... 269
Peening ................................................ 273
Proofstressing ........................................... 274
Vibratory Stress Relief ................................... 274
Reference List. ............................................ 276
Supplementary Reading List ................................. 278
Appendix A, Terms and Definitions ............................... 279
Appendix B, Metric Practice Guide ............................... 337
Index ......................................................... 361
ix