Principles of Welding Processes, Physics, Chemistry, and Metallurgy

by Messler, Robert W.

• ISBN13: 9780471253761
• ISBN10: 0471253766
• Edition: 1st
• Format: Hardcover
• Copyright: 1999-05-04
• Publisher: Wiley-VCH

Summary

Principles of Welding departs from existing books with its clear, unambiguous presentation, which is easily grasped even by undergraduate students, yet given at the advanced level required by experienced engineers.

Author Biography

ROBERT W. MESSLER, JR., PhD, FASM, FAWS, is Associate Professor and Director of the Warren F. Savage Materials Joining Laboratory at Rensselaer Polytechnic Institute in Troy, New York. With over three decades in diverse areas of advanced materials and processes in industry and academia, Professor Messler has published numerous papers on welding, brazing, soldering, and innovative integral fastening as well as the book Joining of Advanced Materials. 18 02 An advanced yet accessible treatment of the welding process and its underlying science. <p>Despite the critically important role welding plays in nearly every type of human endeavor, most books on this process either focus on basic technical issues and leave the science out, or vice versa. <I>In Principles of Welding</I>, industry expert and prolific technical speaker Robert W. Messler, Jr. takes an integrated approach&mdash;presenting a comprehensive, self-contained treatment of the welding process along with the underlying physics, chemistry, and metallurgy of weld formation. <p>Promising to become the standard text and reference in the field, this book provides an unprecedented broad coverage of the underlying physics and the mechanics of solidification&mdash;including peritectic and eutectic reactions&mdash;and emphasizes material continuity and bonding as a way to create a joint between materials of the same general class. The author supplements the book with hundreds of tables and illustrations, and correlates the science to welding practices in the real world. <p><I>Principles of Welding</I> departs from existing books with its clear, unambiguous presentation, which is easily grasped even by undergraduate students, yet given at the advanced level required by experienced engineers.

Table of Contents

Preface	xix
I THE PROCESS AND PROCESSES OF WELDING
Introduction to the Process of Welding	3	(14)
What Is Welding?	3	(3)
The Evolution of Welding as a Process	6	(1)
The Nature of an Ideal Weld: Achieving Continuity	7	(3)
Impediments to Making Ideal Welds in the Real World	10	(2)
What It Takes to Make a Real Weld	12	(2)
Advantages and Disadvantages of Welding	14	(1)
Summary	15	(2)
References and Suggested Reading	15	(2)
Classifying Welding Processes	17	(23)
Why Classify Processes?	17	(1)
Mechanisms for Obtaining Material Continuity	18	(3)
The Roles of Temperature and Pressure	21	(2)
Alternative Bases for Classification	23	(12)
Fusion Versus Nonfusion	23	(2)
Pressure Versus Nonpressure	25	(1)
Energy Source for Welding	25	(2)
Interface Relationships and Classification by Energy Transfer Processes	27	(1)
Other Bases for Classification and Subclassification	28	(7)
Allied Processes	35	(2)
The AWS Classification Scheme	37	(2)
Summary	39	(1)
References and Suggested Reading	39	(1)
Fusion Welding Processes	40	(54)
General Description of Fusion Welding Processes	40	(1)
Chemical Fusion Welding Processes	41	(8)
Oxyfuel Gas Welding	41	(5)
Aluminothermic Welding	46	(3)
Electric Arc Welding Processes	49	(22)
Nonconsumable Electrode Arc Welding Processes	50	(1)
Gas-Tungsten Arc Welding	51	(4)
Plasma Arc Welding	55	(2)
Magnetically Impelled Arc Butt Welding	57	(3)
Consumable Electrode Arc Welding Processes	60	(1)
Gas-Metal Arc Welding	60	(4)
Shielded-Mental Arc Welding	64	(2)
Flux-Cored Arc Welding	66	(2)
Submerged Arc Welding	68	(1)
Electrogas Welding	69	(1)
Electroslag Welding	70	(1)
Resistance Welding Processes	71	(6)
Resistance Spot, Resistance Seam, and Projection Welding	71	(3)
Flash, Upset, and Percussion Welding	74	(3)
High-Intensity Radiant Energy or High-Density Beam Welding Processes	77	(15)
High-Energy-Density (Laser and Electron) Beam Welding Processes	80	(6)
Focused IR and Imaged Arc Welding	86	(2)
Microwave Welding	88	(4)
Summary	92	(2)
References and Suggested Reading	93	(1)
Nonfusion Welding Processes	94	(33)
General Description of Nonfusion Welding Processes	94	(3)
Pressure (Nonfusion) Welding Processes	97	(8)
Cold Welding Processes	98	(1)
Hot Pressure Welding	99	(1)
Pressure Gas Welding	100	(1)
Forge Welding	101	(1)
Roll Welding	102	(1)
Explosion Welding	103	(2)
Friction Welding Processes	105	(8)
Radial and Orbital Welding	107	(1)
Direct-Drive Versus Inertia-Drive (Friction) Welding	107	(1)
Angular and Linear Reciprocating (Friction) Welding	108	(1)
Ultrasonic (Friction) Welding	109	(3)
Friction Stir Welding	112	(1)
Friction Surfacing	113	(1)
Diffusion Joining Processes	113	(7)
Diffusion Welding	114	(4)
Conventional Diffusion Welding	118	(1)
Deformation Diffusion Welding	118	(1)
Resistance Diffusion Welding	118	(1)
Continuous Seam Diffusion Welding	118	(1)
Diffusion Brazing	119	(1)
Combined Forming and Diffusion Welding	119	(1)
Solid-State Deposition Welding Processes	120	(1)
Inspection and Repair of Nonfusion Welds	120	(3)
Summary	123	(4)
References and Suggested Reading	123	(4)
II THE PHYSICS OF WELDING
Energy for Welding	127	(20)
Introduction to the Physics of Welding	127	(1)
Sources of Energy for Welding	127	(1)
Source Energy, Transferred Power, Energy Density, and Energy Distribution	128	(4)
Energy Available at a Source (Energy Level or Capacity	128	(2)
Transferred Power	130	(1)
Source Intensity or Energy Density	130	(1)
Energy Distribution	131	(1)
Energy Input to a Weld	132	(2)
Causes of Loss During Energy Transfer From Source to Work	134	(1)
Transfer Efficiency of Processes	134	(4)
Effects of Deposited Energy: Good and Bad	138	(4)
Desirable Melting, Fluxing, or Softening	139	(2)
Adverse Effects of Heat in and Around the Weld	141	(1)
Effects of Energy Density and Distribution	142	(2)
Summary	144	(3)
References and Suggested Reading	146	(1)
The Flow of Heat in Welds	147	(34)
General Description of the Flow of Heat in Welds	147	(1)
Weld Joint Configurations	148	(6)
Types of Weld Joints	148	(4)
General Weld Design Guidelines	152	(2)
Size of a Weld and Amount of Welding	154	(1)
The Welding Thermal Cycle	154	(4)
The Generalized Equation of Heat Flow	158	(3)
Analysis of Heat Flow During Welding	161	(7)
Rosenthal's Simplified Approach	162	(3)
Modifications to Rosenthal's Solutions	165	(2)
Dimensionless Weld Depth Versus Dimensionless Operating Parameter	167	(1)
Effect of Welding Parameters on Heat Distribution	168	(4)
Prediction of Weld Zones and Weld Cooling Rates	172	(4)
Zones in Fusion-Welded Materials	172	(1)
Simplified Equations for Approximating Welding Conditions	173	(1)
Peak Temperatures	174	(1)
Width of the Heat-Affected Zone	174	(1)
Solidification Rate	174	(1)
Cooling Rates	175	(1)
Weld Simulation and Simulators	176	(2)
Summary	178	(3)
References and Suggested Reading	178	(3)
Thermally Induced Distortion and Residual Stresses During Welding	181	(35)
Origin of Thermal Stresses	181	(2)
Distortion Versus Residual Stresses	183	(8)
Causes of Residual Stresses in Weldments	185	(1)
Residual Stresses From Mismatch	186	(3)
Residual Stresses From Nonuniform, Nonelastic Strains	189	(1)
Causes of Distortion in Weldments	190	(1)
Typical Residual Stresses in Weldments	191	(3)
Effects of Distortion	194	(2)
Effects of Residual Stresses	196	(1)
Measurement of Residual Stresses in Weldments	197	(9)
Stress-Relaxation Techniques	199	(1)
A Sectioning Technique Using Electric-Resistance Strain Gauges	199	(2)
The Rosenthal-Norton Section Technique	201	(1)
The Mathar-Soete Hole Drilling Technique	202	(1)
The Gunnert Drilling Technique	202	(2)
The X-ray Diffraction Technique	204	(2)
Residual Stress Reduction and Distortion Control	206	(4)
The Interplay Between Residual Stresses and Distortion	206	(1)
Prevention Versus Remediation	206	(1)
Controlling or Removing Residual Stresses	207	(1)
Controlling or Removing Distortion	208	(2)
Numerical Methods for Estimating Residual Stresses	210	(1)
Summary	211	(5)
References and Suggested Reading	214	(2)
The Physics of Welding Energy or Power Sources	216	(54)
Electricity for Welding	216	(7)
The Physics of an Electric Arc and Arc Welding	223	(11)
The Physics of an Electric Arc	223	(1)
The Welding Arc	224	(1)
The Arc Plasma	224	(1)
Arc Temperature	224	(2)
Arc Radiation	226	(1)
Arc Electrical Features	226	(2)
Effect of Magnetic Fields on Arcs	228	(3)
Volt-Ampere Characteristics for Welding	231	(1)
Constant-Current Power Sources	232	(1)
Constant-Voltage Power Sources	232	(2)
Combined Characteristic Sources	234	(1)
The Physics of a Plasma	234	(3)
The Physics of Resistance (or Joule) Heating and Resistance Welding	237	(6)
Joule Heating	237	(2)
The Resistance Welding Cycle	239	(1)
Resistance Welding Power Supplies	239	(4)
The Physics of Electron Beams	243	(13)
Electron-Beam Generation	245	(3)
Electron-Beam Control	248	(4)
Role of Vacuum in EB Welding	252	(1)
Electron-Beam-Material Interactions	253	(3)
The Physics of Laser Beams	256	(9)
Laser Light	256	(1)
Laser Generation	256	(2)
Nd: YAG Lasers	258	(1)
CO2 Lasers	259	(1)
Laser-Beam Control	259	(1)
Laser-Beam-Material Interactions	260	(3)
Benefits of Laser-Beam and Electron-Beam Welding	263	(2)
The Physics of a Combustion Flame	265	(1)
Fuel Gas Combustion or Heat of Combustion	265	(1)
Flame Temperature	265	(1)
Flame Propagation Rate or Combustion Velocity	266	(1)
Combustion Intensity	266	(1)
The Physics of Converting Mechanical Work to Heat	266	(2)
Summary	268	(2)
References and Suggested Reading	269	(1)
Molten Metal Transfer in Consumable Electrode Arc Welding	270	(21)
Forces Contributing to Molten Metal Transfer in Welding	270	(4)
Gas Pressure Generation at Flux-Coated or Flux-Cored Electrode Tips	271	(1)
Electrostatic Attraction	272	(1)
Gravity	272	(1)
Electromagnetic Pinch Effect	272	(1)
Explosive Evaporation	272	(1)
Electromagnetic Pressure	273	(1)
Plasma Friction	273	(1)
Surface Tension	273	(1)
Free-Flight Transfer Modes	274	(4)
Globular Transfer	275	(1)
Spray Transfer	276	(2)
Bridging of Short-Circuiting Transfer Modes	278	(1)
Pulsed-Arc or Pulsed-Current Transfer	279	(1)
Slag-Protected Transfer	280	(1)
Variations of Major Transfer Modes	281	(1)
Effect of Welding Process Parameters and Shielding Gas on Transfer Mode	282	(7)
Effects on Transition Current	282	(3)
Shielding Gas Effects	285	(2)
Process Effects	287	(1)
Operating Mode or Polarity Effects	288	(1)
Summary	289	(2)
References and Suggested Reading	289	(2)
Weld Pool Convection, Oscillation, and Evaporation	291	(24)
Origin of Convection	291	(7)
Generalities on Convection in Weld Pools	292	(2)
Buoyancy or Gravity Force	294	(1)
Surface Gradient Force or Marangoni Convection	295	(1)
Electromotive Force or Lorentz Force	296	(1)
Impinging or Friction Force	297	(1)
Modeling Convection and Combined Force Effects	298	(1)
Effects of Convection	298	(7)
Effect of Convection on Penetration	300	(1)
Effect of Convection on Macrosegregation	301	(3)
Effect of Convection of Porosity	304	(1)
Enhancing Convection	305	(1)
Weld Pool Oscillation	306	(1)
Weld Pool Evaporation and Its Effects	307	(3)
Summary	310	(5)
References and Suggested Reading	310	(5)
III THE CHEMISTRY OF WELDING
Molten Metal and Weld Pool Reactions	315	(44)
Gas-Metal Reactions	316	(17)
Gas Dissolution and Solubility in Molten Metal	317	(6)
Solid Solution Hardening and Phase Stabilization	323	(3)
Porosity Formation	326	(1)
Embrittlement Reactions	327	(1)
Hydrogen Effects	328	(1)
Hydrogen Embrittlement	329	(2)
Hydrogen Porosity	331	(1)
Hydrogen Cracking	332	(1)
Molten Metal Shielding	333	(4)
Shielding Gases	333	(2)
Slags	335	(1)
Vacuum	335	(1)
Self-Protection and Self-Fluxing Action	336	(1)
Slag-Metal Reactions	337	(17)
Deoxidizing/Denitriding (or Killing) Versus Protection	337	(2)
Flux-Protected Welding Processes	339	(1)
Shielding Capacities of Different Processes	340	(1)
Slag Formation	341	(1)
Slag-Metal Chemical Reactions	342	(1)
Flux Types	342	(2)
Common Covered- and Cored-Electrode Flux Systems	344	(1)
Shielded Metal Arc Welding Electrode Coatings	344	(1)
Flux-Cored Arc Welding Fluxes	344	(1)
Submerged Arc Welding Fluxes	344	(1)
Basicity Index	344	(4)
Thermodynamic Model for Welding Slag-Metal Reactions	348	(6)
Summary	354	(5)
References and Suggested Reading	356	(3)
Weld Chemical Heterogeneity	359	(16)
Weld (Pool) Dilution	360	(3)
Microsegregation and Banding in the Weld Metal	363	(2)
Unmixed and Partially Mixed Zones	365	(1)
Impurities in the Weld Metal	366	(2)
Macrosegregation in Dissimilar Welds	368	(2)
Summary	370	(5)
References and Suggested Reading	370	(5)
IV THE METALLURGY OF WELDING
Weld Fusion Zone Solidification	375	(79)
Equilibrium Versus Nonequilibrium	378	(3)
Solidification of a Pure Crystalline Material	381	(21)
Criteria for Equilibrium at TE and Constant Pressure	381	(1)
Pure Material Growth Modes	382	(2)
Homogeneous Versus Heterogeneous Nucleation	384	(1)
Homogeneous Nucleation	384	(4)
Super- or Undercooling	388	(1)
Effect of Radius of Curvature on Supercooling	388	(1)
Heterogeneous Nucleation	389	(3)
Epitaxial and Competitive Growth	392	(3)
Effect of Weld Pool Shape on Structure	395	(4)
Competing Rates of Melting and Solidification	399	(3)
Effect of Nonequilibrium on Pure Material Solidification	402	(1)
Equilibrium Solidification of an Alloy	402	(4)
Prerequisites for the Solidification of Alloys	403	(1)
Equilibrium Solidification of a Hypothetical Binary Alloy (Case 1)	403	(3)
Nonequilibrium Solidification of Alloys	406	(17)
Boundary Conditions for Solidification of Alloys	406	(1)
Equilibrium Maintained Throughout the System at all Times: Microscopic Equilibrium (Case 1)	407	(1)
Complete Liquid Mixing/No Diffusion in the Solid (Case 2)	408	(2)
Expression for the Composition of Solid at the Advancing Solid-Liquid Interface	410	(1)
Calculation of the Average Composition of the Solid for Case 2	411	(2)
No Liquid Mixing/No Diffusion in the Solid (Case 3)	413	(7)
Trace of Average Composition in the Solid for Case 3	420	(1)
Expression for the Initial Transient in the Composition of the Solid Formed	420	(1)
Some Limitations of the Classic Models	421	(1)
Other Effects of Rapid Solidification	422	(1)
Nonequilibrium Solute Partitioning	422	(1)
Nonequilibrium Phases	422	(1)
Consequences of Nonequilibrium Solidification	423	(20)
Interdendritic Microsegregation	423	(2)
Solidus Suppression	425	(1)
Substructure Formation	426	(1)
Constitutional Supercooling	426	(4)
Effect of Cooling Rate on Substructure	430	(2)
Interface Stability	432	(6)
Nucleation of New Grains Within the Fusion Zone	438	(1)
Controlling Substructure	438	(5)
Centerline Segregation	443	(1)
Fusion Zone Hot Cracking	443	(6)
Mechanism of Hot Cracking	444	(3)
Remediation of Hot Cracking	447	(1)
Control of Weld Metal Composition	447	(1)
Control of Solidification Structure	448	(1)
Use of Favorable Welding Conditions	448	(1)
Summary	449	(5)
References and Suggested Reading	450	(4)
Eutectic, Peritectic, and Postsolidification Fusion Zone Transformations	454	(47)
Eutectic Reactions or Solidification of Two-Phase Alloys	455	(7)
Solidification at the Eutectic Composition	455	(5)
Solidification of Two-Phase Alloys at Noneutectic Compositions	460	(2)
Morphology of Eutectic Phases	462	(1)
Peritectic Reactions	462	(10)
Equilibrium Conditions (Case 1)	463	(1)
Alloys Below the Solubility Limit of the Solid Phase in the Peritectic	463	(3)
Alloys Between the Solubility Limit and the Peritectic Composition	466	(1)
Alloys With the Peritectic Composition	467	(1)
Alloys Beyond the Peritectic Composition, but Within the L + S Range	468	(1)
Alloys Past the L + S Range of a Peritectic in the Liquid Field	469	(1)
Nonequilibrium Conditions	469	(1)
No Diffusion in the Solid/Complete Mixing in the Liquid (Case 2)	470	(2)
No Diffusion in the Solid/No Mixing, Only Diffusion in the Liquid (Case 3)	472	(1)
Transformations in Ferrite + Austenite or Duplex Stainless Steels	472	(8)
Kinetics of Solid-State Phase Transformations: Nonequilibrium Versus Equilibrium	480	(9)
Austenite Decomposition Transformations	489	(9)
Equilibrium Decomposition to Ferrite + Pearlite (The Eutectiod Reaction)	491	(2)
Nonequilibrium Decomposition to Other Ferrite Morphologies (Very Slow to Moderately Slow Cooling Rates)	493	(1)
Nonequilibrium Transformation to Bainite (Faster Cooler Rates)	494	(1)
Nonequilibrium Transformation to Martensite (Very Fast Cooling Rates)	495	(3)
Sigma and Chi Phase Formation	498	(1)
Grain Boundary Migration	499	(1)
Summary	499	(2)
References and Suggested Reading	499	(2)
The Partially Melted Zone	501	(13)
Origin and Location of the Partially Melted Zone	501	(4)
Constitutional Liquation	505	(3)
Defects Arising in the PMZ	508	(3)
Conventional Hot Cracking and Liquation Cracking in the PMZ	508	(1)
Loss of Ductility in the PMZ	509	(1)
Hydrogen-Induced Cracking in the PMZ	510	(1)
Remediation of Defects in the PMZ	511	(1)
Summary	512	(2)
References and Suggested Reading	513	(1)
The Weld Heat-Affected Zone	514	(63)
Heat-Affected Zones in Welds	514	(1)
The HAZ in Work-Hardened or Cold-Worked Metals and Alloys	515	(11)
The Physical Metallurgy of Cold Work/Recovery/Recrystallization/Grain Growth	515	(5)
Cold Worked Metals and Alloys in Engineering	520	(3)
Avoiding or Recovering Property Losses in Work-Hardened Metals or Alloys	523	(2)
Development of a Worked Zone in Pressure-Welded Materials	525	(1)
The HAZ in a Solid-Solution-Strengthened Metal or of an Alloy	526	(3)
The Physical Metallurgy of Solid-Solution Strengthening or Alloying	526	(3)
Major Engineering Alloys Consisting of Single-Phase Solid Solutions	529	(1)
Maintaining Properties in Single-Phase Solid-Solution-Strengthened Alloys	529	(1)
The HAZ in Precipitation-Hardened or Age-Hardenable Alloys	529	(14)
The Physical Metallurgy of Precipitation- or Age-Hardenable Alloys	529	(7)
Important Precipitation-Hardenable Alloys in Engineering	536	(1)
Avoiding or Recovering Property Losses in Age-Hardenable Alloys	536	(7)
The HAZ in Transformation-Hardenable Alloys	543	(7)
The Physical Metallurgy of Transformation-Hardenable Alloys	543	(2)
Some Important Engineering Alloys Exhibiting Transformation Hardening	545	(1)
Welding Behavior of Carbon and Alloy Steels	545	(1)
Behavior of Carbon Steels	545	(2)
Behavior of Alloy Steels	547	(3)
The HAZ in Corrosion-Resistant Stainless Steels	550	(14)
The Physical Metallurgy of Stainless Steels	550	(3)
Major Stainless Steels Used in Engineering	553	(1)
Sensitization of Austenitic Stainless Steels by Welding	553	(8)
Welding of Ferritic and Martensitic Stainless Steels	561	(3)
The HAZ in Dispersion-Strengthened or Reinforced Alloys	564	(2)
HAZ Defects and Their Remediation	566	(8)
Liquation Cracking	567	(3)
Reheat or Strain-Age Cracking	570	(1)
Quench Cracking and Hydrogen Cold Cracking	571	(1)
Weld Decay, Knife-Line Attack, and Stress Corrosion Cracking	571	(2)
Lamellar Tearing	573	(1)
Summary	574	(3)
References and Suggested Reading	574	(3)
Weldability and Weld Testing	577	(48)
Weldability Testing	578	(1)
Direct Weldability or Actual Welding Tests	578	(28)
Fusion and Partially Melted Zone Hot-Cracking Tests	580	(2)
Finger Test	582	(1)
Houldcroft and Battelle Hot-Crack Susceptibility Tests	582	(1)
Lehigh Restraint Test	583	(1)
Variable-Restraint (or Varestraint) Test	583	(1)
Murex Hot-Cracking Test	584	(1)
Root-Pass Crack Test	584	(1)
Keyhole-Slotted-Plate Test	585	(1)
Navy Circular-Fillet-Weldability (NCFW) Test	586	(1)
Circular-Groove Cracking and Segmented-Groove Tests	586	(2)
Circular-Patch Test	588	(1)
Restrained-Patch Test	588	(1)
Sigmajig Test	588	(1)
Heat-Affected Zone General Cold-Cracking Weldability Tests	589	(3)
Hydrogen Cracking Testing	592	(3)
Implant Test	595	(1)
RPI Augmented Strain Cracking Test	596	(1)
Controlled-Thermal-Severity (CTS) Test	596	(2)
Lehigh Slot Weldability Test	598	(1)
Wedge Test	598	(1)
Tekken Test	598	(1)
Gapped-Bead-on-Plate or G-BOP Test	598	(3)
Reheat or Strain-Age Cracking Test	601	(1)
Compact Tension Test	601	(1)
Vinckier Test	601	(2)
Spiral Notch Test	603	(1)
Lamellar Tearing Tests	603	(1)
Lehigh Cantilever Lamellar Tearing Test	603	(1)
Tensile Lamellar Tearing Test	604	(2)
Indirect Weldability Tests or Tests of Simulated Welds	606	(1)
Weld Pool Shape Tests	606	(1)
Weld Testing	607	(14)
Transverse- and Longitudinal-Weld Tensile Tests	608	(1)
All-Weld-Metal Tensile Tests	609	(1)
Bend Ductility Tests	609	(1)
Impact Tests	610	(1)
Other Mechanical Tests	610	(5)
Corrosion Tests	615	(1)
General Corrosion and Its Testing	615	(2)
Crevice Corrosion and Its Testing	617	(1)
Pitting Corrosion and Its Testing	617	(1)
Intergranular Corrosion and Its Testing	617	(4)
Stress Corrosion and Its Testing	621	(1)
Summary	621	(4)
References and Suggested Reading	622	(3)
Closing Thoughts	625	(2)
Appendices	627	(12)
Index	639