Dissimilar Metal Joining

Preface
About This Book
Contents
About the Author
1 Fundamentals of Dissimilar Metal Joining
1.1 Need
1.2 Types of Dissimilar Metal Joints
1.3 Issues in Dissimilar Metal Joining
1.4 Parent Metal Characteristics and Dissimilar Metal Joining
1.4.1 Physical Properties
1.4.2 Mechanical Properties
1.4.3 Chemical Composition
1.4.4 Dimension Characteristics
1.5 Approaches to Address Issues of Dissimilar Metal Joining
1.5.1 Selection of Appropriate Joining Technology
1.5.2 Using Transition/Tri-metallic Joint
1.5.3 Dilution
1.5.4 Electrode, Filler Metal and Interlayer
1.5.5 Buttering and Cladding
1.5.6 Thermal and Mechanical Treatment
1.6 Performance Parameters of Dissimilar Metal Joints
References
2 Fundamentals of Dissimilar Metal Joining by Arc and Resistance Welding Processes
2.1 Introduction
2.2 Asymmetric Weld
2.2.1 Segregation
2.2.2 Unmixed Zone Formation
2.2.3 Intermetallic Compound Formation
2.2.4 Hardening of HAZ
2.2.5 Softening and Weakening of HAZ
2.2.6 Unfavourable Metallurgical Transformation
2.3 Residual Stress and Distortion
2.4 Corrosion Behaviour
2.5 Fusion Welding Processes for Dissimilar Metal Joining
2.5.1 Gas Tungsten Arc Welding
2.5.2 Gas Metal Arc Welding
2.5.3 Shielded Metal Arc and Submerged Arc Welding
2.6 Resistance Spot Welding
2.7 Brazing and Braze Welding
References
3 Dissimilar Metal Joining by Laser Welding
3.1 Fundamental of Laser Welding
3.2 Common Issues in Laser Welding
3.2.1 Embrittlement
3.2.2 Porosity
3.2.3 Solidification Cracking
3.2.4 Weld Bead Sagging
3.2.5 Misalignment and Misfit
3.2.6 Lack of Penetration and Fusion
3.2.7 Asymmetric Weld
3.2.8 Residual Stresses
3.2.9 Undesirable Metallurgical Transformations
3.3 Weldability by Laser Welding
3.3.1 Section Thickness
3.3.2 Physical Properties of Parent Metal
3.3.3 Metallurgical and Chemical Properties of Parent Metals
3.4 Few Approaches for Joining of Specific Dissimilar Metal Combinations
3.4.1 Joining of Al with Other Metals
3.4.2 Joining of Cu with Other Metals
3.5 Few Advances on Laser Welding and Brazing
3.5.1 Laser Welding of Alloy Steel and Stainless Steel
3.5.2 Laser Welding of Stainless Steel and Copper
3.5.3 Laser Welding of Alloy Steel/Stainless Steel and Aluminium
3.5.4 Laser Brazing of Aluminium and Steel
3.5.5 Laser Welding of Copper and Aluminium
3.5.6 Laser Welding of Aluminium and Aluminium Matric Composite
References
4 Dissimilar Metal Joining by Solid-State Joining Technologies
4.1 Introduction
4.2 Mechanism(s) of Solid-State Joining Processes
4.2.1 Metallic Bonding
4.2.2 Diffusion
4.2.3 Localized Melting
4.2.4 Dynamic Recrystallization
4.2.5 Mechanical Interlocking
4.3 Prerequisites for Solid-State Joining
4.3.1 Metallic Intimacy
4.3.2 Overcoming the Energy Barrier
4.4 Solid-State Joining Processes
4.4.1 Friction Welding
4.4.2 Friction Stir Welding
4.4.3 FSW Joint Evaluation
4.4.4 Ultrasonic Welding
4.4.5 Impact Welding
4.4.6 Diffusion Bonding
References
5 Dissimilar Metal Joining Using A-GTAW and HW-GTAW
5.1 Introduction
5.2 Fundamentals of Activated Flux-GTAW
5.2.1 Methodology
5.2.2 Mechanisms in A-GTAW
5.3 Advantages and Limitations of A-GTAW
5.4 Parent Metals and A-GTAW
5.4.1 Physical Properties
5.4.2 Chemical Properties
5.4.3 Metallurgical Properties
5.4.4 Mechanical Properties
5.4.5 Dimensional Properties
5.5 Flux and A-GTAW
5.5.1 Factors Affecting the Role of Fluxes
5.5.2 Selection of Fluxes
5.5.3 Welding Parameters
5.5.4 Flux Coating Patterns
5.6 Approaches to Enhance Joint Efficiency
5.7 Comparison of A-GTAW and M-GTAW Weld Joints
5.7.1 Preheat and Post-weld Heating (Bead Tempering)
5.7.2 Weld Metal Composition
5.7.3 Microstructure
5.7.4 Mechanical Properties
5.7.5 Distortion
5.7.6 Economics
5.8 Characteristics of a Typical Ferrite-Martensite and Austenitic Steel Weld of A-GTAW
5.8.1 Metallurgical Characteristics
5.8.2 Mechanical Properties
5.9 Hot Wire Gas Tungsten Arc Welding
5.9.1 HW-GTAW Parameters and Weld Joints
References
6 Dissimilar Metal Joining Using Filler Wire Fed A-GTAW
6.1 Introduction
6.2 Filler Wire Fed A-GTAW and Other Variants
6.3 Principle
6.3.1 Weld Metal Composition Adjustment in A-GTAW of Dissimilar Metals
6.4 Choice of External Filler Wire
6.5 Weld Composition Homogeneity
6.6 Welding Parameters of Filler Wire Fed A-GTAW
6.7 Flux Coating Patterns for Symmetric Weld Bead Geometry
6.8 Filler Wire Fed A-GTAW and Mechanical Properties
6.9 A-TIG Welding with Wire Feed of Dissimilar P92 Steel-316L ASS
References
7 Dissimilar Metal Joining by A-TIG Welding Using Interlayers
7.1 Background
7.2 Selection of Interlayer Material
7.3 Weld Joint Development
7.4 Role of Interlayer Width on Weld Joint Characteristics
7.4.1 Finalization of Interlayer Size
7.5 Calculation of Dilution Levels
7.6 Metallography
7.7 Mechanical Properties
7.8 Stability of Retained Austenite
7.9 Effect on Carbon Migration
7.10 A-TIG Welding Using Interlayers to Develop Functionally Graded Materials
7.10.1 Development of FG Weld Joint
7.10.2 Optimization of Interlayer Size
7.10.3 Chemical Composition of FG Joint
7.10.4 Microstructure of FG Joint
7.10.5 Effect on Carbon Migration
7.10.6 Mechanical Properties of FG Joint
7.11 Summary
References
8 Dissimilar Metal Joining of Steel-Aluminium Alloy by Spot Welding
8.1 Background
8.2 Challenges in Joining of Steel-Aluminium by Spot Welding
8.2.1 Formation of Intermetallic Compound
8.2.2 Interface Cracking Due to Residual Tensile Stress
8.2.3 Discontinuities like Porosity in Weld, Indentation on Aluminium Sheet
8.2.4 Softening/Hardening of Heat-Affected Zone in Aluminium/Steel Sheets
8.2.5 Inclusion and Poor Bonding Due to Alumina Formation
8.3 Characteristics of Resistance Spot Weld Affecting Tensile/Shear Strength
8.3.1 Weld Nugget Diameter
8.3.2 Metallurgical Characteristics of Spot Weld Joint
8.3.3 Soundness of the Weld Joints
8.3.4 Electrode Indentation on the Aluminium Sheet
8.4 Resistance Spot Welding and Its Parameters
8.4.1 Steel-Aluminium Spot Welding
8.5 Failure Modes in Resistance Spot Weld Joints
8.6 Mechanism of Fracture of Spot Weld Joints
8.7 Approaches to Enhance Joint Efficiency
8.7.1 Cover Sheet Approach
8.7.2 Role of Interlayers in Steel-Aluminium Welding
8.8 Resistance Spot Welding of Galvanized Steel-Aluminium Alloy Sheets
8.9 Summary
References
9 Joining of Dissimilar Metals by Diffusion Bonding
9.1 Introduction
9.2 Mechanism of Bonding
9.3 Stages of Diffusion Bonding
9.4 Diffusion Bonding Conditions
9.4.1 Surface Roughness
9.4.2 Bonding Pressure
9.4.3 Bonding Temperature
9.4.4 Bonding Time
9.4.5 Vacuum
9.4.6 Metallurgical Aspects
9.5 Dissimilar Metal Bonding
9.5.1 Thermo-Physical Properties
9.5.2 Mechanical Properties
9.5.3 Metallurgical Aspects
9.6 Diffusion Brazing
9.6.1 Thermal Cycle for Diffusion Brazing
9.6.2 Brazing Time
9.6.3 Brazing Pressure
9.6.4 Metallurgy of Diffusion Brazing
9.6.5 Filler Metal for Diffusion Brazing
References
10 Dissimilar Metal Joining of Steel-Aluminium Alloy by Friction Stir Welding
10.1 Background
10.2 FSW Fundamentals
10.2.1 Heat Generation in FSW
10.3 Aluminium Steel Metal System
10.4 Al-Steel Butt Joint
10.4.1 Zones in Friction Stir Welded Joints of Al-Steel
10.5 Process Parameters Affecting Joining in Butt Joining
10.5.1 Tool Rotational Speed
10.5.2 Tool Traverse Speed
10.5.3 Tool Pin Offset
10.6 Al-Steel Lap Joint
10.6.1 Al-Steel Lap Seam Friction Stir Welding
10.6.2 Al-Steel Lap Spot Friction Stir Welding
10.7 Summary
References
11 Adhesive Joining of Dissimilar Metals
11.1 Introduction
11.2 Developing Good Adhesive Joint
11.3 Wetting in Adhesive Joining
11.4 Adhesive Joining Offers Multiple Advantages Over Metallic Joining
11.5 Limitations of Adhesive Joining
11.6 Adhesive and Joint Characteristics
11.6.1 Adhesive
11.6.2 Selection of Adhesive
11.7 Adhesive Joint Design
11.7.1 Common Type of Loading on Adhesive Joints
11.7.2 Overlap Length
11.7.3 Overlap Length and Stress Distribution in Adhesive Lap Joints
11.7.4 Common Design Joint Designs
11.8 Mechanisms Responsible for Mechanical Performance of Adhesive Joints
11.9 Parameter of Adhesive Joining
11.9.1 Surface Cleanliness
11.9.2 Surface Roughness
11.9.3 Type of Adhesive
11.9.4 Adhesive Bond Line Thickness
11.9.5 Curing Time and Temperature
11.10 Dissimilar Metal Joining
References
12 Residual Stress and Thermal Treatment of Dissimilar Metal Joints
12.1 Residual Stress
12.1.1 Effect of Residual Stress
12.1.2 Residual Stress in Similar and Dissimilar Metal Joint
12.2 Factors Affecting Residual Stress
12.2.1 Thermal Stress
12.2.2 Plastic Deformation
12.3 Thermal Stress and Metals
12.3.1 Thermal Stress in the Dissimilar Metal Weld
12.4 Residual Stress and Filler/Electrode
12.5 Residual Stress and Post Weld Heat Treatment
12.6 Residual Stress and Characteristics of Parent Metals
12.7 Residual Stress and Component Geometry
12.7.1 Plate Joining
12.7.2 Pipe Joining
12.8 Residual Stress and Performance of Dissimilar Metal Joint
12.9 Thermal Treatment in Dissimilar Metal Joining
12.9.1 Preheating
12.9.2 Preheat and Metal Strengthening Mechanism
12.9.3 Preheat and Thermal Cycle
12.10 Post-dissimilar Metal Joining Thermal Treatment
12.10.1 Obstacles in Thermal Treatment
12.11 Metallurgical Transformation(s) During Thermal Treatment
12.11.1 Physical Metallurgy of Ferrous Metals
12.11.2 Physical Metallurgy of Non-ferrous Metals
12.11.3 Mechanical Behaviour
12.11.4 Residual Stress
References
Index