Introduction to the Physical Metallurgy of Welding deals primarily with the welding of steels, which reflects the larger volume of literature on this material; however, many of the principles discussed can also be applied to other alloys.
The book is divided into four chapters, in which the middle two deal with the microstructure and properties of the welded joint, such as the weld metal and the heat-affected zone. The first chapter is designed to provide a wider introduction to the many process variables of fusion welding, particularly those that may influence microstructure and properties, while the final chapter is concerned with cracking and fracture in welds. A comprehensive case study of the Alexander Kielland North Sea accommodation platform disaster is also discussed at the end.
The text is written for undergraduate or postgraduate courses in departments of metallurgy, materials science, or engineering materials. The book will also serve as a useful revision text for engineers concerned with welding problems in industry.
Inhalt
Preface to the 1st Edition
Preface to the 2nd Edition
Prologue
1. Fusion Welding - Process Variables
Fusion Welding
Principles of Consumable Development
Absorption of Gases in the Weld Metal
Nitrogen Absorption
Hydrogen Absorption
Composition of Welds
Summary of Process Variables
The Weld Thermal Cycle
Heat-Flow Equations
The Thermal Cycle of the Base Metal
Refinements to Rosenthal's Heat Flow Equation
Further Refinements to the Heat-Flow Equations
Heat Flow in Electroslag Welding
Weld Simulation
Summary of Weld Thermal Cycle Results
Residual Stresses in Welds
Stresses and Strains Generated by Changes in Temperature
Stresses Generated by the a Phase Transformation
Measurement of Residual Stresses in Welds
Numerical Methods of Estimating Residual Stresses in Welds
Summary of Residual Stress Work
References
Further Reading
2. The Weld Metal
Characteristics of Weld Solidification
Thermal Gradients and Turbulence in the Melt
Geometry of the Weld Melt
Epitaxial Solidification
Crystal Growth and Segregation
No Diffusion in Solid; Perfect Mixing in Liquid
No Diffusion in Solid; Diffusional Mixing in Liquid
Cellular and Dendritic Solidification in Welds
Dendritic Growth in Single Crystal Welds of Stainless Steel
Refining Weld Structures
Phase Transformations during Cooling of the Weld Metal
Kinetics of Phase Transformations
Transformations in Duplex Stainless Steel Welds
Transformations in Carbon and Low Alloy Steel Welds
Role of Slag Inclusions in Transformation Kinetics
Modeling the Microstructure and Properties of Weld Metals
Weld Metal Toughness
References
Further Reading
3. The Heat-Affected Zone
The Base Material
The Base Metal's Carbon Equivalent
The Heating Cycle
Recrystallization
The a Phase Transformation
Precipitate Stability
Precipitate Coarsening during a Weld Thermal Cycle
Precipitate Dissolution during a Weld Thermal Cycle
Grain Growth
Kinetics of Grain Growth
Grain Growth during Welding, Assuming Particle Dissolution
Grain Growth during Welding, Assuming Particle Coarsening
Practical Considerations of Grain Growth and Grain Growth Control in the HAZ
Reactions at the Fusion Line
Transformations during Cooling
Grain Growth Zone
Grain Refined Zone
Partially Transformed Zone
Zone of Spheroidized Carbides
Zone of 'Unchanged' Base Material
The Heat-Affected Zone Microstructure of Oxide-Dispersed Steels
Predicting the Microstructure and Properties of the HAZ
Weld Simulation
Hardness Measurements
Weld CCT Diagrams
Hardness Changes in Aluminum Alloy Welds
Weld Microstructure Diagrams
Grain Growth Diagrams
Multi-Run Welds
The Weld Metal
The HAZ
PC Software for Weldability Prediction
References
Further Reading
4. Cracking and Fracture in Welds
Fracture Toughness
Fracture Toughness Testing
Solidification Cracking
Solidification Structure
Segregation
Residual Stresses and Joint Geometry
Mechanism of Solidification Cracking
Liquation Cracking
Lamellar Tearing
Mechanism of Lamellar Tearing
Cold Cracking
Role of Hydrogen
Role of Stress
Role of Microstructure
Mechanism of Cold Cracking
Reheat Cracking
Effect of Reheating on the Microstructure of a 0.5 Cr-Mo-V Alloy
Mechanism of Reheat Cracking
Case Study: The Alexander Kielland Disaster
Construction of the Alexander Kielland
The Construction and Fitting of the Sonar Flange Plate
Capsize of the Alexander Kielland
Metallographic Examination of the Sonar Flange Plate Welds
Possible Effects of the Weld Thermal Cycle on the Bracing and Flange Plate Materials
Mechanism of Failure: Main Conclusions
References
Further Reading
Appendix: Weld Cracking Tests and Weldability Formula
Index