This book describes and systemizes analytical and numerical solutions for a broad range of instantaneous and continuous, stationary and moving, concentrated and distributed, 1D, 2D and 3D heat sources in semi-infinite bodies, thick plane layers, thin plates and cylinders under various boundary conditions. The analytical solutions were mainly obtained by the superimposing principle for various parts of the proposed 1D, 2D and 3D heat sources and based on the assumption that only heat conduction plays a major role in the thermal analysis of welds. Other complex effects of heat transfer in weld phenomena are incorporated in the solutions by means of various geometrical and energetic parameters of the heat source. The book is divided into 13 chapters. Chapter 1 briefly reviews various welding processes and the energy characteristics of welding heat sources, while Chapter 2 covers the main thermophysical properties of the most commonly used alloys. Chapter 3 describes the physical fundamentals of heat conduction during welding, and Chapter 4 introduces several useful methods for solving the problem of heat conduction in welding. Chapters 5 and 6 focus on the derivation of analytical solutions for many types of heat sources in semi-infinite bodies, thick plane layers, thin plates and cylinders under various boundary conditions. The heat sources can be instantaneous or continuous, stationary or moving, concentrated or distributed (1D, 2D or 3D). In Chapter 7 the temperature field under programmed heat input (pulsed power sources and weaving sources) is analyzed. In turn, Chapters 8 and 9 cover the thermal cycle, melting and solidification of the base metal. Heating and melting of filler metal are considered in Chapter 10. Chapter 11 addresses the formulation and solution of inverse heat conduction problems using zero-, first- and second-order algorithms, while Chapter 12 focuses on applying the solutions developed here to the optimization of welding conditions. In addition, case studies confirm the usefulness and feasibility of the respective solutions. Lastly, Chapter 13 demonstrates the prediction of local microstructure and mechanical properties of welded joint metals, while taking into account their thermal cycle. The book is intended for all researches, welding engineers, mechanical design engineers, research engineers and postgraduate students who deal with problems such as microstructure modeling of welds, analysis of the mechanical properties of welded metals, weldability, residual stresses and distortions, optimization of welding and allied processes (prewelding heating, cladding, thermal cutting, additive technologies, etc.). It also offers a useful reference guide for software engineers who are interested in writing application software for simulating welding processes, microstructure modeling, residual stress analysis of welds, and for robotic-welding control systems.

The main purpose of this book is to provide a unified and systematic continuum approach to engineers and applied physicists working on models of deformable welding material. The key concept is to consider the welding material as an thennodynamic system. Significant achievements include thermodynamics, plasticity, fluid flow and numerical methods. Having chosen point of view, this work does not intend to reunite all the information on the welding thermomechanics. The attention is focused on the deformation of welding material and its coupling with thermal effects. Welding is the process where the interrelation of temperature and deformation appears throughout the influence of thermal field on material properties and modification of the extent of plastic zones. Thermal effects can be studied with coupled or uncoupled theories of thermomechanical response. A majority of welding problems can be satisfactorily studied within an uncoupled theory. In such an approach the temperature enters the stress-strain relation through the thennal dilatation and influences the material constants. The heat conduction equation and the relations governing the stress field are considered separately. In welding a material is either in solid or in solid and liquid states. The flow of metal and solidification phenomena make the welding process very complex. The automobile, aircraft, nuclear and ship industries are experiencing a rapidly-growing need for tools to handle welding problems. The effective solutions of complex problems in welding became possible in the last two decades, because of the vigorous development of numerical methods for thermal and mechanical analysis.

After introducing the concepts and characteristics of welding thermal processes and weld pool behaviors, this book addresses essential advances in welding analysis and processes with an emphasis on the latest modeling and simulation methods. It covers techniques and formulas for assessing welding thermal processes, finite difference and finite analysis methods for calculating thermal conduction, and numerical simulation of weld pool behaviors in metal-inert-gas/metal-active-gas arc welding, It also covers keyhole and weld pool dynamics in plasma arc welding and vision-based sensing of weld pool shape and geometry. It also provides case studies of fluid flow and heat transfer in tungsten-inert-gas arc welding.