Contains the papers presented at the fourth International Seminar "Numerical Analysis of Weldability" held in September 1997 at Schloss Seggau near Graz, Austria.

Contains the papers presented at the fourth International Seminar "Numerical Analysis of Weldability" held in September 1997 at Schloss Seggau near Graz, Austria.

This is the fourth volume in the well-established series of compendiums devoted to the subject of weld hot cracking. It contains the papers presented at the 4th International Cracking Workshop held in Berlin in April 2014. In the context of this workshop, the term “cracking” refers to hot cracking in the classical and previous sense, but also to cold cracking, stress-corrosion cracking and elevated temp. solid-state cracking. A variety of different cracking subjects are discussed, including test standards, crack prediction, weldability determination, crack mitigation, stress states, numerical modelling, and cracking mechanisms. Likewise, many different alloys were investigated such as aluminum alloys, copper-aluminum dissimilar metal, austenitic stainless steel, nickel base alloys, duplex stainless steel, creep resistant steel, and high strength steel.

Although the avoidance of hot cracking still represents a major topic in modern fabrication welding components, the phenomena have not yet been fully understood. Through the 20 individual contributions from experts all over the world the present state of knowledge about hot cracking during welding is defined, and the subject is approached from four different viewpoints. The first chapter provides an overview of the various hot cracking phenomena. Different mechanisms of solidification cracking proposed in the past decades are summarized and new insight is particularly given into the mechanism of ductility dip cracking. The effects of different alloying elements on the hot cracking resistance of various materials are shown in the second chapter and, as a special metallurgical effect, the initiation of stress corrosion cracking at hot cracks has been highlighted. The third chapter outlines how numerical analyses and other modelling techniques can be utilized to describe hot cracking phenomena and how such results might contribute to the explanation of the mechanisms. Various hot cracking test procedures are presented in the final chapter with a special emphasis on standardization. For the engineering and natural scientists in research and development the book provides both, new insight and a comprehensive overview of hot cracking phenomena in welds. The contributions additionally give numerous individual solutions and helpful advice for international welding engineers to avoid hot cracking in practice. Furthermore, it represents a very helpful tool for upper level metallurgical and mechanical engineering students.

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.

This proceedings volume contains a selection of papers presented at the symposium "International Conference on High Performance Scientific Computing'' held at the Hanoi Institute of Mathematics of the Vietnam National Center for Natural Science and Technology (NCST), March 10-14, 2003. The conference has been organized by the Hanoi Institute of Mathematics, SFB 359 ''Reactive Flows, Transport and Diffusion'', Heidelberg, Ho Chi Minh City University of Technology and Interdisciplinary Center for Scientific Computing (IWR), Heidelberg. The contributions cover the broad interdisciplinary spectrum of scientific computing and present recent advances in theory, development of methods, and applications in practice. Subjects covered are mathematical modelling, numerical simulation, methods for optimization and optimal control, parallel computing, symbolic computing, software development, applications of scientific computing in physics, chemistry, biology and mechanics, environmental and hydrology problems, transport, logistics and site location, communication networks, production scheduling, industrial and commercial problems.