Thermal Processes in Welding (eBook)

Victor A. Karkhin (Autor)

eBook Download: PDF

2019 | 1st ed. 2019
XIX, 478 Seiten
Springer Singapore (Verlag)
978-981-13-5965-1 (ISBN)

Infos

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. 

Victor A. KARKHIN is a Professor at the Department of Welding and Laser Technologies, Peter the Great St. Petersburg Polytechnic University, Russia as well as an Honorary Doctor of Lappeenranta University of Technology, Finland. Has published more than 300 research and educational papers on the theory of welding processes, strength of welded structures, theory of welding stresses and distortion, mathematical modeling and optimization of technological processes. Has been a lecturer at various universities in the USSR, Germany, Norway and Finland. He is a Commission member of the International Institute of Welding and the International Organization for Standardization. His article 'Inverse Modelling of Fusion Welding Processes' was awarded the Kenneth Easterling Best Paper Award by the International Institute of Welding.

Inhalt

Preface to the English Edition 7
Contents 10
Symbols 14
Abstract 18
1 Energy Characteristics of Welding Heat Sources 19
1.1 Requirements for Welding Heat Sources 19
1.2 Welding Arc 19
1.3 Plasma Arc 34
1.4 Electron Beam 36
1.5 Laser Beam 38
1.6 Gas Flame 39
1.7 Electroslag Pool 41
1.8 Resistance Spot Welding 44
1.9 Resistance Butt Welding 46
1.10 Flash Welding 47
1.11 Friction Welding 47
1.12 Friction Stir Welding 48
1.13 Magnetically Impelled Arc Welding 53
References 54
2 Thermophysical Properties of Metals 59
2.1 Overview 59
2.2 Properties of Steels 62
2.3 Properties of Aluminium Alloys 64
2.4 Properties of Titanium Alloys 67
2.5 Properties of Magnesium 68
2.6 Properties of Copper Alloys 69
2.7 Properties of Nickel 69
References 71
3 Physical Fundamentals of Heat Conduction During Welding 73
3.1 Principal Definitions 73
3.2 Fourier’s Law of Heat Conduction 75
3.3 Differential Equation for Heat Conduction 76
3.4 Boundary Conditions 82
3.5 Accounting for Variability of Thermal Properties 86
3.6 Accounting for the Latent Heat of Phase Transformations 88
3.7 Models for Heat Sources 89
3.8 Schematisation of Heated Bodies 97
References 98
4 Methods for Solving the Problems of Heat Conduction in Welding 101
4.1 Classification of Methods for Solving the Problems of Heat Conduction in Welding 101
4.2 Functional-Analytical Methods for Calculation of Thermal Processes in Welding 102
4.2.1 Source Method 102
4.2.2 Method of Separation of Variables 122
4.2.3 Method of Integral Transformations 127
4.3 Numerical Methods of Calculating Thermal Processes in Welding 131
4.3.1 Finite Difference Method 132
4.3.2 Finite Element Method 140
4.3.3 Boundary Element Method 163
References 170
5 Temperature Fields in Fusion Welding 174
5.1 Temperature Fields of Concentrated Sources 174
5.1.1 Instantaneous Concentrated Sources 174
5.1.2 Stationary Continuous Concentrated Sources 181
5.1.3 Moving Concentrated Sources 185
5.1.4 Rapidly Moving Concentrated Heat Sources 228
5.2 Temperature Fields of Distributed Sources 238
5.2.1 Instantaneous Distributed Sources 239
5.2.2 Stationary Continuous Distributed Sources 266
5.2.3 Moving Distributed Sources 273
5.2.4 Rapidly Moving Distributed Sources 308
References 316
6 Temperature Fields in Welding with Pressure 321
6.1 Resistance Spot Welding 321
6.2 Resistance Butt and Flash Welding 327
6.3 Friction Welding 332
6.4 Friction Stir Welding 333
6.5 Magnetically Impelled Arc Welding 335
References 337
7 Temperature Fields Under Programmed Heat Input 339
7.1 Overview 339
7.2 Temperature Fields of Pulsed Power Sources 341
7.2.1 Point Source on a Semi-infinite Body 343
7.2.2 Point Source in a Slab 351
7.2.3 Line Source in a Plate 353
7.2.4 Plane Source in a Rod 355
7.2.5 Distributed Pulsed Power Sources 357
7.3 Weaving Heat Sources 361
References 366
8 Thermal Cycles of Metal During Welding 369
8.1 General Information 369
8.2 Rapidly Moving Point Source on a Semi-infinite Body 370
8.3 Rapidly Moving Point Source on a Slab 372
8.4 Rapidly Moving Line Source in a Plate 374
8.5 Cooling Time 375
References 378
9 Melting and Solidification of Base Metal 379
9.1 Weld Pool Dimensions 379
9.2 Melting Efficiency of Heat Source 380
9.2.1 Rapidly Moving Point Source on a Semi-infinite Body 380
9.2.2 Rapidly Moving Line Source in a Plate 381
9.3 Solidification of Weld Pool 381
9.4 Effects of Latent Heat 388
References 393
10 Heating and Melting of Filler Metal 396
10.1 Heating and Melting of Covered Electrodes 396
10.2 Heating of Electrode Wire 397
10.3 Melting of Electrode Wire 400
10.4 Heating and Melting of Filler Wire 403
References 405
11 Inverse Heat Conduction Problems in Welding 406
11.1 Formulation of an Inverse Heat Conduction Problem 406
11.2 Solution of an Inverse Heat Conduction Problem 410
11.2.1 Zero-Order Method 412
11.2.2 First-Order Method 415
11.2.3 Second-Order Method 416
References 421
12 Optimisation of Welding Conditions 425
12.1 Optimum Heat Input in Girth Welding of Thin-Walled Small Diameter Pipes 425
12.2 Optimisation of Pulsed Power Welding Conditions 427
12.3 Optimisation of Strip Electrode Shape for Cladding 432
12.4 Optimisation of Welding Conditions with Restrictions for Peak Temperature 435
12.5 Optimisation of Plate Edge Preheating Conditions in Butt Welding 438
12.6 Minimisation of Transient and Residual Stresses 443
12.6.1 Optimisation of Local Heating Conditions During Welding to Prevent Hot Cracking 443
12.6.2 Minimisation of Longitudinal Residual Stresses Using Additional Local Heating During Welding 447
12.6.3 Optimisation of Welding Conditions for Obtaining Required Residual Stresses 449
References 452
13 Prediction of Local Microstructure and Mechanical Properties of Welded Joint Metal with Allowance for Its Thermal Cycle 455
13.1 Microstructural Zones of Welded Joint 455
13.2 Microstructure of Heat Affected Zone Metal in Single-Pass Welding 457
13.3 Microstructure of Heat Affected Zone Metal in Multi-Pass Welding 464
13.4 Mechanical Properties of Steels in the Heat Affected Zone and Weld 468
13.4.1 Mechanical Properties of Heat Affected Zone Metal 468
13.4.2 Mechanical Properties of Weld Metal 471
13.5 Microstructure and Mechanical Properties of Aluminium Alloys 473
13.6 Effect of Thermal Cycles on Mass Diffusion Processes in Welding 473
13.7 Optimisation of Inert Gas Tungsten Arc Welding Conditions for Stainless Steel 480
References 482
Index 485

Produkt-Details

• Erscheint lt. Verlag: 15.5.2019
• Reihe/Serie: Engineering Materials
• Reihe/Serie: Engineering Materials
• Zusatzinfo: XIX, 478 p. 284 illus.
• Sprache: englisch
• Original-Titel: ТЕПЛОВЫЕ ПРОЦЕССЫ ПРИ СВАРКЕ
• Themenwelt: Naturwissenschaften ► Physik / Astronomie ► Thermodynamik
• Themenwelt: Technik ► Maschinenbau
• Themenwelt: Wirtschaft ► Betriebswirtschaft / Management ► Logistik / Produktion
• Schlagworte: fusion welding processes • heat sources in a cylinder • heat sources in a plane layer • heat sources in a semi-infinite body • microstructure prdeiction • moving heat sources • pulsed power sources • Rosenthal and Rykalin • weaving sources
• ISBN-10: 981-13-5965-2 / 9811359652
• ISBN-13: 978-981-13-5965-1 / 9789811359651