Preface

The book is divided into three parts and twelve chapters. Section One addresses automation and control in welding. Chapter 1 presents a bibliographical review of the scientific literature related to qualitative and quantitative indexes to evaluate the stability of the Gas Metal Arc Welding (GMAW) process. It also examines the factors that affect stability and stability indexes. Chapter 2 introduces the reader to how data mining processes, machine learning, deep learning, and reinforcement learning techniques have had good results in the analysis and control of systems as complex as the welding process. Chapter 3 shows how different sensing, modelling, estimation, and control techniques are used to overcome the challenge of welding bead geometry on-line control. Chapter 4 discusses selected sensing techniques and estimation algorithms used on-line for monitoring and collecting values on the welding parameter process. Special attention is given to sensor fusion techniques. Some real applications and innovative research results are also discussed.

Section Two illustrates some modern welding processes. Chapter 5 looks at the results of metallographic and micro X-ray spectral analysis investigations of dissimilar brazed joints of molybdenum–stainless steel and shows the features of formation of brazed seams at the application of brazing filler metals of a Cu-Mn-Ni(Me) system. Chapter 6 lists some examples of errors that can occur in soldering, as well as describes selected defects such as non-wettability of the solder pads, dewetting, wrong solder mask design, warpage, head-in-pillow, cracks in the joints, pad cratering, black pad, solder beading, tombstoning, dendrites, voids, flux spattering from the solder paste, popcorning, and whiskers. Chapter 7 presents the technology for obtaining ultra-hard layers based on tungsten carbide (WC) and titanium carbide (TiC) by the arc spraying process, using a classic spray device equipped with a conical nozzle system and tubular wire additional material containing ultra-hard compounds (WC, TiC).

Section Three addresses some important thermal-mechanical treatments related to welding quality. Chapter 8 describes how to creep strength at high temperature could be improved by a microstructural optimization through nano-precipitation, guided by computational thermodynamics and thermomechanical control process optimization. Chapter 9 presents a heat treatment route as an important route for the development of high-strength alloy steel. Many heat treatment processes are applied depending on alloy compositions and desired mechanical properties. Chapter 10 categorizes heat treatment of metastable beta titanium alloys into two steps: solution treatment in beta or alpha+beta phase field and ageing at appropriate lower temperatures. The chapter pays special attention to heat treatment of beta titanium alloys for biomedical applications because of the growing interest in this class of alloys. Chapter 11 examines the important role that grain boundary design plays in achieving required end mechanical properties in the final product form: hot rolled or cold rolled coil. Grain refinement in steel design is a particularly attractive strengthening mechanism, as it benefits both fracture toughness and mechanical behaviour at lower temperatures, particularly in the case of high

**II**

**Section 3**

Routes *by Nicky Kisku*

in Steel

*by Gaurav Bhargava*

Thermomechanical Treatments

*and Nageswara Rao Muktinutalapati*

Welding Residual Stresses to the Electric Arc

*by Lino Alberto Soares Rodrigues, Ednelson da Silva Costa, Tárcio dos Santos Cabral and Eduardo Magalhães Braga*

*and Carlos Capdevila*

Metal Thermo-Mechanical Processing **161**

**Chapter 8 163**

**Chapter 9 187**

**Chapter 10 203**

**Chapter 11 221**

**Chapter 12 233**

High-Chromium (9-12Cr) Steels: Creep Enhancement by Conventional

Strengthening of High-Alloy Steel through Innovative Heat Treatment

*by Sudhagara Rajan Soundararajan, Jithin Vishnu, Geetha Manivasagam* 

Grain Boundary Effects on Mechanical Properties: Design Approaches

*by Javier Vivas, David San-Martin, Francisca G. Caballero* 

Heat Treatment of Metastable Beta Titanium Alloys

strength and line pipe steels. Chapter 12 presents a contextualized approach to destructive and non-destructive techniques used to measure residual stresses (RS) generated by arc welding. It also discusses the influence of distortion and stress on welded structures and presents possible control techniques.
