iii Preface Welding Fundamentals is written for secondary and postsecondary students, apprentices, journeymen, and individuals who wish to learn to weld. This book covers the equipment and techniques used for the welding and cutting processes most often employed in industry today. These processes are shielded metal arc welding, gas metal arc welding, fl ux cored arc welding, gas tungsten arc welding, oxyfuel gas cutting and welding, and resistance welding. Welding Fundamentals contains information about welding careers and the physics of welding. Technical information regarding weld inspection and testing, welder qualifi cation, drawing interpretation, and welding symbols is also included. General welding safety is covered in Chapter 2. Safety information and cautions are also written into the text wherever they apply. Safety information and precautions are printed in red, so that they will stand out. The text is organized into eight sections. Each section is composed of one or more chapters that describe processes, explain procedures, or present general information relating to the topic of that section. A section can be studied independently or in sequence with other sections. The fi rst section provides general information about welding. The topics presented in these chapters include welding careers safety an overview of welding and cutting processes a brief discussion of the physics behind welding information about welding-related math, measurement, and layout a close look at the different weld joints and welding positions and information about drawings and welding symbols. Sections 2–8 present detailed information about welding and cutting processes. This study of processes begins in Section 2 with a close look at shielded metal arc welding. The subsequent sections present detailed information about gas metal and fl ux-cored arc welding, gas tungsten arc welding, plasma arc cutting, oxyfuel gas processes, and resistance welding. The fi nal section discusses technical information that is of practical importance to welders. The topics covered in these chapters include pipe and tube welding, special welding and cutting processes, robotics in welding, inspecting and testing welds, and welder certifi cation. The end of the book contains several useful appendices and an extensive glossary of technical terms. You may begin your study of welding with any section and progress in any desired sequence from section to section. However, when you use the Lab Workbook for Welding Fundamentals, we recommend that Chapter 8, Welding Symbols, be studied early. Welding symbols are used in the Lab Workbook to describe the sample joints and welds for each job assignment. Before attempting any welding process that uses a pressurized gas, Chapters 24 and 25 should be studied. Welding Fundamentals is written in an easy-to-read and understandable style. Care was taken to stress the welding terms approved by the American Welding Society (AWS). In cases where nonstandard terms are used by some people in the trade, such terms are often given in parentheses after the correct AWS term. The book is extensively illustrated with drawings and photographs to show the various processes or welding techniques. Many tables and charts are provided to help you select the proper variable values required to make a good weld. Images include photographs of industrial welding applications and photographs of practice welds in progress. Equivalent SI metric measurement units are shown in parentheses following US customary measurements. You should read the caption accompanying each illustration, since the caption often gives information that is not covered in the text. Review questions are provided at the end of each chapter to test your knowledge of the information covered. Additional end-of-chapter activities help you apply your welding knowledge to other academic areas. Many chapters include practice exercises to test your skills as a student welder in completing various welding tasks. It is our sincere hope that Welding Fundamentals will help you progress in an organized manner toward a mastery of the essential welding skills.