iii Preface Modern Welding is an authoritative and technically correct text written for use by students and teachers in secondary schools, colleges and universities, technical, and trade schools. It is also suitable for use by individuals who wish to learn independently about contem- porary processes and techniques used in welding. For this edition, it has been expanded and updated to cover the knowledge and skills required for both AWS SENSE Level I and Level II certifi cation. The book has also been correlated to Precision Exams Welding Techni- cian certifi cation standards. Modern Welding provides you with an understanding of virtually all the welding and cut- ting processes used in production and repair today. This book covers the theory, fundamen- tals of operation, equipment used, and techniques recommended for all of the welding and cutting processes in commercial use. The many tables and charts included in Modern Welding provide information regarding recommended settings for the variables involved in the various welding processes. These tables include the recommended amperage and voltage settings, wire feed rates, electrode sizes, inert gas selections, welding speeds, gas pressures, tip sizes, and much more. General shop safety, safety attitudes, and specifi c welding shop safety practices are covered in Chapter 1. Safety information and cautions are also printed in bold, red type throughout the text, wherever they apply. Chapters 2 and 3 cover print reading and the interpretation of the American Welding Society welding symbols found on welding prints. Chapter 4 is an overview of welding and cutting processes that are covered in detail later in the book. The remainder of the text is divided into nine sections, each covering a different welding process or group of related welding processes. Chapter 33 covers the subject of get- ting and holding a job in the welding industry. Technical information that may be required while working in the welding industry is included in Chapter 34. An extensive Glossary of Welding Terms is provided at the end of the book. Modern Welding may be studied in order from Chapter 1 to Chapter 34, or it may be used to study welding processes in any desired order. Each section stands alone and does not rely on previously acquired knowledge. Modern Welding is extensively illustrated with full-color photographs, as well as drawings that have been color-coded to help you better understand each welding process and its equipment. Be sure to read all fi gure captions— they may contain details that are not included in the text. Measurements are generally shown in dual form: US Customary followed by SI (metric). Welding terms throughout the text conform to the usage in the AWS Standard A3.0:2010, Standard Welding Terms and Defi nitions. Nonstandard or “trade” terms, when given, are clearly identifi ed. The topics covered in Modern Welding are presented in a logical sequence designed to make learning and teaching the technology of welding easier and more effective. William A. Bowditch Kevin E. Bowditch Mark A. Bowditch