Welding: Principles & Practices - Tapa dura

http://www.aws.org/w/s/wj/2005/01/016

BY R. DAVID THOMAS, JR.

Welding Principles and Practice, by Raymond J. Sacks and Edward R. Bohnart. Hardbound, 81/2 x 11 in., 1312 pages, third edition. Published 2004 by McGraw-Hill Companies, Inc., 1221 Avenue of the Americas, New York, NY 10020; (212) 512-2000; http://books.mcgrawhill.com/getbook.php?isbn=0078250609&template=. Price is $92.33.

This mammoth volume is a tremendous contribution for training welding operators of all degrees of expertise. It is divided into the following five units: Introduction to Welding and Oxyfuel; Shielded Metal Arc Welding; Arc Cutting and Tungsten Arc Welding; Gas Metal Arc, Flux Cored Arc, and Submerged Arc Welding; and High Energy Beams, Automation, Robotics, and Weld Shop Management. Diligent students who are challenged to master the skills of the welding processes and hope ultimately to advance to management positions will have in this volume a valuable resource, not only as he and she learn the basics, but also throughout their careers.

One of the textbook's great strengths is the style of writing that will allow young persons of high school age to comprehend the complexities that they will encounter as they embark on their journey toward a welding profession. It is to be hoped that its size and especially its weight (61/2 lb, 3 kg) will not become a deterrent. If a reader will read the opening chapter, he or she might well become entranced by the four-page overview and history.

This is followed by a section, "Welding as an Occupation." Here young women will be encouraged by the statement, "Many women find the work highly satisfying and are paid well at a rate equivalent to that of men." Then, they can see a photo of a woman arc welding in the overhead position.

Its chapters are sprinkled with brief marginal notes titled "Shop Talk," "Job Tip," or "About Welding," all of which offer a change of pace from concentration on study. Much of its length and heft results from its multitude of photos, sketches, and diagrams that add to interest and comprehension. Supplements to this book include an instructor's manual, student's workbook, and CD with PowerPoint lecture slides.

At the end of each chapter is a multiple choice test and review questions. There are also two exercises proposed under the heading Internet Activities, which start out with, "Using your favorite search engine..."; they encourage the student to discover the wealth of information on the Internet.

Having spent a career involved with filler metals, I decided to take the multiple choice test without first reading Chapter 12 on Shielded Metal Arc Electrodes. I scored 7 out of 10 with two of the answers half right. My conclusion was that it was a good test.

One feature of the book is the detailed discussion and illustrations of the welding equipment and the related tools used for assembly and inspection. All too often this aspect of training courses is overlooked, and the students are expected to absorb the essentials during use. Moreover, in each chapter relating to processes, an emphasis is on safe practices. Toward the end of the volume, on pages 1121 to 1156, Chapter 31, Safety, thoroughly covers the subject for both arc welding and oxyfuel welding. One would hope that students are referred to sections of that chapter before they embark on the practice jobs in the earlier chapters.

The chapters describing the individual welding processes are generally followed by chapters devoted to practice welds. As the techniques become ever more complicated, the reader must interpret shop drawings that illustrate the tasks. It is one thing to develop the skill to create acceptable welds, but one aspiring to supervise a welding department must learn the devices used by designers to describe the assembly.

Chapters 29 and 30 give details of drawing conventions, including tables of symbols for various types of welded joints. A student should be shown where in the volume the symbols are found when he or she faces the drawings in the practice job chapters. Present and new school instructors will most certainly want to evaluate this extensive program for training young people in welding technology. Many may already make use of instruction manuals offered by schools associated with Hobart, Lincoln, and other welding equipment suppliers. Several AWS publications, such as EG2.0-95 and EG3.0-96, offer guides for training entry-level and advanced welders, respectively.

The AWS Schools Excelling through National Skills Education (S.E.N.S.E.) columns on the tables of practice jobs appear at the end of chapters relating to arc welding. Chapter 15 covering pipe welding has many notes including references to ASME and API code certification tests, and AWS B2.1, Welding Procedure Specifications. It would have been helpful if the index included references to the AWS S.E.N.S.E. program, listing pages to these tables.

Young people undergoing training for careers in welding today should become familiar with the metric system of measurements. It would be awkward as in other AWS documents to insist that every dimension used would list both the U.S. Customary Units, in., ft, etc. as well as the rational metric equivalents. Nevertheless, it is regrettable that training of young people does not immediately require they use and learn to think in metric units. One recognizes that welders in U.S. industry today only too rarely require familiarity with metrics; yet the day is not too far off when welding schools should make greater use of the SI system of measurement in their training programs.

Fortunately, the appendix in this volume has seven tables for use when metric units are needed. Additional tables provide the data on standard drill and pipe sizes. Another, besides giving temperature equivalents in degrees Fahrenheit and Celsius, provides the melting points of metals and alloys, and the color scale for estimating temperatures. -------------------------------------------------------------------------------- R. DAVID THOMAS, JR., is a Fellow of the American Welding Society, Miami, Fla. (Welding Design and Fabrication 2005-01-16)

This text introduces students to a solid background in the basic principles and practices of welding. It first introduces fundamental theory of the welding process (gas arc, semi-automatic, automatic, and robotic welding) and then provides practice jobs so students develop manipulative skills and technical understanding. Metals and their welding characteristics, safety practices, welding symbols, and the fundamentals of print reading are all covered.