Picture Credits
The authors would like to express their thanks and appreciation to the following organizations which provided invaluable illustration source materials for this book.
The American Welding Society granted us permission to use illustrations from several publications, including:
•Welding Handbook, Volume 1, Welding Technology
•Welding Handbook, Volume 2, Welding Processes
•Introductory Welding Metallurgy
•Welding Inspection Technology
•Standard Welding Terms and Definitions
•Brazing Handbook
•Structural Welding Code — Steel, ANSI/AWS D1.1
These publications are the classics of the welding industry and they greatly helped us illustrate the text. AWS official terminology is used throughout the book.
ESAB Welding and Cutting Products graciously gave permission to use illustrations from their publication The Oxyacetylene Handbook.
Lincoln Electric Company kindly provided product technical information on SMAW electrodes and permission to reproduce illustrations from their publication Weldirectory—Stick Electrodes for Carbon and Low Alloy Steel.
Thermadyne/Victor provided technical information and illustrations on oxyacetylene torches, check valves and flame arrestors.
The authors want to thank the reviewers of this book: John Brady, Gene Lawson, Bob Saddler, David Randal, Professor Richard Hutchison and his wife Catherine.
Thanks also to Lawrence Smith and Joan Cordova for their assistance in completing changes for the second edition.
The authors had the following objectives in mind when writing this book:
•Develop an easy-to-read, concise book with all the technical and safety information a beginning welder needs.
•Use a question-and-answer format to divide this information into small, easily understandable blocks.
•Provide illustrations to clarify and detail every explanation.
•Eliminate non-essential items to prevent overloading the reader.
•In a single chapter cover each major, commercially important process: oxyacetylene welding, oxyfuel cutting, brazing & soldering, SMAW, GMAW/FCAW, and GTAW/PAW.
•Describe less important welding processes in a survey chapter.
•Explain the effects of welding heat on metals.
•Present welding power supply and electrical safety issues.
•Introduce the beginning welder to weld inspection, welding symbols and qualification and certification issues.
Because this book initially did not provide much practical how-to-do-it advice in this expanded first edition we have added a chapter on fabrication and repair tips: assembling angle iron frames, repairing cracked heavy truck C-channels, and soldering copper tubing. These are relatively common tasks the welder will see and we want him to know how to do them.
We have not included torch manipulation instructions. This is a hands-on skill that is best learned from classroom demonstrations, personal instruction.
Although this book is primarily based on English measurement units, we have usually included metric units also.
| WILLIAM L. GALVERY, JR. | FRANK M. MARLOW |
| Costa Mesa, California | Huntington Beach, California |
The chapter of knowledge is a very short one, but the chapter ofaccidents is a very long one.
Philip Dormer Stanhope
Introduction
Oxyacetylene welding was first used industrially in the early years of the twentieth century. Although this process makes excellent welds in steel, it is little used for welding today except for a few specialties (light aircraft, race car frames and American Petroleum Institute natural gas distribution), since there are other more efficient welding processes available. However, oxyacetylene has many other important uses: cutting, hardening, tempering, bending, forming, preheating, postheating, brazing, and braze welding. Because of the precise control the welder has over heat input and its high-temperature flame, together with its low equipment cost, portability, and versatility, it remains an essential tool. No industrial shop is complete without an oxyacetylene outfit. As with all effective tools, using oxyacetylene carries risk. We will cover the theory and use of oxyacetylene equipment so you can use them with confidence and safety. It will also prepare you for the next chapter on oxyfuel cutting, because many components and issues are common to both processes.
Process Name
What is the name covering all welding processes using oxygen and a fuel gas?
Oxygen fuel (oxyfuel) welding.
What is the American Welding Society (AWS) abbreviation for oxyfuel welding?
The abbreviation for all oxyfuel welding processes; those using oxygen and any fuel gas is OFW.
A particularly important member of the OFW process family is oxyacetylene welding. What is the AWS abbreviation for this process?
The abbreviation for oxyacetylene welding is OAW. Note that OAW is just one member of the OFW family.
Equipment
Figure 1-1 shows and labels the components of the basic oxyacetylene welding equipment (outfit) showing how they are connected.
Figure 1–1A drawing of oxygen acetylene welding equipment
Process
How does oxyacetylene equipment perform the welding process?
Oxygen and acetylene gases when combined, in the proper proportions, in the torch handle’s mixing chamber, produce an approximately 5600°F (3100°C) flame at the torch tip. This flame melts the edges of the base metals to be joined into a common pool. Sometimes additional filler metal is added to the molten pool from a welding rod. When this common pool cools and the metal freezes solid, the joined metals are fused together and the weld complete.
What are some advantages of the OAW process?
•Low cost
•Readily portable
•Excellent control of heat input and puddle viscosity
•No external power required
•Good control of bead size and shape
•Fuel mixture is hot enough to melt steel
Setup (and related safety)