Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. PowerPoint to accompany Welding Principles and Practices Third Edition Sacks and Bohnart 1 Chapter 1 History of Welding

What is Welding? Break into groups and discuss what you think welding is Can you think of types of welding? 1 - 2

Overview Welding is joining two pieces of metal by:Welding –Heating to temperature high enough to cause softening or melting –With or without application of pressure –With or without use of filler metal Usually best method to use when fastening metal 1 - 3

Uses of Welding Constructing and manufacturing: 1 - 4

History of Metalworking Welding began more than 3000 years ago –Hot or cold metals hammered to obtain forge weld 1 - 5

History of Metalworking Bronze developed between 3000 and 2000 B.C. Iron became known to Europe about 1000 B.C. –Several thousand years after use of copper –Replaced bronze as metal used in manufacture of utensils, armor and other applications after 800 B.C

History of Metalworking Working of metals followed one another in great ancient civilizations –From copper, to bronze, silver, gold, and iron 1 - 7

Early Developments in Welding Edmund Davy discovered acetylene at beginning of nineteenth century = Oxy- Acetylene Sir Humphrey Davy discovered the electric arc in 1801 = Arc Welding –Concerned with use of arc for illumination –Demonstrated possible to maintain high voltage arc for varying periods of time by 1809 Workable electrical generating devices invented and developed on practical basis by These inventions were forerunner of present arc welding process.

History of Metalworking first commercial oxyacetylene welding torch at turn of the century Electric arc welding method used in US until about 1920 –Handicapped because of welds produced by these bare electrodes not as strong as metal being welded Welding arc very unstable No Flux 1 - 9

History of Metalworking Technology of welding progressed slowly until World War I –Demands of war called for improved methods of fabrication –End of war, welding widely accepted Research on coated electrodes through 1920s resulted in electrode coatings and improved core wire

Multipass Welds Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Ability to make multipass welds such as this one, on plate and pipe, led to growth of industry. Welds are sound and have uniform appearance. Pass 1 Pass 2 Pass 3

History of Metalworking Stick welding process –Advanced rapidly due to electrode coatings and improved core wire –Now called shielded metal arc welding (SMAW) –Uses 14” stick electrode that conducts current from holder to work –Arc melts electrode, creating weld Stick welding

Tungsten Inert Gas (TIG) Process Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. An aluminum weld made using the TIG process. The welding of aluminum is no longer a problem and can be done with the same ease as that of steel.

GMAW (metal inert gas: MIG) Process Concentrates high heat at a focal point Produces –Small heat-affected zone –Narrow bead width –Deep penetration –Faster welding speed Now used in all industries Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Responsible for over 70 percent of welds being performed today. St Louis Car. Co.

Industry Demand Over 90 welding processes Force new and improved developments in machines, gases, torches, electrodes, procedures, and technology Constant research for new metals done by shipbuilding, space and nuclear industries –Needs Spur research in welding

Welding Associations American National Standards Institute (ANSI) American Petroleum Institute (API) American Society of Mechanical Engineers (ASME) American Welding Society (AWS) American Bureau of Shipping (ABS) Provide guidance and standards relating to the welding industry.

Resistance Welding Includes spot welding, seam welding, and other similar processes performed on machines Operators usually taught on job –Semiskilled workers do not need specific hands-on- welding skills

Arc and Gas Welding Welders have almost complete control of the process –Must know properties of metals to weld; which weld process to use; and how to plan, measure, and fabricate

Welding Positions As well as flat and horizontal Vertical Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Miller Electric Mfg. Co. Overhead General Electric Corp.

Weld Positions

Qualifications and Personal Characteristics Welders certified for ability to do their work and have work pass inspection. Required to pass periodic qualification tests Certifications issued according to kind and gauge of metal and specific welding process Can hold several different certifications simultaneously

Example of Magnetic-Particle Testing in Building Weld testing and inspection give proof of the soundness of welds. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Circlesafe Aerosol/Circle Systems, Inc.

Master Welder Job Examples Welds in these tanks must meet X-ray requirements and pass a dye penetrant test. Tanks are often lined with a very thin layer of pure silver. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Nooter Corp Creating Art! Enrique Vega

Master Welder Master craftsperson Able to weld all steels and alloys –Plus nickel, aluminum, titanium, zirconium, and their alloys and claddings Welds of highest quality Welds meet requirement of job –Delicate welding of silver and gold –Heavy pressure vessels requiring 4-inch plate

Welding Occupations Requiring a High School Education Welding operator Welding fitter Combination welder Master welder Welding supervisor Welding analyst Inspector Welding foreman Welding superintendent Equipment sales Sales demonstrator Sales troubleshooter Welding instructor Robotics welder operator Jog or fabrication shop owner

Welding Occupations Requiring a College Education Welding engineer (metallurgical) Welding development engineer Welding research engineer Technical editor Welding professor Certified welding inspector (AWS/CWI) Corporation executive Owner of welding business Sales engineer

So... What is welding? Alright so now what is welding?