20.1 History of Welding Ferrous Metals
David Colameco, M.Ed.
The American Welding Society defines welding as, “A joining process producing coalescence of materials by heating them to the welding temperature, with or without the application of pressure or by the application of pressure alone, and with or without the use of filler metal” (AWS, 2020). This definition covers a lot of different joining techniques, which makes the world of welding such a rewarding experience and career that can go in many different directions.
Welding has been performed for thousands of years. Metals were likely discovered by our ancestors when making fires near stones on sand. The heat from the fire melted the metal contained within the stones, which then oozed out. The importance of sand is that it makes solidified metal more visible to the naked eye, especially if there are only small quantities of metal that exits from the stones. Our ancestors then found ways to use the metal to change their lives; through improved quality of life, hunting, and defense or military purposes. Metals play such an important role in the development of civilizations that historians name whole periods of time after them, such as the Bronze Age and Iron Age.
The benefits of metal to societies are the driving force for metallurgical advancements. All of us strive to be better people for ourselves, friends and/or families, and just like our bright and dark points in our pasts, so too do societies and their uses of metal. The authors of this book and your instructors are introducing welding to you so you can enter a rewarding career that benefits not only your life but society as well.
Before we start discussing welding, it is important to discuss some other joining processes you may have worked with or heard of to put them into context with welding: soldering and brazing. The main difference between welding, soldering, and brazing, are the temperatures that each process operates. Because welding has expanded so much, some welding processes may operate at lower temperatures which were previously used to define soldering and brazing regimes.
Soldering generally occurs at the lowest temperatures where only the solder (applied like a filler metal) melts and the base metal does not. As with soldering, brazing does not melt the base material. More modern definitions may remove the temperature difference, but for our purposes of introducing the concepts the older definition is acceptable. Our focus is on welding.
Modern mass production welding first started using oxy fuel processes, such as oxy-acetylene. Today, oxy-acetylene is used more for cutting base material than it is used for welding, your technical program at school probably offers oxy-acetylene welding with a focus on cutting. Oxy-acetylene is a high heat process that is great for metals such as copper which have high thermal conductivities which makes heating them up a time consuming process. A chapter on Oxy-Acetylene cutting has been included in this book. Figure 20.1 shows a welder in 1942, using the Oxy-Acetylene process to weld pipe together.
Acetylene gas was first discovered by chemist Edmund Davy in 1836. Yet it would be many years later that the oxy-acetylene welding process was invented in 1903 by French engineers Edmond Fouché and Charles Picard (Aquasol Corporation, n.d.). Similarly in history, electricity generation was invented much earlier than many of the practical uses. Electric generators were invented in the 1830’s, and Thomas Edison invented the lightbulb in 1879. Electricity was initially used to replace the need to burn candles for light.
Early pictures of Shielded Metal Arc Welding (SMAW) welding are shown in Figure 20.2 of welding in Atlanta, Georgia at a Farm Security Administration warehouse depot.
Figure 20.3 is entitled “Farm boy using welding equipment” in 1942 and archived by the US Library of Congress. This farmer benefited from a US Government initiative called the U.S. Rural Electrification Administration (REA) where the US government made low cost loans to farmers who banded together to bring electricity to rural areas where they had farms. The significance of this is that as electricity was made available at a reasonable price, processes such as electric arc welding were widely adopted by the masses.
Welding as a process adopted by industry really took off during World War II. World War II was significant in our history because it led to the large mobilization of a fighting force that was sent across the globe. This resulted in large numbers of fighting aged men being shipped overseas and working aged women being recruited to help with the war effort. The US government started a massive advertising campaign to break down the barriers that employers and women workers had towards industrial work. The contributions of women in Figure 20.4 and Figure 20.4 cannot be overstated. As welders they are part of our proud history and contributions to America.
Today welding of ferrous metals continues to be a process that is found in large institutions such as industry, government, and academia, but also for the everyday person wanting to weld in their shop to make small repairs.
Development of welding ferrous metals
Welding ferrous metals requires a ferrous base metal, meaning the metal is mostly iron, a controllable heat source capable of melting the base material and filler metal (if used), and the application of the heat source to the base material in a manner that produces a weld that meets mechanical and quality requirements.
As mentioned above, oxy-acetylene welding was one of the first welding processes used in modern history to join metals. Figure 20.5 shows the base material, oxy-acetylene torches in the welders right hands, and the filler metal in their left hands.
Oxy-fuel welding can be a “dirty” process that produces a lot of soot. If your school has an oxy acetylene welding station, you may have noticed that a black coating of soot exists on the surfaces of the station such as insulating bricks. Excessive carbon can be created depending on the type of flame that is used: carburizing, neutral, and oxidizing flames with carburizing flames producing the most carbon.
Electric arc welding is a much more convenient and controllable welding process. Great advances have been made in welding power supplies and filler materials to improve the quality and durability of weldments in service. Welding power supplies are complex, just like other consumer electronics that we use today, such as cell phones. These power supplies are used to produce higher quality welds with processes such as Gas Metal Arc Welding (GMAW), Flux Cored Arc Welding (FCAW) and Gas Tungsten Arc Welding (GTAW) by making corrections to the arc and heat input due to the inconsistencies of having a person welding vs. a robot. Highly trained welders are fairly steady in maintaining an arc length, however even the best welder may deviate slightly closer or further away from the weld pool unintentionally. Chapter 5 Welding Machines discusses power supplies in more detail.
SMAW was the welding process that was adopted broadly by industry for welding due to its versatility, and relatively inexpensive equipment. A motor generator or building wall receptacle that can supply enough power for a welding machine, welding leads, electrodes, and base material are all that is required. The first electrodes were bare wire electrodes. Some theories state that the original experimenters using wire electrodes discovered that rusty electrodes welded better (Cary, 1998, as cited in Miller Electric Manufacturing Co., 2020). This led to the use of flux coatings on a solid metal wire that we are all familiar with today. As time progressed, the flux coatings for SMAW electrodes got more complex by adding elements that remove unwanted impurities that have negative impacts on the weld. Aluminum is one such element that is used as a deoxidizer because aluminum readily bonds with oxygen. These elements then float to the top of the weld pool and form the coating we, as welders, know as slag.
Basics of welding ferrous metals
Welding metallurgy is the study of welding metals based upon the chemical and mechanical properties of the weldment once all welding processes pre-weld, during the weld, and post weld have been completed.
The most important thing a welder can do when performing code welds is to follow the Welding Procedure Specification (WPS) word for word. A certified welder’s value comes not only in their demonstrated skill to perform a weld to specifications, but you are also providing assurance that the welds you produce are of the expected quality and material properties. By following the WPS you are producing a weld that has been tested and approved for the in service application as intended. If you do not follow the welding procedure, your value as a certified welder ceases to exist and may lead to loss of certification and possibly disciplinary action by the organization you received your certification from such as the American Welding Society.
The reason the WPS is so important to follow is because the materials, temperatures, processes, allowed cleaning methods, and procedure of placing weld beads, were all determined through experience followed by destructive testing to produce a weld with the required material properties such as strength, to successfully operate in in-service conditions. When a weld or other fabrication fails on a bridge, building, ship or other structure where public safety is threatened, there is an investigation by government authorities and other organizations such as insurance companies. The records for that fabrication are reviewed and authors interviewed if needed, the fabricators and engineers are interviewed, and destructive testing is carried out to determine the cause of failure. As a welder you are a professional in a rewarding career; don’t jeopardize losing your ability to continue in your career by not welding to the specifications you are provided.
Welding ferrous materials to a code or not, requires welders to use their experience and good welding practices along with professional judgment. Weld joints, base material, welding process, and filler metals if used based on process, all come together as inputs that determine which guidance is used for welding.
Uses of ferrous metals in industry today
Ferrous metals are the most widely used in the world today because of their material properties of both strength, durability, and weldability, along with relatively low material cost. Weldability refers to the ease that a material can be welded. Most welding schools start students out welding ASTM A36 mild steel because it is used throughout industry for structural applications, it is relatively low cost, and most importantly because it is easily weldable. Starting a student out on a material that first requires mastery of welding would only lead to frustration.
Ferrous metals are used in structural applications as mentioned above but more specifically in the steel that makes up buildings, bridges, ships, pipelines, and other containers. In applications where ferrous metals would corrode, they are sometimes clad with stainless steel or other corrosion resistant material so the steel provides most of the strength of the fabrication and the cladding is what comes in contact with the corrosive substance, such as in a tank. By using ferrous material with a thinner clad material, the fabrication has both the strength and corrosion resistance required, but at a reduced cost.
Attributions
- Figure 20.1: Gas welding a joint in a line of spiral pipe at the TVA’s new Douglas Dam on the French Broad River, Tenn. This dam will be 161 feet high and 1,682 feet long, with a 31,600-acre reservoir area extending 43 miles upstream. With a useful storage capacity of approximately 1,330,000 acre-feet, this reservoir will make possible the addition of nearly 100,000 kw. of continuous power to the TVA system in dry years and almost 170,000 kw. in the average year by Alfred T. Palmer, Library of Congress, Prints & Photographs Division, Farm Security Administration/Office of War Information Color Photographs in the Public Domain; The contents of the Library of Congress Farm Security Administration/Office of War Information Color Photographs are in the public domain and are free to use and reuse.
- Figure 20.2: Welding axle. FSA (Farm Security Administration) warehouse depot. Atlanta, Georgia by Marion Post Wolcott, 1910-1990, Library of Congress, Prints & Photographs Division, Farm Security Administration/Office of War Information Black-and-White Negatives. in the Public Domain; The contents of the Library of Congress Farm Security Administration/Office of War Information Black-and-White Negatives are in the public domain and are free to use and reuse.
- Figure 20.3: Dunklin County, Missouri. Farm boy using welding equipment on a farm that receives U.S. Rural Electrification Administration (REA) power by Arthur Rothstein, 1915-1985, Library of Congress, Prints & Photographs Division, Farm Security Administration/Office of War Information Black-and-White Negatives. in the Public Domain; The contents of the Library of Congress Farm Security Administration/Office of War Information Black-and-White Negatives are in the public domain and are free to use and reuse.
- Figure 20.4: Line up of some of women welders including the women’s welding champion of Ingalls [Shipbuilding Corp., Pascagoula, MS] by Department of Labor, Women’s Bureau in the Public Domain; United States government work
- Figure 20.5: Nashville, Tennessee. Welding parts for fuel pumps. Vultee Aircraft Corporation plant by Jack Delano, 1914-1997, photographer; Library of Congress, Prints & Photographs Division, Farm Security Administration/Office of War Information Black-and-White Negatives. in the Public Domain; United States government work. The contents of the Library of Congress Farm Security Administration/Office of War Information Black-and-White Negatives are in the public domain and are free to use and reuse.
A process where the base material does not melt but the filler metal does melt. Soldering is similar to brazing but is performed at a lower temperature than brazing.
A process where the base material does not melt but the filler metal does melt. Brazing is similar to soldering but is performed at a higher temperature than soldering.
Refers to the gasses of oxygen and acetylene that are used for welding.
A metal where iron is the main base consituent.
Welding metallurgy is the study of welding metals based upon the chemical and mechanical properties of the weldment once all welding processes pre-weld, during the weld, and post weld have been completed.
The operating environment a weldment will experience such as temperatures and pressures.
Stainless steel is a group of steel alloys that contain levels of chrome and other corrosion resisting alloying elements that give the materials properties that it "stains' less than ordinary steel. See the chemical compositions of stainless steel grades for quantities of alloying elements.