From Metal Electrodes to Metal-Cored, A Brief History of Filler Metals
History is a vague and mysterious thing. Its events are undeniably the result of the economic, political and social factors of the time, but our modern understanding of these events depends wholly on the individuals who have taken the time to record them and on what they’ve recorded. Looking at the history of welding, and especially the advent of filler metals, reveals limited records at best. One thing, however, is certain: the advancement of technologies is often so closely linked to the demand for industrial progress as to be indiscernible.
A Filler Metal History
Welding can be traced back as far as the Bronze Age, and 1800 marked the first instance of an arc being transferred between two carbon electrodes, a feat accomplished by Sir Humphry Davy. Yet it wasn’t until 1890 that the first appearance of filler metals as we know them in the United States was recorded (Ref. 1 and 2).
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At this time, records show that C.L. Coffin of Detroit patented his arc welding process, the first in the U.S. to use a metal electrode. In Coffin’s process, the metal was transferred across the arc into a joint, creating what we know as the weld, and also paving the way for the invention of other filler metals and welding processes (Ref. 1 and 2).
On a different continent, similar electrode inventions were also taking place around the same time. In 1885, in Russia, Nikolai N. Bernardo patented a process of carbon arc welding, using what he called an ‘electrogefest,’ or a carbon electrode, while N.G. Slavianoff cast metal he transferred via an arc into a mold (Ref. 3).
Around 1900 the first notable advancement in the development of stick electrodes occurred. In 1908, Oscar Kjellberg of ESAB patented an electrode coated with carbonates and silicates that protected the weld puddle from the atmosphere (Ref. 3).
According to records in England, between 1909 and 1912, a gentleman named A.P. Strohmenger added his own advancements to the stick electrode, developing ones that were coated in materials ranging from asbestos yarn to clay and lime, all in an effort to provide a more stable arc. He received a U.S. patent for an electrode with a covering that contained sodium silicate, which eliminated weld contaminants (Ref. 1 and 2).
Following these patents a flurry of welding advancements occurred, many of which were linked directly to the high demand for weapons and armaments during World War I. Others followed in the 1920s, including P.O. Nobel’s introduction of direct current automatic welding. In this process, he used voltage to regulate wire feed speed of the bare solid welding wire (Ref. 1 and 2).
Other notable events during this period include the development of stick electrodes for welding mild steel, and copper alloy rods, as well as high carbon electrodes. Heavy-coated electrodes, first introduced by the A.O. Smith Company in 1927 became common, and were also produced later by the Lincoln Electric® Company (Ref. 1 and 2).
Also in the 1920s, H.M. Hobart and P.K. Devers began a welding experiment using a concentric nozzle through which they fed a welding wire, an idea that would set the stage for the gas metal arc welding (GMAW) as we now know it. Notably, the GMAW process was not perfected until 1948 at the Battelle Memorial Institute (Ref. 1 and 2).
In the 1950s and 1960s, further advancements in GMAW and its continuously fed welding wire were developed when CO2 was determined to be not only an adequate, but apt addition to the welding process (Ref. 1 and 2).
First, Lyubavskii and Novoshilov combined a large diameter solid welding wire with CO2 for welding on steel in 1953. Five years later, thinner wire emerged and was used with CO2 shielding gas in a process that came to be known generically as ‘Micro-Wire.’ (Ref. 1 and 2) In fact, around that time Hobart Brothers Company marketed Micro-Wire systems that included this thin wire along with a wire feeder, power source and gas tank. Micro-Wire worked well on thinner gauge materials (Ref. 4).
With the introduction of welding with CO2 shielding gas came other filler metal inventions, notably the precursors to today’s flux-cored wire. Attributed to Arthur Bernard in 1954, who dubbed the process Dualshield®, FCAW began with the creation of a flux-cored wire, similar to those manufactured today. The flux itself generated shielding gas, but an external supply of CO2 was still necessary to protect the weld puddle. The development of a self-shielded welding wire in 1959 would eliminate the need for an external shielding gas supply and it was therefore called Innershield® (Ref. 1 and 2).
After the advent of FCAW and flux-cored wire, filler metal advancements (both stick electrode and wire) slowed, and few records exist that measure significant milestones in arc welding. However, knowing what we do about today’s welding processes and filler metals, it is certain that the period between the 1960s and today have not been idle.
The 1970s saw the introduction of all-position flux-cored wires (1972), along with the development of metal-cored wires (1973)—tubular wires comprised of a metal sheath and a core of powdered materials. Both types of wires allowed for the addition of alloys to match a wider variety of base materials and help higher productivity welds, features that continued to be refined during the 1980s and 90s.
Today, manufacturers have the ability to produce stick electrodes, solid wires, and flux-cored and metal-cored wires in higher quantities than ever before. Engineers are also devising ever more advanced filler metal formulas to improve arc performance and weld quality on even the most exotic of materials. And if our vague history of welding and filler metals has shown anything, it is this: such advancements are inevitable and will likely continue.
Hobart Brothers' Own History
After multiple business ventures (most of which still exist today), C.C. Hobart, his wife Lou Ella, and their three sons—Edward, Charles and William—incorporated Hobart Brothers Company (1917). This year marks the company’s 90th anniversary .
Since its inception, Hobart Brothers Company has contributed meaningfully to the welding industry, from the production of its first arc welder in 1925 to the development of a welding rectifier in 1952, and the eventual (and continuing) production of filler metals.
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With the help of their parents, Ella and C.C., the three Hobart |
Notably, 1930 marked the establishment of a training school, which began as a division of the company and still operates today as a separate, non-profit entity: the Hobart Institute of Welding Technology .
By the 1940s, Hobart Brothers’ Company turned to the production of stick electrodes and offered 18 varieties, including a carbon rod, coated electrodes, and two electrodes for AC welders. In 1956 it began producing solid welding wires and in 1962, flux-cored wires.
The company added metal-cored wires to its repertoire upon the purchase of Tri-Mark and Corex in 1989. It then acquired McKay, a leading hard surfacing and stainless steel filler metal brand in 1993, and it still offers the Hobart brand of filler metals. Its welding equipment is now offered under the name, Hobart Welding Products.
Works Cited: Ref. 1: “Historical Development of Welding,” from Modern Welding Technology by Howard B. Cary and Scott C. Helzer, PhD. 2005. Pearson Education, Inc., Upper Saddle River, New Jersey. Ref. 2: “A History of Welding.” www.welding.com/history_of_welding.shtml. Welding.com [Web site] Ref. 3: “A History of Welding from Hephaestus to Apollo,” by Mark Sapp. www.weldinghistory.org/2007_history/welding/index.html. Weldinghistory.org [Web site] Ref. 4: The Industrial Hobarts: One Family’s Story Through the American Century, by Peter C. Hobart and Michael W. Williams. 2004. The Donning Company Publishers, Virginia Beach, VA.
Works or Resources Consulted: Hobart Institute of Welding Technology, Troy, Ohio.“About AWS: As Time Goes By.” American Welding Society, Miami, Florida. http://www.aws.org/w/a/about/index.html. AWS.org [Web site]