Page 18 - Demo

Issue 143 August 2024 PCMI Journal 18
PCM of Difficult-to-Etch Metals and Alloys: Nickel- and Cobalt-Based Superalloys
Emeritus Professor David Allen, Cranfield University
compositions of the alloys to be within a certain specification range (even if not
identical).
Table 2. Universal Number Specification Designations
UNS Designation General description
N00001-N99999 Nickel and nickel alloys
R00001-R99999 Refractory metals and alloys
R3XXXX Cobalt alloys
Early superalloy development
After a short early career as a teacher, Elwood Haynes worked in the oil
and gas industry. It was during this time that he developed his ideas for a
“horseless carriage.” Haynes moved to Kokomo, IN in December 1892 and found
time to work on his horseless carriage. His first automobile, “Pioneer” was
successfully tested on July 4, 1894. While there is some dispute as to whom the
honour of the first automobile in the United States should go, the success of
Pioneer led Haynes to form a company, which produced high-end automobiles
through the mid-1920s.
Haynes was in search of a material that would resist tarnishing and be suitable
for cutlery. After several years of unsuccessful experiments, he developed viable
alloys in 1907 and was awarded two patents: one for a nickel-chromium alloy
and one for a cobalt-chromium alloy, both to be used as cutting tools for
automotive engine components. Then in September 1912, the United States
Patent Office informed Haynes that he would also be granted two patents for
new cobalt-chromium-tungsten-molybdenum alloys. It was this event that
resulted in the formation of the Haynes Stellite Works in Kokomo. In the early
1920s, Haynes’ company was bought by Union Carbide.
At Union Carbide’s R&D facilities at Niagara Falls, NY, research was also being
conducted into nickel-molybdenum alloys for corrosion resistance. This marked
the origins of the nickel-base superalloy industry. A patent was obtained for a
nickel-molybdenum alloy composition range in 1921, which eventually led to the
invention of Hastelloy A alloy and, two years later, Hastelloy B alloy. The unique
composition of Hastelloy B is still being manufactured today. In 1926, Hastelloy C
alloy was invented. The fifth generation of this alloy, Hastelloy C-2000 alloy, is
still being supplied to the chemical process industry today.