Réaumur Discovers Carbon’s Role in Hardening Steel

René-Antoine Ferchault de Réaumur wrote a treatise on transforming iron ore into steel, revolutionizing metallurgy in France. Réaumur’s recommendations and analysis not only made it possible for France to produce steel for itself rather than importing the metal but also helped pave the way for the Industrial Revolution.

Summary of Event

Modern industry Industrial Revolution;France began to emerge in Europe in the eighteenth century, and one of the major requirements for its full emergence was a plentiful supply of raw materials from which tools and machinery Machines;steel manufacture could be manufactured. Pure iron was too soft for such a purpose, but steel was ideally suited to industrial applications. Steel is composed mostly of iron, but it also contains less than 2 percent carbon, Carbon and steel production and the carbon makes it much harder and more resilient than iron alone. The French scientist and engineer René-Antoine Ferchault de Réaumur determined that carbon had this effect upon iron, making it possible to manufacture steel on a mass scale. [kw]Réaumur Discovers Carbon’s Role in Hardening Steel (1722)
[kw]Steel, Réaumur Discovers Carbon’s Role in Hardening (1722)
[kw]Hardening Steel, Réaumur Discovers Carbon’s Role in (1722)
[kw]Role in Hardening Steel, Réaumur Discovers Carbon’s (1722)
[kw]Carbon’s Role in Hardening Steel, Réaumur Discovers (1722)
[kw]Discovers Carbon’s Role in Hardening Steel, Réaumur (1722)
Steel production
[g]France;1722: Réaumur Discovers Carbon’s Role in Hardening Steel[0610]
[c]Chemistry;1722: Réaumur Discovers Carbon’s Role in Hardening Steel[0610]
[c]Engineering;1722: Réaumur Discovers Carbon’s Role in Hardening Steel[0610]
[c]Science and technology;1722: Réaumur Discovers Carbon’s Role in Hardening Steel[0610]
Réaumur, René-Antoine Ferchault de
Louis XV
Colbert, Jean-Baptiste

Réaumur came to Paris at the age of twenty. Already educated in mathematics and civil law, he continued and expanded his studies, focusing on mathematics and physics, with Pierre Varignon. Through the social contacts of a cousin, he gained the acquaintance of the president of of the Académie des Sciences, where he became a student of geometry on March 12, 1708. Only two months after being admitted, he presented his first paper in mathematics, impressing the members sufficiently that three years later he was admitted as a permanent member in mechanics.

While still a student, Réaumur was asked to produce a survey of all the arts, handicrafts, and trades of France, a project envisioned by Jean-Baptiste Colbert in the previous century but never completed. Taking up the task with the intellectual zeal of a scientist, Réaumur went far beyond cataloging the productive trades of his nation. Surveying France’s goldsmiths prompted him to investigate the country’s auriferous (gold-bearing) rivers; listing the artists who worked in turquoise led him to study the mineralogy and mining that supported their trade and to analyze the fossil beds of France. In addition to describing the techniques and distribution of French craftspeople, Réaumur’s Description des divers arts et métiers de France (1710; description of the diverse arts and occupations of France) explicated the geographic and scientific factors that made their crafts possible.

In the next decade, Réaumur became obsessed with metal production, perhaps because he had inherited a steel mill on the southwest coast of France. In his survey of crafts, Réaumur had noticed that France lagged behind its neighbors in the production of steel. As a result, the French manufacturing industry depended on imported steel from Germany. Characteristically, his discussions with metalworkers led him to a scientific investigation of the principles behind their craft, in this case the chemistry of iron ore its smelted products. Iron had never before been studied chemically. Réaumur examined the different chemical compositions of iron when smelted from different types of ores and accurately surmised that the proportion of carbon in the smelted product was the primary factor determining the product’s ductility or lack of ductility.

With patience and accuracy, Réaumur tested cast iron, steel, and wrought iron, and he was the first scientist to use a microscope to observe their different crystalline structures. In 1722, he published the results of twelve years of intense study in L’Art de convertir le fer forgé (Memoirs on Steel and Iron, Memoirs on Steel and Iron (Réaumur) 1956). His treatise discussed the methods for producing cast iron, wrought iron, and steel. It indicated which minerals should be added to or eliminated from steel to enhance its ductility and resistance. It introduced a method Réaumur had discovered for producing steel by adding iron oxides to melted iron, and it recommended cleaning and polishing steel stock before rolling the stock into sheets. King Louis XV was sufficiently impressed by the work that he awarded Réaumur a £12,000 pension, which Réaumur generously forwarded to the Académie des Sciences to further scientific research.


While steel was already being produced when Réaumur published his treatise, the chemical principles underlying its production were unknown. Réaumur’s work, by revealing those principles, revolutionized iron and steel production. His practical recommendations made it possible for the French to produce their own steel in much greater quantities, greatly reducing their dependence on foreign imports. It was his theoretical scientific analysis, however, that enabled future metallurgists and engineers to refine manufacturing techniques, ultimately superseding the methods Réaumur discovered. Thus, his work helped to establish the general usefulness of scientific analysis for developing modern industrial techniques. It was one of many developments in the eighteenth century that made possible the Industrial Revolution.

Further Reading

  • Bunch, Bryan, with Alexander Hellemans. The History of Science and Technology: A Browser’s Guide to the Great Discoveries, Inventions, and the People Who Made Them, from the Dawn of Time to Today. Boston: Houghton Mifflin, 2004. Provides a wealth of information, presented in lucid fashion, on the history of science and technology.
  • Freytag, Dean A. The History, Making, and Modeling of Steel. Milwaukee, Wis.: William K. Walthers, 1996. A useful overview of the changes in the processes of steel making through time.
  • Gribbin, John. The Scientists: A History of Science Told Through the Lives of Its Greatest Inventors. New York: Random House, 2002. Describes the evolution of science in the last five hundred years.
  • Tylecote, R. F. A History of Metallurgy. 2d ed. Boston: Maney, 2002. Examines the development of smelting techniques and the uses of metals from the Neolitic period until now.

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