The Fe-C diagram – History of its evolution

The evolution of concepts and methods of physical and chemical science that contributed to the formation of the Fe-C diagram during the previous centuries is considered. Despite the classical knowledge, there are still differences in the representation of the Fe-C diagram by scientists from different countries, in particular, the data of scientists from Germany, Poland, Ukraine, the USA, and Australia are somewhat mismatched. The authors tried to understand the reasons for this discrepancy. To conduct the research, general scientific methods of cognition were used: comparative analysis and synthesis, as well as a chronological one. It is claimed that the first studies of carbon content in steel were carried out in 1802. Further research development began in 1827–1829 when it was established that graphite is pure carbon. It is emphasized that further studies of carbon content in steel and cast iron are connected with attempts to create the first graphs of dependence on content and temperature. This, in turn, contributed to the development of the industrial revolution. It is believed that the first complete diagram was presented in 1897 by Roberts-Austen. Later, with the use of X-ray methods and microscopy, the Fe-C diagram gradually took on a new form. At the beginning of the 20th century, scientists actively proposed their phase diagrams. Studies conducted by scientists of different countries during 1909–1911 gained a consolidation, which was produced at the 6th Congress of the International Association for testing materials meeting into the unification of the names of phase transformations. Further research until the beginning of the Second World War was aimed at the creation of “pure” steel, that is, without harmful impurities, and clarifying the transformation temperatures. The period of the Great Depression in the USA and the war in Europe did not contribute to scientific research. At the same time, for the mass production of steel and cast iron, errors in critical points of a few degrees did not have a significant impact, that is, refining the temperatures of phase transformations were not considered appropriate. Today’s trend in scientific research is aimed at solving environmental problems caused by the industrial revolution.