Chernov, Dmitri Konstantinovich

(b. St Petersburg, Russia, 1 November 1839; d. Yalta, U. S. S.R., 2 January 1921),

metallurgy

The son of a Physcian, Chernov graduated from the St. Petersburg Practical Technological Institute in 1858 and remained there until 1866 as a teacher of mathematics and assitant to the head of the scientific and technical library. From 1866 to 1880 he worked in the Obukhovsky steel casting plant in St. Petersburg, first as an engineer in the forging shop and then as metallurgical assistant to the head of the plant. Chernov prospected for deposits of rock salt in the Donets Basin from 1880 to 1884, returning in the latter year to St. Petersburg. From 1889 he was professor of metallurgy at the Mikhailovsky Artillery Academy in St. Petersburg.

As a result of his study of the reasons for waste in the manufacture of gun forgings, and also of his penetrating analysis of the work of P. P. Anosov, P. M. Obukhov, A. S. Lavrov, and N. V. Kalakutsky (who were concerned with the smelting, casting, and forging of steel ingots), in 1866–1868 Chernov proposed that the structure and properties of steel depend on its treatment by mechanical means (pressure) and heat. He discovered the critical temperatures at which phase transformations alter the essential structure and properties of the metal as the result of its being heated or cooled in the solid state. Introduced onto a thermometric scale, these temperatures formed a series of points called “Chernov points,” the most important being the critical points a and b, associated with the polymorphic transformation of iron. Point a was defined by Chernov as the temperature below which steel does not harden independently of the speed of cooling.

This point (now designated A ₁) corresponds to the temperature of the eutechtoid transformation steel. The next critical point, b (now designated A₃), is defined as the temperature at which, in the opinion of a majority of scientists, the dissolution of ferrite in austenite ceases during the heating of steel. Chernov stated that to obtain the most desirable fine-grained structure, steel should be heated to point b or higher and then cooled. Chernov’s critical point depend on the chemical composition of the steel, especially on its carbon content. He graphically reprecritical points by making the first rough sketch of the most important lines of the “iron-carbon’ state” diagram. At the end of the nineteenth and the beginning of the twentieth centuries many metallurgists in various countries were working on the development and improvement of this classic diagram.

Chernov presented the results of his remarkable research in April and May 1868 at the sessions of the Russian Technical Society and published them in the same year. In 1876 this work was published in England, and a year later in France. It formed the scientific basis for contemporary metallurgy and the processes for heat treatment of metals. The French metallurgist Floris Osmond, in developing Chernov’s work, discoverd the precise significance of the critical points(1886) by using the thermoelectric pyrometer, invented in the same year by Henry Le Chatelier. Osmond introduced the desgnation of the critical points by the capital letter a with its corrresponding indices, and the description of the character of the microstructural changes that occur in the transition through the critical points. At the beginning of the 1920’s the transformations produced in steel by the action of heating and cooling also received experimental confirmation from radiographic methods.

In his next scientific work, “Issledovania, otnosyashchiuesya do strucktury litykh stalnykh bolvanok” (“Investigations Relating to the Structure of Cast Steel Ingots”), Chernov presented coherent theory of the crystallization of steel ingots. He investigated in detail the origin and growth of crystals, constructed a diagram of the structural zones of ingots, developed a theory of successive crystallization, thoroughly studied the defects of cast steel, and suggested effective measures to overcome them. This research greatly aided the transformation of metallurgy from a practical art into a theoretically based scientific discipline.

Of great importance for the progress of steel metallurgy was Chernov’s work on expanding the use of metallurgical processes and on improvements in the techniques of production. He confirmed the importance of the complete deoxidation of steel during smelting and the advisability of using complex deoxidizers, and he recommended a system of measures for obtaining dense forms of the metal free of air bubbles. He advanced the idea of stirring the metal during crystallization, proposing a rotating crucible for this purpose. Chernov did much to improve the converter method of producing cast steel. In 1872 he proposed warming liquid low-silicon iron, previouslly considered unprofitable for the Bessemer process, in a cupola furnace before it was aerated in the converter. Later this method was widely used in both Russian and foreign factories. Chernov was he first too use the spectroscope to determine when to stop the Bessemer process. He warmly suported Akerman’s proposal to use oxygen-enriched air for aerating liquied iron in the converter. He also worked on the problem of obtaining steel directly from ore, bypassing the problem of obtaining steel directly from ore, bypassing the blast furance. Chernov was responsible for much important research in artillery production: the obtaining of high-quality barrels on weapons; steel-armored projectiles; and research on the corrosion of the bores of weapons, resulting from the action of gases released when the weapon is fired. He also wrote a number of works on mathematiscs and aviation.

Chernov was the founder of an important school of metallurgists and metallurgical scientists. He had many pupils and followers-including A. Baykov, N. Kurnakov, A. Rzheshotarsky, and N. Gudsov-who developed his ideas and made their own contributions to metallurgy. Among Chervo’s foreign followers were Hein, F. Osmond, and A. Portevin. Chernov was elected honorary president of the Russian Metallurgical Society, honorary vice-president of the English Institute of Iron and Steel, honorary member of the American Institute of Iron and Steel, honorary member of the American Institute of Mining Enginers, honorary corresponding member of the Royal Society of Arts (London), and member of many other scientific organizations.

BIBLIOGRAPHY

1. Original Works. Chernov’s basic works are"Kritichesky obzor statey Lavrova i Kalakutskogo o stali i stalnykh orudiakh i sobstvennye D. K. Chernova issledovania po etomu zhe predmetu” (“A Critical Survey of the Articles of Lavrov and Kalakutsky on Steel and Steel Weapons and D. K. Chernov’s Own Research on the Same Subject”), in Zapiski Russkogo tekhnicheskogo obshchestva (“Notes of the Russian Technical Society”) (1868), no. 7, 339–440; V. Anderson, trans., in Enginerring (1876), issues of 7 and 14 July, and M. Tchernoff, trans., Note sur la constitution et le travail de l’acier (Paris, 1877); “Issledovania, otnosyashchiesya do struktury litykh stalnykh bolvanok” (“Investigations Relating to the Structure of Cast Steel Ingots”), ibid. (1879), no. 1, 1–24; staleliteynoe delo (“The Cast Stell Business"; St Petersburg, 1898); and “Materialy dlya izuchenia bessemerovania” (Material for the Study of the Bessemer Process”), ibid. (1915), no. 1, 55–90. These and a number of other works by Chernov are included in the collection D. K. Chernov i nauka o metallakh (“D. k. Chernov and the Science of Metals"; Leningrad- Moscow, 1950).

II. Secondary Literature. On Chernov or his work see I. P. Bardin, “Osnovopolozhinik sovremennogo metallovedenia, vydayushchysya russky ucheny-metallurg D. k. Cherno” (“The Founder of Contemporary Metal Science, the Distinguished Russian Scientist and Metallurgist D. K. Chernov”), in Lzvestiya Akademii nauk SSSR. Otdelenie tekhnicheskih nauk(1951), no. 6, 900–906; A. A. Bochvar, “Raboty D. K. Chernova v oblasti metallovedenia i ikh znachenie v sovremennoy nauke” (“The Works of D. K. Chernov in the Field of Metallurgy and Their Significance in Contemporary Science”), in lzvestiya Akademii nauk SSSR Metally (1969), on. 1, pp. 3–13; A. S. Fedorov, “D.K. Chernov. K stoletiyu so dnya rozhdenia” (“D. K. Cherno. K stoletiyu of His Birth”), in lzvestiya Akademii nauk SSSR. Otdelenie tekhnicheskikh nauk (1939), no. 9, 95–108; and “Yarkaya stranitsa v nauke o metalle. K 100-letiyu otkytia D. K. Chernovym fazovykh prevrashcheny vstali” (“A Bright Page in the Science of Metal. Ont the 100 th Anniversary of the Discovery by D. K. Chernov of Phase Transformation in Steel”), in Priroda (1968), no. 4, 109–115; A. F. Golovin, D. K. Chernov-osnovopolozhnik nauki o metallakh (“D. K. Chernov- Founder of the Science of Metals”), no. 5 in the series Trudy po Istorii Tekhniki (Moscow, 1954), 39–57; and “K stoletiyu otkyrtia D. K. Chernovym polifmorfnykh prevrashcheny v stali, 1868–1968”(“On the 100th Anniversary of the Discovery by 1868–1968”), in Metallovedenie i termicheskaya obrabotka metallov (1968), no. 5, 2–8; G. Z. Nesselshtraus, “Zhizsn i deyatelnost D. K. Chernova-osnovatelya metallografii” (“The Life and Work of D. K. Chernov, Founder of Metallography”), in D. K. Chernov i nauka o metallakh (see above), 7–59; and A. m. Samarin, “D. K. Chernov i sovremennoe stalefarenie’ (“D. K. Chernov and Contemporrary Steel Foundry”), in Lzvestiya Akademi nauk SSSR. Metally (1969), no. 1, 77–82.

A. S. Fedorov