On osmondite nature
- 1 — Saint-Petersburg Mining University
- 2 — Geotechnical Engineers and Scientists
Abstract
The uniqueness of iron is not only that it is one of the most common elements, and the production of its derivative (steel) «exceeds the production of other metals by 14 times», not only in its polymorphism, but also in the following: «conversion of BCC α-Fe (К = 8) into a denser FCC γ-modification (K = 12) with heating is quite unusual and along with the thermodynamic interpretation requires a special physical explanation, especially in connection with the fact that it lies at the basis of the metal science and the thermal treatment of iron alloys» ( V.K.Grigorovich). «Unusual» iron is also confirmed by the fact that the hardness of Fe at 440 °С is 1.15 times higher than at 20 °С. Other metals of this unique quality do not – as the temperature rises, the hardness decreases. Only manganese with a tetragonal lattice exhibits a hardness maximum at 650-750 °C; a maximum hardness is observed near the α D β transformation of manganese. The absolute maximum of hardness at 440 °C for iron allows (by analogy) to assume a transformation in iron at this temperature. Especially note: at the temperature of unconditional a→g → </s> transformation (910 °C) there is an absolute minimum of hardness. A curious situation arose around the temperature interval 400-500 °С. M.V.Belous and his co-authors simply do not notice it in the classification of four transformations during drawing back process, although back in 1925 P.Oberghoffer, basing on a minimum at 400-500 °C of the thermoelectric power of the iron-platinum pair, wrote: «Whether we are here dealing with further transformations in pure iron, should be investigated in new detailed studies». Based on the maximum etchability value, acceleration of the graphitization of steels, the maximum corrosion rate of gray cast iron, anomalies in the temperature dependences of the physical and mechanical properties, changes in the solubility of cementite, the maximum lattice parameter, the extremum on the resistance curve of the pure iron deposit, the conversion in iron at ~ 450 °C is justified.
References
- Белоус М.В. Превращения при отпуске стали / М.В.Белоус, В.Т.Черепин, М.А.Васильев. М.: Металлургия, 1973. 232 с.
- Григорович В.К. Электронное строение и термодинамика сплавов железа. М.: Наука, 1970. 292 с.
- Гриднев В.Н. Электронно-микроскопическое исследование структуры электроотпущенной стали / В.Н.Гриднев, Ю.Н.Петров // Вопросы физики металлов и металловедения. 1964. № 19. С. 79-86.
- Гудремон Э. Специальные стали. В 2-х т. Т. 1. М.: Металлургиздат, 1959. 952 с.
- Курдюмов Г.В. Превращение в железе и стали / Г.В.Курдюмов, Л.М.Утевский, Р.И.Энтин. М.: Наука, 1970. 236 с.
- Лившиц Б.Г. Физические свойства сплавов. М.: Металлургиздат, 1946. 320 с.
- Лысак Л.И. Изменение тонкой кристаллической структуры закаленной стали при отпуске // Вопросы физики металлов и металловедения. 1952. № 3. С. 28-40.
- Перлит в углеродистых сталях / В.М.Счастливцев, Д.А.Мирзаев, И.Л.Яковлева, К.Ю.Окишев, Т.И.Табатчикова, Ю.В.Хлебникова. Екатеринбург: УрО РАН, 2006. 311 с.
- Стародубов К.Ф. Изменение пластических свойств стали при отпуске / К.Ф.Стародубов, В.К.Бабич. Днепропетровск: Укр НТО Чермет, 1957. 31 с.
- Стародубов К.Ф. О природе процессов, протекающих при отпуске закаленной стали в интервале температур 350-550 оС // Научн. докл. высш. школы. Металлургия. 1958. № 31. С. 266-268.
- Тавадзе Ф.Н. Влияние термической обработки на коррозионную стойкость чугуна / Ф.Н.Тавадзе, Б.Е.Галинкин // Труды Грузинского политехнического ин-та. 1957. № 3 (51). С. 120-126.
- Устиновщиков Ю.И. Вторичное твердение конструкционных сталей. М.: Металлургия. 1982. 128 с.
- Физическое металловедение / Я.С.Уманский, Б.Н.Финкельштейн, М.Е.Блантер, С.Т.Кишкин. М.: Металлургиздат. 1955. 724 с.
- Шахназаров К.Ю. 430±30 оС – узловая (критическая) температура железа и углеродистой стали / К.Ю.Шахназаров, А.Ю.Шахназаров // Металловедение и термическая обработка металлов. 2001. № 11. С. 24-25.
- Шахназаров Ю.В. Твердость и ширина рентгеновской линии углеродистых и среднелегированных сталей после отпуска при 20-670 оС / Ю.В.Шахназаров, В.Д.Андреева // Мат. сем. «Материаловедение, пластическая и термическая обработка»; СПбГПУ. СПб, 2001. С. 34-36.
- Шахназаров К.Ю. Аномалии физико-механических свойств железа как следствие превращений в нем при ~650, ~450 и ~200 С // Вестник Магнитогорского государственного технического университета им. Г.И.Носова. 2017. Т. 15. № 1. С. 70-78. DOI: 10.18503/1995-2732-2017-15-1-70-78.