Structure formation of high-chromium cast irons in the temperature range of the magnetic transformation of carbide phasesстатья из журнала
Аннотация: A new comprehensive approach has been developed to characterize the structure formation of high-chromium cast iron in the working layers of mill rolls (10 –12 tons weight) within the hot finishers. Application of our approach makes it possible to estimate the phase composition of the alloy. Such heterogeneous material is characterized by insufficient stability of properties and the absence of reliable methods for assessing structure formation. The structural features of massive castings (up to 20 tons) are revealed in the process of crystallization and operation under the temperatures of magnetic transformation of the carbide phases (magnetostriction phenomenon). The conducted studies introduce a new understanding of the phase composition of high chromium cast iron, the phase composition variability at magnetic transformation of carbide phases and decomposition of retained austenite. The variability of phases and their interconnection during casting and heat treatment are estimated. It has been shown that photographs of metallographic images do not allow one to reliably estimate the alloy phase composition, since the primary image pattern after crystallization preserves, while a partial phase decomposition with the formation of their various combinations takes place. The possibility of accurate qualitative and quantitative identification of the formed phases in the cast and heat-treated state in a multiphase heterogeneous alloy (high-chromium cast iron of large masses) is shown. A new approach to the characterization of structure formation in a multiphase alloy with the optical-mathematical method for the description of metallographic images is proposed. We show that the insufficient stability of the phase composition while casting under magnetostriction temperatures and with the proposed effective heat treatment method used is determined by the variability of structure formation with the buildup of certain bonds between the phases and decomposition of residual austenite.
Год издания: 2020
Источник: Letters on Materials
Ключевые слова: Metal Alloys Wear and Properties, Microstructure and Mechanical Properties of Steels, Surface Treatment and Coatings
Открытый доступ: bronze
Том: 10
Выпуск: 2
Страницы: 129–134