Effective Technological Process of Crystallization of Turning Rollers' Massive Castings: Development and Analysis
| Autor: | T. S. Skoblo, Efim Belkin, Sidashenko Aleksandr I, Oksana Klochko |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
010302 applied physics
Austenite Materials science Cementite Metallurgy 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Casting Carbide law.invention Stress (mechanics) chemistry.chemical_compound chemistry law Residual stress 0103 physical sciences Crystallization Dislocation 0210 nano-technology |
| Zdroj: | International Journal of Mineral Processing and Extractive Metallurgy. 2:34 |
| ISSN: | 2575-1840 |
| DOI: | 10.11648/j.ijmpem.20170203.12 |
| Popis: | The paper describes a new method of maximum reducing residual stresses and stabilization of the structure, hardness of the working layer of massive sheet rolls from alloyed cast irons during their crystallization due to controlled decomposition of retained austenite. It is achieved by programmable preheating of the metal form to the temperature of magnetic transformation of doped cementite or special carbides of the castings (depending on the material being processed); meanwhile it is provided an optimum cooling rate with an exposure of up to 6 hours in this interval and maximizes decomposition of retained austenite, minimizes stresses in the working layer. This casting technology is also accompanied by appropriate structural changes. Inhomogeneity of the dislocation structure is noted in various constituent phases. Polygonization and fragmentation along dislocation walls are revealed in the carbide phase. To evaluate the occurring processes, a new method of optical and mathematical description of the phases being formed is used. As a criterion describing the changes in the dislocation structure, we use the parameter - a power dissipation power function. The proposed casting technology for rolls is particularly effective when the proportion of the carbide phase is at least 25%. In this case, the heat treatment of the rolls to relieve stress does not change the stably achieved properties. It is shown that the quality control on the stability of the achieved indicators can be carried out by the coercive force and the level of hardness. |
| Databáze: | OpenAIRE |
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