Effective Technological Process of Crystallization of Turning Rollers' Massive Castings: Development and Analysis

Abstract

Abstract: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.

Hardening of Thin-Walled Knives by Nanostructured Coating and Their Operating Resistance

“…The developed method using a new approach to assessing the phase distribution includes an optical-mathematical method for describing structural changes, the degree of its heterogeneity [5,6].…”

Optical-Mathematical Analysis of Structuration Modeling of Hardened Surfaces of Piston Rings during Operation

“…После испытаний была выполнена оптико-математическая оценка формируемых фаз по базовой методике в соответствии с ранее проведенными исследованиями [8][9][10][11][12][13][14][15][16]. Для этого была дополнительно предложена специальная компьютерная программа на основе интервалов относительной нейтральности абсолютной величины лапласианов и дивергенций, расчет которых производили по пятиточечной разностной схеме, представленной на рис.…”

“…Такой метод позволяет выявить зависимости между параметрами эксплуатации и формируемой структурой в контактирующих поверхностях колец, которые могут быть оценены по аппроксимации цифровых изображений изделий. Данный способ позволяет также оценить степень и характер формируемых напряжений и локально выявить зону их концентрации [8][9][10][11][12][13][14][15][16] по изменению структурной анизотропии.…”

Synthesis of the structure of functional systems of conversion class with a portional supply of initial products

“…Efficiency of such production structures is improved not by optimizing control processes but by creating and introduction of new technologies [18]. In cases where limited control capabilities are still being realized, mechanisms of not optimal but extreme control are embedded [19].…”