2022
Quantitative Estimation of Formation of Shrinkage Porosity by the Niyama Criterion
Author: E. S. Ivanina, V. P. Monastyrskiy, and M. Yu. Ershov.
Source: Inorganic Materials: Applied Research, 2022, Vol. 13, No. 1, pp. 100–105.
Abstract: Critical values of the Niyama criterion were determined for castings from alloy ML10 on the basis of a computational experiment. It was shown that the Niyama criterion is suitable only for qualitative evaluation of the possibility of porosity formation. One of the options of constructing an unambiguous dependence and scale of porosity by the values of the temperature gradient and solidification rate was proposed.
2020
Development of Promising Technology for Manufacturing Parts of Gas Turbine Engines
Author: Vdovin R.A.
Source: International Science and Technology Conference (FarEastСon 2020), IOP Conf. Series: Materials Science and Engineering
Abstract: This article discusses the results of the development of a promising technology for
manufacturing parts of gas turbine engines. First of all, this technology is promising due to the
use of the PoligonSoft system utilized for computer modeling of casting processes, which made
it possible to evaluate the efficiency of the gating and feeding system, as well as to predict the
appearance of casting defects (porosity and macrostructure discrepancies) and to develop a set of
measures for their detection and elimination; second of all, due to the use of rapid prototyping
which employs 3D printing of the master model, thus reducing the time and financial costs for
the preparation of technological equipment. According to preliminary estimates, the use of rapid
prototyping has reduced the cost of manufacturing 250 wax models by 15% in comparison with
the traditional technology, and also reduced time costs by an average of 5-6 months.
2017
Mechanism of Competitive Grain Growth in a Curvilinear Channel of Crystal-Sorter during the Orientational Solidification of Nickel-Based Heat-Resistant Alloy
Authors: Monastyrskiy V.P., Pozdnyakov A.N., Ershov M.Yu., Monastyrskiy A.V.
Source: Physics of Metals and Metallography, 2017, Vol. 118, No. 7, pp. 652–658. © Pleiades Publishing, Ltd., 2017.
Abstract: Using numerical simulation in the ProCAST program complex, the conditions of the solidification of heat-resistant nickel alloy in curvilinear channels of a ceramic mold have been investigated. It has been shown that, in practically important cases, the vector of the temperature gradient is oriented along the axis of the curvilinear channel. In a spiral crystal selector, a cyclic change in the preferred direction of growth occurs because of the cyclic change in the direction of the vector of the temperature gradient. The fact that the vector of the temperature gradient is almost always directed along the axis of the curvilinear channel makes it possible to govern the orientation of the vector of the temperature gradient in space and, therefore, to obtain a grain with the preferred crystallographic orientation. Based on the results of this investigation, a method of the grain selection with a desired azimuthal orientation is proposed.
Source: Physics of Metals and Metallography, 2017, Vol. 118, No. 7, pp. 652–658. © Pleiades Publishing, Ltd., 2017.
Abstract: Using numerical simulation in the ProCAST program complex, the conditions of the solidification of heat-resistant nickel alloy in curvilinear channels of a ceramic mold have been investigated. It has been shown that, in practically important cases, the vector of the temperature gradient is oriented along the axis of the curvilinear channel. In a spiral crystal selector, a cyclic change in the preferred direction of growth occurs because of the cyclic change in the direction of the vector of the temperature gradient. The fact that the vector of the temperature gradient is almost always directed along the axis of the curvilinear channel makes it possible to govern the orientation of the vector of the temperature gradient in space and, therefore, to obtain a grain with the preferred crystallographic orientation. Based on the results of this investigation, a method of the grain selection with a desired azimuthal orientation is proposed.
2016
Production of Railcar Cast Wheels in Sand Molds
Author: Broytman O.A., Orlova A.M., Savushkin R.A., Bezobrazov Yu.A.
Source: Proceedings of the 18th Int. Wheelset Congress 7-10 November 2016, Chengdu, China
Abstract: Present-day operation conditions for railcar wheels involve high axle loads and velocities which lead to strict requirements to their mechanical properties characteristics and resistance to cyclic stresses. Complying the requirements come from selection of proper wheel alloy chemical composition and production method of the part. The method must guarantee absence of critical defects which may be a cause of failure for the wheel body. The present work investigates manufacturability of wheels with most economically reasonable way – by metal pouring into sand temporary mold. This method favorably compares with known cast wheels production practices which demand special maintenance for permanent and semi-permanent molds made of materials with significant differences in their heat removing abilities. The work pays closer attention to development of optimal wheel steel chemical composition including vanadium microalloying, melting conditions and selection of proper final heat treatment regimes. The up-to-date computer modeling tools and techniques were utilized during the work process, appropriate experimental data were collected and pilot batches produced. The work shows that selection of rational conditions for pouring and feeding of castings combined with optimal steel composition allows wheels production in temporary sand molds in such a way that mechanical and performance characteristics of final parts are non-inferior to whose which are typical for parts produced by traditional known methods.
2015
Computer Modelling of Castings Quality with Taking Into Account the Differentiation of Structure-Dependent Cores and Molds Material Properties
Author: Broytman O.A., Babkov D.S., Ioffe M.A.
Source: Machines, Technologies, Materials. 2015. № 4. С. 15.
Abstract: Typical casting simulation procedure doesn’t consider exact cores and molds material properties as a primary factor. Sometimes mold is considered as an isotropic body characterized with constant averaged thermophysical and other properties. On the other hand there are a lot of practically collected data confirming the fact that input of exact non-uniformly distributed thermophysical mold properties during casting simulation may seriously improve the prognosis of casting quality. The present work is dedicated to interconnections between molds compacting conditions and castings quality. It has been proposed to carry out the computer modeling of compacting process for further use of the calculation results as a part of input for casting simulation software.
Simulation of Competitive Grain Growth upon the Directional Solidification of a Ni-Base Superalloy
Authors: Pozdniakov A.N., Monastyrskiy V.P., Ershov M.Yu., Monastyrskiy A.V.
Source: The Physics of Metals and Metallography, 2015, Vol. 116, No. 1, pp. 63–71. © Pleiades Publishing, Ltd., 2015.
Abstract: Using the numerical simulation in the CA[1]FE module of the ProCAST simulation program, a systematic investigation of competitive growth of grains in a thin plate has been performed over a wide range of values of the temperature gradient and solidification rate. It has been established that the result of the simulation in the case of converging grains depends on the only parameter, i.e., the ratio of the value of the overgrowth of the grain with the preferred orientation to the size of the cell of the computational grid. Thus, the size of the cell is an important adjusting parameter of the model and must be coordinated with the parameters of the dendritic structure under given growth conditions. The grain with the preferred orientation always displaces neighboring diverging grains. The converging grains are eliminated if their deviation from the vector of the temperature gradient exceeds 20°. At the smaller angles of deviation, the result of the competitive growth depends on the size of the computational cell and varies from their joint growth (at the cell size of 5 μm) to the displacement of grains with the preferred orientation (at the cell size of 20 μm). However, all of the results of the simulation agree with the experimental data available in the literature. For the efficient selection of grains with the preferred orientation, regimes with a low temperature gradient and high growth rate are favorable.
Source: The Physics of Metals and Metallography, 2015, Vol. 116, No. 1, pp. 63–71. © Pleiades Publishing, Ltd., 2015.
Abstract: Using the numerical simulation in the CA[1]FE module of the ProCAST simulation program, a systematic investigation of competitive growth of grains in a thin plate has been performed over a wide range of values of the temperature gradient and solidification rate. It has been established that the result of the simulation in the case of converging grains depends on the only parameter, i.e., the ratio of the value of the overgrowth of the grain with the preferred orientation to the size of the cell of the computational grid. Thus, the size of the cell is an important adjusting parameter of the model and must be coordinated with the parameters of the dendritic structure under given growth conditions. The grain with the preferred orientation always displaces neighboring diverging grains. The converging grains are eliminated if their deviation from the vector of the temperature gradient exceeds 20°. At the smaller angles of deviation, the result of the competitive growth depends on the size of the computational cell and varies from their joint growth (at the cell size of 5 μm) to the displacement of grains with the preferred orientation (at the cell size of 20 μm). However, all of the results of the simulation agree with the experimental data available in the literature. For the efficient selection of grains with the preferred orientation, regimes with a low temperature gradient and high growth rate are favorable.
2011
Computer modelling of casting processes for heavy steel ingots
Author: Broytman O.A., Saraev D.Yu, Monastyrsky A.V., Ivanov I.A.
Source: METEC InSteelCon. Section 5: Ingot casting. – Düsseldorf, 2011.
Abstract: Heavy steel ingots are used as raw-parts for manufacturing of turbine rotors for fossil
power and nuclear power plants, mill rolls, etc. These parts have to be uniformly structured and
perfectly balanced, and therefore – defect-free. The casting technology for such large-scale steel
ingots has to be optimized in order to save resources, increase yield, and improve quality of
ingots. Computer analysis is a good way to optimize the casting technology virtually, shorten the
trial casting stage and minimize the lead time. This research work is devoted to the deep
computer analysis of traditional technologies for casting of heavy forging ingots. A number of
processes is considered: hydrodynamics, solidification, heat transfer and stress effects in ingot-
tooling system, porosity formation, feeding effectiveness and macrosegregation. The modeling is
performed using commercial casting simulation software packages as well as with some original
models. This research is targeted at development of recommendations for casting technology
optimization. Modeling results are compared with experimental data for verification and
improvement of computer models.
2007
Using of the casting simulation system “PoligonSoft” for analysis of a temperature field of aluminum alloys.
Authors: J.Bast, Y.Kotova
A source: Freiberger Forschungshefte A 892, ISBN 978-3-86012-319-5 (2007), p. 107 – 113.
Annotation: Today a great number of modeling systems in mechanical engineering are being used, the gain of their using is obvious in comparison with experiments. One of these systems is a simulation system “PoligonSoft”. This system allows improving some of the most important process variables not using of real casting, but using of computer modeling.
Computer modelling of casting processes for heavy steel ingots
Author: Broytman O.A., Saraev D.Yu, Monastyrsky A.V., Ivanov I.A.
Source: METEC InSteelCon. Section 5: Ingot casting. – Düsseldorf, 2011.
Abstract: Heavy steel ingots are used as raw-parts for manufacturing of turbine rotors for fossil
power and nuclear power plants, mill rolls, etc. These parts have to be uniformly structured and
perfectly balanced, and therefore – defect-free. The casting technology for such large-scale steel
ingots has to be optimized in order to save resources, increase yield, and improve quality of
ingots. Computer analysis is a good way to optimize the casting technology virtually, shorten the
trial casting stage and minimize the lead time. This research work is devoted to the deep
computer analysis of traditional technologies for casting of heavy forging ingots. A number of
processes is considered: hydrodynamics, solidification, heat transfer and stress effects in ingot-
tooling system, porosity formation, feeding effectiveness and macrosegregation. The modeling is
performed using commercial casting simulation software packages as well as with some original
models. This research is targeted at development of recommendations for casting technology
optimization. Modeling results are compared with experimental data for verification and
improvement of computer models.