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Petros C Mavroidis - One of the best experts on this subject based on the ideXlab platform.

Henrik Horn - One of the best experts on this subject based on the ideXlab platform.

S. F. Lukashevich - One of the best experts on this subject based on the ideXlab platform.

Miran Pirnat - One of the best experts on this subject based on the ideXlab platform.

  • A THERMODYNAMIC AND KINETIC STUDY OF THE SOLIDIFICATION AND DECARBURIZATION OF Malleable Cast Iron TERMODINAMI^NA IN KINETI^NA ANALIZA STRJEVANJA IN RAZOGLJI^ENJA BELEGA LITEGA @ELEZA
    2020
    Co-Authors: Miran Pirnat
    Abstract:

    An analysis of the solidification and decarburization of white-heart Malleable Cast Iron (MCI) is presented. The solidification and decarburization courses were examined with simple and differential scanning calorimetry. The microstructure characteristics and the physical properties of the white-heart Malleable Cast Iron changed during the decarburization process. Also, the electrical resistivity changed with the change of carbon contents and the macro-and microstructures. Based on this hypothesis, a measuring method for simultaneous measurements of the electrical resistivity and dimensional variations during the decarburization process of white-heart Malleable Cast Iron was developed. In addition, a physico-mathematical model was developed to follow the carbon concentration and to determine the depths of the decarburization zone during the decarburization process. The decarburization process was presented as a function of the specific electrical conductivity, the carbon concentration and the decarburization time. ^lanek opisuje spremljanje strjevanja in razoglji~enja belega litegaeleza. Potek strjevanja in razoglji~enja sta bila preiskana z enostavno in diferen~no vrsti~no kalorimetrijo. Med procesom razoglji~enja belega litegaeleza se spreminjajo zna~ilnosti zgradbe in fizikalne lastnosti. Prav tako se zaradi spremembe koncentracije ogljika ter makro- in mikrostrukture spreminja tudi elektri~na upornost. Na tej hipotezi je bila razvita merilna metoda isto~asnega merjenja elektri~ne upornosti in dimenzijskih sprememb med procesom razoglji~enja belega litegaeleza. Razvit je fizikalno-matemati~ni model, s katerim je mono med procesom razoglji~enja spremljati koncentracijo ogljika in dolo~iti globino razoglji~enja. Potek procesa razoglji~enja je prikazan kot funkcija specifi~ne elektri~ne upornosti, koncentracije ogljika in ~asa razoglji~enja. White-heart Malleable Cast Iron (MCI) was prepared from a chilled hypoeutectic Iron alloy. Afterwards, it was decarburized to achieve adequate mechanical properties. The morphology of the solidified phases, the temperature regions of the corresponding reactions and the formed phases were determined with a thermodynamic analysis of the MCI solidification and decarburization process. The fraction of pearlite and the heat treatment 1 are essen- tial to obtain the desired properties of the MCI. The fol- lowing methods were used to examine the solidification process and solid-state transformations: simple thermal analyses (TA), dilatometric analyses, and simultaneous thermal analyses (DSC). An "in situ" measuring appara- tus, as a part of the laboratory equipment, was also de- veloped to follow the electrical resistivity during the decarburization process. The goal of the examination was to design a model for the "in situ" monitoring of the decarburization process by determining the carbon con- centrations and the depths of decarburization zone. The thermal analyses could be used for the quality control of the MCI, since it made it possible to determine the met- allurgical quality of the Cast Iron in the shortest possible time. The chemical composition and the nucleation con-

  • a thermodynamic and kinetic study of the solidification and decarburization of Malleable Cast Iron termodinami na in kineti na analiza strjevanja in razoglji enja belega litega eleza
    2011
    Co-Authors: Miran Pirnat
    Abstract:

    An analysis of the solidification and decarburization of white-heart Malleable Cast Iron (MCI) is presented. The solidification and decarburization courses were examined with simple and differential scanning calorimetry. The microstructure characteristics and the physical properties of the white-heart Malleable Cast Iron changed during the decarburization process. Also, the electrical resistivity changed with the change of carbon contents and the macro-and microstructures. Based on this hypothesis, a measuring method for simultaneous measurements of the electrical resistivity and dimensional variations during the decarburization process of white-heart Malleable Cast Iron was developed. In addition, a physico-mathematical model was developed to follow the carbon concentration and to determine the depths of the decarburization zone during the decarburization process. The decarburization process was presented as a function of the specific electrical conductivity, the carbon concentration and the decarburization time. ^lanek opisuje spremljanje strjevanja in razoglji~enja belega litegaeleza. Potek strjevanja in razoglji~enja sta bila preiskana z enostavno in diferen~no vrsti~no kalorimetrijo. Med procesom razoglji~enja belega litegaeleza se spreminjajo zna~ilnosti zgradbe in fizikalne lastnosti. Prav tako se zaradi spremembe koncentracije ogljika ter makro- in mikrostrukture spreminja tudi elektri~na upornost. Na tej hipotezi je bila razvita merilna metoda isto~asnega merjenja elektri~ne upornosti in dimenzijskih sprememb med procesom razoglji~enja belega litegaeleza. Razvit je fizikalno-matemati~ni model, s katerim je mono med procesom razoglji~enja spremljati koncentracijo ogljika in dolo~iti globino razoglji~enja. Potek procesa razoglji~enja je prikazan kot funkcija specifi~ne elektri~ne upornosti, koncentracije ogljika in ~asa razoglji~enja. White-heart Malleable Cast Iron (MCI) was prepared from a chilled hypoeutectic Iron alloy. Afterwards, it was decarburized to achieve adequate mechanical properties. The morphology of the solidified phases, the temperature regions of the corresponding reactions and the formed phases were determined with a thermodynamic analysis of the MCI solidification and decarburization process. The fraction of pearlite and the heat treatment 1 are essen- tial to obtain the desired properties of the MCI. The fol- lowing methods were used to examine the solidification process and solid-state transformations: simple thermal analyses (TA), dilatometric analyses, and simultaneous thermal analyses (DSC). An "in situ" measuring appara- tus, as a part of the laboratory equipment, was also de- veloped to follow the electrical resistivity during the decarburization process. The goal of the examination was to design a model for the "in situ" monitoring of the decarburization process by determining the carbon con- centrations and the depths of decarburization zone. The thermal analyses could be used for the quality control of the MCI, since it made it possible to determine the met- allurgical quality of the Cast Iron in the shortest possible time. The chemical composition and the nucleation con-

Itzhak Green - One of the best experts on this subject based on the ideXlab platform.

  • Elasto-plastic hemispherical contact models for various mechanical properties
    Proceedings of the Institution of Mechanical Engineers Part J: Journal of Engineering Tribology, 2020
    Co-Authors: John J. Quicksall, Robert L. Jackson, Itzhak Green
    Abstract:

    AbstractThis work uses the finite element technique to model the elastoplastic deformation of a hemisphere contacting a rigid flat for various material properties typical of aluminium, bronze, copper, titanium and Malleable Cast Iron. Additionally, this work conducted parametric finite element method (FEM) tests on a generic material in which the elastic modulus and Poisson's ratio are varied independently while the yield strength is held constant. A larger spectrum of material properties are covered in this work than in most previous studies. The results from this work are compared with two previously formulated elastoplastic models simulating the deformation of a hemisphere in contact with a rigid flat. Both of the previously formulated models use carbon steel mechanical properties to arrive at empirical formulations implied to pertain to various materials. While both models considered several carbon steels with various yield strengths, they did not test materials with various Poisson's ratios or elasti...

  • Elasto-Plastic Hemispherical Contact Models for Various Mechanical Properties
    World Tribology Congress III Volume 1, 2005
    Co-Authors: John J. Quicksall, Robert L. Jackson, Itzhak Green
    Abstract:

    This work uses the finite element technique to model the elasto-plastic deformation of a hemisphere contacting a rigid flat for various material properties typical of aluminum, bronze, copper, titanium and Malleable Cast Iron. Additionally, this work conducted parametric FEM tests on a generic material in which the elastic modulus and Poisson’s ratio are varied independently while the yield strength is held constant. A larger spectrum of material properties are covered in this work than in most previous works. The results are compared to two previously formulated elasto-plastic models simulating the deformation of a hemisphere in contact with a rigid flat. Both of the previously formulated models use carbon steel mechanical properties to arrive at empirical formulations implied to pertain to various materials. While both models considered several carbon steels with varying yield strengths, they did not test materials with varying Poisson’s ratio or elastic modulus. The previously generated elasto-plastic models give fairly good predictions when compared to the FEM results for various material properties from the current work, except that one model produces more accurate predictions overall, especially at large deformations where other models neglect important trends due to decreases in “hardness” with increasing deformation.Copyright © 2005 by ASME