Numerical analysis of thermo-mechanical phenomena of hardening process of elements made of carbon steel C80U

• Autorzy: Bokota A. , Domański T.

Warianty tytułu

PL

Analiza numeryczna zjawisk termomechanicznych procesu hartowania elementów wykonywanych z węglowej stali C80U

• Konferencja: Scientific Seminar Integrated Study on the Foundations of Plastic Deformation of Metals PLASTMET'06 (5; 28.11-01.12.2006; Łańcut, Poland)
• Języki publikacji: EN

Abstrakty

EN

The work concerns numerical analysis of thermal phenomena, phase transformations and mechanical phenomena associated with hardening of carbon steel C80U. The following transformations were assumed: initial structure – austenite, austenite – perlite, bainite and austenite – martensite. Numerical algorithms for evaluation of fractions of phases and their kinetics based on continuous heating and cooling diagrams (CCT) were worked out. In the algorithm of thermal phenomena relation of thermophysical values to temperature and source of phase transformations were taken into account. The dilatometric tests on the simulator of thermal cycles were performed, during which the hardening of the elements made of carbon steel C80U was simulated. The results of dilatometric tests were compared with the results of the test numerical simulations. In this way the derived models for evaluating phase content and kinetics of transformations in heating and cooling processes were verified. The stresses generated during hardening were assumed to result from thermal load, structural plastic deformations and transformation plasticity. The hardened material was assumed to be elastic-plastic, and in order to mark plastic strains the non-isothermal plastic law of flow with the isotropic strengthening and condition plasticity of Huber-Misses were used. Thermophysical properties present in the model of mechanical phenomena were made dependant on both the phase composition and on temperatures. The results of numerical simulations confirm correctness of the algorithms that were worked out.

PL

Praca dotyczy analizy numerycznej zjawisk cieplnych, przemian fazowych i zjawisk mechanicznych towarzyszących hartowaniu węglowej stali C80U. Założono istnienie przemian: struktura wyjściowa – austenit, austenit – perlit, bainit oraz austenit – martenzyt. Opracowano algorytmy numeryczne szacowania ułamków faz oraz ich kinetyki oparte na wykresach ciągłego nagrzewania oraz ciągłego chłodzenia (CTPc). W algorytmie zjawisk cieplnych uwzględniono zalezność wielkości termofizycznych od temperatury oraz źródła przemian fazowych. W celu zweryfikowania modelu szacowania udziałów fazowych i kinetyki przemian w procesach nagrzewania i chłodzenia wykonano badania dylatometryczne na symulatorze cykli cieplnych, podczas których symulowano hartowanie elementów wykonanych ze stali C80U. Wyniki badań dylatometrycznych porównano z wynikami symulacji numerycznej. Przyjęto, że naprężenia generujące się podczas hartowania są wynikiem obciążenia termicznego, odkształceń strukturalnych, plastycznych i odkształceń transformacyjnych. Założono, że hartowany materiał jest sprężysto-plastyczny, a do wyznaczania odkształceń plastycznych zastosowano prawo nieizotermicznego plastycznego płynięcia ze wzmocnieniem izotropowym i warunkiem plastyczności Hubera-Misesa. Wielkości termofizyczne występujące w modelu zjawisk mechanicznych uzależniono zarówno od składu fazowego jak i od temperatury. Wyniki symulacji numerycznych potwierdzają poprawność opracowanych algorytmów.

Słowa kluczowe

EN

carbon steel; hardening process of steel; thermomechanica

PL

stal węglowa; hartowanie stali; termomechanika

• Wydawca: Institute of Metallurgy and Materials Science of Polish Academy of Sciences ; Committee of Materials Engineering and Metallurgy of Polish Academy of Sciences
• Czasopismo: Archives of Metallurgy and Materials
• Rocznik: 2007
• Tom: Vol. 52, iss. 2
• Strony: 277--288
• Opis fizyczny: Bibliogr. 27 poz., rys.

Twórcy

autor

Bokota A.

autor

Domański T.

• Institute of Mechanics and Machine Design, Częstochowa University of Technology, 42-200 Częstochowa, 73 St. Dąbrowskiego Str.

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