Modelling and process optimization for heavy plate rolling of structural steel

• Autorzy: Siwecki, T.

Warianty tytułu

PL

Modelowanie i optymalizacja procesu walcowania blach grubych ze stali konstrukcyjnych

• Konferencja: 14th KomPlasTech Conference, Zakopane, January 14-17, 2007
• Języki publikacji: EN

Abstrakty

EN

The aim of the paper is to present the recent developments (in Sweden) regarding microstructure and mechanical property enhancement through thermo-mechanical controlled processing (TMCP) of structural steel plate and the use of predictive models. The key to success with TMCP-processing is to define rolling schedules combining a maximum degree of microstructural refinement with acceptably low rolling loads, good shape and surface control and high productivity. In this context, the simulation of the TMCP treatment in laboratory scale as well as the computer models for calculation of microstructure development and precipitate evolution during hot rolling are invaluable for design of rolling schedules. For good control of final microstructure, it is invaluable to have a computer model for prediction of microstructure evolution during TMCP, to enable optimal design of rolling and cooling schedules. By modelling of microstructure evolution, the steel composition and the properties of the final product can be optimised without expensive testing, so reducing the production cost of high strength steels and making them competitive in more applications. It is intended that the developed models will give steel producers essential advantages in thermo-mechanical processing, applicable to structural/microalloyed steels, so achieving optimisation of process parameters and steel chemistry. Several models based on empirical and/or semi-empirical equations describing recrystallization and recovery and have been developed around the world and applied successfully to specific steels. However, such models have limited improvement potential and typically suffer from difficulties in applicability to different steels even when these are quite similar in chemical composition. In order to gain flexibility, the models should be based on a physical description of microstructure evolution, including deformation, recovery, recrystallization, precipitation and phase transformation. Such so-called physical models should be intrinsically capable of handling multi-component systems. A brief survey is made of the models developed at the Corrosion & Metals Research Institute and used by the Swedish Steel Industry. The models can be used for predictions of recrystallization and grain growth of austenite after deformation, precipitation or dissolution of microalloying carbo-nitrides in austenite and phase transformation behaviour during accelerated cooling. The effect of TMCP- parameters, low reheating and high finish rolling temperature, as well as rolling schedules, cooling / quenching rate will be discussed with regard to the transformation characteristics as well as the strength, hardness and microstructure of structure steels.

PL

Celem artykułu jest przedstawienie ostatnich osiągnięć (w Szwecji) w zakresie poprawy mikrostruktury i własności stali poprzez termomechaniczne walcowanie (TMCP thermo-mechanical controlled processing). Przedstawienie zastosowań komputerowego modelowania w tym zakresie jest drugim celem artykułu. Symulacja TMCP w skali laboratoryjnej oraz komputerowe modelowanie w celu przewidywania rozwoju mikrostruktury i procesów wydzieleniowych podczas walcowania na gorąco są ważnym wspomaganiem projektowania technologii walcowania. W pracy przedstawiono krótki przegląd modeli opracowanych w Corrosion & Metals Research Institute i sto­sowanych przez przemysł metalurgiczny w Szwecji. Modele są stosowane do przewidywania rekrystalizacji i rozrostu ziarna austenitu po odkształceniu, procesów wydzieleniowych i rozpuszczalności węgliko-azotków w austenicie oraz przemian fazowych podczas przyspieszonego chłodzenia. Otrzymane parametry TMCP - niższe temperatury wygrzewania i wysokie temperatury końca walcowania, plany przepustów, i prędkości chłodzenia są omówione w artykule ze względu na ich wpływ na charakter przemiany fazowej oraz na mikrostrukturę i wytrzymałość wyrobów ze stali konstrukcyjnych.

Słowa kluczowe

EN

HSLA steel; modelling; microstructure; grain size; recrystallization; transformation; precipitation; microalloying; mechanical properties; hot rolling; accelerated cooling

• Czasopismo: Computer Methods in Materials Science
• Rocznik: 2007
• Tom: Vol. 7, No. 1
• Strony: 29-35
• Opis fizyczny: Bibliogr. 8 poz., rys.

Twórcy

autor

Siwecki, T.

• Corrosion & Metal Research Institute, KIMAB Drottning Kristinas vag 48, 114 28 Stockholm, Sweden

Bibliografia

• Sellars, C.M., Whiteman, J.A., 1979, Recrystallisation and Grain Growth in Hot Rolling, Met. Sci., 13, 187-194.
• Siwecki, T., 1992, Modelling of Microstructure Evolution during Recrystallization Controlled Rolling", ISIJ Int., 32, 368-376.
• Siwecki, T., Engberg, G., 1997, Recrystallization Controlled Rolling of Steel, in Thermo-Mechanical Processing -in Theory, Modelling & Practice, eds, Hutchinson, B., Andersson M., Engberg G., Karlsson B., Siwecki T., Stockholm, 1996, ASM Intern., 121-144.
• Siwecki, T., Pettersson, S., Engberg, G., 2000, Models for Prediction of HSLA Steel Behaviour During Thermal and Thermo-Mechanical Processing, in THERMEC 2000 and in Swedish Institute for Metals Research, Report IM-2000-729.
• Howe, A.A. Parker, S.V., Whittaker, N.A., Di Nunzio, P.E., Lopez, B., et al. 2002, Improved microstructural modelling of phase transformations in medium and high carbon steels, ECSC Contract 7210-PR/034 (D3.02/97), Final Report EUR 20216 EN.
• Siwecki, T., Wang, O., 2003, Microstructure evolution during energy saving heavy plate RCR rolling of Ti-V microalloyed steel, Swedish Inst. Metals Research, Report 1M-2003-565.
• Wang, X., Siwecki, T., Engberg, G., 2003, Physical Model for Prediction of Microstructure Evolution during Thermo Mechanical Processing, THERMEC 2003, ed. T. Chandra, Trans. Tech. Publications, Switzerland, Materials Science Forum, 426-432, 3801-3806.
• Sellars, C.M., Palmiere, E.J., 2005, Modelling strain induced precipitation of Nb carbonitride during multipass deformation of austenite, Materials Science Forum, 500-501, 3-14.