Mathematical modeling of structure and mechanical properties of steel tubes production

• Autorzy: Kvačkaj T. , Zemko M.

Warianty tytułu

PL

Model matematyczny struktury i własności mechanicznych rur bez szwu walcowanych na gorąco

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

Abstrakty

EN

Mathematical modeling of structure and mechanical properties of steel tubes production Kvačkaj T.1); Zemko M.1) 1) Department of Metal Forming, Faculty of Metallurgy, TU of Košice, Slovakia The article deals with FEM analysis, with mathematical modeling of structure evolution and with prediction of mechanical properties during hot rolling of seamless steel tubes. There is a brief description of stretch-reducing mill in the introduction. It is a forming unit that reduces diameter of the tube semi-finished product and at the same time changes the thickness of the wall without inner tool. In this unit there are achieving the final dimensions and after cooling process also the final mechanical properties of hot rolled tubes. Mathematical model of stretch-reducing mill of Železiarne Podbrezová, Inc., was created in Deform 3D software. Calibration sequence for rolling tube semi finished product diameter 144 mm and wall thickness 4,7 mm to diameter 88,9 mm and wall thickness 5 mm was chosen for creation of mathematical model of stretch-reducing mill. This calibration sequence consists of eleven rolling stands. Numerical simulation was created on mathematical model. By using the numerical simulation the values of thermo-mechanical parameters for each stand were gained. Time dependencies of strain, strain rate and rolling force were made from the obtained values. The next part presents mathematical model describing the tube production for low carbon steels grade St52 on analyzed calibration sequence. Model is valid for range of rolling start temperatures 870 – 960 °C and start rolling velocity 1,23 m.s-1. Model includes: - calculation of deformation temperature on each rolling stand in dependency on heating temperature, - calculation of kinetics of static recrystallization in conditions of continual cooling, - calculation of diameter of austenite grain after each deformation, - calculation of Ar3 and Ar1 temperatures in dependency on chemical composition, austenite grain size, amount of residual deformation and cooling rate, - calculation of austenite grain size after cooling to Ar3 temperature, - calculation of ferrite grain size in dependency on chemical composition, austenite grain size, amount of residual deformation and cooling rate, - calculation of structural fractions (ferrite, pearlite, bainite) in dependency on chemical composition, austenite grain size and cooling rate, - calculation of yield and tensile strength in dependency of structural fractions and ferrite grain size, - estimation of ductility for normalization conditions in dependency on chemical composition. Numerical simulation and process condition statistic data were used for calculation of material temperature both during tube pass through stretch-reducing mill and during cooling. Values of strain and strain rate from numerical simulation were substituted into the mathematical models. The calculated values were compared with experimental ones resulting from mechanical tests of industry rolled tubes of various chemical compositions. Good agreement of structural and mechanical properties was achieved for all chemical compositions and treatment conditions. The conclusion deals with the possibilities of increasing the accuracy of presented mathematical model as well as the possibilities of extension dimension assortment and areas of applications of mathematical modeling of seamless steel tubes production.

PL

Symulacje numeryczne z wykorzystaniem MES w połączeniu z modelowaniem matematycznym rozwoju struktury oraz opisem własności mechanicznych podczas walcowania na gorąco rur bez szwu jest tematem niniejszej pracy. Model matematyczny reduktora pracującego z naciągiem w Żeleziarne Podbrezova, Inc. został stworzony w programie Deform 3D. Do obliczeń pola temperatur podczas przejścia rury przez reduktor oraz późniejszego chłodzenia wykorzystano modelowanie nume­ryczne i dane statystyczne z rzeczywistego procesu. Uzyskane z symulacji wartości odkształceń i prędkości odkształcenia przeniesiono do modelu matematycznego. W pracy porównano wyniki symulacji z wynikami doświadczalnymi otrzymanymi dla różnych składów chemicznych materiału. Porównanie to wykazało dobrą zgodności struktury oraz własności mechanicznych dla wszystkich badanych składów chemicznych i warunków procesu.

Słowa kluczowe

EN

stretch-reducing mili; tube; controlled forming; numerical simulation; static recrystallization; prediction of structure; prediction of mechanical properties

• Wydawca: Wydawnictwa AGH
• Czasopismo: Computer Methods in Materials Science
• Rocznik: 2007
• Tom: Vol. 7, No. 1
• Strony: 17--23
• Opis fizyczny: Bibliogr. 13 poz., rys.

Twórcy

autor

Kvačkaj T.

autor

Zemko M.

• Department of Metal Forming, Faculty of Metallurgy, TU of Kośice, Slovakia

Bibliografia

• Železiarne Podbrezova, a.s., 2001, racovnobezpečnostny   a vyrobu lup, (in Slovak).
• Kvačkaj, T., 1992,Smery riešenia predosiahnutie požadovanych strukturalnych a mechanickych vlastnosti plochych  vyvalkov. in:  Medzinarodna vedecka konferencia, Kosice, 184-190, (in Slovak).
• Anan, G., Nakajima, S., Miyhara, M., Nanba, S., Umemoto, M., Hiramatsu, A., Moriya, A., Watanabe T., 1992, A Model for Recovery and Recrystallization of Hot Deformed Austenite Considering Structural Heterogeneity, ISIJ Int., 32, 261-266.
• Zemko, M., Model for Recovery and Recrystallization of Hot Deformed Austenite Considering Structural Heterogeneity, ISU Int., 32, 261-266.
• Nanba, S., Kitamura, M., Shimada, M., Katsumata, M., Inoue, T., Imamura, H., Maeda, Y., Hattori, S., 1992, Prediction of Microstructure Distribution in the Through-Thickness Direction  During  and After Hot Rolling  in  Carbon Steels, ISIJ Int., 32, 377-386.
• Maccagno, T.M., Jonas, J.J., Hodgson, P.D., 1996, Spreadsheet modelling of grain size evolution during rod rolling, ISIJ Int., 36, 720-728.
• Kvačkaj, T., 2004,    Modelovanie   plastickych   deformacii,prednašky, rukopis, Košice, (in Slovak).
• Zemko, M.,  2006, Vyskum plastickych  deformacii pomocou MKP, Dizertačna praca. Košice, (in Slovak).
• Zhang, Y.T., Li, D.Z., Li, Y.Y., 2002, Modeling of ferrite grain growth of low carbon steels during hot rolling, Acta Metallurgica Sinica (English Letters), 15, 267-271.
• Sellars, C.M., Beynon, J.H., 1985, Proc. Conf. HSLA Steels, eds., Dunne, D.P., Chandra, T., 142-150.
• Saito, Y., Saeki, M., Nishida, M., 1980, Optimum Designing of Mechanical Properties of Hot-Rolled Steel Coils by Controlled Rolling and Cooling, ISIJ Int., 28, 1309-1320.
• Sellars,  C.M.,  Whiteman,  J.A.,   1979,  Recrystallization  and Grain Growth in Hot Rolling, Metal Science, 13, 187-194.
• Deform-3D Version 5.03 User Manual, 2004, Scientific Forming Technologies Corporation.