Effects of Nb, Ti and V on recrystallization kinetics of austenite in microalloyed steels

• Autorzy: Opiela M. , Ozgowicz W.
• Języki publikacji: EN

Abstrakty

EN

Purpose: The work presents research results of impact of Nb, Ti and V microadditions on flow stress, recrystallization kinetics and microstructure of newly elaborated steels assigned for production of forged machine parts, using the method of thermo-mechanical treatment. Design/methodology/approach: The study was performed with the use of Gleeble 3800 simulator. Stress-strain curves were determined during continuous compression test in a temperature range from 900 to 1100°C and at a strain rate of 1, 10 and 50 s^-1. In order to determine recrystallization kinetics of plastically deformed austenite, discontinuous compression tests of specimens were done with a given strain at the rate of 10 s^-1., in a temperature range from 900 to 1100°C, with isothermal holding of samples between successive stages of deformation for 2 to 100 s. Recrystallization kinetics of plastically deformed austenite was described using the Johnson-Mehl-Avrami equation. The observations of microstructures of thin foils were done using JEOL JEM 3010 transmission electron microscope. Findings: Basing on the analysis of the form and the course of curves obtained in the compression test, it was found that in the studied range of parameters of hot plastic deformation, the decrease of strain hardening of studied steels is caused by the process of continuous dynamic recrystallization. This is also confirmed by calculation results of activation energy of plastic deformation process. Performed two-stages compression tests revealed that microadditions introduced into steel considerably influence the kinetics of static recrystallization. Research limitations/implications: It was found that the time necessary for a total course of recrystallization of austenite is too long to be accepted in the production process of forgings. Practical implications: Executed hot compression tests will contribute to establishing conditions of forging with the method of thermo-mechanical treatment. Originality/value: Strain-stress curves and recrystallization kinetics curves of newly elaborated microalloyed steels have been determined.

Słowa kluczowe

EN

microalloyed steel; thermomechanical treatment; dynamic recrystallization; static recrystallization; softening kinetics

• Wydawca: International OCSCO World Press
• Czasopismo: Journal of Achievements in Materials and Manufacturing Engineering
• Rocznik: 2012
• Tom: Vol. 55, nr 2
• Strony: 759--771
• Opis fizyczny: Bibliogr. 16 poz., rys., tab.

Twórcy

autor

Opiela M.

• Division of Constructional and Special Materials, Institute of Engineering Materials and Biomaterials, Silesian University of Technology, ul. Konarskiego 18a, 44-100 Gliwice, Poland

autor

Ozgowicz W.

• Division of Constructional and Special Materials, Institute of Engineering Materials and Biomaterials, Silesian University of Technology, ul. Konarskiego 18a, 44-100 Gliwice, Poland

Bibliografia

• [1] A. Ghosh, S. Das, S. Chatterjee, B. Mishra, P. Ramachandra, Influence of thermo-mechanical processing and different post-cooling techniques on structure and properties of an ultra low carbon Cu bearing HSLA forging, Materials Science and Engineering A348 (2003) 299-308.
• [2] D.K. Matlock, G. Krauss, J.G. Speer, Microstructures and properties of direct-cooled microalloy forging steels, Journal of Materials Processing and Technology 117 (2001) 324-328.
• [3] P. Skubisz, H. Adrian, J. Sińczak, Controlled cooling of drop forged microalloyed-steel automotive crankshaft, Archives of Metallurgy and Materials 56/1 (2011) 93-107.
• [4] D. Jandowá, R. Divišová, L. Skálová, J. Drnek, Refinement of steel microstructure by free-forging, Journal of Achievements in Materials and Manufacturing Engineering 16/1-2 (2006) 17-24.
• [5] J. Adamczyk, M. Opiela, Engineering of forged products of microalloyed constructional steels, Journal of Achievements in Materials and Manufacturing Engineering 15/1-2 (2009) 159-165.
• [6] J. Sińczak, J. Majta, M. Głowacki, M. Pietrzyk, Prediction of mechanical properties of heavy forgings, Journal of Materials Processing and Technology 80-81 (1998) 166-173.
• [7] A. Grajcar, R. Kuziak, Softening kinetics in Nb-microalloyed TRIP steels with increased Mn content, Advanced Materials Research 314-316 (2011) 119-122.
• [8] W. Ozgowicz, M. Opiela, A. Grajcar, E. Kalinowska-Ozgowicz, W. Krukiewicz, Metallurgical products of microalloy constructional steels, Journal of Achievements in Materials and Manufacturing Engineering 44/1 (2011) 7-34.
• [9] T. Gladman, The Physical Metallurgy of Microalloyed Steels, The Institute of Materials, London, 1997.
• [10] J. Adamczyk, Development of the microalloyed constructional steels, Journal of Achievements in Materials and Manufacturing Engineering 14/1-2 (2006) 9-20.
• [11] H.L. Andrade, M.G. Akben, J.J. Jonas, Effect of molybdenium, niobium, and vanadium on static recovery and recrystallization and on solute strengthening in microalloyed steels, Metallurgical Transactions 14A (1983) 1967-1977.
• [12] J. Adamczyk, Engineering of Metallic Materials, Silesian University of Technology Publishers, Gliwice, 2004 (in Polish).
• [13] S.F. Medina, M. Gomez, P.P. Gomez, Effect of V and Nb on static recrystallization of austenite and precipitate size in microalloyed steels, Journal of Materials Science and Technology 45 (2010) 5553-5557.
• [14] A. Grajcar, Structural and mechanical behavior of TRIP-type microalloyed steel in hot-working conditions, Journal of Achievements in Materials and Manufacturing Engineering 30/1 (2008) 27-34.
• [15] C.M. Sellars, Proceedings of the International Conference “HSLA Steels’85”, Chinese Society of Metals, Beijing, 1985, 12-22.
• [16] M. Opiela, Analysis of the kinetics of precipitation of MX-type interstitial phases in microalloyed steels, Journal of Achievements in Materials and Manufacturing Engineering 47/1 (2011) 7-18.