The influence of kinetics of phase transformations during tempering on high-speed steels mechanical properties

• Autorzy: Bała P. , Pacyna J.
• Języki publikacji: EN

Abstrakty

EN

Purpose: The main purpose of the presented paper was the determination of the influence of the phase transformation kinetics, at tempering, on the properties of high-speed steels. In order to achieve this aim investigations of the influence of continuous heating and isothermal tempering from the as-quenched state on the investigated steels hardness were performed. The advancement degree change obtained by changing the heating rate and by pre-tempering was applied in strength properties studies. Design/methodology/approach: Due to a high brittleness of tested steels it was decided to test their strength by means of the static bend test. The tests were carried out on 5 samples using the INSTRON testing machine. The microstructure of investigated steels in the as-quenched state was examined by the light microscope Axiovert 200 MAT and the scanning electron microscope Hitachi 3500 N. The measurements of hardness were performed with the Vickers HPO250 apparatus. Findings: Changing heating rates for tempering one can influence steel properties. Better results are achieved when steels are heated up to the tempering temperature with the higher rate. The heating rate increased from 15°C/min to 300°C/min improved the investigated steels bending strength by 8%. Research limitations/implications: Phase transformations at tempering, being diffusive transformations, are characterised by the determined kinetics depending on a temperature and time of heating. Complexity of processes occurring at tempering, as well as the diversity of influencing factors creates the possibility of searching for prolonging the life-span of tools made of high-speed steels. Regardless that only two, well known high-speed steels HS18-0-1 and HS6-5-2 were tested, the obtained results can be referred to the whole group of high-speed steels. Practical implications: On the basis of the obtained results it is possible to select the tempering parameters in such a way as to achieve the optimal combination of strength and plastic properties needed for the anticipated application of the given high-speed steel. Originality/value: This results should be of interest to engineers concerned with designing the new technologies of high-speed steels tempering.

Słowa kluczowe

EN

tool material; tempering; high-speed steel; mechanical properties

PL

materiał narzędziowy; odpuszczanie; stal szybkotnąca; właściwości mechaniczne

• Wydawca: International OCSCO World Press
• Czasopismo: Journal of Achievements in Materials and Manufacturing Engineering
• Rocznik: 2010
• Tom: Vol. 43, nr 1
• Strony: 64--71
• Opis fizyczny: Bibliogr. 17 poz., rys., tabl.

Twórcy

autor

Bała P.

autor

Pacyna J.

• Faculty of Metals Engineering and Industrial Computer Science, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Krakow, Poland,

Bibliografia

• [1] R.W.K. Honeycombe, H.K.D.H. Bhadeshia, Steels. Microstructure and properties, 2nd ed. London, Edward Arnold, 1995.
• [2] A.K. Sinha, Physical metallurgy handbook, The McGraw-Hill Companies, Inc., 2003.
• [3] L.A. Dobrzański, W. Kasprzak, J. Mazurkiewicz, The structure and properties W-Mo-V-Co high-speed steel of the type 11-2-2-5 after heat treatment, Proceedings of the 4th International Scientific Conference „Achievements in Mechanical and Materials Engineering” AMME’95, Gliwice- Wisła, 1995, 83-86 (in Polish).
• [4] M. Blicharski, Steels, WNT, Warsaw, 2004 (in Polish).
• [5] D.E. Kaputkin, Reversible martensitic transformation, ageing and low-temperature tempering of iron-carbon martensite, Materials Science and Engineering A 438-440 (2006) 207-211
• [6] R. Padmanabhan, W.E. Wood, Precipitation of carbide in martensite, Materials Science and Engineering 65 (1984) 289-297.
• [7] K.A. Taylor, G.B. Olson, M. Cohen, J.B. Vander Sande, Carbide precipitation during stage I tempering of Fe-Ni- Cmartensites, Metallurgical Transactions A 20A/12 (1989) 2749-2766.
• [8] S. Murphy, J.A. Whiteman, The precipitation of epsilon-carbide in twinned martensite, Metallurgical Transactions 1 (1970) 843-848.
• [9] R.C. Thomson, M.K. Miller, Carbide precipitation in martensite during the early stages of tempering Cr- and Mo-containing low alloy steels, Acta Metallurgica 46/6 (1998) 2203-2213.
• [10] A.D.B. Gingell, H.K.D.H. Bhadeshia, D.G. Jones, K.J.A. Mawella, Carbide precipitation in some secondary hardened steels, Journal of Materials Science 32 (1997) 4815-4820.
• [11] L.A. Dobrzański, M. Ligraski, Role of Ti in the W-Mo-V high-speed steels, Proceedings of the 4th International Scientific Conference „Achievements in Mechanical and Materials Engineering” AMME’95, Gliwice-Wisla, 1995, 87-90.
• [12] P. Bała, J. Pacyna, J. Krawczyk, The kinetics of phase transformations during the tempering of HS18-0-1 high-speed steel, Journal of Achievements in Materials and Manufacturing Engineering 19/1 (2006) 19-25.
• [13] P. Bała, J. Pacyna, J. Krawczyk, The kinetics of phase transformations during the tempering of HS6-5-2 high-speed steel, Journal of Achievements in Materials and Manufacturing Engineering 18 (2006) 47-50.
• [14] P. Bała, The kinetics of phase transformations during tempering and its influence on the mechanical properties, PhD thesis, AGH University of Science and Technology, Thesis Supervisor J. Pacyna, Cracow, 2007 (in Polish).
• [15] L.A. Dobrzański, M. Adamiak, W. Kasprzak, Structure and properties of the heat-treated and PVD coated W-Mo-V-Co high-speed steel of the 9-2-2-5 type, Proceedings of the 7th International Scientific Conference „Achievements in Mechanical and Materials Engineering” AMME’98, Gliwice-Zakopane, 1998, 107-10.
• [16] P. Bała and J. Pacyna, The kinetics of phase transformations during tempering in high-speed steels, ournal of Achievements in Materials and Manufacturing Engineering 3 (2007) 15-8.
• [17] P. Bała, J. Pacyna, The influence of kinetics phase transformation during tempering on the mechanical properties of HS6-5-2 steel, Journal of Achievements in Materials and Manufacturing Engineering 28 (2008) 123-130.