The studies of nodular graphite cast iron early stages austempering

• Autorzy: Krzyńska A. , Kaczorowski M.
• Języki publikacji: EN

Abstrakty

EN

The results of early stage of ductile cast iron austempering are presented. The aim of the investigations was to look closer into the structure - mechanical properties relationships of this very attractive cast material. The experiment was carried out with enriched with Cu EN-GJS-500-7 grade ductile iron. The specimens were first solution heat treated 1 hour in 910oC and then isothermally quenched for different time in molten tin at the temperature 275°C. The mechanical properties of as cast and heat treated specimens were tested to evaluate tensile Rm and yield strength R p, 0.2 and elongation A5. Additionally hardness measurements were carried out using Brinell-Rockwell method. Structure of the specimens both as cast and after austempering was studied using conventional light microscopy. Moreover, scanning electron microscopy (SEM) was applied for fracture surface observations. It was concluded that short time low temperature austempering lead to formation martensitic microstructure characterized by very high hardness with almost zero ductility. The lack of ductility make the material very sensitive to any structure defects which work as a stress concentrators which strongly influence the strength of heat treated ductile iron specimens.

Słowa kluczowe

EN

ADI; heat treatment; structure; properties

PL

żeliwo ADI; żeliwo sferoidalne; obróbka cieplna; struktura; właściwości

• Wydawca: Komisja Odlewnictwa Polskiej Akademii Nauk Oddział w Katowicach
• Czasopismo: Archives of Foundry Engineering
• Rocznik: 2008
• Tom: Vol. 8, iss. 4
• Strony: 87--92
• Opis fizyczny: Bibliogr. 9 poz., rys., tab.

Twórcy

autor

Krzyńska A.

autor

Kaczorowski M.

• Warsaw University of Technology, Faculty of Production Engineering, Institute of Materials Processing, ul. Narbutta 85, 02-524 Warszawa,

Bibliografia

• [1] J.F. Janowiak, R.B. Gundlach, Development of Ductile Iron for Commercial Austempering, AFS Trans., 86 (1983) 377.
• [2] The Solrelmetal Book of Ductile Iron, RIO TINTO&Titanium INC., Montreal (Quebec) Canada, 2004.
• [3] http://indigo4.gr.rwth-aachen.de/tlyer/squeeze/pic3.html.
• [4] B.V. Kovacs: Heat Treating of Austempered Ductile Iron, AFS Transactions, 99 (1991) 281 - 290.
• [5] M. Kaczorowski, A. Krzyńska, The mystery of ADI, Archives of Foundry Technology, vol. 7 (2007) 111-116.
• [6] M. Kaczorowski, A. Krzyńska, The study of mechanical properties of structure of austempered ductile iron (ADI), Proc. 4-th Int. Conf. on Advances in Production Engineering, APE'07, Warsaw, June 2007, 171-180.
• [7] Metals Handbook, Ninth Edition, vol. 12 Fractography, ASM International Metals Park, Ohio, USA, 1987.
• [8] Ju.N. Taran, K.I. Uzlow, A.I. Kucow, Theoretical and practical aspects of ductile iron austempering, Proc. Int. Conference Ductile Iron the Chance of Polish Foundries Development, Kraków, June (1996), chapt.6, pp. 1-23 (in Polish).
• [9] M. Kaczorowski, D. Myszka, On the differences between mechanical properties and structure of ductile iron castings Austempered using conventional and direct method, Int. Journal for Manufacturing Science & Technology, vol. 7 No. 1 (2005) 33-39.