Initial Assessment of Graphite Precipitates in Vermicular Cast Iron in the As-Cast State and after Thermal Treatments

• Autorzy: Soiński M. S. , Jakubus Aneta , Borowiecki B. , Mierzwa P.

Identyfikatory

DOI

10.24425/afe.2021.139762

• Języki publikacji: EN

Abstrakty

EN

The purpose of the work was to determine the morphology of graphite that occurs in vermicular cast iron, both in the as-cast state and after heat treatment including austenitization (held at a temperature of 890°C or 960°C for 90 or 150 min) and isothermal quenching (i.e. austempering, at a temperature of 290°C or 390°C for 90 or 150 min). In this case, the aim here was to investigate whether the heat treatment performed, in addition to the undisputed influence of the cast iron matrix on the formation of austenite and ferrite, also affects the morphology of the vermicular graphite precipitates and to what extent. The investigations were carried out for the specimens cut from test coupons cast in the shape of an inverted U letter (type IIb according to the applicable standard); they were taken from the 25mm thick walls of their test parts. The morphology of graphite precipitates in cast iron was investigated using a Metaplan 2 metallographic microscope and a Quantimet 570 Color image analyzer. The shape factor F was calculated as the quotient of the area of given graphite precipitation and the square of its perimeter. The degree of vermicularization of graphite was determined as the ratio of the sum of the graphite surface and precipitates with F <0.05 to the total area occupied by all the precipitations of the graphite surface. The examinations performed revealed that all the heat-treated samples made of vermicular graphite exhibited the lower degree of vermicularization of the graphite compared to the corresponding samples in the as-cast state (the structure contains a greater fraction of the nodular or nearly nodular precipitates). Heat treatment also caused a reduction in the average size of graphite precipitates, which was about 225μm2 for the as-cast state, and dropped to approximately 170-200 μm2 after the austenitization and austempering processes.

Słowa kluczowe

EN

vermicular cast iron; graphite precipitates; thermal treatments; austempering

PL

żeliwo wermikularne; morfologia grafitu; obróbka termiczna; hartowanie

• Wydawca: Komisja Odlewnictwa Polskiej Akademii Nauk Oddział w Katowicach
• Czasopismo: Archives of Foundry Engineering
• Rocznik: 2021
• Tom: Vol. 21, iss. 4
• Strony: 131--136
• Opis fizyczny: Bibliogr. 24 poz., rys., tab., wykr.

Twórcy

autor

Soiński M. S.

• The Jacob of Paradies University in Gorzów Wielkopolski, Gorzów Wielkopolski, Poland

autor

Jakubus Aneta

• The Jacob of Paradies University in Gorzów Wielkopolski, Gorzów Wielkopolski, Poland

autor

Borowiecki B.

• The Jacob of Paradies University in Gorzów Wielkopolski, Gorzów Wielkopolski, Poland

autor

Mierzwa P.

• Czestochowa University of Technology, Poland

Bibliografia

• [1] Sorelmetal, On the nodular cast iron. (2006). Warsaw: Ed. Metals & Minerals Ltd.
• [2] Tupaj, M., Orłowicz, A. W., Mróz, M., Kupiec, B., et al. (2020). Ultrasonic Testing of Vermicular Cast Iron Microstructure. Archives of Foundry Engineering. 20(4), 36-40. DOI:10.24425/afe.2020.133345.
• [3] Guzik, E. & Kleingartner, T. (2009). A study on the structure and mechanical properties of vermicular cast iron with pearlitic-ferritic matrix. Archives of Foundry Engineering. 9(3), 55-60.
• [4] Zhang, M.X., Pang, J.C., Qiu, Y., Li, S.X., et al. (2020). Influence of microstructure on the thermo-mechanical fatigue behavior and life of vermicular graphite cast irons. Materials Science & Engineering A. 771, 138617. doi.org /10.1016/J.MSEA.2019.138617.
• [5] Zhang, Y., Guo, E., Wang, L., Zhao, S., et al. (2020). Effect of the matrix structure on vermicular graphite cast iron properties. International Journal of Materials Research. 111(5), 379-384. doi.org/10.3139/146.111891.
• [6] Qiaoqin, G., Zhong, Y., Ding, G., Dong, T. et al. (2019). Research on the oxidation mechanism of vermicular graphite cast iron. Materials. 12, 3130; DOI:10.3390/ma12193130.
• [7] Perzyk, M., Waszkiewicz, S., Kaczorowski, M., Jopkiewicz, A. (2000). Foundry. Warsaw: ED. Science and Technology.
• [8] Kosowski, A. (2008). Foundations of foundry. Krakow: Ed. Scientific Akapit.
• [9] Soiński, M.S. & Warchala, T. (2006). Cast iron moulds for glassmaking industry. Archives of Foundry. 6(19), 289-294.
• [10] Warchala, T. (1988). Metallurgy and iron founding. Part 1 The structure and properties of cast iron. Ed. Częstochowa University of Technology.
• [11] Andrsova, Z., Volesky, L. (2012). The potential of isothermally hardened iron with vermicular graphite. Comat 2021. Recent trends in structural materials. 21 - 22. 11. 2012, Plzeň, Czech Republic, EU.
• [12] Gumienny, G. & Kacprzyk, B. (2018). Copper in Ausferritic Compacted Graphite Iron. Archives of Foundry Engineering. 18(1), 162-166. DOI 10.24425/118831.
• [13] Pytel, A., Gazda, A. (2014) Evaluation of selected properties in austempered vermicular cast iron (AVCI). Transactions of Foundry Research Institute. LIV(4), 23-31. DOI: 10.7356/iod.2014.18.
• [14] Andršová, Z., Kejzlar, P., Švec, M. & Skrbek, B. (2017). The effect of heat treatment on the structure and mechanical properties of austempered iron with vermicular graphite. Materials Science Forum. 891, 242-248. doi.org/10.4028/www.scientific.net/MSF.891.242.
• [15] Kazazi, A., Montazeri, S.M. & Boutorabi, S.M.A. (2020). The austempering kinetics, microstructural development, and processing window in the austempered, Fe-3.2C-4.8Al compacted graphite cast iron. Iranian Journal of Materials Science and Engineering. 17(4), 46-54. DOI: 10.22068/ijmse.17.4.46.
• [16] Jakubus, A., Kostrzewa, J., Ociepa, E. (2021). The influence of parameters of heat treatment on the microstructure and strength
• properties of the ADI and the AVGI irons. METAL 2021, 30th Anniversary International Conference on Metallurgy and Materials. May 26 - 28, 2021, Brno, Czech Republic, EU (pp.34-39). doi.org/10.37904/metal.2021.4082.
• [17] Podrzucki, C. (1991). Cast iron. Structure, properties, applications. vol. 1 and 2, Cracow: Ed. ZG STOP. (in Polish).
• [18] Soiński, M.S. & Mierzwa, P. (2011). Effectiveness of cast iron vermicularization including ‘conditioning’ of the alloy. Archives of Foundry Engineering. 11(2), 133-138.
• [19] Warchala, T. (1995). Metallurgy and iron founding. Part 2 Cast iron technology. Ed. Czestochowa University of Technology.
• [20] Mierzwa, P. & Soiński, M.S. (2010). The effect of thermal treatment on the mechanical properties of vermicular cast iron. Archives of Foundry Engineering. 10(spec.1), 99-102.
• [21] Mierzwa, P., Soiński, M.S. (2012). Austempered cast iron with vermicular graphite. 70th World Foundry Congress (WFC 2012): Monterrey, Mexico, April 2012, (pp. 25-27).
• [22] Mierzwa, P. & Soiński, M.S. (2014). Austempered cast iron with vermicular graphite. Foundry Trade Journal International. 188(3713), April 2014, 96-98.
• [23] Polish Standard PN-EN 1563, Founding. Spheroidal graphite cast iron, (2000).
• [24] Soiński, M.S. (1980). Application of shape measurement of graphite precipitates in cast iron in optimising the spheroidizing process. Acta Stereologica. 5(2), 311-317.

Uwagi

Opracowanie rekordu ze środków MNiSW, umowa Nr 461252 w ramach programu "Społeczna odpowiedzialność nauki" - moduł: Popularyzacja nauki i promocja sportu (2021).