Original scientific paper

https://doi.org/10.17559/TV-20180313125057

Microstructure and Tribological Properties of Spheroidal Graphite Cast Irons with Nanoadditives

Julieta Kaleicheva orcid.org/0000-0002-7191-9335 ; Technical University of Sofia, Faculty of Industrial Technology, 8 Kl. Ohridski blvd., 1000 Sofia, Bulgaria
Valentin Mishev ; Technical University of Sofia, Faculty of Industrial Technology, 8 Kl. Ohridski blvd., 1000 Sofia, Bulgaria
Vlatko Marušić ; Mechanical Engineering Faculty in Slavonski Brod, University of Josip Juraj Strossmayer in Osijek, Trg Ivane Brlić-Mažuranić 2, 35000 Slavonski Brod, Croatia

Abstract

In this paper metallographic, mechanical and tribological tests of spheroidal graphite cast iron with applied nanosized additives of titanium nitride + titanium carbonitride (TiN + TiCN), titanium nitride TiN and cubic boron nitride cBN are perfomed. With the aim to achieve upper bainite structure, samples of spheroidal graphite cast iron are put under austhempering at the following conditions: heating at 900 °С, 1 h and isothermal retention at 380 °С, 2 h. In order to achieve the wear resistance, the resulting structure of the upper bainite has similar properties as martensitic structure, but with improved toughness. By X-ray analysis before and after the wear resistance test, the share of retained austenite was reduced in samples with applied nanosized additives compared to the samples of spheroidal graphite cast iron that were tested without the application of nanosized additives. Based on the analysis of the test results it was concluded that the samples with applied nanosized additives increased wear resistance compared to the samples that were tested without the application of nanosized additives.

Keywords

austempered ductile iron; hardness; microstructure; nanoadditives; upper bainite; wear resistance

Hrčak ID:

223305

URI

https://hrcak.srce.hr/223305

Publication date:

25.7.2019.

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