Naslov
Effect of inoculation, cooling rate and charge composition on gray iron microstructure

Autori
Hirš, Ana-Marija ; Glavaš, Zoran ; Štrkalj, Anita

Vrsta, podvrsta i kategorija rada
Radovi u zbornicima skupova, cjeloviti rad (in extenso), znanstveni

Izvornik
Proceedings book of the VIIIth International Scientific Conference - Material Science- Nonequilibrium Phase Transformations / - Varna : Scientific technical union of mechanical engineering Industry - 4.0, 2022, 23-26

Skup
8th International Scientific Conference "Material Science. Nonequilibrium Phase Transformations"

Mjesto i datum
Varna, Bugarska, 05.09.2022. - 08.09.2022

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
gray iron microstructure ; inoculation ; cooling rate ; charge composition

Sažetak
This paper analyses the effect of different charge compositions for melt production, cooling rate (i.e. casting wall thickness) and inoculation on the gray iron microstructure. In this study, three gray iron melts were produced that had almost the same chemical composition. The proportions of steel scrap (SS), pig iron (PI), gray iron return (GIR) and SiC in charge were as follows: melt 1 (10 % SS, 39.4 % PI, 49.2 % GIR, 0.6 % SiC), melt 2 (38.8 % SS, 9.9 % PI, 47.9 % GIR, 1.6 % SiC) and melt 3 (0 % SS, 0 % PI, 99.2 % GIR, 0.06 % SiC). One uninoculated and one inoculated stepped test casting with walls thicknesses of 5, 10, 20, 45 and 65 mm was casted from each melt. The inoculant was added in the melt stream during pouring in the mould in an amount of 0.23 wt.%. The type, size and distribution of graphite flakes in the analysed walls did not significantly depend on the charge compositions. The structure of the metal matrix, carbides precipitation and type, size and distribution of graphite flakes were largely dependent on the wall thickness. As the wall thickness increased, the cooling rate decreased and the type of graphite flakes changed, from D and E through B to A type. Carbide formation has occurred in the edge region of the 5 mm thick walls. With the decrease of the cooling rate and increasing the proportion of D and E type graphite flakes, the ferrite content in the metal matrix increased. The carbide content in the edge region of the 5 mm thick walls was significantly reduced by inoculation. Inoculation increased the proportion of A type graphite flakes in the middle of 5 mm thick wall and in walls with a thickness from 10 to 65 mm. In addition, inoculation significantly reduced the proportion of B, D and E type graphite flakes or were completely eliminated. Wall thickness has affected this effect.

Izvorni jezik
Engleski

Znanstvena područja
Metalurgija

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