Conclusions
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1.
Cracks in castings of steel 27KhGSNL result from breaking along the boundaries of dendrite colonies or primary austenite grains, brittle fracture along ferrite located in primary austenite grain boundaries, intercrystalline fracture along definite planes, and transcrystalline fracture.
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2.
Fine fractographic analysis of the oxidized surfaces of cracks is possible with the scanning electron microscope.
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3.
To reduce the tendency of castings to crack it is necessary to increase the quantity of austenite-forming elements and reduce the amount of ferrite-forming elements and increase the disperisity of the dendritic structure by increasing the cooling rate of the liquid steel.
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Additional information
Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 3, pp. 58–60, March, 1977.
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Osnovin, V.A., Shaporenko, S.U. & Lapina, É.Y. The nature of cracks in castings of steel 27KhGSNL. Met Sci Heat Treat 19, 225–227 (1977). https://doi.org/10.1007/BF01167007
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DOI: https://doi.org/10.1007/BF01167007