engleski

Fracture of steel casting

Unsuitable mechanical behaviour of cast steel GS-42CrMo4 (EN) was investigated. In this paper the influence of inclusions and pouring temperature on mechanical properties of arm of carrying jaw made of cast steel GS-42 CrMo 4 (EN) was investigated. It was found out that high content of aluminium caused the formation of aluminium nitride, AlN which significantly decreased strength of casting. In the process of solidification enrichment of lamellas of AlN nitride arise on the grain boundaries. Because of low deformability of AlN nitride, initiation of fracture was possible at minimal deformation. The strength of the casting was not being raised by subsequent heat treatment. High pouring temperature and low cooling rates resulted in coarse-grained microstructure of steel casting. Coarse microstructure was not being reduced by subsequent heat treatment.

cast steel; microstructure; mechanical properties

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