engleski

Failure of steel pipes for hot air supply

This work presents the results of the microstructural, fractographic and X-ray diffraction (XRD) analysis of heat-resistant austenitic stainless steel (AISI 310S). The analysis was performed on steel pipes after long life application in the field of hot air supply (between 2 and 3 years) at temperatures ranging from 600 to 650°C. The OM, SEM and XRD results showed that the microstructure consisted of sigma phase and carbides sporadically precipitated in an austenitic matrix impoverished in chromium. The analysis further found that the composition of sigma phase was 45.5%Cr-34.8%Fe-9.5%Ni-5.5%Si (wt. %) at any point in the analysed steel. Also, the precipitation of sigma phase at grain boundaries in the analysed steel may involve the austenite- M23C6-sigma mechanism. The fracture surface of the steel after long life application was transgranular brittle with cleavage morphology.

failure ; heat-resistant austenitic stainless steel ; microstructure ; fractography ; sigma phase

Glavni autor: Mirko Gojić