Experimental and thermodynamic studies of phase transformations in Cr-V low alloy steels

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 335; no. 1-2; pp. 290 - 297
• Main Authors: Homolova, V, Janovec, J, Kroupa, A
• Format: Journal Article
• Language: English
• Published: 01.01.2003
• ISSN: 0921-5093

Phase transformations in three Cr-V low alloy steels at 773 and 853 K were studied experimentally in a transmission electron microscope (TEM). The theoretical calculations were carried out for ternary Fe-Cr-C and quaternary Fe-Cr-V-C systems corresponding to the investigated steels. The calculations of phase equilibria were performed using the thermodynamic database program THERMO-CALC. M sub 3 C in 1Cr and 1Cr-0.3V steels, M sub 7 C sub 3 in 1Cr-0.3V steel, and MC in 1Cr-0.3V and 1Cr-0.5V steels were identified. The formation of M sub 3 C precedes the formation of M sub 7 C sub 3. The M sub 7 C sub 3 carbide in all investigated steels and the MC carbide in steels containing vanadium were determined by THERMO-CALC as equilibrium phases. The comparison of experimental and computational results indicates that the investigated steels have not achieved equilibrium even after aging for 5000 h at 773 and 853 K.