Time-temperature-precipitation diagrams of carbide evolution in low alloy steels

Abstract Previously published time–temperature–precipitation diagrams showing carbide evolution were modified with the use of additional experimental data. The same low alloy steels as investigated originally were annealed at 793 and 873 K for 3000 and 10,000 h which, compared to the longest annealing time in the previous investigation of 1000 h, brings the system closer to equilibrium. Carbides extracted into carbon replicas were characterised by transmission electron microscopy, including electron diffraction and energy dispersive X-ray spectroscopy. The results of the additional experiment presented in the modified diagrams provide more information about the evolution and stability of M 3 C, M 2 C, M 7 C 3 , M 23 C 6 , M 6 C and MC in the investigated steels.