Mechanical Properties and Microstructural Evolution of T23 Heat-resistant Steel during Aging at 873K

摘要

In this paper, the mechanical properties and microstructural evolution of T23 (2.25Cr-1.6W-V-Nb) heat-resistant steel during aging at 873K were investigated. The results show that the mechanical property degradation of T23 is related to the microstructural evolution during aging. There is an obvious decrease in yield strength and tensile strength when the aging time ranges from 0 to l000h and 5000 to lOOOOh. In the short-term region, the coarsening of M_(23)C_6 carbide results in the significant decrease in the yield strength and tensile strength, whereas for long-term aging the transformation of granular bainitic ferrite plays a main role. Compared with the as-supplied materials, the impact toughness of T23 aged for l0000h decreases by 20%, which results from the coarsening of M_(23)C_6 and the coalescence of bainitic ferrite laths.