Residual Ferrite Control of 9Cr ODS Steels by Tailoring Reverse Austenite Transformation

By tailoring the reverse austenite transformation behavior of 9Cr oxide dispersion strengthened (ODS) ferritic/martensitic steels, the residual ferrite in ODS steels can be controlled. The reverse austenite transformation behavior of ODS steels is closely related to the initial microstructure conditions prior to austenite transformation. For the spark plasma sintered steels, both the amount and size of residual ferrite decrease with increasing heating rate. Nevertheless, high heating rate will increase the amount and size of residual ferrite in annealed ODS steels. As an isothermal treatment is performed at temperatures above Ac-1, lower isothermal temperature has a more evident effect on the ferrite distribution in spark plasma sintered steels than that in annealed ones.

Automated summary

The reverse austenite transformation behavior of 9Cr ODS steels can be controlled by tailoring the heating rate and isothermal treatment, affecting the amount and size of residual ferrite in the steels.