Tube manufacturing trials by different routes in 9CrW-ODS martensitic steels

In the collaboration work between JNC and CEA-Saclay, JNC and CEA independently manufactured ODS martensitic cladding tubes by their own fabrication routes. Manufacturing started from the same hollow shape mother tubes with a composition of 9Cr–2W–0.1Ti–0.24Y2O3. The HPTR cold-rolling process was used by both JNC and CEA, but the applied fabrication routes included different cross-section reduction ratios, number of passes and intermediate heat treatments. The manufactured claddings exhibited an isotropic grain structure and equivalent tensile strength in the longitudinal and transverse directions. Even though different cross-section reduction ratios and intermediate annealing treatments were used, both cladding tubes manufactured by JNC and CEA showed similar levels of tensile and internal creep rupture strength.