Tensile properties on dissimilar welds between 11Cr-ferritic/martensitic steel and 316 stainless steel after thermal aging

Yano, Yasuhide  ; Tanno, Takashi  ; Oka, Hiroshi   ; Sekio, Yoshihiro  ; Otsuka, Satoshi   ; Kaito, Takeji ; Tachi, Yoshiaki  

Ferritic/martensitic (F/M) steels are expected to be used not only for the long-life core material of fast reactors, but also for the blanket materials of fusion reactor due to their superior swelling resistance. It is important to evaluate the mechanical properties of the dissimilar joints after thermal aging. The present study evaluated and discussed the effect on the tensile properties of EB welded dissimilar joints produced by thermal aging up to 30000 h. Most welds were overmatched for all aging conditions and ultimate tensile strength of aged WM were higher than those of aged base metals (PNC-FMS and 316SS. UTS of the WM aged at 400C was about 1.5 times higher than that of as-received WM (1100 MPa), but there was no significant change in the uniform elongation before and after aging. The Cr-rich phase were observed in a part of WM areas after thermal aging at 400 and 450C. The Cr-rich phase at 400C was finer and more homogenous than those at 450C.