A Proposal of a conversion method between small punch creep properties and uniaxial ones of Mod.9Cr-1Mo steel at the operating temperature of fast reactors

Yamashita, Hayato ; Onizawa, Takashi  ; Takaya, Shigeru  ; Enuma, Yasuhiro  ; Wakai, Takashi ; Kato, Shoichi ; Suzuki, Akihiro*

This study proposes an appropriate method to convert the load parameter in small punch creep (SPC) tests to that in uniaxial creep tests for Mod.9Cr-1Mo steel at operating temperature of future fast reactors. It is impossible to simply compare the results of SPC tests to those of uniaxial creep tests, because the load parameters in those creep tests are load and stress, respectively. Conventionally, load/stress conversion coefficient (F/) has been employed to compare the results of SPC and uniaxial creep tests. Though the applicability of F/ has been demonstrated in the temperature region considerably higher than 550C that is the operating temperature of future fast reactors, the applicability has not been demonstrated at 550C. Therefore, this paper studies an appropriate method to obtain F/. F/ calculated from finite element analysis (FEA) and that based on fracture ductility was too small to convert SPC results. In contrast, it was clarified that conversion was possible using F/ based on Arrhenius-type equation.