Thermal transient test and strength evaluation of a thick cylinder model made of Mod.9Cr-1Mo steel

改良9Cr-1Mo鋼厚肉円筒試験体による熱過渡試験と強度評価

安藤 勝訓 ; 長谷部 慎一; 小林 澄男; 笠原 直人*; 豊吉 晃*; 大前 隆広*; 江沼 康弘*

Ando, Masanori; Hasebe, Shinichi; Kobayashi, Sumio; Kasahara, Naoto*; Toyoshi, Akira*; Omae, Takahiro*; Enuma, Yasuhiro*

改良9Cr-1Mo鋼大型構造物の熱過渡における破損様式を確認するため、厚肉円筒試験体に対してナトリウムループを用いて1873サイクルの熱過渡強度試験を実施した。試験は600Cと250Cの流動ナトリウムにより実施し、それぞれ2時間及び1時間の過渡後保持時間を設けた。試験後に浸透探傷試験、走査電子顕微鏡による観察等を実施した。また有限要素法解析を実施し、クリープ疲労損傷値と観察されたき裂状況の比較検証を行った。

To verify the failure mode and assess creep-fatigue damage, a thick cylinder test model made of Mod.9Cr-1Mo steel was subjected to 1,873 cycles of accelerated thermal transient loading using a large-scale sodium loop through which liquid sodium at 600 C and 250 C flowed repeatedly, with the period of each transient being 2 h and 1 h, respectively. After completion of the test, the test model was inspected using liquid penetrant testing. Observations using a scanning electron microscope and hardness testing were then performed to characterize creep-fatigue damage in the structural model subjected to cyclic thermal transient loading in a sodium environment. Finite element analysis were performed to evaluate the relationship between creep-fatigue damage and the observed crack conditions.