Effect of microstructure on creep and creep-fatigue strength in 316FR stainless steel

永江 勇二; 佐藤 健一郎*; 中馬 康晴*

no journal, , 

Reliability used for nuclear power plants is important issue, because the component is no replaceable in long term. 316FR steel is a candidate as structural material used at high temperature in fast reactors. Although safety margins are considered in the design, it is important to maintain or improve the reliability. 316FR steel has low carbon less than 0.020% and added nitrogen to improve creep and creep-fatigue strength. The requirement of 316FR steel is specified in the Japan Society of Mechanical Engineers code. It is possible that a grain growth and a fluctuation of carbon content occur in manufacturing. It is well-known that grain-size affects mechanical properties. In this study, the effect of grain-size and carbon content on creep and creep-fatigue strength is summarized, and is compared with the effect for Type 304 steel.