| Abstract |
| This study investigated the effect of an intermediate process on the microstructure and mechanical properties of a ferritic-martensitic tube for a fuel cladding tube in a sodium-cooled fast reactor (SFR). Cold drawing and heat treatment of the HT9 tube (12Cr-1MoWV) below the tempering temperature without a normalizing process was conducted (Route 1), whereas conventional normalizing and tempering conditions were also used for a comparison (Route 2). The results showed that the microstructure gradually transformed into the work-hardened structure during the Route 1 process, maintaining higher hardness throughout the reduction step. On the other hand, the microstructure of the Route 2 process gradually turned into a tempered martensite structure, whose hardness gradually increased throughout the step. M23C6 type of precipitates were generated regardless of the manufacturing route, where the size of precipitates in the Route 1 process was controlled to keep the high temperature mechanical property. |
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| Key Words |
| metals, tempering, microstructure, hardness test, ferritic-martensitic steel |
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