The effect of TaC on grains and packets coarsening in the reduced activation ferritic/martensitic （RAFM） steels was investigated. It was found that the combined effect of the austenitizing temperature and heating rate resulted in the heterogeneous austenite grain growth. When the austenitizing temperature was raised above 1 423 K, the TaC particles disappeared, and the homogenous grains abruptly increased. The thermodynamic model for dissolution of TaC particles during austenitizing was applied to interpret the results.
The effect of smelting processes on mechanical properties and microstructure of reduced activation ferritic steels was studied.Creep properties and impact toughness of reduced activation ferritic steels were obviously improved by vacuum induction melting followed by consumable electrode remelting process in comparison with the conventional vacuum induction melting process.The difference of impact toughness and creep properties between both steels mainly depended on the aspect ratio and mean size of precipitates.Decreasing the aspect ratio of carbides makes development of a shear band more difficult , which could increase impact energy and creep resistance.
KANG Wen-yiZHANG ChiFAN Nian-qingXIA Zhi-xinWANG Ping-huaiCHEN Ji-ming
