低Si-12Cr耐熱鋼のクリープ破断強さと微細組織
1980 年 66 巻 1 号 p. 82-91
詳細
1980 年 66 巻 1 号 p. 82-91
The beneficial characteristic of vacuum carbon deoxidized low-Si steels, in which macro-segregation in large ingots was hardly observed, was applied to a 12Cr heat resisting steel. The studies on the microstructures and creep rupture properties for a low Si-12Cr-1.5Mo-0.2V-0.05Nb steel after various heat treatments were carried out. The creep recovery process, the precipitation characteristics of M23C6, and the dissolution and agglomeration of the fine precipitates was investigated by the aid of transmission electron microscope. Furthermore, the effects of prior tempering temperature and creep stress on the microstructures and mechanical properties were also investigated.
This steel exhibits a creep rupture strength 1.4 times higher than that of the conventional super 12Cr rotor steels. The austenitizing temperature effective for the long term creep strength was found to be in the range of 1050°C-1100°C and optimum prior tempering temperature was about 700°C.
