耐熱鋳鋼のミクロ組織と高温特性に及ぼす鋳込温度の影響

抄録

  Investigations were conducted on the microstructure and elevated temperature properties of SCH13A austenitic heat resistant cast steel which was prepared by the sand mold casting process with self-hardening alkaline phenol binder under the pouring temperatures of 1763K and 1823K. Thermal shock and creep rupture tests were carried out for the evaluation of elevated temperature properties. Results revealed that thermal shock resistance as well as creep rupture time significantly improved with increasing pouring temperature. This can be explained by the crystallization behavior of primary carbides after solidification in terms of their morphology, amount as well as thermal stabilization. The effects of secondary carbides on the suppression of crack propagation emitted under thermal shock and / or creep environment were smaller than primary carbides. Additionally, the precipitated volume of sigma phase which causes high temperature brittleness decreased with increasing pouring temperature.