Heat-to-heat variation of creep strength and long-term stability of microstructure in Grade 91 steels

Heat-to-heat variation of long-term creep strength and microstructural changes was investigated in ASME Gr. 91 steels (heat name: MGC heat and MgC heat) by focusing on the effects of minor elements. The heat-to-heat variation of creep strength was not observed at 500 °C and 550 °C. At 600 °C and 650 °C, there was no significant difference in the creep strength up to 10,000 h in the two heats. However, at 600 °C, the creep strength of the MGC...