The effect of carbon on 2.25 Cr-1 Mo steel: (II). Creep—rupture properties

The creep-rupture properties of normalized-and-tempered 2.25 Cr-1 Mo steel with 0.009, 0.030, 0.120, and 0.135 wt % C were determined at 454, 510, and 565°C; the results show an effect of carbon that depends on temperature. At all three temperatures, the 0.120 and 0.135 wt % C steels have similar strengths, and at 565°C are considerably stronger than the 0.009 and 0.030 wt % C steels, which also have similar strengths. At 454 and 510°C, however, the properties for the 0.030 wt % C steel are superior to those of the 0.009 wt % C steel and approach those for the 0.120 and 0.135 wt % C steels. These observations can be explained in terms of the type of carbide precipitation reactions that occur in 2.25 Cr-1 Mo steel.