Creep property evaluation of a 2.25Cr–1Mo low alloy steel

The creep properties of a 2.25Cr–1Mo steel which was quenched from 1253 K and tempered at 923 K were examined under different engineering stresses (225–325 MPa) at temperatures ranging from 773 to 898 K. The creep behavior followed the temperature-compensated power law and Monkman–Grant equations. In the temperature-compensated power law equation, the apparent activation energy and stress exponent for creep were determined as approximately 380 kJ/mol and 10, respectively. In the Monkman–Grant relation, the values of m and C were determined as around 1.016 and 0.0528, respectively, when the minimum creep rate was in h−1 and the rupture time in h. In all conditions considered the specimens all presented ductile fracture with a rupture strain over 29%. There existed a minimum value of rupture strain at 250 MPa as the rupture strain varies with applied stress from 225 to 325 MPa when testing at 823 K, which could be caused by recrystallization in the fracture tip areas of the material.