Characteristics of creep deformation for 2.25Cr -1Mo were studied using the Monkman–Grant relation. A series of creep tests were conducted on 2.25Cr -1Mo at low-stress levels and at different temperatures ranging from 655 0Cto 6850C . The analysis of creep data indicates that 2.25Cr -1Mo is practically supported by Monkman-Grant relationship. Yet, this paper highlights the foremost difficulties associated with the parametric fitting techniques. The damage tolerance factor has been estimated to demonstrate its reliance on the loading conditions and to categorize the material strain concentration. It has been shown that at 55MPaand T=6850C , the tertiary creep stage is not well characterized. Also, this paper identifies a need to provide a serious consideration for an appropriate creep strength factor that would be applied to pressure vessels and to improve the criteria related to design against creep and the prevention of failure. پرونده مقاله