a bainite 2.25Cr-1Mo steel at 455oC
Hao
Jiang1, Oluwadamilola Olaoluwa
Ogunmola1,
Zizhen Zhao2, Xu Chen1*
1School of Chemical Engineering & Technology, Tianjin
University, Tianjin 300072, China
2School of Mechanical & Automotive Engineering, Qilu
University of Technology (Shandong Academy of Sciences), Jinan 250353,
China
*Corresponding author:xchen@tju.edu.cn
Abstract:Uniaxial
static and cyclic creep tests are carried out on a bainite
2.25Cr-1Mo
steel at 455°C. The dependence of cyclic response on varied unloading
conditions is investigated, with unloading rates from 0.6 MPa/s to 39
MPa/s and the valley stress duration from 0 to 30 min. Fracture surfaces
of each specimen are analysed by using a scanning electron microscopy,
and a systematic classification of strain components under cyclic creep
is proposed to determine the actual damage. The results indicate that,
the fracture modes under static and cyclic creep conditions both have
ductile features. Due to the effect of
anelastic strain recovery, the
strain accumulation rate under cyclic creep is significantly retarded as
compared with static creep, and the unloading conditions apparently
influence the behaviour of anelastic strain recovery. Moreover,
a life prediction method for
cyclic creep tests based on mean actual strain deducted recovery strain
is proposed.
Keywords: 2.25Cr-1Mo steel;
static creep; cyclic creep; unloading conditions; anelastic stain
recovery