Investigation of the constraint effect of the P92 steel under high temperature based on the parameter Ac and creep strain

Creep crack growth is a major failure mechanism of components working under high temperature, and the constraint effect at the crack tip has significant influence on the creep crack growth rate. In this paper, the influence of the constraint effect of P92 steel on the creep crack growth was studied based on the parameter A
_c
and the creep strain at the crack tip. The result of the finite element analysis was compared with experimental data. The study revealed that the parameter A
_c
was effective in evaluating the constraint level at the crack tip, which has a great significance in evaluating the lifetime of the defected components working under high temperature. In addition, during the propagation of creep crack growth, the area of creep strain increased quickly while the area of elastic strain decreased quickly. The plastic strain stayed nearly constant and increased very slowly. During the later stage of the steady state and the tertiary creep step, the creep strain was distributed at the full area of the crack tip region and the elastic strain had only an extremely small area left.