Numerical Simulation Analysis On Thermal Fatigue Crack Growth Characteristics Of 2.25Cr1Mo Steel

2.25Cr1Mo steel is ususlly used in chemical equipments that bear cyclic heat loads. Its thermal fatigue performances directly impacts the working status and life of these equipments. In particular, the problem that if the equipments can also be used after cracks appear is very concerned. In this paper, such a background, take 2.25Cr1Mo steel as an example, through ANSYS software with finite element method to study the thermal fatigue crack growth character. The main contents are as follows:First of all, the progress study of thermal fatigue and fatigue crack growth ,the basic theory of fatigue crack growth , the development of Finite element software in the fatigue fracture disciplines , as well as the basic theory of creep crack growth are intrduced.Second,based on the basic theories of plasticity mechanics and fracture mechanics, choose appropriate yield criteria, flow rule and strengthen law,use a suitable plastic model,set up the flat-panel model with the edge crack, simulate the stress and strain field around the crack-tip and calculate the stress intensity factor .Furthermore, substitute the calculated stress intensity factor increases into the Paris or Forman formula to get the thermal fatigue crack growth rate, draw the curve of the thermal fatigue crack growth rate changing with the crack length. Change different crack sizes and loading conditions to analyze a variety of factors that impact thermal fatigue crack growth rate. Set up in-phase and out-of-phase thermal fatigue model, analyze the difference between them.Finally, add the effects of creep factor, analyze the combined effect of thermal fatigue and creep on crack growth .