Creep And Numerical Simulation Of P92 Steel Pipe Elbow

With the increase of the parameters and capacity of thermal power units,the safety of the unit's operation is becoming more and more serious,and the creep of the pipeline under high temperature and high pressure is a main factor of the failure of the equipment.The elbow plays a vital role in the power plant in the pipeline,while it's more prone to failure.Therefore,to study the creep behavior of pipe bend under conditions of biaxial stress and high temperature is of great significance to the design and life management of power plant pipeline and to establish high temperature structural integrity standard.This paper designs and finishes creep test of full size pipe bend,achieves the sustained experiments of elbow under bending moment loads at 650?.And it layouts an acquisition scheme of measuring point for observing deformation of different ageing process and microstructure of P92 steel,in order to study the multiaxial creep behavior and the influence of hardness and stress.Meanwhile,the paper selects a creep constitutive model for finite element analysis,the development of ANSYS software with damage to simulate the whole stage of creep,exploring the relationship of stress distributions,damage and creep of elbow.The results show that the existence of damage will change the stress distribution,but the impact on the elbow creep is small,and the paper analyses the main failure position and the life of the elbow.Taking the change of wall thickness of the elbow at manufacturing process into account,simulation and analysis of elbow creep about the difference between equal thickness and unequal thickness is managed,and it also discusses the influence of the actual situation of wall thickness on elbow creep.It's found that the change of wall thickness will change gradient distribution of the stress,but will not cause the change of speed of damage development.By comparing the experimental results with the simulation results,the validity of creep model and the conclusion about effect of multi axis stress state on the creep obtained by notch test is verified,and it yet shows that the simulation analysis in this paper has certain reference and reliability.