Study On The Equivalent Creep Rate And Life Of 316L Stainless Steel Plate Fin Structure

The plate fin heat exchanger in the high temperature gas cooled reactor has the characteristics of compact structure and high efficiency of heat transfer.Plate fin structure is the core component of plate fin heat exchangers,and its material is usually 316 L stainless steel.The plate fin structure of high temperature gas cooled reactor works at high temperature and high pressure,and its main failure mode is creep failure.In order to predict the deformation and evaluation life,this paper studies the equivalent creep rate and life of the plate fin structure under high temperature creep,based on theoretical deduction,simulation calculation and experimental analysis.The main contents and conclusions of the study are as follows:(1)The formula of the equivalent creep rate of plate fin structure is derived based on the equivalent theory,and the correctness of the formula is verified by the creep test of the plate fin structure and the finite element simulation.The effect of the structure size on the equivalent creep rate shows that the equivalent creep rate decreases with the increase of fin thickness or fin angle,and the equivalent creep rate increases with the increase of fin width or fin length,and the creep rate is constant with the increase of the length of the structure.(2)Through the creep test of base metal,the material parameters needed for the simulation of high temperature creep are obtained.The load parameters needed for the simulation of high temperature creep are determined by simulating the short time high temperature tensile strength of plate fin structures with different structural dimensions.It is found that the elastic limit of plate fin structure increases with the increase of fin thickness or fin angle,and the elastic limit of plate fin structure decreases with the increase of fin width or structure length,and the elastic limit of plate fin structure increases with the increase of fin length.(3)Based on the formula of the equivalent creep rate,the formula for the creep life of the plate fin structure is derived,and the correctness of the formula is verified by the stress concentration method and the creep damage method.In the process of derivation and verification of the creep life formula,the formula of the stress concentration coefficient of the plate fin structure is obtained,and the conclusion that the stress concentration coefficient is only related to the structural angle is obtained.The effect of structure size on creep life was analyzed.It was found that the creep life of plate fin structure increased sharply with the increase of fin thickness,and the creep life of plate fin structure decreased with the increase of fin angle or fin width or fin length.