不同静水压力下X100钢在海洋环境中腐蚀剩余寿命预测

Corrosion Residual Life Prediction of X100 Pipeline Steel in Sea Water under Different Hydrostatic Pressures

采用动电位极化曲线法,测量了静水压力1～6 MPa时X100管线钢在3.5%Na Cl海水模拟溶液中的腐蚀电流密度,并外推计算出管线钢在静水压力为7、8 MPa下的腐蚀电流密度。采用ANSYS有限元软件,对含外腐蚀缺陷的X100管线钢,在静水压力分别为5～8 MPa、腐蚀缺陷尺寸56 mm×42 mm×3.6 mm时的等效应力进行模拟,并计算出其相应静水压力下的腐蚀电流密度。依据腐蚀剩余寿命计算公式、Barlow公式和ASME-B31G准则,计算出管线钢在海水模拟环境下应力集中点的腐蚀剩余寿命。

The corrosion current density of X100 pipeline steel under hydrostatic pressure of 1-6 MPa in 3.5% NaC1 solution were measured by dynamic potention polarization curve method. The density of corrosion current at hydrostatic pressures of 7 MPa and 8 MPa were calculated by using extrapolation. The equivalent stress of X100 pipeline steel with external corrosion defects size as 56 min×42 min×3.6 mm was simulated at 5-8 MPa hydrostatic pressures by ANSYS finite element software.The corresponding corrosion current densities were calculated at different hydrostatic pressures. The corrosion residual life of the pipeline at stress concentration point in sea-water simulation environment was computed according to the formula of remaining life of corrosion, barlow formula and ASME-B31G criterion.