ASME B 31G规范把复杂的腐蚀坑剖面曲线简化成矩形或抛物线投影,是造成ASME B 31G规范预测结果出现保守和不稳定性的重要原因。文章采用非线性有限元方法,综合分析了腐蚀坑剖面面积和腐蚀坑形状系数对腐蚀管道失效压力的影响,提出一种...ASME B 31G规范把复杂的腐蚀坑剖面曲线简化成矩形或抛物线投影,是造成ASME B 31G规范预测结果出现保守和不稳定性的重要原因。文章采用非线性有限元方法,综合分析了腐蚀坑剖面面积和腐蚀坑形状系数对腐蚀管道失效压力的影响,提出一种新的以腐蚀坑剖面面积和腐蚀坑形状系数描述腐蚀坑形貌的B31G修正公式,实际算例表明新提出的B31G修正公式的预测结果保守性低,预测误差稳定。展开更多
The electrochemical features of commercial airfrarne material, Al alloy LY12, in 0.349mol/L neutral sodium chloride (NaCl) and sodium sulfate (NazSO^) solutions were investigated by electrochemical impedance spectrosc...The electrochemical features of commercial airfrarne material, Al alloy LY12, in 0.349mol/L neutral sodium chloride (NaCl) and sodium sulfate (NazSO^) solutions were investigated by electrochemical impedance spectroscopy (EIS) and potentiody-namic polarization techniques. The microstructure of the as-tested samples was studied by scanning electron microscopy. The results show that the Nyquist plots of LY12 at different immersion time displayed different features, indicating that the Cl- ions elevate the corrosion rate and inhibit the repassivation of a metastable pit. It also shows that the corrosion product of LY12 formed in SO42- solution isn't easy to dissolve, and it will cover the surface of working electrode in the electrolyte. SEM images indicate that the corrosion apparent area and pit number of LY12 in NaCl solution are greater than that in Na2SO4 solution.展开更多
文摘ASME B 31G规范把复杂的腐蚀坑剖面曲线简化成矩形或抛物线投影,是造成ASME B 31G规范预测结果出现保守和不稳定性的重要原因。文章采用非线性有限元方法,综合分析了腐蚀坑剖面面积和腐蚀坑形状系数对腐蚀管道失效压力的影响,提出一种新的以腐蚀坑剖面面积和腐蚀坑形状系数描述腐蚀坑形貌的B31G修正公式,实际算例表明新提出的B31G修正公式的预测结果保守性低,预测误差稳定。
基金The authors wish to acknowledge the financial supports of the National Key Basic Research Foundation of China(Grant No.G1999065001)the National Natural Science Foundation of China(Grant No.50071054)the State Key Laboratory for Corrosion and Protection of Metals(China).
文摘The electrochemical features of commercial airfrarne material, Al alloy LY12, in 0.349mol/L neutral sodium chloride (NaCl) and sodium sulfate (NazSO^) solutions were investigated by electrochemical impedance spectroscopy (EIS) and potentiody-namic polarization techniques. The microstructure of the as-tested samples was studied by scanning electron microscopy. The results show that the Nyquist plots of LY12 at different immersion time displayed different features, indicating that the Cl- ions elevate the corrosion rate and inhibit the repassivation of a metastable pit. It also shows that the corrosion product of LY12 formed in SO42- solution isn't easy to dissolve, and it will cover the surface of working electrode in the electrolyte. SEM images indicate that the corrosion apparent area and pit number of LY12 in NaCl solution are greater than that in Na2SO4 solution.
