镀锌铁塔腐蚀特性及防腐寿命预测

Corrosion characteristics and anticorrosion life prediction of galvanized iron towers

  • 摘要: 为有效评估腐蚀对长期服役杆塔服役设计寿命和防腐使用寿命造成的影响,采用扫描电镜、盐雾腐蚀试验和理论分析计算的方法,研究了镀锌角钢在12~60 d的盐雾腐蚀环境中的外观形貌、腐蚀速率、腐蚀后的微观形貌和锈蚀产物类别的变化,结合Zn的大气暴晒腐蚀变化规律和腐蚀理论计算,计算了C4大气环境下镀锌角钢的盐雾试验和大气暴晒的试验加速比,合理预测了镀锌杆塔服役设计寿命和防腐使用寿命。研究结果表明:镀锌角钢经盐雾腐蚀12~60 d后其平均腐蚀速率下降较为明显,腐蚀产物Zn5(OH)6(CO32和Zn5(OH)8Cl2H2O的生成是降低镀锌角钢腐蚀速率的主要因素。镀锌杆塔在C4大气腐蚀环境下的设计使用寿命为43.0~48.5年,实际服役年限为53.2~64.7年。

     

    Abstract: In order to effectively evaluate the impact of corrosion on the design life and anti-corrosion service life of long-term service poles and towers, scanning electron microscopy, salt spray corrosion tests, and theoretical analysis calculations were used to study the changes in appearance morphology, corrosion rate, microstructure after corrosion, and types of corrosion products of galvanized angle steel in a salt spray corrosion environment for 12 to 60 days. Based on the variation law of atmospheric exposure corrosion of Zn and corrosion theory calculation, the acceleration ratio of salt spray test and atmospheric exposure test for galvanized angle steel in C4 atmospheric environment was calculated, and the service design life and anti-corrosion service life of galvanized poles and towers were reasonably predicted. The research results indicated that the average corrosion rate of galvanized angle steel decreased significantly after 12 to 60 days of salt spray corrosion. The formation of corrosion products Zn5(OH)6(CO3)2 and Zn5(OH)8Cl2H2O is the main factor that reduces the corrosion rate of galvanized angle steel. The designed service life of galvanized towers in a C4 atmospheric corrosive environment was 43.0-48.5 days, and the actual service life was 53.2-64.7 years.

     

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