软管环形域空隙率对铠装层金属腐蚀行为的影响研究

Study about the Influence of the Porosity in Annulus of Flexible Pipe for Corrosion of Armor Mental Material

海洋挠性软管是一种用于水下油气水的集输的多层复合管道。其内层与外层聚合物材料之间的区域被称为环形域,处于环形域内的铠装层金属材料通常为碳钢。内管输送介质中水蒸气、CO 2等腐蚀介质会渗透至环形域内造成金属材料的腐蚀。管道在设计阶段需要对管道进行腐蚀性能评价,以验证材料在整个寿命周期末端的承载能力仍满足管体设计要求[1]。根据ASTM G111标准[2],常规的腐蚀试验需要考虑温度、压力、试验介质、pH值等,由于软管环形域空间极低的孔隙率,在有限腐蚀介质中存在大量的金属材料,所以常规的试验方法不能真实地反应软管环形域条件下的腐蚀情况。本文目的在于探究海洋挠性管道环形域金属材料的评价方法以及研究铠装层金属材料的腐蚀行为,并分析材料的腐蚀趋势。

The marine flexible pipe is a multi-layer pipeline which used for gathering and transporting oil,gas and water under seawater.The area between the inner and the outer polymer material is called the annulus,and the metal material of the armor layer in the annulus is usually carbon steel.Corrosive media such as water vapor,CO 2 in the transport medium of the inner pipe will penetrate into the annular area and cause corrosion of metal materials.During the design stage of the pipeline,the corrosion performance of the pipeline needs to be evaluated to verify that the corrosion resistance of the material at the end of the entire lifetime still meets the design requirements of the pipe body.According to the ASTM G111 standard,the normal corrosion tests need to consider temperature,pressure,test medium,pH,etc,but due to the low porosity in the annulus of flexible pipe,there are a large number of metallic materials in the limited corrosive medium,so the normal test method cannot truly reflect the corrosion in the annulus of flexible pipe.The purpose of this article is to explore the evaluation methods of metallic materials in the annulus of marine flexible pipe,to study the corrosion behavior of metallic materials of armor layers,and to analyze the corrosion trends of materials.