Selection of corrosion protective coatings for long distance pipeline

Summarizes present situation on corrosion protective coatings for long distance pipeline and characteristics of commonly used coating materials. Analyzes relations from external condition with coatings failed in the aspects of medium's corrosiveness around pipeline, environment and coating construction. Types of failed coatings are mainly: coating disbonding, rupture, puncture and distortion. Analyzes reasons of coating failure and points out that reason of disbonding relates closely with the quality of coating material, steel pipe's surface treatment and cathodic protection current; the rupture relates with soil stress, external force and material's aging; and puncture is resulted from incorrect construction or external force. Introduces and evaluates properties and characteristics of some commonly used coatings domestically and point out that coatings selected for long distance pipeline shall be proved and compared in the following four aspects based on concrete conditions: external condition, pipeline work span, engineering significance and pipeline maintenance requirement, coating quality and cost. Optimum plan is to use the coatings of relatively good properties and reasonable cost in light of pipeline's actual requirements.