Objective: To explore the failure cause of buried pipelines in an oil and gas station. Method: The chemical elements and metallographic structure of the failed pipes were analyzed to evaluate whether the pipe body meets the requirements of relevant standards; the morphology and composition of the corrosion products were analyzed to discover the cause of corrosion. Result: The metal surface was rough and full of pitting pits with severe localized corrosion, and no crack of the metallic matrix was found. The corrosion products mainly contain Fe_(3)O_(4)and a small amount of FeCO_(3), wherein Fe_(3)O_(4)is the secondary corrosion product formed in the air, and FeCO_(3)is the corrosion product of CO_(2)in an oil and gas environment. The surface of the corroded product is loose in structure and easy to peel off, leading to further corrosion of the metallic matrix. Conclusion: The pipeline corrosion failure was caused by CO_(2)-induced corrosion failure in the medium.
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