Discussion on ammonia pipeline leaks
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Our plant’s ammonia pipelines are experiencing severe leaks, which mostly occur at the welds and within 2 cm of those welds. Over time, more and more leakage points have appeared, and the severity of these leaks is increasing. (It is not due to welding quality.) Regarding the leaks in the ammonia pipeline, I have two questions: 1. Carbon steel is commonly used in the design of ammonia pipelines and ammonia tanks, which indicates that ammonia causes little corrosion to carbon steel; then why do leaks occur? 2. Why can some pipelines or tanks made of ammonia solution be used for many years, while others can only be used for a few years?
Ammonia solution may have caused stress corrosion in the carbon steel pipes; no heat treatment was carried out after welding, which led to stress corrosion cracking at the welds. For reference