Influence of long-term operation on the properties of main gas pipeline steels. A review

Underground pipelines during operation are affected by mechanical and corrosive factors. The susceptibility of cathodically protected pipe to hydrogen degradation increases, which contributes to stress-corrosion cracking. It is believed that the main factor in pipeline steels degradation is deformation aging, which increases strength and reduces plasticity. Volume microdamages also develop in long-time exploited steels. But in many cases, the base metal and welded joints of long-term operated pipelines retain satisfactory performance. Due to the high value of viscosity and plasticity of the metal in an as-received state, the metal state of long-term operated gas pipelines can be considered satisfactory.