Mechanical properties and corrosion behavior of Cr containing pipeline steel

Based on the need for pipeline steel in the oil and gas industry of China, a novel 2% Cr pipeline steel with good matched strength and toughness was developed through a reasonable thermomechanical control process (TMCP). Its mechanical proper-ties and microstructure were studied preliminarily and the results show that the 2% Cr pipeline steel mainly containing acicular ferrite and a few polygonal ferrites has a better combination of strength and toughness. The corrosion resistance of the 2%Cr pipeline steel was evaluated in the CO₂ top-of-the-line corrosion environment in submarine wet gas pipelines which was simulated with a high temperature and high pressure condensation autoclave. Compared with traditional pipeline steel, adding 2% Cr makes obvious changes of corrosion behavior and a continuous and compact amorphous film with Cr enrichment forms, thus improving its CO₂ corrosion resistance.