CO₂ CORROSION RESISTANCE OF COMMON Cr13 STEEL UNDER HIGH TEMPERATURE AND HIGH PRESSURE CONDITIONS

The carbon dioxide corrosion experiments of ordinary Cr13 steel at high temperature and high pressure were performed in the simulated environment of Daqing oil field.The morphology and chemical composition of corrosion product films were analyzed by means of SEM,EDS and XPS.At three experimental temperatures,corrosion modes of Cr13 steel in liquid and gas phases were all uniform corrosion.The major components of the corrosion films were qualitatively FeCO3 and amorphous compound Cr(OH)3.At the temperatures of 85 ℃ and 110 ℃,the corrosion rate of Cr13 steel in liquid phase was moderate.A puce and thin film was formed on the surface.The film with fine grains was flat and uniform.The corrosion rate adjoined to the lower limit of serious corrosion and upper limit of moderate corrosion at 170 ℃.The processes of corrosion in liquid and gas phases were similar,and belonged to moderate corrosion.The grains of the corrosion products were big and anomalistic.