AN INVESTIGATION OF FRACTURE TOUGHNESSOF CO2 CORROSION SCALE ON PIPELINE STEEL

摘要

In the present work, the influences of scale forming temperature, CO2 partial pressure andrnsolution flow rate on CO2 corrosion scale formed on X65 pipeline steel were investigated, and thernfracture toughness of the scale KIC and the interface fracture toughness K′IC between the scale andrnsubstrate were evaluated by means of indentation and adhesion tensile tests, respectively. Resultsrnindicate that crystalline FeCO3 dominated the scale formed under various test conditions, except for thernone formed at 0.1MPa CO2 partial pressure which also contained CaCO3 and MgCO3. Increasing thernscale forming temperature caused an increase in the interface fracture toughness K′IC but a decrease inrnthe fracture toughness KIC of the scale. At 0.5m/s flow rate, the scale exhibited the lowest fracturerntoughness KIC, however, the interface fracture toughness K′IC decreased with increasing the flow rate.rnThe CO2 partial pressure had no obvious influence on both K′IC and KIC.