Study on Corrosion Behavior of L360 Pipeline Steel and Weld Joint in CO2/H2S Solutions
|School||Beijing University of Chemical Technology|
|Course||Materials Science and Engineering|
|Keywords||L360 pipeline steel Welded joints Microstructure CO2 corrosion H2S corrosion Temperature Cl ~ - concentration Polarization curves|
With the continuous development of the oil and gas industry , containing CO2, H2S and other strong corrosive medium will pose serious challenges to the development of oil and gas fields . The simulated oil field environmental conditions , using weight loss method , electrochemical methods and surface analytical tools , more systematic research L360 pipeline steel welding the corrosion behavior joints in saturated CO2/H2S solution and its different factors . This paper examines the status and distribution of the L360 pipeline steel welded joints on the thermal history metallographic organization , the hardness test , and each heat experienced regional independent micro electrochemical performance testing and research . The results showed that the L360 pipeline steel welded joints micro microstructure have different structures and characteristics . Solution to simulate corrosion electrochemical test the welded joints each micro Ecorr, icorr different , constitute a multi- electrode system , in which the heat -affected zone Yi suffered a priority corrosion dissolved . Adding corrosion inhibitors can effectively inhibit the corrosion of welding . In addition , from a practical environment examined temperature , corrosion time , solution pH, and gas-liquid equal factors L360 pipeline steel in the impact of the the simulated oilfield the deep aqueous solution in the CO2/H2S corrosion , use of EDS , SEM and XRD corrosion products the observation and analysis . The results show that the great influence of temperature on the corrosion rate , corrosion rate first increases and then decreases as the temperature rises , reaches a maximum of 50 ° C , the corrosion products generated to FeS1 -x ; reduce the pH of the solution , the increase in Cl-concentration in the solution L360 steel corrosion exacerbated . View from the surface of the corrosion products , the gas corrosion product surface porosity , and a little corrosion pits appear dense liquid corrosion products , no pitting and appear .