Effect of Temperature on Microstructure and Mechanical Properties of CO₂ Corrosion Scale on N80 Sreel

CO2 corrosion test was performed in a rotary autoclave at high temperature and high pressure in an aggressive solution simulating the stratum water in oil field.The effect of temperature on CO2 corrosion behavior of N80 steel was investigated.In the temperature range from 65℃ to 90℃,the composition of CO2 corrosion scale formed on N80 steel surface was(Fe,Ca)CO3,while it changed into(Fe,Ca,Mg)CO3 and Fe3O4 when the temperature increased to 115℃.Fracture toughness of the corrosion scale and the adhesion strength between the scale and substrate increased with increasing temperature.