X80钢焊接接头在酸性模拟液中的电化学腐蚀

采用电化学测试、金相显微镜观察,研究了X80管线钢及其焊缝组织在酸性模拟液中的电化学腐蚀行为.结果表明:X80管线钢母材的显微组织主要为针状铁素体,整体上看母材的组织较为均匀、细小,位向大致呈带状分布.焊缝的显微组织由先共析铁素体、针状铁素体和珠光体组成,焊缝的晶粒大小不均匀,整体上比母材组织粗大.在酸性模拟液中,X8...

Electrochemical Corrosion of Welded XSO Pipeline Steel in Simulated Acid Soil Solution

The corrosion behavior of X80pipeline steel in simulated solution of acid soil was investigated using electrochemical measurement and metalloscope.The results show that the microstructure of the base metal is acicular ferrite,the microstructure is uniform and tiny,the distribution is parallel.The microstructure of the weld joint of X80pipeline steel is characterized by proeutectoid ferrite,acicular ferrite and pearlite,the microstructure is uneven and bigger than base metal.No active-passive transition region is found in polarization curves of both base metal and weld joint.Both corrosion potential and charge transfer resistance of weld joint is lower than the base metal,whereas corrosive current density of the weld joint is greater than the base metal,which indicates that weld joint has a greater tendency to corrosion.The diffusion index of base metal is larger in equivalent circuit,and the corrosion produce film is denser.Corrosion resistance of the weld joint of X80 pipeline steel is lower than the base metal,due to differences in microstructure.