Study on Gradual Change of Corrosion Behaviors in 13MnNiMoR Steel Weld Joint Serviced in EO Reactor

This paper will focus on the gradual change of corrosion behaviors among different zone metal of 13MnNiMoR steel weld joint in the EO reactor service environment. Metallographic analysis and electrochemical corrosion tests in boiler water have been carried out on cylindrical specimens, taken from the 13MnNiMoR steel welded joints at the direction across the weld. Metallographic structures, values of linear polarization resistance (Rp) and potentiodynamic polarization curves on sections normal to the axis of the specimens have been obtained. The results showed that the Rp values and potentiodynamic polarization curves of the weld joint were significantly varied with the microstructure among different zones. Results indicated that the overheating zone in HAZ shows the minimum value of Rp and the maximum value of corrosion current density (icorr), which make it the weakest part of the joint from a corrosion stand point.Copyright © 2015 by ASME