Electrochemical Noise Analysis of 13 mass% Cr Stainless Steel HAZ by Solution Flow Type Micro-droplet Cell-Effect of Solution Concentration-

Abstract

Low Carbon- 13 mass% Cr martensitic stainless steels have been widely used for line pipe application because of their high strength and excellent corrosion resistance in corrosive conditions. Newly developed solution flow type micro-droplet cell was applied to investigate electrochemical behavior of heat affected zone (HAZ) of 13 mass% Cr stainless steel. This technique makes it possible to measure electrochemical behavior of very narrow area of HAZ. Effects of solution pH and stress on corrosion potentials, and current at constant potential for HAZ portion of welded joints were focused. The corrosion potentials at HAZ and base metal show almost same tendency, however, current change shows clear difference of corrosion resistance at HAZ and base metal.