ELECTROCHEMICAL BEHAVIOR OF LOW C - 13Cr WELD JOINTS BY USING SOLUTION FLOW TYPE MICRO-DROPLET CELL

摘要

Low Carbon-13%Cr martensitic stainless steels have been widely used for line pipe application because of their high strength and excellent corrosion resistance in corrosive conditions. Recently, both laboratory and field experiences related to cracking near fusion line of these steels weld joints in hot acid environments has been published. Electrochemical analysis of weld joints are expected to be effective to understanding crack mechanism. In this paper, electrochemical behavior of low C - 13%Cr weld joints was measured by using solution flow type micro-droplet cell. In this unique technique, a droplet with a diameter of hundreds of micrometers is used as an electrochemical cell and this technique enables local electrochemical measurements. Measurement of corrosion potentials and potentiodynamic polarization for HAZ portion of weld joints were focused.