Wednesday, March 25, 2009: 3:25 PM
C304 (Georgia World Congress Center)
Intergranular stress corrosion cracking (IGSCC) of weldable martensitic stainless steels
(WMSS) has been a major concern in the oil and gas industry. It occurs under sweet and
mildly sour wet service conditions and in the presence of hot chlorides. The cracking
phenomenon is assumed to be due to the formation of chromium carbides on former austenite
grain boundaries in the heat affected zone of the weld. The chromium depletion in the
surrounding matrix results in susceptibility to IGSCC. A combined approach using localized
electrochemical measurements and scanning probe microscopy (SPM) techniques was
utilized to locate sensitized zones in rich grade WMSS. The electrochemical measurements
were performed using a custom built micro cell allowing measurements on small spot sizes.
The resulting etched working electrode surfaces were then examined by atomic force
microscopy (AFM). The electrochemical results corresponded well with local metal
dissolution and etching imprints obtained using AFM respectively. Performing local
electrochemical tests in combination with SPM investigation proved very valuable. The
imprint on the working electrode surface left after electrochemical analysis revealed
sensitized zones in both actual welded samples and simulated welded samples.
See more of: Advances in Materials for Oil and Gas Production Session 1- STG 32
See more of: Technical Symposium
See more of: Technical Symposium