51314-4070-Effects of Pitting and Inclusions on the Corrosion Fatigue of a CrMnN Stainless Steel

Available for download

Product Number: 51314-4070-SG

ISBN: 4070 2014 CP

Author: Wei Chen

Publication Date: 2014

Member Price: $0.00

Non Member Price: $20.00

Price: $20.00

Qty:

Pitting corrosion plays an important role in corrosion fatigue crack initiation and growth in austenitic stainless steels that are subject to an aqueous corrosive environment. It is well known that non-metallic inclusions such as sulfides can lead to preferential dissolution and pit formation. Consequently cleanliness of austenitic stainless steels as measured by levels of sulfides and other types of inclusions strongly influences the material's susceptibility to pitting corrosion and correspondingly its corrosion fatigue performance. However the synergistic effect of dynamic loading and pitting corrosion on corrosion fatigue is not well understood. In this study the electrochemical and corrosion fatigue properties of a high-strength CrMnN stainless steel are tested under a simulated drilling fluid environment. Pitting corrosion resistance of the material has been determined by means of cyclic potentiodynamic polarization tests in 18 wt.% NaCl solutions at 80°C. The corrosion fatigue strength was evaluated in a test bench under axial loading. Sulfide stringers on the gauge sections of the fatigue specimens dissolved after exposure to the corrosive environment leaving elongated microscopic porosities acting as surface defects. The detrimental role of inclusion dissolution is found to be dependent on the fatigue stress amplitude. A fracture mechanics-based approach is adopted to describe the interactions between pitting inclusion dissolution and corrosion fatigue performance.