Hydrogen Induced Stress Corrosion Of Duplex Stainless Steel Under Cathodic Protection in Artificial Seawater Of Different Hydrostatic Pressure

摘要

Duplex stainless steel has been the optimized material in subsea facilities because of the perfect chloride corrosion resistance. But duplex stainless steel used in deepwater will suffer from hydrogen induced stress corrosion (HISC) under cathodic protection, especially affected by hydrostatic pressure and subsea temperature. Hydrogen absorption on surface of duplex stainless steels under cathodic protection was discussed in this work. Under different pressure, hydrogen induced stress corrosion testing was carried by four-point bending test to investigate crack sensibility and morphology. Corrosion products were analyzed by X-Ray technology. Potentiodynamic polarizations were measured by electronic corrosion testing machine to research hydrogen evolution in different environment. Crack morphology and scale of deposit on surface of stainless steels were observed by scanning electron microscope. Hydrogen content was measured by inert gas fusion infrared absorptionmetry method. The results suggested that higher hydrostatic pressure accelerated hydrogen absorption on surface of duplex stainless steel, and hydrogen evolution reactions were different in deepwater of oxygen and free of oxygen.