Reduction of Life Time Expectation of Standard Duplex Stainless Steel Exposed to Hydrogen under Corrosion Fatigue Conditions

Abstract

In geothermal environment corrosion fatigue lowers the lifetime expectancy of high alloyed steels. Therefore, cathodic protection enhances corrosion resistance although hydrogen is produced during the cathodic reactions under applied potential. Corrosion fatigue of standard duplex stainless steel X2CrNiMoN22-5-3, 1.4462 specimen loaded with hydrogen was investigated in a specifically designed corrosion chamber surrounded by the Northern German Basin electrolyte at 369 K. The reactions of the microstructure associated with hydrogen incorporation lowers the number of cycles to failure of specimen significantly at various stress amplitudes, for example at σa = 275 MPa and USHE = -36 mV by 80%. Hydrogen enhances crack propagation and early failure due to the degradation of the mechanical properties of the ferritic phase.