Studies On The Degree Of Sensitization Of Hyper-Duplex Stainless Steel 2707 At 900 Degrees C Using A Modified Dl-Epr Test

The effects of thermal aging of hyper-duplex stainless steel (HDSS) 2707 at 900 degrees C for various aging times up to 26 h on the localized, selective corrosion were investigated by electrochemical methods. The results demonstrate that the optimum test condition is 2 M H2SO4 + 1.25 M HCl + 0 0.001 M KSCN with the scan rate of 1.5 mV.s (-1) at 30 degrees C. The degree of sensitization (DOS) of HDSS 2707 initially increases rapidly, because of particle precipitation (sigma phase/Cr2N), and then decreases as a result of self-healing by back diffusion of Cr and Mo into the depleted areas, peaking at 10h.