This work aims to obtain the degree of sensitization (DOS) of HAZ from a SMSS (UNS S41426) welded joint before and after post weld heat treatments at 650°C for 5 and 15 minutes using a minicell with less than 1 mm in diameter and double loop electrochemical potentiokinetic reactivation (DL-EPR) test. The solution used was 0.25 mol L-1 H2SO4 and 0.01 mol L-1 KSCN. The DOS value in the HAZ near the weld cap (29%) was influenced by the presence of delta ferrite confirmed in SEM images, while the DOS value in the HAZ of the root region (45%) was also affected by the Cr-rich carbide precipitation due to the thermal cycle of the multipass welding process. The corrosion occurs next to delta ferrite, this was confirmed by AFM images. The PWHT at 650°C increased the DOS value in every spot of the HAZ by a factor of 1.5.

Subject
Scanning electron microscopy, Precipitation (solids), Filler metals, Atomic force microscopy, Welding, Joints, Base metals, Welded joints, Steel, Sensitization, Corrosion resistance, Stainless steel, Ferrite
Keywords:
welding, corrosion, electrochemistry
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2023
Association for Materials Protection and Performance (AMPP)
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