Influence of normalizing temperature on pitting corrosion resistance of 2205/DH36 clad plate: a new mechanism for σ phase induced pitting corrosion

This work investigated the effect of normalization on σ phase precipitation and pitting corrosion resistance of 2205SS clad layer in 2205/DH36 clad plates. Results indicate normalization within 880 °C–920 °C leads to large amount of precipitation of σ phase, seriously deteriorating its pitting corrosion resistance. The pitting corrosion resistance of 2205SS is closely related to the proportion of σ phase. As the normalizing temperature increases from 880 °C to 940 °C, σ phase content gradually decreases with pitting corrosion resistance largely recovered. The significant deterioration in pitting corrosion resistance is attributed to the micro-galvanic corrosion effect induced by σ phase, but not Cr-depletion.