<p>To investigate the failure causes of 12Cr1MoVG steel tubes in the platen superheater of a Xinjiang power plant boiler, a systematic analysis of corrosion-induced failure was conducted through corrosion characterization and detection, combined with actual operational conditions. The results indicate that the chemical composition, microstructure, inclusions, and hardness of the failed tube met relevant standards, while its mechanical properties no longer complied with requirements. Abundant loose and porous corrosion products were observed on both the fire exposed side and opposite to fire exposed side of the failed tube. The outer oxide layer was primarily composed of Na₃Fe(SO₄)₃, Na₂SO₄, and Na₂CO₃, whereas the inner oxide layer mainly consisted of Fe₃O₄. The failure mechanism was attributed to sulfate-induced high-temperature corrosion, where pyrosulfates adhered to the 12Cr1MoVG surface reacted with the protective Fe₂O₃ film, generating complex sulfates. This process disrupted the compactness of the oxide film, ultimately leading to corrosion in the platen superheater tubes.</p>