Details

Autor(en) / Beteiligte

• Zhang Xu
• Wan Jinchu
• Zhu liang
• Zhou Hui
• Yang Zonghui

Titel

Influence of Nb on the hot corrosion behaviors of a Fe-Cr-Ni heat-resistant steel weld metal in the Na2SO4-NaCl molten salt at 700

Ist Teil von

• Metals and Materials International, 2023, 29(12), , pp.3645-3654

Ort / Verlag

대한금속·재료학회

Erscheinungsjahr

2023

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• A multiple gas tungsten arc welding was performed on the fabrication of the Fe–Cr–Ni-based weld metal. Microstructuresand hot corrosion behaviors of the non-equilibrium weld metals with different Nb contents in 75 wt%Na2SO4–25 wt%NaClmolten salt at 700 °C have been investigated. A bilayer oxide film composed of an inner Cr2O3layer and an outer Fe2O3layer formed on the surface of the weld metals. The mass gain rate and the thickness of the surface oxide film were enlargedwith Nb addition, which could be attributed to the rapid inward diffusion of O through the cracks resulting from the Nboxide. Oxidation and sulfidation occur in the matrix, resulting in a large internal oxidation zone (IOZ) in the weld metal. Nb seemly promoted the sulfidation reaction due to a short-circuit diffusion of S through the interface of the Nb(C, N)and matrix and made the internal corrosion products to be distributed along the interdendritic zone of the weld metal. Anapparent Cr-dealloyed layer appears in the IOZ of the weld metal. Dealloying was the detrimental form of hot corrosion ofFe–Cr–Ni-based weld metal exposed to molten salts containing chloride salts. Alloying with 0.8 wt% of Nb further acceleratedthe dealloying and resulted in a profound attack. KCI Citation Count: 0