Interfacial microstructure evolution of 12Cr1MoV/TP347H dissimilar steel welded joints during aging

• 作者: Yuan Li Yan-ping Zeng Zhi-chun Wang
• 来源期刊: 矿物冶金与材料学报
• 年，卷（期）: 2021,（9）
• 页码范围: 1497-1505
• 页数: 9页
• 语种: 英文

摘要

The interfacial microstructure evolution of 12Cr1MoV/TP347H dissimilar steel welded joints with a nickel-based filler metal during aging was studied in detail to elucidate the mechanism of premature failures of this kind of joints. The results showed that not only a band of granular Cr23C6 carbides were formed along the fusion boundary in the ferritic steel during aging, but also a large number of granular or plate-like Cr23C6 carbides, which have a cube–cube orientation relationship with the matrix, were also precipitated on the weld metal side of the fu-sion boundary, making this zone be etched more easily than the other zone and become a dark etched band. Stacking faults were found in some Cr23C6 carbides. In the as-welded state, deformation twins were observed in the weld metal with a fully austenitic structure. The peak micro-hardness was shifted from the ferritic steel side to the weld metal side of the fusion boundary after aging and the peak value increased signific-antly. Based on the experimental results, a mechanism of premature failures of the joints was proposed.