Abstract Buttering layer (BL) was used to weld two ultra-supercritical turbine rotor steels. Low-cycle fatigue behavior of different regions in the dissimilar metal welded joint (DMWJ) was compared and evaluated at 280 °C. Microstructure, fracture and weak link were observed by OM, SEM, EDS and TEM. BL had lower fatigue life than weld metal (WM) and base metals (BMs). Weld zone showed cyclic softening characteristic. Microstructures evolved into cell structures after LCF tests. Fatigue crack in weld zone propagated mainly through coarse carbides. The interface near BL was the weakest link of the DMWJ due to ferrite layer and strength mismatch.

中文翻译：

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280℃超超临界涡轮转子异种钢与焊缝LCF行为对比评价

摘要 涂油层（BL）用于焊接两种超超临界涡轮转子钢。对异种金属焊接接头 (DMWJ) 中不同区域的低周疲劳行为进行了比较和评估，在 280 °C 下进行了评估。通过OM、SEM、EDS和TEM观察显微组织、断裂和薄弱环节。BL 的疲劳寿命低于焊接金属 (WM) 和母材 (BM)。焊缝区呈循环软化特征。经过 LCF 测试后，微观结构演变成细胞结构。焊接区疲劳裂纹主要通过粗大的碳化物传播。由于铁氧体层和强度不匹配，BL 附近的界面是 DMWJ 的最薄弱环节。