Hastelloy C-2000 and C-276 are widely used in Flue Gas Desulphurization (FGD) system and Chemical Processing Industries (CPI). Current work is focused on weld microstructure, and mechanical properties (structure-property relationship) of the dissimilar combination of alloy C-2000 and C-276. Multi-pass Pulsed Current Gas Tungsten Arc (PCGTA) welding was adopted for joining the dissimilar alloys using the filler ERNiCrMo-17. Microstructural characteristics of the weld joint were assessed by Optical and Scanning Electron Microscope (SEM). Weld interface microstructure examination revealed the presence of grain coarsening near the Heat Affecting Zone (HAZ) of the alloy C-276 side. SEM analysis shows the absence of secondary Topologically Closed Packed (TCP) phases in the Inter-Dendritic (ID) regions of the dissimilar weld. Micro-segregation of alloying elements in the weldment was assessed by Energy-Dispersive X-ray Spectroscopy (EDS). X-Ray Diffraction (XRD) analysis had been carried out to identify the phase constitution and average grain size. Strength, toughness, and hardness of the dissimilar weld were evaluated with the support of the tensile test, Charpy impact test, and Vicker’s hardness test. Tensile study showed that all the tensile fracture occurred at the base metal side of alloy C-276. The average toughness of the dissimilar alloy joint was noted about 84 J. Hardness test results indicated that fusion zone (FZ) hardness value was 6.19% and 2.27% superior to the candidates’ material (C-276 and C-2000) employed in this study. The refined grain structure and absence of microsegregation resulted in the highest hardness in the dissimilar weld FZ. Results revealed the substantiated use of PCGTA welding for the effective joining of dissimilar alloys of C-2000 and C-276 through the evaluation of metallurgical and mechanical characteristics.

哈氏合金C-2000和C-276被广泛用于烟气脱硫（FGD）系统和化学加工工业（CPI）。当前的工作集中在合金C-2000和C-276的不同组合的焊缝微观结构和力学性能（结构-性能关系）上。采用多通道脉冲电流钨极氩弧焊（PCGTA）来焊接使用填料ERNiCrMo-17的异种合金。通过光学和扫描电子显微镜（SEM）评估了焊接接头的微观结构特征。焊接界面的显微组织检查表明，在合金C-276侧面的热影响区（HAZ）附近存在晶粒粗化。SEM分析表明，在异种焊缝的枝晶间（ID）区域中没有次要的拓扑密堆积（TCP）相。焊缝中合金元素的微偏析通过能量色散X射线光谱（EDS）进行评估。已经进行了X射线衍射（XRD）分析以鉴定相组成和平均晶粒尺寸。在拉伸试验，夏比冲击试验和维氏硬度试验的支持下，评估了异种焊缝的强度，韧性和硬度。拉伸研究表明，所有的拉伸断裂都发生在合金C-276的贱金属侧。异种合金接头的平均韧性约为84J。硬度测试结果表明，熔合区（FZ）的硬度值比候选合金（C-276和C-2000）高6.19％和2.27％。学习。细化的晶粒结构和不存在微偏析导致在异种焊缝FZ中具有最高的硬度。