Improvement of Microstructure and Mechanical Behavior of Gas Tungsten Arc Weldments of Alloy C-276 by Current Pulsing
Improvement of Microstructure and Mechanical Behavior of Gas Tungsten Arc Weldments of Alloy C-276 by Current Pulsing
复制标题
DOI：
10.1007/s40195-014-0186-4
复制
发表时间：
2015-02-01
影响因子：
3.5
通讯作者：
Reddy, G. Madhusudhan
中科院分区：
文献类型：
--
作者：
Manikandan, M.;Arivazhagan, N.;Reddy, G. Madhusudhan
已知高温合金C-276在通过气体钨极电弧法进行熔焊期间易于产生热裂纹。熔合区冷却过程中发生的微观偏析，以及随后出现的拓扑紧密堆积相P和μ相，是造成所观察到的热裂纹的原因。本文研究了采用脉冲电流抑制焊件微观偏析的可能性。采用ERNiCrMo-4焊丝，分别采用连续钨极氩弧焊和脉冲钨极氩弧焊焊接。焊接接头的显微组织，显微偏析和力学性能进行了研究。采用光学显微镜和扫描电子显微镜研究了其微观结构。能量色散X射线光谱进行评估的程度的显微偏析。进行拉伸测试以确定强度和延展性。结果表明，脉冲电流焊接接头焊缝较窄，几乎没有热影响区，熔合区显微组织细化，显微偏析减少，力学性能上级组合。
Superalloy C-276 is known to be prone to hot cracking during fusion welding by Gas Tungsten Arc method. Microsegregation occurring during cooling of fusion zone with consequent appearance of topologically close-packed phases P and mu has been held responsible for the observed hot cracking. The present work investigated the possibility of suppressing the microsegregation in weldments by resorting to current pulse. Weldments were made by continuous current gas tungsten arc welding and pulsed current gas tungsten arc welding using ERNiCrMo-4 filler wire. The weld joints were studied with respect to microstructure, microsegregation, and mechanical properties. Optical microscopy and scanning electron microscopy were employed to study the microstructure. Energy-Dispersive X-ray Spectroscopy was carried out to evaluate the extent of microsegregation. Tensile testing was carried out to determine the strength and ductility. The results show that the joints fabricated with pulsed current gave rise to narrower welds with practically no heat affected zone, a refined microstructure in the fusion zone, reduced microsegregation, and superior combination of mechanical properties.