Cracking in fusion zone and heat affected zone of electron beam welded Inconel-713LC gas turbine blades
Cracking in fusion zone and heat affected zone of electron beam welded Inconel-713LC gas turbine blades
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DOI：
10.1016/j.msea.2015.06.087
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发表时间：
2015-08-26
期刊：
影响因子：
6.4
通讯作者：
Firoozrai, A.
中科院分区：
文献类型：
--
作者：
Chamanfar, A.;Jahazi, M.;Firoozrai, A.
Inconel-713LC低压燃气轮机叶片护罩的电子束焊接容易产生熔合区(FZ)和热影响区(HAZ)裂纹，导致叶片制造过程中废品率较高。在这项研究中，为了绘制详细的裂缝图并了解裂缝的根本原因，对其进行了全面的微观组织和数值分析。扫描电子显微镜(SEM)-能谱分析的元素图谱显示，合金元素在FZ和HAZ的裂纹区偏聚。也就是说，FZ和HAZ的开裂机制之一是偏析导致熔化，随后由于电子束焊接过程中产生的热应力和机械拉应力而开裂。FZ中的裂纹也是由于凝固焊缝金属强度低以及凝固收缩造成的。此外，热影响区中的伽马溶解和再析出导致塑性降低和产生收缩应力是热影响区开裂的另一种机制。该数值模型能够预测裂纹的位置以及相对于熔接痕的裂纹方向。(C)2015爱思唯尔B.V.保留所有权利。
Electron beam welding (EBW) of shrouds in Inconel-713LC low pressure gas turbine blades was associated with cracking in fusion zone (FZ) and heat affected zone (HAZ) leading to a high scrap rate in manufacturing of gas turbine blades. In this study, in order to develop a detailed map of cracks and understand the root cause of cracking, a comprehensive microstructural and numerical analysis was performed. The elemental mapping in scanning electron microscope (SEM)-energy dispersive spectral analysis revealed segregation of alloying elements in the cracked area of FZ and HAZ. In other words, one of the cracking mechanisms in FZ and HAZ was found to be segregation induced liquation and subsequent cracking due to thermal and mechanical tensile stresses generated during EBW. Cracking in FZ also occurred because of low strength of the solidifying weld metal as well as solidification contraction. As well, gamma' dissolution and reprecipitation in HAZ leading to decreased ductility and generation of contraction stresses was another mechanism for cracking in HAZ. The numerical model was capable to predict the cracking location as well as cracking orientation with respect to the weld line. (C) 2015 Elsevier B.V. All rights reserved.