| 摘要: |
| 以不同热输入对轧制、铸态、铸后均匀化热处理3种2.8 mm厚Inconel-718薄板进行TIG焊试验.观察各接头母材与HAZ(焊接热影响区)组织,分析热输入对3种母材接头HAZ晶粒结构、大小的影响.发现随热输入增大,轧制母材焊接接头HAZ沉淀相大量溶解,等轴晶晶粒长大明显,速度为铸态或均匀化接头4.6倍.铸态或均匀化母材呈树枝晶,晶粒较大;HAZ偏析区扩散消失,奥氏体成分趋于均匀,树枝晶结构痕迹减弱;沉淀相残留于原枝晶间位置,在抑制HAZ晶粒长大的同时,保留部分树枝晶结构痕迹;铸态母材焊接接头HAZ沉淀相多于均匀化接头,更接近树枝晶结构. |
| 关键词: 镍基718合金 热输入 热影响区 晶粒 偏析 |
| DOI： |
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| Microstructure evolution of HAZ of TIG welded Ni-based 718 superalloy |
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YE Xin1,2, HUA Xueming1,2, WU Yixiong1,2
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1.Welding Engineering and Technical Institute, Shanghai Jiao Tong University, Shanghai 200240, China;2.Shanghai Key Laboratory of Materials Laser Processing and Modification, Shanghai Jiao Tong University, Shanghai 200240, China
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| Abstract: |
| The effect of different heat input on HAZ microstructure evolution in TIG welding was studied on 2.8 mm Inconel-718 sheets with wrought, as-cast and homogenized conditions. It was investigated that the microstructure and the grain size of all base metal and HAZ of welding joints with different heat input. With the heat input increased, precipitates dissolved in large quantities and equiaxial grains grew greatly in HAZ of the wrought joints. On the other hand, segregated structure was dispersed and a large number of residual precipitates was kept in HAZ interdendritic area of as-cast and homogenization joints, consequently, dendritic structure converted to equiaxed austenite gradually because of the widened width of intradendritic matrix and grain grew slightly because of precipitates' pinning effect on grain boundary migration. There were more precipitates in as-cast joints HAZ than homogenized sheet's joint result in more dendritic structure feature. |
| Key words: Inconel 718 heat input HAZ grain precipitates |
