Abstract:  In this paper ， the microstructure of Inconel 783 alloy 508 mm ingot produced by VIM+VAR process in Daye Special Steel was analyzed by means of optical microscope， SEM， XRD and DSC. The results show that the ingot crown can be divided into two equiaxed crystal zones and two columnar crystal zones， and the shrinkage cavity depth of the ingot crown is about 70 mm. Within 50-100 μm thick area of the ingot surface， there is a large number of phase β precipitation. The average dendrite spacing in the center of the VAR ingot is about 131 μm， and there are a lot of white Nb-rich inter-dendritic phases in the center of the ingot. The solution temperature of the inter-dendritic phase is 1 189.6-1 209.7 ℃. The matrix of the VAR ingots is a typical face-centered cubic structure with a lattice constant of 0.356 9 nm. The melting temperature of the VAR ingots is 1 356.8-1 399.6 ℃.

Key words: Inconel 783 Alloy, VAR Ingot, Inter-dendritic Phase, Melting Point

摘要： 以大冶特钢VIM+VAR工艺生产的Inconel 783合金508 mm自耗锭为研究对象，采用光学显微镜、SEM、XRD、DSC等手段分析自耗锭的组织情况。结果表明：自耗锭锭冠可分为两个等轴晶区和两个柱状晶区，锭冠的缩孔深度大约为70 mm；自耗锭表层50～100 μm厚度区域内有大量的β相析出，自耗锭中心部位的平均枝晶间距大约为131 μm，中心部位有大量的白色富Nb的枝晶间相，枝晶间相的固溶温度点在1 189.6～1 209.7 ℃；自耗锭基体为典型的面心立方结构，晶格常数为0.356 9 nm，自耗锭的熔点温度在1 356.8～1 399.6 ℃。

关键词: Inconel 783合金, 自耗锭, 枝晶间相, 熔点