Purification behaviour of GH4169 scraps under argon atmosphere during vacuum induction melting

Abstract

The purification behaviour of GH4169 scraps under argon atmosphere was systematically investigated. The experiments were performed by vacuum induction melting technology using Y₂O₃ crucible. The denitrogenation and carbon-deoxidation behaviours at different temperatures under argon atmosphere were clarified by thermodynamics and kinetics analysis. The results indicated that argon atmosphere played an important role in the denitrogenation and deoxidation behaviours. The oxygen and nitrogen contents of the samples decreased with increaing vacuum degree. Under the same argon atmosphere, nitrogen and oxygen level presented a distinct trend with temperature. Nitrogen content did not change significantly with temperature increasing while oxygen content had a minimum value at 1873 K. In the absence of argon atmosphere, the nitrogen and oxygen contents in the alloy could be reduced from 72×10⁻⁶ to 7×10⁻⁶ and 28×10⁻⁶ to 8×10⁻⁶, respectively.

Keywords:

• Purification
• Vacuum induction melting
• Denitrogenation
• Deoxidation
• Thermodynamic

Acknowledgements

The authors would like to acknowledge financial support for this research from the State Science and Technology Support Program (2013BAB11B04).