Effect of Na-based flux on melt quality assessment of 46,000 alloys

Abstract

The influence of Na-Based flux on the melt quality assessment was studied using Density index (DI), bifilm index (BI) and tensile test. The melt was prepared with scrap and ingot with and/or without the addition of Na-based flux. The results show that the addition of Na-based flux decreases the accuracy of the correlation between BI/DI and the hydrogen content due to the increased shrinkage pores. The addition of flux promotes the formation of shrinkage pores by either altering the eutectic solidification behavior or generating more and bigger oxide films which leads to insufficient feeding. Moreover, the addition of flux improves the ductility of specimens by modifying the eutectic phase rather than improving the melt quality.

Keywords

• Melt quality
• Bifilm index
• Reduced pressure test
• Shrinkage
• Flux
• Tensile test