Effect of melt superheating time on solidification microstructure of superalloy K4169

The melt superheating treatment was conducted on K4169 Ni-based cast superalloy at 1680°C. The influence between loss of element, macroscopic grain size, solidification microstructure, the segregation degree of alloy elements and different melt superheating time at the same melt superheating temperature is explored. The results show that alloy composition of melt superheat treatment is still in the permitted range within 10 min Cr has been seriously damaged when melt superheating time has been kept for 15 min at 1680°C. Macroscopic grain size is increased, secondary dendrite arm spacing is refined, and the segregation degree of alloy elements is decreased when the melt superheating time increases from 5 min to 10 min. When melt superheating treatment time is prolonged to 15 min, the dendrite arms become coarse and the segregation degree of alloy elements is increased. Macroscopic grain size and secondary dendrite arm spacing refining size can reach M-7, 34.95 μm respectively and the segregation degree of alloy elements is the lightest when melt superheating temperature time has been kept for 10 min.