Effect of hot top design on shrinkage porosity of nickel-based superalloy ingots
WANG Jian-wu1, XU Zhi-qiang2, YANG Shu-feng2
1. School of Advanced Engineering, University of Science and Technology Beijing, Beijing 100083, China; 2. State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, China
Abstract：In order to reduce the ingot shrinkage defects, reduce the ingot head removal rate and improve the ingot yield, the effect of hot top height and hot top preheating temperature on the ingot shrinkage porosity was investigated by numerical simulation. A longitudinal section of a ø350 mm×3 200 mm high-temperature alloy ingot was performed to verify the accuracy of the simulation, and a reasonable heat transfer coefficient at the interface between ingot and mould was determined by combining experimental tests and an inverse algorithm. The optimal design scheme of hot top was expounded. The experimental results show that without a heated riser, the ingot shrinkage reaches 1 400 mm and serious loosening defects appear in the lower and middle part of the ingot. The conditions for the formation of center sparsity in nickel-based superalloy ingots were verified by finite element numerical simulations. The hot top height and preheating temperature too high will aggravate the central sparring and on the contrary will reduce the ingot shrinkage height. Therefore, in order to fully control these two defects, the optimum hot top height and preheating temperature of 600 mm and 900 ℃ for ø350 mm superalloy ingots are established and this criterion has been successfully used to optimise the production of ø350 mm superalloy ingots.
王建武, 徐志强, 杨树峰. 热顶设计对镍基高温合金铸锭收缩孔隙的影响[J]. 中国冶金, 2022, 32(4): 63-69.
WANG Jian-wu, XU Zhi-qiang, YANG Shu-feng. Effect of hot top design on shrinkage porosity of nickel-based superalloy ingots[J]. China Metallurgy, 2022, 32(4): 63-69.
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2022, Vol. 32 
