热顶设计对镍基高温合金铸锭收缩孔隙的影响  

Effect of hot top design on shrinkage porosity of nickel-based superalloy ingots

作　　者：王建武 徐志强 杨树峰 WANG Jian-wu;XU Zhi-qiang;YANG Shu-feng(School of Advanced Engineering,University of Science and Technology Beijing,Beijing 100083,China;State Key Laboratory of Advanced Metallurgy,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]北京科技大学高等工程师学院,北京100083 [2]北京科技大学钢铁冶金新技术国家重点实验室,北京100083

出　　处：《中国冶金》2022年第4期63-69,76,共8页China Metallurgy

基　　金：河北省省级科技计划资助项目(20311007D)。

摘　　要：为减轻缩孔缺陷以降低铸锭头部切除率进而提高铸锭成材率,通过数值模拟研究了热顶高度和热顶预热温度对铸锭收缩孔隙率的影响。对φ350 mm×3200 mm的高温合金铸锭进行纵向剖切来验证模拟精确性,并结合试验测试和反算法确认了合理的铸锭与锭模界面换热系数,阐明了热顶最优设计方案。试验结果表明,不采用加热冒口时,铸锭缩孔达到1400 mm并在铸锭中下部出现严重的疏松缺陷。通过有限元数值模拟,验证了镍基高温合金铸锭中心疏松形成条件。过高的热顶高度和预热温度会加剧中心疏松,相反会降低铸锭缩孔高度。因此,为全面控制这两个缺陷,设定φ350 mm高温合金铸锭最佳热顶高度和预热温度为600 mm和900℃,这一标准已成功用于优化φ350 mm高温合金铸锭生产。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 φ350 mm×3200 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 1400 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 φ350 mm superalloy ingots are established and this criterion has been successfully used to optimise the production of φ350 mm superalloy ingots.

关 键 词：PROCAST 铸造 缺陷模拟 缩松缩孔 冒口 

分 类 号：TG245[金属学及工艺—铸造]