GH3536合金电渣重熔铸锭微观组织演变行为  

Microstructure evolution behavior in electroslag remelting ingot of GH3536 alloy

作　　者：鄢宇灿 谷雨 贾雷 赵朋 李明宇 杨树峰[1] YAN Yucan;GU Yu;JIA Lei;ZHAO Peng;LI Mingyu;YANG Shufeng(School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing 100083,China;Department of Wrought Superalloy Product,Beijing GAONA Materials&Technology Co.,Ltd.,Beijing 100081,China;Collaborative Innovation Center of Steel Technology,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]北京科技大学冶金与生态工程学院,北京100083 [2]北京钢研高纳科技股份有限公司变形高温合金制品事业部,北京100081 [3]北京科技大学协同创新中心,北京100083

出　　处：《中国冶金》2024年第4期59-71,87,共14页China Metallurgy

基　　金：国家自然科学基金资助项目(52074092,52274330);钒钛资源综合利用国家重点实验室开放课题(2022P4FZG02A)。

摘　　要：由于高温合金铸锭由外向内凝固的原因,铸锭不同部位的冷却条件存在差异。当铸锭尺寸增大时,铸锭内部元素偏析情况加剧并产生粗大的析出相。为合理控制GH3536合金电渣重熔(ESR)铸锭内碳化物分布,为铸锭大型化发展提供理论基础,研究了铸锭不同部位元素偏析及碳化物的演变过程。结合实际工业生产情况,在实验室条件下采取定向凝固试验和MeltFlow-ESR有限元数值模拟等方法,研究了冷却速率和碳化物形貌及二次枝晶间距之间的关系。结果表明,凝固过程中Mo、W、Cr元素的偏析是碳化物形成的重要原因;随着冷却速率的提高,二次枝晶间距与碳化物面积分数均降低,较低的冷却速率使枝晶间距增大,易于形成M6C/M23C6复合型碳化物;其中一次枝晶间距λ1与冷却速率R_(c)呈λ_(1)=396.78G^(-0.5)Rc^(-0.25)的正比例关系(G为凝固界面前沿的温度梯度),二次枝晶间距λ_(2)与冷却速率呈λ_(2)=102.74Rc^(-0.36)的指数关系。对比工业铸锭生产情况与实际模拟结果发现,所得试验结果与数值模拟结果对应良好;进一步研究发现,熔化速率为230 kg/h时有利于获得均匀致密的凝固组织。Cooling conditions at different parts of the ingot is obviously different due to the solidification process of superalloy ingot with external preferential cooling.When the ingot size increases,the segregation of elements inside the ingot increases and generates coarse precipitated phases.To properly control the carbide distribution in ESR ingots of GH3536 alloy and provide a theoretical basis for the development of ingot size casting,elemental segregation and evolution of carbides at different parts of ingot were investigated.Combined with actual industrial production,the zonal melting liquid metal cooling experiments and finite element numerical simulation MeltFlow-ESR were adopted under laboratory conditions to study the relationship between cooling rate and carbide morphology and secondary dendrite spacing.The results indicate that the segregation of Mo,W and Cr elements during the solidification process is an important reason for carbide formation.With the increase of cooling rate,the secondary dendrite spacing and carbide phase area fraction both decrease,and the lower cooling rate increases the dendrite spacing,which is easy to form the composite carbide of M_(6)C/M_(23)C_(6).The primary dendrite spacing is λ_(1)=396.78G^(-0.5)Rc^(-0.25)positively proportional related to the cooling rate R_(c) and the secondary dendrite spacing isλ_(2)=102.74R_(c)^(-0.36)exponential related to the cooling rate.Comparison of industrial ingot casting and actual simulation results has revealed that the obtained numerical simulation results correspond well with the experimental results.It is further found that the melting rate of 230 kg/h is conducive to obtaining a uniform and dense solidification microstructure.

关 键 词：镍基高温合金 复合型碳化物 冷却速率 凝固偏析 有限元模拟 

分 类 号：TF142[冶金工程—冶金物理化学]