Formation mechanism of basin-like depression defect in electric upsetting process of Ni80A superalloy  

Ni80A高温合金电镦成形中盆状凹陷的形成机理

作　　者：Guo-zheng QUAN Xue SHENG Kun YANG Yan-ze YU Wei XIONG 权国政;盛雪;杨焜;余炎泽;熊威(重庆大学材料科学与工程学院先进模具智能制造重庆市重点实验室,重庆400044;华中科技大学材料成形与模具技术国家重点实验室,武汉430074;南京杰品智能科技股份有限公司,南京210000;清华大学核能与新能源技术研究所先进核能技术协同创新中心先进反应堆工程与安全教育部重点实验室,北京100084)

机构地区：[1]Chongqing Key Laboratory of Advanced Mold Intelligent Manufacturing,College of Materials Science and Engineering,Chongqing University,Chongqing 400044,China [2]State Key Laboratory of Materials Processing and Die&Mould Technology,Huazhong University of Science and Technology,Wuhan 430074,China [3]Nanjing Jiepin Intelligent Technology Co.,Ltd.,Nanjing 210000,China [4]Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education,Collaborative Innovation Center of Advanced Nuclear Energy Technology,Institute of Nuclear and New Energy Technology,Tsinghua University,Beijing 100084,China

出　　处：《Transactions of Nonferrous Metals Society of China》2022年第10期3276-3290,共15页中国有色金属学报（英文版）

基　　金：support from the National Natural Science Foundation of China(No.52175287);Open Fund of State Key Laboratory of Materials Processing and Die&Mould Technology,China(No.P2020-001).

摘　　要：A kind of surface instability,basin-like depression defect companied by mixed grain structure at the bottom of large-scale valve during electric upsetting process,would significantly influence the microstructures and mechanical properties of components.In order to analyze the forming process of the basin-like depression defect,a finite element model for the electric upsetting process of Ni80A superalloy was developed using multi-field and multi-scale coupling analysis method.Subsequently,a series of parameters loading path schemes for force and current were designed by varying the initial value,peak value and value level,and their effects on basin-like depression and mixed grain structure were simulated and uncovered.It is concluded that the changes of heating speed and pressurization speed result in the different flow velocities between the inner and outer layers of billet,thus exerting the basin-like depression.Simulation results also indicate that these defects can be optimized through the parameter coordination between force and current.Finally,the validity and reliability of the finite element model were verified by physical experiments in electric upsetting process.大规格气阀在电镦成形过程中经常存在盆状凹陷缺陷,并伴随混晶组织,缺陷对工件的显微组织和力学性能影响较大。为了分析盆状凹陷的形成过程,建立Ni80A高温合金多场、多尺度耦合的电镦有限元模型。随后,通过改变力、电流参数的初始值、峰值和水平,设计一系列力和电流参数加载路径方案,模拟并揭示参数对盆状凹陷和混晶结构的影响。结果表明,电镦成形过程中加热速度和加压速度的变化导致坯料内外层的流速不同,从而产生盆状凹陷。通过力和电流参数的协调,可以对这些缺陷进行优化。最后,通过电镦工艺的物理实验验证有限元模型的有效性和可靠性。

关 键 词：electric upsetting process DEFECT Ni80A superalloy microstructure evolution mixed grain structure 

分 类 号：TG316.11[金属学及工艺—金属压力加工]