Fundamental Research On Hot Rolling Process Of Cu-Ni-Co-Si Alloy Plates

Cu-Ni-Si alloy,as a representative material of high strength and high elasticity alloy,has good physical properties and is the key material for lead frame of electronic integrated circuits.Cu-Ni-Co-Si alloy has better strength and conductivity,which is suitable for the preparation of large-scale integrated circuit lead frame strip.In order to meet the requirements of ultra-fine crystallization and dispersion of inclusions in wide-width ultra-thin Cu-Ni-Co-Si alloy strip,the thermal deformation behavior and microstructure evolution of as-cast Cu-Ni-Co-Si alloy were studied by thermodynamic simulation experiments.The constitutive relationship and thermal working diagram of as-cast microstructure of the alloy were analyzed and established.The influence of hot rolling process parameters on the distribution of macroscopic thermodynamic parameters and the deformation characteristics of inclusions during single pass and multiple pass forming of slabs was studied by numerical simulation method,in order to provide a basis and reference for the formulation of hot rolling process of Cu-Ni-Co-Si alloy casting slab.The high temperature compression deformation test of as-cast Cu-Ni-Co-Si alloy was carried out by thermodynamic simulation tester.The deformation temperature ranges from 700 ℃ to 900℃,and the strain rate ranges from 0.1s-1 to 5 s-1.The true stress-true strain curves of the as-cast microstructure of the alloy under different process conditions were obtained,and the relationship among deformation temperature,strain rate and flow stress was analyzed.The constitutive model of thermal deformation of as-cast microstructure of Cu-Ni-Co-Si alloy was established.The optimum thermal deformation range is840 ～ 900 ℃ /s-1,based on the thermal working diagram of the as-cast microstructure at 0.6 strain.The geometric model of Cu-Ni-Co-Si alloy single pass rolling was established based on Deform-3D numerical simulation software.The simulation results show that the equivalent stress value increases with the decrease of hot rolling temperature,rolling speed and rolling amount.The temperature field along the slab surface presents a ladder pattern,the rolling plate temperature from the substrate surface to the middle part presents an increasing trend,the plate temperature will continue to rise with the reduction amount and rolling speed increase,through comprehensive analysis to optimize the range of plate process parameters.The geometric model of multi-pass hot rolling of Cu-Ni-Co-Si alloy and plastic inclusions was established by Solidworks.Through Deform-3D numerical simulation of multi-pass hot rolling sheet,the plastic inclusions gradually change from elliptic to flat strip,and the optimal process parameters of each pass hot rolling sheet are 23%,24.3%,21.4%,21.9%,21.3%,21.4%,23%,25.9%,20%.The plastic inclusion size decreases and the total deformation of the inclusion decreases in the rolling process by analyzing the changes of the plastic inclusion with different sizes in the seventh pass.At the same time,the ultimate crushing size of the brittle inclusions is 3 m under the technological parameters in this paper.