| C19400 copper alloys due to the low production cost and easy to develop,become the do sage is one of the biggest lead frame materials,the past is lead frame with the method of coini ng,in recent years,the integrated circuit direction is toward higher density,distance between l ead frame of the pin from 0.12 mm to 0.05 mm,processing method also from coining into the etching,The requirements of strip residual stress are also more stringent.The residual stress o f the strip produced by the previous process is large,and the frame deformation is caused by t he large residual stress inside the strip when the downstream manufacturer makes the lead fra me.Therefore,it is an important problem to improve the production process of the strip and c ontrol the residual stress.In this paper,C19400 copper alloy was used as raw material,and its properties and microstructure were tested after cold rolling process.The residual stresses of al loys in different states were measured and calculated.ABAQUS finite element software was u sed to simulate the influence of some cold rolling parameters on the residual stress of strip dur ing the cold rolling process.The specific research work is as follows:(1)After aging at 400?,450?,500?,550?,600? and 650? for 0.5h,1h,2h,3h,4h and 6h respectively,the properties and microstructure of each alloy after aging were tested an d observed.The aging peaks of conductivity and hardness did not appear at the same time.Th erefore,the first aging process was selected as 500?+2h.After aging,the hardness value of t he alloy was 138.8HV and the conductivity was 51.7%IACS.After the first cold rolling and a ging at 500?+2h,the alloy continued to deform 66% after cold rolling and aging at 450? fo r 0.5h,1h,2h,3h,4h and 6h,respectively.The properties and microstructure of each alloy afte r aging were tested and observed.Considering the conductivity and hardness,the second agin g process was selected as 450?+4h.After aging,the alloy with hardness of 149 HV and cond uctivity of 60.2%IACS was obtained.(2)For the second time after 450?+4h aging alloy continued to 60% of the cold rolling deformation and annealing at 400? for 4 hours,the main purpose is to precipitate residual sol ute atoms and eliminate work hardening,to prepare for the final deformation of the alloy,the alloy after annealing has softened and recrystallization.The alloy was subjected to 36.5% fina l cold rolling deformation and stress relief annealing.The properties of the alloy were tested a nd the microstructure was observed.The alloy with conductivity of 61.6%IACS,hardness of142.3HV and tensile strength of 461 MPa was obtained.(3)The residual stress of the alloy under different pressure and different states was meas ured and calculated.The surface of the alloy with 20% pressure and 40% pressure is compress ive stress,and the surface of the alloy with 60% pressure changes from compressive stress to t ensile stress.Finally,the residual stress of the two sides of the alloy without stress-relieving a nnealing is 62.35 mpa and 22.87 mpa respectively,and the residual stress of the two sides of th e alloy after stress-relieving annealing is 3.66 mpa and 0.21 mpa respectively,which is greatly reduced compared with that before the process improvement.(4)respectively with ABAQUS software to simulate the friction factor in the process of r olling,plate width and rolling speed for C19400 copper alloy plate with the influence of resid ual stress,found that the friction coefficient and the width of medium plate rolling process wit h basic have no effect on residual stress,roll speed impact plate with the size of the residual st ress and affect the distribution of residual stress. |
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