Study The Direct Rolling Of Nickel Strip Foil By Electrolytic Nickel Plate

With the development of the market economy,high-value-added products led by various high-technology are coming out all the time,and nickel products such as nickel plates and foils will be required higher quality and larger quantities.As a new approach that electrodeposited nickel is directly rolled into nickel foil.At present,the production and application range of rolling directly into nickel foil is still in germination and development stage,but it has fully demonstrated the advantages of short-process rolled nickel foil over traditional production of nickel foil.The traditional manufacturing process for nickel foil is as follows: firstly,the electrodeposited nickel plate is cast into a nickel ingot,and then the hot rolling process is used to perform preliminary rolling,and then multiple cold rollings are employed until the production requirements are met.In this article,the electrodeposited nickel plate produced by a company,used as a research object,its organization and performance were investigated.During the direct rolling process,the rolling property is studied by characterization of multiple analytical methods.Studies have shown that:The electrodeposited micro-nano nickel blanks produced by this process are divided into three layers along the thickness of the plate: the starting plate is in the middle layer and the thickness is 1 mm,the deposited layers are on both sides.and the combination of sedimentary layer and initial plate is uniform and dense.The grain size distribution of the electrodeposited nickel is relatively large,and the grains distributed in the range of 0.5 ?m to 1.5 ?m is about 75% of the total number of crystal grains.there are a large number of growth twins,and the width is 200 to 400 nm.Nano-nickel prepared by electrodeposition is still a face-centered cubic structure,which is selected for optimal growth in three crystal faces:(111),(200)and(220).The tensile strength of the electrodeposited micro-nano nickel is between 385 MPa and 461 MPa,which confirms to the strength index stipulated by the national standard for electrolytic nickel.The electrodeposited nickel fracture of tensile specimen has a distinct plastic dimple fracture morphology.The starting sheet organization is significantly more dense and uniform than the deposited layer and the fracture dimple is elongated.The surface is smooth and has a better toughness.This indicates that The starting sheet can enhance the strength of nickel electrolysis.When the electrodeposited nickel is subjected to multi-pass rolling,and the deformation degree reached 90%,the grain size is significantly minished and the grain size distributed between 200 nm and 600 nm is about 52%.With the increase of the deformation degree,the hardness value of the material gradually increases,and obvious work hardening was occured during rolling.The randomly oriented grains gradually appeared preferential distribution during the rolling process.With the augment of the rolling deformation degree,this preferential phenomenon became more and more obvious.When the rolling degree reached 98%,Tc(220)equals 76.4%.A deformation texture appeared on(220)surface.Up to 98% of the stack for sample can be fractured,indicating good plasticity and toughness.After annealing,the rolling samples microhardness of the electrodeposited nickel in various stages were decreased,and with the enhance of rolling degree,the difference is greater.When the rolling deformation degree is 20%,the microhardness does not change much before and after rolling.When the rolling deformation is 90%,the maximum value is reached,and the difference between the two is 87 HV,which completely softens the material.The strength of the unheated specimen after per pass rolling of electrodeposited nickel increased from an average of 503 MPa to 873 MPa as the augment of rolling degree;The elongation rate decreased from 6.6% to 1.1% with the increase of the rolling deformation.After each pass of heat treatment,the strength after rolling is lower than that before rolling,and the elongation is high.Among them,the strength and elongation before and after heat treatment of 20% and 50% rolling degree are not much different,and the difference between strength and elongation before and after heat treatment of 70% and 90% rolling degree is huge.In particular,the strength after heat treatment at a rolling degree of 90% was reduced by 405 MPa and the elongation was increased by 17.7% compared with that before heat treatment.The fracture morphology of all specimens is a typical dimple structure,which is a ductile fracture.The deformed electrodeposited nickel undergoes a dynamic recovery recrystallization process after heat treatment.Electrodeposited nickel has the same pattern of texture orientation coefficient after each pass rolling without heat treatment and heat treatment,that is,heat treatment does not change the preferred orientation of the texture.