The Analysis Of The Copper-Steel Dissimilar Metal Connection Process Of Permanent Cathode Plate Conducting Rod And The Property Of Its Joints

Permanent cathode copper electrolysis technology is using high rigidity and well toughness stainless steel plate to make the cathode,replacing the traditional starting sheet.It can save the stripping and processing of mother board and the starting sheet,and cathode is recycled,which can not only shorter the process flow,but also lower the cost of the production.Permanent cathode copper electrolysis technology has high productivity,long life span,and high output,and it's recycled.It is particularly suitable for large scale electrolysis producing.Following the development of copper electrolysis technics,it is advisable to use it in our country;nowadays,all of the large scale copper electrolysis projection is using the permanent cathode used in copper electrolysis technology.However,how to make the high-powered cathode's conductor pole,which the core technique of the permanent cathode copper electrolysis technology is still a problem in our country;therefore,having the ability to make the cathode's conductor pole has important meaning in project and economy.Because most permanent cathode conductor pole use the structure of copper clad steel,weld is inside the structure,people can't see the integrate area;what's more the physical properties between copper and steel have huge differences,during the process of welding may have the defects like distortion and crevice;therefore,using the traditional welding technique can hardly suit for the welding of special structure.The temperature of high-frequency induction brazing is lower,it's easier to reach and control the temperature of inside welding,and the alloy element of solder can effectively avoid the welding flaws.Therefore,this paper is about using the method of high-frequency induction to do the simulation brazing experiment of permanent cathode conductor pole.To focus on this simulation experiment,first,this paper chooses the Sn-Cu as the martial of the experiment,and coat it on the martial before the experiment;secondly,this paper has five parts,eighteen group of technic experiments,it concludes five important technic parameter of copper-steel framework in the welding experiment like heat current,and the time arrangement;then use the light microscope to Scan Electron Microscope,Energy Disperse Spectroscopy,X-ray Diffraction,and analyse the microcosmic organization,phase' type,and the distributing of elements,meanwhile,using the Intelligent Metal Resistivity Tester?Electronic Universal Testing Machine?Microhardness Tester test the conductivity,rigidity,toughness.To find the different effect on the joint properties by ananlyse the samples' different propertiesIt can be conclude from the result of light microscope,scanning electron microscope and Energy Disperse Spectroscopy that there is no flaws in welded first kind workpiece and the interface is clear;the joint can divided into copper side reaction diffusion layer,middle layer and steel side reaction layer.And the results can indicate that copper side reaction diffusion layer is thicker than steel side reaction layer and the interface of copper side reaction diffusion layer is smooth.After heating at high temperature,the twin structure appeared in copper after annealing and because of stainless steel separating out carbide,stainless steel appeared flocculus.Secong king workpiece as simulated workpiece using stainless to coate copper.There is no flaws in welded second kind workpiece and the joint only have one reaction diffusion layer and the interface to copper is not clear but to stainless steel is clear;because of heat concentration,the tin layer is fully diffused into the copper side parent material.It can be found through the result from testing conductivities of specimens that there are two main factors that influence the conductive properties of the joints.Firstly,higher heater current and longer heating time will make holding time longer,which means that the conductive properties of specimens shows decreased trend if the weld heat input is too large.It is because that Cu and Sn which are under high temperature for a long time will produce Cu3 Sn during welding workpieces.This Copper tin compound can hinder the directional velocity of career,and lead to the decrease of the conductivities of specimens.Secondly,less joint defects and better compactness will lead to better conductivities,which is because that poor joint continuity and uneven contact area can definitely influence the current flow between high and low electric potential.It can also be found through the result from testing joint strength and joint hardness that the tensile strength of the second species of workpieces is obviously better than the tensile strength of the first species of workpieces,which means that coating structure can centralize heat internally during welding and lead to adequate metallurgical reaction of copper-tin steel,while producing more brittle hard phase.Synthesizing the results of the tests and examination above,using the optimum technology parameter in the thesis can produce the copper-steel soldered joints which have artistic welding appearances,excellent connection strength,and great conductive properties.