Preparation Of Copper Clad Steel Composite Wire And Study Of Its Microstructure And Properties

High speed railway is a new mode of transportation in the development of modern society,its appearance meets the requirement of the current traffic development in the world,and develops very rapidly.High speed rail contact line as the most important part,its quality determines the stability and safety of high-speed railway.Due to its good conductivity,high strength,corrosion resistance,long lifetime and other advantages,copper clad steel composite wire has great application prospect in the field of contact line.This paper introduces two methods: drawing compound method and horizontal continuous casting method,and analysis the microstructure and properties,so as to prepare samples of copper clad steel wire from different drawing deformation,and perform heat treatment on the samples at the different annealing conditions.By studying on the changes of composite lines and transverse and longitudinal section of the microstructure,diffusion layer thickness,interface bonding strength,the micro hardness and tensile strength of copper-steel interface,elongation and electrical conductivity,we can draw a conclusion about how the drawing deformation and annealing process affect the microstructure and properties.By self-designing and manufacturing of horizontal continuous casting of CCS equipment,CCS wire that the diameter is 12 mm has been prepared continuously by using the equipment and measured the interfacial diffusion layer thickness is 2.5?m,the interfacial bonding strength is 29.5 MPa.In addition,copper clad steel wire which diameter is 7mm has been prepared by drawing composite.The microstructure of Cu,Fe in cross-section decreases gradually until the boundaries blurred,the longitudinal-section microstructure is stretched along drawing direction and showed fibrous rheological type.Drawing after annealing,along with the increase of annealing temperature and the extension of time,microstructure of cross and longitudinal section were increased.Compared with the annealing time,the effect of annealing temperature on the microstructure is more obvious.The conductivity and elongation of CCS wire are decreased with the increase of deformation,the tensile strength is increased.With the increase of annealing temperature and time,the elongation increases,the tensile strength decreases oppositely.The conductivity increases with the increase of annealing time,and the conductivity increases first and then decreases with the increase of annealing temperature.The microhardness of copper and steel increases with the increase of deformation.After annealing,the microhardness of the copper and steel decreased significantly.With the increase of the annealing temperature and the annealing time,the microhardness of the copper and steel in the same position of the interface decreased gradually.With the increase of the annealing temperature and annealing time,the thickness of the diffusion layer increases and the interfacial bonding strength increases.With the increase of annealing temperature and time After reaching the recrystallization temperature of CCS wire,the thickness of the diffusion layer and the interfacial bonding strength are almost constant.Considering the combination of the diffusion layer and the interface,the optimal annealing process is annealing 2 h at 750 ?.