| In order to meet China's economic development, high-speed electric trains are growing. In order to improve the quality of locomotives by the stream, we must improve the hanging tension carrying current capacity and stability of contact wire. This requires contact wire material not only has good conductivity, but also has a high strength and high resistance to softening temperature. At present, CuAg alloy contact wire is widely used to meet the needs of low-speed train operation. However, to meet the 350km / h and higher train speed, we must develop a new type of contact wire. Based on this background, the forming process of CuSn alloy was studied in detail in this paper. The main study framework will mainly focus on alloy design, electrolytic polishing, organizational performance, and EBSD.Alloying of materials was studied in the article, in order to meet the needs of mass production in factories. The best amount of CuSn alloys containing Sn has been determined to be 0.3%, by analyzing mechanical properties and microstructure morphology of alloys with different Sn-containing. Because of the actual loss of elements in the smelting process, so control the composition range of 0.3% ~ 0.55%.Mechanical polishing tends to easily cause deformation of the surface layer of the specimen.The electro-polishing parameters of high-speed electric railroad CuSn alloy contact wire were studied in this paper. This paper is based on the principle of electro-polishing and anodic polarization curves as a reference. The optimum electro-polishing parameters of CuSn alloy contact wire were finally defined by improving of electro-polishing apparatus. The results show that: at room temperature conditions, we can get an excellent CuSn alloy contact wire metallographic by 1.5 ~ 1.9V polishing voltage and 10 ~ 15 minutes polishing time.The forming technology of high-speed electrified railway CuSn alloy contact wire was studied in this paper. The hot and cold forming test of CuSn alloy contact wire rod blanks were studied by different forming technology. And the performance differences of product lines were compared in this paper. The results show that: The optimum forming technology is upward continuous casting→continuous extrusion→continuous rolling→continuous drawing. The tensile strength reaches to 538MPa, elongation is 12%, electrical resistivity is 0.02360Ω.mm~2/m, alternating bending is 9,torsion test is 11 circle. Combination property have reached or exceeded the TB / T 2809-2005 standard. And it can meet the application requirements of high-speed electrified railway.The electron backscatter diffraction (EBSD) analysis of alloys was studied in this paper. The results showed that: the law of deformation grain orientation, texture changes and the distribution of grain boundary are as follows.The extruding CuSn alloy only has <100> silk texture with 30% cold drawing deformation. When the deformation increased to 60%, the grain orientation gradually segregated in [111] direction. Continued to increase to 75% in deformation, the stability of <100> and <111> silk structures can be found. Because of shearing stress the texture component changed from <100> to <111>.And a little <112> texture can be found. The stability of <100> and <111> silk structures also can be found in alloy with different annealing temperature.There were more and more LAGBs(<8°), with the increase in the amount of drawing deformation.The peak is 2.95°. When the deformation increased to 75%, because of the microstructure evolution mechanismthe, the number of HAGBs(59°～61°) was decreased significantly. CSL grain boundarys mainly focus onΣ3,Σ9,Σ27,Σ29 these four locations. The content ofΣ3 from 79.56% up to 81% and eventually rose to 83%. As the annealing temperature lifting, the number of small-angle grain boundaries increase rapidly. Orientation distribution appeared very strongΣ3(compound twin),Σ9(Secondary compound twin) andΣ27(cubic compound twin). The sum of them was up to 90.35% at last. LowΣCSL grain boundary had strong binding force and low interface energy. They can reduce and avoid the source of micro-cracks generation and impede the expansion of micro-cracks.
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