Preparation And Its Basic Researches On Copper Alloy Parts Of Draw Electric Motor Rotator Used For Orbit Traffic

Cu-Zn-Cr-Zr-RE conducting bar alloy and Cu-Cr-Zr-RE end ring alloy and Cu-Al-Fe-Ni-(Zr+RE) shroud ring used for high power asynchronous traction electromotor rotor of subway and light railway and high-speed railway and Ag-Cu-Zn-RE-X alloy welding wires applied to welding conducting bar and end ring are developed,and the procedures of alloy melting and casting,thermal extrusion,forging hot and aging and the change-laws of microstructures and properties are studied.hardnesses,tensile properties at room temperature and at elevated temperatures,resistivities of above alloys are measured,and microstructures are studied by X-ray diffraction(XRD),optical microscopy(OM),electronic microstructure analysis(SEM,TEM).Thermal simulate test and mathematics analysis by Deform program are completed.On the base of linking theory with practice,important conclusions can be summarized as follows:1.A Cu-Zn-Cr-Zr-RE alloy conducting bar with high strength and medium conductivity is developed by using micro-alloying and deformation heat treatment technology of extrusion—on-line quench—cold-drawing—aging,according to the characteristics of the conductivity of Cu-Zn alloy solid solution can be adjusted continuously with the change of Zn content,The optimal preparation process of conducting bar is extrusion—quench—cold-drawing(30⁴0%)—aging(450℃/4hours).The tensile strengthσ_b,yield strengthσ_0.2, percentage elongationδ₅ and conductivityσ_r at room temperature achieved 467MPa,390MPa, 20.8%and 64.6%IACS,respectively.σ_b andσ_0.2 can hold 274MPa and 250MPa at 350℃, respectively.and which meet the needs of design of high-power frequency-modulated and speed-controlled asynchronous traction electromotor rotor.2.The technologies of conducting bar is extruded and on-line quenched are designed and achieved,the problem of on-line quenching to over-long conducting bar extrusion base is solved,which guarantee the implement of technology of cold-deformation and aging.3.The strengthen mechanism of alloy excludes solid-solute strengthening,deformation heat treatment strengthening and precipitate strengthening,the alloy strength after aging can be raised obviously by deformation heat treatment,the alloy properties after cold-drawing are mutual affected with precipitate and recrystallization during aging,precipitation of the second phase not only strengthen body but also restrain recrystallization on some extent,which further raise the alloy strength.4.The primary factors of affecting alloy conductivity during cold deformation and aging exclude dissolve and precipitation of supersaturated solid solution and processes of reversion and recrystallization,high-conductivity of alloys come from disperse and duplex phase structure with high-conductivity matrix and precipitation particles.5.The large-scale end ring alloy unsuited to deformation heat treatment strengthening can acquired optimal properties by using higher Cr and Zr content and strengthening solid-solution and aging,The optimal preparation process of copper alloy end ring is forge hot—strengthening solution(970℃/1h)—aging(450℃/4h).the state temperature of forge is 850℃,and the end temperature is over 650℃,deformation extent is about 40%.On the above condition,the mechanical and electrical properties of alloy at room temperature areσ_b=388MPa,σ_0.2=315MPa,δ₅=27.8%,σ_r=84.5%IACS,σ_b andσ_0.2 can hold 200MPa and 165MPa at 350℃,respectively,the Cu-Cr-Zr-RE alloy end ring developed meet the needs of high power asynchronous traction electromotor rotor for orbit traffic.6.A large-scale Cu-Al-Fe-Ni-(Zr+RE) shroud ring with high-strength and high-toughness is developed by using micro-alloying design and thermal-forge and stabilization annealing,The optimal preparation process of copper alloy shroud ring is forge hot—stabilization annealing(650℃/1h).the state temperature of forge is 880℃,and the end temperature is over 680℃,deformation extent is about 40%.On the above condition,the mechanical properties of alloy at room temperature are HB=226,σ_b=763MPa,σ_0.2=456MPa, 85=20.3%,respectively,which meet the needs of property of high-power frequency-modulated and speed-controlled asynchronous traction electromotor rotor shroud ring.7.The composition of Ag-Cu-Zn-RE-X alloy welding wire is deigned and optimized according to high strength and high conductivity micro-alloying principle and interface moist theory,welding wires applied to welding conducting bar and end ring are developed by using the technology of intermediate frequency melting—casting—extrusion—drawing—annealing. Melting point,moist property of welding wires and mechanical property of welding joint can satisfied the demands of the welding parts of bar and end ring.8.The changes of temperature of bar and end ring in the process welding are analyzed by linking theoretical calculation with practical simulation,evovement-laws of microstructures and properties of bar and end ring in the process of practical welding are studied,which provided the theory and practice basis for welding of the rotor part.9.The joint includes end ring area,the welding seam zone and bar area,the structure of weld line is eutectic,the structure on the end ring produce resolution of precipitation phase after welding,which result in hardness and strength lowing,the structure of bar near the joint is also,but the farther from the weld line is,the higher the hardness and strength are.10.The strength of the welding seam of the welding part and interface strength of bar and end ring meet the needs of high power asynchronous traction electromotor rotor.11.The copper alloy bar and end ring and shroud ring developed are given the title of national key new product,and 1350 sets rotor parts have been provided for Zhuzhou CSR Electric Co.Ltd.and Xiangtan Electric MFG.Co.Ltd.