【作者】 宋练鹏；

【导师】 尹志民；

【作者基本信息】 中南大学 ， 材料物理与化学， 2008， 博士

【摘要】 研究开发了多种适用于地铁、轻轨和高速列车变频调速交流异步牵引电动机转子的Cu-Zn-Cr-Zr-RE导条合金、Cu-Cr-Zr-RE端环合金和Cu-A1-Fe-Ni-（Zr+RE）护环合金及导条与端环焊接用Ag-Cu-Zn-RE-X配用焊丝,并研究了合金相应的熔炼铸造、热挤压、热锻及时效处理等工艺制度及这些过程中组织和性能变化规律等一系列问题。采用硬度测试,室温与高温拉伸、电阻率测量、X射线物相分析（XRD）、金相（OM）、电子显微分析方法（TEM、SEM）和热模拟,运用Deform软件进行的模型数学计算等多种方法和手段,采用实验和理论相结合的方法,研究了新型铜合金在整个制备环节中的性能和组织变化规律,获得了下列重要结论:1.利用Cu-Zn合金固溶体基体电导性能随Zn含量的变化连续稳定可调的特性,采用微合金化技术和挤压-在线淬火-冷拉成型-时效的形变热处理技术,研制开发了一种高强中导Cu-Zn-Cr-Zr-RE合金导条,最佳制备工艺为挤压-在线水淬-30～40%冷拉变形-450℃/4h时效,在此条件下,合金的室温力学性能和电学性能分别为σ_b=467MPa,σ_0.2=390MPa,δ₅=20.8%,（?）r=64.6%IACS。350℃试验温度下σ_b和σ_0.2仍分别保持在274MPa和250MPa左右,满足了轨道交通用大功率调频调速异步牵引电动机转子组件的设计要求。2.设计并实现了导条热挤压-在线淬火,解决了超长件导条挤压坯在线淬火的难题,保证了后续冷变形时效这种形变热处理强化技术的实施。3.研究合金的强化机制包括固溶强化、析出强化和形变热处理强化。形变热处理工艺可大大提高合金时效后的最终强度,冷拉后的合金时效过程中受到析出和再结晶过程交互作用的影响。析出的第二相粒子不仅强化了基体而且一定程度上抑制了再结晶的进行,从而使合金的强度进一步提高。4.冷变形-时效过程中影响合金电导率变化的主要因素包括过饱和固溶体的分解和析出以及回复-再结晶过程,合金的高导电性来源于时效后高电导率基体与析出粒子组成的弥散型复相结构。5.对不宜采用形变热处理技术强化的高强高导大规格端环铜合金,采取相对较高的铬、锆含量并结合强化固溶-时效工艺,可以获得较好的综合性能。铜合金端环最佳制备工艺为热锻-980℃/1h强化-450℃/4h时效,其中热锻工艺为始锻温度控制在850℃,终锻温度不低于650℃,道次锻造变形量约40%。在此条件下,合金的室温力学性能和电学性能分别为σ_b=388MPa,σ_0.2=315MPa,δ₅=27.8%,σr=84.5%IACS。在350℃试验温度下σ_b和σ_0.2仍分别保持在200MPa和165MPa以上。研制的端环满足了轨道交通用大功率调频调速异步牵引电动机转子组件的设计要求。6.采用微合金化技术和热锻-稳定化退火处理工艺开发了一种Cu-Al-Fe-Ni-Zr-RE高强高韧大规格铜合金护环,最佳制备工艺为热锻-650℃/1h稳定化退火处理,其中热锻工艺为始锻温度控制在880℃,终锻温度不低于680℃,道次锻造变形量约40%。在此条件下,护环合金室温力学性能分别可达:HB=226,σ_b=763MPa,σ_0.2=456MPa,δ₅=20.3%。满足了轨道交通用大功率调频调速异步电动机转子护环的性能要求。7.依据高强高导微合金化原理和界面润湿理论,设计并优化了配用焊丝的合金成分,采用中频熔炼-铸造-挤压-拉丝-退火技术制备了用于铜合金转子导条-端环焊接的配用焊丝。配用焊丝的熔点、润湿性、焊接接头力学性能满足导条与端环焊接构件的设计要求。8.通过理论计算与实际模拟相结合,分析了焊接过程中导条/端环温度的变化,在此基础上研究了实际焊接过程中导条与端环材料组织和性能的演变规律,为转子部件的焊接提供了理论与实验的依据。9.实际焊接过程中,焊接接头分为端环区、焊缝区和导条区,焊缝组织为共晶组织;端环一边的组织会发生时效析出相的回溶,硬度和强度降低;导条靠近焊接接头的部分则会发生再结晶和时效析出相的回溶,硬度和强度也降低,离焊缝的距离越远,其焊接时经受的最高温度越低,硬度、强度性能下降越小。10.导条-端环焊接组件上焊缝本身的强度以及结合面的强度达到了大功率异步牵引电动机转子部件的设计要求。11.为株洲南车电机股份有限公司、湘潭电机股份有限公司等轨道交通牵引电机国产化基地提供了1350套大功率调频调速异步牵引电动机转子组件,研制开发的铜合金导条、端环和护环荣获国家重点新产品称号。更多还原

【Abstract】 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.更多还原