【作者】 付亚波；

【导师】 殷国茂； 李廷举；

【作者基本信息】 大连理工大学 ， 材料加工工程， 2011， 博士

【摘要】 铜合金因具有高耐蚀、高强度、高导电等性能而被广泛应用。在铜基体中添加镍、铁和锰元素,制备具有良好耐腐蚀性能的BFe10-1-1合金,可运用于海水淡化和船舶等行业。在铜基体中添加微量铬和锆元素,形成具有高强度和高导电性能的Cu-Cr-Zr合金,可运用于高速铁路等行业。传统BFe10-1-1管材的制备工艺复杂,成品率不足40%,市场竞争力较弱,需要开发一种短流程的制备工艺。时速超过350km高铁所需Cu-Cr-Zr接触导线也需要用短流程工艺制备,如京沪高铁要求的接触导线强度为600MPa以上、导电率80%IACS以上和单根盘重2500kg,传统Cu-Cr-Zr合金的真空熔铸及加工方式无法满足要求。因此,研究一种新技术制备这两种铜合金管线材,具有重要意义。电磁搅拌技术作为细化晶粒、消除偏析的重要手段,可显著提高BFe10-1-1和Cu-Cr-Zr铸坯的质量。行星轧制技术能够实现超长铸坯的大变形,而且能依靠动态再结晶改善组织性能。本文通过水平连铸及行星轧制短流程工艺制备BFe10-1-1管材的研究,分析了旋转磁场和行星轧制对材料性能的影响,然后把该工艺运用于Cu-Cr-Zr接触导线的制备。本文研究了旋转磁场对BFe10-1-1管坯的表面质量、组织和晶粒尺寸等性能的影响,结果表明：管坯表面的平均粗糙度Ra(μm)降低了65.87%；柱状晶组织消失,管坯上下端组织均匀,晶粒在横断面和纵断面的生长方向均被打散；管坯晶粒得以细化,平均晶粒尺寸为0.55mm；元素分布均匀。BFe10-1-1管行星轧制变形的研究表明：再结晶细化晶粒的效果显著,管坯的抗拉强度为293MPa,硬度为99HB,断面收缩率为26%,具有良好的塑性变形性能；轧制后90%管坯的偏心率保持在2.8%—6.0%,优于挤压穿孔工序的偏心率,可有效防止拉伸过程的不均匀变形。拉伸变形通过了多次实验验证。短流程工艺制备BFe10-1-1管获得成功。通过研究BFe10-1-1管的塑性变形规律发现,塑性变形中同时存在固溶强化、形变强化和细晶强化三种机制,固溶强化、形变强化是引起强度增加、塑性降低的主要原因；而细晶强化在提高强度的同时也提高了塑性,只是对提高塑性的贡献率没有固溶强化和形变强化对降低塑性显著,三者叠加的结果使材料整体性能表现为强度提高、塑性降低。针对时速超过350km高铁所需特殊性能接触导线,将短流程工艺运用于Cu-Cr-Zr接触导线的制备。研究了非真空条件的水平电磁连铸技术,发现施加旋转磁场使Cu-Cr-Zr棒坯的铸造温度降低了22℃,实现了低温铸造,是非真空条件熔铸棒坯的关键因素。通过现场多次实验,确定了非真空条件下水平电磁连铸技术制备φ87mm、长度45m的Cu-Cr-Zr棒坯工艺：铸造速度为108 mm/min,铸造温度为1255-1260°C,冷却水流量1.9 m3/h,旋转磁场参数为50 A、30Hz。棒坯表面无裂纹,凝固组织均匀,内部无气孔和夹渣,晶粒得以细化,元素分布均匀。长度45m的Cu-Cr-Zr棒坯进行了行星轧制,轧制变形使棒坯完成了动态再结晶,平均晶粒尺寸为0.04mm,抗拉强度为244.04 MPa,伸长率为29.31%,导电率为75.10%IACS。轧制后棒坯的固溶工艺为860°C×1h。三道次冷加工变形后棒坯的时效工艺为385℃×2h。经过水平电磁连铸、行星轧制、固溶处理、冷加工和时效处理工艺,制备的成品导线的抗拉强度达到610 MPa、导电率85%IACS、单根盘重2500kg。强度不断提高是细晶强化、固溶强化、时效强化和形变强化共同作用的结果。在合作工厂制备了200吨高强高导Cu-Cr-Zr接触导线,于2010年10月3日在京沪高铁线上通过了高铁史上最高运营时速486.1公里的实验,新型高强高导接触导线的开发获得成功。更多还原

【Abstract】 Copper alloys are widely used because of its excellent properties, such as high corrosion resistance, high strength and high electric conductivity and so on. Copper alloy CuNi 1 OFe 1 Mn added Ni, Fe and Mn elements in the copper matrix is widely applied to desalination of sea water, marine ship and other industries due to its property of high corrosion resistance. Cu-Cr-Zr alloy added Cr and Zr in the copper matrix is applied to high-speed railway due to its properties of high strength and electric conductivity.There is an urgent need to study a short process technology of CuNi10FelMn tubes as the traditional preparation technology is complicated, and the rate of finished products is less than 40%, so the products are less competitive. The researches indicate that the short process technology can also produce the contact wires installed on the high-speed railway with 350km/h speed, for instance, the properties of contact wires used in the Beijing-Shanghai high-speed railway are demanded that the tensile strength is above 600MPa, and the conductivity is above 80%IACS and the single plate weight is above 2500kg. Therefore, traditional vacuum casting and processing methods of Cu-Cr-Zr alloys must be changed. In a word, it is significant to study a new technology for preparing copper alloys as mentioned above.Electromagnetic stirring technology plays a significant role in improving the quality of CuNi10FelMn and Cu-Cr-Zr alloy due to grains refining and elimination of segregation. A large deformation of long billets can be achieved by planetary rolling technology and improvement of the structural properties can be realized by dynamic recrystallization. This paper studied the short process technology combining the horizontal continuous casting with planetary rolling in the preparation of CuNi10FelMn tubes, explored the effect of the rotating electromagnetic field (REF) and planetary rolling on the material properties, and then the contact wire of Cu-Cr-Zr alloy was prepared by the short process technology.This paper studied the influence of REF on the surface quality, structure and grain size of CuNi10FelMn billets and so on. The results indicate that:the average roughness Ra (μm) of tubes surface is decreased by 65.87%, and the columnar grain structure of top and bottom area is disappeared, and the grain size is refined obviously, which is 0.55mm. The distribution of elements is even. The studies of planetary rolling of CuNi10FelMn tubes indicate that there is a good property of plastic deformation as the grain size is refined obviously by dynamic recrystallization, and the tensile strength is 293MPa, and the hardness is 99HB, and the percentage of area reduction is 26%. The eccentricity of 90% tubes after planetary rolling is remained at 2.8%-6.0%, which is better than that of the extrusion process and can effectively prevent the uneven deformation during the drawing deformation. The drawing process has successfully passed the test many times, so the short process technology can be successfully used for producing the CuNilOFelMn tubes. The studies of the plastic deformation indicate that:there are three mechanisms such as solution strengthening, deformation strengthing and refined grain strengthening, and the increase of strength and the decrease of plasticity are mainly caused by the solution strengthening and deformation strengthing, however, the refined grain strengthening not only improves the strength but also improves the plasticity, only the contribution rate of raising the plasticity is not more remarkable than that of the solution strengthening and deformation strengthing. As a result, the whole properties of the tube show that the plasticity is reduced and the strength is increased by three methods.The short process technology is applied to produce the contact wires of Cu-Cr-Zr alloy in order to meet the special needs of high-speed railway over 350km/h speed. The paper studied the horizontal electromagnetic continuous casting under non-vacuum conditions, the results indicate that the low-temperature casting by decreasing 22℃can be achieved by REF, which is a key factor for non-vacuum conditions. The casting parameters of Cu-Cr-Zr alloy billet with a length of 45m, diameter ofΦ87 are:casting speed is 108mm/min, and casting temperature is 1255℃-1260℃, and the cooling water flow is 1.9 m3/h, the parameters of REF are that the current intensity is 50 A and the frequency is 30Hz. There is no crack on the billet surface and no porosity and slag on internal, and the solidification structure and the distribution of Cr, Zr, Cu of are even, and the grain refinement is significant.The Cu-Cr-Zr billet with length of 45m can be rolled by planetary rolling technology, which makes the bar achieve dynamic recrystallization. The average grain size of the billet’s bar is 0.04mm, the tensile strength of which is 244.04 MPa, elongation of which is 29.31%, and conductivity of which is 75.10% IACS. The solution parameters of rolled bar are 860℃×1h. The aging parameters after cold deformation with three passes are 385℃×2h. After the processing of horizontal electromagnetic continuous casting, planetary rolling, solution treatment, cold deformation and aging treatment, the properties of finished contact wire are that the tensil strength is 610 MPa, and the conductiviey is 85%IACS. Increasing of tnesile strength is depended on the refined grain strengthening, solution strengthening, aging strengthening and deformation strengthening. The finished contact wires of 200 tons have been produced for Beijing-Shanghai high-speed railway at co-cooperation workshop, and they have been successfully passed the experiment of the highest operating speed of 486.1 km/h in the high-speed railway history on October 3,2010. A new contact wire of high strength and high conductivity achieves success.更多还原