铸轧铝板坯用Cu-0.23Be-0.84Co合金热变形行为及数值模拟研究

发布时间：2018-01-11 15:10

本文关键词：铸轧铝板坯用Cu-0.23Be-0.84Co合金热变形行为及数值模拟研究　出处：《河南科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：目前,双辊连续铸轧生产铝板坯工艺使用的辊套主要为钢辊套,由于钢辊套的导热率较低,导致熔体的凝固速度慢进而影响铸轧速度和产品质量。因此,提高铸轧速度就必须提高熔体的凝固速度,实现这一目标有效的方法是开发高导热性辊套材料。铍铜合金在所有铜合金中,具有高的强度硬度、高的导电导热性,高的蠕变强度、耐磨耐蚀性、无磁性和冲击不产生火花等综合性能,尤其是铍含量在0.2-0.6wt.%的低铍高导铍青铜合金,是提高铝板坯连续铸轧效率和质量过程中实现辊套材料以铜代钢最具潜力的选材。目前,国内外针对铍铜合金的研究主要集中在铍含量在1.6-2.0wt.%的高强铍青铜,而针对某些服役工况以高的导热/电性能为主的低铍铜合金(铍含量0.2-0.6wt.%)的相关研究和应用鲜有报道。本文以Cu-0.23Be-0.84Co合金为研究对象,研究了该合金的制备工艺以及其热力学性能;采用Gleeble-1500热模拟试验机对Cu-0.23Be-0.84Co合金进行热压缩变形试验,研究了Cu-0.23Be-0.84Co合金的流变热变形行为,分析了不同变形条件对合金流变应力的影响,计算了合金的热变形激活能并建立了Cu-0.23Be-0.84Co合金的热变形本构方程;根据动态材料模型加工图理论构建了Cu-0.23Be-0.84Co合金的热加工图,揭示了合金热变形过程中微观组织变化规律,获得了Cu-0.23Be-0.84Co合金最佳热加工工艺参数,为该合金的实际热加工过程提供理论指导;借助DEFORM-3D有限元软件,结合本文研制的Cu-0.23Be-0.84Co合金材料性能参数,重点分析了铸轧温度、铸轧速度等参数对Cu-0.23Be-0.84Co合金辊套温度场及应力场分布的影响规律,并同目前常用的钢辊套进行了对比分析。研究结果表明:温度的变化对Cu-0.23Be-0.84Co合金的导热系数影响较小,其导热系数平均值为239 W/m·K,大约是钢材导热系数的十倍。在热变形过程中,Cu-0.23Be-0.84Co合金的热激活能为419.480k J/mol,热变形时的流变应力模型为:65.49 22.25??=e[sinh(0.0041?)]exp(?419480/8.31T)。构建的Cu-0.23Be-0.84Co合金热加工图表明:当变形量为0.1~0.3时,合金热压缩变形安全区较大,主要是中温高应变速率区和高应变速率区;当变形量为0.4~0.6时,合金热压缩变形主要存在一个安全区,变形温度450~725℃,应变速率为0.7~10s-1区域。Cu-0.23Be-0.84Co合金辊套数值模拟结果表明:在铸轧过程中,辊套在接触区内的热量主要集中在表面层附近,越靠近表面层,温度越高,而辊套内侧温度变化较小;随着轧制温度的升高,铜辊套在铸轧区内最高温度越来越高,但最高温度变化幅度越来越小,当铸轧温度由650℃升高到700℃时,铸轧区内辊套最高温度由328℃升高到365℃,其中在680℃时辊套最高温度为364℃。当铸轧速度从0.8m/min增加到2m/min时,辊套内外表面最大温差由257℃升高到265℃。表明铸轧速度对辊套内外温差影响较小;在铸轧速度为2m/min和铸轧温度为680℃条件下,导热率为239W/m?k的铜辊套表面最高温度为245℃,而导热率为25W/m?k的钢辊套表面温度为305℃,表明铸轧辊套表面的温度场分布受导热率的影响较大;在铸轧过程中,Cu-0.23Be-0.84Co合金辊套的压应力主要集中在铸轧辊套的外表层。
[Abstract]:At present, the use of technology for the production of aluminum slab continuous casting and rolling double roller set mainly for steel roller, steel roller due to the heat conduction rate is low, resulting in the slow solidification rate of the melt and the effects of casting speed and product quality. Therefore, improving the casting speed must improve the solidification rate of the melt, the realization of effective methods the goal is to develop high thermal conductivity material of roll sleeve. Beryllium copper alloy in all copper alloy with high hardness, strength, high conductivity, high creep strength, wear resistance and corrosion resistance, no magnetism and shock does not produce spark comprehensive performance, especially in the low 0.2-0.6wt.% content of beryllium beryllium high conductivity beryllium bronze alloy, continuous casting and rolling material is to improve the efficiency and quality in the process of implementing material roller to copper and steel most potential aluminum slab. At present, the high strength beryllium bronze research for beryllium copper alloy mainly concentrated in beryllium content in 1.6-2.0wt.%, According to the service condition in some low beryllium copper alloy high thermal / electrical properties of (beryllium content 0.2-0.6wt.%) related research and application is rarely reported. Taking Cu-0.23Be-0.84Co alloy as the research object, study the preparation process of the alloy and its thermodynamic performance test; hot compression deformation of Cu-0.23Be-0.84Co alloy using Gleeble-1500 simulated machine hot deformation behavior of Cu-0.23Be-0.84Co alloy was investigated by rheological thermal analysis, the influence of deformation conditions on the stress calculation of alloy alloy rheological, thermal deformation activation energy and the establishment of Cu-0.23Be-0.84Co alloy thermal deformation constitutive equation; processing map according to the dynamic material model theory to construct the processing map of Cu-0.23Be-0.84Co alloy, reveals the change in the process of microstructure deformation of alloy, obtained the best thermal processing of Cu-0.23Be-0.84Co alloy for the parameters. To provide theoretical guidance for actual thermal processing of the alloy; by using DEFORM-3D finite element software, combined with the performance parameters of Cu-0.23Be-0.84Co alloy materials developed in this paper, focus on the analysis of the influence of casting temperature, casting speed distribution parameters such as stress of Cu-0.23Be-0.84Co alloy roller and the temperature field, and with the commonly used steel roll sleeve a comparative analysis. The results show that temperature change has little effect of thermal conductivity of Cu-0.23Be-0.84Co alloy and its thermal conductivity was 239 W/m - K, is about ten times. The thermal conductivity of steel during hot deformation of Cu-0.23Be-0.84Co alloy, the thermal activation energy of 419.480k is J/mol, the thermal deformation of the rheological stress model 65.49: 22.25?? =e[sinh (0.0041?)]exp (? 419480/8.31T). Cu-0.23Be-0.84Co alloy hot processing map construction shows that when the deformation is 0.1~0.3, compression deformation zone alloy The larger, mainly variable rate and high strain rate in high temperature; when the deformation rate is 0.4~0.6, compression deformation of alloy mainly exists a security zone, deformation temperature of 450~725 DEG C, the strain rate of 0.7~10s-1.Cu-0.23Be-0.84Co alloy roller numerical simulation results show that in the process of roll casting, roll sleeve within the contact area of the heat is mainly concentrated in the near surface layer, the more close to the surface layer, the higher the temperature, and the roller inner temperature change less; with the increase of rolling temperature, copper sleeve in cast rolling zone and the highest temperature is higher, but the highest temperature change range is more and more small, when casting temperature. From 650 degrees to 700 degrees, in the cast rolling zone and sets the highest temperature increased from 328 C to 365 C, which is at 680 DEG C and sets a maximum temperature of 364 degrees. When the casting speed increases from 0.8m/min to 2m/min, and set the maximum temperature difference between inner and outer surface of from 257 DEG C to 265. C. Show that the casting speed of roller temperature difference between inside and outside influence small; in casting speed of 2m/min and the casting temperature is 680 DEG C under the condition, the thermal conductivity is 239W/m? The highest temperature of copper roller surface K is 245 DEG C, and the thermal conductivity of 25W/m? K steel roller surface temperature is 305. Show that the casting roller surface temperature distribution by thermal conductivity has great influence; in casting process, Cu-0.23Be-0.84Co alloy roller pressure stress mainly concentrated in the surface layer of cast roll sleeve.

【学位授予单位】：河南科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG146.11

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