【作者】 黄瑞银；

【导师】 尹志民；

【作者基本信息】 中南大学 ， 材料物理与化学， 2013， 博士

【摘要】 本文结合中国铝业公司科技基金项目,以易拉罐罐体用3104铝合金材料为研究对象,从现场生产线上取样,采用显微硬度、拉伸力学试验、金相、X射线衍射、扫描和透射电子显微分析以及JMatPro软件模拟,对大规格铸锭特性及其均匀化处理、热轧、冷轧等全流程关键工艺控制因素进行研究,在此基础上,深入探讨了3104铝合金薄带成分-组织结构和性能之间的关系。获得了以下创新性成果：(1)3104铝合金大规格铸锭横截面上明显的宏观偏析,从铸锭表面到中心,各元素含量差别很大,Ti含量极差达到0.025%,Mg含量的极差达到0.34%,Ti元素的偏析规律与其他元素相反。从铸锭表层到中心,晶粒和初生化合物尺寸逐渐增大。3104铝合金大规格铸锭横截面上不同部位的微观偏析也是不均匀的,铸锭表层晶内Mg分布较均匀,而铸锭中部存在Mg的晶内偏析。大规格铸锭必须均匀化。(2)随均匀化温度的升高和时间的延长,晶粒内部的偏析逐步减少,显微硬度趋于一致；晶内发生(AlMnSi)和(AlMnFeSi)化合物析出,在590℃以下温度均匀化后析出不均匀,晶界和晶粒中心析出少；600℃以上均匀化后,析出相长大,密度减小,在晶内分布更为均匀。与此同时,晶粒边界区域的铝化物逐步溶解、熔断和球化,部分Al6(FeMn)相转变为α-Al12(MnFe)3Si相；大生产条件下3104合金铸锭最佳均匀化处理工艺为600℃/8-12h。(3)热轧过程过程中化合物的破碎效果非常明显,但热粗轧板坯在厚度和宽度方向上的组织还存在不均匀性,表层为完全再结晶组织,中心部位为热轧变形组织,中间过渡层为部分再结晶组织。经过热精轧后,热轧带材整个断面基本上是完全再结晶组织。(4)热精轧终轧温度和冷却速度对热精轧带材的组织有明显影响,终轧温度愈高、冷却速度愈慢,立方织构含量愈高。终轧温度为340℃和冷却速度为1℃/min时,立方织构含量从热粗轧板坯的30%左右提高到热精轧带材的60%以上。(5)冷轧过程中,随冷轧压下量增大,中部的第二相尺寸略有减小,冷轧后铸锭组织的不均匀性无法彻底消除；冷轧变形量、冷却速度等因素影响冷轧卷材织构的种类,终轧温度则无明显的影响。(6)冷轧变形量、终轧温度和薄带冷却速度对成品薄带织构含量和制耳率有很大影响,冷轧变形量越大,终轧温度越低,形变织构的α、β取向密度值越大,即形变织构含量越高,制耳率越大；在相同终轧温度条件下,缓冷比快冷的薄带β取向密度更大,制耳率更高；由于带材边部冷却不均匀,带材边部的取向线分布规律性不如中部,带材边部的制耳率高于中部。(7) Fe/Si比低和Fe含量低的3104罐体料具有更高的立方织构含量,制耳率更小,Al(Fe,Mn,Si)相含量更高,化合物颗粒更小,力学性能更合适,应用性能更好。更多还原

【Abstract】 Supported by the aluminum corporation of China technical fund,3104aluminum alloy strips used for canbody were investigated by the methods of micro-hardnessTesting, property testing, optical observation, SEM, TEM, XRD and JMatPro software simulation. The whole key processes for homogenization, hot rolling and cold rolling were studied. Based on this, the relationship between microstructures and properties was further discussed. The main results of the research are as follows:(1) Macro-segregation exists in the cross-sections of3104aluminum alloy largescale ingot, From the surface to the center of the ingot, The maximum differences of Ti contents reached0.025%, and the maximum differences of Mg contents reached0.34%, the rule of segregation is reverse,the grain and initial compounds size increase from surface to center of ingot. The micro-segregation was inhomogeneous at different positions, Mg distributed homogeneously in the surface of ingot and in-homogeneously in the center of ingot. It is necessary to homogenize for the largescale ingots.(2) With the increase of homogenization temperatures and the prolongation of homogenization time, the micro-segregation in the grains gradually decreased, the difference of micro-hardness gradually decreased.(AlMnSi) and (AlMnFeSi) phase precipitated in the grains. Homogenized below590℃, precipitates is small, and the distribution is uneven, in the grain and on the boundary is few. Homogenized up600"C, the intensity of precipitates decreased and the size of precipitates increased, the distribution is more homogenous. Meantime, the aluminide gradually dissolved and parts of Al6(FeMn) phase gradually transformed into a-Al12(MnFe)3Si phase. Under the production conditions, the proper homogenization treatment for3104ingot is600℃/8-12h.(3) The surface, center and interlayer of hot roughing sheet consisted of fully recrystallized, hot-rolling deformed and uncompletely recrystallized structure. The initial compounds were broken and distributed in-homogeneously. After hot finish rolling, the whole section of strip consisted of fully recrystallized structure.(4) The final rolling temperature and cooling rate had great and obvious effect on the structure of hot finishing trips. The final rolling temperature were higher and the cooling rate were lower, the content of cube texture was higher. When the final rolling temperature was340℃and the cooling rate was1℃/min, the content of cube texture increased from30%in hot roughing sheet into above60%in hot rolled trip.(5) During cold rolling, with the increase of cold rolling reduction, the size of the second phase decreased in the center of the material. After cold rolling, the structure inhomogeneity of the ingot can not be eliminated ultimately. The cold reduction and cooling rate affect the kinds of texture, but the final rolling temperature has no obvious effect.(6) The contents of clod rolling texture and earing were affected by deformation rate, final rolling temperature and cooling rate. With the increase of cold rolling reduction and the decrease of final rolling temperature, the intensity of α、β deformation texture is higher, the deformation texture and earing ratio increased. At the same final rolling temperature, the intensity of β texture and earing ratio were higher under the slow cooling rate. Due to the inhomogeneity of cooling rate, the earing ratio were higher at the edge of strip than at the center of strip.(7) The3104canbody with low Fe/Si ratio and Fe content have higher Cube texture, lower earing ratio, higher content of Al(Fe,Mn,Si) phase, smaller compound particles, appropriate mechanical properties and better performance properties.更多还原