【作者】 史向阳；

【导师】 赵红亮；

【作者基本信息】 郑州大学 ， 材料加工工程， 2012， 硕士

【摘要】 铝塑复合板具有良好的耐候耐蚀性、防火防潮性和易加工成型性等优点,广泛用于幕墙装饰、广告招牌等。铝板基作为铝塑复合板的重要组成部分,其产品质量好坏直接影响到铝塑复合板的使用寿命。传统的生产铝塑复合板用铝板基的方法是采用金属铸锭重熔及热轧冷轧等多道序工艺,生产过程繁琐、生产效率低、浪费能源。近年来,随着铝板带生产技术的进步,生产铝塑复合板用铝板基逐渐采用电解铝液直接铸轧的短流程生产工艺。与传统方法相比,电解铝液直接铸轧生产铝塑复合板用铝板基具有工艺流程短、生产成本低、生产效率高等优点。但是采用电解铝液直接铸轧生产仍存在一些技术难题：电解铝液温度过高,结晶时有效形核率低,同时铸轧冷却速度过快,导致铸轧板坯成分偏析、第二相粒子粗大和晶粒粗大,在后续的轧制过程中造成铝板基折弯性能不良,并产生一系列的表面缺陷。为了解决上述问题,本文系统地研究了电解铝液直接铸轧生产过程中出现的表面缺陷,并通过优化退火工艺来提高铝板基的表面质量和折弯性能。本文利用带偏光的金相显微镜(OM)、扫描电子显微镜(SEM)和能谱仪(EDS)等分析方法,以及力学性能、折弯性能测试等手段,系统地研究了黄斑、黑条和色差等表面缺陷的成因和退火工艺对铝板基组织和性能的影响。结果表明,黄斑缺陷的形成原因主要是退火工艺不合理和轧制油理化性能指标不符合要求。在退火加热速度为2.5℃/min、保温时间为6h、加热温度为180℃时,铝板基的黄斑污染程度最轻；基础油为饱和烷烃(二十烷)或者正构烷烃、添加剂为低碳链饱和醇或酯、添加剂加入量为2%时,铝板带的黄斑污染程度最轻。黑条缺陷的形成原因主要是铸轧过程中精炼剂以及由精炼剂包裹的夹杂物进入铝板带坯中,使得铝板带坯表面粗糙度增大,吸附污物及轧制油；或者是铝板带轧制过程中外来杂质被压入板带材表面,造成板带材表面粗糙度增大,吸附污物及轧制油,从而在宏观上表现为黑条缺陷。色差缺陷的形成原因主要是铸轧板坯成分偏析和晶粒粗大。对铝板带进行480℃×4h高温均匀化退火,铝板带第二相粒子细小均匀,铝板带的成分偏析完全消除。随着成品退火温度的升高,铝板基中第二相粒子析出量先增多后减少,在210℃成品退火时铝板基第二相粒子析出量最少,为142931个/mm2；在310℃成品退火时铝板基第二相粒子析出量最多,为178514个/mm2；随着成品退火时间的延长,铝板基中第二相粒子析出量先增多后减少,3h时铝板基第二相粒子析出量最多,为180248个/mm2；16h时铝板基第二相粒子析出量最少,为107576个/mm2。在270℃×4h进行成品退火,铝板基第二相粒子细小均匀,抗拉强度和伸长率分别为135.6MPa和9.2%,折弯处光滑无裂纹,完全满足用户的要求。更多还原

【Abstract】 Aluminum plastic composite panel widely used in curtain wall decoration and advertising signs, because of its good resistance to corrosion, fire prevention, moisture proof and processing properties. Aluminum substrate as an important part of the aluminum plastic composite panel, its quality has a direct effect on the service life of the aluminum plastic composite panel. The traditional production of aluminum substrate is hot-rolled metal ingot remelting and other multi-channel order process, but the production process cumbersome, inefficiency and wasting energy. In recent years, as cast-rolling technology advances, the increasing use of electrolytic aluminum liquid direct cast-rolling in aluminum substrate production with short casting production process is replacing the traditional method. Compared with the traditional method, the production of aluminum substrate by electrolytic aluminum liquid direct cast-rolling has several advantages:short casting production process, low production costs, high production efficiency, etc.However, the direct cast-rolling of electrolytic aluminum liquid still has some technical problems:the temperature of aluminum liquid is too high; the low rate of effective crystal nucleation. The faster cooling rate in cast-rolling causes composition segregation, coarse second phase and the grains. The coarse second phase particles and the grains will cause poor bending and series surface defects of the aluminum substrate. To solve the above problem, this paper systematic studies the cause of surface defects in the direct cast-rolling process of electrolyte aluminum liquid, and improves surface quality and bending properties by optimizing the annealing process.In this paper, polarization optical microscope, scanning electron microscopy and other analysis methods were used and the mechanical properties, the bending properties were also tested to study the cause of macular defects, black bars defects, color defects, and also to investigate the influence of annealing treatment on microstructure and properties of aluminum substrate.The results show that the macular defects mainly due to annealing process unreasonable and the physical and chemical properties of rolling oil does not meet the requirements. When the heating rate is2.5℃/min, the holding time is4h, the heating temperature is180℃, the macular pollution level is the least; when the base oil is saturated hydrocarbons(eicosane) or n-alkanes, the additives is low carbon chain saturated alcohols or esters, the additives addition is2%, the macular pollution level is the least.The black bars mainly due to the refining agent and the inclusions wrapped in the refining agent into the aluminum billet, causing aluminum billet surface roughness increases, adsorbs dirt and rolling oils; or foreign impurities were pressed into the strip surface in the rolling process, resulting the strip surface roughness increases, then the rough places adsorbed dirt and rolling oil, thus presented as black bars at the macro level.The color defects mainly due to composition segregation and coarse grains. When the homogenization annealing temperature is480℃, the holding time is4h, small and uniform second phase particles can be obtained, at the same time, composition segregation are completely eliminated.As the final annealing temperature increases, the amount of second phase particles precipitated in the aluminum substrate increases firstly and then decreases. At210℃the amount of second phase particles precipitated is the least, is142931mm-2; at310℃the amount of second phase particles precipitated is the most, is178514mm-2. As the final annealing holding time increases, the amount of second phase particles precipitated increases firstly and then decreases. At3h the amount of second phase particles precipitated is the most, is180248mm-2; at16h the amount of second phase particles precipitated is the least, is107576mm-2. The second phase particles are small and uniform, the tensile strength is135.6Mpa, the elongation is9.2%, bending properties is optimal when the final annealing temperature is270℃, the holding time is4h、can meet the requirements of users.更多还原