铝板带冷轧水基乳化液润滑膜形成特点研究

探讨了不同浓度的水基乳化液形成润滑膜的特点。低速轧制时,随着轧制速度的提高,润滑膜厚度增大。当轧制速度超过临界值时,随着轧制速度的提高,润滑膜厚度降低。考虑速度对乳化液黏度的影响,用4阶多项解函数拟合乳化液黏度随轧制速度变化曲线,对Reynold方程进行修正,使非牛顿流体水基乳化液润滑膜厚度的计算更准确。     

铝板冷轧润滑模型及应用

提出一种建立于流体动力学及塑性变形原理基础上的铝板冷轧润滑模型。可用于预测分析轧制变形区内油膜厚度、前滑、轧制压力及摩擦力分布等。该模型首先求解板材入口速度,然后得到油膜厚度,进行了高粘度矿物油铝板轧制试验,实测了不同压下率下入口油膜厚度,结果表明：实测值与计算值相当吻合,该模型为进一步研究板材冷轧及其润滑过程,优化生产工艺提供了依据。     

冷轧乳化液废水电凝聚处理研究

研究了用电凝聚法处理冷轧乳化液废水的可行性,对比了直流电凝聚与交流电凝聚处理乳化液废水的效果,考查了直流条件下电流密度、电极间距、pH值、电凝聚时间等因素对COD、浊度去除效果的影响。研究结果表明,在相同操作条件下直流电凝聚去除COD、浊度的效果均优于交流电凝聚处理。直流电凝聚在电流密度为30 mA/cm2、电极间距为5 mm、pH值为5、处理时间为45 min条件下,去除COD与浊度的效果均最佳,去除率分别达到9075％和99.76％。     

铜板带冷轧乳化液润滑效果研究

在单因素筛选实验基础上,对硫系油性润滑添加剂(SCO)和磷系极压润滑添加剂(T306)复合使用的配伍效应进行了深入地研究.实验表明,当SCO含量为2%和T306含量为0.6%复合使用时,两者的配伍性能最差,而SCO含量为2%和T306含量为4%复合使用时,两者的配伍性能最好,轧制润滑实验表明,采用优化的乳化液轧制后,铜板带表面质量明显提高.     

冷轧薄板表面色差原因分析

利用共聚焦显微镜对冷轧薄板的色差表面形貌进行观察,发现条状色差主要是由于带钢表面粗糙度不均匀引起。通过生产现场调研发现,在焊缝连接处色差纹路具有连续性特征,且通过轧机急停取样后发现色差主要是由于连轧机的5#机架引起。分析表明,带钢粗糙度不均与轧制过程中乳化液油膜在工作辊面分布不均相关,而油膜不均与乳化液的喷射方式、轧制速度、乳化液的颗粒度和接触角存在直接关系。通过增加乳化液辅助喷嘴,控制轧制速度,并将轧制油的颗粒度由13μm降低至8μm,油滴接触角由80°降低至63°,色差缺陷得到解决。     

道次压下率对冷轧铝板表面形貌的影响

本文通过对干摩擦与滑润轧制后的铝板表面扫描电子显微镜(SEM)观察,研究了不同摩擦条件下道次压下率对冷轧铝板表面形貌的影响。结果表明,道次压下率的增大对表面形貌有着不良的影响。     

乳化液中NH4+含量对钢板表面的影响

马鞍山钢铁股份有限公司的4机架UCM连轧机组对乳化液润滑性能要求很高;而由于漂洗水水质不好,其中高含量的NH4 逐步在乳化液中累积,造成乳化液的高电导率,严重影响了乳化液的润滑性能。通过实验室模拟实验研究得出,调整轧制油的配方能改善乳化液的抗NH4 干扰能力。     

润滑油添加剂对冷轧铝板表面质量的影响

研究了以同一种矿物油为基油,添加脂肪酸、脂肪酸酯和脂肪醇三种油性添加剂时,对冷轧铝板表面粗糙度、光亮度的影响,考察了加入三种添加剂时润滑油的退火性能,对合理地选择添加剂及含量,以提高冷轧板材表面质量是有益的。     

冷轧带钢表面清洁度的研究

通过对影响带钢表面清洁度因素的分析 ,在实际生产中 ,利用改变轧辊的粗糙度、优化乳化液系统等措施 ,改善了轧后带钢表面清洁度。     

防锈铝板表面腐蚀原因分析

采用光学金相、扫描电镜、能量色用谱,俄歇电子能谱和X光电子能谱等多种方法分析了防锈铝板表面发生大面积腐蚀的原因,分析结果说明缝隙腐蚀是导致防锈铝板表面发生失效的主要原因。     

退火温度对1235铝合金冷轧板显微组织的影响

以1235铸轧板(7.0 mm)经过两道次冷轧后的1.1 mm厚的冷轧坯料为对象,借助光学显微镜(OM)、扫描电子显微镜(SEM)及能谱分析仪(EDS)、定量金相分析技术和电解抛光等试验手段,研究了退火温度对1.1 mm厚的1235铝箔坯料组织的影响。结果表明：在相同的退火时间(6 h)内,随退火温度(320~420 ℃)升高,析出相(AlFeSi)数量先增加而后减少且粗化;退火温度为380 ℃时,析出相数量多且均匀细小,平均尺寸约为3 μm。再结晶温度的区间为320~340 ℃;随着退火温度升高,再结晶晶粒逐渐长大;退火温度为380 ℃时,再结晶晶粒数量多且均匀细小,平均尺寸约为23 μm。因此,在380 ℃保温6 h的退火工艺最佳。     

铝和铝合金的大气腐蚀研究现状

综述了铝和铝合金的大气腐蚀特点和大气主要污染组分对铝的大气腐蚀影响. 暴露于大气中的铝表面呈现三层结构, 即氧化铝和氢氧化铝层、其上的腐蚀产物层和最上层的污染物沉积形成的污染物层. 铝的硫酸盐是大气腐蚀层最丰富的腐蚀产物, 其次是铝的氯化物. 着重阐述了SO2, NO2, NO, O3, Cl-和存在的痕量大气有机物对铝的大气腐蚀行为影响.     

Stress corrosion behavior of 6082 aluminum alloy

Stress corrosion tests of 6082 aluminum alloy were carried out by using a three-point bending fixture while holding at 50% of yield strength state through different immersion times in 1.5% NaCl electrolyte solution. The electrochemical impedance spectra and dynamic electric potential polarization curves were measured to indicate the stress corrosion behavior of the alloy. Optical microscopy, scanning electron microscopy, and X-ray energy spectrum analysis were applied for microstructural investigations. The results show that all of the Nyquist electrochemical impedance spectra consisted of high- and low-frequency double capacitive arcs. However, an increase in immersion time while holding at 50% of yield stress resulted in a corresponding increase in the corrosion current density, leading to gradual corrosion depth growth, and a decrease in the corrosion resistance of the alloy. 6082 Aluminum alloy included AlMnFeSi, Mg₂Si, and Si secondary phases. The different secondary phases presented different stress corrosion behaviors. Stress corrosion cracks were generated at the boundaries of AlMnFeSi and matrix or within the AlMnFeSi phase. Crack direction is always perpendicular to the tensile stress applied. Mg₂Si secondary phase was self-corroded as its corrosion potential is lower than that of the matrix. As the electric potential of Si is higher than that of the matrix, corrosion occurred at the matrix side of the boundary between Si and matrix.     

预变形量对2519铝合金抗晶间腐蚀性能的影响

采用硬度测试、扫描电镜与透射电镜研究时效前冷轧预变形量对2519铝合金晶界无沉淀带(PFZ)及第二相大小、分布和抗晶间腐蚀性能的影响。结果表明:经冷轧预变形后,晶间析出相细化并弥散分布,导致各变形量样品的时效硬度均提高,同时使合金到达峰值的时效时间缩短;且随着预变形量的增加,合金晶间腐蚀性能由4级降至0级,抗晶间腐蚀能力增强。这是由于晶界无沉淀带变窄,同时在晶界析出的平衡相由链条状分布逐渐变为不连续分布,使连续网状的腐蚀通道转变为断续的腐蚀点,进而提高了2519合金的抗晶间腐蚀性能。     

船舶用耐蚀铝合金的研究进展

介绍船舶耐蚀铝合金的应用概况,讨论了船舶用耐蚀铝合金的耐蚀性能,对船舶用耐蚀铝合金的发展方向进行了展望。     

Accelerated corrosion test and corrosion failure distribution model of aircraft structural aluminum alloy

Based on corrosion damage data of 1 0 years for a type of aircraft aluminum alloy, the statistical analysis was conducted by Gumbel, Normal and two parameters Weibull distribution function. The results show that aluminum alloy structural member has the corrosion history of pitting corrosion--intergranular corrosion-exfoliation corrosion, and the maximum corrosion depth is in conformity to normal distribution. The accelerated corrosion test was carried out with the complied equivalent airport accelerated environment spectrum. The corrosion damage failure modes of aluminum alloy structural member indicate that the period of validity of the former protective coating is about 2.5 to 3 years, and that of the novel protective coating is about 4.0 to 4.5 years. The corrosion kinetics law of aluminum spar flange was established by fitting corrosion damage test data. The law indicates two apparent corrosion stages of high strength aluminum alloy section material： pitting corrosion and intergranular corrosion/exfoliation corrosion. The test results agree with the statistical fit result of corrosion data collected from corrosion member in service. The fractional error is 5.8% at the same calendar year. The accelerated corrosion test validates the corrosion kinetics law of aircraft aluminum alloy in service.     

Improved corrosion protection of aluminum alloys by electrodeposited silanes

Organofunctional silanes recently have emerged as outstanding, environmentally friendly corrosion protectors for metal substrates, compared with conventional chromate treatments. A simple immersion technique is typically used to coat the metal surface with silane films. However, the thickness and uniformity of the films are uncontrolled in this process. This paper proposes a new deposition technique for the silane films on the metal surface, i.e., by electrodeposition. Hydrolyzed silanes are water-soluble, ionized molecules, so they can be deposited on metals by electrodeposition. Various combinations of silane mixtures were tested at different voltages, pH values, bath concentrations, and exposure times on panels of alloy aluminum and mirror-polished ferro-plate. The surface structure was characterized by scanning electron microscopy (SEM) and ellipsometry. The resistance of the film to corrosion was investigated by direct current (DC) polarization and electrochemical impedance spectroscopy (EIS) techniques. Electrodeposition results in a more organized and uniform film with fewer pores, compared with immersed or dipped films. This paper was presented at the 2nd International Surface Engineering Congress sponsored by ASM International, on September 15–17, 2003, in Indianapolis, Indiana, and appears on pp. 320–26 of the Proceedings.     

Effects of environmental factors on corrosion behavior of aluminum

Aluminum, used as a material for heat exchangers in air conditioners, often has problems of leakage of refrigerant on the Al surface due to corrosion. The problems originate from pitting corrosion of the Al in an external environment. To understand corrosion problems, it is necessary to study the corrosion behavior of Al in various environments. In this study, the effects of environmental factors on the corrosion behavior of Al were studied by the surface analysis and electrochemical testing in 3.5 wt% NaCl solutions, with changes of dissolved oxygen, temperature, and concentration of Cl⁻ and S ions. Among the external environmental factors, the presence of oxygen and the increase of Cl⁻ ion concentration do not significantly affect the corrosion potential of Al, leading to an increase of only 1.1 and 6 times, respectively. There was a significant decrease in the corrosion resistance of Al, approximately 40 and 800 times, respectively, with the increase of concentration of S and temperature.