基于实践经验的锌液铝含量预测方法

锌锅中锌液铝含量决定了镀层的结构以及锌锅锌浴行为,热镀锌工艺要求锌液成分稳定控制。利用工业大生产的数据,建立一套铝消耗的经验模型。镀层中的铝含量主要由抑制层厚度决定,抑制层厚度取决于带钢运行速度。镀锌面积决定了锌渣发生量。根据锌锅铝物质平衡,利用已有的生产实绩包括锌锭添加量、镀层带走的铝量以及锌渣发生量等,测算出锌渣铝含量。应用本铝消耗经验模型,可预测锌液铝含量,也为稳定锌液成分的锌锭添加制度做准备。     

连续热镀锌机组锌液温度的精确控制

锌液温度的控制直接影响到连续热镀锌机组锌锅内锌渣的产生量和锌层中抑制层的成分及结构,进而影响热镀锌产品的表面质量。系统分析影响连续热镀锌机组锌液温度精确控制的因素,改进带钢入锌锅温度的控制、锌液温度的检控精度,精确控制锌锅加锌速度,优化锌锅辊预热温度控制,实现锌液温度的精确控制。     

降低锌锭消耗的生产实践

基于锌液与带钢之间的反应机理,通过控制锌液中铝含量及锌液温度、规范锌锅捞渣方法、优化气刀设备与气刀参数等措施,在保证镀层质量的前提下,有效地控制了锌的消耗量.经过阶段性的生产实践,鞍钢天铁镀锌机组的月均锌锭消耗苗较前期降低了 14.8％,取得了良好的经济效益.     

连续热镀锌锌锅内物理场的数值模拟

在带钢连续热镀锌生产中,锌锅中的铝含量及其波动对产品质量有着极其重要的影响,而铝的质量浓度场的分布与锌液在锌锅内的流动、温度分布和锌铝锭的添加位置紧密相关。以某连续热镀锌锌锅为研究对象,采用流体力学方法研究锌铝锭添加对锌锅内流场、温度场和成分场的综合影响。模拟结果表明,自然对流效应改变了锌锅后侧锌液流动形式,冷锌液流向锌锅底部,锌锅后侧形成大范围涡流;锌锅整体温度波动较小,补锭口温度为锌锅最低,锌锅进出口温度较高;B锭(Zn-0.2%Al)融化补充的铝主要进入锌锅底部,高铝锌锭F锭(Zn-10%Al)的添加可调整V形区内的铝溶度分布。此研究为减少锌锅内铝浓度的波动和优化补锭工艺奠定了基础。     

控制带钢连续热镀锌工艺中有效铝的研究及当前技术进展

有效铝是在带钢连续热镀锌涂镀工艺中熔融在锌锅中的总铝中的一部分，在镀层形成的过程中．有效铝可明显地抑制铁锌间的反应。当前通常采用的取锌液样进行化学分析的检验方法是包括未溶解铝份和可能结合到底渣或浮渣的总铝量。本文介绍了在带钢连续热镀锌工艺中控制有效铝的理论研究及相关技术进展。对锌锅内锌液中有效铝的精确测定控制是当前带钢连续热镀锌涂镀工艺中在生产普通热镀锌产品和热镀锌合金化产品时锌锅锌液成分管理的研究的前沿和热点。     

稀土铝添加剂在热浸镀锌中的应用试验

研究了稀土铝添加剂在热镀锌中的应用效果。结果表明当锌浴中加入一定量的镧铈稀土(其含量为0．05％)和铝(其含量为0．10％)，可显著提高热镀锌层光亮性，使锌镀面的耐蚀性提高1倍，锌液粘度降低，锌附着力增强，使镀层减薄32％，减少锌浴表面氧化，锌渣量下降，降低成本，且明显降低热镀锌浴温。     

连续热镀锌生产线中锌层重量的精确控制研究

分析影响锌层重量控制的各种因素,探讨其数学模型;针对邯钢公司冷轧厂热镀锌线的生产实际,提出优化改进措施。生产实践表明,实施措施后,精确控制锌层重量,减少了锌锭消耗。     

热镀锌面板表面质量原因分析

结合冷轧镀锌线宽幅镀锌面板的生产实践,采用SEM、能谱对影响热镀锌面板表面质量的麻点、亮点缺陷形貌及成分进行了分析,对产生机理进行了探讨并提出了相应的改善措施,即提高锌锅铝含量,结果表明:锌锅铝含量提高后,抑制层致密良好,麻点、亮点缺陷比例下降,镀锌面板合格率提高。     

控制锌锭中杂质铁的生产实践

针对锌锭熔铸过程中杂质铁超标问题,研究了锌液温度与铁溶解度的关系,分析了锌锭铁含量较高的原因。在生产中采取相应的措施,使锌锭铁含量得到有效地控制,提高了0~#锌品级率。     

湿法炼锌锌锭品质提升措施探讨

影响锌锭品质的因素包括化学成分和物理外观.某锌冶炼厂针对锌锭品质问题,从锌电解原理及各道工序入手分析镉、铜、铅、铁等化学成分的影响因素及控制措施,从锌锭熔铸过程的各个细节操作控制物理外观质量,采取相应措施后,取得了0#锌产出率100％、废锭率小于1％的效果,最高锌锭品质达到99.997％以上,获得了良好的经济效益.     

焦硫酸钾碱熔在EDTA滴定法测定铝灰渣中铝中的应用

近年来随着铝资源的逐渐紧缺,加紧对铝灰渣中铝资源的回收利用变得日益重要,所以准确测定铝灰渣中铝含量十分重要。由于铝灰渣中铝的存在形态多样而导致样品难以熔解,而且铝灰渣中氟含量高,目前已报道的采用氢氧化钾和氢氧化钠熔解样品后使用EDTA滴定法测定铝时,结果容易偏低。将铝灰渣样品置于铂坩埚中,加入8 g焦硫酸钾试剂,于725 ℃±25 ℃的马弗炉中保温熔融20~25 min至样品熔融完全。由于焦硫酸钾高温熔融样品时冒硫酸烟,从而可以完全驱除样品中F^—。再将样品溶解后加入EDTA,用锌标准滴定溶液滴定过量的EDTA,然后用F^—置换出与铝络合的EDTA,再用锌标准滴定溶液滴定置换出的EDTA,从而得出铝含量。按照实验方法测定两个铝灰渣样品中铝,测定结果的相对标准偏差(RSD,n=9)分别是0.16%和0.34%,加标回收率为98.7%~101%。实验有效解决了铝灰渣样品难以熔解和高含量氟的干扰使得EDTA滴定法测定铝含量时测定结果偏低的问题,适用于成分复杂且铝和氟含量均高的铝灰渣中铝含量测定。     

冲压“积瘤”对汽车外板涂装影响及对策分析

评价热镀锌汽车外板表面质量的参数包括粗糙度、波纹度和PC值,而评价汽车板涂装后表面质量的重点参数包括桔皮、鲜映性、长波、短波等。冷轧钢板表面粗糙度的波长在油漆前后有明显的差别,油漆前冷轧钢板表面的起伏以短波长的比例占优势,而油漆后短波长的部分几乎消失,长波长部分仍然保留并且占优势。以汽车公司反映最为强烈的影响涂装的表面积瘤缺陷为切入点,全面分析了积瘤的类别及缺陷形成的根本原因,重点制定了包括降低入锌锅板温,优化入锌锅板温与锌锅温度的匹配,通过提高锌锅铝含量来抑制锌锅中的铁,保持铁含量在极低的范围内,从根本上抑制锌粒的形成,从而达到有效降低锌粒缺陷比例,降低汽车公司返修率,满足2C1B涂装工艺要求的目的。     

On the wear of a cobalt-based superalloy in zinc baths

Journal bearings made of a cobalt-based superalloy, trade marked STELLITE 6, were evaluated in zinc baths with and without the presence of aluminum and iron. The sleeve and the bushing wore evenly when tested in a pure zinc bath. The surfaces were generally smooth and covered by some rather fine grooves after the test. The wear of the bearings was much more severe when tested in aluminum-containing zinc baths. The worn surfaces of the bearings were fully covered by wide and deep grooves. The coefficient of friction of the superalloy generally increased with increases in the aluminum content of the molten zinc. The iron addition to the molten zinc appeared to affect the friction and wear characteristics of the superalloy. Detailed metallographic and microchemical analyses were performed to elucidate the wear mechanisms. The superalloy was found to react readily with the molten zinc alloys to form intermetallic compounds. In a pure zinc bath, zinc-based intermetallic compounds formed on the bearing surfaces; in baths containing aluminum, a compact intermetallic layer, based on the cobalt-aluminide phase, was detected on the bearing surfaces. Evidence collected in this study indicated that wear debris reacted with aluminum in the molten zinc and transformed itself into hard and abrasive cobalt-aluminide particles. During the test, these particles reattached to the bearing surfaces and built up. Acting as blunt microcutters, these particles plowed the bearing surfaces and created deep grooves. The dominant wear mechanism in the aluminum-containing zinc baths was identified as abrasion; fatigue and corrosive wear, however, served as precursors of the dominant wear mechanism.     

锌锅热平衡测试应用的深入

随着市场对热镀锌产品表面质量要求日益提高,锌锅热平衡的应用也得到了深入,利用两种锌锅热平衡计算方法来确定带钢入锌锅温度,有助于监控锌锅的工作状态。一种方法主要是利用传热学理论公式来计算出锌锅热损失消耗的热量,另一种方法是在锌锅处于备用状态时直接从感应加热器感应线圈电表中的读数得出锌锅的热损失消耗的热量。两种热平衡计算方法都精确地计算了带钢入锌锅温度,完全可以用来验证炉鼻子处板温仪测量结果的正确性。     

铝制品表面条纹偏析的研究

采用带沟槽式的水冷模生产铝合金铸锭,在铸锭表面形成了条纹状成分偏析,并保留在铝制品上,经过碱洗或氧化上色之后,铝制品表面条纹清晰可见,严重地影响了制品的表面质量．本文论述了铝板表面条纹状成分偏析的形成原因及控制措施,这对改善铝制品表面质量有实际意义．     

Structure and mechanical properties of ingots and rolled sections of aluminum alloy based on the Al-Mg-Mn system

Commercial ingots and hot-pressed rolled sections of Al-Mg-Mn alloy doped with zinc, scandium, zirconium, chromium, and vanadium have been studied using optical microscopy, thermal analysis, electron microscopy, and electron-probe microanalysis. The compositions of the phase constituents and aluminum matrix of the alloy are determined. The sensitivity of the alloy to the formation of complex intermetallic compounds during solidification is revealed. The mechanical properties of ingots and rolled sections are determined.     

LBE-LF-CSP低碳铝镇静钢脱氧工艺优化实践

针对邯钢三炼钢厂冶炼CSP低碳铝镇静钢时终点氧质量分数较高,原铝锭脱氧工艺铝吸收率低、进站Als不稳定、综合成本较高等问题,通过深入研究、分析及试验,在转炉工序采用钢砂铝脱氧剂代替铝锭优化出钢脱氧 工艺。经过9号、4号转炉1个月的生产实践,取得了良好的实用效果:转炉出钢脱氧铝吸收率及稳定性明显提高, 精炼工序负担减轻,成品Als控制水平明显提高,综合铝制品成本降低了1.13元/t。     

电感耦合等离子体原子发射光谱法测定铝青铜中7种元素

采用硝酸(1+1)溶解样品,选择Pb 220.353 nm、Sn 189.927 nm、Si 251.611 nm、Zn 206.200 nm、Ni 231.604 nm、Mn 260.568 nm、Fe 259.939作为分析谱线,使用电感耦合等离子体原子发射光谱法(ICP-AES)同时测定了铝青铜中铅、锡、硅、锌、镍、锰、铁。试验探讨了铝青铜中基体元素对待测元素测定的影响,结果表明:通过基体匹配法绘制校准曲线消除了基体效应的影响。各元素的校准曲线线性相关系数均大于0.999;方法中各元素的检出限为0.9～20.8 μg/g。方法应用于铝青铜标准物质中铅、锡、硅、锌、镍、锰、铁的测定,结果的相对标准偏差(RSD,n=10 )在0.36%～4.0%之间,标准物质的测定值与认定值无显著性差异。按照实验方法对两个铝青铜QAl10-3-1.5产品中铅、锡、硅、锌、镍、锰、铁进行测定,加标回收率为90%～108%。     

Prediction of aluminium concentration in molten zinc pot of continuous hot dip galvanising line

Abstract

The strict control of aluminium concentration in a galvanising pot is extremely important to meet the high surface quality of galvanised steels that has been demanded by the industry. The present study proposes a mathematical model for the prediction of aluminium concentration in a galvanising pot of a continuous hot dip galvanising line. It is assumed that aluminium in the molten zinc pot is consumed as coating layer, dross, and inhibition layer. The quantities of aluminium consumed as dross and inhibition layer in the molten zinc pot are evaluated using the results of physical model experiments available in the literature. The operation conditions of the continuous hot dip galvanising line are online collected and then used as input data for the model. It is found that dross is a main source of the preferential consumption of aluminium in the molten zinc pot. The predicted pot aluminium concentration follows the trend of experimentally measured values rather well during both galvanising and galvannealing operations.     

Distribution of aluminum in hot-dip galvanized coatings

Hot-dip galvanized panels of low-carbon (LC) and interstitial-free (IF) steels were produced in a laboratory simulator with an average coating mass of 60 g/m². Three pot aluminum levels were used, viz., 0.10 pct (by wt), 0.15 pct, and 0.18 pct. Metallography, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterize coating and base steel microstructures. Wet chemical analysis and scanning transmission electron microscopy (STEM) were employed for compositional analyses. The aluminum content of the melt was found to be the predominant factor influencing the distribution of Al in the coating. At 0.18 pct melt aluminum, Al is partitioned between the aluminide inhibition layer at the coating-steel interface (∼80 pct) and the zinc overlay (∼20 pct). At 0.15 pct, it is partitioned among the aluminide layer (∼75 pct to 80 pct), zinc-iron (FeZn₁₃, ζ) intermetallic layer (∼5 pct to 15 pct), and the coating overlay (∼10 pct). At 0.10 pct, the aluminum is divided almost equally between the overlay and the zinc-iron intermetallics. At the two lower aluminum levels is the distribution marginally influenced by the steel grade. The ζ was found to not preferentially nucleate at the ferrite grain boundaries. When both the aluminide and ζ occurred at the coating-steel interface, the ζ particles appeared near discontinuities and thinner regions in the aluminide layer. The coating, relative to the melt, is enriched in aluminum because of its concentration in the aluminide and in the zinc-iron intermetallics. This enrichment increases with melt aluminum through an increase in the aluminum content of the aluminide layer and not of its thickness. In addition, a few tens-of-nanometers-thick layer enriched in aluminum, oxygen, and iron is observed on the outer surface of all coatings. The aluminum content in this layer also increases with an increase in the melt aluminum, but it contributes negligibly to the coatings’s content because of its extreme thinness.