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。     

热浸镀锌锌锅中锌液流动的数值模拟

根据包钢薄板厂热镀锌锅的结构和操作工艺参数,采用Fluent软件,建立了热镀锌锅的三维模型,在不考虑锌锅锅壁与锅底的厚度和炉鼻以及气刀对锌液流动影响的情况下,对热镀锌锅内锌液的流动进行了计算。模拟结果表明：钢带拉速是锌液运动的主动力,宏观上锌液的速度正比于钢带拉速;钢带宽度影响着锌锅内漩涡的大小和位置,进而影响着锌液的整体流动状态;感应加热器的功率变化只对其附近区域锌液的流动有影响。     

环境用锌铝镁退火炉锌鼻子的优化设计

从无缺陷镀锌锌鼻子设计入手,对比阐述了环境用锌铝镁锌鼻子的设计要点,并得出结论：锌铝镁机组锌鼻子不需要设计伸缩膨胀节,锌鼻子内部采用两台锌液泵的鼓抽方式,强化流动排渣,锌蒸汽采用高温保护气体携带外排的方式是应对锌鼻子的锌蒸汽的有效手段。     

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。     

热镀锌锅中感应加热器功率和位置对锌渣分布的影响

锌渣会导致锌液流动性变差,严重影响镀锌板的表面质量,给公司带来经济和名誉损失,探究带钢热镀锌过程中锌渣产生的规律,能够减少其对产品质量的负面影响。基于FLUENT仿真软件,研究了热镀锌锅中感应加热器功率和位置对锌渣分布的影响,结果表明,感应加热器功率和位置的变化对锌渣生成量的影响有限;随着感应加热器的功率变化,底渣和浮渣在锌液中的分布没有出现较大变化;当加热器位置距离锌液液面较近时,底渣高度会明显增高;当加热器位置距离锌液液面较远时,带钢进出入锌锅处会堆积大量浮渣。因此,加热器的位置不宜过高和过低,应取适中位置。     

简便快速地测定分析双层锌锅内锅有否漏锌的方法

简便快速地测定分析双层锌锅内锅有否漏锌的方法东台市钢丝绳厂吴尚涛１引言双层锌锅内锅内壁徐防蚀涂料有明显提高锌锅寿命，减少锌渣等优点，在热镀锌行业已被越来越多的人所认识，并得到了普遍应用。鉴于双层锌锅在用到一定的时间后，如果内锅有锌渗漏到夹层中，由于锌...     

工业生产条件下连续热镀锌锅中锌渣扩散的数值模拟

基于欧拉-拉格朗日方法的离散相模型,针对锌液体外循环系统下连续热镀锌锅中三种不同类型的锌渣,利用数值模拟的方法计算锌锅中锌渣的浓度差分布.分析锌渣扩散得到了锌渣在带钢表面及锌锅中的运动轨迹和分布规律.结果表明:锌渣在带钢上的沉积率随着锌渣粒度的减小而升高;由于锌渣密度的差异,当锌渣直径小于80μm时,沉积率从高到低依次为悬浮渣、面渣和底渣.面渣在带钢出口后侧区域的平均停留时间最长,在该位置设置抽锌管将有利于面渣的去除;在V形区内侧区域带钢上的悬浮渣质量浓度最高,对带钢影响最大;底渣主要运动区域为锌锅底部,基本不会黏附于带钢表面,对带钢质量影响最小.      

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。     

热镀铝锌厚板锌渣缺陷原因分析

锌渣缺陷一直是困扰热镀铝锌厚板生产表面质量控制的难题。锌渣缺陷的宏观形貌呈片状,对其进行微观形貌及能谱分析,结果表明：片状锌渣为锌灰导致,而非常规认知的锌锅内的浮渣和辊系结渣引起。通过对片状锌渣缺陷产生原因的分析,并结合梅钢热镀铝锌产线的工艺特点,提出了片状锌渣缺陷的控制措施。     

连续热镀锌工艺中锌锅内锌液温度分析

连续热镀锌工艺中锌液温度是一个主要的技术参数,它的高低直接影响生产质量的好坏.采用现场实验与热平衡计算相结合的研究方式,研究感应锌锅的热支出与热收入,系统分析感应器混频加热、带钢入锅温度等因素对锌锅内锌液温度的影响,为最佳浸镀时间的确定提供基顾数据,对提高镀锌板的质量具有一定的意义与价值.     

Simulation of special flow affecting dross formation on steel strip in galvanising bath

The zinc flow in a galvanising bath is numerically simulated for three cases, and the flow field is analysed using three-dimensional views. It is found that the flow near the zinc surface directs from the strip to the ingot side when inductors are equipped and whether ingots are melting or not, and the flow direction is opposite to that near the zinc surface for the case without inductor and ingot, which does not exist during the bath operation process. Whirlpools are found to be formed between the snout and the bath side walls, which will increase the chance of dross particles touching the strip surface. Some effective measures are proposed to stop more dross from adhering to strip. This work will lay foundation for the optimisation of the galvanising process to improve the coating quality of steel strip.     

Influence of air knives on liquid zinc flow in galvanising bath

Liquid zinc flow in a galvanising bath was numerically modelled for four cases, and flow field using three-dimensional views was analysed. Flow pattern analysis shows that there are two vortexes (circulations) close to the zinc flow surface and another two below them, which are attributed to strip movement and two guide rolls. Jets from air knives will generate high pressure and zinc backflow. Based on the results of the jets study, the impact of air knives on zinc flow in a galvanising bath was studied on the lengthwise and widthwise section views. It was found that high pressure and zinc backflow due to jets from air knives have little influence on the flow patterns far away from the strip outlet. It was also found that zinc backflow has little influence on the zinc flow surface far away from the strip outlet, while high pressure and zinc backflow together have some influence, that is, the jets of air knives can effectively influence the zinc flow around the strip outlet. This work lays the foundation for the optimisation of the galvanising process to improve the coating quality of steel strips.     

热镀锌液中锌渣的电磁分离

 锌液中的锌渣是影响热镀锌钢板表面质量的重要因素。从电磁净化理论分析和电磁分离实验研究两个角度出发,对解决热镀锌液中锌渣的去除进行了探讨。结果表明,在磁场频率175 kHz、磁感应强度均方根值005 T时,电磁作用10 s,可有效去除粒度大于10 μm的锌渣;通过对锌液的连续净化处理,粒度小于15 μm的锌渣去除效率可达到825%。     

Microstructural study of galvanized coatings formed in pure as well as commercial grade zinc baths

This investigation is an effort to have a better understanding of the growth kinetics and morphology of the coating formed during the galvanizing process in pure as well as commercial grade zinc baths. The protective coating that is formed during hot dip galvanizing, normally between 450 and 480°C, consists of a series of Fe-Zn intermetallic layers, which have been identified as gamma (Γ), delta (δ), zeta (ξ) and an outer eta (η) layer, highly rich in zinc. There is apparently no delay in the formation of ξ or δ phases in both pure as well as the commercial grade zinc baths. The gamma (Γ) phase is formed after an incubation time of about 30 s at a bath temperature of 470°C in the pure zinc bath. Its formation is further delayed in the commercial grade zinc bath. The last morphological feature is the formation of a second ξ layer at the ξ/δ interface in the pure zinc bath. In the commercial grade zinc bath two different morphologies of ξ phase are seen starting from the lowest dipping time, and also the overall coating is considerably thicker due to formation of several iron-zinc intermetallics which degrade its ductility and outward appearance. Commercial grade zinc also enhances the dross formation in the bath and deteriorates the quality of the coating. Presence of transverse cracks as well as entrapment of dross particles in the coating is attributed to the less compact coating that is formed in the commercial grade zinc bath.     

锌浮渣处理的研究与实践

阐述了锌浮渣干法和湿法处理的工艺流程,比较了两种方法的优缺点,从试验角度探索锌浮渣处理后的综合利用,以减少中间资金占用,增加企业经济和社会效益.     

热镀锌钢带沉没辊辊印缺陷成因分析及控制方法

沉没辊辊印缺陷属于镀层缺陷,产生因素很多,结合武钢生产经验,以及对生产中产生缺陷的检测分析,对该缺陷的成因进行探讨,提出控制缺陷的方法,主要包括:控制带钢入锌液板温、优化稳定锌液成分、改进沉没辊沟槽形貌等。     

Separation behaviour of zinc dross from hot dip galvanising melts of different aluminium concentrations by alternating magnetic field

Abstract

Dross in zinc pots is the most important factor that impairs the surface quality of hot dip galvanising automobile steel sheet. Separation behaviour of zinc dross from galvanising melts of different Al concentrations (0·12, 4·5 and 55·0 wt-% by an alternating magnetic field has been investigated in order to reduce the dross defects on steel sheets. The properties of different zinc drosses were investigated by means of EDAX and the quantitative metallographic method and the conductivities were measured by physics property measurements system. The experimental results show that the zinc dross in different hot dip galvanising melts has different morphologies, compositions and structures, and the average particle size of the dross increases with the Al concentration. In the case of extra iron (above the solubility limit) in the zinc melt, zinc dross quantity also increases with the Al concentration. All of the three types of zinc dross particles >5 μm can be successfully separated when the magnetic frequency is 17·5 kHz, effective magnetic flux intensity is 0·05 T, imposed time is 15 s and the cross-section of the ceramic square pipe is 5 × 5 mm.     

综合利用锌浮渣制备超细活性氧化锌的扩大试验研究

研究用硫酸浸出锌浮渣制备超细活性氧化锌粉体的扩大试验。试验结果表明：小试提供的工艺条件是可行的；在小试的基础上，扩大试验提高锌溶液的浓度和沉淀剂的浓度．以减小回收硫酸铵的难度；超声波辐射时间不少于30min．微波煅烧时间也不少于12min。采用日本岛津产EPMA-1600型电子探针对产物的微观结构、粒度和形态进行表征。结果表明：超细活性氧化锌的形貌为球形．且分散均匀，粒度均匀，其平均粒径为100nm．比表面积为41m^2／g。     

铅锌混合矿氧气熔融脱硫

随着烧结+鼓风炉工艺处理铅锌混合精矿能耗高和环境污染的问题日益凸显,使用熔池熔炼法替代烧结工艺成为铅锌混合精矿较好的火法冶炼工艺选择。采用静态法和XRD技术研究了O₂流量、温度、入炉炉料成分对铅锌混合矿脱硫的影响以及脱硫渣物相变化。结果表明:与烧结工艺相比,铅锌混合精矿高温熔融脱硫时间短、脱硫率高。O₂流量的增加和温度的提高有利于铅锌混合矿脱硫反应的进行,铅锌混合矿脱硫率随着ω（Fe）/ω（SiO₂）和ω（CaO）/ω（SiO₂）的增加而降低,但在1 400 ℃时ω（CaO）/>ω（SiO₂）的增加有利于脱硫速率的加快和脱硫率的增加。当反应温度为1 250 ℃时,随着熔渣中Fe/SiO₂的增加,熔渣中尖晶石相（Zn_xFe_3-xO_4+y）开始形成并增多。