热浸镀铝工艺及镀层分析

在实验室条件下通过多次实验研究了采用熔剂法进行纯铁表面热浸镀铝的工艺及低真空处理方法，摸索出较为合理的工艺流程及筛选出合适的助镀剂和镀铝液表面熔剂，并简要分析了原因．对影响镀层的几个工艺参数，如浸镀时间、温度等进行分析讨论，利用扫描电镜对其镀层进行成分和结构分析．同时，对经过低真空处理的试样和没有处理的试样做了成分对比分析．     

稀土镧对热浸镀铝层耐蚀性的影响

通过CO2和H2S腐蚀试验，采用SEM和EDS研究了20钢经热浸镀稀土(镧)铝和扩散处理后的渗层组织和耐蚀性能。结果表明：镧对铝的扩散具有促进作用，改善了镀层的耐蚀性能；当铝中加入镧的含量达到0.5%时，其耐蚀性最好。     

Influence of Oxide Morphologies on Galvanizability of Third Generation Automotive Steel

Focusing on improving the galvanizability of the third generation automotive steel, the effect of surface ox ide morphologies on the galvanizability was studied. The results show that the surface oxide types of sample steels by X ray photoelectron spectroscopy （XPS） analysis after annealing in different conditions are the same. Only MnO, MnO2 and Cr2O3 were detected and no complex oxide exists on the surface. Morphologies of surface oxides can greatly influence the galvanizability of the third generation automotive steel. Nodule-like oxide surface can contribute to better wettability and inhibition layer than vitreous film like oxide surface. Galvanized panels of nodule-like oxide surface steels only show pinhole sized bare spots, while panels galvanized from vitreous film-like oxide surface steels reveal larger areas of bare spots and uncoated areas. Inhibition layer observed in galvanized panels of nodule-like oxide surface steels is compact but not homogeneous; some inhibition layer grains are fine, and others are coarse, while the inhibition layer grains of panels galvanized from vitreous film-like oxide surface steels have a non-compact morphology with some particularly fine equiaxed crystals which developed deficiently.     

热镀锌生产线中浴装机器气刀精度调整的研究

热镀锌生产线中浴装机器（ YG设备）的气刀装置精度是决定镀锌工序的关键因素，对整个镀锌板材产品质量具有重要意义。本文研究了气刀装置精度调整的方法，通过解体控制优化、气刀喷嘴开口度优化、气刀平行度控制优化以及气刀升降位置优化，使镀锌板上气刀痕迹显著减少，从而提高镀锌板产品的质量。     

攀钢镀锌机组连续退火炉在线控制系统

针对攀钢现有的自动化控制模式,开发出一种在线优化二级控制系统（L2）。介绍了L2系统的组成及其功能。系统在线投入后运行稳定,各项生产技术指标得到了系统的优化,极大地减少了生产过程中生产参数的人工输入。     

Laboratory hot-dip aluminizing of sheet steels

It is a matter of common knowledge that in laboratory hot-dip aluminizing, great difficulties are often encountered in preparing specimens that are free of surface oxides and other ubiquitous contaminants such as oils, grease and dust. Inadequate preparation of specimens will inevitably lead to the prevention of alloy layer growth during hot dipping and poor coatings following withdrawal. This paper describes a method for the production on a laboratory scale of hot-dipped type 1 aluminized sheet- steel specimens of commercial quality.     

邯钢光伏支架用热镀锌S390GD(S450GD)+Z产品的开发

环保节能领域光伏支架用有锌花镀锌产品是邯钢市场开发的重点,但用户对其表面质量、力学性能、耐蚀性能和变形延展性有较高的要求。从热轧备料,酸洗工艺,热镀锌退火温度及锌层控制等方面阐述了开发光伏支架用热镀锌S390GD(S450GD)+Z产品的质量保证措施。通过降C、增Mn的化学成分设计,板坯出炉温度1 100～1 150℃、粗轧压下率40%～45%、终轧温度(850±20)℃、卷取温度降至(580±20)℃ 的热轧工艺优化,保证了热轧原料强度。通过酸液温度、酸洗速度、缓蚀剂添加量的优化,以及热镀锌退火温度、锌液成分的优化改进,实现了锌花结晶均匀性控制,产品质量满足用户要求。     

预镀镍层对一种C-Mn-Si高强钢选择性氧化行为的影响

目的 抑制高强钢中合金元素在表面选择性氧化.方法 在一种C-Mn-Si体系高强钢表面预先电镀100 nm厚度的镍,然后在镀锌模拟器上进行模拟退火处理.使用扫描电镜及其附属的X射线能谱仪观察分析了试样表面形貌和元素构成,使用辉光放电光谱仪研究了样品退火后表面的元素深度分布,使用X射线光电子能谱鉴定了样品退火后的表面化合物种类.结果 预镀镍样品退火后,表面存在一层疏松的镍层,少量颗粒状氧化物分布在镍层表面;而未镀镍样品退火后,则在表面晶界和晶粒中均出现颗粒分布的氧化物.延长退火时间会显著增加表面氧化物的数量,降低表面镍含量.辉光放电光谱分析表明,表面沉积的镍镀层能够抑制合金元素在表面的选择性氧化.退火10 s后,Mn元素的表面富集量减少了52％,Si元素的表面富集量减少了23％;而退火50 s后,Mn元素和Si元素的表面富集量均减少42％.X射线光电子能谱分析表明,镀镍样品表面的氧化物以不定型氧化物为主,而未镀镍样品表面的氧化物主要为晶态氧化物.结论 100 nm 厚度的预镀镍能够有效降低Si 和Mn 向外的扩散速率,抑制Si 和Mn 元素在表面的富集程度,改变表面选择性氧化产物的种类,减少高强钢表面氧化物的数量.     

稀土Y对热浸镀铝镀层组织及耐蚀性的影响

目的 研究稀土Y对热浸镀铝层的影响,提高热浸镀铝件的耐蚀性能.方法 通过向热浸镀铝液中添加不同量的铝钇合金,获得稀土Y含量不同的热浸镀铝件.选用3.5％的NaCl溶液为腐蚀溶液,利用SEM、EDS观测其形貌、成分,并使用电化学测试和全浸试验研究稀土Y对镀层耐蚀性能的影响.结果 当添加0.2％Y时,热浸镀铝层表面平整、无孔洞,针状相细小,镀铝层减薄,过渡层由锯齿状转变为连续带状.稀土Y的添加使镀铝件的自腐蚀电位正移,自腐蚀电流密度减小,添加量为0.2％时,自腐蚀电位最正,为?0.7857 V,自腐蚀电流密度最小,为1.3505×10?8 A/cm2.与添加其他稀土元素相比,添加0.2％Y时,镀层的破裂电位Eb最正,为?0.6957 V.不同稀土含量的热浸镀铝件的交流阻抗谱都为单一的容抗弧,当稀土Y添加量为0.2％时,容抗弧半径最大.全浸试验中,添加0.2％Y的镀件的腐蚀速率最低.结论 稀土Y的添加可以使热浸铝层光滑、连续,且具有提高其耐腐蚀性的作用.Y添加量为0.2％时,镀铝件的耐蚀性最好.     

Studies on the potential risk of liquid metal assisted cracking (LMAC) in normal‐temperature and high‐temperature hot‐dip galvanizing of high strength bolts of dimensions greater M24

Liquid metal assisted cracking (LMAC) mainly occurs due to an unfavorable interaction of three factors: a susceptible material condition, presence of a liquid metal and sufficient tensile stress. Hot‐dip galvanizing of high‐strength bolts induces high thermal loads in bolts made of tempered steel in the presence of a zinc melt and thus, provides the boundary conditions for the above mentioned critical factors to interact. The focus of this study is on investigating thermally‐induced stresses in large diameter bolts and their impact on the formation of liquid metal assisted cracking (LMAC). In order to calculate the thermal loads in hot‐dip galvanizing, simulations were carried out regarding the thermo‐mechanical behavior of bolts during the hot‐dip galvanizing process. The simulations illustrate that cracks are most likely to occur in the first thread turn. This prediction is confirmed by experimental observations.