电镀锌钢板的黑变机理

在发现铅是导致电镀锌钢板黑变发生的关键因素的基础上 ,对电镀锌钢板的黑变机理提出了锌铅共沉积假说和硫酸铅胶体膜假说 ;并对不同工艺中获得的电镀锌钢板进行了黑变培养 ,通过丁达尔和界面电泳实验研究了铅在硫酸锌溶液中的存在形式 ,通过钝化及破胶实验研究了钝化工艺和镀后清洗对黑变的影响 ,验证了黑变是由于硫酸铅胶体膜在镀锌层外表面被吸附而造成的。     

铅与光照对镀锌层黑变的影响

在硫酸盐镀液中所得的含铅与不含铅的镀锌试片，经铬酸盐钝化后，通过湿热试验（ＨＣＴ）进行了黑变培养，采用试片的表面明度差来表征黑变的程度，考察了铅和光照对其黑变速率的影响，发现镀液中铅离子的存在使黑变反应的活化能Ｅａ从３４ｋＪ／ｍｏｌ左右降低到２１ｋＪ／ｍｏｌ左右，从而加速了黑变反应。光照虽然使Ｅａ降低了０．５ｋＪ／ｍｏｌ，但同时较大幅度地降低了指前因子Ａ的值，总的作用结果是抑制了黑变的反应     

镀锌系钢板表面处理新工艺

简述镀锌系钢板的低铬酸盐溶液处理及丹宁酸溶液处理新工艺,并讨论了镀锌系钢板经这些新工艺处理后的耐腐蚀性能和涂装性能。     

电镀锌层表面黑变膜的研究

用ＳＥＭ、ＥＤＸ、ＸＲＤ、ＸＰＳ等技术分析了电镀锌层表面黑变膜的组成和结构。结果表明,黑变膜是锌的腐蚀作用及杂质Ｐｂ去极化作用的共同产物。它由ＺｎＯ、Ｚｎ５（ＣＯ３）２（ＯＨ）６及微量ＰｂＯ组成,膜表层Ｚｎ是以ＺｎＯ形态存在,而膜内层则以非化学计量化合物ＺｎＯ１－ｘ形态存在。并发现黑变膜是一种锌受腐蚀所形成的表面膜上产生的光干涉现象。     

热镀锌钢管表面黑变形成机理研究及解决方案探讨

研究了镀锌钢管表面黑变的机理及成因;通过中性盐雾试验和高温高湿试验,探讨了钢管表面黑变的解决方案.结果显示,钢管表面黑变成因与表面锌层中铅元素的含量及分布直接相关.铅含量较高区域腐蚀电位较高,铅含量偏低区域腐蚀电位相对较低.当有腐蚀介质存在时,会发生电化学腐蚀,使电位较低区域加快腐蚀,从而导致该区域腐蚀产物富集,氧元素...     

钢板电镀锌表面聚苯胺膜硅烷改性的研究

在加入硅烷偶联剂γ-APS的苯胺中性溶液中采用恒电流法在电镀锌钢板上制备聚苯胺膜,采用SEM观测其表面形貌,测试不同条件下聚合膜的厚度.交流阻抗和盐雾实验表明,加入γ-APS后,聚苯胺膜层的致密性和防护性明显提高,接近铬酸盐钝化膜.通过XPS分析,得到γ-APS改性聚苯胺膜掺杂度为11%、氧化度为64%;与改性前聚苯胺膜相比较,掺杂度降低、氧化度增高.结合红外光谱和XPS分析,发现聚苯胺膜中存在4种化学环境:C-Si-O-Si,C-Si-OH,C-Si-O-C,C-Si-O-Zn.     

明度差法研究电镀锌铬酸盐钝化膜的耐蚀性

用明度差法研究了电镀锌未钝化及涂覆型钝化试片在湿热实验中的初期腐蚀行为。通过考察明度差△Ｌ随时间及温度的变化关系，发现未钝化镀锌层的初期腐蚀规律符合对数方程，而钝化后的符合Ｗａｇｎｅｒ方程，即印化膜的存在改变了腐蚀的历程，使钝化膜内锌离子的外护散或膜外氧的内扩散成为腐蚀的控制步骤，有效地提高了镀锌层的耐蚀性，采用明度差法可以反映电镀锌钢板腐蚀的程度。     

电镀锌钢板涂敷型低铬钝化研究

应用正交试验优选电镀钢板－ＣｒＯ３－Ｈ３ＰＯ４－ＳｉＯ２系钝化剂配方,研究钝化注ｐＨ值,钝化时间,干燥温度对钝化膜耐蚀性的影响,提出一种涂敷型低铬钝化新工艺。该工艺所得钝化膜稳定性好,其抗白锈能力是目前国产涂敷型铬酸盐处理镀锌钢板的３倍。文中还对ＣｒＯ３－Ｈ３ＰＯ４－ＳｉＯ２系钝化膜的形成机理和防护机制进行了初步探讨。     

镀锌钢板表面新型环保钝化膜的抗腐蚀性能研究

对采用不同表面处理的镀锌钢板进行微观组织、化学成分、电化学性能和腐蚀性能测试,分析了不同钢板的耐腐蚀机理。结果表明,镀锌钢板表面新型环保钝化膜表现出优异的耐腐蚀性能,其中所加入的封孔剂弥补了三价铬钝化不足的缺陷,提高了其耐腐蚀性能。     

电镀锌板表面斑状缺陷形成机理分析

采用扫描电镜对电镀锌板表面一类斑状缺陷从微观组织及成分等角度进行了分析,对其形成机理进行了探讨。结果表明:电镀锌板表面缺陷呈被局部碾压形貌,且缺陷部位粘附大量小黑点,小黑点的微区成分主要由C、O、Mg、S、Ca、Si、Mn等组成。通过产线排查及特征元素追溯发现缺陷来自于连续退火基板,导致缺陷产生的根本原因是富集在连续退火线水淬槽及与其相连水管内壁的水垢类异物粘附在板面上。通过清理连续退火线水淬槽及相连水管内壁后,基板表面质量得到控制,缺陷得以消除。     

Research of silane film cooperation with ZrO2 on electrogalvanized steel

The silane composite film formed on electrogalvanized steel sheet by silane film with ZrO2 improve the corrosion resistance.The surface morphology,the structure and composition as well as the corrosion resistance of the prepared silane composite film were investigated by SEM,AFM,XPS and electrochemical test.The experimental results showed that the structure of the silane composite film was composed of Si-O-Si three-dimensional network doped with ZrO2 showing excellent corrosion resistance,because the structure of this kind of composite film has much less micropore which improves the uniform and density of the silane film.improves the uniform and density of the silane film.     

高润滑皮膜钢板的成形特性及在汽车覆盖件中的应用

高润滑皮膜钢板通过固化手段在合金化熔融镀锌钢板(GA钢板)表面的GA层形成固态润滑皮膜,紧密附着在钢板表面,从而降低钢板的表面摩擦系数,改善润滑性能,达到提高钢板成形性、削减原材料成本的目的。本研究采取适当方法对高润滑皮膜钢板和普通GA钢板的滑动性能、拉伸性能以及胀形性能进行了对比试验,并提出以成形余裕度作为成形性的评价参数,结合在实际汽车覆盖件生产中的成形余裕度测试。结果表明:高润滑皮膜钢板的各项性能对比普通GA钢板均有较大地提高;在成形稳定性方面,对比普通GA钢板提升了60%以上。目前,高润滑皮膜钢板已经在丰田、本田等汽车制造厂中被广泛使用。     

X70管线钢点蚀行为研究

对X70管线钢的凹坑进行了SEM观察,并对控轧控冷工艺以及层流冷却水进行了分析研究。实验结果表明,X70管线钢凹坑是由于点蚀腐蚀所引起,而点蚀产生的原因是由于层流冷却水中的氯离子浓度偏高。另外,对X70管线钢的点蚀形成机理进行了讨论。     

Microstructures and magnetic properties of heatproof domain-refined grain-oriented silicon steel sheets

Microstructures and magnetic properties of heatproof domain- refined grain- oriented silicon steel sheets were studied. Local strains were introduced using two types of gear roll as well as cog tips, one 35 Μm and the other 85 Μm. After the local strains were introduced onto sheets, the distribution of hardness near the groove was measured. The nuclei of micrograins were investigated at various applied rolling loads. After stress-relief annealing, various shapes of microgranes and grooves were observed. The effect of these various shapes of grooves and micrograins on magnetic properties was clarified. The role of micrograins and grooves on domain refining is discussed.     

Effects of plating factors on morphology and appearance of electrogalvanized steel sheets

Because the lightness, the gloss and the press-formability of electrogalvanized steel sheets change depending on the morphology of deposited Zn, control of this factor is essential to improving these properties. The effects of plating factors on the morphology of deposited Zn were systematically discussed both from the crystallographic viewpoint of epitaxy between Zn and steel and from the electrochemical viewpoint of the overpotential for Zn deposition. Plating factors include crystal orientation of steel substrate, current density, flow rate, temperature, addition of inorganic compounds to the solution and pre-adsorption of organic compounds. These plating factors affect the overpotential for Zn deposition and epitaxy between Zn and steel. The crystal orientation index of the Zn basal plane and the platelet crystal size of Zn are decreased with increasing the overpotential for Zn deposition. They are also decreased with decreasing the epitaxy between Zn and steel, even when the overpotential is kept constant. When the overpotential for Zn deposition is increased, the surface roughness of deposited Zn increases because of an increase in the inclination of the Zn basal plane to the steel substrate. When the epitaxy between Zn and steel is decreased without changing the overpotential, the surface roughness is reduced due to the decrease in platelet crystal size of Zn, although the inclination of the Zn basal plane is somewhat increased. The lightness of deposited Zn is enhanced with decreasing the surface roughness of Zn.     

Self-pierce riveting of multiple steel and aluminium alloy sheets

Multiple steel and aluminium alloy sheets were joined by self-pierce riveting. Self-pierce riveting is attractive for joining multiple and dissimilar sheets, because joining of individual interfaces is not necessary unlike the conventional joining processes, i.e. sheets except for a lower sheet are merely pieced with a rivet shirt. The steel sheets ranged from mild steel to ultra-high strength one having 980 MPa in tensile strength, and the joinability for three steel and aluminium alloy sheets for various combinations was examined from both experiments and finite element simulation. The joinability was improved by setting a softer sheet uppermost due to smooth piercing. In addition, the joining range for self-piece riveting of three high strength steel and aluminium alloy sheets was extended by optimising a shape of the die, and the ultra-high strength steel, mild steel and aluminium alloy sheets were successfully joined.     

退火温度对低碳铝镇静钢板组织及力学性能的影响

通过拉伸试验检测了单机架可逆轧制冷轧压下率为68％低碳铝镇静钢板力学性能,用金相显微镜观察试验钢板冷轧态与退火态的纤维组织,并用X射线衍射仪测量试验钢中不同类型织构的含量.结果表明,退火温度由660℃升高至720℃,低碳铝镇静钢的屈服强度为201 ～212 MPa,抗拉强度为278 ～311MPa,屈强比为0.68 ～0.72,总伸长率为38％ ～ 42％,加工硬化指数n值为0.21-0.24,而塑性应变比r值为1.25 ～1.58,|△r|值为0.39 ～0.78.退火温度的升高使得再结晶后晶粒尺寸增加和“饼型”程度加大,γ纤维织构强度增加.当退火温度升高至720℃时,再结晶晶粒尺寸不均匀,|△r|值较大,且抗拉强度明显降低.综合作用的结果是,退火温度在680 ～700℃范围时较为合适,深冲性能较好.