表面预处理及镀后处理对连续热浸镀铝组织和性能的影响

发布时间：2018-04-25 03:25

  本文选题：热浸镀铝 + 预镀工艺　； 参考：《西安建筑科技大学》2017年硕士论文

【摘要】：本文利用鞍钢连续热镀锌模拟器,主要研究了镀前预电镀Fe/Ni工艺以及镀后过时效处理工艺对美钢联法连续热浸镀纯铝/铝硅镀层组织结构和力学性能的影响以及各工艺在实际生产中应用的可行性。同时采用多种模型对镀层形成过程中的Fe-Al金属间化合物的热力学性质与动力学性质进行了计算与分析,进一步明确镀层的形成机理。最后通过ANSYS Workbench软件对镀层进行了三点弯曲试验的有限元模拟计算,分析了镀层的开裂形式以及力学加工性能的影响因素。研究结果表明:合金层形成过程中只可能同时存在Fe2Al5相与FeAl3相,Fe2Al5相首先在固液界面形核并长大并形成单相层,随后FeAl3相才会在Fe2Al5相与铝液界面形核。镀后冷却速度越快合金层厚度越薄,当冷却速度超过一定程度后减薄同样的厚度所需的冷却能力将会成倍增加,理想状态下即使采用30℃/s的冷却速度,合金层厚度依然≥5.6μm。预电镀Ni工艺可以改善了铝液的浸润性,减小合金层厚度,提高II型镀铝板表面铝层质量。预电镀Fe工艺会使得镀层整体质量较差,合金层厚度增加,局部出现裂纹和较大得空洞等缺陷,表面铝层疏松多孔,镀层表面十分粗糙。过时效处理工艺可以改善镀铝板钢基体的塑韧性,但其会使得合金层厚度有小幅度增加,表面铝层中微小孔隙等缺陷增多,此工艺应该根据镀铝基材中的C、N原子含量进行合理选择。镀铝板在弯曲加工时,合金层不论厚薄都必然会发生破碎断裂产生微裂纹,镀层在微裂纹处容易产生应力集中而被破坏,下表面镀层容易被拉裂,上表面镀层容易挤出脱落,随着合金层与基体厚度的增加,镀层越容易被拉裂或挤出脱落,随着表面铝层厚度增加,裂纹越不容易扩展贯穿整个表面铝层,镀层力学加工性能变好。
[Abstract]:In this paper, the continuous galvanizing simulator of Angang is used. In this paper, the effect of pre-plating Fe/Ni process before and after plating on the microstructure and mechanical properties of continuous hot-dip aluminum / aluminum-silicon coating by American steel couplet method and its feasibility in practical production were studied. At the same time, the thermodynamic and kinetic properties of Fe-Al intermetallic compounds in the process of coating formation were calculated and analyzed by various models, and the formation mechanism of the coating was further clarified. Finally, the finite element simulation of the three-point bending test was carried out by ANSYS Workbench software, and the cracking form and the influencing factors of mechanical processing properties of the coating were analyzed. The results show that during the formation of alloy layer, only Fe2Al5 phase and FeAl3 phase Fe _ 2Al _ 5 phase can nucleate and grow at the solid-liquid interface and form a single phase layer at the same time, and then the FeAl3 phase will nucleate at the interface between Fe2Al5 phase and liquid aluminum phase. The faster the cooling rate after plating is, the thinner the thickness of alloy layer is, and the cooling ability required for thinning the same thickness will increase exponentially when the cooling rate exceeds a certain degree. In ideal condition, the thickness of alloy layer is still more than 5.6 渭 m even if the cooling rate of 30 鈩，

本文编号：1799553