热浸镀锌浴结晶特征、表面张力及流动性的研究
发布时间：2018-08-03 07:10
【摘要】：热浸镀锌技术发明至今已有300多年的历史,发展至今,仍然是钢铁防护最有效的方法。人们对热浸镀锌的研究多集中在镀层形成后的镀层组织及耐腐蚀性能,但是对镀层有重要影响的锌浴的研究甚少,鉴于此,本文基于国家基金项目“锌浴特征及镀层性能的预控制研究”的选题,对锌浴的结晶特性、表面张力及流动性进行研究,为预判模型的建立提供锌浴液态性能的理论基础。配制了本课题所需 Zn、Zn～0.05%Al、Zn～0.1%Al、Zn～0.2%Al、Zn～0.3%Al、Zn～0.5%Al、Zn～0.2%Al～0.2%RE、Zn～0.2%Al～0.3%RE合金,采用热分析法,测试、分析了锌及锌合金浴在430℃～520℃温度下的完整冷却曲线,并采用数学算法算出微分曲线,很据冷却曲线的特征值求出过冷度,分析了温度、铝及稀土对锌浴结晶特性及过冷度对锌浴组织的影响。采用吊板法测试了锌浴的表面张力,分析了温度、铝及稀土(RE)对锌浴表面张力的影响;利用金属型浇注模型浇铸法分析了锌浴的流动性,分析了温度、铝、稀土对锌浴流动性的影响。本论文通过研究得出以下结论:纯锌浴的有效形核过冷度在430℃时为16.1℃,远小于纯锌的均匀形核过冷度83.9℃,纯锌浴按非均匀形核冷却。在430～520℃,纯锌浴的过冷度为16.1～7.6℃,随着浇注温度的升高,过冷度递减,实际结晶温度越低。在浇注温度相同的条件下,铝含量的增加促进了锌浴的异质形核,使形核界面能降低,使锌浴在较小的过冷度下发生结晶形核,随着铝含量的增加过冷度依次降低,稀土比同等含量的铝更能降低锌浴的过冷度。表面张力随锌浴的温度的升高而降低;同等温度下,锌浴的表面张力比真空状态下小。少量的铝和稀土均可以降低锌浴的表面张力。锌浴的流动性随着温度的升高而增强,少量的铝元素可以降低锌浴的流动性,少量的稀土可以改善锌浴的流动性能,纯锌浴的流动性能最好,在430～520℃间,流动长度为36.9～49.1cm。
[Abstract]:Hot dip galvanizing technology has been invented for more than 300 years and is still the most effective method for iron and steel protection. Most of the studies on hot dip galvanizing are focused on the microstructure and corrosion resistance of the coating, but there are few studies on zinc bath which has important influence on the coating. Based on the national fund project "study on the characteristics of zinc bath and pre-control of coating properties", this paper studies the crystallization characteristics, surface tension and fluidity of zinc bath, which provides the theoretical basis for the establishment of pre-evaluation model of zinc bath liquid properties. In this paper, we have prepared the Zn / Zn ~ (0. 05) / Al ~ (2 +) Zn ~ (0. 5) and Al ~ (2 +) Zn ~ (0. 3) and Al ~ (2 +) Zn ~ (0. 2) Al ~ (2 +) Zn ~ (2 +) ~ (0. 2) Al ~ (2 +) Zn ~ (0. 3RE) alloy. The complete cooling curves of zinc and alloy zinc bath at 430 鈩，
本文编号：2160987
[Abstract]:Hot dip galvanizing technology has been invented for more than 300 years and is still the most effective method for iron and steel protection. Most of the studies on hot dip galvanizing are focused on the microstructure and corrosion resistance of the coating, but there are few studies on zinc bath which has important influence on the coating. Based on the national fund project "study on the characteristics of zinc bath and pre-control of coating properties", this paper studies the crystallization characteristics, surface tension and fluidity of zinc bath, which provides the theoretical basis for the establishment of pre-evaluation model of zinc bath liquid properties. In this paper, we have prepared the Zn / Zn ~ (0. 05) / Al ~ (2 +) Zn ~ (0. 5) and Al ~ (2 +) Zn ~ (0. 3) and Al ~ (2 +) Zn ~ (0. 2) Al ~ (2 +) Zn ~ (2 +) ~ (0. 2) Al ~ (2 +) Zn ~ (0. 3RE) alloy. The complete cooling curves of zinc and alloy zinc bath at 430 鈩，
本文编号：2160987
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