热轧带钢无酸洗还原退火热镀锌技术的发展现状

DEVELOPMENT OF HOT-DIP GALVANIZING TECHNOLOGY OF HOT-ROLLED STRIP BASED ON DIRECT REDUCTION ANNEALING WITHOUT ACID-PICKLIN

热镀锌板具备优良的表面质量和耐腐蚀性,广泛应用于建筑、家电和汽车等行业。在常规的“热轧-酸洗-冷轧-热镀锌”生产流程中,“酸洗”工序既污染环境又增加生产成本。此外,对于含Mn、Si和Cr等合金元素的高强钢在镀锌时,会在退火段发生选择性氧化降低镀锌基板的润湿性,导致镀锌板出现漏镀、凸点等缺陷。为解决上述问题,一项颠覆传统生产流程的热轧带钢无酸洗还原退火热镀锌技术被提出,这项新技术可以在降低能耗的同时减少酸洗废弃物排放,并将提高生产效率20%以上。围绕该技术中所涉及的热轧板氧化铁皮控制工艺、高效氢还原控制工艺、热镀锌控制工艺以及锌液成分设计等核心问题,对国内外取得的研究性成果进行了总结和评述,并指出其在工业化应用中的可操作性及发展前景。

The excellent surface quality and corrosion resistance of hot-dip galvanized strip is widely used in construction,household appliances and automotive industries.In the conventional production process of"hot rolling,acid-pickling,cold rolling,hot galvanizing",the acid-pickling process not only pollutes the environment but also increases the production cost.Additionally,the selective oxidation behavior of high strength steel containing Mn,Si and Cr etc.will decrease the wettability of strip surface in the annealing stage,resulting in the surface defects such as dew plating and bulge.In order to solve the above-mentioned problems,the hot-dip galvanizing technology of hot-rolled strip based on direct reduction annealing without acid-pickling is put forward,which is a noval technology to change the traditional production process.This technology can reduce the energy consumption and the emissions of acid-pickling waste,and then increase production efficiency by more than 20%.Focusing on the core problems of hot rolled sheet iron oxide scale control technology,high efficiency hydrogen reduction control technology,hot galvanizing control technology and zinc liquid composition design,the research achievements at home and abroad are summarized and reviewed,and the operability and development prospects of its industrial application are pointed out.