不同冷却工艺对热轧钢筋表面氧化锈蚀的影响

热轧钢筋在运输和储存过程中其表面会产生锈蚀,影响钢筋的使用及外观质量。分析了钢筋表面锈蚀产生的原因,利用扫描电镜和电子背散射衍射技术,对比了轧后空冷、气雾冷却和穿水冷却工艺下钢筋的抗锈蚀性能,分析了不同冷却工艺对热轧钢筋表面氧化铁皮厚度和结构的影响。结果表明:钢筋表面锈蚀与其表面氧化铁皮厚度、结构和完整性有关,与空冷及穿水冷却相比,气雾冷却工艺通过优化冷却路径,可以获得厚度为10~20 μm、主要由FeO+Fe₃O₄构成的致密复合氧化铁皮,能够对钢筋基体起到保护作用,从而能够延缓钢筋表面生锈,并降低生产成本。

Influence of different cooling processes on surface oxidation and corrosion of hot rolled reinforced bar

During transportation and storage of hot rolled reinforced bar, the surface will be corroded, which affects the quality and appearance of reinforced bar. The causes of corrosion on the surface of hot rolled reinforced bar were analyzed, and the corrosion resistance property of reinforced bar under air cooling, spray evaporation cooling and water cooling after rolling was compared by scanning electron microscopy and electron backscatter diffraction technology. The influence of different cooling methods on the morphology and structure of the surface oxide scale of hot rolled reinforced bar was analyzed. The results show that the red rust on the surface of the hot rolled reinforced bar is related to the thickness, structure and integrity of the surface oxide scale. Compared with air cooling and water cooling, the spray evaporation cooling process can obtain a dense composite oxide layer with a thickness of 10-20 μm and mainly composed of FeO+Fe₃O₄ by optimizing the cooling path, which can protect the steel matrix,and delay surface rusting and reduce production cost.