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酒钢CSP连铸连轧生产线生产热轧卷板过程中,阶段性出现表面纵裂纹缺陷,导致大量废品。研究过程对缺陷在厚度规格、宽度规格的统计规律进行了分析,对成品板材缺陷与铸坯缺陷宏观形态与分布特征进行了对比,对成品板材裂纹缺陷进行了金相分析,并使用扫描电镜对缺陷进行了形貌与能谱分析。最终确定此种裂纹发源于结晶器弯月面处凝固前沿不均匀的热力学条件,在结晶器锥度不合适、二冷区冷却不均匀条件下进一步发展,导致铸坯表面裂纹达到足以产生成品表面裂纹的程度。按照分析结果,针对钢水成分、主要浇注工艺参数、保护渣、连铸设备等各个方面制定出控制措施,在实际应用中取得了显著效果。
In the process of producing hot-rolled coil in the CSP continuous casting and rolling production line of Jiuquan Iron and Steel Co., Ltd., surface longitudinal crack defects occur periodically, resulting in a large amount of waste products. In the process of research, the statistical rules of the gauge of thickness and width are analyzed. The comparison of the macro-morphology and the distribution of the defects of the finished board and the defects of the slab is carried out. The crack of the finished board is analyzed metallographically and analyzed by scanning electron microscope Defects were morphological and energy spectrum analysis. Finally, this kind of crack originated from the thermodynamic condition of the front of the mold at the meniscus solidification. It was further developed under the condition of improper mold taper and uneven cooling in the secondary cooling zone, which resulted in the surface crack of the slab reaching enough to produce the finished surface crack Degree. According to the analysis results, control measures are formulated for various aspects of the composition of molten steel, the main pouring process parameters, mold flux and continuous casting equipment, and have achieved remarkable results in practical application.