GCr15轴承钢大方坯二冷工艺评估与优化

Evaluation and optimization of the secondary cooling process for GCr15 bearing steel

针对某钢厂断面尺寸250 mm×300 mm GCr15轴承钢连铸工艺,采用自主研发的喷淋测试平台对二冷区喷嘴进行了喷淋水量分布测试,建立了基于喷嘴实际水量分布的凝固传热数学模型,分析了喷嘴布置方式对连铸坯凝固行为的影响。结果表明,由于二冷1段内弧采用了单排“双喷嘴”的布置方式,加剧了铸坯横向冷却的不均匀性,由此提出将单排“双喷嘴”更换为单排“单喷嘴”的布置方式。经仿真计算,喷嘴配置优化后不仅改善了连铸坯的冷却不均匀性,而且铸坯角部温度得到提高,热塑性得以改善,有效降低了铸坯裂纹的发生率。

Aiming at the continuous casting process of GCr15 bearing steel with cross section size of250 mm×300 mm,the spray water distribution of nozzles in secondary cooling zone is tested using an independently-developed spray testing platform. A heat transfer model is established based on the actual water distribution of the nozzle,and the effect of nozzle arrangement on the solidification behavior of continuous casting bloom is analyzed. The results show that the unevenness of transverse cooling of bloom is aggravated by the arrangement of single row "double nozzles" in the first segment of secondary cooling. Hence,the arrangement of "double nozzles" is proposed to be replaced by "single nozzle". The simulation results show that the optimized nozzle configuration not only improves the cooling inhomogeneity of the bloom,but also increases the temperature at the bloom corner,which could improve the hot ductility and effectively reduces the occurrence ratio of the bloom crack.