石钢中碳高锰钢连铸坯表面纵裂纹成因及控制

摘要

通过对石钢公司大方坯连铸机生产现场的调查、跟踪、试验、取样和统计,认为以40Mn2H(K)为代表中碳高锰钢铸坯表面纵裂纹的主要原因是二冷制度控制不当、保护渣性能不良、钢水过热度高,制定了相应措施,进行工业试验.试验结果表明,中包钢水的过热度控制在15~30 ℃、二冷水各区分配比由33∶42∶25调整为32∶40∶28、保护渣渣耗量提高到0.5 kg/t、液渣层厚度提高到10 mm左右,能有效减轻中碳高锰钢的表面纵裂纹.%Based on the investigation, tracking, testing, sampling and statistic of Shisteel company billet continuous casting machine production site, the main causes of mekium-carbon High-Mn steel, 40Mn2H(K) for example, slab longitudinal face cracks are considered as the inappropriate control of secondary cooling system, poor performance of casting powder and high of superheat.In view of the above reasons, we have worked out some corresponding measures and carried on the industrial experiment.According to the industrial experiment results, the surface crack of High-Mn steel can be effectively reduced if superheat degree of molten steel in tundish is controlled at 15 ~ 30 ℃, secondary cooling water distribution ratio is adjusted from 33∶42∶25 to 32∶40∶28, casting powder consumption is increased to 0.5 kg/t, and thickness of liquid slag layer is increased to about 10 mm.