改善齿轮钢SAE8620H碳偏析的连铸工艺研究及应用

齿轮钢宏观碳偏析会加重带状级别,影响齿轮热处理变形。最根本解决方法是控制连铸坯碳偏析,在合适的连铸工艺拉速下采用优化结晶器电磁搅拌参数、动态末端电磁搅拌、控制钢水过热度及优化二冷配水的技术手段改善了连铸坯截面碳偏析指数及碳极差。实践结果表明,选择合适的连铸工艺参数及动态末搅技术能够大幅度提升铸坯内部质量,降低齿轮钢SAE8620H宏观碳偏析,达到9点碳极差不高于0.025%、碳偏析指数为0.95～1.05的水平,有效降低了齿轮钢带状级别。同时,轧制圆钢加工成齿轮后热处理变形量小、变形趋势好,产品质量得到了客户的认可。

Research and application of continuous casting process for improving carbon segregation of gear steel SAE8620H

Carbon macro-segregation of gear steel will aggravate the strip grade and affect the heat treatment deformation of gear. The most fundamental solution is to control the carbon segregation of continuous casting billet. Under the appropriate casting process speed, the technical means of optimizing the mold electromagnetic stirring parameters, dynamic end electromagnetic stirring, controlling the superheat of molten steel and optimizing the secondary cooling water distribution are adopted to improve the carbon segregation index and carbon range of continuous casting billet section. The results show that the selection of suitable continuous casting process parameters and dynamic end-stirring technology can substantially improve the internal quality of the cast billet and reduce the macroscopic carbon segregation of gear steel SAE8620H to the level of nine-point carbon polar difference no more than 0.025% and carbon segregation index 0.95-1.05, and effectively reduce the gear steel strip grade. At the same time, the heat treatment deformation of rolled round steel processed into gears is small and the deformation trend is good,The quality of products has been recognized by customers.