连铸工艺参数对φ390 mm GCr15大圆坯碳偏析的影响

    Effect of Continuous Casting Process Parameters on Carbon Segregation in φ390mm GCr15 Large Round Billet

    • 摘要: 研究了不同连铸工艺参数(拉速、二冷区电磁搅拌S-EMS、凝固末端电磁搅拌F-EMS和过热度)对φ390 mm的GCr15轴承钢大圆坯横截面上碳偏析的影响。结果表明:随着拉速的增大,连铸大圆坯横截面上碳偏析逐渐严重;当拉速从0.55 m/min降低到0.50 m/min时,铸坯中心和R/2处碳偏析系数分别减小了9.5%和4.2%,波动范围分别减小了39.9%和52.3%;S-EMS对连铸大圆坯横截面上中心和R/2处碳偏析波动范围有着重要影响,有S-EMS的铸坯中心和R/2处碳偏析波动比无S-EMS分别减小了33.2%和50.7%~64.6%;当F-EMS参数为500 A/2 Hz时,连铸大圆坯横截面上的碳极差最小;过热度为22~33℃时,低过热度能显著减小连铸大圆坯横截面上的碳极差,且过热度与碳极差呈线性正相关关系。

       

      Abstract: The effects of continuous casting process parameters on carbon segregation of φ390 mm round billet of GCr15 bearing steel were studied, mainly including the effects of drawing speed, electromagnetic stirring in secondary cooling zone(S-EMS), electromagnetic stirring at end of solidification (F-EMS) and superheat on carbon segregation.The results show that with the increase of the drawing speed, the carbon segregation of the cross section of the continuous casting billet is gradually serious; when the drawing speed decreases from 0.55 m/min to 0.50 m/min, the carbon segregation coefficient at the center and R/2 of billet decreases by 9.5% and 4.2% respectively, and the fluctuation range decreases by 39.9% and 52.3% respectively.S-EMS has an important influence on the fluctuation range of carbon segregation at the center and R/2 of the cross section of the continuous casting billet.Compared with those without S-EMS, the carbon segregation fluctuations at the center and R/2 of the billet are reduced by 33.2% and 50.7%-64.6%, respectively.When the F-EMS parameter is 500 A/2 Hz, the carbon range of the cross section of the continuous casting billet is the smallest.When the superheat degree is 22-33℃, the low superheat degree can significantly reduce the carbon range of the cross section of the continuous casting billet, and the superheat degree has a linear positive correlation with the carbon range.

       

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