Due to the disadvantages of complexity,high maintenance and vast investment of the electro-hydraulic servo oscillator,a new mechanical device synchronously driven by double servomotors was proposed. The working princi...Due to the disadvantages of complexity,high maintenance and vast investment of the electro-hydraulic servo oscillator,a new mechanical device synchronously driven by double servomotors was proposed. The working principle of the non-sinusoidal oscillator was analyzed and the model of the oscillator was validated via simulation software.Then,taking advantage of resonance technology,the hinging force and moment were calculated. The results showed that the hinging force and driving moment reduced,which was useful in reducing the impact of the hinge and prolonging the service life of the bearing. Besides,the best initial spring pressure was 0. 9 times the mold gravity,which improved the oscillation system stability and reduced the load fluctuation and servomotor driving power.展开更多
With establishment of thermal and numerical simulation models,the influence of reduction amount on solidification structure,segregation and shrinkage porosity of continuous casting(CC)billets was investigated.The ther...With establishment of thermal and numerical simulation models,the influence of reduction amount on solidification structure,segregation and shrinkage porosity of continuous casting(CC)billets was investigated.The thermal–mechanical coupled simulation results indicated that with an increase in reduction amount,the temperature in the central area decreases,and the reduction efficiency firstly increases and then decreases,reaching the maximum value at reduction amount of 6 mm.Metallographic analysis showed that increasing the reduction amount is beneficial for the refinement of central solidification structure.Moreover,the internal cracks are more likely to appear at higher reduction efficiency.The X-ray computerized tomography results revealed that a higher reduction amount can significantly reduce the volume fraction and equivalent diameter of the central shrinkage porosities of CC billets and increase the sphericity of them.Simultaneously,the macrosegregation of carbon along the central line is improved as the reduction amount increases;while the reduction amount exceeds 8 mm,the segregation degree will not change any more.展开更多
利用几何相似比1:3.5建立的水模型和采用正交试验研究了32 t 8流中间包挡墙导流孔位置、孔径、倾角及仰角、挡坝及湍流控制器等因素对平均停留时间、死区比例的影响。实验结果表明,梯形挡墙方案和V型挡墙结构优化方案对滞止时间一致性...利用几何相似比1:3.5建立的水模型和采用正交试验研究了32 t 8流中间包挡墙导流孔位置、孔径、倾角及仰角、挡坝及湍流控制器等因素对平均停留时间、死区比例的影响。实验结果表明,梯形挡墙方案和V型挡墙结构优化方案对滞止时间一致性的都比空中间包和原型挡墙的效果好;V形挡墙的平均停留时间和死区比例优于梯形挡墙;采用挡墙上3个导流孔的高度为500、300、400 mm,孔径80 mm,倾角60°、65°、80°,仰角0°的梯形挡墙方案的综合优化效果较好。脱硫铁水-100 t顶底复吹转炉-LF-CC工业生产试验结果表明采用最佳的V形挡墙方案,铸坯中平均全氧含量由原型中间包的55.6×10^(-6)降至50.5×10^(-6)。展开更多
基金financially supported by the National Natural Science Foundation of China(51275446, 61503323 )National Natural Science Foundation of China and Baosteel Group Co.,Ltd.(U1260203)Natural Science Foundation of Hebe Province of China(E2016203492)
文摘Due to the disadvantages of complexity,high maintenance and vast investment of the electro-hydraulic servo oscillator,a new mechanical device synchronously driven by double servomotors was proposed. The working principle of the non-sinusoidal oscillator was analyzed and the model of the oscillator was validated via simulation software.Then,taking advantage of resonance technology,the hinging force and moment were calculated. The results showed that the hinging force and driving moment reduced,which was useful in reducing the impact of the hinge and prolonging the service life of the bearing. Besides,the best initial spring pressure was 0. 9 times the mold gravity,which improved the oscillation system stability and reduced the load fluctuation and servomotor driving power.
基金financially supported by the National Natural Science Foundation of China(Nos.52127807 and 52271035)National Science and Technology Major Project of China(No.J2019-Ⅵ-0023)the fund of the State Key Laboratory of Solidification Processing(Northwestern Polytechnical University)(No.SKLSP202107).
文摘With establishment of thermal and numerical simulation models,the influence of reduction amount on solidification structure,segregation and shrinkage porosity of continuous casting(CC)billets was investigated.The thermal–mechanical coupled simulation results indicated that with an increase in reduction amount,the temperature in the central area decreases,and the reduction efficiency firstly increases and then decreases,reaching the maximum value at reduction amount of 6 mm.Metallographic analysis showed that increasing the reduction amount is beneficial for the refinement of central solidification structure.Moreover,the internal cracks are more likely to appear at higher reduction efficiency.The X-ray computerized tomography results revealed that a higher reduction amount can significantly reduce the volume fraction and equivalent diameter of the central shrinkage porosities of CC billets and increase the sphericity of them.Simultaneously,the macrosegregation of carbon along the central line is improved as the reduction amount increases;while the reduction amount exceeds 8 mm,the segregation degree will not change any more.
