玻璃包覆铁基合金微丝制备微熔池的稳定性

Stability of a micro molten pool for fabricating glass-coated Fe-based alloy microwires

  • 摘要: 保持微熔池稳定是采用玻璃包覆熔融纺丝法连续稳定制备微丝的前提.采用理论计算分析了感应加热器结构参数、加热电流、微熔池的体积、微熔池在感应加热器中的位置等因素对铁基合金微熔池温度和所受悬浮力的影响,获得了保持微熔池稳定的合理工艺参数.在合适的拉丝温度(1280℃左右)下,增大感应加热器锥角和下锥孔高度,减小感应加热器高度、下锥孔半径以及微熔池中心与下锥孔上端面之间的距离,均有利于提高铁基合金微熔池所受悬浮力;减小电流的同时减小微熔池的体积(质量),有利于减小重力与悬浮力差值.在本文研究条件下,整体感应加热器的合理结构尺寸为:感应加热器锥角120~130°,感应加热器高度12~14mm,下锥孔高度2~4mm,下锥孔半径3~4mm.微熔池中心与感应加热器下锥孔上端面之间的合理距离为4~6mm,合适的微熔池质量为1.5~2.0g.采用结构优化的整体感应加热器,并通过连续进料使微熔池的体积(质量)保持基本不变,实现了玻璃包覆铁基合金微丝的连续稳定制备.

     

    Abstract: To keep micro molten pools stable is a premise for fabricating glass-coated metal microwires continuously by the glass-coated melt spinning method. Theoretic calculation was used to analyze the effects of the structural parameters of an induction heater, heating current, pool volume (mass) and position in the induction heater on the temperature and levitation force of the Fe-based alloy micro molten pool. The levitation force of the micro molten pool, as the temperature is 1280℃, increases with the increase in cone angle and bottom hole height of the induction heater, as well as the decrease of the induction heater's height, bottom hole radius and distance from the molten pool center to the upper surface of the bottom hole, and reducing the heating current and the pool volume (mass) is beneficial to the decrease of the difference between gravity and levitation force. The appropriate structural sizes of the integral induction heater for preparing glass-coated Fe-based alloy microwires are the cone angle of the induction heater 120 to 130°, height of the induction heater 12 to 14 mm, bottom hole height 2 to 4 mm, and bottom hole radius 3 to 4 mm. The reasonable distance from the molten pool center to the upper surface of the bottom hole is 4 to 6 mm and the suitable mass of the Fe-based alloy micro molten pool is 1.5 to 2.0 g. Using the optimized integral induction heater and keeping the volume (mass) of the Fe-based alloy micro molten pool almost invariant by feeding continuously, glass-coated Fe-based alloy microwires are fabricated continuously and stably.

     

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