钢的软接触电磁连铸技术

介绍了软接触电磁连铸技术并分析了其作用原理,该技术可有效提高铸坯的表面质量,着重分析探讨了工业上实现钢的软接触电磁连铸在结晶器结构、材质以及电磁场参数等方面需要解决的关键问题,并介绍了该技术的最新研究成果:高频调幅磁场电磁连铸技术和无结晶器振动的电磁连铸技术.     

Incoloy800H高温耐腐蚀合金电磁软接触连铸技术的实验研究

通过分析Incoloy800H合金与碳钢等材质的电导率差异性,以及Incoloy800H合金电磁软接触连铸试验结果,证实了镍铬铁基高温耐腐蚀合金电磁软接触连铸的可行性。采用电磁感应法对切缝式结晶器内的磁场分布进行了测量,得出不同电源功率和磁场频率对磁场大小和分布的影响效果,从而选取出适当的电磁参数进行了Incoloy800H电磁软接触连铸对比试验。试验结果表明,当电源功率为66 kW,频率为20 kHz时,铸坯表面质量明显提高,表面振痕明显减轻,凹陷和表面裂纹等缺陷消失。当电源功率增加至100 kW时,铸坯表面质量下降,出现了波浪状振痕和切缝棱边。     

External pressure responsive device based on tunable organic inverter using soft contact lamination

A voltage tunable device which operates by external pressure based on a diode-connected load inverter is successfully fabricated by connecting two transistors adopting bridge-structured polymeric stamps with gold electrodes. When pressure is applied to the polymeric stamp in the drive transistor, the effective channel length between the source–drain electrodes decreases such that the source–drain current is increased and the voltage transfer curves of the inverter are shifted in the positive direction. Thus, a voltage tunable device (or a pressure sensitive inverter) is achieved, because the output voltage of the load inverter comes to have a corresponding relation with the applied pressure. In addition, the sensitivity of this pressure responsive device can be improved by changing the thickness of the polymeric stamp.     

A tunable organic inverter based on groove patterned pentacene thin film transistors using soft-contact lamination

Organic zero drive load inverters based on pentacene thin film transistors with periodic groove patterned dielectrics are fabricated using nanoimprinting and soft-contact lamination methods. Depletion mode transistor behavior is achieved when the current direction is parallel to groove direction and enhancement mode transistor behavior is achieved when the directions are crossed. An organic inverter is created after connecting two soft-contact laminated transistors. The electrical performance of the drive transistor can be varied and the organic inverter is tunable. This is done by utilizing a PDMS stamp with the source-drain electrode and changing the angle between the current direction and groove direction. The gain and symmetry of the VTC is improved by using an enhancement mode transistor where the source-drain electrode formed by thermal evaporation instead of being a soft contact-laminated device.     

电磁软接触方坯连铸实验研究

简要介绍了软接触电磁连铸技术的原理,分别从电源功率、结晶器切缝形式、弯月面位置、线圈匝数四个方面阐述了其对结晶器内磁感应强度和作用范围的影响,在此基础上进行了Sn-10%Pb合金和0.8%C钢拉坯实验,结果表明铸坯表面质量明显改善,振痕为传统连铸的10%,角部裂纹消失.     

软接触电磁连铸对铸坯表面质量的影响

为改善铝基复合材料铸坯的表面质量,采用割缝式结晶器并在初始凝固区域分别施加等幅高频磁场和调幅磁场进行软接触电磁连铸实验。结果表明,施加等幅高频磁场能够有效提高铸坯的表面质量,随着输入电流从30 A增加到80 A,铸坯表面质量提高,得到表面光洁的铸坯,而施加高频调幅磁场,铸坯表面光亮度提高,但铸坯表面会出现周期性的振痕,且振痕出现的频率与调幅波的频率有关,频率越高,振痕的间隔就越小。     

颗粒增强铝基复合材料的电磁连铸研究

用原位反应合成法制备(Al2O3 Al3Zr)p/Al颗粒增强铝基复合材料,在半连铸过程施加低频交变电磁场进行搅拌,改善增强颗粒在基体内的分布状态,并在结晶器初始凝固区域施加高频电磁场实现软接触连铸以改善铸坯的表面质量.SEM分析显示:施加电磁搅拌后凝固组织致密,颗粒增强相的数量增加,颗粒细化、分布趋于均匀.施加的高频磁场使得单纯使用电磁搅拌产生的表面粗糙现象消失,铸坯表面质量显著改善.     

圆坯电磁软接触连铸结晶器高频磁场分布

通过实验检测和数值模拟方法研究圆坯电磁结晶器切缝形式、切缝宽度、切缝数量及切缝长度对圆坯电磁软接触结晶器内高频磁场分布的影响,为软接触结晶器优化设计提供磁场理论依据.结果表明:切缝数增加可提高透磁性和均匀性;增大缝宽对透磁性影响不明显,但降低均匀性;缝长只在一定范围内对透磁性有影响.     

电磁连铸冶金技术及应用现状

论述了电磁技术在连铸过程中的应用现状,介绍并分析了电磁搅拌、电磁制动和软接触电磁连铸技术的特点,同时对国内外钢的电磁连铸技术应用现状进行了评述。