连铸保护渣吸附Al_2O_3夹杂能力的研究

研究了保护渣吸附不同质量分数Al2O3夹杂对其熔化温度、黏度、表面张力和结晶性能的影响.实验结果表明,保护渣吸附Al2O3夹杂后,熔化温度上升,黏度增加,表面张力有下降的趋势;当碱度在0.85～1.17时,保护渣吸附夹杂后熔化温度和黏度变化幅度不大,具有较好的吸附能力;碱度在0.92～1.07时,保护渣表面张力的变化较小,有利于夹杂物的吸附,是保护渣吸附夹杂物的适宜碱度范围;随Al2O3夹杂的增加,渣中枪晶石和硅灰石数量减少.     

超低碳钢新型连铸保护渣的开发

采用BN替代碳质材料 ,作为连铸保护渣的骨架粒子 ,研究开发出一种新型的超低碳钢连铸保护渣·新型连铸保护渣在绝热保温性能、熔化特性、粘性特征、夹杂物吸收能力和结晶性能等方面与传统连铸保护渣十分接近·新型连铸保护渣 ,可以彻底解决超低碳钢结晶器内钢液增碳和铸坯表面渗碳问题 ,而且不会发生超低碳钢结晶器内钢液增硼和铸坯表面渗硼问题·新型骨架粒子BN可以使连铸保护渣JRBW增大、熔化速度降低、粘度减小、Al2 O3 吸收速率增大、熔化温度降低、凝固温度降低、结晶温度降低     

BaO在连铸保护渣中的作用

本文研究了BaO在连铸结晶器用保护渣中的作用。重点考虑了BaO对保护渣的熔化温度、粘度、吸收夹杂能力和玻璃态形成的影响。 实验结果表明,保护渣中含有一定数量的BaO,可以降低其熔化温度、粘度,阻碍渣中高熔化温度质点的形成及熔渣的结晶,因而将增加保护渣吸收夹杂的能力,改善熔渣膜在结晶器与铸坯间的润滑。     

B2O3对无氟CaO-Al2O3-BaO基保护渣性能的影响

借助高温物性测试仪、黏度仪、原位热分析仪及傅里叶变换红外光谱仪等,研究了B₂O₃含量对无氟CaO-Al₂O₃-BaO基保护渣熔化温度、黏度和结晶性能的影响。结果表明,当B₂O₃含量为7%时,无氟CaO-Al₂O₃-BaO基保护渣熔化温度、黏度和结晶性能最佳。     

结晶器保护渣结晶温度的影响因素

利用热丝法熔化温度测定仪研究了保护渣结晶温度的影响因素,得到各种成分对保护渣结晶温度的影响规律及影响程度·研究表明,随着碱度及渣中NaF和CaF2含量的增大,保护渣结晶温度逐渐升高;随着渣中Al2O3,MgO,Na2O,K2O,BaO,MnO,B2O3含量的增大,保护渣结晶温度逐渐降低;随着渣中Li2O含量的增大,保护渣结晶温度先降低,2%时结晶温度最低,而后逐渐升高·     

Influence of Na2O on Properties of CaO-AI2O3 Slag

分析了向CaO-Al2O3基熔渣中添加Na2O对熔渣性能的影响,并比较了几种不同的添加剂对渣系黏度的影响.研究表明：w（CaO）/w（Al2O3）=1.1时,渣系中随着Na2O含量的增加,CaO-Al2O3渣系的黏度先降低后升高,在Na2O质量分数为4%处出现极小值;Na2O的添加还会导致CaO-Al2O3渣系的熔化温度升高;Na2O,Li2O和MgO都可以降低CaO-Al2O3渣系的黏度,其降低渣系黏度的能力由大到小依次为Li2O〉Na2O〉MgO.综合考虑Na2O对渣系黏度和熔化温度的影响,Na2O在CaO-Al2O3渣系中的加入量以不超过4%为宜.     

Na_2O对CaO-Al_2O_3基渣系性能的影响

分析了向CaO-Al2O3基熔渣中添加Na2O对熔渣性能的影响,并比较了几种不同的添加剂对渣系黏度的影响.研究表明:w(CaO)/w(Al2O3)=1.1时,渣系中随着Na2O含量的增加,CaO-Al2O3渣系的黏度先降低后升高,在Na2O质量分数为4%处出现极小值;Na2O的添加还会导致CaO-Al2O3渣系的熔化温度升高;Na2O,Li2O和MgO都可以降低CaO-Al2O3渣系的黏度,其降低渣系黏度的能力由大到小依次为Li2O>Na2O>MgO.综合考虑Na2O对渣系黏度和熔化温度的影响,Na2O在CaO-Al2O3渣系中的加入量以不超过4%为宜.     

B_2O_3对含钛低镁渣系流动性的影响及其机理研究

基于京唐现场渣中主要氧化物成分,采用内柱体旋转法对CaO-SiO2-15.2%Al2O3-4.8%MgO-TiO2-B_2O_3(质量分数)渣系进行黏度试验,结合Factsage软件热力学分析,探究TiO2和B_2O_3对低镁渣系黏度、熔化性温度和活化能的影响及影响机理。研究结果表明:质量分数为0~4.0%的TiO2使低镁渣系黏度、熔化性温度和活化能均降低;质量分数为0~2.0%的B_2O_3能降低含钛低镁渣系黏度和熔化性温度;含钛低镁渣中B_2O_3质量分数为1.0%左右较为合理。     

B2O3对高铝钢连铸保护渣理化性能的影响

高铝钢连铸过程中,为了避免或减轻钢液中Al与保护渣中SiO2发生反应,设计了低SiO2、高Al2O3含量的高铝钢连铸保护渣,通过添加适量的酸性氧化物B2O3协调熔渣酸碱性,利用实验分析了B2O3含量对高铝钢保护渣熔融特性、黏度特性及渣膜传热特性的影响。结果表明,B2O3含量在4%～10%时,随着B2O3含量增加,保护渣熔化温度、黏度、黏流活化能均降低,渣膜热流密度增加;保护渣的等温转变曲线(TTT曲线)向孕育时间增加的方向移动,晶体生长速率降低;实验条件下,增加B2O3含量可抑制保护渣中CaF2的析出。     

中薄板坯连铸保护渣研究

系统地研究了中薄板坯连铸保护渣的化学成分与理化性能,熔化温度、熔化速度和粘度的关系,探讨了保护渣中的 Al2O3、F-、碳质量分数及碱度的大小对保护渣理化性能的影响,得到了优化的保护渣成分.为开发满足现场工艺要求的中薄板坯连铸保护渣提供理论依据和指导.     

中薄板坯连铸保护渣研究

系统地研究了中薄板坯连铸保护渣的化学成分与理化性能,熔化温度、熔化速度和粘度的关系,探讨了保护渣中的Al2O3、F-、碳质量分数及碱度的大小对保护渣理化性能的影响,得到了优化的保护渣成分,为开发满足现场工艺要求的中薄板坯连铸保护渣提供理论依据和指导。     

Solidification and crystallization properties of CaO-SiO2-Na2O based mold fluxes

Crystallization properties play an important role in keeping a smooth running of continuous casting process and high surface quality of cast strands. To reduce fluorine pollution in slag, a new type of CaO-SiO₂-Na₂O (CSN) based mold flux was studied. The solidification and crystallization properties, including crystallization temperature, crystallization ratio and solidification mineragraphy, were measured, which were compared with the CaO-SiO₂-CaF₂ (GF) mold flux. The results show that the crystallization performance is equal to the high fluoride mold powder and CSN can be used for peritectic steel grades sensitive to longitudinal cracking in continuous casting.     

保护渣性能对结晶器内传热的影响

在实验室模拟研究了结晶器内酸性保护渣的传热情况。结果表明：增加保护渣的粘度、提高保护渣的凝固温度，结晶器与坯壳之间渣膜的传热系数和热流密度都减小而热阻增加，通过调整保护渣的性能，可调节渣膜的传热系数，使其适应连铸坯生产的要求。     

Effect of CeO_2 on heat transfer and crystallization behavior of rare earth alloy steel mold fluxes

To improve the heat transfer capability and the crystallization property of the traditional mold flux, CaF_2 was replaced with B_2O_3. Then, the influences of CeO_2 on the heat transfer and the crystallization of the CaF_2-bearing mold flux and the new mold flux with 10 wt% B_2O_3 were studied using a slag film heat flux simulator and X-ray diffraction(XRD). The results revealed that the addition of CeO2 reduced the heat transfer by increasing the solid slag thickness and the crystallization of two mold fluxes. However, CeO_2 had less effect on the B_2O_3-containing mold flux compared with the CaF_2-bearing mold flux. According to the analyses, the CeO_2 contents in the CaF_2-bearing mold flux and the B_2O_3-containing mold flux should not exceed 8 wt% and 12 wt%, respectively. Therefore, these experimental results are beneficial to improve and develop the mold flux for casting rare earth alloy steels.     

CaO-SiO_2-Na_2O-CaF_2-Al_2O_3-MgO渣系的粘度和结晶温度

采用CaOSiO2Na2OCaF2Al2O3MgO渣系,用差热分析仪测定熔渣的结晶温度,用粘度测定仪测定熔渣的粘度,研究结晶温度和粘度与碱度、w(Na2CO3)、w(CaF2)、w(Al2O3)和w(MgO)之间的关系,并得到相应的回归方程·利用这两个回归方程,可以预测连铸保护渣的结晶性能和粘性特征·化学成分通过改变粘度,来影响晶核形成速度和晶体成长速度,从而决定了熔渣的结晶性能·结晶温度随着粘度的减小而升高·渣系中只有MgO可以在减小粘度的同时降低结晶温度     

聚丁二酸丁二醇酯(PBS)交联改性研究

采用化学方法对聚丁二酸丁二醇酯(PBS)进行交联改性,交联剂为过氧化苯甲酰(BPO).研究了交联剂添加量对交联体系性能的影响.采用溶胀法、差示扫描量热法、X射线衍射、平板流变仪等手段对交联后PBS的凝胶含量、结晶和熔融行为、动态流变性能进行了研究.结果表明:随着BPO添加量的增加,交联PBS的凝胶含量升高,复数黏度、储能模量和损耗模量均显著增大;结晶度和熔点降低,但结晶温度有所提高.     

高铅渣物理化学性能测定的偏差规律

为探明造成高铅渣物理化学性能测定中实际值与理论值偏差的原因,本研究配制了Pb O-Fe Ox-Ca OSi O_2-Zn O系渣。利用TG-DSC热重差热分析仪分析了不同组分含量熔渣的失重变化规律,采用FACTSage软件计算炉渣熔点、粘度,并与实验测定结果进行了对比,分析了性能偏差规律。研究结果表明,对w(Pb O)=20%~40%的中、高铅渣,熔渣在736~1 450℃时铅的挥发率大约15%~16%;当w(Fe O)/w(Si O_2)设置在1.29~2.05和w(Ca O)/w(Si O_2)=0.40时,实际测定的渣熔点与炉渣挥发后理论熔点之间的偏差(ΔT_(a-vv))介于+34~+190℃,实测粘度与理论粘度偏差(Δη_(a-vv))介于+0.17~0.32 Pa·s;而w(Ca O)/w(Si O_2)=0.80时,ΔTa-vi值较小,介于+3~+92℃,实测值更接近理论值。依据不同熔渣组分在给定温度下的挥发规律以及ΔT_(a-vv)和Δη_(a-vv)偏差结果,可以对给定的初始渣组分的实际熔点及粘度值进行预测,并可根据实测值来预测可能的渣组分。     

Shear-thinning behavior of the CaO-SiO2-CaF2-Si3N4 system mold flux and its practical application

Satisfying the mold-flux performance requirements for high-speed continuous casting necessitates the development of a new non-Newtonian-fluid mold flux with shear-thinning behavior, i.e., a mold flux whose viscosity is relatively high under lower shear rates and relatively low under higher shear rates. In this work, a mold flux that exhibits shear-thinning behavior was developed by adding different amounts of Si3N4 to the CaO-SiO2-CaF2 mold flux. The shear-thinning behavior was investigated using a rotational viscometer. In addition, the microstructure of the newly prepared slags was studied by high-temperature Raman spectroscopy and X-ray photoelectron spectroscopy. The results showed that the mechanism of shear-thinning was attributable to a temporary viscosity loss caused by the one-way shear stress, whereas the corresponding magnitude of shear-thinning was closely related to the degree of polymerization (DP). Finally, the non-Newtonian fluid mold flux was used for laboratory casting tests, which revealed that the mold flux could reduce slag entrapment and positively affect the continuous casting optimization.