Viscosity and Viscosity Estimate Titanium-Bearing Model of Fluoride-Free and Mold Fluxes

The relationship between the binary basicity (CaO/SiO₂), TiO₂, Na₂O, Li₂O, MgO, MnO, B₂O₃ and viscosity for fluoride-free and titanium-bearing mold fluxes were systematically researched. The rotating cylinder method was employed in the experiment to measure the viscosity of the slag. The results indicate that Li₂O, B₂O₃ and Na₂O play major roles in decreasing viscosity, especially Li₂O, which is the most effective flux, while MgO and MnO exert little influence on viscosity. Meanwhile, it can be concluded that with increasing TiO₂ content, the viscosity of fluoride-free and titanium-bearing mold fluxes increases at first but then falls when the amount of TiO₂ is greater than 6.0%. Based on large amounts of experimental statistics of the viscosity of fluoride-free and titanium-bearing mold fluxes, an available model in literature for predicting the mold-slag viscosity was modified. This modified model can be used to predict the viscosity of fluoride-free and titanium-bearing mold fluxes. In fact, the predicted values approximate the observed values with a ±10.6% average deviation. Compared with the classical models, the average deviation is higher and it was found that the modified model can be used to estimate the viscosity of fluoride-free and titanium-bearing mold fluxes.     

Crystallization Temperature and Crystallization Ratio of Mold Flux

Moldfluxformsaliquidphaseinfiltratinginto thegapbetweenthemoldandstrand.Thelayerof fluxfilmonthemoldplateisasolidglassylayer,whilethelayerclosesttothestrandremainsliquid andacrystallizationlayerliesbetweenthistwolay ers[1-3].Thecrystallizationtemperatureo…     

Effects of Rare Earth Oxide on Viscosity of Mold Fluxes for Continuous Casting

The effects of RE (rare earth) oxide on viscosity of mold fluxes were investigated with a rotary viscometer. The results show that : (1) The viscositv of mold fluxes is remarkably inereased by RE oxide addition, especially when the mass fraction of RE oxide is more than 10%. (2) By addition of RE oxide, precipitation of the insohlble particles with high melting point from the molten slag with the decreasing of the temperature leads to the inerease of viscosity. Viscosity curve shows that RE oxide is soluble in some extent in mold fluxes. When RE oxide is in a state of supersaturation, the existence of insoluble particles also makes the viscosity of mold fluxes increase. (3) Not only the viscositv of nlold fluxes can be reduced, but also the capacity to dissolve and absorb RE oxide can be increased by Li2O, B2O3 and BaO. However, the contents of Li2O, B2O3, and BaO should be controlled to suitable levels. (4) The solidification temperature of mold fluxes can be increased by the addition of RE oxide, which is unfavorable to heat transfer and luhrication of mold fluxes between steel shell and mold.     

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The viscosity and smelting temperature of blast furnace slag with medium titanium and high alumina content were studied using RTW type of melt physical determinator and the influence pattern of different additive compositions on the viscosity and smelting temperature were obtained. The results show that a certain percentage of CaF2, MnO, MgO, Li2O added to the high aluminum and medium-titanium slag are conducive to the reduction of slag viscosity and smelting temperature. Considering the slag fluidity and additive costs, CaF2 and MnO are more suitable additives. The suitable percentage of each additive: the mass fraction of CaF2 is 0. 5%-1. 5%, the mass fraction of MnO is 2%-5%, the mass fraction of MgO is 1%-3% and the mass fraction of Li2O is 1%-2%.     

BaO对连铸保护渣熔化行为和结晶矿相的影响

实验研究和分析了BaO(2%～8%)对连铸结晶器保护渣(%:3～5MgO、1～2Al₂O₃、8Na₂O、3～4B₂O₃、2Li₂O、3～4C)熔化和结晶温度的影响以及无氟渣的结晶矿相。结果表明,随BaO含量由2%增加至8%,保护渣的熔化温度由1053℃降至1011℃,结晶温度降低较少,从954℃降至948℃;无氟渣的结晶矿相为黄长石,是铝黄长石(Ca₂Al₂SiO₇)、镁黄长石(Ca₂MgSi₂O₇)和钠黄长石(NaCaAlSi₂O₇)的固溶体,可通过调整渣膜中黄长石的析晶率,控制结晶器与坯壳间的传热。     

连铸保护渣组分对粘度的影响

根据合金钢连铸保护渣多组分组成特点,设计了CaO-SiO2-Na2O-CaF2-Al2O3-MgO-MnO-BaO渣系,研究了该渣系组成与粘度的关系。研究结果表明,该渣系保护渣的粘度在CaO/SiO2=0.6~1.1、CaF2=5%~15%、Na2O=2%~10%、MgO=0~5%、MnO=0~5%、BaO=0~7%范围内随着含量增加而降低;在MgO=5%~8%、MnO=5%~8%、BaO=7%~12%范围内,连铸保护渣的粘度基本不变。通过研究还得出了粘度与组分之间的回归方程,对连铸保护渣的设计具有积极的指导意义。     

含钛高炉渣熔化性温度的试验研究

含钛高炉渣的熔化性温度是影响高炉炉渣冶金特性的关键因素。以工业生产含钛高炉渣为原料,进行正交试验研究,其结果表明：随着碱度的提高,熔化性温度上升,粘度也升高;MgO从6%增加到8%或8.5%时,熔化温度曲线温度转折点即熔化性温度从1 435℃降低到1 380℃;TiO2含量在16%~20%的条件下,渣中MgO在8%左右,Al2O3含量在9%~13%之间,TiO2对炉渣粘度与熔化性温度影响不大。     

锰矿中多元素的X射线荧光光谱分析

以Li2B4O7作熔剂,采用熔片法制样,建立了锰矿物料中SiO2,CaO,MgO,Al2O3,TiO2,P2O5,MnO,BaO,Fe2O3的X射线荧光光谱分析方法,本方法采用国家标准样品及人工合成标准样品绘制了工作曲线,进行了精密度和准确度试验,其测定值与标准值相符,并有良好的精密度,完全满足生产检验要求。     

含氟保护渣与无氟保护渣的传热机制研究

综述了传统含氟保护渣和无氟保护渣的传热机制研究现状,比较了目前传统含氟保护渣和无氟保护渣传热机制的研究成果.在此基础上,提出了以适当的比例混合加入Li2O、B2O3和TiO2等氟化物替代溶剂,可以配制出满足连铸用的无氟保护渣.合适加入量:w(Li2O)为2%,w(B2O3)为7%,w(TiO2)为6%.     

非均相高钛渣的电导率和粘度

采用交流阻抗谱技术测量了含有固态TiC的非均相高钛渣的电导率,研究了TiC的浓度、粒度对炉渣电导率的影响,并测量了含有CaF2和部分氧化物添加剂的高钛渣的粘度.研究结果表明,TiC降低炉渣的电导率;渣中的负离子在TiC表面形成双电层分布,增加TiC的体积,它是炉渣粘度较大的原因之一.CaF2、CaO、MgO、MnO显著降低炉渣粘度,TiO2对炉渣粘度没有明显的影响.     

Crystallization Behavior in Fluoride-Free Mold Fluxes Containing TiO2/ZrO2

  The time temperature transformation (TTT) diagrams of fluoride free mold fluxes containing TiO2/ZrO2 were constructed through the confocal scanning laser microscope (CSLM) technique. It was found that the crystallization temperature of F free mold fluxes containing TiO2 or ZrO2 increases, while incubation time decreases with increasing basicity. The crystallization tendency increases with the zirconia addition in slag melt, as it may be thought that the addition solubility is limited in molten slag and the solid particles act as heterogeneous nucleation sites. Three types of crystal morphologies were observed, corresponding to different crystallization mechanisms. CaSiO3 and Ca3Si2O7 precipitate in the slag with low basicity, and Ca2SiO4 was formed with increasing basicity. The addition of TiO2 promotes the precipitation of CaTiO3. The logarithm of crystal growth rate increased with increasing isothermal temperature, suggesting that the crystal/melt interface reaction is the controlling step in the present experiment.     

含氟连铸保护渣黏度检测与预测模型

采用旋转柱体法对不同类型的含氟连铸保护渣黏度进行检测,并基于Arrhenius方程通过非线性回归分析建立了新的黏度预测模型,分析了组分变化对黏度的影响。结合模型计算和实验检测,建立了CaF₂?Na₂O?Al₂O₃?CaO?SiO₂?MgO渣系的等黏度图。结果表明,与传统的含氟连铸保护渣黏度预测模型相比,该模型计算的偏差在10%以内,当渣中w（CaF₂）超过20%时,偏差逐渐增大,主要由于氟化物挥发造成炉渣成分变化,最终黏度实测值与炉渣初始成分不符,造成模型无法对黏度有效预测。此外,研究发现,CaF₂的增加能显著降低炉渣黏度,而Al₂O₃和Na₂O对黏度的影响受CaF₂含量的限制。当w(CaF₂)>17%,炉渣黏度随Al₂O₃含量增加而减小,当w(CaF₂)<17%,Al₂O₃的增加使炉渣黏度显著增大;当w(CaF₂)>11.5%,炉渣黏度随Na₂O含量增加显著下降,当w(CaF₂)<11.5%,Na₂O含量变化对黏度的影响并不明显。此外,该等黏度图表明低黏度区w(CaF₂)接近14%。通过调整等黏度图中各组分比例,可以改善保护渣的黏度和流动性,供钢铁工业应用。      

连铸结晶器保护渣的凝固温度

研究了CaO-SiO2-Na2O-CaF2-Al2O3-MgO渣系凝固温度的影响因素。该连铸保护渣的凝固温度随渣中CaO/SiO2、Na2CO3和CaF2含量的增加而逐渐降低,加入5.5%-7.5%的MgO,可提高凝固温度的稳定性。     

X射线荧光光谱法测定FeCuNbSiB纳米晶

提出了用熔融制样 X射线荧光光谱法测定FeCuNbSiB纳米晶合金炉渣中TFe, CaO,MgO,SiO2,Al2O3,MnO,CuO,Nb2O5和TiO2的方法。讨论了玻璃熔片的制备、混合熔剂和脱模剂的用量、基体的吸收和增强效应校正,以及用人工配制的标准样品绘制校准曲线等问题。在最佳的分析条件下,测定了人工配制的标准样品中TFe,CaO,MgO,SiO2,Al2O3,MnO,CuO,Nb2O5和TiO2的含量,11次测定结果的相对标准偏差小于07%,所得的分析结果与标准样品的标准值相符合。用此方法分析了FeCuNbSiB纳米晶合金炉渣试样,用同一样品在完全相同条件下制备了11个熔片进行测量,其测定结果的相对标准偏差小于30%,所得分析结果与其他方法的测定值相一致。     

含TiO2无氟保护渣的传热研究及生产实践

在对结晶器无氟保护渣熔粘特性研究的基础上,研究了结晶器无氟保护渣渣膜的传热.即在保护渣熔粘特性的基础上利用添加TiO2来降低和控制铸坯及结晶器之间的热传递.结果表明:采用碱度在0.95～1.05范围内、TiO2含量为2.5%的结晶器无氟保护渣,不仅可保证连铸生产所要求的正常渣耗和结晶器进出水温差,而且铸坯表面质量良好.     

Effect of Al2O3/Na2O ratio and MnO on high-temperature properties of mold flux for casting peritectic steel

The influences of Al2O3/Na2O ratio and MnO content on high-temperature properties,such as melting,crystallization,heat transfer,and viscosity of mold flux for c...     

Mixed Alkali Effect in Viscosity of CaO-SiO2-Al2O3-R2O melts

Metallurgical and Materials Transactions B - The mixed alkali effects of Li2O, Na2O, and K2O on viscosity of CaO-SiO2-Al2O3 melts are investigated by rotating cylinder method. It is found that the...     

X射线荧光光谱法测定不锈钢渣样中多元素含量

以Li2B4O7作熔剂,采用熔片法制样,建立了不锈钢渣样中SiO2、CaO、MgO、Al2O3、TiO2、P2O5、MnO、Fe2O3、Cr2O3的X射线荧光光谱分析方法,本方法采用国家标准样品及人工合成标准样品绘制了工作曲线,进行了精密度和准确度试验,其测定值与化学验证值相符,并有良好的精密度,完全满足生产检验要求。     

Effect of Strong Basic Oxide (Li_2O, Na_2O, K_2O and BaO) on Property of CaO-Based Flux

Intraditionalconvertersteelmakingprocess ,therephosphorizationofliquidsteelcausedbyladleslagstakesplacebecausetheoxidabilityandbasicityofslagsaredecreasedwhenthedeoxidizingandal loyingoperationsofsteelarecarriedoutinladle .Atpresent ,mainmeasuresofcontrollingrephosphori zationincludeincreasingoriginalbasicityandoxid abilityofslags ,whichcanincreasethemeltingpoint ,viscidityofslagsandtheamountofworkfordeoxidizationandalloyforalloying .Atthesametime ,theslagswithhighoxidabilityincreasetheox ygen…     

特殊组分对低氟保护渣凝固温度和结晶性能的影响

 氟含量过高的连铸保护渣不仅加剧伸入式水口的侵蚀，而且对连铸操作环境带来危害，为了降低保护渣中过高的氟含量，需要开发低氟或无氟保护渣。为避免保护渣中氟含量降低后性能指标的恶化，需要寻求氟化物的替代组分以协调保护渣各项冶金功能的正常发挥。为此，以高氟保护渣为参照点，设计了4组低氟连铸结晶器保护渣渣样。通过检测这些渣样的熔点、粘度、转折温度、结晶温度和结晶率，分析和比较实验数据发现，在不同碱度下，B2O3、Li2O、Cr2O3、TiO2均能部分替代渣中的CaF2，获得CaF2质量分数为45%的低氟保护渣。CeO2不能作为保护渣中CaF2的替代组分。