CaO-Al2O3-SiO2系渣中Al2O3含量对铝镁质浇注料侵蚀的影响

摘要：钢中添加适量铝元素可以提高其韧性与耐腐蚀性,但在冶炼过程中会影响炉渣中Al2O3含量而改变其与现行铝镁质浇注料的界面反应,制约钢种冶炼及品质提升。因此,采用静态坩埚法开展铝镁质浇注料的抗CaO-Al2O3-SiO2渣蚀实验,并结合热力学模拟计算探究Al2O3含量（w(CaO)∶w(Al2O3),C/A）变化对耐火材料渣蚀的影响规律,得到以下结论：随着熔渣中Al2O3含量的增加,铝镁质浇注料与熔渣反应界面越易形成更厚的高熔点隔离层,将耐火材料组分向熔渣中的直接溶解转变为间接溶解,有利于提升铝镁质浇注料的抗侵蚀性;当渣中的Al2O3质量分数在32%左右时,熔渣的侵蚀性总体较弱,但当渣中的Al2O3质量分数不小于36%时,熔渣对铝镁质浇注料产生了严重的渗透性,也易造成材料变质剥落。这为面向含铝钢冶炼用耐火材料的优化设计提供参考。     

高铝低硅CaO-Al2O3系熔渣对刚玉/六铝酸钙质浇注料的作用行为

摘要：由于高铝低硅CaO-Al2O3系熔渣对耐火材料的侵蚀损毁影响高铝含量低密度高强钢的安全冶炼生产,为此通过在刚玉质浇注料中引入六铝酸钙,开展六铝酸钙质浇注料与高铝低硅CaO-Al2O3系熔渣反应实验,并与铝镁浇注料进行对比研究了其作用行为。实验结果表明：刚玉 六铝酸钙浇注料具有优异抗渣性能。这主要是由于熔渣中大量的CaO被消耗,间接提高了熔渣黏度,并与刚玉 六铝酸钙浇注料反应生成的高熔点相CA2填充了气孔,阻挡了熔渣的渗透,实验结果与热力学模拟计算结果相吻合。六铝酸钙浇注料自身气孔率高,熔渣主要以渗透形式对六铝酸钙耐火材料造成破坏。因此,将刚玉骨料与六铝酸钙基质组合是有望成为低密度高强钢冶炼用钢包内衬候选耐火材料。     

CaO-Al2O3基钢液净化剂组成的优化

运用CaO-Al2O3-SiO2三元系的熔点和等αAl2O3相图,分析了CaO-Al2O3渣系净化剂降低钢液中氧化物夹杂的能力与其组成的关系。从热力学角度看,CaO/Al2O3比值高（1.6～2.0）,则αAl2O3低（≤0.02）,有利于钢液中氧化物夹杂的降低;从动力学角度看,CaO/Al2O3低（1.1～1.26）,则熔点低（〈1400℃）,有利于钢液中氧化夹杂的排出。净化剂组成的优化结果表明,适宜的CaO/Al2O3比值为1.41～1.74,净化剂αAl2O3较低（0.02～0.04）,熔点较低（〈1450℃）。工业性试验表明,优化后的净化剂净化钢液效果显著。     

顶渣对帘线钢中夹杂物塑性化的控制

以某钢厂生产的帘线钢铸坯试样为原料,使用硅钼棒炉对其进行顶渣熔炼实验,研究顶渣成分对CaO-Al2O3-SiO2 类夹杂物塑性化的影响。结果表明, 在顶渣碱度为0.8～1.2时,随着顶渣中Al2O3 质量分数的增加夹杂物中的Al2O3 质量分数也随之增加。当顶渣中Al2O3质量分数低于10%时,CaO-Al2O3-SiO2 类夹杂物的成分在塑性区范围,对应的此时钢液中的w［Al］s低于8×10-6。通过控制顶渣的成分可以把CaO-Al2O3-SiO2 类夹杂物的成分控制在塑性区内。     

LF处理过程中钢水增铝问题的研究

硅镇静钢及少量铝脱氧的钢在LF处理过程中会发生钢水中铝含量增加以及夹杂物组成改变的现象.通过理论计算和工业生产实践研究了不同的渣系、钢水成分、处理时间等对LF精炼过程增铝的影响,不同精炼渣系下钢中夹杂的组成,结果表明采用CaO-SiO2渣系LF处理过程几乎不发生增铝现象,而采用CaO-Al2O3渣系随着处理时间的延长以及钢种成分的区别,钢中铝有不同程度的增加,生产实践结果与理论计算趋势基本一致.采用CaO-Al2O3渣系精炼与CaO-SiO2渣系相比,钢中Al2O3夹杂数增加4倍,氧化物复合夹杂中w(Al2O3)提高113%,w(CaO)提高24.5%.在帘线钢72A以及HRB400、SS400钢的生产实践中加以应用,使得LF处理后72A的w(Al)小于0.000 5%,HRB400、SS400的小于0.003%,避免了有害夹杂物的形成,消除了在小方坯连铸过程中的水口堵塞现象.     

150 t钢包炉生产铝镇静纯净钢的实践

使用CaO-Al2O3系合成渣,选择合理的渣系CaO-Al2O3-SiO2-MgO,达到深度脱S的目的; 1600 ℃下精炼渣主成分比例m(CaO)/ m(Al2O3)=1.55时石灰达到饱和. 现行工艺可使总氧质量分数≤25×10-6; 钢水喂钙处理使夹杂物变性, 连续浇注能顺利进行, 并使钢的质量各向同性, 改善了钢板的深冲性能. 这些特点构成了珠钢钢包精炼纯净钢的特点.     

CaO-Al2O3基低反应性保护渣熔化及流动特性的成分控制区域研究

摘要：传统CaO-SiO2系保护渣在浇铸高锰高铝钢时,渣中SiO2易被钢中Al还原,造成保护渣成分改变和性能恶化,危害铸坯表面质量和连铸过程顺行。为了抑制钢 渣反应,旨在减少渣中氧化性组分的低反应性,CaO-Al2O3基渣系是重要选择方向。在评估高锰高铝钢凝固特性和传统反应性保护渣基础上,提出了低反应性保护渣基本性能要求,并采用单纯形法设计了CaO-Al2O3基保护渣系的试样组成。通过测试实验渣样的熔化特性和流动特性,获得了5组低反应性连铸保护渣熔化流动特性的成分控制区域。典型区域基本性能为：熔化温度（半球点温度）900～1100℃,1300℃的黏度0.1～0.2Pa·s,转折温度900～1150℃。     

SPA-H钢LF精炼过程非金属夹杂物行为研究

对武汉钢铁股份有限公司条材总厂"BOF→LF→CSP"工艺生产SPA-H钢2个炉次的LF精炼过程进行了系统取样,并利用Aspex自动扫描电子显微镜分析统计了钢中夹杂物的成分、尺寸、面积和数量。研究发现,当钢-渣反应和钢-炉衬反应达到平衡时夹杂物在CaO-Al2O3-MgO三元系相图中呈直线分布,通过对比2个炉次钢中夹杂物的转变,说明控制精炼渣成分和精炼时间,可以使部分Al2O3夹杂物进入CaO-Al2O3-MgO三元系低熔点区,并且在软吹过程中能够获得较好的夹杂物去除效果。     

不烧镁钙砖的抗精炼炉渣侵蚀性能

为了适应精炼钢包对镁钙材料日益增长的需求，通过感应炉抗渣实验研究了不同精炼渣系(CaO-SiO2和CaO-Al2O3)对不同组成的树脂结合不烧镁钙(MgO-CaO)砖侵蚀的影响，并借助显微镜和电子探针对熔渣熔蚀、渗透进行了研究。结果表明：对于CaO-SiO2渣，随着砖中Ca0含量的增加，砖的抗渣蚀能力增强，而CaO-Al2O3渣却恰好相反；无论对哪一种渣，熔渣的渗透深度都随着砖中CaO含量的增加而减小。     

低碱度低氧化铝精炼渣对帘线钢夹杂物控制

 研究了低碱度、低氧化铝精炼渣对帘线钢夹杂物控制情况。试验采用LD→LF精炼→软吹Ar→连铸工艺生产帘线钢,在碱度1.0、Al2O3质量分数为5%左右的精炼渣成分控制条件下,钢中酸溶铝AlS的质量分数控制在0.000 5%左右,进而控制夹杂物中Al2O3质量分数在22%以内,使得帘线钢中氧化物夹杂MnO-Al2O3-SiO2类、CaO-Al2O3-SiO2类复合夹杂物实现了良好的塑性化控制。根据分析,在帘线钢夹杂物去除方面,软吹氩处理对钢中CaO-Al2O3-SiO2系复合夹杂物去除效果比对MnO-Al2O3-SiO2类夹杂物更加明显;在成分控制方面,钢液中AlS含量随着炉渣碱度、炉渣Al2O3质量分数的升高而升高,而夹杂物中Al2O3质量分数会随着钢液中AlS含量升高而升高。     

Effect of Al2O3 content in CaO-Al2O3-SiO2 slag on corrosion resistance of alumina magnesia castable

The toughness and erosion resistance of steel can be improved by adding an appropriate amount of aluminum. However it will increase the content of Al2O3 in slag and react with the existing alumina magnesia castable, and affect smelting and quality of steel. Therefore, static crucible method was applied, corrosion experiments of the CaO-Al2O3-SiO2 slags on the alumina magnesia castable were carried out, and the influence of Al2O3 content (w(CaO)∶w(Al2O3), C/A ratio) on slag corrosion resistance was investigated by combining thermodynamic simulation. The following conclusions were obtained: with the increase of Al2O3 content in the slags, the thicker isolation layer with high melting point is easier to form at the reaction interface between alumina magnesia castable and the slags. The direct dissolution of the refractory components into the slags can be changed to indirect dissolution, which is conducive to improving the corrosion resistance of alumina magnesia castable. Nevertheless, when the content of Al2O3 in the slag is about 32 wt.%, the slag corrosion is generally weak, when the content of Al2O3 in the slag is more than 36 wt.%, the slag has serious permeability to the alumina magnesia castable, which is easy to cause the deterioration and spalling of the material. It provides guidance on the optimization and design of the refractories for Al containing steel smelting.     

Corrosion behavior of high alumina and low silicon CaO Al2O3 slags on corundum/calcium hexaaluminate based castables

Due to the corrosion of CaO-Al2O3 based slags on refractory materials is related to the safe smelting of low-density and high-strength steel with high aluminum, the reaction experiment of calcium hexaaluminate castables with high-alumina and low-silicon CaO-Al2O3 based slag was carried out by introducing calcium hexaaluminate into corundum castables, and it was compared with that of alumina magnesia castable. The experimental results agreed with that of thermodynamic simulation and show that corundum calcium hexaaluminate castable has excellent slag resistance. Because the corundum calcium hexaaluminate castable reacted with the CaO Al2O3 based slag and produced high melting point phase CA2, which consumed a large amount of CaO in the slag and increased the viscosity of the slag, and CA2 filled the pores and blocked the penetration of slag. The wear mechanism of the calcium hexaaluminate castable is slag infiltration due to the higher porosity. Therefore, the combination of corundum aggregates and calcium hexaaluminate matrix is expected to be a candidate refractory material for ladle lining of low density and high strength steel smelting.     

Inclusion evolution in 50CrVA spring steel by optimization of refining slag

In order to control the CaO-Al2O3 -SiO 2 -MgO system inclusions in 50CrVA spring steel in a lower melting temperature region, high temperature equilibrium experiments between steel and slag were performed in the laboratory, under the conditions of the initial slag basicity within 3-7 and the con-tent of Al2O3 between 18-35 mass%, to investigate the formation and evolution of this type of in-clusion.The results indicate that the total oxygen content in the steel decreases with the increase of slag basicity and the decrease of Al2O3 content in slags, and CaO-Al2O3 -SiO 2 -MgO inclusions tend to deviate from the low melting point region with the increase of Al2O3 content in slags.The most fa-vorable composition for the refining slag is composed of 51-56 mass% CaO, 9-13 mass% SiO2 , 20-25 mass% Al2O3 and 6 mass% MgO.In this case, the inclusions in 50CrVA spring steel are mostly in the low melting point regions, in which their plasticities are expected to improve during steel roll-ing.The MgO-based inclusions were observed in the steel matrix and the formation mechanism was theoretically and schematically revealed.It is also found that adding around 11 mass% of MgO into the refining slags is beneficial to reducing the refractory corrosion.Further work should be carried out focusing on the evolution rates of MgO-based inclusions.     

MgO加入量对Al_2O_3-MgO浇注料抗渣性的影响

以电熔白刚玉为主要原料,同时加入电熔镁砂细粉、铝酸钙水泥、α-Al2O3微粉、Si O2微粉等,保持镁砂细粉与白刚玉粉总加入量一定,通过改变镁砂细粉的加入量,研究了镁砂细粉加入量对Al2O3-MgO浇注料抗渣性的影响。研究结果表明:在Al2O3-MgO浇注料中加入一定量的镁砂细粉,高温下可以形成镁铝尖晶石,从而提高浇注料的抗渣侵蚀性。当镁砂细粉加入量在2%～6%时,浇注料的抗渣侵蚀性能最好。     

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In order to effectively protect the hearth lining of the blast furnace by using materials containing titanium, the corrosion behavior of slags containing TiO2 to Al2O3 ceramic cup was experimentally investigated through slag resistance test in static crucible and calculation of slag quantity by mass conservation of CaO. The effect of temperature, reaction time and slag binary basicity on the corrosion behavior was studied, and the corrosion mechanism was discussed. The results show that increasing temperature and prolonging reaction time can lead to an increase of corrosion of Al2O3 ceramic cup by the slags with TiO2, whereas the corrosion shows a decrease trend with the increase of slag binary basicity. The corrosion mechanism can be summarized as that: CaO and SiO2 in slag will react with Al2O3 from ceramic cup to form CA6, C2AS and CAS2; the formed CA6, C2AS and CAS2 will dissolve into slags?? some high-melting-point minerals such as MA and CA2 near the original brick layer of ceramic cup will be formed to make slag more viscous.     

Al2O3对酒钢低铝渣黏度的影响及热力学分析

为进一步分析Al2O3含量对低铝渣黏度的影响,以酒钢高炉渣成分为基础,通过试验和FactSage热力学软件分别研究了不同Al2O3含量炉渣的黏度、液相线温度、活度和冷却结晶过程的物相变化。结果表明,在本试验的低铝渣范围内,随Al2O3含量增加,炉渣黏度增大,在1 450 ℃以上黏度低于0.45 Pa·s,炉渣流动性和稳定性良好。Al2O3活度随Al2O3含量的增加而增大,相反,SiO2活度降低也证明炉渣聚合度的增大。炉渣的冷却结晶过程则表明,在液相线温度以上时,炉渣黏度主要与炉渣结构的复杂程度有关;在液相线温度以下时,黏度受液相炉渣结构和固相颗粒含量的共同影响。     

镁砂和硅微粉加入量对Al2O3-尖晶石浇注料性能的影响

在保持MgO化学成分总量不变的前提下，研究了镁砂细粉、SiO2含量对Al2O3－尖晶石浇注料性能的影响。结果发现：适量的镁砂细粉和SiO2微粉能提高浇注料强度，降低显气孔率，提高抗渣渗透性。