【作者】 陶贵华；

【导师】 李楠；

【作者基本信息】 武汉科技大学 ， 无机非金属材料， 2004， 硕士

【摘要】 随着钢铁工业的迅速发展，对钢材质量的要求越来越高。而洁净钢与超纯净钢是钢铁工业发展的重要方向之一。在冶炼过程中，耐火材料不可避免要与钢水接触，对钢水的洁净度有一定的影响。为了尽量减少它对钢水的污染，就有必要突出耐火材料的另一个功能—净化钢水的功能。碱性耐火材料对钢水增氧作用小，镁质耐火材料是最常见的碱性耐火材料，但其热震稳定性差。本研究希望加入SiC以提高其热震稳定性。 本论文所做的工作包括四个部分：第一部分是探讨MgO-SiC复合材料的氧化行为。第二部分是MgO-SiC浇注料的研究。第三部分是SiC含量对MgO-SiC复合材料热震稳定性的影响。第四部分是MgO-SiC复合材料的抗渣性能的研究。 在第一部分工作中，研究了温度、氧化时间以及结合剂种类对MgO-SiC复合材料的氧化行为的影响。结果如下： 1) 从1100℃开始两种结合剂结合的MgO-SiC材料开始增重，即开始氧化。但到1200℃以后，随着温度的升高质量变化率继续增大，增长速率逐渐变慢。 2) 氧化增重率与试样的显气孔率有关。随气孔率下降，质量变化的增长速度变缓。镁橄榄石形成所引起的体积膨胀与烧结均可能降低气孔率，从而减弱SiC的氧化。 3) MgO-SiC复合材料在氧化过程中，氧化面积及增重率随着氧化时间的增加而增加，但随着氧化时间的继续延长，试样氧化面积的增长速率和增重速率有所减缓。 4) MgO-SiC复合材料在1500℃条件下，随着保温时间的延长，氧化面积的增长速率及增重速率低于材料在1350℃时的氧化面积的增长速率，这是由于材料中镁橄榄石生成量较多所致。而此时结合剂对MgO-SiC复合材料氧化行为影响不显著。 在第二部分工作中，作者对分散剂及加水量对MgO-SiC浇注料流动性和物理性能的影响做了研究。结果表明：在以氧化硅微粉结合的MgO-SiC浇注料中分散剂C与G复合使用时，浇注料流动性好。同时其加水量控制在5％最为合适。分散剂种类对材料的物理性能有一定的影响。 在第三部分工作中，作者探讨了SiC含量对MgO-SiC复合材料热震稳定性的影响。 结果表明：随着SiC含量的增加，MgO-SiC复合材料的热震后的强度保持率也增加，即有利于提高材料的热震稳定性。当复合材料中SiC含量达到25％时，材料内部颗粒达到最紧密堆积，其物理性能最佳。 第四部分是MgO-SiC复合材料的抗渣性能的研究。结果表明： 1) 在多次渣蚀试验中，随着材料中的SiC含量的增加，镁橄榄石的生成量增加，CMS的生成量减少，有利于提高材料的抗渣性能。 2) MgO-SiC复合材料中作为结合剂的SiO₂微粉、熔渣中的SiO₂及SiC氧化生成的SiO₂与MgO反应生成M₂S，所引起的体积膨胀阻塞了材料中的气孔，可抑制渣的渗透。 3) 当硅微粉含量为5％时，材料的烧成前后的物理性能最佳，而控制SiO₂微粉加入量有武汉科技大学硕士学位论文第n页利于材料的抗渣性能。更多还原

【Abstract】 With the rapid development of iron and steel industry, the demand for increasing the quality of products has been taken into consideration. "Clean steel" and "extra-clean steel" making is one of the important direction for iron and steel industry. However, it is inevitable that refractories contact with molten steel during iron and steel making, so the refractories has influence on the quality of molten steel. In order to reduce its pollution to molten steel, another function of refractory-purifying molten steel must be highlighted. The Base refractories has little effect on the total oxygen content of steel but has poor thermal shock property.The article is divided into four parts: the first part is effects of MgO-SiC composites on oxidation; the second part is the study on castable MgO-SiC; the third part is effects of different SiC content on thermal shock property of MgO-SiC composites; the forth part is the study of resistance of MgO-SiC composites to slag attack.In the first part, three facts, including temperature, tune and bonder on oxidation of MgO-SiC composites are discussed. The results were listed as following:1) From 1100 C mass change ratio of the MgO-SiC composites bonded by two kinds of bonders began to increase, which means that MgO-SiC composites began to oxidize. From 1200 C, mass change ratio of the MgO-SiC composites continued to increase. However, the speed ratio increased slowly.2) With the decrease of the apparent porosity of the samples, the mass gam increased slowly. The expansion and the sintering due to the formation of M2S decreased the apparent porosity, so the oxidization of the SiC weakened.3) During the oxidization of MgO-SiC composites, the oxidizing area and the mass gain increased as the oxidizing time increased. But with the prolongation of the oxidizing time, the oxidizing area and mass gain increased slowly.4) The oxidizing area and mass gain at 1500 C was less than that at 1350 C, which was attributed to the formation of M2S. The bonder had no obvious effect on the oxidization of the MgO-SiC composite.In the second part the author studied the effects of dispersant and water on the physical properties of MgO-SiC castable. The results show: In the MgO-SiC castable bonded by ultra-fine, the flowability of the castable was best when both C and G dispersant were used together. The optimum content of the water is 5% in the castable. The kinds of the dispersants had certain effects on the physical properties of the materials.In the third part the author studied the effect of the content of the SiC on the resistance of MgO-SiC composite to thermal shock. The results show that with the increase of the SiC, the property of the resistance of the MgO-SiC composites to thermal shock was increased, whichmeans that it had benefits to increase the thermal shock of the composites. When the content of the SiC reached 25%, the grains were hi the close packing and the physical properties of the composite were best.The fourth part was the study of the resistance of the composite to slag attack. The results show:In the multiple slag tests, as the increase of SiC, the content of M2S was increased and the content of CMS was decreased. Thus the property of the slag resistance of the composite was increased.Microsilica used as bonder, SiO2 in the fused slag and SiO2 conducted from the oxidization of SiC reacted with MgO to form M2S. The volume expansion clogged the pore of the composites, so the penetration of the slag was inhibited.When the content of microsilica was 5%, the physical properties were optimum. The suitable content of microsilica had benefits to the slag resistance of the composites.更多还原