连铸保护渣凝固收缩特性89047.docVIP

重庆大学本科学生毕业论文 连铸保护渣凝固收缩特性 学 生：青雪梅 学 号指导教师：何生平 讲师 专 业：冶金工程 重庆大学材料科学与工程学院 二00六年六月 Graduation Thesis of Chongqing University Performance of Solidification Contraction of Mold fluxes during Continuous Casting of Steel Undergraduate:Qing Xuemei Supervisor: He Shengping Major: Metallurgy Engineering College of material Science and Engineering Chongqing University June 2006  摘 要 连铸保护渣在冷凝析晶过程中，由于结晶体、玻璃体结构的差异导致析晶过程中出现体积收缩或膨胀，由此产生的气孔将显著影响保护渣对铸坯的传热。本研究作为一种探索性实验，制定了保护渣凝固收缩特性的测试方法（通过测出保护渣结晶体、玻璃体密度求体积变化率）针对与枪晶石熔化温度相近的矿相，设计出五种不同碱度与氟含量的保护渣系（CSF、CSN、NCS、CTS、CT系）测出各渣的凝固收缩情况以及与结晶性能相关的参数，结合实验数据分析研究保护渣的组分及结晶性能对凝固收缩性能的影响。实验结果表明：（1）在保护渣的玻璃体向结晶体的转化过程中，出现了体积膨胀与体积收缩两种现象，体积收缩还是膨胀与保护渣的成分密切相关。（2）体积膨胀渣系有CSF、CSN、CT系，体积收缩渣系有NCS、CTS系，各渣系间体积变化率均不同。（3）同渣系，组分含量不同，体积变化率也不不同。（4）保护渣的结晶性能与凝固收缩情况密切相关。（5）保护渣的断面形貌反应了析晶过程中渣体积变化情况。（6）不同冷却速度下获得的同一凝固相的密度不同。 保护渣，凝固，密度，收缩，膨胀 ABSTRACT during continuous casting of steel, because of different structures between the crystal and vitreous body, there is volume contraction or volume increase. The voids which generate in the volume changing process remarkably affect the heat transfer between mold fluxes and the casting strand. In this paper, a test method was designed to appraise the contraction performance of the mold fluxes, and five series of mold fluxes which have different basicity and fluorine content were designed to test the contraction performance and crystallinity of them. The five series of mold fluxes were named CSF、CSN、NCS、CTS and CT. The results were as follows :(1)There are two phenomenon in the solidifying process of the mold fluxes, some are volume contraction and some are volume increase, volume contraction or volume increase are determined by the components of the mold fluxes .(2) In the solidifying process, the systems of CSF、CSN、CT are volume increase while the systems of NCS、CST are volume contraction .Different systems have different volume change case.(3)In the same mold fluxes system, the mold fluxes which have d