【作者】 王文学；

【导师】 王雨；

【作者基本信息】 重庆大学 ， 冶金工程， 2006， 硕士

【摘要】 为解决攀长钢Cr13不锈钢小方坯连铸坯因表面凹陷及微裂纹引起的表面质量问题,调研国内外不锈钢结晶器保护渣应用情况,研究保护渣主要性能以及连铸工艺对铸坯表面质量的影响。结合Cr13不锈钢的高温特性和小方坯连铸的特点,考虑攀长钢铸机参数和相关连铸生产工艺条件,开展了攀长钢Cr13不锈钢小方坯连铸用保护渣的研究。①利用DIL402C热膨胀分析仪、STA449C同步热分析仪和Gleeble-1500D热模拟试验机测试Cr13不锈钢中2Cr13钢的线性膨胀系数、主要相变温度以及高温力学性能等高温特性,分析Cr13不锈钢高温性能对铸坯表面质量的影响和铸坯表面凹陷以及微裂纹产生的机理,确定Cr13不锈钢用保护渣应重点考虑传热性能。②基于Cr13不锈钢小方坯连铸对保护渣性能的要求,在实验室设计出CaO-SiO2-Na2O-F--MgO-BaO-MnO-Al2O3渣系,研究保护渣的主要组成范围为:R=0.65～1.05、Na2O=4～12%、F-=0～4%、MgO=0～6%、BaO=0～8%、MnO=0～6%,其中Al2O3=1%,研究各主要调整组分及含量与熔化温度、粘度和转折温度的影响关系。③自行研究和设计测试保护渣渣膜导温系数的模拟装置,研究保护渣渣膜导温系数与温度变化的关系。利用X衍射仪和显微观察对从渣膜导温模拟装置上取得的渣膜进行较为全面的矿相和显微结构特征研究分析,并研究保护渣组分对矿相结构及其传热性能的影响。④确定适宜于攀长钢Cr13不锈钢小方坯连铸用保护渣的组成主要包括CaO、SiO2、Na2O、CaF2、MgO、MnO,保护渣性能如碱度R= [(∑CaO)/SiO2]=0.75,T半=1151±5℃、η1300℃=0.57±0.05Pa·s,Tb=1205±5℃。现场试验证明研究的保护渣所浇Cr13不锈钢铸坯因表面凹陷及微裂纹产生的铸坯返修率比其现用保护渣降低了15%,大大地提高了金属收得率和企业的经济效益。由此证明设计的保护渣能够满足攀长钢Cr13不锈钢小方坯连铸工艺要求。更多还原

【Abstract】 In order to solve surface depression and cracks on Cr13 stainless steel billet in Panchanggang I&S Co., domestic and overseas application of mold fluxes for stainless steel has been investigated., effect of mold fluxes and continuous casting process on surface quality of billet has also been studied. Considering the properties and performances of stainless steel at high temperature, the characteristics of Cr13 stainless steel billet casting, the parameters of continuous caster and manufacturing process in Panchanggng I&S Co., a research of mold fluxes used in Cr13 stainless steel billet casting has been carried out.①The DIL402C thermal dilatometer, STA449C thermal analyzer, the type Gleeble-1500D thermal simulation testing machine were employed to test the linear expansion coefficient, major phase change temperature, mechanic properties at high temperature of 2Cr13. The effect of these properties at high temperature on surface quality of billet and the mechanism of surface depression and crack formation on billet were analyzed. The study showed that heat transfer performance of mold fluxes for Cr13 stainless steel was vitally important.②Considering the requirement of mold fluxes for Cr13 stainless steel billet casting, the slag system of CaO-SiO2-Na2O-F--MgO-BaO-MnO-Al2O3 was designed. The bacisity of fluxes is 0.65～1.05. Na2O%, F-%, MgO%, BaO%, MnO% in mold fluxes were respectively controlled in 4～12%, 0～4%, 0～6%, 0～8%, 0～6%, and Al2O3% is arranged in 1%. The relationships between components and melting temperature, viscosity, breaking temperature had been studied.③The simulation setting used for testing coefficient of temperature conductivity was designed and used to study relationship between coefficient of temperature conductivity of mold fluxes film and temperature. By utilizing the X-ray diffractometer and microscopicexamination, the mineralographic composition and microscopic characteristics of mold fluxes film obtained from simulation setting were investigated in detail. The effect of components on microscopic characteristics and heat transfer performance of mold fluxes film has been analyzed.④The research results suggested that the chemical compositions of mold fluxes for Cr13 stainless steel billet casting in Panchanggang I&S Co. could mainly consist of CaO, SiO2, Na2O, CaF2, MgO, MnO. The basicity( R= [(∑CaO)/SiO2] ) can be更多还原