论文部分内容阅读
通过添加溶胶-凝胶法制备的Al2O3-ZrO2复合粉,对陶瓷型和颗粒型氧化锆质定径水口进行改性.对比研究了陶瓷型和颗粒型定径水口改性前后物理性能,矿物相组成和显微结构的变化,并通过现场连铸实验对四种定径水口损毁机理进行了探讨.结果表明:相较于颗粒型定径水口,陶瓷型定径水口的显气孔率较低,体积密度和耐压强度较高,热震稳定性较差,抗侵蚀和冲刷性能较好.通过添加Al2O3-ZrO2复合粉改性后的定径水口显气孔率降低,体积密度增加,耐压强度提高,颗粒型定径水口的热震稳定性有了较大的提升,热震次数约为改性前的1.5倍以上.通过对连铸现场实际使用35 h后的残样分析发现,陶瓷型水口损毁主要是由于热震稳定性差导致使用时发生炸裂,炸裂产生的裂纹引起一定程度的剥落和扩径.未改性颗粒型定径水口由于强度低和显气孔率高,剥落和扩径更为严重,添加Al2O3-ZrO2复合粉改性后生成的镁铝尖晶石增强相大幅度提高了颗粒水口的热震稳定性和抗冲刷侵蚀性能,连铸现场使用后几乎未扩径.
Through the addition of Al2O3-ZrO2 composite powder prepared by sol-gel method, the porcelain-type and particle-type zirconia sizing nozzles were modified.Comparing the physical properties before and after the modification of the ceramic-type and the particle sizing nozzles, Composition and microstructure changes of the four kinds of sizing nozzles were investigated by on-site continuous casting experiment.The results show that the porosity of the ceramic sizing nozzles is lower than that of the particle sizing nozzles, Bulk density and compressive strength, thermal shock resistance is poor, erosion and scouring performance is better.Adding Al2O3-ZrO2 composite powder modified sizing hole porosity decreased, bulk density increased, compressive strength The thermal shock resistance of the particle sizing nozzle has been greatly improved, and the number of thermal shocks is more than 1.5 times of that before modification.Through the analysis of the residual samples after 35 h of actual use in the continuous casting site, it is found that the ceramic type The nozzle damage is mainly due to the thermal shock caused by the poor stability of the use of the burst, the crack caused by the burst caused by a certain degree of flaking and expansion. Unmodified particle-type nozzle due to the low strength and apparent porosity, spalling and expanding more To be serious, add Al2 O3-ZrO2 composite powder generated after modification of magnesium aluminate spinel reinforcement phase greatly improve the thermal shock resistance of the particle nozzle and erosion erosion performance, almost no expanded diameter after continuous casting site use.