【摘要】 部分稳定氧化锆(PSZ)因具有耐高温、优良的抗侵蚀性以及良好的抗热震性而广泛用于连铸用定径水口。实验针对当前PSZ定径水口使用寿命短、易炸裂、抗冲刷性能差以及扩径快等问题,采用连铸现场取样分层分析研究的方法,借助SEM及XRD分析技术,对氧化锆质定径水口的损毁机理进行了系统的分析研究。研究结果表明:高温下稳定剂MgO首先脱溶到界面,固溶的CaO稳定剂分布均匀;随着熔渣渗入,脱溶的MgO稳定剂与固溶的CaO稳定剂发生固溶置换;随着侵蚀进一步加剧,CaO与熔渣反应完后MgO又与熔渣反应而脱溶。稳定剂的不断脱溶,导致氧化锆失稳,由立方相转变为单斜相,相变产生体积效应,从而形成裂纹,氧化锆颗粒破裂,水口强度大幅度下降,发生溶解和剥落。更多还原

【Abstract】 Partially stabilized zirconia(PSZ) has been widely used in non-swirl nozzle for continuous casting due to its high temperature resistance,high erosion and corrosion resistance,and high thermal shock resistance.At present,PSZ non-swirl nozzle has such problems as its limited service life,liability to burst,poor anti-erosion quality,and quick expansion of inner diameter.This article studies the wearing mechanism of non-swirl nozzle by sampling from the casting site and researching each stratum with SEM and XRD.It is demonstrated that the desolvation of MgO crops up in the course of serving at high temperature,while CaO stays stable in ZrO2.After the penetration of the slag,substitutional solid solution occurs between desolvated MgO and uniformly solvated CaO.The slag reacts with MgO to cause exsolution after CaO is consumed with further erosion & corrosion.Desolvation of stabilizers would cause a transformation of zirconia in its phase from cubic to monoclinic.As a consequence,cracks appear and strength drops dramatically.The damage to the nozzle is ultimately caused by solvation and spalling.更多还原