51连铸浸入式水口侵蚀的机理分析及改善措施9-11.docVIP

连铸浸入式水口侵蚀的机理分析及改善措施 叶途明，易卫东，肖卫军，王国平，潘艳华 （武汉钢铁（集团）公司第一炼钢厂，湖北 武汉 430083） 摘 要：简述了连铸中浸入式水口的发展概况，并对铝碳质浸入式水口和铝碳-锆碳质浸入式水口的侵蚀机理进行了叙述。针对浸入式水口在多炉连浇时发生的穿孔以及侵蚀断裂等情况，采取了中间包烘烤下抽风技术、改进水口渣线处的材质、增加渣线处的厚度以及采用二次渣线等方法，使得中间包浸入式水口因侵蚀而穿孔、断裂的情况基本消失，单中包的连浇炉数也有了一定的提高，满足了多炉连浇的生产要求。 关键词：连铸；浸入式水口；侵蚀；机理 Analysis on Corrosion Mechanism of Submerged Entry Nozzle and Countermeasures in Continuous Casting YE Tu-ming, YI Wei-dong, XIAO Wei-jun, WANG Guo-ping, PAN Yan-hua (No. 1 Steelmaking Plant of WISCO, Wuhan 430083, China) Abstract: In the paper, the developmental surveys of submerged entry nozzle (SEN) in continuous casting were overviewed, and the corrosion mechanism of Al2O3-C based SENs and Al2O3-C/ZrO2-C based SENs were described. According to the case of occurred perforation and corroded rupture of SENs in continuous casting, some technologies, such as adopting tundish fire by underside ventilation technology, improved materials of slag line for SENs, increasing the thickness of slag line and introducing double slag lines etc, were adopted. Accordingly, the phenomena of perforation and rupture due to corrosion of SENs were disappeared basically, and the continuous casting heats of single tundish were increased at a certain degree, and the continuous casting production was met. Key words: continuous casting; submerged entry nozzle; corrosion; mechanism 1 前言 武钢第一炼钢厂（以下简称该厂）引进奥钢联的两台五机五流高效方坯连铸机，于1999 年7 月投产设计能力年产钢170万t数不及4 炉数达11可达16[1]。 浸入式水口材质的发展变化大约经历了三个阶段：第一阶段是从上世纪60年代钢铁工业生产中采用连续铸钢技术开始到70年代中期，使用的是熔融石英质水口，但由于炼钢－连铸技术的发展，熔融石英质浸入式水口的使用受到限制，尤其是在浇铸锰钢等特殊钢种时，石英质水口的耐侵蚀性较差，不能满足生产的需要。后来从上世纪70年代末至80Al2O3-C）质[2]。但也存着下列问题：不耐侵蚀而导致在渣线部位形成“缩颈现象”甚至断裂；水口内壁容易被钢水脱氧产物Al2O3等沉积而堵塞水口。并且由于新连铸技术的采用，浇钢温度高，拉速高，保护渣粘度较低，因而保护渣对浸入式水口的侵蚀加剧，Al2O3-C质水口已不能满足这些苛刻条件-锆碳(Al2O3-C/ZrO2-C)质复合浸入式水口：本体主要采用Al2O3-C质，渣线部位采用ZrO2-C质复合材料[3]。这是由于ZrO2具有优良的化学稳定性，难以被以CaO-Al2O3-SiO2系连铸保护渣侵蚀，高温下溶入渣中的ZrO2增强了熔渣的粘度，而未被溶解的ZrO2颗粒又增强了渣的表观粘度，从而降低了保护渣对氧化锆-石墨渣线层的侵蚀，提高了水口的耐蚀性[4]。目前,我国石英质水口的使用寿命为4-5 次，铝碳质水口的使用寿命为5-7次，铝碳－锆碳质复合水口的使用寿命为6-9次[5]。 3 SEN的侵蚀机理