连铸二冷系统喷嘴堵塞物来源分析和控制措施

连铸二冷喷嘴堵塞会造成冷却水分布不均匀,导致铸坯表面温差大,使铸坯产生裂纹缺陷,严重降低轧材的成材率。针对湘钢4号小方坯连铸机出现的喷嘴频繁堵塞问题,全面、系统分析了喷嘴堵塞物类型及其来源,并提出了相应控制措施。分析结果表明,喷嘴堵塞物主要分为4种类型,即边角突出的致密铁氧化物,球形铁氧化物,含P、Si、Ca的无定形氧化物和多孔疏松结构的铁氧化物,其来源于水站沉淀池和连铸反冲洗过滤器后的碳钢材质部件结垢物。当反冲洗过滤器后的碳钢材质部件更换为不锈钢材质后,喷嘴堵塞物中多孔疏松结构的铁氧化物消失,喷嘴堵塞现象明显改善,最大喷嘴堵塞数量由5~8个减少为0~2个。

Source analysis and control measures of nozzle blockage in continuous casting secondary cooling system

The clogging of secondary cooling nozzle for continuous casting would cause uneven distribution of cooling water, which leads to large temperature difference on the surface of billet, resulting in crack defects of billet and seriously reducing the yield of rolled products. In view of the frequent nozzle clogging for No.4 billet caster in Xianggang, types and sources of nozzle blockage were comprehensively and systematically analyzed, and the corresponding control measures were put forward. The analysis results show that the nozzle clogging materials are mainly divided into four types, dense iron oxide with prominent edges and corners, spherical iron oxide, amorphous oxide containing P, Si and Ca and iron oxide with porous and loose structure, which come from the scaling of carbon steel parts behind the sedimentation tank of water station and continuous casting backwash filter. When the carbon steel parts behind the backwash filter are replaced with stainless steel, the iron oxide with porous and loose structure in the nozzle blockage disappears, the nozzle blockage is significantly improved, and the maximum number of nozzle blockage is reduced from 5-8 to 0-2.