GCr15钢浇注过程浸入式水口结瘤的原因及控制

Formation and Control of Blockage at Submerged Nozzle of Mold during GCr15 Steel Casting

南钢第三炼钢厂在浇注GCr15轴承钢的过程中,结晶器浸入式水口形成结瘤。采用扫描电镜和能谱仪、X射线荧光光谱仪分析了水口结瘤的化学成分和形态。结果表明:结瘤物的物相有两种类型,一是由大量MgO·Al2O3颗粒组成的空隙较大的聚集体,二是由MgO·Al2O3颗粒和CaO-Al2O3-MgO基体组成的黏结体。此外,CaO-Al2O3(-MgO)基体的含钙量(质量分数)不均匀,为0.72%~9.91%和11.89%~28.06%。控制钢液洁净度、减少钢液二次氧化、减少耐火材料侵蚀是控制水口结瘤的关键。

A blockage formed at nozzle of mold during casting process of GCr15 bearing steel in 3rd Steel-Making Plant of Nanjing Iron&Steel Co.,Ltd.Chemical composition and form of the nozzle blockage were analyzed by SEM/EDS and X-ray spectrofluometry.The results indicated that there were two types of blockages:one was an aggregate consisting of a large amount of MgO·Al2O3 particles and having larger void and the other was a bonded body consisting of MgO·Al2O3 particles and CaO-Al2O3-MgO matrix.In addition,calcium content(mass fraction)in the CaO-Al2O3(-MgO)matrix was nonuniform,varying from 0.72%-to-9.91%to 11.89%-to-28.06%.Control of cleanliness of molten steel,reduction of both the secondary oxidation of molten steel and the erosion of refractory materials were the key to control nozzle blockage.