非稳态连铸坯洁净度的定量研究  

Quantitative research on cleanliness of unsteady continuously cast slabs

作　　者：朱国森[1] 王新华[2] 邓小旋[2] 季晨曦[1] 陈斌[1] 

机构地区：[1]首钢技术研究院,北京100043 [2]北京科技大学冶金与生态工程学院,北京100083

出　　处：《炼钢》2013年第6期41-47,52,共8页Steelmaking

摘　　要：采用Aspex Explorer电镜对“KR铁水脱硫-转炉脱磷-转炉脱碳-RH精炼-板坯连铸”工艺路线生产的DC06（IF钢）连铸坯洁净度进行了定量研究，试样检测面积在9382．8～52061砌m2。研究发现：IF钢铸坯中的夹杂物主要有5种类型，分别是簇群状Al2O3夹杂物、块状Al2O、A1203·TiOx系类球状夹杂物、保护渣卷入造成的夹杂物和“气泡＋Al2O3”类夹杂物。正常铸坯具有很高的洁净度，w（T．0）=0．0010％～0．0013％，大于50um夹杂物平均为0．31个／cm2，并且未检测到来源于保护渣卷入形成的50um以上夹杂物。在试验采用的拉速范围内（1．0～1．5m／rain），正常浇铸铸坯试样中检测到的大于50um夹杂物数量随拉速增加而降低。在各类非稳态浇铸铸坯中，开浇阶段第1块铸坯（头坯）品质降低最为严重，不能用于生产有表面质量要求的汽车、家电等冷轧钢板；开浇阶段第2块铸坯、快换水口铸坯和尾坯中50um以上夹杂物数量明显高于正常铸：区，用于汽车钢板生产应采用表面清理或降级；交换钢包交接坯和倒数第2块铸坯和正常铸坯洁净度水平相当，可以用于汽车钢板的生产。Aspex Explorer SEM was applied to investigate cleanliness of unsteady continuously cast IF slabs produced by the route ＂KR desulphurization-BOF dephosphurization-BOF decarburization--RH-CC＂. The analyzed area of each slab sample ranges from 9 382. 8 to 52 061 mm2. The results indicate that there are five different types of non-metallic inclusions in continuously cast IF slabs such as alumina cluster, alumina lump, spherical Al2O3 TiOx, entrapped mold powder, and bubble with alumina. Normal slabs have very high cleanliness with mass ffaction of total oxygen changing ftom 0. 001 % to 0. 001 3 % and the density of inclusions bigger than 50 um is about 0.31/cm2. Entrapped mold powder is not found in such slabs. When the casting speed changes from 1.0 to 1.5 m/min, the density of inclusions bigger than 50 um decreases with the increase of casting speed. Among the unsteady continuously cast slabs, the quality of first slab is the worst and it cannot be used for auto and home appliance purpose which need high surface quality. The densities of inclusions bigger than 50/ira in the second slab, SEN exchange slab and last slab are higher than that of normal slabs. When they are used for auto purpose, they should be downgraded or scarfed. The quali- ties of ladle exchange slab and the last but one slab are the same level as normal slabs. They can be used for auto purpose.

关 键 词：IF钢 非金属夹杂物 非稳态 保护渣 连铸 

分 类 号：TF777[冶金工程—钢铁冶金]