Abstract: The process flowsheet of 1. 2 mm cold-rolled sheet of steel DC04-LQQ (/% : ≤0.003 5C, ≤ 0.02Si, 0. 08 ~0. 20Mn, ≤ 0. 015P, ≤ 0. 012S, 0. 02 ~ 0. 06Als, 0. 06 ~ 0. 08Ti,≤0.0040N) is hot metal pretreatment-250 t BOF-RH-slab casting-hot-rolling- cold-rolling- annealing at 820 -840 °C. The analysis on surface defects of deep-drawing piece of steel DC04-LQQ for filter has been carried out； the results show that the main surface defects are tongue-shaped and pinhole-shaped defects, the tongue-shaped surface defects containing O, Al, Mg and Fe etc elements are formed by Al₂O₃ and MgO inclusions in liquid and the pinhole-shaped surface defects containing K, Na, Ca, Al and Ti etc elements are formed by entrapped mold powder in condition of large fluctuation of mold liquid surface. With the measures including increasing holding time of liquid from original 20 min to 30 min, extending the interval between adding Al deoxidizing and adding alloys from 1 ~2 min to 4 min in RH refining, optimizing tundish argon blowing scheme and revamping the tundish cover argon pipeline, and increasing the tundish argon pipe diameter from original 20 mm to 34 mm, the occurring rate of surface defects of steel for filter decreases from original 7. 78% to 2. 62% to get obvious effect.

摘要： DC04-LQQ钢（/%:≤0.003 5C,≤0.02Si,0.080.20Mn,≤0.015P,≤0.012S,0.020.06Als,0.060.08Ti,≤0.004 0N）1.2 mm冷轧板的工艺流程为铁水预处理-250 t BOF-RH-板坯连铸-热轧-冷轧-820~840℃退火。对DC04-LQQ钢滤清器深冲件表面缺陷进行了分析,结果表明,主要表面缺陷为舌状和针孔状缺陷,舌状表面缺陷部位含有O、Al、Mg和Fe等元素,其主要是钢水中Al₂O₃和MgO夹杂所致。针孔状表面缺陷部位含有K、Na、Ca、Al和Ti元素,其主要是结晶器液面波动大造成保护渣卷入所致。通过增加钢水静置时间从20 min至30 min、延长RH精炼Al脱氧和合金化之间的时间间隔由12 min至4 min、优化中间包吹氩制度和改造中间包包盖氩气管路、中间包氩气直径由原20 mm增至34 mm等措施,滤清器用钢表面缺陷率由原7.78%降低至2.62%,取得了显著效果。