中文摘要：

用真空感应炉在800 Pa的Ar气氛中把3.0 kg工业纯铁与合金元素熔化,在1 873 K加入Ce元素精炼10min,制备4种0.08C-0.6Si-0.45Mn-0.3Cu-0.09P-xCe的钢样。用化学成分、SEM和EDS表征结果,研究该体系中洁净度和夹杂物的变化。结果表明[Ce]为0时,夹杂物为MnS-MgO-Al2O3系;[Ce]为0.008%～0.020%时,夹杂物为MgO-Al2O3-Ce2O2S系;[Ce]为0.043%时,夹杂物为FePCe-Ce2O3系,且把7μm以上形状不规则的夹杂物变为2μm球状,甚至转变为0.3μm以下的球形夹杂物,钢材基体上夹杂物残留面积减少58.1%,且尺度均小于3μm。钢液深度净化的原因是,Ce脱O、S后生成的夹杂物上浮、排除,不同类型夹杂物的成因与其形成的热力学条件相关。

英文摘要：

In order to improve the refining process of low carbon and high-strength container plates,four steel samples were prepared by adding Ce into the molten steel containing 0.08C-0.60Si-0.45Mn-0.3Cu-0.09P（mass%） at 1 873 K in a 3.0 kg vacuum induction furnace under Ar atmosphere（800 Pa）.The chemical composition,SEM and EDS analytic results were obtained to study the cleanliness of 0.08C-0.60Si-0.45Mn-0.3Cu-0.09P-xCe（mass%）steel and the change of inclusions.When content was 0,the inclusions were MnS-MgO-Al2O3 system;when content was in the range of 0.008%～0.020%,the inclusions were MgO-Al2O3-Ce2O3 system;when content was 0.043%,the inclusions became FePCe-Ce2O3 system and spherical inclusions of 2 μm or even smaller than 0.3 μm were transformed from 7 μm inclusions with irregular shape.The residual area of inclusions in the steel matrix was reduced by 58.1% and the size of inclusions was below 3 μm approximately.The liquid steel was cleaned profoundly due to the floating up and removal of inclusions which were formed by Ce deoxidation and desulfuration.The formation of different kinds of inclusions was relevant to the relative thermodynamic conditions.