高级别船板钢炉外精炼过程洁净度研究

摘要

Three heats of industrial trials were performed to investigate the cleanliness of A32 ship plate steel produced by a BOF- LF- RH- CC route. The variation of T. O and [N] contents as well as the transformation route and mechanism of inclusions in the steel were studied by system sampling during secondary refining processes. The steel have high level cleanliness with the T. O content under 2 × 10 - 5 and the [N] content under 4 × 10 - 5 in tundish samples. The T. O content, number density and average size of inclu-sions decrease during the LF refining process, and the inclusions transform into a CaO- MgO- Al2 O3 ternary system. In the RH refining process, the T. O content and the number density of inclusions decrease, but the average size of inclusions increases. During calcium treatment, the number density of inclusions increases but the average size of inclusions decreases, and the inclusions transform into a CaO- Al2 O3- CaS ternary system.%为了研究采用 BOF- LF- RH- CC 工艺生产的 A32船板钢洁净度水平，进行了三炉工业实验。通过对冶炼过程系统取样分析，研究了钢中总氧、氮含量变化，夹杂物的转变规律及机理。结果表明：该工艺生产的船板钢有较高的洁净度，中包总氧控制在2×10-5以下，氮含量控制在4×10-5以下；LF 精炼过程中，钢中总氧、夹杂物数量密度和平均尺寸均降低，夹杂物转变为 CaO- MgO- Al2 O3三元系；RH 精炼过程中，钢中总氧和夹杂物数量密度降低，而夹杂物平均尺寸升高；钙处理过程中，夹杂物数量密度升高，而夹杂物平均尺寸降低，夹杂物转变为 CaO- Al2 O3- CaS 三元系。