袁保辉, 刘建华, 周海龙, 黄基红, 张硕, 申志鹏. RH强制脱碳与自然脱碳工艺生产IF钢精炼效果分析[J]. 工程科学学报, 2021, 43(8): 1107-1115. DOI: 10.13374/j.issn2095-9389.2020.10.10.002
引用本文: 袁保辉, 刘建华, 周海龙, 黄基红, 张硕, 申志鹏. RH强制脱碳与自然脱碳工艺生产IF钢精炼效果分析[J]. 工程科学学报, 2021, 43(8): 1107-1115. DOI: 10.13374/j.issn2095-9389.2020.10.10.002
YUAN Bao-hui, LIU Jian-hua, ZHOU Hai-long, HUANG Ji-hong, ZHANG Shuo, SHEN Zhi-peng. Refining effect of IF steel produced by RH forced and natural decarburization process[J]. Chinese Journal of Engineering, 2021, 43(8): 1107-1115. DOI: 10.13374/j.issn2095-9389.2020.10.10.002
Citation: YUAN Bao-hui, LIU Jian-hua, ZHOU Hai-long, HUANG Ji-hong, ZHANG Shuo, SHEN Zhi-peng. Refining effect of IF steel produced by RH forced and natural decarburization process[J]. Chinese Journal of Engineering, 2021, 43(8): 1107-1115. DOI: 10.13374/j.issn2095-9389.2020.10.10.002

RH强制脱碳与自然脱碳工艺生产IF钢精炼效果分析

Refining effect of IF steel produced by RH forced and natural decarburization process

  • 摘要: 西昌钢钒厂由于转炉热量不足而以转炉—LF精炼—RH精炼—连铸工艺生产IF钢,为探究RH强制脱碳与自然脱碳工艺生产IF钢精炼效果,采用生产数据统计、氧氮分析、夹杂物自动扫描、扫描电镜和能谱分析等手段,对不同脱碳工艺对顶渣氧化性以及钢的洁净度影响进行了详细研究。结果表明:(1)与自然脱碳工艺炉次相比,采用强制脱碳工艺的炉次在转炉结束与RH进站钢中的平均O含量更低;(2)两种工艺脱碳结束钢中的O含量基本在同一水平;(3)强制脱碳工艺的炉次在RH结束时渣中平均T.Fe的质量分数降低了1.3%。在能满足RH脱碳效果的前提下,尽量提高转炉终点钢液碳含量、降低钢液氧含量,后续在RH精炼时采用强制吹氧脱碳工艺,适当增大吹氧量来弥补钢中氧,可显著降低IF钢顶渣氧化性。自然脱碳工艺与强制脱碳工艺控制热轧板T.O含量均比较理想;与自然脱碳工艺相比,强制脱碳工艺可有效降低IF钢N含量,这与强制脱碳工艺真空室内碳氧反应更剧烈所导致的CO气泡更多和气液反应面积更大有关。脱碳工艺对IF钢热轧板中夹杂物类型、尺寸及数量没有明显影响,夹杂物主要由Al2O3夹杂、Al2O3–TiOx夹杂与其他类夹杂物组成,以夹杂物的等效圆直径表示夹杂物尺寸,以上三类夹杂物平均尺寸分别为4.5、4.4和6.5 μm,且钢中尺寸在8 μm以下的夹杂物数量占比高于75%。在RH精炼过程中,尽量降低RH脱碳结束钢中O含量,有利于提高钢液洁净度。

     

    Abstract: Owing to insufficient converter heat, IF steel is produced via the BOF—LF—RH—CC process in the Xichang Steel & Vanadium Co.LTD of Pangang Group, Xichang, China. To explore the refining effect of IF steel produced via the RH forced and natural decarburization process, this work employed standard analysis methods such as production data statistics, total oxygen and nitrogen analysis, automatic scanning electron microscopy, scanning electron microscopy, and energy spectroscopy. The effects of different decarburization processes on the ladle slag oxidability and cleanliness of steel were investigated in detail. Compared with the natural decarburization process heats, results show that the forced decarburization process heats exhibit (1) lower average O content in molten steel after BOF and before RH, (2) a similar level of the O content in molten steel after decarburization with that of the natural decarburization process, and (3) 1.3% lower average T.Fe mass fraction in the ladle slag after RH treatment. To ensure the RH decarburization effect, the final carbon content increased and molten steel oxygen content reduced in the converter to the maximum extent. The forced oxygen blowing decarburization process was then used to compensate for the molten steel oxygen content during RH refining by increasing oxygen blowing properly, which can significantly decrease the ladle slag oxidability of IF steel. Both the natural decarburization and forced decarburization processes are ideal for controlling the T.O content of a hot–rolled sheet. Compared with the natural decarburization process, the forced decarburization process can effectively reduce the N content of IF steel, which is related to a more violent carbon–oxygen reaction in a vacuum chamber, resulting in a high volume of CO bubbles and a large gas–liquid reaction area. The decarburization process has no obvious influence on the type, size, and number of inclusions in the hot–rolled sheet of IF steel that mainly consist of Al2O3, Al2O3–TiOx, and other inclusions. The average sizes of the above three 4.5, 4.4, and 6.5 μm, respectively, according to the equivalent circle diameter of inclusions. In addition, more than 75% of inclusions are within 8 μm. During the RH refining process, reducing the O content in molten steel after RH decarburization to the maximum extent is beneficial to improve the cleanliness of molten steel.

     

/

返回文章
返回