提高管线钢洁净度的工艺技术研究

Study on Technology for Improving Cleanliness of Pipeline Steel

利用金相显微镜、扫描电镜等对管线钢夹杂物的成分、形态及成因进行了分析,对管线钢不同生产工艺路线对钢质洁净度的影响进行了研究。结果表明,采用转炉-RH-LF-钙处理-连铸工艺,将钙处理后的钢水弱吹氩时间从3~5 min提升至8~10 min,D类夹杂由1.0级提高至0.5级,Ds类夹杂由1.0级提高至0级和0.5级；采用转炉-LF-RH-钙处理-连铸工艺,可以实现A、B、C类夹杂0级、D类夹杂1.0级、Ds类夹杂多数0级、少量0.5级的效果。

By means of metallurgical microscope and scanning electron microscope, the com-positions of inclusions in pipeline steel, forms of these inclusions and causes of their formations were analyzed and then the effect of different productive technologies for manufacturing pipeline steel on its cleanliness was also investigated. The study results show that the weak argon-blowing time for the molten pipeline steel after carrying out the calcium treatment by using the converter-RH-LF-calcium treatment-continuous casting raises from the interval between 3 and 5 minutes to the interval between 8 and 10 minutes, the Type D inclusions improve to Level 0.5 from Level 1.0 while the Type Ds inclusions improve to Level 0 or Level 0.5 from Level 1.0. However if the con-verter-LF-RH-calcium treatment-continuous casting technology is used, these types of inclusions such as Type A, Type B and Type C can reach to Level 0, Type D inclusions can reach to Level 1.0 while most of Type Ds inclusions can reach to Level 0 with less Level 0.5 inclusions.