炼钢

• 产品工艺与质量控制(包括特钢) • 上一篇    下一篇

IF钢连铸过程洁净度分析

  

  1. (1. 江苏省(沙钢)钢铁研究院,江苏 苏州 215625;2. 北京科技大学 冶金与生态工程学院,北京 100083)
  • 接受日期:1900-01-01 出版日期:2016-04-05

Purity of IF steel during continuous casting process

  • Accepted:1900-01-01 Online:2016-04-05

摘要: 钢水的洁净度对冷轧薄板的表面质量有重要影响。为解决国内某钢厂弧形铸机生产IF钢表面缺陷发生率较高的问题,利用Aspex扫描电镜、LECO TCH600氧氮氢分析仪对某钢厂IF钢中间包钢水及连铸坯的洁净度进行了分析。分析结果表明:该钢厂生产的IF钢中间包钢水w(T.O)=(17.5~35.7)×10-6,洁净度较高,但开浇过程发生的二次氧化造成约60 t钢水不合格;IF钢铸坯中大型夹杂物主要为簇群状的Al2O3夹杂物和“气泡+Al2O3夹杂物”结构,大于50 μm的夹杂物数量为0.29~0.63个/cm2,夹杂物控制水平较高。此外,分析过程中首次在距表层20 mm附近发现了大尺寸“气泡+Al2O3夹杂物”结构的聚集现象,并提出了降低钢液硫含量、适当减少塞棒吹氩量以及优化结晶器流场等改善措施。

关键词: IF钢, 洁净度, 夹杂物, 气泡

Abstract: Purity of steel is vital important to the surface quality of cold rolled sheet. Samples of tundish steel and slab were analyzed by automatic feature analysis equipped on Aspex and LECO TCH600 in present paper to solve the problem of high surface defects occurring rate. T.O mass fraction of IF steel in tundish is in the range of 17.5×10-6 to 35.7×10-6, which means high purity. But about 60 t of steel become unqualified because of the reoxidation at the start of casting. Macro inclusions in the slab mainly are cluster Al2O3 inclusions and “bubble + Al2O3 inclusion” structures. The quantity density of inclusions over 50 〖WT〗μ〖WT9.5B4〗m is in the range of 0.29/cm2 to 0.63/cm2. Moreover, a new gathering area which is different from the one just blow the surface of macro “bubble + Al2O3inclusion” structures is found 20.0mm away from the surface. Measures such as lowering the sulphur content of steel, prudently lowering the argon amount from the stopper, and optimize the flow condition in the mold, are proposed to reduce the gathering phenomenon.

Key words: IF steel, purity, inclusions, bubbles