管线钢中液态和固态夹杂物去除率对比

Comparative on removal rate of liquid non-metallic inclusions and solid non-metallic inclusions in pipeline steel

为了比较液态和固态夹杂物的去除率,对比了管线钢冶炼过程中常见的四类典型夹杂物Al_(2)O_(3)、MgO-Al_(2)O_(3)、CaO-Al_(2)O_(3)-CaS、CaO-Al_(2)O_(3)在RH真空处理中的去除率。研究结果表明,钢液中的固态夹杂物比液态夹杂物更容易去除。为了得到液态夹杂物不易去除的原因,采用高温激光共聚焦扫描显微镜原位观察了CaO-Al_(2)O_(3)夹杂物在1600℃钢液中的行为。结果表明,该类夹杂物不易发生聚合长大,随着温度的降低,夹杂物的尺寸进一步增加,其后被凝固基体捕捉。铸坯中大于等于20μm的CaO-Al_(2)O_(3)类夹杂物经轧制后延展就可以造成热轧板中大尺寸夹杂物超标。

In order to compare the removal rates of liquid non-metallic inclusions and solid non-metallicinclusions,the removal rates of four typical inclusions Al_(2)O_(3),MgO-Al_(2)O_(3),CaO-Al_(2)O_(3)-CaS and CaO-Al_(2)O_(3)in pipeline steel during RH vacuum treatment were compared.The results show that solid inclusions in molten steel are easier to remove than liquid inclusions.In order to find out the reason why liquid inclusions are difficult to remove,the behavior of CaO-Al_(2)O_(3)inclusions in molten steel at 1600℃was in-situ observed by high temperature confocal scanning laser microscope.The results show that this kind of inclusion is not easy to polymerize and grow up.With the decrease of temperature,the size of the inclusion further increases,and then it is captured by the solidified matrix.The CaO-Al_(2)O_(3)type inclusions≥20μm in casting slab can cause the large size inclusions exceed the standard in the hot rolled plate.