炼钢 ›› 2020, Vol. 36 ›› Issue (6): 54-60.

• 产品工艺与质量控制 • 上一篇    下一篇

SCX400车轮钢非金属夹杂物控制工艺研究与实践

温  瀚   

  1. (首钢京唐钢铁联合有限责任公司 炼钢作业部,河北 唐山 063200)

  • 出版日期:2020-12-05 发布日期:2020-12-04

Research and practice of non-metallic inclusion control process for wheel steel SCX400

  • Online:2020-12-05 Published:2020-12-04

摘要: 利用扫描电镜分析得出SCX400车轮钢中大尺寸非金属夹杂物主要成分为CaO-MgO-Al2O3,其形成的主要原因是在精炼过程中大尺寸夹杂物没有充分上浮,板卷中存在的低熔点夹杂物在轧制过程中经过变形拉长形成点链状大尺寸夹杂物。采取的工艺优化措施为控制精炼工序RH处理前的夹杂物为易上浮的Al2O3、MgO-Al2O3或低变性的高熔点CaO-MgO-Al2O3;控制板卷中的夹杂物为Al2O3-MgO-CaS系高熔点夹杂物。工艺优化后板卷中夹杂物主要是心部为Al2O3Al2O3-CaO、外圈为CaS的复合夹杂物,在轧制过程未发生明显变形;产品出厂检验过程中夹杂物的初检合格率由优化前的90 %提高至95.4 %,开裂率降至0.5 %~1.0 %,车轮疲劳寿命达到100万次以上。


关键词: 车轮钢, 钙处理, 非金属夹杂物, B类夹杂物, 疲劳开裂

Abstract: The cleanliness problem of SCX400 wheel steel plates was checked by SEM and the results showed that the dot-line macro-inclusions inside the steel plates shaped from the big CaO-MgO-Al2O3 inclusions during rolling process, and those inclusions oriented form refining and casting process, not floating up into slag, consequently kept inside of slabs. Base on this study, actions were implemented to change inclusion into solid classes before RH process as Al2O3, MgO-Al2O3 or high melting point CaO-MgO-Al2O3 who have better tendency to float upon, and then global Al2O3-MgO-CaS inclusions, with high melting point. After that, inclusions were tested as Al2O3 or Al2O3-CaO cores coated by CaS inside the plate. The single-test qualified rate increased from previous 90 % to current 95.4 %, whilst cracking defect rate in production decreased to 0.5 %-1.0 % and the fatigue lifetime of wheels stabilized beyound million times.


Key words: wheel steel, calcium treatment, nonmetallic inclusion, B type inclusion, fatigue crack