优化10PCuRE炼钢工艺消除铸坯表面纵裂纹

10PCuRE钢是一种C含量较低、P含量很高的稀土钢种,浇铸时难度大,板坯容易产生裂纹和夹杂等缺陷。针对10PCuRE连铸坯表面纵裂缝问题,对原10PCuRE钢冶炼工艺进行了优化,加强了出钢过程的钢液脱氧,并用合成渣技术和强化吹氩搅拌,以改善钢包中的渣—金反应;结晶器中使用专用稀土保护渣以在浇铸过程中有效地防止钢液的二次氧化,较好地润滑初始凝固坯壳和结晶器内模壁,降低表面热裂纹的倾向。应用优化后的冶炼工艺后,钢中氧含量和硫含量得到控制,稀土利用率提高,连铸坯表面纵裂缝消失,铸坯角部裂纹和内部裂纹问题大大改善,并且成品钢成分、晶粒组织、夹杂物的级别均得到了很好的改善。

Improvement of Steelmaking Process of 10PCuRE Steel for Removing the Surface Longitudinal Crack of Slab

10PCuRE is an atmosphere corrosion resistant steel with low carbon content, high phosphor and rare earth elements. The slab is sensitive to cracking and inclusion defects. In order to solve these problems, the steelmaking process was improved. The deoxidation of steel liquid is enhanced, the technology of synthetic slag is applied, and the argon bubbling is strengthen for improvement of slag-metal reaction. The reoxidation was avoided during continuous casting with a powder designed for rare earth steel. It can lubricate the interface of the inside wall of the mould and the shell of steel, therefore decrease the surface cracking. The results show that the content of oxygen and sulfur is controlled,the recovery of rare earths is increased, the longitudinal crack on the surface disappeared , the problems of crack at the corner and inside the slab was dramatically solved after improvement of steelmaking process. With this process, the chemical composition, the microstructure, and the grade of non -metallic inclusions of steel products are also improved.