低合金Q345B洁净钢生产工艺优化

介绍了莱钢炼钢厂通过采用转炉顶底复吹模式、制定生产冷轧用低合金Q345B钢各工序窄成分控制标准、改进LF精炼工序铝脱氧和钙处理工艺、优化连铸保护浇注工艺、设计Q345B专用保护渣等手段优化工艺流程.生产实践表明,Q345B钢种的成品磷、硫质量分数分别控制在0.025％、0.010％以下,铸坯全氧稳定在0.004％以下,提高了钢水洁净度,降低了夹杂物级别,满足了用户的质量要求.

Optimization of low alloy Q345B clean steel production process

This article introduces the steel-making plant in Laiwu Iron & Steel Company optimizing the process route by means of using the top and bottom combined blowing technique;establishing the criteria of narrow composition control in each step of Q345B low alloy steel production which is used in cold rolling;improvement of LF refining aluminum deoxidization and calcium treatment technology;optimization of protective pouring process and development of exclusive flux for Q345B in continuous casting machine.The productive practice shows that the mass fraction of phosphorus and sulfur in finished Q345B steel is controlled below 0.025% and 0.010% separately;total oxygen in slab is constantly under 0.004%.The cleanness of molten steel is increased and the inclusion content is reduced which meet the demand of customer for quality.