40CrB冶炼过程中氮含量的控制

Control of Nitrogen Content during Smelting of 40CrB Steel

以莱钢50t电炉生产线生产40CrB的冶炼过程为对象，来研究含硼钢冶炼过程中氮含量的变化情况。经研究表明：硼钢冶炼过程中的氮含量呈现先降低后增加再降低再增加的变化趋势，整个，台炼过程电炉终点氮含量最低，连铸坯氮含量最高，VD处理有利于降低氮含量。电炉出钢至精炼阶段，氮含量增加最为明显，其次是连铸阶段。针对冶炼过程的不同阶段，采取有效的措施可以有效的将钢中的氮含量控制在50×10^-6以下。

Considering the smelting process of 40CrB steel in 50 t EAF production lines in the special steel plant in Laigang, the change of nitrogen content during the smelting process of boron steel was analyzed. Research showed that, the nitrogen content demonstrated a change trend first decreasing then increasing during the smelting process of boron steel, the lowest at the end of electric furnace and the highest in the continuous casting slab during the whole smelting process, and VD treatment was helpful to decrease the nitrogen content. The increase of nitrogen content was most obvious between the tapping from EAF and the refining stage, next came the continuous casting stage. Aiming at the different stages during the smelting process, the effective measures were taken to effectively control the nitrogen content below 50ppm.