50 t EBT EAF-LF( VD) -CC 流程冶炼 25MnB 钢终点B控制的工艺实践

通过电弧炉配加25~36 t/炉铁水,出钢加100 kg铝铁预脱氧,LF精炼过程精炼渣碱度≥4,喂Al线(目标0.015%Al)后加钛铁(目标0.04%Ti),VD后加硼铁,软吹氩5~10 min,连铸全程保护浇铸等工艺措施,25炉25MnB钢(/%:0.23~0.28C，0.15~0.35Si，1.00~1.30Mn，0.0005~0.0030B，≤0.065Ti)Φ180 mm圆坯的O含量为8×10^-6~13×10^-6,N含量为30×10^-6~49×10^-6,B含量0.0015%~0.0024%,B的回收率可达90%,有效地改善了B的控制精度和25MnB钢成品B的命中率。

Process Practice for End B Control of Steel 25MnB Steelmaking by 50 t EBT EAF-LF(VD)-CC Flow Sheet

With the process measures including EAF charging hot metal 25-36 t/heat, during tapping adding 100 kg ferroaluminium to pre-deoxidizing, controlling refining slag basicity ≥ 4 during LF refining, after feeding Al wire ( aim 0.015% Al) adding ferrotitanium (aim 0.04%Ti), after VD adding ferroboron and soft argon blowing for 5-10 min, and whole process shielding casting, the 25 heats production results show that in Φ180 mm round billet of steel 25MnB (/% : 0.23 ~0.28C, 0.15-0.35Si, 1.00-1.30Mr, 0.0005-0.0030B，≤0.065Ti) the oxygen content is 8 x 10^-6-13 x 10^-6, the nitrogen content is 30 x 10^-6-49 x 10^-6 and the boron content is 0.0015% -0.0024% , and the yield of boron is up to 90% , it is available to improve the control extent of boron content and the hitting accuracy of B in finishing steel 25MnB.