38CrMoAl高铝钢钢水可浇性控制
Castability control of high Al steel 38CrMoAl during continuous casting
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摘要: 38CrMoAl高铝钢由于Al含量较高(Al=0.7%~1.1%,质量分数),在连铸过程中容易导致水口的堵塞,因此需要对钢中Al2O3夹杂物进行形态控制,保证钢水的可浇性.热力学计算和实验研究结果显示:钢中高含量的Al对渣中即使少量的SiO2都具有较强的还原性;不采用传统的精炼喂钙线工艺,而进行转炉出钢过程渣洗操作,能将高熔点的Al2O3转变为低熔点的球状钙铝酸盐夹杂.同时,采用CaO-Al2O3基中间包覆盖剂,以避免钢渣反应导致钢中夹杂物含量增加.工业性试验结果表明,钢水洁净度较高,可浇性好,连续浇注5炉后,水口内壁基本无结瘤现象.Abstract: HighAl content in 38CrMoAl(Al=0.7%-1.1%) is liable to cause nozzle blockage in continuous casting.Shape control of Al2O3 inclusions is needed to ensure the castability of molten steel.The results of thermodynamic calculations and experiments demonstrate that high content in the steel has strong reducibility to SiO2 in slag even with a small quantity,and Al2O3 with a higher melting point can be changed to spherical calcium aluminate inclusions with a lower melting point through slag infiltration during converter tapping instead of the conventional calcium wire feeding process.Meanwhile,the slag-steel reaction,which may cause an increase in the amount of inclusions,can be avoided by using tundish covering fluxes based on CaO-Al2O3 with low SiO2 content.The results of industrial tests show that the steel's cleanness is higher and the castability of molten steel is better.The nozzle has no blockage after five heats of continuous casting steel.