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基于ProCAST软件研究了中间包钢水过热度、连铸坯拉坯速度、连铸机二冷强度等连铸工艺参数对大断面圆坯凝固组织的影响规律。研究结果表明:结晶器电磁搅拌电流为300 A、频率为3 Hz条件下,随着过热度的降低,连铸坯中心等轴晶率显著增加,过热度由49℃降至29℃时,过热度每降低10℃,铸坯中心等轴晶率增大4%左右;拉速由0.16~0.20 m/min每增加0.02 m/min,二冷强度由标准水量的1.5~0.5倍每降低0.5倍,连铸坯中心等轴晶率有所增加但均不显著,均为1.5%左右。降低过热度能够显著细化凝固组织晶粒,而改变拉速和二冷强度对于细化凝固组织晶粒作用不明显。对于调整连铸工艺参数而言,提高连铸坯中心等轴晶率和细化凝固组织晶粒的最有效办法是降低中间包钢水过热度。
Based on ProCAST software, the influence of continuous casting process parameters, such as superheat degree of molten steel in the tundish, continuous casting billet casting speed and secondary cooling strength of continuous casting machine, on the solidified microstructure of large-section round billet was studied. The results show that with the increase of superheat, the equiaxed grain rate in the center of continuous casting slab increases significantly with the electromagnetic stirring current of 300 A and the frequency of 3 Hz. The superheat degree decreases from 49 ℃ to 29 ℃ For each 10 ° C reduction of heat, the equiaxed grain ratio in the center of the slab increases by about 4%; for each increase of 0.02 m / min in pulling speed from 0.16 to 0.20 m / min, the secondary cooling strength is reduced by 0.5 times , Billet center equiaxed grain rate increased but not significant, both about 1.5%. Reducing superheat can remarkably refine the grains of the solidified structure, while changing the pulling speed and secondary cooling intensity has no obvious effect on the grain refinement of the solidified structure. For the adjustment of continuous casting process parameters, the most effective way to increase the equiaxed grain rate in the center of the slab and to refine the grains of the solidified structure is to reduce the superheat of the tundish.