保护渣对430不锈钢铸坯边部凹陷缺陷的影响  

Effect of mold flux on edge depression defects of 430 stainless steel billet

作　　者：翟俊[1,2] 李欢[1,2] 陈法涛 李晓军 ZHAI Jun;LI Huan;CHEN Fa-tao;LI Xiao-jun(State Key Laboratory of Advanced Stainless Steel Materials,Taiyuan Iron and Steel(Group)Co.,Ltd.,Taiyuan 030003,Shanxi,China;Technology Center,Shanxi Taigang Stainless Steel Co.,Ltd.,Taiyuan 030003,Shanxi,China;No.2 Steelmaking Plant,Shanxi Taigang Stainless Steel Co.,Ltd.,Taiyuan 030003,Shanxi,China)

机构地区：[1]太原钢铁(集团)有限公司先进不锈钢材料国家重点实验室,山西太原030003 [2]山西太钢不锈钢股份有限公司技术中心,山西太原030003 [3]山西太钢不锈钢股份有限公司炼钢二厂,山西太原030003

出　　处：《中国冶金》2022年第5期102-108,共7页China Metallurgy

摘　　要：针对太钢430不锈钢铸坯边部凹陷严重的问题,采用Gleeble 3800、高温原位分析仪、黏度分析仪等技术手段,系统研究430铸坯边部凹陷缺陷的产生机理和保护渣性能对边部凹陷的影响规律。研究结果表明,430铸坯边部凹陷缺陷的主要原因与保护渣的控制传热有关。保护渣碱度过小,结晶能力弱,坯壳在结晶器内冷却强度大,凝固收缩带来较大的角部扭动力而产生边部凹陷,此时铸坯边部凹陷主要发生在结晶器内;保护渣碱度过大,结晶能力强,铸坯冷却强度不够,出结晶器的坯壳厚度薄,在钢水静压力的作用下铸坯宽度产生延展效应,导致后续产生较大的凝固收缩而形成边部凹陷,此时铸坯边部凹陷主要发生在二冷阶段。保护渣碱度控制为1.00,保护渣的结晶能力适宜,既避免了结晶器内强冷带来的铸坯凹陷,又保证了出结晶器坯壳足够的厚度和强度,最终使铸坯边部凹陷深度由1.26 mm降低至0.30 mm,显著改变了铸坯表面质量。Aiming at the serious problem of 430 stainless steel billet depression defects near the slab edge in TISCO, Gleeble 3800, high-temperature in-situ analyzer, viscosity analyzer and other technical means were used to systematically study the generation mechanism of 430 billet depression defects near the slab edge and the influence of mold flux on the depression near the slab edge. The results show that the main reason for 430 stainless steel billet depression defects near the slab edge is related to the controlled heat transfer of the mold flux. The basicity of mold flux is too small, and the crystallization ability is weak, while the cooling strength of billet shell in the mold is large, and solidification shrinkage induces a large corner torsion force, resulting in depression defects near the slab edge. At this moment, the defect mainly occurs in the mold. When the basicity of mold flux is too large, the crystallization capacity is strong, the cooling strength of billet is not enough, and the thickness of billet shell at mold outlet is thin, under the action of hydrostatic pressure of steel, the width of billet becomes wider, which leads to subsequent large solidification shrinkage and the formation of edge depressions. At this moment, the defect mainly occurs in the secondary cooling stage. The basicity of mold flux is controlled at 1.00, the crystallization ability of mold flux is appropriate, which not only avoids the slab depression caused by strong cooling in the mold, but also ensures the sufficient thickness and strength of mold shell, and finally makes depression depth reduced from 1.26 mm to 0.30 mm, which significantly changes the surface quality of billet.

关 键 词：430不锈钢 凹陷 冷却强度 保护渣 碱度 

分 类 号：TF777[冶金工程—钢铁冶金]