V-微合金化高强度钢Q420C 180 mm×180 mm连铸坯热塑性的研究  

A Study on Hot Ductility of 180 mm×180 mm Casting Bloom of V-Microalloying High Strength Steel Q420C

作　　者：赵斌[1] 崔怀周[1] 汪成义[1] 吴巍[1] 王欣 

机构地区：[1]钢铁研究总院冶金工艺研究所,北京100081 [2]河北钢铁集团唐山钢铁有限责任公司,唐山063000

出　　处：《特殊钢》2017年第6期11-15,共5页Special Steel

摘　　要：试验用Q420C钢(/%:0.18C,0.34Si,1.40Mn,0.013P,0.011S,0.066V,0.018Als,0.011 0N)铸坯的冶炼工艺为80 t BOF-LF-CC。采用Gleeble-1500D热模拟试验机测试Q420C钢连铸坯的600~1400℃热塑性,并利用金相显微镜、扫描电镜以及透射电子显微镜分析断口形貌及金相组织和研究凝固偏析和析出物粒子对铸坯热塑性的影响。结果表明,Q420C钢第Ⅰ脆性区为>1250~1350℃;第Ⅲ脆性区为700~1050℃;在1050~1250℃,断面收缩率大于60%。工业试验结果表明,通过控制Als含量0.015%~0.020%,适当降低二冷比水量(足辊段7~8t/h,Ⅰ段5.5~6.5 t/h,托辊段14±1t/h),铸坯矫直温度≥1050℃,轧材开裂率由原45.3%降至4.6%。The steelmaking flowsheet of tested casting bloom of steel Q420 C（/% ： 0. 18 C, 0. 34 Si, 1.40 Mn,0.013 P, 0.011 S, 0.066 V, 0.018 Als, 0.0110 N） is 80 t BOF-LF-CC process. The hot ductility of casting bloom of steel Q420 C at 600~1 400℃is tested by using Gleeble-1500 D thermal simulator and the morphology of fracture and structure of steel is analyzed by optical, scanning-and transmission-electron microscope to study effect of the solidification segregation and precipitates on hot ductility of casting bloom. Results show that of steel Q420 C the Ⅰ brittle zone is 〉 1250~1350℃ and the Ⅲ brittle zone is 700 ~1050℃, and at 1050~1250℃ the steel has better ductility with reduction of area more than 60%. Commercial pilot production results show that with controlling Als content in steel 0.015%~0.020%,properly decreasing ratio of secondary cooling water to 7 ~8 t/h at feet roller zone,5. 5~6. 5 t/h at I zone and 14 ± 1.t/h at support roller zone, and controlling straightening temperature of casting bloom ≥1050℃, the cracking ratio of rolled products decreasing from original 45. 3% to 4. 6%.

关 键 词：V-微合金化钢Q420C 热塑性 析出物 断口形貌 

分 类 号：TF777[冶金工程—钢铁冶金]