Q345钢250mm×2000mm板坯连铸凝固规律及工艺优化  

Solidification Rule for Casting 250 mm×2000 mm Slab of Steel Q345 and Process Optimization

作　　者：成日金[1] 王志衡 王洪富 夏金魁 曹龙琼 张华[1] 

机构地区：[1]武汉科技大学钢铁冶金及资源利用省部共建教育部重点实验室,武汉430081 [2]武汉钢铁集团鄂城钢铁有限责任公司炼钢厂,鄂州436002

出　　处：《特殊钢》2013年第2期41-44,共4页Special Steel

摘　　要：针对Q345钢(/%:0.14～0.18C、0.20～0.50Si、1.30～1.50Mn、≤0.025P、≤0.025S、0.015～0.060Al)250 mm×2 000 mm板坯中心偏析质量问题,建立凝固传热数学模型,并经射钉试验验证及修正,研究二冷强度(弱冷、中冷、强冷)、连铸速度(0.80～1.10 m/s)对铸坯温度场和坯壳厚度的影响,同时优化轻压下工艺和相应的连铸参数。结果表明,在典型拉速0.95 m/min及弱冷制度下,板坯凝固末端23.43 m,两相区长度7.22 m;减弱冷却强度,凝固末端后移0.56～0.67 m,两相区长度变长0.25～0.29 m;拉速增大0.15 m/min,凝固末端后移3.45～3.90 m,两相区长度变长0.94～1.22 m;优化采用弱冷冷却制度,拉速为0.95 m/min,轻压下位置对应固相率fs=0.4～0.9,总压下量达6 mm时,Q345钢板坯中心偏析Ⅰ级内平均合格率由83.1%提高到98.0%。In according with issue of central segregation of 250 mm × 2 000 mm slab of steel Q345 （/% ： 0. 14 - 0. 18C, 0. 20 -0. 50Si, 1.30 - 1.50Mn, ≤0. 025P, ≤0. 025S, 0. 015 -0. 060A1） , a solidification heat transfer mathe-matical model is established, and verified and modified by nail shooting test to study the effect of secondary cooling intensity （light, middle and strong） and casting speed （0. 80 - 1. 10 m/min） on casting slab temperature field and shell thickness, and optimize the soft reduction process and correspondent casting parameters. Results show that with typical casting speed 0. 95 m/min and light cooling scheduling, the final solidification point of slab is 23.43 m, the length of mushy （ liquid-solidified phase） zone is 7.22 m; with decreasing the secondary cooling intensity, the final solidifying point extends 0. 56 0. 67 m and the length of mushy zone increases by 0. 25 -0. 29 m; with increasing casting speed by 0. 15 m/min, the final solidifying point extends 3.45 - 3.90 m while the length of mushy zone increases by 0. 94 ~ 1.22 m ; with optimized light cooling schedule, casting speed 0. 95 m/rain, solidified fraction fs 0. 4 -0. 9 at soft reduction zone, and total reduction amount 6mm, the qualified percentage for ≤ I ratting central segregation of slab of steel Q345 increases to 98.0% from original 83. 1%.

关 键 词：Q345钢 250mm×2000mm板坯 连铸 数学模型 凝固末端 中心偏析 

分 类 号：TF777[冶金工程—钢铁冶金]